Transformer Dielectric Loss Tester

A: To measure the Dielectric Loss Factor (tan δ)​ and Capacitance (Cx)​ of insulation in transformers, bushings, and other HV equipment to detect moisture, aging, or contamination.

A:  GST (Grounded Specimen Test):​ Use this when the test object's metal tank/frame is grounded (e.g., testing a transformer bushing with the tank grounded).

UST (Ungrounded Specimen Test):​ Use this when the test object is isolated from ground (e.g., testing a bushing removed from the transformer).

A: Strong electromagnetic interference from nearby live equipment is affecting the measurement. Ensure the test object is fully de-energized and isolated. Use the instrument's anti-interference mode​ (e.g., automatic frequency shift) and keep test leads away from other power cables.

A: Yes, but you must use the correct mode.​ Use GST mode​ if the transformer tank is grounded. You must connect the test leads properly: HV to the bushing top, Cx cable to the bushing tap, and ensure the tank is grounded.

A: The safety check has detected an incomplete or high-resistance ground connection. Power down and check that both the instrument's ground terminal and the test object's ground (for GST) are securely connected to a reliable earth ground.