Synchronization of generator

Synchronization of generators should done if it is connected to the National Grid. Before connecting a generator to the National Grid started generator should connect to the Synchronize cope then it should synchronize with the use of speed varying knob. Although the speed of the generator will vary by rotating the speed varying knob, after generator connect to the grid speed does not vary but the current drawn from generator to the grid will vary.

Auto Transfer Switch (ATS)

ATS is two big relays that use to connect main power supply or generator power to the load. To prevent two relays operate at a same time there is a mechanical lock between two relays also it prevent closing one relay while operating another relay. Although there is mechanical lock between two relays they will not energize at a same time by the Auto Mains Failure (AMF) board, lock will be useful it same malfunction will occur.

Main Parts of the Lifts

Machine room
Motor
Lift car
Counter Weight
Over-speed governor
Traveling cable
Brake
Loading entrance
Lift well
Lift pit

Oil Circuit Breaker

The arrangement permits two advantages firstly the current breaking chamber requires a small volume of oil which is just enough for arc excitation secondly, the amount of oil to be replaced as the in the supporting chamber does not get contaminated the arc.
The single phase oil circuit breaker, there are only one moving contact. But HTM branch dehiwala has three phase oil circuit breaker. There are six moving contacts. Their supporting chamber and circuit breaking chamber made having metal. But single phase OCB supporting chamber made porcelain. Three phase OCBis very heavily we can’t moving it very easily.

Earth Fault Protection

• Earth fault current may be limited.

• Sensitivity and speed requirement may not be met by over current relays.

• Use separate earth fault relay

• Connect to measure residual (zero sequence) current.

• There fore can be set to values less than full load current.

Generator Protection

Generator protection

* Over current protection
* Short circuit current protection
* Earth fault protection
* Differential Current protection
* High voltage Protection
* Under voltage protection
* Under frequency protection
* Over Frequency protection
* Reverse power protection

Mainly Genarator set can be divided into two part

1. Engine
2. Alternator