Understanding Tap Changers:-
Tap changers are essential components in transformers, used to regulate voltage by altering the transformer winding ratios. They are commonly found in high-voltage transformers like those used in power substations, ensuring voltage stability across the grid.
There are two main types of tap changers:-
- On-Load Tap Changers (OLTC): –
These can operate while the transformer is under load, making them crucial for continuous voltage regulation.
2.Off-Load Tap Changers (NLTC):-
These can only be adjusted when the transformer is de-energized.
Maintenance Criteria:- During the maintenance process, I learned that tap changer servicing is typically triggered by four key factors:
High Operation Count: When the tap changer exceeds 100,000 operations.
Extended Time in Service: If the tap changer has been in operation for more than 7 years.
Oil Quality Concerns: If yearly Breakdown Voltage (BDV) values fall below 33 kV or if the oil’s moisture content exceeds 12 ppm.
PRD (Pressure Relief Device) Maintenance: This safety device, which prevents excessive pressure build-up within the transformer, requires regular inspection and servicing to ensure it operates correctly during fault conditions
Maintenance Procedures:- The maintenance process involved a thorough inspection and testing of various components:-
Contact Switches:– We measured the parameters to assess their condition.
Resistor Banks:- Resistance measurements were taken to ensure they were within specified limits, crucial for the proper operation of the tap changer.
