Electrical revenue meter and instrument transformers mobile station

• US 6,696,925 B1
• Filed: 02/15/2002
• Issued: 02/24/2004
• Est. Priority Date: 02/15/2002
• Status: Expired due to Fees

• Current Assignee: Lynn-Edward Professional Services, Inc.
• Original Assignee: Lynn-Edward Professional Services, Inc.
• Inventors: Aiello, Michael E. Jr.
• Primary Examiner(s): Lieu, Julie
• Application Number:
  US10/077,087
• Time in Patent Office: 739 Days
• Field of Search: 340/310.01, 340/310.07, 340/310.08, 340/638, 340/635, 361/601, 361/602, 361/603, 361/625, 307/9.1
• US Class Current: 340/870.02
• CPC Class Codes: G01R 15/183 using transformers with a magnetic core
• CPC Class Codes: G01R 22/00 Arrangements for measuring time integral of electric power or current, e.g. electricity meters
• CPC Class Codes: H01F 27/002 Arrangements provided on the transformer facilitating its transport
• CPC Class Codes: H01F 38/26 Constructions

Abstract

A mobile metering system (MMS) comprises a trailer-mounted fully-enclosed three-phase set of current transformers (CTs) and power transformers (PTs), and a metering interface. The instrument transformers reduce the source voltage to a meterable level. The MMS enclosure enables a single utility work crew to connect source-side power bushings mounted on the roof of the MMS to conductors from a compatible source, such as the secondary side of a substation transformer, without the need for a bucket truck. Load-side power bushings are also mounted on the roof of the MMS for connection to the power distribution network. An electromagnetic locking system prevents access to the interior of the enclosure while the MMS is energized. A rigid ground grid mounted on the roof of the MMS grounds the insulators, a ground loop grounds the CTs and PTs, and both the ground grid and the ground loop are connected to the earth ground.

Claims

1. A portable monitoring apparatus for being transported to a location in a electrical power transmission or distribution network and for use in monitoring signals that are carried over a line in the power distribution network, comprising:

a platform for being transported to the location in the electrical power transmission or distribution network;

an instrument transformer mounted to the platform and having a primary side and a secondary side, with the primary side having a greater number of windings than the secondary side and having an input terminal and an output terminal;

a source side bushing, mounted on and insulated from the platform, for connecting a source side of the line to the input terminal of the primary side of the instrument transformer; and

a load side bushing, mounted on and insulated from the platform, for connecting a load side of the line to the output terminal of the primary side of the instrument transformer;

the secondary side of the instrument transformer reducing a magnitude of the parameter of the signals on the line and outputting monitoring signals;

the secondary side of the instrument transformer providing the monitoring signals to a monitoring apparatus;

wherein the monitoring apparatus is for monitoring the parameter of the signals that are carried on the line.

2. The portable monitoring apparatus of claim 1, wherein the instrument transformer is for reducing the magnitude of voltage of the signals.

3. The portable monitoring apparatus of claim 1, wherein the instrument transformer is for reducing the magnitude of current of the signals.

4. The portable monitoring apparatus of claim 1, wherein the line comprises a three phase line and wherein:

the instrument transformer comprises three instrument transformers for the three phases of the line, respectively;

the source side bushing comprises three source side bushings, for connecting the source side each of the three line phases to the input terminals of the primary side of the instrument transformer;

the load side bushing comprises three load side bushings, for connecting the load side of each of the three line phases to the output terminals of the primary side of the instrument transformer;

for metering each phase of the parameter.

5. The portable monitoring apparatus of claim 1, further comprising a fixed power transformer connected to the source conductor.

6. The portable monitoring apparatus of claim 1, further comprising a mobile sub-station transformer connected to the source conductor wherein the monitoring instrument is for monitoring an output of the mobile sub-station transformer.

7. The portable monitoring apparatus of claim 1, further comprising the monitoring instrument.

8. The portable monitoring apparatus of claim 7, wherein the monitoring instrument comprises an electrical revenue meter and the parameter comprises voltage and current.

9. The portable monitoring apparatus of claim 1, further comprising a remote terminal unit connected to monitoring instrument for providing remote control of the monitoring instrument.

10. The portable monitoring apparatus of claim 1, further comprising a recloser connected to the source side of the line for interrupting the supply of the signals to the load side of the line.

11. The portable monitoring apparatus of claim 1, further comprising a circuit breaker connected to the source side of the line for interrupting the supply of the signals to the load side of the line.

12. The portable monitoring apparatus of claim 1, further comprising a station service transformer for receiving the source side of the line and for outputting operating power.

13. The monitoring apparatus of claim 1, further comprising:

a source side insulator mounted on the platform for insulating the platform from the source side conductor; and

a load side insulator mounted on the platform for insulating the platform from the load side conductor.

14. The portable monitoring apparatus of claim 13, further comprising:

an electrically conductive grounding grid mounted on the platform, the grounding grid for grounding the load side insulator and the source side insulator;

an electrically conductive ground loop connected to the grounding grid, and to the instrument transformer, the ground loop for grounding the instrument transformer; and

a ground cable for connecting the grounding grid and the ground loop to an earth ground.

15. The monitoring apparatus of claim 1, wherein the platform comprises a trailer having wheels and wherein the source side bushing, the load side bushing, and the instrument transformer are mounted on the trailer.

16. The monitoring apparatus of claim 15, wherein the trailer further comprises a roof panel, a front panel, a rear panel, a source side panel, and a load side panel wherein the roof, front, source side, and load side panels form an enclosure within the trailer.

17. A method of connecting a trailer-mounted portable monitoring apparatus to a line in a power transmission or distribution network, comprising:

transporting the portable monitoring apparatus to the line at a point within the power transmission or distribution network;

electrically connecting a source side of the line to a first power bushing that is mounted onto the trailer and which is electrically isolated from the portable monitoring apparatus;

electrically connecting a load side of the line to a second power bushing that is mounted onto the trailer and which is electrically isolated from the portable monitoring apparatus;

grounding the portable monitoring apparatus; and

monitoring the line from monitored signals obtained through the source side of the line and passed through to the load side of the line.

18. The method of claim 17, wherein monitoring the line comprises metering power delivered to the load side of the line.

19. The method of claim 17, further comprising:

mechanically connecting the source side of the line to a first post insulator mounted on an electrically conducting grounding grid, the grounding grid being mounted on the portable monitoring apparatus; and

mechanically connecting the load side of the line to a second post insulator mounted on the electrically conducting grounding grid.

20. The method of claim 17, wherein connecting the source side of the line comprises connecting the first power bushing to a secondary side of a power transformer.

21. The method of claim 17, wherein connecting the source side of the line comprises connecting the first power bushing to a secondary side of a mobile power transformer.

22. The method of claim 17, further comprising:

electrically connecting the grounding grid to a grounding conductor; and

electrically connecting the grounding conductor to an earth ground.

23. The method of claim 17, wherein monitoring the line comprising coupling the monitored signals to a monitoring instrument.