Apparatus and methods for field testing an electrical panel meter system

Patent metadata

Field	Value
Publication number	US-2016259026-A1
Application number	US-201514840376-A
Country	US
Kind code	A1
Filing date	Aug 31, 2015
Priority date	Mar 4, 2015
Publication date	Sep 8, 2016
Grant date	—

Abstract

An electrical panel meter system may include a plurality of meter modules housed in an electrical panel enclosure. Each meter module may be configured to sample electrical readings related to electrical power provided to a respective branch circuit of the electrical panel meter system. To field test the metering accuracy of each meter module, a field tester may be coupled to the electrical panel enclosure. The field tester may inject an electrical signal via a test conductor provided in the electrical panel enclosure. The test conductor may be coupled to each meter module. The field tester may measure an electrical parameter of the injected electrical signal and compare it to electrical readings sampled by the meter modules. A pass/fail result for each meter module may be indicated. Methods of field testing meter modules in an electrical panel meter system are also provided, as are other aspects.

First claim

What is claimed is:

1 . A field tester for testing metering accuracy, the field tester comprising:
a reference power meter; a current source having an output coupled to an input of the reference power meter; a computer coupled to the reference power meter and to the current source, the computer comprising a processor and a memory; a plurality of power conductors coupled to the reference power meter and to the current source and configured to be coupled to a respective plurality of terminals of a main line connector of an electrical panel meter system; a first conductor coupled to an output of the reference power meter and configured to be coupled to a first terminal of a test conductor of the electrical panel meter system, the test conductor coupled sequentially to each meter module of the electrical panel system; a second conductor coupled to a return of the current source and configured to be coupled to a second terminal of the test conductor; and a third conductor coupled to the computer and configured to be coupled to a controller of the electrical panel meter system.

2 . The field tester of claim 1 , wherein the plurality of power conductors comprises an A phase conductor, a B phase conductor, a C phase conductor, and a neutral conductor.

3 . The field tester of claim 1 , wherein the reference power meter has an accuracy rating of 0.02% or better.

4 . The field tester of claim 1 , wherein the current source is configured to receive line-to-line voltage of up to about 480 volts AC and generate up to about 20 amps AC current for 20 to 60 seconds.

5 . The field tester of claim 1 , wherein the computer is a laptop computer.

6 . The field tester of claim 1 , wherein the computer is configured to:
issue a test mode command to the controller; command the current source to output an electrical signal via the first conductor; and command the reference power meter to measure a parameter related to the electrical signal.

7 . The field tester of claim 6 , wherein the parameter comprises an energy value.

8 . The field tester of claim 1 , wherein the computer is configured to:
issue a send command to the controller to have at least some of the plurality of meter modules sample electrical readings of an electrical signal passing through the test conductor and send the sampled electrical readings back to the computer; receive the sampled electrical readings; compare the received electrical readings to a parameter of the electrical signal measured by the reference power meter; and indicate a pass/fail result for each of the at least some of the plurality of meter modules.

9 . An electrical panel meter system configured to be field tested for metering accuracy, the electrical panel meter system comprising:
a plurality of branch circuit connectors, each one of the plurality of branch circuit connectors configured to be coupled to a respective branch circuit to provide electrical power thereto; a plurality of current sensors, each one of the plurality of current sensors coupled to a respective one of the plurality of branch circuit connectors; a plurality of meter modules, each one of the plurality of meter modules coupled to a respective one of the plurality of current sensors; a controller coupled to the plurality of meter modules; a test conductor coupled sequentially to each one of the plurality of current sensors, the test conductor having no electrical connection to the plurality of branch circuit connectors; a first terminal coupled to one end of the test conductor; and a second terminal coupled to a second opposite end of the test conductor.

10 . The electrical panel meter system of claim 9 , wherein the plurality of current sensors comprise solid core or split core current transformers.

11 . The electrical panel meter system of claim 9 , wherein each one of the plurality of meter modules comprises a meter module processor and a meter module memory and is configured to:
sample an electrical reading in response to receiving a read command from the controller; and transfer a sampled electrical reading to the controller.

12 . The electrical panel meter system of claim 9 , wherein the controller is configured to:
receive a test mode command from a field tester; issue a read command to at least some of the plurality of meter modules in response to receiving a send command from the field tester; receive electrical readings from the at least some of the plurality of meter modules in response to issuing the read command; and send the received electrical readings to the field tester.

13 . A method of field testing an electrical panel meter system for metering accuracy, the method comprising:
coupling a plurality of conductors from a field tester to the electrical panel meter system; injecting an electrical signal from the field tester into the electrical panel meter system; measuring at the field tester a parameter of the electrical signal; receiving an electrical reading from each of at least some of a plurality of meter modules of the electrical panel meter system; comparing each received electrical reading to the measured parameter; and indicating a pass/fail result for each of the at least some of the plurality of meter modules.

14 . The method of claim 13 wherein the measured parameter comprises an energy value.

15 . The method of claim 13 wherein the coupling of the plurality of conductors comprises coupling first and second conductors from the field tester to first and second terminals, respectively, of a test conductor coupled sequentially to a plurality of current sensors of the electrical panel meter system, each one of the plurality of current sensors coupled to a respective one of the plurality of meter modules.

16 . The method of claim 15 wherein the injecting of the electrical signal from the field tester into the electrical panel meter system comprises injecting the electrical signal into the first terminal via the first conductor.

17 . The method of claim 13 wherein the coupling of the plurality of conductors comprises:
coupling a plurality of power conductors from the field tester to a respective plurality of terminals of a main line connector of the electrical panel meter system; and
coupling a third conductor from the field tester to a controller of the electrical panel meter system.

18 . The method of claim 13 wherein the injecting of the electrical signal from the field tester into the electrical panel meter system comprises synchronizing the electrical signal to a first power phase-to-neutral voltage.

19 . The method of claim 13 wherein the receiving of the electrical reading from each of the at least some of the plurality of meter modules of the electrical panel meter system comprises receiving the electrical reading from each of the plurality of meter modules coupled to a first power phase.

20 . The method of claim 13 further comprising:
issuing a test mode command from the field tester to the electrical panel meter system after the coupling of the plurality of conductors and before the injecting of the electrical signal; and
issuing a send command from the field tester to the electrical panel meter system before the receiving the electrical reading from each of the least some of the plurality of meter modules.

Assignees

• Siemens Industry Inc

Inventors

• Leidy Matthew
• Miller Kevin

Classifications

• G01R35/04 Primary

  of instruments for measuring time integral of power or current · CPC title

• G01R35/00 Primary

  Testing or calibrating of apparatus covered by the other groups of this subclass · CPC title

• G01R22/061

  Details of electronic electricity meters · CPC title