U.S. patent application number 13/968908 was filed with the patent office on 2015-01-01 for method, computer program and system providing real-time power grid hypothesis testing and contigency planning.
This patent application is currently assigned to International Business Machines Corporation. The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Robert F. Enenkel, Michael P. Perrone.
Application Number | 20150006141 13/968908 |
Document ID | / |
Family ID | 52116430 |
Filed Date | 2015-01-01 |
United States Patent
Application |
20150006141 |
Kind Code |
A1 |
Enenkel; Robert F. ; et
al. |
January 1, 2015 |
METHOD, COMPUTER PROGRAM AND SYSTEM PROVIDING REAL-TIME POWER GRID
HYPOTHESIS TESTING AND CONTIGENCY PLANNING
Abstract
A data processing system includes a user interface with a user
input configured to enable a user to specify a type of simulation
to be performed and at least one initial condition, where the
simulation is executed using at least one sensor input from a grid
structure composed of at least one of a power transmission and
distribution grid. The user interface further has a display
configured to visualize a representation of a result of a
simulation of at least one scenario by presenting a
multi-dimensional representation comprised of indicators, where
each indicator corresponds to at least one simulation result. The
user interface responds to a selection of one of the indicators by
the user to visualize a result of the corresponding simulation. The
type of simulation can be an N-k contingency analysis simulation,
where k is equal to zero, 1 or greater than 1.
Inventors: |
Enenkel; Robert F.;
(Markham, CA) ; Perrone; Michael P.; (Yorktown
Heights, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Assignee: |
International Business Machines
Corporation
Armonk
NY
|
Family ID: |
52116430 |
Appl. No.: |
13/968908 |
Filed: |
August 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13956452 |
Aug 1, 2013 |
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13968908 |
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61839519 |
Jun 26, 2013 |
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Current U.S.
Class: |
703/18 |
Current CPC
Class: |
H02J 13/00017 20200101;
H02J 2203/20 20200101; Y04S 40/124 20130101; G06F 2119/06 20200101;
H02J 13/0006 20130101; G06F 30/18 20200101; Y02E 60/00 20130101;
Y04S 40/20 20130101; H02J 3/00 20130101; G06F 30/367 20200101 |
Class at
Publication: |
703/18 |
International
Class: |
G06F 17/50 20060101
G06F017/50 |
Claims
1. A system comprising: a computing platform comprising a first
interface to receive inputs from sensors that comprise a part of a
grid structure comprised of at least one of a power transmission
grid and a power distribution grid, the computing platform
configured to execute an electrical power grid simulator program
and further comprising a second interface configured to communicate
with at least one user device through a communication layer; and a
user device connected with the computing platform through the
communication layer, the user device comprising a graphical user
interface, at least one data processor, and at least one
non-transitory computer readable medium that stores program
instructions, where execution of the stored program instructions
enables the user device to specify, in response to input from the
graphical user interface, at least one initial condition and a type
of simulation to be performed by the electrical power grid
simulator program based on the at least one initial condition; to
transmit the specified type of simulation and the at least one
initial condition from the user device to the computing platform;
to receive from the computing platform a result of the simulation
at the user device, the simulation being based on at least one of a
steady state model of the grid structure and a dynamical model of
the grid structure; and to visualize the result of the simulation
with the user interface, where a visualization of the result
comprises a result of the simulation of at least one scenario and
displays a multi-dimensional representation comprised of
indicators, where each indicator corresponds to at least one
simulation result, and where a user selection of one of the
indicators initiates visualizing a result of the simulation of the
corresponding simulation result or results.
2. The system as in claim 1, where the type of simulation comprises
an N-k contingency analysis simulation, where k is equal to zero, 1
or greater than 1, where binomial coefficient N choose k scenarios
are generated, and each scenario has k generators and/or branches
disabled.
3. The system as in claim 2, where a visualization comprises at
least one of power flow, generation or demand of the grid structure
comprising one or more of active and reactive power flow,
generation or demands, phase angles, maximum, average, or minimum
values and other relevant parameters of interest.
4. A data processing system comprised of at least one data
processor and at least one memory medium connected with the at
least one data processor, the at least one memory medium storing
computer program instructions that are executable by the at least
one data processor, the data processing system further comprising:
a user interface having a user input configured to enable a user to
specify a type of simulation to be performed and at least one
initial condition, where the simulation is executed by a simulation
program using at least in part one or more sensor inputs from a
grid structure comprised of at least one of a power transmission
grid and a power distribution grid, said user interface further
having a display configured to visualize a representation of a
result of a simulation of at least one scenario by presenting a
multi-dimensional representation comprised of indicators, where
each indicator corresponds to at least one simulation result, where
said user interface is further configured to respond to a selection
of one of the indicators by the user to visualize a result of the
corresponding simulation.
5. The data processing system of claim 4, where the simulation is
based on at least one of a steady state model of the grid structure
and a dynamical model of the grid structure.
6. The data processing system of claim 4, where a type of
simulation comprises an N-k contingency analysis simulation, where
k is equal to zero, 1 or greater than 1, where binomial coefficient
N choose k scenarios are generated, and each scenario has k
generators and/or branches disabled.
7. The data processing system of claim 4, where a simulation
enables real-time or near real-time operation of the grid structure
to be monitored and simulated.
8. The data processing system of claim 4, where the visualization
comprises a visualization of at least one of power flow, generation
or demand of the grid structure comprising one or more of active
and reactive power flow, generation or demands, phase angles,
maximum, average, or minimum values and other parameters of
interest.
9. The data processing system of claim 4, where said user interface
is further configured to enable the user to interact with at least
one running simulation to visualize with said display real-time
grid data or evolving simulation data, and to request via said user
input additional simulation detail.
10. The data processing system of claim 4, where specifying the
simulation with said user interface comprises at least one of a
selection of initial grid states for the simulation and a selection
of grid structure variations whose effect on the grid structure is
to be simulated, where initial grid states can be based on
historical grid structure data or on real-time grid structure data
captured at least in part by the sensors.
11. The data processing system of claim 4, where the visualization
provides periodic visualization updates as simulation results
become available to be visualized, and where said user interface is
further configured to enable the user to interact with a running
simulation to modify a future path of the running simulation based
on the visualization.
12. The data processing system of claim 11, where enabling the user
to interact with a running simulation enables the user to prune a
simulation scenario space in order to concentrate available
computing power on simulation paths of interest to the user.
13. The data processing system of claim 4, where specifying the
simulation with said user interface comprises enabling the user to
select from a visualization of the grid structure at least one of
individual nodes or branches of the grid structure, or to select at
least one region of the grid structure that includes multiple nodes
and branches.
14. The data processing system of claim 13, where specifying the
simulation with said user interface further comprises enabling the
user via said user input to selectively add at least one element to
the grid structure, to selective remove at least one element from
the grid structure, or to selectively replace at least one existing
element of the grid structure with another element.
15. The data processing system of claim 4, where the visualization
is comprised of graphical-type images and also alpha-numeric
information for further specifying a result of a simulation or
simulations.
16. The data processing system of claim 4, where the visualization
displays a graphical representation of a state of the grid
structure or grid structure simulation at past, current or future
times, and responds to user activation of said user interface to
direct and control operation of the simulation including setup, run
time and analysis.
17. The data processing system of claim 4, where the visualization
shows a difference between results of at least two simulations of
the grid structure.
18. The data processing system of claim 4, where specifying the
simulation with said user interface further comprises specifying
multiple simulation scenarios, and further comprises selecting a
starting simulation scenario, a number of simulation scenarios to
be generated, and specifying at least one rule to be applied for
generating the multiple simulation scenarios.
19. The data processing system of claim 4, where said user
interface is further configured to send in response to a user input
a command to the grid structure in order to change a state of at
least one grid structure actuator.
20. The data processing system of claim 4, embodied in a mobile
device that is connectable via at least one wireless interface to a
computing platform where the simulation is performed.
Description
CLAIM OF PRIORITY FROM COPENDING PROVISIONAL PATENT APPLICATION
[0001] This patent application claims priority under 35 U.S.C.
.sctn.119(e) from Provisional Patent Application No. 61/839,519
filed on Jun. 26, 2013, the disclosure of which is incorporated by
reference herein in its entirety.
CROSS-REFERENCE TO A RELATED PATENT APPLICATION
[0002] This patent application is a continuation patent application
of copending U.S. patent application Ser. No. 13/956,452, filed
Aug. 1, 2013, the disclosure of which is incorporated by reference
herein in its entirety.
TECHNICAL FIELD
[0003] The exemplary embodiments of this invention relate generally
to simulation methods and systems and, more specifically, relates
to transmission and distribution power grid simulation methods and
systems.
BACKGROUND
[0004] Electrical power grids, also referred to as transmission
grids and distribution grids, are critical components of modern
society. Power outages of any duration can lead to significant
economic and personal losses. It has become essential for utilities
and governments to plan for and to provide a sufficient degree of
robustness for growing networks of millions of interconnected
electrical power generators and users.
[0005] Many electrical power grids have thus far grown organically,
without overarching coordination. Electrical utilities are
exploring methods to evaluate the sensitivity, reliability,
robustness and risk of the grid in real time; however, they
currently can only do so in very limited ways.
[0006] Due to the growing complexity of electrical power grids and
the increasing societal demands for efficiency, resiliency,
security and reliability of these power grids, there is a need for
an ability to monitor, simulate, predict and react pro-actively to
any threats to power grid performance, as well as to model the
complex, dynamically changing power grid network in real time, to
identify potential problems before they arise and take appropriate
action before catastrophic failure occurs.
SUMMARY
[0007] In accordance with a first aspect of the embodiments of this
invention there is provided a method to simulate operation of a
grid structure. The method includes specifying a type of simulation
to be performed and at least one initial condition with a user
interface of a user device; transmitting the specified type of
simulation and the at least one initial condition from the user
device to a computing platform; receiving from the computing
platform a result of the simulation at the user device, where the
simulation is based on at least one of a steady state model of the
grid structure and a dynamical model of the grid structure; and
visualizing the result of the simulation with the user interface. A
visual representation of the result shows a result of the
simulation of at least one scenario. Visualizing comprises
displaying a multi-dimensional representation comprised of
indicators, where each indicator corresponds to at least one
simulation result, and further comprises upon a selection of one of
the indicators visualizing a result of the simulation of the
corresponding simulation result or results.
[0008] The method can be performed as a result of execution of
computer program instructions stored in a computer-readable medium
by a data processor, where the computer-readable medium and the
data processor comprise a part of the user device.
[0009] In accordance with a further aspect of the embodiments of
this invention there is provided a system that includes a computing
platform comprising a first interface to receive inputs from
sensors that comprise a part of a grid structure comprised of at
least one of a power transmission grid and a power distribution
grid. The computing platform is configured to execute an electrical
power grid simulator program and further comprises a second
interface configured to communicate with at least one user device
through a communication layer. The system further comprises a user
device connected with the computing platform through the
communication layer. The user device comprises a graphical user
interface, at least one data processor, and at least one
non-transitory computer readable medium that stores program
instructions. Execution of the stored program instructions enables
the user device to specify, in response to input from the graphical
user interface, at least one initial condition and a type of
simulation to be performed by the electrical power grid simulator
program based on the at least one initial condition; to transmit
the specified type of simulation and the at least one initial
condition from the user device to the computing platform; to
receive from the computing platform a result of the simulation at
the user device, the simulation being based on at least one of a
steady state model of the grid structure and a dynamical model of
the grid structure; and to visualize the result of the simulation
with the user interface. A visualization comprises a result of the
simulation of at least one scenario and displays a
multi-dimensional representation comprised of indicators, where
each indicator corresponds to at least one simulation result, and
where a user selection of one of the indicators initiates
visualizing a result of the simulation of the corresponding
simulation result or results.
[0010] In accordance with another aspect of the embodiments of this
invention there is provided a data processing system comprised of
at least one data processor and at least one memory medium
connected with the at least one data processor. The at least one
memory medium stores computer program instructions that are
executable by the at least one data processor. The data processing
system further comprises a user interface having a user input
configured to enable a user to specify a type of simulation to be
performed and at least one initial condition, where the simulation
is executed by a simulation program using at least in part one or
more sensor inputs from a grid structure comprised of at least one
of a power transmission grid and a power distribution grid. The
user interface further has a display configured to visualize a
representation of a result of a simulation of at least one scenario
by presenting a multi-dimensional representation comprised of
indicators, where each indicator corresponds to at least one
simulation result. The user interface is further configured to
respond to a selection of one of the indicators by the user to
visualize a result of the corresponding simulation.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1A illustrates a high level block diagram of an example
of a system that is configured to implement the embodiments of this
invention.
[0012] FIG. 1B shows another view of the system depicted in FIG.
1A.
[0013] FIG. 1C is a graph that shows an example of N-k contingency
hardware requirements, in this example an estimated number of Blue
Gene/Q cores required to run an N-k contingency simulation in one
minute, versus k.
[0014] FIG. 2 shows an exemplary display at the mobile device shown
in FIGS. 1A and 1B of an initial visualization of a grid system
topology.
[0015] FIG. 3 shows an exemplary display at the mobile device shown
in FIGS. 1A and 1B of a parameter editing sidebar.
[0016] FIG. 4 shows an exemplary display at the mobile device shown
in FIGS. 1A and 1B of a visualization of simulation results.
[0017] FIG. 5 shows an exemplary display at the mobile device shown
in FIGS. 1A and 1B of individual bus information.
[0018] FIGS. 6-8 each show an exemplary display at the mobile
device shown in FIGS. 1A and 1B of a summary visualization of N-1
contingency scenarios.
[0019] FIG. 9 shows an exemplary display at the mobile device shown
in FIGS. 1A and 1B of a Simulation Navigator enabling a
visualization of one of a plurality of simulation results.
[0020] FIG. 10 shows the operation of the Simulation Navigator of
FIG. 6 for enabling a visualization and navigation of multiple
simulation results.
[0021] FIGS. 11-13 shows an exemplary display at the mobile device
shown in FIGS. 1A and 1B of different views of an entire
transmission grid, where FIG. 11 shows a zoomed-out overview, FIG.
12 shows a zoomed-out power flow visualization, and FIG. 13 shows a
zoomed-in view of a portion of the power flow visualization of FIG.
12.
DETAILED DESCRIPTION
[0022] The embodiments of this invention provide in one aspect
thereof methods, computer programs and a system for electrical
power grid simulation and reliability analytics, including remote
control and visualization through the use of devices having
preferably some type of graphical user interface.
[0023] More generally the embodiments of this invention enable
simulations of a grid structure to be performed in accordance with
one or more scenarios of interest to a user. A scenario could be
related to a contingency in an electrical power grid, such as
simulating an effect of removing from service one or more grid
components. In other non-limiting examples the scenario could be an
addition of a new grid component, or the substitution of one grid
component for another grid component.
[0024] The embodiments of this invention provide in one aspect
thereof a graphical user interface (GUI) configured to increase the
reliability and efficiency of electrical power grids by enabling
improved, real-time contingency planning. In some exemplary and
non-limiting embodiments the GUI can be embodied in a mobile
device, e.g., in a laptop, or a tablet, or a smart phone, and
therefore allows both immediate response to emergency situations
and convenient contingency planning, regardless of a user's
location. The exemplary embodiments of this invention also provide
for the use of the GUI with a high-speed, high-performance backend
computing system. In one non-limiting embodiment the backend
computing system is configured with a Blue Gene.RTM./Q or similar
supercomputer to accelerate physical simulations of the power grid.
The resulting enhanced convenience and speed provides that improved
power grid reliability and efficiency can be realized by enabling
flexible remote collaboration and by enabling the exploration of
many more contingencies than are possible with conventional
approaches. The improved real-time contingency planning made
possible by the use of this invention allows a power grid operator
to reduce the frequency, severity and duration of unplanned
outages, while also enabling the operator to better optimize system
performance, cost and efficiency.
[0025] FIG. 1A illustrates a high level block diagram of one
non-limiting embodiment of a system 10 that is configured to
implement the embodiments of this invention. The system 10 includes
an electrical power grid simulator program 12A running on a high
performance computing platform 12B. One suitable but non-limiting
embodiment of the computing platform 12B is a Blue Gene.RTM./Q
system that is available from the assignee of this patent
application. In this non-limiting embodiment the system 10 also
includes at least one GUI 14 embodied in a mobile device 16 having
wireless communication capabilities. Interposed between the mobile
device 16 and the electrical power grid simulator 12A/computing
platform 12B is a web server-based communication layer 18. It is
assumed that some type of interface 12C is provided between sensors
and other data generating components of a power grid 15 so that
real-time operation of the power grid 15 can be monitored and
simulated. The interface 12C may also provide connectivity to
various actuators (e.g., switches, variable loads) installed in the
power grid 15 enabling control over certain aspects of the power
grid operations. As is shown in FIG. 1B the instrumented power grid
15 could be referred to for convenience as a `smart grid` 15.
[0026] The computing platform 12B can be implemented using a number
of processor nodes operating in parallel (e.g., in a SIMD
architecture). Scenario parallelism can be implemented using one
task for each scenario to be simulated and a scheduler process that
is responsible for initialization of the individual tasks,
synchronization between tasks, consolidation of results for
communication back to the mobile device 16, calculation of
statistics, etc.
[0027] As considered herein a mobile device 16 can be any type of
device having some computation capability and interface capability
with one or more external networks. The mobile device 16 can be
assumed to include a capability to host the GUI 14. The network
interface capability is preferably based on one or more types of
wireless communication capabilities but can be implemented in whole
or in part via a wired connection (e.g., a cable connected between
the mobile device 16 and a port). Suitable examples of mobile
devices include, but are not limited to, laptop computing devices,
notebook computing devices, tablet computing devices, smartphones
and, in general, any type of computing device having, preferably,
an ability to wirelessly connect (e.g., via radio frequency signals
and/or optical signals) with the web server-based communication
layer 18. The mobile device 16 could be a commercial, off-the-shelf
type of user communication device, such as a tablet, containing the
GUI 14 software as an add-in application program, or it could be a
specialized type of device designed and configured to implement the
embodiments of this invention.
[0028] In any case the device that hosts the GUI 14, such as the
mobile device 16, is assumed to have some minimal functionality
including for example a central processing unit (CPU) or data
processor 20 (e.g., a microprocessor) connected with one or more
computer readable medium(s) that can be embodied as one or more
memories 22, and with at least one type of wireless communication
circuitry 24. In general the mobile device 16 can be assumed to
include some type of user interface (UI) such as a display screen
26 and a user data input 28 such as a keyboard or keypad or a
touch-sensitive surface (possibly part of the display screen 26)
and/or a voice input and recognition system.
[0029] The memory 22 can be any type of memory device or multiple
devices suitable for integration into the device. The memory 22 can
be assumed to store native software 22A needed to operate the
device, such as the mobile device 16, and to also store at least
one application (APP) program or software 22B that is configured to
operate in accordance with the embodiments of this invention. The
at least one application (APP) program or software 22B can be
assumed to include computer program instructions and software
configured to implement the GUI 14 in cooperation with the display
screen 26 and the user data input 28. Hereafter a reference to the
GUI 14 can be assumed to include the GUI software stored in the
memory portion 22B as well as the display 26 and user input 28. The
memory 22 is also assumed to include some type of data storage 22C
to store, for example, downloaded data, to store results of
computations and results of simulations, and to store temporary
variables and related data needed during computation/processing of
the downloaded data.
[0030] The wireless communication circuitry 24 if present can be
based on, for example, a low power, short range, local area
technology such as Bluetooth.TM. or a WiFi-type of technology to
enable communication with at least one access point (AP) 30. In
some cases the wireless communication circuitry 24 will include a
longer range, wider area wireless technology such as a cellular
radio transceiver and related circuitry and software to enable
communication with the least one AP 30. The AP 30 in turn provides
connectivity via one or more networks 32 to the electrical power
grid simulator 12A/computing platform 12B. The electrical power
grid simulator 12A/computing platform 12B could be physically
instantiated at some particular location or it could be virtualized
and reside in a computing cloud 34. The web server-based
communication layer 18 can be assumed to include all or some of the
AP 30 and the one or more networks 32 including any applicable
gateways, domain name servers (DNS) and the like.
[0031] It should be realized that while an exemplary embodiment of
this invention employs the mobile device 16, in other embodiments
the device that hosts the GUI 16 could be any type of user device
such as a desktop computer or terminal, and the interface to the
computing platform 12B could be a wireless interface or a wired
interface using any type of conventional wireless or wired
network(s) using any type of conventional data transmission
protocols. Combinations of various types of networks can also be
used to provide connectivity between the user device that hosts the
GUI 14 and the computing platform 12B. As such it should be kept in
mind that subsequent references to the mobile device 16 should not
be interpreted in a limiting sense as to the type or types of user
devices that can be employed to practice this invention.
[0032] FIG. 1B shows another view of the system 10. In this view
the power grid, or `smart grid` 15, is shown to include various
power generators (e.g., public power plants, wind turbine
generators, solar generators) plus energy storage equipment and
plug-in EV units. The smart grid 15 also includes the transmission
distribution grid per se such as high voltage, medium and low
voltage lines along with transformers and related equipment. The
smart grid 15 includes various sensors and related equipment to
monitor the operation of the distribution grid including
intelligent electronic devices (LEDs), remote terminal units (RTUs)
and supervisory control and data acquisition (SCADA) systems. These
sensors and related equipment can include phase measurement units
(PMUs), phase data concentrators (PDCs) and various `smart`
appliances, meters and the like. These are connected with the
interface 12C via various communication protocols and links
including, for example, the interne, a private digital network
and/or by using signals superimposed on the grid conductors
themselves. The interface 12C can be embodied, for example, as at
least one mass digital storage management (MDSM) unit that is
connected with the electrical power grid simulator 12A/computing
platform 12B. The operation of the electrical power grid simulator
12A/computing platform 12B can be considered to implement a
`virtual grid` whereby monitoring and simulations of the grid 15
can be carried out. The simulations can be based in part on the
actual real time or near real-time data measured and reported by
the various sensors via the interface 12C. The mobile device 16
containing the GUI 14 is bidirectionally connected with the
electrical power grid simulator 12A/computing platform 12B via the
web server-based communication layer 18. In some embodiments the
communication layer 18 could be or could include a private digital
network. In practice there could be many mobile devices 16 in use
at any given time, where the mobile devices 16 could be distributed
over a wide geographical area both within the geographical area of
the grid 15 and external to the grid 15.
[0033] For those embodiments where the grid structure is an
electrical power grid the electrical power grid simulator program
12A is preferably one that can solve a standard load flow problem
for the steady-state sinusoidal voltages and power flows in a
network, resulting from a specified pattern of loads and
generation. The code can be based on principles as described, for
example, in MATPOWER: Steady-State Operations, Planning, and
Analysis Tools for Power Systems Research and Education, Ray Daniel
Zimmerman, Carlos Edmundo Murillo-Sanchez, and Robert John Thomas,
IEEE Transactions on Power Systems, Vol. 26, No. 1, February 2011;
MATPOWER 4.1 User's Manual, Ray D. Zimmerman, Carlos E.
Murillo-Sanchez, Power Systems Engineering Research Center, Dec.
14, 2011; and Power System Load Flow Analysis, Lynn Powell, McGraw
Hill, 2004.
[0034] The power system model of the electrical power grid
simulator program 12A can contain a number of buses connected by
branches in the desired network topology. The buses represent
generators, loads, and/or connection substations, and each branch
represents a transmission line and its associated transformer (such
as a phase-shifting transformer). Since the model is meant to
represent the transmission system, the loads can be represented as
substations, and the distribution system attached to the output of
the substations could be in some cases a level of detail not
considered by the model.
[0035] Voltages are modeled as a complex quantity, with a voltage
magnitude and phase angle. Power is a complex variable with the
real part representing active power and the imaginary part
representing reactive power.
[0036] There can be three kinds of buses considered in the model: a
PV bus, a PQ, bus and a slack bus. In a PV bus, typically used to
model generators, the active power and voltage magnitude are
specified, and the reactive power and voltage angle are to be
determined by simulation. In a PQ bus, typically used to model
loads, the active power and reactive power are specified, and the
voltage magnitude and angle are to be determined by simulation. In
order to avoid over-specifying the problem, one generator can be
modeled as a slack bus (and also serves as a voltage-angle
reference). In this bus the voltage magnitude and angle are
specified, and active and reactive power are to be determined by
simulation. Buses can be grouped in the input/output data of the
simulator, so that, for example, a particular bus can contain
several generators and loads.
[0037] The branches can use a .pi. transmission-line model, with
parameters of complex impedance, total charging capacitance, and
the tap ratio and phase shift of an ideal phase-shifting
transformer attached to the from end of the branch.
[0038] The AC nodal power balance for the network can be expressed
as a complex matrix nonlinear system of equations. This is
separated into real and reactive components, yielding a system of
nonlinear equations that are solved by numerical techniques such as
Newton's method.
[0039] The electrical power grid simulator program 12A can operate
in a single-step mode, in which the initial known values are
specified and the unknowns are solved for, giving complete
steady-state information on bus voltage magnitude and angle,
generation and load active and reactive power injections at each
bus, and active and reactive power flow and loss for each
branch.
[0040] Alternately the simulator can perform multistep simulations
in which certain resulting values are compared to allowable bounds,
and out-of-bounds quantities are assumed to lead to component
failure or operation mode changes. For example, excessive reactive
power demand on a generator can result in the generator going off
line, or the generator producing a fixed amount of active and
reactive power (behaving like a PQ bus rather than a PV bus).
Excessive power flow on a branch can cause the branch to trip and
go out of service. After adjusting the model to reflect any
failures or operation mode changes, the simulation can be run
again, and the checking process is repeated. By continuing to
iterate in this manner with changing loads and generation over
time, studies of cascading failures may be performed.
[0041] It should be appreciated that the examples of the
embodiments of this invention are not limited for use with any
particular types of electrical power grid simulator programs,
computing platforms, mobile and other types of user devices and
communication buses and links. The embodiments shown in FIGS. 1A
and 1B and described above are provided just as non-limiting
examples of suitable technological contexts in which the
embodiments of this invention can be realized. For example the
simulation could be transient or dynamic in nature as opposed to
steady state.
[0042] Because of the large amount of information required to
prepare an initial scenario (case file) for the power grid
simulator 12A it is preferred that these are set up a priori on a
file system of the computing platform 12B. The GUI 14, however,
does permit modification of existing scenarios or automatic
generation of new scenarios.
[0043] An initial welcome screen presented by the GUI 14 allows the
user to choose whether single or multiple starting scenarios are to
be used. A single scenario to be used is chosen from a list of
available scenarios. Multiple scenarios may either be chosen from
available prepared sets of multiple scenarios, or they may be
automatically generated. To automatically generate multiple
scenarios the user picks an available starting scenario, the
desired number of scenarios to be generated, and one of any
available rules for generating multiple scenarios. For example, a
rule could be to start with an initial scenario, and for each
successive scenario, increase the active power demand on every load
by 1%, such as might be experienced as air conditioners
progressively come on line during a heat wave. Another rule can be
to create a progression of generation increments or decrements.
Still another rule could, for example, introduce random changes
with various statistical distributions to simulate, for example,
the variable injection into the power grid of renewable generation
sources such as solar or wind power generators.
[0044] Yet another rule for creating multiple scenarios is related
to performing a contingency analysis for either generators or power
distribution branches of the power grid 15. For an N-1 contingency
analysis, N scenarios are generated, where N is the number of
generators (and/or branches), and each scenario (contingency being
modeled) has a different one of the generators (and/or branches)
disabled. For an N-k contingency, each of the binomial coefficient
N choose k scenarios has k generators (and/or branches)
disabled.
[0045] More generally the embodiments of this invention enables an
N-k contingency analysis simulation to be performed and the results
visualized, where k is equal to zero, 1 or greater, where binomial
coefficient N choose k scenarios are generated, and each scenario
has k generators and/or branches disabled. For the case where k=0
the simulation may simply enable the grid operation/status to be
visualized without introducing any failure modes or contingencies
in the grid structure.
[0046] After setting up the initial scenario(s), the user selects
whether a one-step or a multi-step simulation by the power grid
simulator 12A is desired. A one-step simulation computes the
resulting state of the power grid 15 for each of the single or
multiple initial scenarios. A multi-step simulation can begin in
the same manner, but then checks for out-of-bounds values, modifies
the power grid model to reflect unit failures, and re-runs the
simulation. This process can iterate until a user-selected maximum
number of iterations is reached, or until there are no further
significant changes.
[0047] In one embodiment the power grid simulator 12A assumes,
simply for convenience, that the power flows are in a steady state.
However in other embodiments the power grid simulator 12A can
operate equally well with a dynamical model.
[0048] The model resident at the computing platform 12A inputs
various physical quantities that are measured from the power grid
15 via the interface 12C and uses these to calculate the physical
quantities required to evaluate the overall `health` of the grid
15, including for example when a given transmission line is close
to or above safety tolerance levels. This information can be used
to identify when various components of the grid 15 are likely to
fail and to take steps to remediate the problem. Additionally, this
information can be used to evaluate the power efficiency of the
grid 15 and to adjust production to obtain increased
efficiency.
[0049] For example, it is typically required that power utilities
perform some type of N-1 contingency analysis used to answer the
question, e.g., "What would happen if any one component of the
system were to fail?" However, growing concern over the reliability
of power grids has led to a call for N-2 and even N-k contingency
testing where k>2. For a system with N components, N-1
contingency analysis requires N simulations; but for N-2, N(N+1)/2
simulations are required and for N-k there is a combinatorial
expansion of the required number of simulations.
[0050] Use of the Blue Gene.RTM./Q or similar supercomputer as the
high performance computing platform 12B enables handling
orders-of-magnitude more simulations than are currently possible,
and allows an expansion beyond N-1 contingency analysis to increase
overall system reliability and efficiency.
[0051] For example, reference can be made to FIG. 1C that shows an
example of N-k contingency hardware requirements, in this example
an estimated number of Blue Gene/Q cores required to run an N-k
contingency simulation in one minute, versus k. In general the
needed computing power of the platform 12B is that required to
complete a desired simulation in an acceptable amount of time
(e.g., 1 minute for "real-time", 1 hour for "near real-time",
etc.)
[0052] However, it should be appreciated that the embodiments of
this invention do not require any specific type or class of
computing platform 12B.
[0053] Further in this regard it should be realized that in some
embodiments all or at least some of the computational and data
storage and handling functionality of the computing platform 12B
could be incorporated and integrated into the user device 16, and
that in certain such embodiments the user device 16 could be
interfaced to receive the outputs from the various grid 15 sensors
via the interface 12C and the web server-based communication layer
18.
[0054] The mobile GUI 14 for contingency analysis provides
convenience and ease of use, and renders complex information
quickly and accurately. The GUI 14 is used to visualize the current
state of the grid 15, to remotely initiate simulations on high
performance computing platform 12B and to visualize the results of
the simulations.
[0055] The GUI 14 can also be used in some embodiments to remotely
control operations of the grid 15 and to remotely initiate
remediation and other types of actions.
[0056] After the initial selection of a single starting scenario by
the user of the mobile device 16 the GUI 14 displays a
visualization of the system topology, such as the one shown by
example in FIG. 2. The power grid 15 is laid out geographically on
top of a map of the relevant area. The nodes of the power grid 15
are laid out according to their actual geographical locations
relative to the map. By using standard mobile device 12 touchscreen
finger movements the user can pan and zoom in or out, to facilitate
broad overviews or detailed manipulations of a small part of a
large network.
[0057] In one non-limiting example, and as is common in the power
generation and distribution industry, circular icons represent
generator buses, triangular icons represent load buses, and square
icons represent buses that contain both generation and load. The
lines between the buses represent the branches. In other
embodiments different representations, indicia, indicators and
icons can be used to represent these same and other parameters. In
this invention tapping on one of the square bus icons on the GUI 14
can activate a popup display region with an icon for each generator
and each load in the corresponding bus.
[0058] This operation can be accomplished at least in part by the
mobile device 16 sending information descriptive of the bus icon
selected by the user (e.g., at least geographical coordinates) to
the computing platform 12B, the computing platform 12B returning
the applicable bus-related information as obtained from the grid
sensors via the interface 12C, and the GUI 14 formatting and
rendering the returned information on the display screen 26.
[0059] If it is desired to modify the parameters of any of the
generators or loads, tapping on them opens a parameter
modification/editing sidebar such as the one shown in FIG. 3.
Modifiable values can then be changed by moving the sliders, such
as by the user sliding a finger across the displayed slider. In the
sidebar color coding can be used to indicate out-of-tolerance and
in-tolerance conditions.
[0060] While this embodiment can be used to modify parameters for a
simulation, in other embodiments the mobile device 16 can transmit
the changed parameter(s) to the computing platform 12B that in turn
can relay the changed parameters to the grid structure 15 for input
to one or more of the applicable grid actuators. Alternatively the
mobile device 16 can transmit the changed parameter(s) directly to
a receiver associated with the grid structure 15 for input to the
one or more applicable grid actuators.
[0061] Thus, an aspect of this invention provides an ability send
in response to a user input a command to the grid structure 15 in
order to change a state of at least one grid structure actuator.
This embodiment can imply the presence of any needed security and
authorization layers in the communication stream between the mobile
device 16 and the computing platform/grid.
[0062] In the single scenario simulation once the initial
scenario(s) are selected or generated using the GUI 14 in
combination with the electrical power grid simulator program 12A
running on the high performance computing platform 12B and if
desired modified, the user taps a button that begins the simulation
at the simulator program 12A. An example of the resulting computed
system-state visualization for a particular simulation that is
returned to the mobile device 16 is shown in FIG. 4.
[0063] In the non-limiting example that is shown more particularly
in FIG. 9 the direction of power flow in the branches is indicated
by arrows. The branches can be colored according to their
utilization: e.g., blue for nominal (e.g., up to 80%), magenta for
heavy (between 80% and 100%), and red when the maximum permissible
utilization is exceeded. The discs around the buses can be colored
and also sized according to voltage magnitude (Vm), where the
larger the disk the more Vm differs from the nominal value. A blue
color of a certain disc indicates that Vm is within tolerance,
magenta indicates near the maximum or minimum allowable voltage,
and red indicates out-of-tolerance. Note that the specific colors,
icons, line types, etc., used in this non-limiting example are not
limiting to the scope of the invention, as others could as well be
used.
[0064] Detailed information for each bus or branch can be obtained
by tapping on its icon as is shown in FIG. 5 for Bus 54. The
tapping action results, in cooperation with the electrical power
grid simulator program 12A running on the high performance
computing platform 12B, in a sidebar being displayed for Bus 54
with graphical and numerical displays of the associated quantities.
In FIG. 5 the quantities displayed for the selected buses are: Pg
and Qg, the active and reactive power generation; Pd and Qd, the
active and reactive power demand; Vm, the voltage magnitude; and
Va, the voltage angle. Note that the specific data quantities
displayed in this one embodiment of the invention are not meant to
be limiting to the invention.
[0065] The GUI 14 provides a means of summarizing the results of
multiple power flow simulations in various selectable ways and
visualizing the resulting summary. FIGS. 6-9 show different
summaries of the same set of N-1 contingency scenario simulations,
in this case an N-1 contingency analysis on the branches. By
selecting the Min, Avg, or Max buttons with either of the Branches
or Buses buttons, the visualization can be made to show the Min,
Avg, or Max branch utilization over all the scenarios, as well as
the Min, Avg, or Max voltage magnitude at the buses over all the
scenarios. The selection of Min, Avg, or Max can be independently
made for branches and buses.
[0066] With respect to a non-limiting example that involves
cascading failure simulations, and in the case of a multiple
starting scenario, multi-step simulation, there is derived a
desired type of multi-dimensional visual representation of the
results of the simulation of at least one scenario. The visual
representation can take any suitable form, such as a
two-dimensional Cartesian graph or matrix, a polar coordinate
graph, a pie chart, or a three-dimensional plot as but a few
non-limiting examples. In the non-limiting case of the
two-dimensional matrix of results: for each initial scenario there
can be a sequence of simulations in time. The time can be linear
time. In another example the time axis could be graduated by
changes of state in the simulated system and could thus be
considered as being non-linear. In some embodiments a time axis may
be inferred. In some embodiments a time axis may not be present but
some other parameter can be represented. For example, for a wind
generation case one axis could be temperature or demand and the
other axis could be wind speed. Further by example, for a solar
generation case one axis could be temperature or demand and the
other axis could be cloud cover.
[0067] These and other types of scenarios can be represented by a
Simulation Navigator box 40 shown in the lower left corner of FIG.
9, where in this non-limiting example each square (which may be
generally referred to as an `indicator`) represents or indicates
the result of an individual simulation plotted over power (vertical
axis) and steps (horizontal axis). The horizontal axis could also
represent time. The resulting display can be viewed as a
visualization of risk. Tapping on any one of the squares
(indicators) in the Simulation Navigator box causes the
visualization of that particular corresponding simulation result to
be displayed on the GUI 14. This can occur by the user device 16
querying the simulation program 12A for the results of the
identified simulation (if the simulation results have not been
already stored in the user device 16). The results can be displayed
using the sidebar 42 shown in the upper right corner of the GUI
screen. It is also possible to view aggregated statistics over
multiple results, such as minimum, average, and maximum asset
utilization, or percentage of values out of bounds.
[0068] Note that in accordance with certain preferred embodiments
of this invention each square (indicator) in the Simulation
Navigator box can represent aggregate results of two or more
simulations such as, by example, the average value of the results
of ten simulations or the mean value of the results of 100
simulations. Those persons skilled in the art will recognize that
the ability to represent and visualize this type of data is very
advantageous as compared to conventional techniques for viewing a
result of a contingency simulation, such as by simply reviewing
charts, tables and columns of numbers.
[0069] As is shown in FIG. 10, if the user slides a finger (or any
appropriate pointing device) across a number of indicators the
Simulation Navigator 40 initiates an animated slide-show of the
chosen results to be viewed. This can be used to provide a
visualization to the user of the progression of cascading
failures.
[0070] It is also within the scope of these embodiments to respond
to the user tapping on one of the indicators of the Simulation
Navigator 40 by starting or launching an animation that visualizes
the results of some number of underlying simulations. In this case
time can be an implicit dimension. Cascading simulation failure
results can thus be visualized. The underlying simulation could
have been pre-computed and stored or some or all of them can be
computed on the fly.
[0071] In the exemplary simulation displayed in FIG. 10 the grid
experiences increasing failures with time (e.g., 85%, 58%, 10%
within tolerance). Eventually a stable state is reached as shown in
the rightmost depiction in which most of the branches are out of
service (e.g., rendered as heavy black lines), except for two grid
`islands` that continue to operate due to, for example, a good
match between local generation and demand.
[0072] Note that although the squares that form the display of the
Simulation Navigator 40 could be shown with a color gradient, the
colors, gradients, shapes, and layout are not meant to be limiting.
For example, the squares could instead by circles, or the layout
could be scrollable, stacked, or have some other configuration.
[0073] FIGS. 11-13 show another example of a grid visualization
example that is made possible with the GUI 14 running on the mobile
device 16. In this grid visualization example there are several
thousand buses representing a particular transmission grid under
peak-load conditions. FIG. 11 shows the overall (zoomed-out) grid
topology and, as with the other visualizations, the layout of the
nodes is chosen for topological clarity and may not correspond to
actual geographic locations. FIG. 12 depicts a power-flow
visualization of the same grid and FIG. 13 is a zoomed-in version
of FIG. 12 showing just a portion of the buses, including those
with the highest, possibly out-of-range power usage.
[0074] In FIGS. 11-12 color-coded regions can be used to represent
under-voltage or over-voltage events so that such events stand out
clearly. Zooming in on areas of interest (as in FIG. 13) allows
more detail to be viewed, down to the level of specific localized
numerical information by tapping on individual buses or
branches.
[0075] In accordance with one aspect of this invention the GUI 14
can allow the user to interact with simulations that are currently
running. In one embodiment the user can visualize real-time grid
data or evolving simulation data and interact with the simulation,
requesting more detail as needed based on the evolution of the
real-time visualization. For example, if during the visualization
of a steady-state power-flow simulation the user observes what
appears to be an unusual situation the user can click on a
particular point on the grid to bring up a transient waveform
analysis of that point. This avoids computing the more expensive
transient simulation unless it is needed, speeding up response and
more efficiently using computing resources.
[0076] In another embodiment the user can take a real-time
`snapshot` of the status of the grid and then use that grid data as
the starting point for a contingency analysis simulation.
[0077] In yet another embodiment the user can have a long-running
simulation running on the computing platform 12B and be receiving
periodic updates of the visualization as the simulation results
become available. In this case the user can interact with the
simulation by modifying the future path of the simulation based on
the visualization. For example, in the case of a cascading failure
simulation a certain path may be observed that is of no interest to
the user, and the user can instruct the simulator to prune the
simulation scenario space to concentrate available computing power
on the remaining interesting paths, to make them complete more
quickly.
[0078] It can be appreciated that when simulating certain examples
of considerable size and complexity the ability of the GUI 14, in
combination with the electrical power grid simulator program 12A
running on the high performance computing platform 12B, can render
a visualization that conveys at-a-glance the overall health of the
grid. This type of visualization would not otherwise be accessible
to a power grid operator or other user; instead the user would need
to review this type of data in the context of large printed tables
with numerical values, making pattern detection, interpretation and
diagnosis extremely difficult. One significant advantage of the
visualization made possible by the use of the embodiments of this
invention is that a wide scope can be made visible without
sacrificing the ability to also view detailed, lower-level data
such as is currently presented as tables of numbers. This can be
accomplished by simply by clicking, touching and/or zooming in on
the area of interest. FIG. 12 represents one example of this type
of visualization that is made possible by the use of this
invention.
[0079] As should be apparent the embodiments of this invention
provide for a visualization on the GUI 14 to be comprised of
graphical-type images as well as alphanumeric-type information
expressed in any convenient format such as in a table for further
specifying a result or a partial result of a simulation or
simulations.
[0080] Another aspect of the embodiments of this invention is that
the user is enabled to select a portion of a displayed grid (e.g.,
a power distribution grid). The mobile device 16 sends to the
computing platform information that describes the selected portion
of the grid, e.g., bounding geographic coordinates, and a type of
simulation to be performed. In response the electrical power grid
simulator program 12A then performs the desired type of simulation
within the user-selected portion of the grid. That is, only a
portion of the overall grid that is of interest to the user can be
selected and simulated.
[0081] In an example of an information flow made possible by the
use of the system 10 one can consider the following steps.
[0082] 1. The user selects the desired simulation scenario using
the GUI 14. The mobile device 16 then sends a request to a server
associated with the computing platform 1213 for the associated
simulator input file.
[0083] 2. The simulation case files can be stored on the file
system (e.g., a parallel file system such as one known as General
Parallel File System (GPFS.TM.)). The GPFS.TM. is an example of a
high-performance shared-disk clustered file system and can be
attached to the computing platform 12B. The server copies the
correct file from the file system.
[0084] 3. The server then returns the location of the input file to
the mobile device 16.
[0085] 4. The mobile device 16 downloads the input file from the
server, renders the grid visualization, and displays it to the
user.
[0086] 5. The user may make changes to the simulation scenario
using the GUI 14. The mobile device 16 then makes changes to the
input file based on the user's input. The user can also specify the
kind of simulation that is to be run.
[0087] 6. The mobile device 16 sends any changes, as well as the
kind of simulation desired, to the server.
[0088] 7. The server sends the changed input to file system.
[0089] 8. The server runs code such as a script or an application
on the computing platform 12B that dispatches a job for the
requested simulation to the compute nodes of the computing platform
12B, which then run the simulation and writes the output file to
the file system.
[0090] 9. The server monitors the file system to determine when the
output file is ready. Once ready, the server copies the file from
file system to its own file system.
[0091] 10. The server informs the mobile device 16 where the output
file is on the server.
[0092] 11. The mobile device 16 downloads the output file from the
server.
[0093] 12. The mobile device 16 renders the visualization from the
output file and displays the results to the user.
[0094] In general a grid can be comprised of a transmission grid or
grids and/or a distribution grid or grids, and all of the attendant
systems and subsystems thereof known to those skilled in the art.
Sensors can be configured at grid elements (or a subset of
elements) to be modeled. An apparatus is configured for collecting
sensor data to a central or distributed computing facility. The
computing facility includes at least a computer program configured
to model the behavior of the transmission grid based on a known or
an estimated topology of the grid and components of the grid; on a
known, measured or estimated power production (e.g., from public
power plants, private solar panels, or wind farms, etc.); and on a
known, measured or estimated power demand. The computer program can
provide real-time information about the transmission grid system to
at least one user device, such as a tablet-based computing device
or a laptop computing device or any type of computing device
capable of hosting the GUI 14. The information transferred can be
conveyed over one or more wireless links alone or in combination
with one or more wired links. The combination of the computer
program at the computing facility and a computer program installed
in the user device enables a user to initiate and interact with a
transmission grid simulation to dynamically modify the grid
structure both speculatively (in a "what-if" mode to determine and
visualize the impact of hypothetical changes to the grid) and
on-demand (in a "command" mode to modify the actual operational
parameters of the grid, e.g., increasing supply or shutting down a
transmission line.)
[0095] As should be appreciated there has been described a system
and method for modeling, simulating and/or visualizing the
operation and flow on a grid of arbitrarily interconnected nodes
comprised of a modeling module, a simulation system, a user I/O
device, a grid input module, a grid output module, a simulation
analysis module and possibly a grid control device. The simulation
module can be configured to simulate as non-limiting examples power
grids, communication grids, water distribution grids, electric
grids on integrated circuits, etc., as well other types of complex
multi-dimensional structures and systems and grids having nodes
that are interconnected by pathways, branches and conduits that can
convey energy, fluid, radiation, motor vehicles (a network of
roadways forming a transportation grid), aircraft (a
three-dimensional air traffic control grid), etc. The system 10
includes a computer system 12B running a program 12A to simulate a
model that could be in some embodiments a steady state or a dynamic
power flow simulation, contingency analysis simulation, cascading
failure simulation, etc.
[0096] The user I/O device embodied in, for example, the mobile
device 16 includes a visualizer for displaying a graphical
representation of the state of the grid or grid simulation at past,
current or future times, and can include a user input device
possibly with a touch enabled screen to direct and control the
operation of the simulation including setup, run time and
analysis.
[0097] The grid input module provides a means to read pre-stored
grid data from a data base and/or to input real-time sensor data
from an actual physical grid. The grid output module includes a
storage device for simulation output and analysis by the simulation
analysis module. The grid control device may be used to control the
operation of an actual physical grid based on the results of the
output from the analysis module and/or the user IO device.
[0098] In accordance with this invention the user can interact with
simulations that are currently running (enabled by high speed
computation, massive parallelism and flexible user interface).
[0099] The computer system could be implemented as a
single-processor computer, as a multi-processor computer, or as a
supercomputer, for example Blue Gene.RTM./Q or similar
supercomputer. In some embodiments the computer system could be
integrated in whole or in part in the user device 16.
[0100] The visualization presented on the user I/O device could
contain, for example, one or more of visualization of power flow
through the branches of the grid, which may include active and
reactive power flows, phase angles, and maximum, average, or
minimum values over a variety of scenarios, and/or any other grid
characteristics that are known to those skilled in the art.
[0101] The visualization of generation and demand at the nodes of
the grid can include, for example, one or more of active and
reactive generation and demand, phase angles, and maximum, average,
or minimum values over a variety of scenarios, and/or any other
grid characteristics that are known to those skilled in the
art.
[0102] The visualization presented on the user I/O device can
provide a user with knowledge of multiple (e.g., thousands of)
contingencies of a complex system.
[0103] The visualization presented on the user I/O device can
provide a user with various representations such as maps showing a
result of random or pseudo-random perturbations of the grid
structure.
[0104] The initial user setup can include selection of initial
system states for the simulation, selection of a schedule of system
condition variations whose effect on the grid is to be simulated,
which may include one or more of a schedule of load variations, a
schedule of generation variations, a schedule of load, generation,
and/or branch failures. The selections may be performed by the user
by selecting individual nodes or branches to modify, selecting
regions that include multiple nodes or branches to modify, for
example by `lassoing` them on the display screen 26. The initial
selection can include as starting data some stored historic grid
data or it can include real-time grid data captured by the grid
sensors prior to the start of the simulation, and possibly captured
as well during the simulation. In some embodiments a live data feed
from the grid sensors can be employed and the simulation can use
periodic snapshots of the grid data in substantially real-time or
near real-time. The initial selection can also include the user
selectively specifying certain scenarios via the GUI 14, such as
adding an element to the grid structure (e.g., adding a new
generator at a certain location within the grid structure) or
replacing an existing element with another element (e.g., replacing
a solar generator with a wind generator). The embodiments of this
invention enable various grid structure characteristics to be
visualized including as non-limiting examples one or more of grid
integrity, localized grid operational status and a summary of the
overall operational status of the grid structure. The embodiments
of this invention can thus be seen to find utility as a planning
tool.
[0105] The storage device associated with the computing platform
12B may be a high-performance parallel file system. A non-limiting
example includes GPFS.TM..
[0106] The embodiments of this invention can be considered in some
aspects thereof as providing a failure map or a risk map or a heat
map of failures and potential failures in the grid structure.
[0107] The embodiments of this invention also encompass a
`differential` visualization mode of operation where what is
displayed to the user represents a difference between two (or more)
simulation results that represent a difference between two (or
more) grid states. For example, one simulation result may be a
historical (stored) simulation result while another simulation
result may be a current simulation result. The results are compared
and what is visualized is the difference between the simulation
results. In another example one simulation result may have as a
simulation scenario an ambient temperature of 72.degree. F. while a
second simulation result may assume an ambient temperature of
76.degree. F. This mode of operation enables the user to readily
compare a difference between the two or more grid states and the
effect on the operational status of the grid structure. A fixed or
an adjustable threshold value may be used to filter out difference
values resulting from noise events or random fluctuations in some
grid parameter(s) thereby causing only meaningful grid simulation
result differences to be shown to the user.
[0108] As will be appreciated by one skilled in the art, aspects of
the present invention may be embodied as a system, method or
computer program product. Accordingly, aspects of the present
invention may take the form of an entirely hardware embodiment, an
entirely software embodiment (including firmware, resident
software, micro-code, etc.) or an embodiment combining software and
hardware aspects that may all generally be referred to herein as a
`circuit`, a `module` or a `system`. Furthermore, aspects of the
present invention may take the form of a computer program product
embodied in one or more computer readable medium(s) having computer
readable program code embodied thereon.
[0109] Any combination of one or more computer readable medium(s)
may be utilized. The computer readable medium may be a computer
readable signal medium or a computer readable storage medium. A
computer readable storage medium maybe, for example, but not
limited to, an electronic, magnetic, optical, electromagnetic,
infrared, or semiconductor system, apparatus, or device, or any
suitable combination of the foregoing. More specific examples (a
non-exhaustive list) of the computer readable storage medium would
include the following: an electrical connection having one or more
wires, a portable computer diskette, a hard disk, a random access
memory (RAM), a read-only memory (ROM), an erasable programmable
read-only memory (EPROM or Flash memory), an optical fiber, a
portable compact disc read-only memory (CD-ROM), an optical storage
device, a magnetic storage device, or any suitable combination of
the foregoing. In the context of this document, a computer readable
storage medium may be any tangible medium that can contain, or
store a program for use by or in connection with an instruction
execution system, apparatus, or device.
[0110] A computer readable signal medium may include a propagated
data signal with computer readable program code embodied therein,
for example, in baseband or as part of a carrier wave. Such a
propagated signal may take any of a variety of forms, including,
but not limited to, electro-magnetic, optical, or any suitable
combination thereof. A computer readable signal medium may be any
computer readable medium that is not a computer readable storage
medium and that can communicate, propagate, or transport a program
for use by or in connection with an instruction execution system,
apparatus, or device.
[0111] Program code embodied on a computer readable medium may be
transmitted using any appropriate medium, including but not limited
to wireless, wireline, optical fiber cable, RF, etc., or any
suitable combination of the foregoing.
[0112] Computer program code for carrying out operations for
aspects of the present invention may be written in any combination
of one or more programming languages, including an object oriented
programming language such as Java, Smalltalk, C++ or the like and
conventional procedural programming languages, such as the "C"
programming language or similar programming languages. The program
code may execute entirely on a single local computer, partly on the
local computer, as a stand-alone software package, partly on the
local computer and partly on a remote computer or entirely on the
remote computer or server. In the latter scenario, the remote
computer may be connected to the local computer through any type of
network, including a LAN or a WAN, or the connection may be made to
an external computer (for example, through the Internet using an
Internet Service Provider).
[0113] Aspects of the present invention are described with
reference to diagrams of methods, apparatus (systems) and computer
program products according to embodiments of the invention. It will
be understood that any methods can be implemented by computer
program instructions. These computer program instructions may be
provided to a processor of a general purpose computer, special
purpose computer, or other programmable data processing apparatus
to produce a machine, such that the instructions, which execute via
the processor of the computer or other programmable data processing
apparatus, create means for implementing the specified
functions/acts.
[0114] These computer program instructions may also be stored in a
computer readable medium that can direct a computer, other
programmable data processing apparatus, or other devices to
function in a particular manner, such that the instructions stored
in the computer readable medium produce an article of manufacture
including instructions which implement the specified
function/act.
[0115] The computer program instructions may also be loaded onto a
computer, other programmable data processing apparatus, or other
devices to cause a series of operational steps to be performed on
the computer, other programmable apparatus or other devices to
produce a computer implemented process such that the instructions
which execute on the computer or other programmable apparatus
provide processes for implementing the specified
functions/acts.
[0116] The block diagrams in the Figures illustrate the
architecture, functionality, and operation of possible
implementations of systems, methods and computer program products
according to various embodiments of the present invention. In this
regard certain blocks may represent a module, segment, or portion
of code, which comprises one or more executable instructions for
implementing the specified logical function(s). It should also be
noted that, in some alternative implementations, the functions
noted in the block may occur out of the order noted in the figures.
For example, two blocks shown in succession may, in fact, be
executed substantially concurrently, or the blocks may sometimes be
executed in the reverse order, depending upon the functionality
involved. It will also be noted that each block can be implemented
by special purpose hardware-based systems that perform the
specified functions or acts, or combinations of special purpose
hardware and computer instructions.
[0117] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0118] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
act for performing the function in combination with other claimed
elements as specifically claimed. The description of the present
invention has been presented for purposes of illustration and
description, but is not intended to be exhaustive or limited to the
invention in the form disclosed. Many modifications and variations
will be apparent to those of ordinary skill in the art without
departing from the scope and spirit of the invention. The
embodiment was chosen and described in order to best explain the
principles of the invention and the practical application, and to
enable others of ordinary skill in the art to understand the
invention for various embodiments with various modifications as are
suited to the particular use contemplated. As such, various
modifications and adaptations may become apparent to those skilled
in the relevant arts in view of the foregoing description, when
read in conjunction with the accompanying drawings and the appended
claims. As but a few examples, those skilled in the art may
contemplate the use of other similar or equivalent computer
systems, user devices, grid structures and types of grid
structures, communication links, interface components and the like.
However, all such and similar modifications of the teachings of
this invention will still fall within the scope of this
invention.
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