On-load Tap Changing Transformers (OLTC)
The main features of an on-load tap changing transformer are the selector switches, reactors, vacuum switch and a bypass switch. The selector switches select the tap position and cannot make or break the load current. The reactors increase the support of the selector circuit and restrain the amount of current rotating because of the high voltage.
Because the transformer allows for a tap-change, the selector switches can be selected to different taps and the current will circulate into the reactor circuit. The vacuum switch of the transformer provides the duty to the circuit breaker that can make or break the current during the tap changing process. The bypass switch, however, it doesn’t make or break the load. It does make the connections before breaking the connections.
- Up to 50 MVA
- Up to 138 kV
- Up to 650 kV BIL
- Single Phase or Three-Phase
- 55⁰C, 65⁰C, Others
- Copper or Aluminum
- Circular Disc, Circular Layer, Rectangular Layer
- Type Switches: Vacuum or Resistive
- Seismic Zone: Up to 4
- Ambient Temperature Range: -40⁰C to +40⁰C
- Standards: C57.12.10, C57.12.00, IEC