Power Frequency Withstand Test Wiring for Fully Insulated Voltage Transformers

To conduct a power frequency withstand test, first prepare a test set consisting of a testing transformer and an operating console. The two red output wires on the console connect to the input of the step-up transformer. The blue wire connects to the return instrument, and the black wire is the grounding wire, which must be securely grounded. Then, connect the top of the step-up transformer to the high-voltage terminal of the voltage transformer, and short-circuit the two high-voltage terminals of the voltage transformer. This part of the wiring must be suspended in the air (floating). Finally, short-circuit all terminals on the secondary side of the transformer and connect them to the grounding busbar through a grounding wire. Now, the voltage can be raised to 80% of the factory test voltage to complete the withstand test.