U.S. patent application number 14/382013 was filed with the patent office on 2015-03-05 for method and system for advising operator action.
The applicant listed for this patent is Nuovo Pignone srl. Invention is credited to Osama Naim Ashour, Alessandro Betti, David Bianucci, Alberto Ceccherini, Riccardo Crociani, Abdurrahman Abdalah Khalidi, Antonio Pumo, Arul Saravanapriyan.
Application Number | 20150066418 14/382013 |
Document ID | / |
Family ID | 46051732 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150066418 |
Kind Code |
A1 |
Ceccherini; Alberto ; et
al. |
March 5, 2015 |
METHOD AND SYSTEM FOR ADVISING OPERATOR ACTION
Abstract
A system and computer-implemented method for monitoring and
diagnosing anomalies in a wheel-space of a gas turbine is
implemented using a computer device coupled to a user interface and
a memory device and includes storing a plurality rule sets in the
memory device, the rule sets relative to the wheel-space, the rule
sets including at least one rule expressed as a relational
expression of a real-time data output relative to a real-time data
input, the relational expression being specific to a temperature of
the wheel-space. The method also includes receiving real-time and
historical data inputs from a condition monitoring system
associated with the gas turbine, the data inputs relating to
sources providing heat to the wheel-space and estimating a
wheel-space temperature value using the inputs relating to a
temperature of the wheel-space.
Inventors: |
Ceccherini; Alberto;
(Florence, IT) ; Khalidi; Abdurrahman Abdalah;
(Doha, QA) ; Saravanapriyan; Arul; (Doha, QA)
; Bianucci; David; (Florence, IT) ; Pumo;
Antonio; (Florence, IT) ; Betti; Alessandro;
(Florence, IT) ; Crociani; Riccardo; (Florence,
IT) ; Ashour; Osama Naim; (Doha, QA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nuovo Pignone srl |
Florence |
|
IT |
|
|
Family ID: |
46051732 |
Appl. No.: |
14/382013 |
Filed: |
March 3, 2013 |
PCT Filed: |
March 3, 2013 |
PCT NO: |
PCT/EP2013/054157 |
371 Date: |
August 29, 2014 |
Current U.S.
Class: |
702/130 |
Current CPC
Class: |
G05B 11/06 20130101;
F05D 2260/80 20130101; H04L 67/10 20130101; F04B 51/00 20130101;
G05B 23/0218 20130101; G01L 3/10 20130101; G05B 23/0216 20130101;
F02C 7/00 20130101; G01K 13/00 20130101; F01D 21/003 20130101; G05B
23/0245 20130101; G05B 23/0283 20130101; G01M 15/14 20130101 |
Class at
Publication: |
702/130 |
International
Class: |
G01M 15/14 20060101
G01M015/14; G01K 13/00 20060101 G01K013/00; F01D 21/00 20060101
F01D021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2012 |
IT |
CO2012A00008 |
Claims
1. A computer-implemented method for monitoring and diagnosing
anomalies in a wheel-space of a gas turbine, the method implemented
using a computer device coupled to a user interface and a memory
device, the method comprising: storing a plurality of rule sets in
a memory device, the rule sets relative to the wheel-space, the
rule sets comprising at least one rule expressed as a relational
expression of a real-time data output relative to a real-time data
input, the relational expression being specific to a temperature of
the wheel-space; receiving real-time and historical data inputs
from a condition monitoring system associated with the gas turbine,
the data inputs relating to sources providing heat to the
wheel-space; and estimating a wheel-space temperature value using
the inputs relating to a temperature of the wheel-space.
2. The method of claim 1, further comprising: comparing the
estimated wheel-space temperature to an actual measured wheel-space
temperature; and generating an advisory message using the
comparison, the advisory message comprising troubleshooting
activities relating to the wheel-space temperature.
3. The method of claim 1, further comprising receiving inputs
representative of heat contained in at least one of hot gas from a
combustion process of the gas turbine, bleed cooling air from an
axial compressor of the gas turbine, and rotor windage effects.
4. The method of claim 1, further comprising setting an initial
estimated baseline for the wheel-space temperature is equal to a
temperature of the axial compressor bleed cooling air compensated
using at least one of a temperature of hot gas from the combustion
process and rotor windage effects.
5. The method of claim 1, further comprising determining the
estimated wheel-space temperature online using a polytropic
efficiency of the axial compressor and the axial compressor bleed
cooling air temperature.
6. A wheel-space monitoring and diagnostic system for a gas turbine
comprising an axial compressor and a low pressure turbine in flow
communication, said wheel-space monitoring and diagnostic system
comprising: a wheel-space temperature rule set, the rule set
comprising a relational expression of a real-time data output
relative to a real-time data input, the relational expression being
specific to inputs relating to sources of heat in the
wheel-space.
7. The system of claim 6, wherein said rule set is configured to
determine an estimated wheel-space temperature value using the
inputs relating to sources of heat in the wheel-space.
8. The system of claim 6, wherein said rule set is configured to
receive inputs representative of heat contained in at least one of
hot gas from the combustion process, axial compressor bleed cooling
air, and rotor windage effects.
9. The system of claim 6, wherein an initial estimated baseline for
the wheel-space temperature is equal to a temperature of the axial
compressor bleed cooling air compensated using at least one of a
temperature of hot gas from the combustion process and rotor
windage effects.
10. The system of claim 6, wherein the estimated wheel-space
temperature is determined online using a polytropic efficiency of
the axial compressor and the axial compressor bleed cooling air
temperature.
Description
FIELD OF THE INVENTION
[0001] This description relates to generally to
mechanical/electrical equipment operations, monitoring and
diagnostics, and more specifically, to systems and methods for
automatically advising operators of anomalous behavior of
machinery.
BACKGROUND OF THE INVENTION
[0002] Monitoring machinery health and alerting operators to
anomalous machinery conditions is an important part of operating
one or a fleet of machines. Specifically, monitoring wheel-space
temperatures is important to health monitoring of gas turbines.
There is currently no known monitoring system for online estimation
of this temperature, and only the measured temperature is
monitored. By not comparing the measured value to an expected
value, the dynamic baseline and physical insight to define alarm
thresholds are unknown. Without this calculation, only static
thresholds based on constant deviation from preset values is
available. Further, troubleshooting is hindered without an
estimation of the wheel-space temperature. For example, a
determination can be made as to the source of a deviation between
the expected value and the measured value and whether it is due to
for example, but not limited to, a lack of cooling, a leakage, or
worn seals. Moreover, rapidly changing operational conditions or
very slowly changing operational conditions may make it difficult
for an operator to recognize anomalous conditions or what
operational changes can be made to mitigate the anomalous
conditions.
[0003] At least some known wheel-space monitoring systems monitor
the measured values only and using historical data for the same
type of machine static thresholds are predefined, so that if the
measured value exceeds the predefined threshold, an alarm is
raised. Many attempts are needed to define and refine these
thresholds, which do not take into account the machine running or
load conditions. Such systems are prone to too many false alarms,
and actual faults are generally detected too late. Moreover, only
limited or no troubleshooting information is provided in such
systems.
SUMMARY OF THE INVENTION
[0004] In one embodiment, a computer-implemented method for
monitoring and diagnosing anomalies in a wheel-space of a gas
turbine implemented using a computer device coupled to a user
interface and a memory device includes storing a plurality rule
sets in the memory device, the rule sets relative to the
wheel-space, the rule sets including at least one rule expressed as
a relational expression of a real-time data output relative to a
real-time data input, the relational expression being specific to a
temperature of the wheel-space. The method also includes receiving
real-time and historical data inputs from a condition monitoring
system associated with the gas turbine, the data inputs relating to
sources providing heat to the wheel-space and estimating a
wheel-space temperature value using the inputs relating to a
temperature of the wheel-space.
[0005] In another embodiment, a wheel-space monitoring and
diagnostic system for a gas turbine including an axial compressor
and a low pressure turbine in flow communication includes a
wheel-space temperature rule set, the rule set including a
relational expression of a real-time data output relative to a
real-time data input, the relational expression being specific to
inputs relating to sources of heat in the wheel-space.
[0006] In yet another embodiment, one or more non-transitory
computer-readable storage media has computer-executable
instructions embodied thereon, wherein when executed by at least
one processor, the computer-executable instructions cause the
processor to receive a measured value of a temperature in a
wheel-space of a gas turbine, receive measured values and inferred
values of parameters associated with sources of heat into the
wheel-space, estimate an expected temperature of the wheel-space,
compare the expected temperature to the measured temperature of the
wheel-space, and generate an advisory message recommending an
action to be taken based on the comparison.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIGS. 1-5 show exemplary embodiments of the method and
system described herein.
[0008] FIG. 1 is a schematic block diagram of a remote monitoring
and diagnostic system in accordance with an exemplary embodiment of
the present invention;
[0009] FIG. 2 is a block diagram of an exemplary embodiment of a
network architecture of a local industrial plant monitoring and
diagnostic system, such as a distributed control system (DCS);
[0010] FIG. 3 is a block diagram of an exemplary rule set that may
be used with LMDS shown in FIG. 1;
[0011] FIG. 4 is a side elevation view of an architecture of a
wheel-space cooling system of a gas turbine engine partially shown
in FIG. 1 in accordance with an exemplary embodiment of the present
disclosure; and
[0012] FIG. 5 is a flow diagram of a method of determining advice
for an engine wheel-space temperature that exceeds a predetermined
range in accordance with an exemplary embodiment of the present
disclosure.
[0013] Although specific features of various embodiments may be
shown in some drawings and not in others, this is for convenience
only. Any feature of any drawing may be referenced and/or claimed
in combination with any feature of any other drawing.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The following detailed description illustrates embodiments
of the invention by way of example and not by way of limitation. It
is contemplated that the invention has general application to
analytical and methodical embodiments of monitoring equipment
operation in industrial, commercial, and residential
applications.
[0015] Health monitoring of gas turbines is important to reduce
maintenance costs and outage periods. The wheel-space temperature
in the low pressure turbine (power turbine) of a gas turbine is a
significant signal to monitor. Exposed to the hot gas path, the
wheel-space may be vulnerable to fatigue/creep failure from thermal
stresses. Estimating the wheel-space temperature requires knowing
the sources of temperatures contribute to the wheel-space
temperature and indicate how to monitor it and better estimate it.
Knowing the sources of heat in the wheel-spaces permits a greater
understanding of the status of the cooling system of the machine to
highlight improper thermal behavior and excessive temperatures in
the wheel-space area. In addition, by comparing this estimated
wheel-space temperature to the actual measured wheel-space
temperature, alarms based on this difference and define
troubleshooting activities can be devised. The wheel-space
temperature calculation method described below links the different
components of a gas turbine together and simplifies identifying the
source of the fault, for example, an excessive wheel-space
temperature. Described herein is a method for online estimation of
wheel-space temperature and generation of an engineering rule to
prevent trips and/or prolonged shutdown periods and to provide
meaningful troubleshooting.
[0016] Possible sources of heat contributing to the wheel-space
temperature in a gas turbine engine include: hot gas form the
combustion process that can be ingested, axial compressor bleed
(cooling) air, and rotor windage effects. The bleed temperature is
used initially as a baseline for the wheel-space temperature and
compensate for the other effects to estimate it. The bleed
temperature is calculated online using a thermodynamic simulation
software that is used to monitor the performance of the machine.
This is done by calculating the polytropic efficiency of the axial
compressor and, then, extracting the bleed temperature (air
temperature where the bleed is extracted). The difference between
the wheel-space temperature and the bleed (cooling) temperature is
not constant and depends on the flow path temperature. In some gas
turbine engines, the turbine exhaust temperature is the only flow
path temperature directly measured and is used herein to estimate
the wheel-space temperature. There is a linear relationship between
the wheel-space temperature rise above the bleed temperature on one
hand and the exhaust temperature rise above the bleed temperature
on the other. When the rule is initially deployed, the slope of
this curve is calculated and averaged over a suitable period of
time. This is then used to calculate the wheel-space temperature
using the measured exhaust temperature and the calculated bleed
temperature as described below in greater detail.
[0017] Embodiments of the present disclosure are not limited to
detecting a high wheel-space temperature but is able to identify
trends of a difference of wheel-space temperature and a real-time
determined value of expected wheel-space temperature. A statistical
tuning approach is added to the thermodynamic equation that enables
the tuning directly on a running machine for all environments from
an ambient inlet condition and correlating with machine running
conditions.
[0018] FIG. 1 is a schematic block diagram of remote monitoring and
diagnostic system 100 in accordance with an exemplary embodiment of
the present invention. In the exemplary embodiment, system 100
includes a remote monitoring and diagnostic center 102. Remote
monitoring and diagnostic center 102 is operated by an entity, such
as, an OEM of a plurality of equipment purchased and operated by a
separate business entity, such as, an operating entity. In the
exemplary embodiment, the OEM and operating entity enter into a
support arrangement whereby the OEM provides services related to
the purchased equipment to the operating entity. The operating
entity may own and operate purchased equipment at a single site or
multiple sites. Moreover, the OEM may enter into support
arrangements with a plurality of operating entities, each operating
their own single site or multiple sites. The multiple sites each
may contain identical individual equipment or pluralities of
identical sets of equipment, such as trains of equipment.
Additionally, at least some of the equipment may be unique to a
site or unique to all sites.
[0019] In the exemplary embodiment, a first site 104 includes one
or more process analyzers 106, equipment monitoring systems 108,
equipment local control centers 110, and/or monitoring and alarm
panels 112 each configured to interface with respective equipment
sensors and control equipment to effect control and operation of
the respective equipment. The one or more process analyzers 106,
equipment monitoring systems 108, equipment local control centers
110, and/or monitoring and alarm panels 112 are communicatively
coupled to an intelligent monitoring and diagnostic system 114
through a network 116. Intelligent monitoring and diagnostic (IMAD)
system 114 is further configured to communicate with other on-site
systems (not shown in FIG. 1) and offsite systems, such as, but not
limited to, remote monitoring and diagnostic center 102. In various
embodiments, IMAD 114 is configured to communicate with remote
monitoring and diagnostic center 102 using for example, a dedicated
network 118, a wireless link 120, and the Internet 122.
[0020] Each of a plurality of other sites, for example, a second
site 124 and an nth site 126 may be substantially similar to first
site 104 although may or may not be exactly similar to first site
104.
[0021] FIG. 2 is a block diagram of an exemplary embodiment of a
network architecture 200 of a local industrial plant monitoring and
diagnostic system, such as a distributed control system (DCS) 201.
The industrial plant may include a plurality of plant equipment,
such as gas turbines, centrifugal compressors, gearboxes,
generators, pumps, motors, fans, and process monitoring sensors
that are coupled in flow communication through interconnecting
piping, and coupled in signal communication with DCS 201 through
one or more remote input/output (I/O) modules and interconnecting
cabling and/or wireless communication. In the exemplary embodiment,
the industrial plant includes DCS 201 including a network backbone
203. Network backbone 203 may be a hardwired data communication
path fabricated from twisted pair cable, shielded coaxial cable or
fiber optic cable, for example, or may be at least partially
wireless. DCS 201 may also include a processor 205 that is
communicatively coupled to the plant equipment, located at the
industrial plant site or at remote locations, through network
backbone 203. It is to be understood that any number of machines
may be operatively connected to network backbone 203. A portion of
the machines may be hardwired to network backbone 203, and another
portion of the machines may be wirelessly coupled to backbone 203
via a wireless base station 207 that is communicatively coupled to
DCS 201. Wireless base station 207 may be used to expand the
effective communication range of DCS 201, such as with equipment or
sensors located remotely from the industrial plant but, still
interconnected to one or more systems within the industrial
plant.
[0022] DCS 201 may be configured to receive and display operational
parameters associated with a plurality of equipment, and to
generate automatic control signals and receive manual control
inputs for controlling the operation of the equipment of industrial
plant. In the exemplary embodiment, DCS 201 may include a software
code segment configured to control processor 205 to analyze data
received at DCS 201 that allows for on-line monitoring and
diagnosis of the industrial plant machines. Data may be collected
from each machine, including gas turbines, centrifugal compressors,
pumps and motors, associated process sensors, and local
environmental sensors including, for example, vibration, seismic,
temperature, pressure, current, voltage, ambient temperature and
ambient humidity sensors. The data may be pre-processed by a local
diagnostic module or a remote input/output module, or may
transmitted to DCS 201 in raw form.
[0023] A local monitoring and diagnostic system (LMDS) 213 may be a
separate add-on hardware device, such as, for example, a personal
computer (PC), that communicates with DCS 201 and other control
systems 209 and data sources through network backbone 203. LMDS 213
may also be embodied in a software program segment executing on DCS
201 and/or one or more of the other control systems 209.
Accordingly, LMDS 213 may operate in a distributed manner, such
that a portion of the software program segment executes on several
processors concurrently. As such, LMDS 213 may be fully integrated
into the operation of DCS 201 and other control systems 209. LMDS
213 analyzes data received by DCS 201, data sources, and other
control systems 209 to determine an operational health of the
machines and/or a process employing the machines using a global
view of the industrial plant.
[0024] In the exemplary embodiment, network architecture 100
includes a server grade computer 202 and one or more client systems
203. Server grade computer 202 further includes a database server
206, an application server 208, a web server 210, a fax server 212,
a directory server 214, and a mail server 216. Each of servers 206,
208, 210, 212, 214, and 216 may be embodied in software executing
on server grade computer 202, or any combinations of servers 206,
208, 210, 212, 214, and 216 may be embodied alone or in combination
on separate server grade computers coupled in a local area network
(LAN) (not shown). A data storage unit 220 is coupled to server
grade computer 202. In addition, a workstation 222, such as a
system administrator's workstation, a user workstation, and/or a
supervisor's workstation are coupled to network backbone 203.
Alternatively, workstations 222 are coupled to network backbone 203
using an Internet link 226 or are connected through a wireless
connection, such as, through wireless base station 207.
[0025] Each workstation 222 may be a personal computer having a web
browser. Although the functions performed at the workstations
typically are illustrated as being performed at respective
workstations 222, such functions can be performed at one of many
personal computers coupled to network backbone 203. Workstations
222 are described as being associated with separate exemplary
functions only to facilitate an understanding of the different
types of functions that can be performed by individuals having
access to network backbone 203.
[0026] Server grade computer 202 is configured to be
communicatively coupled to various individuals, including employees
228 and to third parties, e.g., service providers 230. The
communication in the exemplary embodiment is illustrated as being
performed using the Internet, however, any other wide area network
(WAN) type communication can be utilized in other embodiments,
i.e., the systems and processes are not limited to being practiced
using the Internet.
[0027] In the exemplary embodiment, any authorized individual
having a workstation 232 can access LMDS 213. At least one of the
client systems may include a manager workstation 234 located at a
remote location. Workstations 222 may be embodied on personal
computers having a web browser. Also, workstations 222 are
configured to communicate with server grade computer 202.
Furthermore, fax server 212 communicates with remotely located
client systems, including a client system 236 using a telephone
link (not shown). Fax server 212 is configured to communicate with
other client systems 228, 230, and 234, as well.
[0028] Computerized modeling and analysis tools of LMDS 213, as
described below in more detail, may be stored in server 202 and can
be accessed by a requester at any one of client systems 204. In one
embodiment, client systems 204 are computers including a web
browser, such that server grade computer 202 is accessible to
client systems 204 using the Internet. Client systems 204 are
interconnected to the Internet through many interfaces including a
network, such as a local area network (LAN) or a wide area network
(WAN), dial-in-connections, cable modems and special high-speed
ISDN lines. Client systems 204 could be any device capable of
interconnecting to the Internet including a web-based phone,
personal digital assistant (PDA), or other web-based connectable
equipment. Database server 206 is connected to a database 240
containing information about industrial plant 10, as described
below in greater detail. In one embodiment, centralized database
240 is stored on server grade computer 202 and can be accessed by
potential users at one of client systems 204 by logging onto server
grade computer 202 through one of client systems 204. In an
alternative embodiment, database 240 is stored remotely from server
grade computer 202 and may be non-centralized.
[0029] Other industrial plant systems may provide data that is
accessible to server grade computer 202 and/or client systems 204
through independent connections to network backbone 204. An
interactive electronic tech manual server 242 services requests for
machine data relating to a configuration of each machine. Such data
may include operational capabilities, such as pump curves, motor
horsepower rating, insulation class, and frame size, design
parameters, such as dimensions, number of rotor bars or impeller
blades, and machinery maintenance history, such as field
alterations to the machine, as-found and as-left alignment
measurements, and repairs implemented on the machine that do not
return the machine to its original design condition.
[0030] A portable vibration monitor 244 may be intermittently
coupled to LAN directly or through a computer input port such as
ports included in workstations 222 or client systems 204.
Typically, vibration data is collected in a route, collecting data
from a predetermined list of machines on a periodic basis, for
example, monthly or other periodicity. Vibration data may also be
collected in conjunction with troubleshooting, maintenance, and
commissioning activities. Further, vibration data may be collected
continuously in a real-time or near real-time basis. Such data may
provide a new baseline for algorithms of LMDS 213. Process data may
similarly, be collected on a route basis or during troubleshooting,
maintenance, and commissioning activities. Moreover, some process
data may be collected continuously in a real-time or near real-time
basis. Certain process parameters may not be permanently
instrumented and a portable process data collector 245 may be used
to collect process parameter data that can be downloaded to DCS 201
through workstation 222 so that it is accessible to LMDS 213. Other
process parameter data, such as process fluid composition analyzers
and pollution emission analyzers may be provided to DCS 201 through
a plurality of on-line monitors 246.
[0031] Electrical power supplied to various machines or generated
by generated by generators with the industrial plant may be
monitored by a motor protection relay 248 associated with each
machine. Typically, such relays 248 are located remotely from the
monitored equipment in a motor control center (MCC) or in
switchgear 250 supplying the machine. In addition, to protection
relays 248, switchgear 250 may also include a supervisory control
and data acquisition system (SCADA) that provides LMDS 213 with
power supply or power delivery system (not shown) equipment located
at the industrial plant, for example, in a switchyard, or remote
transmission line breakers and line parameters.
[0032] FIG. 3 is a block diagram of an exemplary rule set 280 that
may be used with LMDS 213 (shown in FIG. 1). Rule set 280 may be a
combination of one or more custom rules, and a series of properties
that define the behavior and state of the custom rules. The rules
and properties may be bundled and stored in a format of an XML
string, which may be encrypted based on a 25 character alphanumeric
key when stored to a file. Rule set 280 is a modular knowledge cell
that includes one or more inputs 282 and one or more outputs 284.
Inputs 282 may be software ports that direct data from specific
locations in LMDS 213 to rule set 280. For example, an input from a
pump outboard vibration sensor may be transmitted to a hardware
input termination in DCS 201. DCS 201 may sample the signal at that
termination to receive the signal thereon. The signal may then be
processed and stored at a location in a memory accessible and/or
integral to DCS 201. A first input 286 of rule set 280 may be
mapped to the location in memory such that the contents of the
location in memory is available to rule set 280 as an input.
Similarly, an output 288 may be mapped to another location in the
memory accessible to DCS 201 or to another memory such that the
location in memory contains the output 288 of rule set 280.
[0033] In the exemplary embodiment, rule set 280 includes one or
more rules relating to monitoring and diagnosis of specific
problems associated with equipment operating in an industrial
plant, such as, for example, a gas reinjection plant, a liquified
natural gas (LNG) plant, a power plant, a refinery, and a chemical
processing facility. Although rule set 280 is described in terms of
being used with an industrial plant, rule set 280 may be
appropriately constructed to capture any knowledge and be used for
determining solutions in any field. For example, rule set 280 may
contain knowledge pertaining to economic behavior, financial
activity, weather phenomenon, and design processes. Rule set 280
may then be used to determine solutions to problems in these
fields. Rule set 280 includes knowledge from one or many sources,
such that the knowledge is transmitted to any system where rule set
280 is applied. Knowledge is captured in the form of rules that
relate outputs 284 to inputs 282 such that a specification of
inputs 282 and outputs 284 allows rule set 280 to be applied to
LMDS 213. Rule set 280 may include only rules specific to a
specific plant asset and may be directed to only one possible
problem associated with that specific plant asset. For example,
rule set 280 may include only rules that are applicable to a motor
or a motor/pump combination. Rule set 280 may only include rules
that determine a health of the motor/pump combination using
vibration data. Rule set 280 may also include rules that determine
the health of the motor/pump combination using a suite of
diagnostic tools that include, in addition to vibration analysis
techniques, but may also include, for example, performance
calculational tools and/or financial calculational tools for the
motor/pump combination.
[0034] In operation, rule set 280 is created in a software
developmental tool that prompts a user for relationships between
inputs 282 and outputs 284. Inputs 282 may receive data
representing, for example digital signals, analog signals,
waveforms, processed signals, manually entered and/or configuration
parameters, and outputs from other rule sets. Rules within rule set
280 may include logical rules, numerical algorithms, application of
waveform and signal processing techniques, expert system and
artificial intelligence algorithms, statistical tools, and any
other expression that may relate outputs 284 to inputs 282. Outputs
284 may be mapped to respective locations in the memory that are
reserved and configured to receive each output 284. LMDS 213 and
DCS 201 may then use the locations in memory to accomplish any
monitoring and/or control functions LMDS 213 and DCS 201 may be
programmed to perform. The rules of rule set 280 operate
independently of LMDS 213 and DCS 201, although inputs 282 may be
supplied to rule set 280 and outputs 284 may be supplied to rule
set 280, directly or indirectly through intervening devices.
[0035] During creation of rule set 280, a human expert in the field
divulges knowledge of the field particular to a specific asset
using a development tool by programming one or more rules. The
rules are created by generating expressions of relationship between
outputs 284 and inputs 282 such that no coding of the rules is
needed. Operands may be selected from a library of operands, using
graphical methods, for example, using drag and drop on a graphical
user interface built into the development tool. A graphical
representation of an operand may be selected from a library portion
of a screen display (not shown) and dragged and dropped into a rule
creation portion. Relationships between input 282 and operands are
arranged in a logical display fashion and the user is prompted for
values, such as, constants, when appropriate based on specific
operands and specific ones of inputs 282 that are selected. As many
rules that are needed to capture the knowledge of the expert are
created. Accordingly, rule set 280 may include a robust set of
diagnostic and/or monitoring rules or a relatively less robust set
of diagnostic and/or monitoring rules based on a customer's
requirements and a state of the art in the particular field of rule
set 280. The development tool provides resources for testing rule
set 280 during the development to ensure various combinations and
values of inputs 282 produce expected outputs at outputs 284.
[0036] In one embodiment, a wheel-space temperature rule set is
configured to calculate an expected wheel-space temperature with
respect to operating conditions of the gas turbine engine. The
benefit of the wheel-space temperature rule set is a predictive and
adaptable threshold that links different GT components and
Compressor Performance to predict the upper and lower bounds on the
expected wheel-space temperature.
[0037] FIG. 4 is a side elevation view of an architecture of a
wheel-space cooling system 400 of a gas turbine engine 401
(partially shown in FIG. 1) in accordance with an exemplary
embodiment of the present disclosure. A compressor 402 provides
high pressure air to components of gas turbine engine 401. In the
exemplary embodiment, a first wheel-space forward zone 403 is
cooled only by air routed from a compressor discharge section 404.
A first wheel-space aft zone 406 is cooled with air routed from
compressor discharge section 404 and air bled from a compressor
stage 408 upstream from compressor discharge section 404, for
example, but not limited to the eleventh stage of compressor 402.
Second wheel-space forward 410 and second wheel-space aft 412 are
cooled by air bled from upstream compressor stage 408.
[0038] The wheel-spaces temperatures in the low pressure turbine of
gas turbine engine 401 are monitored by, for example, a first
thermocouple 414 and a second thermocouple 416 positioned within
first wheel-space forward zone 403 and a third thermocouple 418 and
a second thermocouple 420 positioned within second wheel-space aft
412. Two thermocouples for each space furnish the information on
air temperature inside the cavities.
[0039] A temperature (CDT) of air routed from a compressor
discharge section 404 is monitored with sensors and can be directly
compared with wheel-space temperature, a temperature of upstream
compressor stage 408, which cannot be measured directly is
evaluated in a correlation that accounts for operating conditions
of compressor.
[0040] Rules defined for gas turbine engine 401 are based on
providing an expected value for the wheel-space temperature and
comparing such a value with measured values. Advice provided by the
rules for an anomaly are output when the measured value differs
from the expected value by more than a predetermined amount that is
not dependent on gas turbine engine 401. The predetermined amount
is instead related to package settings, cold clearances, running
clearances, and packs mounted on gas turbine engine 401, which all
may affect a base value that is defined in the very first period of
rules application to gas turbine engine 401.
[0041] Compressor Bleed Temperature Calculation
[0042] To link the wheel-space temperature to the evaluated
upstream compressor stage 408 the following correlations are used.
Such a correlation refers to the polytropic efficiency of the
compressor which is assumed to be constant through the different
stages and allows the evaluation of the air temperature along the
compression process at each time step.
[0043] Input for such a correlation are: [0044] T2 Compressor inlet
temperature (monitored), [0045] T3 Compressor outlet temperature
(monitored), [0046] P2 Compressor inlet pressure (monitored) [0047]
P3 Compressor outlet pressure (monitored)
[0048] The correlation outputs the bleed pressure and temperature
to be compared with the second wheel-space temperature.
[0049] Extraction pressure is evaluated as a function of compressor
discharge pressure (P3) as:
P 11 = ? , ? indicates text missing or illegible when filed ( 1 )
##EQU00001##
where f.sub.P11(T) is a third order polynomial function of
compressor inlet temperature whose coefficients are summarized in
Table 1.
[0050] The actual polytropic efficiency .eta..sub.act can be
evaluated as:
.eta. act = ? ? indicates text missing or illegible when filed ( 2
) ##EQU00002##
where .gamma.(T) and f(T) are expressed by third order polynomial
functions defined by coefficients in table 1.
TABLE-US-00001 TABLE 1 Coefficients for Polynomial Expressions
Function C0 C1 C2 C3 fP 11 (T) 2.22457469922934E+00
-4.63874892302590E-03 2.44926189613996E-05 -1.27947433407930E-07
.gamma.(T) 1.40029450459100E+00 -1.87667861261292E-06
-9.09273412720000E-08 4.44183762000000E-11 f(T)
-6.71976186797772E+01 3.75674097649753E+00 -4.16444150209530E-02
2.11683533804297E-04
[0051] Finally the upstream stage (stage 11, for example,) air
temperature can be calculated as:
T 11 = T 2 ( P 11 P 2 ) ? ? indicates text missing or illegible
when filed ( 3 ) ##EQU00003##
where T.sub.3* is evaluated as:
T 3 * = 2 T 3 + f ( T 2 ) 2 ( 4 ) ##EQU00004##
[0052] Analysis of data for different machines indicates that a
simple .DELTA.T based correlation is not sufficiently accurate. The
data indicate a large variability between the wheel-space
temperature and the upstream stage (stage 11, for example,) air
temperature bleed temperature.
[0053] The flow path temperature is taken into account. The only
flow path temperature measurement in, for example, gas turbine
engine 401 is a turbine exit temperature (T5). The temperatures of
second wheel-space forward 410 and second wheel-space aft 412 were
observed to be closely dependent on turbine exit temperature
(T5).
[0054] Because such an effect in the correlation is useful a
constant .theta. is introduced, which can be expressed as:
.theta. = ( TTWS 2 - T 11 ) ( T 5 - T 11 ) = const . ( 5 )
##EQU00005##
[0055] A value for .theta. is defined for each gas turbine engine
and has characteristic values for the type of machine. Once the
.theta. value is set for the forward and after side of the second
wheel-space, the predicted wheel-space temperature is evaluated
as:
TTWS2.sub.fwd=T11+.theta..sub.fwd(T5-T11) (6)
for the forward side and as:
TTWS2.sub.aft=T.sub.11+.theta..sub.aft(T5-T11) (7)
for the aft side.
[0056] The rules for wheel-space temperature based on signals
acquired or inferred by the system are described below, as well as
the expected values and the thresholds.
[0057] A first wheel-space forward temperature is strongly related
to the Compressor Discharge Temperature (T3). A simple but still
reliable correlation is to set a constant temperature difference
between the two. Such a difference is a characteristic of the
machine even if its value can be assumed be in the range
0-60.degree. Celsius. The standard machine has a typical base line
temperature difference of approximately 40-60.degree. Celsius while
other machines may have a lower temperature difference of
approximately 10-15.degree. Celsius. Once a base line temperature
difference is fixed, the wheel-space temperature is expected not to
vary more than approximately .+-.15.degree. Celsius.
[0058] First wheel-space aft cooling is provided from a combination
of compressor discharge air and the upstream compressor stage air,
for example, the 11.sup.th stage air. Comparing both temperatures
to the measured wheel-space temperature indicates a relatively
large dependency on the turbine exit temperature.
[0059] In one embodiment, because both the compressor discharge air
and the upstream compressor stage air flows affect the wheel-space
temperature an average of the two is used for comparison:
T mix = T 11 + T 3 2 , ( 8 ) ##EQU00006##
where T11 is evaluated following the steps described above and T3
is the measured value of compressor discharge temperature. There is
a linear dependency of (TTWS1AFT-Tmix) on (T5-Tmix). In various
embodiments, other combinations of compressor discharge air and the
upstream compressor stage air flows are used for the comparison.
For example, each may be weighted with respect to one other or
other flows may also be combined with the compressor discharge air
and the upstream compressor stage air flows.
[0060] The following step is therefore to evaluate the .theta.
ratio that can be assumed constant and used to evaluate the
wheel-space temperature as:
TTWS1.sub.aft=T.sub.mix+.theta.(T5-T.sub.mix) (9)
[0061] In other embodiments, a mass-flow average value for
T.sub.mix may be used.
[0062] The source for cooling the forward and after second
wheel-spaces is for example, the compressor 11.sup.th stage bleed
air. The temperature for the cooling air flow is evaluated from the
measured values of pressure and temperature at the inlet and outlet
section of the compressor according to the procedure described
above.
[0063] The wheel-space temperature can be evaluated by introducing
a constant, .theta. which allows for an accurate prediction of the
wheel-space temperature.
[0064] In one case, .theta. constants, were determined to be
.theta..sub.fwd=0.289 and .theta..sub.aft=0.345. Using such
constants it is possible to predict the wheel-space temperature
with an error included of approximately .+-.10.degree. Celcius.
[0065] Rules for the second wheel-spaces temperature and first
wheel-space aft were determined to account for turbine exit
temperature and allowing for an error in a prediction lower than
approximately .+-.15.degree. Celsius in all cases. First
wheel-space forward temperature is correlated with compressor
discharge temperature without a need for other parameters to be
evaluated. All rules described in above take into account expected
values and machine dependent settings. Each rule definition is
preceded by a period of calibration during which the characteristic
parameters are set according to the monitored results.
[0066] FIG. 5 is a flow diagram of a method 500 of determining
advice for an engine wheel-space temperature that exceeds a
predetermined range in accordance with an exemplary embodiment of
the present disclosure. In the exemplary embodiment, method 500
includes storing 502 a plurality rule sets in the memory device,
the rule sets relative to the wheel-space, the rule sets including
at least one rule expressed as a relational expression of a
real-time data output relative to a real-time data input, the
relational expression being specific to a temperature of the
wheel-space, receiving 504 real-time and historical data inputs
from a condition monitoring system associated with the gas turbine,
the data inputs relating to sources providing heat to the
wheel-space, and estimating 506 a wheel-space temperature value
using the inputs relating to a temperature of the wheel-space.
[0067] The logic flows depicted in the figures do not require the
particular order shown, or sequential order, to achieve desirable
results. In addition, other steps may be provided, or steps may be
eliminated, from the described flows, and other components may be
added to, or removed from, the described systems. Accordingly,
other embodiments are within the scope of the following claims.
[0068] It will be appreciated that the above embodiments that have
been described in particular detail are merely example or possible
embodiments, and that there are many other combinations, additions,
or alternatives that may be included.
[0069] Also, the particular naming of the components,
capitalization of terms, the attributes, data structures, or any
other programming or structural aspect is not mandatory or
significant, and the mechanisms that implement the invention or its
features may have different names, formats, or protocols. Further,
the system may be implemented via a combination of hardware and
software, as described, or entirely in hardware elements. Also, the
particular division of functionality between the various system
components described herein is merely one example, and not
mandatory; functions performed by a single system component may
instead be performed by multiple components, and functions
performed by multiple components may instead performed by a single
component.
[0070] Some portions of above description present features in terms
of algorithms and symbolic representations of operations on
information. These algorithmic descriptions and representations may
be used by those skilled in the data processing arts to most
effectively convey the substance of their work to others skilled in
the art. These operations, while described functionally or
logically, are understood to be implemented by computer programs.
Furthermore, it has also proven convenient at times, to refer to
these arrangements of operations as modules or by functional names,
without loss of generality.
[0071] Unless specifically stated otherwise as apparent from the
above discussion, it is appreciated that throughout the
description, discussions utilizing terms such as "processing" or
"computing" or "calculating" or "determining" or "displaying" or
"providing" or the like, refer to the action and processes of a
computer system, or similar electronic computing device, that
manipulates and transforms data represented as physical
(electronic) quantities within the computer system memories or
registers or other such information storage, transmission or
display devices.
[0072] While the disclosure has been described in terms of various
specific embodiments, it will be recognized that the disclosure can
be practiced with modification within the spirit and scope of the
claims.
[0073] The term processor, as used herein, refers to central
processing units, microprocessors, microcontrollers, reduced
instruction set circuits (RISC), application specific integrated
circuits (ASIC), logic circuits, and any other circuit or processor
capable of executing the functions described herein.
[0074] As used herein, the terms "software" and "firmware" are
interchangeable, and include any computer program stored in memory
for execution by processor 205, including RAM memory, ROM memory,
EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory.
The above memory types are exemplary only, and are thus not
limiting as to the types of memory usable for storage of a computer
program.
[0075] As will be appreciated based on the foregoing specification,
the above-described embodiments of the disclosure may be
implemented using computer programming or engineering techniques
including computer software, firmware, hardware or any combination
or subset thereof, wherein the technical effect includes (a)
storing a plurality rule sets in the memory device wherein the rule
sets pertain to the wheel-space and include at least one rule
expressed as a relational expression of a real-time data output
relative to a real-time data input wherein the relational
expression is specific to a temperature of the wheel-space, (b)
receiving real-time and historical data inputs from a condition
monitoring system associated with the gas turbine, the data inputs
relating to sources providing heat to the wheel-space, (c)
estimating a wheel-space temperature value using the inputs
relating to a temperature of the wheel-space, (d) comparing the
estimated wheel-space temperature to an actual measured wheel-space
temperature, (e) generating an advisory message using the
comparison, the advisory message including troubleshooting
activities relating to the wheel-space temperature, (f) receiving
inputs representative of heat contained in at least one of hot gas
from a combustion process of the gas turbine, bleed cooling air
from an axial compressor of the gas turbine, and rotor windage
effects, (g) setting an initial estimated baseline for the
wheel-space temperature is equal to a temperature of the axial
compressor bleed cooling air and compensated using other sources of
heat to the wheel-space, (h) setting an initial estimated baseline
for the wheel-space temperature is equal to a temperature of the
axial compressor bleed cooling air compensated using at least one
of a temperature of hot gas from the combustion process and rotor
windage effects, (i) determining the estimated wheel-space
temperature online using a thermodynamic simulation of the
performance of the gas turbine, (j) determining the estimated
wheel-space temperature online using a polytropic efficiency of the
axial compressor and the axial compressor bleed cooling air
temperature, (k) determining the slope of the linear relationship
between the wheel-space temperature and the axial compressor bleed
cooling air temperature, (l) determining the slope of the linear
relationship between the temperature of the turbine exhaust and the
axial compressor bleed cooling air temperature, and (m) iteratively
averaging the slope over a selectable period of time. Any such
resulting program, having computer-readable code means, may be
embodied or provided within one or more computer-readable media,
thereby making a computer program product, i.e., an article of
manufacture, according to the discussed embodiments of the
disclosure. The computer readable media may be, for example, but is
not limited to, a fixed (hard) drive, diskette, optical disk,
magnetic tape, semiconductor memory such as read-only memory (ROM),
and/or any transmitting/receiving medium such as the Internet or
other communication network or link. The article of manufacture
containing the computer code may be made and/or used by executing
the code directly from one medium, by copying the code from one
medium to another medium, or by transmitting the code over a
network.
[0076] Many of the functional units described in this specification
have been labeled as modules, in order to more particularly
emphasize their implementation independence. For example, a module
may be implemented as a hardware circuit comprising custom very
large scale integration ("VLSI") circuits or gate arrays,
off-the-shelf semiconductors such as logic chips, transistors, or
other discrete components. A module may also be implemented in
programmable hardware devices such as field programmable gate
arrays (FPGAs), programmable array logic, programmable logic
devices (PLDs) or the like.
[0077] Modules may also be implemented in software for execution by
various types of processors. An identified module of executable
code may, for instance, comprise one or more physical or logical
blocks of computer instructions, which may, for instance, be
organized as an object, procedure, or function. Nevertheless, the
executables of an identified module need not be physically located
together, but may comprise disparate instructions stored in
different locations which, when joined logically together, comprise
the module and achieve the stated purpose for the module.
[0078] A module of executable code may be a single instruction, or
many instructions, and may even be distributed over several
different code segments, among different programs, and across
several memory devices. Similarly, operational data may be
identified and illustrated herein within modules, and may be
embodied in any suitable form and organized within any suitable
type of data structure. The operational data may be collected as a
single data set, or may be distributed over different locations
including over different storage devices, and may exist, at least
partially, merely as electronic signals on a system or network.
[0079] The above-described embodiments of a method and online
wheel-space temperature monitoring system that includes a rule
module provides a cost-effective and reliable means for providing
meaningful operational recommendations and troubleshooting actions.
Moreover, the system is more accurate and less prone to false
alarms. More specifically, the methods and systems described herein
can predict component failure at a much earlier stage than known
systems to facilitate significantly reducing outage time and
preventing trips. In addition, the above-described methods and
systems facilitate predicting anomalies at an early stage enabling
site personnel to prepare and plan for a shutdown of the equipment.
As a result, the methods and systems described herein facilitate
operating gas turbines and other equipment in a cost-effective and
reliable manner.
[0080] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the disclosure is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *