A Transformer Tap Changer is a device used in power transformers to adjust the voltage levels of the transformer's secondary winding. Its primary purpose is to regulate the output voltage so that it matches the desired voltage level required by the connected electrical system or load. This helps to maintain a stable and consistent voltage supply and ensures proper functioning of the electrical equipment and devices connected to the transformer.
The tap changer operates on the secondary winding of the transformer and is usually placed on the high-voltage side. It allows the number of turns in the secondary winding to be adjusted, which, in turn, changes the turns ratio between the primary and secondary windings. This adjustment effectively changes the output voltage level without altering the primary voltage.
There are two main types of tap changers:
On-Load Tap Changer (OLTC): An on-load tap changer is designed to adjust the voltage while the transformer is energized and under load. It allows for voltage adjustments without interrupting the power supply. OLTCs are commonly used in applications where voltage variations in the electrical grid or demand fluctuations require continuous adjustments.
Off-Circuit Tap Changer (OCTC): An off-circuit tap changer is designed to change the tap position when the transformer is de-energized or disconnected from the load. This type of tap changer is more suited for applications where voltage adjustments are infrequent and can be made during scheduled maintenance or shutdowns.
The tap changer typically has multiple tap positions (taps) along the secondary winding. Each tap corresponds to a specific number of turns on the winding. When the tap position is changed, the effective turns ratio of the transformer alters, resulting in a different output voltage level.
The control mechanism of the tap changer can be manual, automatic, or remotely operated. Some modern transformers use sophisticated automatic tap changers that are capable of responding to voltage fluctuations and grid conditions in real-time to maintain a stable output voltage.
In summary, the Transformer Tap Changer is a vital component in power transformers, allowing for voltage adjustments to match the required output voltage and ensure reliable and efficient operation of the electrical system.