U.S. patent application number 11/183900 was filed with the patent office on 2005-11-10 for method and apparatus for attaching power line communications to customer premises.
This patent application is currently assigned to Telkonet Communications, Inc.. Invention is credited to Crenshaw, Ralph E., Grimes, David W., Larson, L. Peter.
Application Number | 20050248441 11/183900 |
Document ID | / |
Family ID | 31886601 |
Filed Date | 2005-11-10 |
United States Patent
Application |
20050248441 |
Kind Code |
A1 |
Crenshaw, Ralph E. ; et
al. |
November 10, 2005 |
Method and apparatus for attaching power line communications to
customer premises
Abstract
A method and apparatus for modifying a three-phase power
distribution network in a building in order to provide data
communication by using a Power Line Carrier (PLC) signal to an
approximate electrical central location point of the power
distribution system remote from the data entry point of the
building. A passive coupler device is attached to a centrally
located service panel. The passive coupler receives the Power Line
Carrier (PLC) signal from the remote entry point in the building
and conditions the signal for entry at the service panel onto each
phase of the three phase power distribution network.
Inventors: |
Crenshaw, Ralph E.;
(Crowsville, MD) ; Grimes, David W.; (Trappe,
MD) ; Larson, L. Peter; (Annapolis, MD) |
Correspondence
Address: |
CROWELL & MORING LLP
INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
Telkonet Communications,
Inc.
|
Family ID: |
31886601 |
Appl. No.: |
11/183900 |
Filed: |
July 19, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11183900 |
Jul 19, 2005 |
|
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|
10219811 |
Aug 16, 2002 |
|
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60326205 |
Oct 2, 2001 |
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Current U.S.
Class: |
370/401 ; 307/2;
709/249; 709/250 |
Current CPC
Class: |
H04B 3/56 20130101; H04B
3/542 20130101; H04B 2203/5433 20130101; H04B 2203/5483 20130101;
H04B 2203/5445 20130101; H04B 2203/5466 20130101 |
Class at
Publication: |
340/310.18 ;
709/249; 709/250; 307/002 |
International
Class: |
H04M 011/04 |
Claims
1-38. (canceled)
39. A system for interfacing a communication device with a
multiple-phase power network residing in a building, wherein the
multiple-phase power network includes multiple power wires with
each power wire corresponding to a respective phase of the
multiple-phase power network, and wherein the multiple-phase power
network also includes a first service panel located within the
building, the system comprising: an electronic network coupled to
the communication device via a first interface, wherein the first
interface does not include any power wire of the multiple-phase
power network residing in the building; wherein the electronic
network includes one or more carrier current couplers each
providing an electrical interface between the communication device
and a respective power wire of the three-phase power network at the
first service panel, and wherein the electronic network is
configured to split a first communication signal received from the
communication device and feed the split communication signal to
each power wire of the multiple-phase power network at the first
service panel through the one or more carrier current couplers such
that the first communication signal can be effectively distributed
throughout at least a portion of the building.
40. The system according to claim 39, wherein the first interface
is composed primarily of a coaxial cable.
41. The system according to claim 40, wherein the electronic
network includes a coaxial splitter, and wherein each of the
carrier current couplers is electrically coupled to the
splitter.
42. The system according to claim 39, wherein the communication
device is a gateway.
43. The system according to claim 42, wherein the communication
device is a gateway forming a hub-and-spoke network LAN
topology.
44. The system according to claim 42, wherein the communication
device is configured to provide a broadband signal, and the
electronic network is configured to split the broadband signal and
feed it to each power wire of the multiple-phase power network
45. The system according to claim 39, wherein the power network is
a three-phase power network, and the electronic network is
configured to split the broadband signal into three portions and
feed it to each power wire of the multiple-phase power network.
46. The system according to claim 45, wherein the three-phase power
network is fed from an external power source via a step-down
transformer.
47. The system according to claim 46, wherein the power network
employs voltages below 277 volts.
48. The system according to claim 47, wherein the power network
includes a plurality of service panels, and the first service panel
is electrically the most centrally located of the service
panels.
49. A method for interfacing a communication device with a
three-phase power network residing in a building, wherein the
three-phase power network includes at least three power wires each
corresponding to a respective phase of the three-phase power
network, and wherein the three-phase power network also includes a
first service panel located within the building, the method
comprising: receiving a first communication signal from a
communication device; splitting the communication signal into three
portions; and feeding the portions of the split communication
signal to each power wire of the three-phase power network at the
first service panel such that the first communication signal can be
effectively distributed throughout at least a portion of the
building receiving at least one of the power wires.
50. The method according to claim 49, wherein the communication
device is a gateway.
51. The method according to claim 49, wherein the communication
device is a hub forming a hub-and-spoke network LAN topology.
52. The method according to claim 41, wherein the communication
device is configured to provide a broadband signal, and the
electronic network is configured to split the broadband signal and
feed it to each power wire of the three-phase power network.
53. The method according to claim 49, wherein the power network
includes a plurality of service panels, and the first service panel
is electrically the most centrally located of the service
panels.
54. A system for interfacing a communication device with a
three-phase power network residing in a building, wherein the
three-phase power network includes at least three power wires each
corresponding to a respective phase of the three-phase power
network, the system comprising: an interface means for providing an
electrical interface between the communication device and the
three-phase power network; wherein the interface means splits a
first communication signal received from the communication device
into three portions and simultaneously feeds the split
communication signal to each power wire of the three-phase power
network at a common location such that the first communication
signal can be effectively distributed throughout at least a portion
of the building receiving at least one of the power wires.
55. The system according to claim 54, wherein the three-phase power
network also includes a first service panel located within the
building, and wherein the electronic network is located inside the
building in physical proximity to the first service panel.
56. The system according to claim 54, wherein the communication
device is a gateway forming a hub-and-spoke network LAN
topology.
57. The system according to claim 56, wherein the communication
device is configured to provide a broadband signal, and the
electronic network is configured to split the broadband signal and
feed it to each power wire of the three-phase power network
58. The system according to claim 56, wherein the power network
includes a plurality of service panels, and the first service panel
is electrically the most centrally located of the service
panels.
59. The system according to claim 46, wherein the power network
employs voltages below 277 volts.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] This application claims the priority of Provisional
Application Ser. No. 60/326,205, filed October 2, 2001, the
disclosure of which is expressly incorporated by reference
herein.
[0002] The ability to interconnect computers and other intelligent
devices is a common requirement wherever people live and work
today. The electrical connection required to form this local area
network (LAN) has traditionally been accomplished by installing
dedicated data wiring both inside buildings and between clusters of
buildings. A number of wireless (i.e. radio) methods have also been
developed and deployed to address this need.
[0003] More recently, technology to allow electric power wiring
infrastructure to simultaneously transport data at high rates has
been realized. This Power Line Carrier (PLC) technology typically
uses modulated radio frequency (RF) signals below 50 MHz conducted
on the power wiring to transport the data.
[0004] There are significant practical advantages offered by PLC
technology--namely that electrical wiring, of necessity, must be
installed and that data connectivity can therefore be immediately
added at little (or no) additional cost, particularly in existing
buildings. Similarly, electrical outlets are ubiquitous within
modem buildings and significant operating convenience is realized
when data is simultaneously available at every outlet.
[0005] Another advantage of PLC technology is that the range that
can be achieved is significantly greater than wireless methods,
particularly in commercial buildings constructed of heavier
materials that severely attenuate wireless signals. Yet another
advantage of PLC technology over wireless methods is that the data
is inherently more secure since a physical connection is required
to join the network.
[0006] The invention described here addresses several important
problems that arise in the installation and use of PLC technology
for local area data networks.
[0007] Most contemporary LANs are configured in a "hub and spoke"
topology where a central server device supports a number of users
and also provides a gateway to the Wide Area Network (WAN) and/or
the Internet. Maximum utility for a PLC network is obtained when
its' physical configuration mirrors the logical topology of the
LAN, i.e. when the PLC gateway is effectively located at the
"electrical center" of the space such that every outlet is served
with the best possible PLC signal. This point is often a rarely
accessed electrical panel in a service closet or the basement and
is almost never co-located with other data processing equipment.
The invention provides a simple means to remotely inject the PLC
signals at this optimal point.
[0008] Another important issue, particularly in commercial
buildings, is that 3-phase electrical power/wiring is commonly used
and adequate coverage of a PLC network within the building is
achieved only when all three phases are excited with the PLC
signal. The invention provides for the simultaneous excitation of
all 3 phases of power wiring with a single PLC signal.
[0009] Yet another related issue arises during the installation of
PLC networks in environments that have natural barriers to the
signals (or block them entirely). A common situation is where a
building has been modified and all sections no longer share a
common source of electrical power. Another common situation is
where power is supplied from a central point and then distributed
to sections of the space via transformers, often for purposes of
distribution efficiency or electrical isolation. The invention also
provides a simple and flexible means to inject a single PLC signal
into any number of remote points as required to obtain adequate
coverage.
[0010] The system according to the present invention interfaces a
communicating signal with a three-phase power network of a building
by feeding a power line carrier signal to a remotely located
coupling device which is constructed to enable each of the three
phases to be supplied with the PLC signal from the remote signal
source. In another respect of the present invention, the signal can
be fed to two or more different parts of a building having
different electrical isolation qualities with respect to PLC signal
by providing separate coupling device for each part of the
building.
[0011] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a simplified block diagram illustrating how
electrical power is supplied to and distributed within
buildings.
[0013] FIG. 2 expands a portion of FIG. 1 and illustrates how and
where the coupler constructed in accordance with the present
invention is positioned connected.
[0014] FIG. 3 is a schematic of the coupler according to the
present invention.
[0015] FIG. 4 details an arrangement for improving PLC signal
coverage and is an embodiment of the invention for buildings having
portions which are isolated with respect to communication data.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Embodiments of the current invention are directed to
improving data connectivity afforded by PLC technology. While the
carrier current coupler apparatus described here provides the means
to effect the physical connection to the building power wiring,
much of the improvement derives from identifying the appropriate
point(s) at which to inject the PLC signal.
[0017] One common objective is to inject the PLC signal from a
single, centralized device (often called a "gateway") into the
building wiring in such a way that all receptacles in the building
receive adequate signal for a second device (often called a
"terminal") plugged in there to function properly. The attenuation
of PLC signals along arbitrary runs of wiring is difficult to
predict and highly variable so it is generally not possible to
supply all receptacles with equal signal levels. A more achievable
objective is to have the building and all of its' receptacles taken
together as a system be well-behaved, i.e. where no single
receptacle is completely cut off from the PLC signal and where the
signal amplitude decreases in a reasonably predictable fashion with
distance from the signal injection point.
[0018] FIG. 1 shows a simplified block diagram of a building power
distribution system and will be used to illustrate the above
discussion. Electricity from the utility mains enters the facility
via step down transformer (31) through terminal box (32) and is
measured for billing purposes by meter (33). It is then conducted
to service panel (30) where it is split and further directed to
many receptacles (35) via panel boards (34). It is certainly
possible to inject the gateway PLC signal at any of the above
numbered points however the optimal point is probably service panel
(30) because it symmetrically feeds all of the receptacles (35).
PLC signal attenuated along the wiring from transformer (31) (if
injected there) to the service panel (30) is entirely wasted since
no terminal devices will ever be connected there. Similarly,
injecting the gateway signal at one of the receptacles (35) could
be workable but is probably not optimal since the receptacles are
probably not symmetrically distributed about any given one.
[0019] An optimized system which maximizes use of the passive
coupler arrangement is to connect the carrier current coupler (20)
to service panel (30), inject the PLC signal from gateway (40) into
the building at that point and measure the data throughput
performance at a number of receptacles by any commonly available
means. FIG. 2 illustrates the details of making that
connection.
[0020] Referring to FIG. 2, service panel (30) is the same as
discussed previously. Accepted electrical safety requirements
prescribed in the National Electrical Code require that a cut-off
switch (22) and fuse/circuit breaker (21) be installed. Even though
only minute PLC signal currents are expected to flow along this
path, the cut-off switch (22) is necessary to protect service
personnel from the power line voltage during
installation/maintenance and the fuse/circuit breaker protects the
building in event of a catastrophic failure of the carrier current
coupler (20). Terminal block (23) provides a convenient attachment
point for the wiring.
[0021] An additional dimension to be considered is the common use
of 3-phase power in commercial buildings. In this case, service
panel (30) contains 3 hot wires (often referred to as "L1", "L2"
and "L3"), a neutral and a ground wire. The object of the original
building wiring plan was to balance the load across all 3 phases so
roughly 1/3 of the receptacles (35) downstream will ultimately be
connected to each of L1, L2 and L3. Therefore, to provide PLC
signals to all receptacles, the signal must be split and fed to all
3 phases simultaneously. FIG. 3 illustrates such connection.
[0022] FIG. 3 shows the internal details of the carrier current
coupler (20). The single-ended PLC signal from the gateway is
conducted via coaxial cable (17) and subsequently coupled to each
power phase via balun transformer (14) and capacitor (12).
Capacitor (13) is optional and may or may not be used. Metal oxide
varistor [MOV] (11) is used to suppress power line transients that
might cause damage to the electronics in the gateway (40).
Additional protection to the gateway electronics is provided by
transient voltage suppressor (16). A second fuse (15) (generally
rated at very low amperage) is used to further protect against
short circuit failure of MOV (11). The circuit including capacitor
(12), fuse (15) and MOV (11) is simply replicated to feed all 3
phases.
[0023] If installation is completed as discussed previously and
acceptable data throughput results are obtained, no further work is
necessary. On the other hand, one may find (referring once again to
FIG. 1) that some receptacles (35) will not have adequate PLC
signal. Assume for the purposes of this example that many of the
receptacles (35) fed by one particular panel board (34) do not
deliver adequate data throughput performance. It may be possible by
observation and/or analytical means to determine why such is the
case and remedy the situation. However, details of existing wiring
behind walls and/or the history of prior modifications made to a
building may not be readily apparent. FIG. 4 ("Multi-point PLC
Signal Injection") illustrates a solution to this problem according
to another embodiment afforded by the present invention.
[0024] FIG. 4 shows a PLC signal simultaneously injected at some
point in addition to service panel (30) to remedy a coverage issue.
Coaxial splitter (50) is a commonly available and inexpensive
device used in cable TV systems to split a broadband signal for use
at two or more locations. These devices may likewise be used to
split a PLC signal. In this example, the PLC signal output of
gateway (40) along coaxial cable (17) is split and directed via
individual coaxial cables (18) and (19) to two carrier current
couplers (20), one installed at service panel (30) as before and
another at the particular panel board (34) having receptacles (35)
with inadequate performance. In so doing, whatever physical issues
prevented the original PLC signal from reaching this particular
panel board are circumvented. Further, since all of the PLC signal
power still remains inside the building, the only loss is the
minimal attenuation which occurs in the coaxial splitter (50)
itself. The effect of this process is therefore to provide adequate
signal coverage where before there was none and to slightly reduce
the signal amplitude in the rest of the space. Any number of
variations of this technique can then be employed to address
specific PLC signal coverage issues as they are subsequently
discovered.
[0025] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *