The tap changer includes on load tap changers ( OLTC or LTC) and De-Energized Tap Changer (DETC).On-load tap changer (OLTC), also known as On-circuit tap changer (OCTC); De-energized tap changer, also known as Off-circuit tap changer (OCTC) or No-load tap changer (NLTC).
1. On-Load Tap Changers (OLTC)
On-load tap changers, also known as OLTCs, are designed to change the transformer’s tap settings while it is energized and under load. OLTCs use various mechanisms, such as diverter switches and selector switches, to alter the transformer’s winding connections. This allows for voltage adjustments to compensate for fluctuations in the power grid, ensuring a steady supply of electricity.
OLTCs are commonly found in substation transformers, where voltage adjustments are frequently required to accommodate changing loads and voltage profiles.
2. De-Energized Tap Changers (DETC)
Unlike OLTCs, de-energized tap changers are designed to switch the transformer’s taps when it is de-energized or offline. They do not require complex switching mechanisms since they operate under no load conditions.
DETCs are used in substation, pad mounted, and pole mounted transformers (distribution transformers). They are ideal for making tap changes during scheduled maintenance or when the transformer is out of service.
