APT Automatic Paralleling Switchgear can be used in Prime Power or an Emergency Power applications which requires operation of multiple generators in parallel.
Automatic Paralleling Switchgear Features:
Upon receipt of an automatic start signal initiated locally by the operator or remotely by customer’s SCADA RTU (via closure of a dry contact), the switchgear shall issue a start signal to the generator set. At that time, generator set’s speed shall be controlled by the switchgear. Generator voltage shall be determined by the voltage adjust potentiometer. If the bus is dead and other conditions are appropriate, then the first generator to build up voltage and frequency shall close its synchronizing circuit breaker, energizing the bus. If the load bus is already energized, then the generator set shall be automatically synchronized with the load bus under the supervision of the dedicated synchronizing check relay. When all the synchronizing conditions are met the synchronizing circuit breaker shall close. At that time, the generator set shall operate as an isochronous load sharing machine. Real load (kW) and reactive load (kVAR) shall be shared proportionally with other generator sets connected to the load bus.
Upon receipt of an automatic stop signal initiated locally by the operator or remotely by customer SCADA or DCS system (via closure of a dry contact) the switchgear shall automatically open the circuit breaker and shutdown the generator set after a cool down period.
The switchgear shall also include provisions for manual operation.
In case of bus overload multiple stage load shed capability shall be provided. Non-critical loads feeder circuit breakers shall be tripped and/or form “C” dry type contacts will be provided for each stage of load shedding to disconnect non critical loads downstream from the switchgear.
Load shed ON – OFF/RESET switch shall be provided as part of the system.
Time delays for each stage of load shed shall be adjustable through the operator interface unit mounted on the door