Meter phase identification

The subject matter described herein relates generally to the measurement and testing of power, and more specifically to the identification or placement of conductors, including phase identification.

As shown in FIG. 1, the distribution network 2 is used by an electric power company to supply power from a power plant 4 to a consumer or an end user such as a customer 6. The actual distribution voltage will vary from utility to utility, but in the non-limiting example described herein, three-phase power from power plant 4 is sent to generator setup transformer 8, which is 765V to 138kV on transmission line 10. Power. High-voltage power from transmission line 10 is transmitted to various substations 12, where other transformers 8 diminish this voltage to a lower three-phase voltage, eventually supplying power to three single-phase supplies. The power is distributed to the electric wire 14. Each of these power supply lines 14 is branched into a plurality of circuits to supply power to a plurality of distribution transformers 8 installed on a utility pole or on the ground, and the distribution transformers are for commercial use and residential use. Power the customer's location 6 for and diminish the voltage to the final voltage of 120V and 240V for measurement.

The so-called "smart meter" 16 monitors the power consumption by consumer 6 in detail and then communicates that information to the utility in a process called "telemetry". For example, General Electric Company offers "kV2c" meters and accessories. Various telemetry networks have been proposed for these and other smart meters 16 for power measurement, including cell / pager networks, licensed and unlicensed wireless networks, and power line communication networks. In the case of the power line telemetry network shown in FIG. 1, it is important to know which phase the smart meter is connected to and to be able to transmit this information via the transformer 8.

Ideally, the power supply circuit 14 is designed so that the load at each single-phase output of the three-phase transformer 8 is the same. However, as new customers are added over time, one of the phases becomes heavier than the other. Therefore, in order to readjust the load balance, some of the branch circuits 14 may be switched from the phase of the heavier load to the phase of the lighter load.

<p><patcit num="1"><text>U.S. Pat. No. 5,510,700</text></patcit><patcit num="2"><text>U.S. Pat. No. 7,372,246B2</text></patcit><patcit num="3"><text>U.S. Patent Application Publication No. 2004/0263147A1</text></patcit><patcit num="4"><text>U.S. Patent Application Publication No. 2007/0296396A1</text></patcit><patcit num="5"><text>U.S. Patent Application Publication No. 2008/0116877A1</text></patcit></p>

<p> As a result, the record of which phase of the individual consumer 6 is in the on state for the smart meter 16 installer is incomplete or inaccurate. Therefore, in order to accurately identify the current phase of a particular power supply branch circuit, utility personnel travel through various distribution facilities through various distribution facilities until they reach a point in distribution network 2 where the phase is clearly known. Must be physically tracked. This is an extremely time-consuming and labor-intensive process that often results in incorrect information. In the event of a storm or emergency, it can also be a safety issue.</p>

<p> The above and other drawbacks associated with such a conventional approach are, in various embodiments of the invention, a substation, a signal generator that supplies different signals to each of a plurality of phases exiting the substation, and power. This is addressed by providing a multi-phase power distribution network that includes a signal discriminator that detects different signals in the consumer.</p><p> Various aspects of this technique will then be described with reference to the drawings below, but the drawings are not necessarily drawn to the correct scale and the same reference numbers are used to indicate the corresponding parts throughout each of several drawings. I am using it.</p>

<figref num="1">It is a schematic diagram of a power distribution network.</figref><figref num="2">It is a partial schematic diagram of a power distribution network.</figref><figref num="3">It is a schematic diagram of a smart meter used together with the distribution network shown in FIG.</figref>

FIG. 2 shows a multiphase power distribution network 2 including a substation 12 and a signal generator 20 that supplies different signals to each of a plurality of phases exiting the substation 12. The signal generator 20 may be used with any distribution network 2 including, but not limited to, the network shown in FIG. Although the signal generator 20 is shown as being installed in the substation 12, the signal generator 20 may be installed anywhere in the network 2 and / or the power plant 4 or the transmission line 10 etc. The signal may be supplied at other points in the network. The signal may be supplied in a phase less than all phases and / or at a different position in any of the phases. A separate signal generator 20 may be provided for each phase.

The signal generator (s) 20 supplies a signal that is distinguishable from the typical 60 Hz or 50 Hz power signal delivered by distribution network 2. For example, the signal from the signal generator (s) may have a digital and / or analog frequency greater than or equal to the power frequency of 50-60 Hz. The signal from the signal generator (s) 20 is less than about 60Hz, less than about 50Hz, less than about 30Hz, less than about 25Hz, and / or about because the low frequency signal is less attenuated and can pass through transformer 8. It may have one or more frequency components below 10 Hz. For example, the signal from the signal generator 20 may include an A / C signal having a frequency or frequency component between 1 Hz and less than 60 Hz. Other information about network 2 and / or consumer 6 may be carried by signals from signal generator 20.

The signal discriminator 22 detects different signals from the signal generator 20 respectively. For example, as shown in FIG. 3, a signal discriminator 22 having various components including, but not limited to, one or more current sensors 24, voltage sensors 26, digital / analog processors 28, microprocessors or microcomputers 30. The smart meter 16 may be configured to have. For example, the digital / analog processor 28 may include a multi-channel analog-digital converter, and the microcomputer 30 may include a 32-bit, 32 MHz processor with 2 Mbit ROM, 64 kBit RAM, and a waveform capturer. .. Further, the signal discriminator 22 may include a filter 32. Although the signal discriminator 22 is implemented herein in digital electronic form, any or all components of the smart meter 16 are implemented in analog and / or digital form software, hardware, and / or firmware. May be done.

The signal discriminator 22 and / or other components of the smart meter 16 may be installed at other points in the distribution network 2 such as any transformer 8. In the illustrated embodiment, the signal discriminator 22 receives an input from the feeder (s) 14 and sends the input through the digital filter 32. However, the filter 32 may be implemented as a notch filter or a low-pass filter. The filter 32 may be implemented in analog format.

Various other components of the smart meter 16 such as power supply 34, flash memory 36 and / or EEPROM 38 support the operation of signal discriminator 22. For example, the power supply 34 may be a 120V to 480V DC power supply of various other components, the flash memory 36 may contain 4Mbits containing event logs, load profiles, and auto-read data, and the EEPROM may contain data and program parameters. May contain 64 bits to store. Other types of digital / analog memory may be used.

The above techniques offer various advantages over traditional approaches. For example, it allows utilities and consumers 6 to accurately identify the current phase to which the smart meter 16 and / or other electrical devices are connected without the need to physically track the cable path through various distribution facilities. can do. This technique also provides an easy and effective way to ensure that different devices are connected in the same phase.

It should be emphasized that the above embodiments, and in particular any "favorable" embodiment, are merely examples of the various implementations disclosed herein in order to better understand the various aspects of the technique. One of ordinary skill in the art would be able to modify many of these embodiments without substantially departing from the scope of protection defined only by the proper interpretation of the following claims.

2 Distribution network 4 power plant 6 Consumers 8 transformer 10 power lines 12 substation 14 Feed line 16 smart meter 20 signal generator 22 Signal discriminator 24 current sensor 26 Voltage sensor 28 Digital / Analog Processor 30 microprocessor 32 filters 34 Power supply 36 flash memory 38 EEPROM