A triggered co-ordinating gap for metalclad substations
Abstract
A triggered sphere gap in SF6 was developed to provide protection against switching overvoltages in metalclad substations. The trigger is activated when the voltage across the gap reaches a predetermined level, irrespective of its waveshape or polarity. Complete breakdown of the gap follows in 3 microsec due to delays in the triggering circuit, but there are prospects of reducing this. Protection against lightning surges at the basic insulation level is ensured by self-breakdown on the front of the wave. The protective level of the gap is well defined, the difference between the guaranteed withstand and flashover voltages being less than 2%. Since the gap must be replaced after each flashover, it should be used only where the probability of it operating is low. In those situations it could be considered as a small, low-cost alternative to a surge arrester.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- January 1978
- Bibcode:
- 1978STIN...7828360H
- Keywords:
-
- Electric Power Plants;
- Spark Gaps;
- Surges;
- Trigger Circuits;
- Capacitance Switches;
- Reliability;
- Switching Circuits;
- Electronics and Electrical Engineering