In-service evaluation of motor and generator stator windings using partial discharge tests

Journal Article · Wed Mar 01 04:00:00 EST 1995 · IEEE Transactions on Industry Applications

DOI:https://doi.org/10.1109/28.370277· OSTI ID:51718

Stone, G C ^[1]; Sedding, H G ^[2]

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1. IRIS Power Engineering, Mississauga, Ontario (Canada)
2. Ontario Hydro, Toronto, Ontario (Canada)

Partial discharges (corona) are a symptom of most types of deterioration of motor and generator stator windings rated 4 kV and above. Experience indicates that partial discharges occur years before failure. This leaves sufficient time to plan corrective maintenance to avoid the in-service failure of the motor or generator. This paper describes a new type of partial discharge test which can be performed by plant personnel during normal operation of the machine, thus enabling all users of large machines to plan maintenance. The key requirement of the new test is to remove all the interference caused by other sparking and discharging sources in a plant. Such noise has lead to false indications of stator winding deterioration in the past. The new test uses either high-voltage capacitive sensors, high-frequency current transformers, or 1,000-MHz electromagnetic couplers to detect the discharge signals. These signals are processed on a pulse-by-pulse basis by a specialized electronic instrument to remove noise and the remaining partial discharges are then categorized according to number, magnitude, and phase position. The test has been implemented on over 100 machines, and the results appear promising.

• OSTI ID: 51718
• Journal Information: IEEE Transactions on Industry Applications, Journal Name: IEEE Transactions on Industry Applications Journal Issue: 2 Vol. 31; ISSN 0093-9994; ISSN ITIACR
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
ELECTRIC ARCS
ELECTRIC GENERATORS
ELECTRIC MOTORS
ELECTRICAL FAULTS
ELECTRICAL TESTING
MAINTENANCE
REPAIR
STATORS