Isolator is a manually operated mechanical switch which separates a part of the electrical power system normally at off load condition.
A complete live closed circuit must not be opened by isolator operation and also a live circuit must not be closed and completed by isolator operation to avoid huge arcing in between isolator contacts. That is why isolators must be open after circuit breaker is open and these must be closed before circuit breaker is closed. Isolator can be operated by hand locally as well as by motorized mechanism from remote position.
Motorized operation arrangement costs more compared to hand operation; hence decision must be taken before choosing an isolator for system whether hand operated or motor operated economically optimum for the system. For voltages up to 145KV system hand operated isolators are used whereas for higher voltage systems like 245 KV or 420 KV and above motorized isolators are used.
TYPES OF ISOLATOR
SEC Engineering sales a wide range of reliable and energy efficient disconnectors to meet the requirements of different sites and network conditions. The disconnectors range from 72.5 kV to 550 kV. disconnectors range from 72.5 kV to 550 kV. The largest of its kind in India produces double break, centre break and pantograph isolators and maintenance earth switches upto 420KV/3150A.
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