Power line communications module and method
A device and method for communicating user data and utility metrology data over a power line is provided. In one embodiment, the method includes measuring a utility parameter to provide the utility data; storing the utility data in memory; transmitting the utility data over the power line; receiving first data via the power line from a first device; and transmitting the first data over the power line to a second device. In addition, the method may include receiving the first data and transmitting the first data with different encryption keys and also determining if the first data includes control data.
FIELD OF THE INVENTION
The present invention generally relates to data communications over a power distribution system and more particularly, to a communications module for communicating utility meter data and power line communications data.
BACKGROUND OF THE INVENTION
Well-established power distribution systems exist throughout most of the United States, and other countries, which provide power to customers via power lines. With some modification, the infrastructure of the existing power distribution systems can be used to provide data communication in addition to power delivery, thereby forming a power line communication system (PLCS). In other words, existing power lines that already have been run to many homes and offices, can be used to carry data signals to and from the homes and offices. These data signals are communicated on and off the power lines at various points in the power line communication system, such as, for example, near homes, offices, Internet service providers, and the like.
There are many challenges to overcome in order to use power lines for data communication. Power lines are not designed to provide high speed data communications and can be very susceptible to interference. Additionally, federal regulations limit the amount of radiated energy of a power line communication system, which therefore limits the strength of the data signal that can be injected onto power lines (especially overhead power lines). Consequently, due to the attenuation of power lines, communications signals typically will travel only a relatively short distance on power lines. In addition, the distance may vary from location to location.
Power line communication systems often communicate with user devices in the customer premises, which typically are coupled directly or indirectly to an internal low voltage (LV) power line network. This communication typically involves transmitting signals along the external LV power lines, through an electric meter, and along the internal LV power lines to the user device. However, the electric meter, which measures the power consumed by the customer premises and is connected to the LV power lines, sometimes attenuates the data signals. Additionally, in some instances the length of the LV power lines and associated attenuation can hamper or prevent reliable communications. Additionally, ingress noise and noise from home appliances can degrade communications performance.
Automated meter reading (AMR) has been investigated as a means for reducing the cost of reading meters. The high capital cost of replacing meters and building an AMR system in a large geographical area has hindered wide scale adoption of automated meter reading.
Thus, there is a need for a communications module and method that facilitates automated electric meter reading and reliable communication of user data signals that can be dynamically configured and reconfigured by a network management system. These and other advantages may be provided by various embodiments of the present invention.
SUMMARY OF THE INVENTION
The present invention includes a device and method for communicating user data and utility metrology data over a power line. In one embodiment, the method includes measuring a utility parameter to provide the utility data; storing the utility data in memory; transmitting the utility data over the power line; receiving first data via the power line from a first device; and transmitting the first data over the power line to a second device. In addition, the method may include receiving the first data and transmitting the first data with different encryption keys and also determining if the first data includes control data.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is further described in the detailed description that follows, by reference to the noted drawings by way of non-limiting illustrative embodiments of the invention, in which like reference numerals represent similar parts throughout the drawings. As should be understood, however, the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular networks, communication systems, computers, terminals, devices, components, techniques, PLCS, data and network protocols, software products and systems, operating systems, development interfaces, hardware, etc. in order to provide a thorough understanding of the present invention.
However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. Detailed descriptions of well-known networks, communication systems, computers, PLCS, terminals, devices, components, techniques, data and network protocols, software products and systems, operating systems, development interfaces, and hardware are omitted so as not to obscure the description of the present invention.
As shown in
In addition to HV transmission lines, power distribution systems include MV power lines and LV power lines. MV typically ranges from about 1000 V to about 100 kV and LV typically ranges from about 100 V to about 800 V. Transformers are used to convert between the respective voltage portions, e.g., between the HV section and the MV section and between the MV section and the LV section. Transformers have a primary side for connection to a first voltage (e.g., the MV section) and a secondary side for outputting another (usually lower) voltage (e.g., the LV section). Transformers used between the MV section and the LV section are often referred to as distribution transformers or as step down transformers, because they “step down” the voltage to some lower voltage. Transformers, therefore, provide voltage conversion for the power distribution system. Thus, power is carried from substation transformer to a distribution transformer over one or more MV power lines. Power is carried from the distribution transformer to the customer premises via one or more LV power lines.
In addition, a distribution transformer may function to distribute one, two, or three, phase voltages to the customer premises, depending upon the demands of the user. In the United States, for example, these local distribution transformers typically feed anywhere from one to ten homes, depending upon the concentration of the customer premises in a particular area. Distribution transformers may be pole-top transformers located on a utility pole, pad-mounted Underground Residential Distribution (URD) transformers located on the ground, or transformers located under ground level.
One example of a portion of a conventional PLCS is shown in
In this example embodiment, the BD 100 provides communication services for the user, which may include security management, routing of Internet Protocol (IP) packets, filtering data, access control, service level monitoring, signal processing and modulation/demodulation of signals transmitted over the power lines.
This example portion of a PLCS also includes a backhaul point 10. The backhaul point 10 is an interface and gateway between a portion of a PLCS (e.g., an MV run) and a traditional non-power line telecommunications network. One or more backhaul points (BP) 10 may be communicatively coupled to an aggregation point (AP) 20 that in many embodiments may be at (e.g., co-located with), or connected to, the point of presence to the Internet. The BP 10 may be connected to the AP 20 using any available mechanism, including fiber optic conductors, T-carrier, Synchronous Optical Network (SONET), or wireless techniques well known to those skilled in the art. Thus, the BP 10 may include a transceiver suited for communicating through the communication medium that comprises the backhaul link.
The PLCS also may include a power line server (PLS) that is a computer system with memory for storing a database of information about the PLCS and includes a network element manager (NEM) that monitors and controls the PLCS. The PLS allows network operations personnel to provision users and network equipment, manage customer data, and monitor system status, performance and usage. The PLS may reside at a remote network operations center (NOC), and/or at a PLCS Point of Presence (POP), to oversee a group of communication devices via the Internet. The PLS may provide an Internet identity to the network devices by assigning the devices (e.g., user devices, BDs 100, (e.g., the LV modems and MV modems of BDs), BPs 10, and AP 20) IP addresses and storing the IP addresses and other device identifying information (e.g., the device's location, address, serial number, etc.) in its memory. In addition, the PLS may approve or deny user devices authorization requests, command status reports, statistics and measurements from the BDs, and BPs, and provide application software upgrades to the communication devices (e.g., BDs, BPs, and other devices). The PLS, by collecting electric power ,distribution information and interfacing with utilities' back-end computer systems may provide enhanced power distribution services such as automated meter reading, outage detection, restoration detection, load balancing, distribution automation, Volt/Volt-Amp Reactance (Volt/VAr) management, and other similar functions. The PLS also may be connected to one or more APs and/or core routers directly or through the Internet and therefore can communicate with any of the BDs, user devices, and BPs through the respective AP and/or core router.
The PLCS may further include indoor low voltage repeaters and outdoor low voltage repeaters. Indoor low voltage repeaters may be plugged into a wall socket inside the customer premises. Outdoor low voltage repeaters may be coupled to the external low voltage power line conductors extending from the transformer and therefore, be located between the customer premises and the BD 100. Both the indoor low voltage repeaters and outdoor low voltage repeaters repeat data on the low voltage power line to extend the communication range of the BD 100 and power line modem.
At the user end of the PLCS of this example system, data flow originates from a user device, which provides the data to a power line modem (PLM) 50, which is well-known in the art.
The user device connected to the PLM 50 may be any device capable of supplying data for transmission (or for receiving such data) including, but not limited to a computer, a telephone, a telephone answering machine, a fax, a digital cable box (e.g., for processing digital audio and video, which may then be supplied to a conventional television and for transmitting requests for video programming), a video game, a stereo, a videophone, a television (which may be a digital television), a video recording device (which may be a digital video recorder), a home network device, a direct load control switch, utility distribution automation equipment, or other device. The PLM 50 transmits the data received from the user device through the LV power lines to a BD 100 and provides data received from the LV power line to the user device. The PLM 50 may also be integrated with the user device, which may be a computer. In addition and as discussed herein, the functions of the PLM may be integrated into a smart utility meter such as a gas meter, electric meter, water meter, or other utility meter to thereby provide automated meter reading (AMR).
The BD 100 typically receives data from the user devices coupled to its LV power line subnet and then transmits the data to (and receives the data from) the backhaul point 10, which, in turn, transmits the data to (and receives the data from) the AP 20. The AP 20 then transmits the data to (and receives the data from) the appropriate destination (perhaps via a core router), which may be a network destination (such as an Internet address) in which case the packets are transmitted to, and pass through, numerous routers (herein routers are meant to include both network routers and switches) in order to arrive at the desired destination. A detailed description of an example PLCS, its components and features is provided in U.S. patent application Ser. No. 11/091,677 filed Mar. 28, 2005, Attorney Docket No. CRNT-0239, entitled “Power Line Repeater System and Method,” which is hereby incorporated by reference in its entirety. A detailed description of another example PLCS, its components and features is provided in U.S. patent application Ser. No. 10/973,493 filed Oct. 26, 2004, Attorney Docket No. CRNT-0229, entitled “Power Line Communications System and Method of Operating the Same,” which is hereby incorporated by reference in its entirety. The present invention may be used with networks as described in the above patent applications or others. Thus, the invention is not limited to a particular PLCS, PLCS architecture, or topology.
Similarly, BD 100b is coupled to backhaul point 10 via the MV power line and also coupled to LV power line subnet 61b to provide communications to the user devices coupled thereto. In this example, LV power line subnet 61b includes the LV power lines coupled to distribution transformer 60b. One or more of the customer premises receiving power via LV power line subnet 61b may include one or more PLMs 50 and the associated user devices connected thereto such as, for example, at CP 119c, 119d, and 119e. Thus, as shown in
This example embodiment includes a power line interface 2020 which is coupled to modem 2022. Power line interface 2020 may include impedance matching circuitry, a band filter, an amplifier, power signal isolation circuitry, transmit and receive circuitry, and other conditioning circuitry. As shown, power line interface 2020 may be coupled to both energized conductors L1 and L2 and may transmit data by differentially coupling the data signals onto the power line conductors (e.g., via a transformer therein) and similarly receiving the data. In addition, the power line interface 2020 may provide frequency translation. While this embodiment communicates over two energized power line conductors, other embodiments may communicate over one energized conductor or three energized conductors (three phase service).
The modem 2022 may be a HomePlug compliant or compatible power line modem (e.g., substantially comply or compatible with HomePlug 1.0, Turbo, or AV) and employ OFDM for communications over the power line. The modem 2022 is communicatively coupled to the processor 2040. The processor 2040 may be in communication with memory 2045, which may include volatile and non-volatile random access memory (RAM) which may be used to store utility metrology data, including power usage data, collected from the meter 300 and program code to be executed by the processor 2040. Other utility metrology data (or referred to herein as utility data) may include, but is not limited to Voltage (peak/average/threshold) data, Current (peak/average/threshold) data, power factor data, phase angle data, peak power data, average power data, voltage sag data, voltage swell data, neutral current, peak reverse power data, and average reverse power data. As will be evident to one skilled in the art, some of these data types may comprise raw measurements and others may be derived from raw measurement data. Additionally, one or more of these may cause the processor 2040 to generate (and transmit) an alert such as an Alert on detection of reverse power, voltage sag, voltage swell, voltage out of limit (too high or low), etc.
New program code may also be received via the energized conductors (e.g., the external power line conductors) from a network element, such as a bypass device, of the PLCS. The new code may then be stored in flash memory for execution by the processor 2040. The module 2000 may be configured by to enable or disable repeating of power line communications via a command from a network element, such as a bypass device, of the PLCS. The enabling or repeating of PLC data may thus be achieved by the processor 2040 executing program code and in response to receiving a command.
The processor 2040 may also be in communication with the meter via a power meter interface 2042 in order to receive data and perform other AMR processes. A power supply 2055 is coupled to the processor 2040, modem 2022, and other components to provide power thereto.
The utility data (e.g., power usage data) may be received by the module 2000 and transmitted via the LV power line to a power line communications system network element, which may be, for example, a transformer bypass device 100. The network element may then transmit the utility data (e.g., via the MV power line) to an upstream device (e.g., a backhaul device 10), which further transmits the utility data upstream for eventual reception by utility provider. Additionally, the module 2000 may receive user data from the bypass device 100 and transmit the data over the LV power line for reception by one or more user devices in the customer premises. Similarly, the module 2000 may receive user data from one or more user devices in the customer premises and transmit the user data over the LV power line to the bypass device 100 or other network element. Examples of such a power line communications systems and network elements are described in the applications incorporated above.
In operation, data signals will be received from the internal LV power line via line interface 2020. After conditioning by line interface 2020, the signals will be provided to modem 2022. However, if a data packet received by modem 2022 does not have a destination address (e.g., media access control address or IP address) that corresponds to modem 2022, the data packet may be ignored. In other instances, the data signals received by the modem 2022 may have been encrypted by the transmitting device. If the modem has the correct encryption key, the modem may successfully decrypt the data packets. However, if the modem 2022 does not have the correct encryption key, the modem 2022 will not be able to successfully decrypt the data packet and the data will be ignored. A first key may be used for communications between the module 2000 and user devices and a second key may be used for communications between the module 2000 and its network element (e.g., bypass device). The processor 2040 may control which keys modem 2022 uses. If the packet is not correctly addressed or encrypted, the data may be discarded and not repeated by module 2000. Other means of selectively repeating the data may also be employed.
There are various reasons for employing selective repeating and/or multiple encryption keys. As discussed above, if communications between the bypass device and the user device are not reliable, the user device may sometimes receive data from the bypass device. If the module 2000 is repeating all data packets, it is possible that the user device (or the bypass device) may receive the same packet twice (transmitted once from the module and once from the bypass device), which would likely cause an error. To prevent this occurrence, the bypass device and the user devices (i.e., their power line modems) may use different encryption keys for communications on the LV power line. This creates a logical isolation of the internal and external networks. Additionally, the bypass device may communicate with a plurality of user devices in different customer premises, which are electrically connected by the LV power lines. Using a different encryption key for each customer premises ensures that user devices in one customer premises cannot receive data transmitted by or to user devices in another customer premises. Additionally, it may be desirable to repeat user data to increase the signal strength of the user data, which may allow for increased data speed.
In an alternate example embodiment, LV power line communications with the bypass device and the user devices (i.e., their power line modems) may use different frequency bands. In this embodiment, the power line interface 2020 may include frequency translation circuitry for translation from the 4-21 MHz band to the 20-50 MHz band. Thus, in this embodiment, Homeplug compliant data signals (e.g., Homeplug 1.0, HomePlug Turbo, or Homeplug AV) between the module 2000 and user devices may use the 20-50 MHz band and communications between the module 2000 and the bypass device may use the 4-21 MHz (or vice versa). Thus, because they communicate in different frequency bands, the user devices and the bypass device cannot “accidentally” communicate with each other. In this embodiment, the power line interface may have two different input and output filters (one for each band) and two frequency translation circuits—one for upbanding the output of the modem to the higher frequency band and one for downbanding the input of the higher frequency to the modem's native frequency band. This embodiment may be implemented by having the processor 2040 control the frequency band at which the power line interface 2020 communicates. Alternately, if a modem that supported two frequency bands were used, processor 2040 may control the frequency used by modem 2022. The modem 2022 could also communicate via its native frequency or frequencies.
In the first embodiment, if repeating is enabled, and the data packet is successfully decrypted, the demodulated data packet is supplied to the processor 2040. Processor 2040 may process the data packet(s) and if the packet contains a command may perform one or more activities. Such commands and associated activities may include transmit utility data, update schedule of transmissions of utility data, disable repeating, enable repeating, receive and store new program code, store new IP address, and others. Processor 2040 may determine a data packet includes a command by any suitable method such as identify packets having a destination IP address corresponding to that of module 2000, which is stored in memory 2045. If the packet is not a command, the processor 2040 may supply the same received data packet back to the modem for transmission onto the LV conductors. In addition to supplying the data packet to the modem 2022, the processor 2040 also may supply information of the encryption key to be used to encrypt the data packet (or, in an alternate embodiment, information to control the frequency band of transmission). If repeating is disabled, the processor 2040 does not supply the packet back to the modem 2022 or alternately may disable the modem 2022. In an alternate embodiment, the data received by the processor 2040 from modem 2022 also may be re-addressed by processor 2040 with the destination address (e.g., MAC address) of the user device that corresponds to the destination address of the data packet. Thus, the processor 2040 may include router (or switch) functionality.
Instead of a single modem (modem 2022 of
In a second embodiment, instead of using different encryption keys the two power line interface circuits 2010 and 2020 may be configured to receive and transmit in different frequency bands to perform the logical isolation of networks described above. In this embodiment, the power line interface 2020 may not include frequency translation and be configured to receive and transmit in the 4-21 MHz band. Power line interface 2010 may include two frequency translation circuits—one for upbanding the output of the modem to the higher frequency band (e.g., 30-50 MHz) and one for downbanding the input of the higher frequency to 4-21 MHz used by the modem. Alternatively, the modem itself may communicate on 4-21 or 30-50 as selected by Processor 2040. In still another embodiment, a natively upbanded modem chip may be used. Thus, one frequency may be used to communicate with user devices and the other for communicating with the bypass device.
In operation, the module 2000 works substantially the same as the embodiment of
In the embodiments disclosed, utility data such as power usage data, gas usage data, water usage data and electric voltage data, may be stored in memory of the module and transmitted to the network element 1) periodically, 2) upon receiving a request to transmit the data from the network element, 3) when memory in the device reaches a threshold percentage of capacity, 4) upon a triggering event such as an out of limit voltage measurement; and/or 4) at the occurrence of other events. The device may also store data from multiple meters (e.g., a gas, water, and power meter) and may be connected to such other non-power meters via a coaxial cable, a twisted pair, Ethernet cable, wirelessly, or other suitable medium. In some instances, localized noise may increase the noise floor at a device and degrade that device's ability to receive data. Thus, it may be desirable to only repeat data communications in one direction. Consequently, in some of the embodiments disclosed herein and others, it may not be necessary to repeat data in both directions. In other words, the device (or module 2000) may be configured to repeat only upstream data (data transmitted from the user device) or only downstream data (data transmitted to the user device). The module 2000 may be configure itself via channel testing and/or by receiving an appropriate command.
In still another embodiment, the implementation of
Finally, the type of data signals communicated via the MV and LV power lines can be any suitable type of data signal. The type of signal modulation used can be any suitable signal modulation used in communications (Code Division Multiple Access. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiplex (FDM), Orthogonal Frequency Division Multiplex (OFDM), and the like). OFDM may be used for one or both of the LV and MV power lines, including HomePlug 1.0, HomePlug Turbo or HomePlug AV data signals. A modulation scheme producing a wideband signal such as CDMA or OFDM that is relatively flat in the spectral domain may be used to reduce radiated interference to other systems while still delivering high data communication rates. Thus, the example communication module described above may be used with frequency division multiplexed communication systems or time division multiplexed communication systems.
In addition, instead of using OFDM signals on the MV power line or LV power line, an alternate embodiment of a PLCS system may use ultra wideband signals to provide communications over the MV and/or LV power lines.
It is to be understood that the foregoing illustrative embodiments have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the invention. Words used herein are words of description and illustration, rather than words of limitation. In addition, the advantages and objectives described herein may not be realized by each and every embodiment practicing the present invention. Further, although the invention has been described herein with reference to particular structure, materials and/or embodiments, the invention is not intended to be limited to the particulars disclosed herein. Rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may affect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention.
1. A method of communicating data over a power line, comprising:
- measuring a utility parameter to provide utility data;
- storing the utility data in memory;
- transmitting the utility data over the power line;
- receiving first data via the power line from a first device; and
- transmitting the first data over the power line to a second device.
2. The method of claim 1, further comprising:
- receiving second data via the power line; and
- not transmitting the second data over the power line.
3. The method of claim 1, wherein the first device comprises a medium voltage (MV) access device.
4. The method of claim 1, wherein the first device comprises a user device.
5. The method of claim 1, further comprising
- decrypting the received first data with a first key; and
- encrypting the first data with a second key prior to said transmitting of the first data.
6. The method of claim 1, wherein the first data is received in a first frequency band and transmitted in a second frequency band different from the first frequency band.
7. The method of claim 1, further comprising:
- determining whether the first data is to be repeated; and
- transmitting the first data over the power line only if the first user data is to be repeated.
8. The method of claim 7, further comprising determining whether the first data includes a command if the first data is not to be repeated.
9. The method of claim 1, wherein said receiving first data and said transmitting first data are performed with different encryption keys.
10. The method of claim 1, wherein further comprising determining if the first data includes control data.
11. The method of claim 1, wherein said receiving and said transmitting of the first data are performed by the same modem.
12. The method of claim 1, wherein said receiving and said transmitting of the first data are performed by different modems.
13. The method of claim 1, further comprising receiving a command to disable repeating.
14. The method of claim 1, further comprising receiving a command that includes a request to transmit the utility data.
15. The method of claim 1, further comprising:
- receiving second data via the power line from the second device; and
- transmitting the second data over the power line to the first device.
16. A device for communicating user data and utility over a power line; comprising:
- a memory configured to store utility data;
- a processor in communication with said memory;
- a communication module in communication with said processor and configured to be communicatively coupled to the power line;
- wherein said processor is configured to cause said module to transmit utility data over the power line; and
- wherein said processor is configured to cause said module to receive and transmit user data via the power line.
17. The device of claim 16, wherein the power line includes a first and second energized conductor and said module is configured to be communicatively coupled to the first and the second energized conductor to differentially transmit data signals over the energized conductors.
18. The device of claim 16, wherein the power line comprises an external power line supplying power to a customer premises and the user data includes data received from a user device in the customer premises.
19. The device of claim 16, wherein the user data includes data received from a MV power line access device.
20. The device of claim 19, wherein the MV power line access device comprises a transformer bypass device.
21. The device of claim 16, wherein said module is configured to receive and decrypt user data with a first encryption key and to encrypt and transmit user data with a second encryption key.
22. The device of claim 21, wherein said module is further configured to receive and decrypt user data with the second first encryption key and to encrypt and transmit user data with the first encryption key.
23. The device of claim 16, wherein said communication module includes a first and second modem configured to be coupled to the power line.
24. The device of claim 23, further comprising a data signal impedance configured to be coupled to the power line to between said first and second modems.
25. The device of claim 23, wherein said first and second modem are configured to communicate using different encryption keys.
26. The device of claim 16, wherein said communication module includes only a single modem.
27. A method of communicating utility data and non-utility data over a power line, comprising:
- storing the utility data in memory;
- transmitting the utility data over the power line;
- receiving first data via the power line;
- determining whether the first data is to be repeated; and
- transmitting the first data over the power line if the first data is to be repeated.
28. The method of claim 27, further comprising determining whether the first data includes a command.
29. The method of claim 27, wherein said receiving the first data and said transmitting the first data are performed with different encryption keys.
30. The method of claim 27, wherein said determining includes determining if the first data includes control data.
31. The method of claim 27, wherein said receiving the first data and said transmitting the first data are performed in different frequency bands.
32. The method of claim 27, wherein said receiving the first data and said transmitting the first data are performed by the same modem.
33. The method of claim 27, further comprising receiving a command to disable repeating.
34. The method of claim 27, further comprising receiving a command that includes a request to transmit the utility data.
35. The method of claim 27, further comprising receiving a command to enable repeating.
36. The method of claim 27, wherein said transmitting the utility data is performed periodically.
37. The method of claim 27, wherein said transmitting the utility data is performed intermittently.
38. The method of claim 27, further comprising:
- receiving program code via the power line; and
- storing the program code in memory.
39. The method of claim 27, further comprising
- receiving second data via the power line; and
- transmitting the second data over the power line.
40. The method of claim 39, wherein
- said receiving the first data and said transmitting the second data are performed with a first encryption key; and
- said receiving the second data and said transmitting the first data are performed with a second encryption key.
41. The method of claim 27, further comprising transmitting an alert over the power line based on the value of the utility data.
International Classification: G08C 15/06 (20060101);