SYSTEM AND METHOD FOR MEASUREMENT OF PARTIAL DISCHARGE SIGNALS IN HIGH VOLTAGE APPARATUS

• US 20020014890A1
• Filed: 02/02/1998
• Published: 02/07/2002
• Est. Priority Date: 02/02/1998
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: COOKE, CHATHAN M.
• Granted Patent: US 6,420,879 B2
• Time in Patent Office: Days
• US Class Current: 324/536
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16
• CPC Class Codes: G01R 31/346 Testing of armature or field windings
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

A system is disclosed for monitoring electrical partial discharge signals in electrical power apparatus. The apparatus includes a housing and a plurality of openings in the housing through which electrical power may pass via electrical power contact units. The system includes a plurality of sensor units, each being in communication with, and associated with, an electrical power contact unit at each opening in the housing. The sensor units are for sensing partial discharge signals at each opening in the housing and for producing sensor output signals. The system also includes a control unit for simultaneously and synchronously receiving the sensor output signals over an interval of time, and produces simultaneous synchronous output signals. The system also includes a processing unit for processing the simultaneous synchronous output signals.

Claims

1. A system for monitoring electrical partial discharge signals in electrical power apparatus including a housing and a plurality of openings in said housing through which electrical power may pass via electrical power contact units, said system comprising:

a plurality of sensor means, each being in communication with, and associated with, an electrical power contact unit at each opening in said housing, for simultaneously and synchronously sensing partial discharge signals at each opening in said housing and for producing sensor output signals;

control means for simultaneously and synchronously receiving said sensor output signals over an interval of time, and for producing simultaneous synchronous output signals; and

processing means for processing said simultaneous synchronous output signals.

2. A system as claimed in claim 1, wherein said sensor output signals are representative of the amplitude and frequency of a partial discharge signal for said interval of time.

3. A system as claimed in claim 1, wherein said sensors are broadband sensors.

4. A system as claimed in claim 1, wherein said electrical power apparatus is a power transformer and said electrical power contact units are bushings.

5. A system as claimed in claim 1, wherein said processing means includes filter means for distinguishing between discharge signals originating outside of said housing, from discharge signals originating inside said housing.

6. A system as claimed in claim 1, wherein said processing means includes means for determining the general location inside of said housing from which a partial discharge has originated.

7. A system as claimed in claim 1, wherein said sensor means each include a capacitive tap, a high frequency sensor, and a cable extending between said capacitive tap and said high frequency sensor.

8. A system as claimed in claim 7, wherein said cables associated with each sensor means are all of approximately equal length.

9. A system as claimed in claim 7, wherein said control means includes means for establishing variance signals representative of the differences in length among the cables of the sensor means, and further includes means for producing said simultaneous synchronous output signals responsive to said variance signals.

10. A method of monitoring electrical partial discharges in electrical power apparatus including a housing and a plurality of openings in said housing through which electrical power may pass via electrical power contact units;

said method comprising the steps of;

simultaneously and synchronously measuring partial discharge signals at each of said contact units at each of said housing openings; and

processing said simultaneous and synchronous partial discharge signals to discern characteristics of said partial discharges.

11. A method as claimed in claim 10, wherein said step of simultaneously and synchronously measuring said partial discharge signals includes adjusting for differences in the time required for a signal to travel from each of said electrical power contact units to a high frequency sensor.