The tap changer is typically located inside the transformer tank or in a separate compartment, depending on the transformer design and the type of tap changer. On most standard utility grade padmount transformers, tap changers are located in the primary HV cabinet of the transformer.
Here's a breakdown of its location:
1.Internal Tap Changer (Inside the Transformer Tank):
- Most commonly, the tap changer is located inside the main transformer tank , immersed in the same insulating oil as the transformer windings.
- It is physically connected to the transformer windings to allow changes in the number of turns.
- This design is typical for On-Load Tap Changers (OLTC) and some off-load tap changers.
2. External Tap Changer (Separate Compartment):
- In some transformers, especially larger ones, the tap changer may be housed in a separate compartment outside the main tank but still connected to the windings.
- This design allows for easier maintenance and reduces the risk of contamination of the main transformer oil.
- The separate compartment is also filled with insulating oil.
3. Location on the Windings:
- The tap changer is connected to the high-voltage (HV) winding in most power transformers because the HV side has more turns, making it easier to achieve fine voltage adjustments.
- However, in some cases, it may be connected to the low-voltage (LV) winding, depending on the transformer design and application.