Composite membranes for fluid separations
Closing resistors in EHV circuit breakers are frequently used to reduce switching transients on lines thus preventing flashovers during line energization. Maintenance and failures of such closing resistors can be costly and reduce transmission system reliability. For these reasons, APS conducted an investigation into the technical feasibility of operating its 500 kV without closing resistors. This patent describes study results of removing closing resistors from 500 kV breakers in a system which employs older technology silicon carbide type surge arresters. The paper also describes results of field tests of the expected flashover rates calculated in the study. These field tests involve repeatedly energizing a 258 mile 500 kV line using a breaker in which the closing resistors are disabled. Transient overvoltages captured during the tests are compared with predicted overvoltages. The study concludes that closing resistors may be removed from the subject system without unacceptable consequences.
- Assignee:
- Membrane Technology and Research Inc., Menlo Park, CA (United States)
- Patent Number(s):
- US 4990255; A
- Application Number:
- PPN: US 7-516181
- OSTI ID:
- 7115533
- Country of Publication:
- United States
- Language:
- English
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