Moisture External Applied Voltage Test Transformer Voltage Regulator Sphere Gap Voltage Divider



Table Test Item Core Equipment Auxiliary/Supporting Equipment Function Insulation Resistance/Absorption Ratio Megohmmeter (2500V/5000V) None Preliminary check for insulation moisture DC Resistance DC Resistance Tester None Check winding welding quality, tap changer contact condition Turns Ratio and Vector Group Turns Ratio Tester None Verify turns ratio and connection group correctness Dielectric Loss (tanδ) Dielectric Loss Tester (Bridge) Standard Capacitor Judge overall insulation aging, moisture External Applied Voltage Test Transformer + Voltage Regulator Sphere Gap, Voltage Divider, Microammeter Assess main insulation strength Induced Overvoltage + Partial Discharge Triple Frequency Power Supply + Corona-Free Test Transformer Partial Discharge Tester, Coupling Capacitor Assess longitudinal insulation and detect internal defects No-Load/Load Characteristics Power Analyzer / High Current Generator Voltage Regulator Measure loss parameters Protection Verification Microcomputer Relay Protection Tester None Verify transformer protection device logic 3. Key Selection Tips If you are purchasing a test transformer for transformer testing, please be sure to confirm the following parameters to avoid buying the wrong one: Voltage Level Matching: The output voltage must be higher than the test voltage standard of the transformer under test (e.g., for testing a 10kV transformer, the withstand voltage standard is usually 35kV or 28kV, it is recommended to choose 50kV or higher for margin). Capacity Calculation: The transformer is mainly a capacitive load during the withstand voltage test. Estimation formula: