In what scenarios are VLF, variable-frequency series resonant, and power-frequency withstand voltage tests respectively suitable? During high-voltage testing, clients often encounter three types of AC withstand voltage tests: Very Low Frequency (VLF), variable-frequency series resonant, and power-frequency withstand voltage tests. While all three can be used for insulation withstand testing,…

How to Choose Between 30kV, 50kV, 60kV, 80kV, and 90kV VLF High-Voltage Generators？ When selecting a Very Low Frequency (VLF) high-voltage generator, customers often ask: "Should I choose 30kV, 50kV, 60kV, 80kV, or 90kV?" Answering this question requires more than just looking at whether the cable is rated for 10kV…

Can VLF (Very Low Frequency) withstand voltage testing be used for 10kV and 35kV cables? Yes. VLF withstand voltage testing can be applied to 10kV and 35kV power cables, provided that the test plan, equipment voltage rating, load-bearing capacity, and on-site operational procedures comply with relevant standards. VLF withstand voltage…

Why is an ultra-low frequency high voltage generator commonly used for voltage withstand tests on 10kV cables? In the voltage withstand verification after 10kV cable handover tests, preventive tests, and fault repairs, many sites utilize 0.1Hz ultra-low frequency high-voltage generators. Compared to traditional power frequency voltage withstand equipment, ultra-low frequency…

Why measure the DC resistance of transformer windings? The DC resistance test for transformer windings is a crucial component of both factory acceptance tests and maintenance inspections; it is primarily used to verify the integrity of the winding's conductive path and the reliability of its connections. Measuring DC resistance allows…

How should testing equipment for 10 kV transformers be configured? The configuration of testing equipment for 10 kV transformers cannot be determined solely by the voltage rating; it must be decided based on a comprehensive assessment of transformer capacity, product type, specific test items, testing volume, and on-site power supply…

What factory tests are required for dry-type transformers? Upon completion of manufacturing, dry-type transformers must undergo factory tests to inspect the windings, core, insulation system, and accessory functions, ensuring that product performance meets design specifications, relevant standards, and the customer's technical agreement. Common factory tests for dry-type transformers include the…

What power supply capacity is required for a transformer test bench? There is no single, fixed value for the power supply capacity required by a transformer test bench; it must be determined based on a combination of factors, including the capacity and voltage class of the transformer under test, the…

Both power-frequency withstand voltage testing and induced withstand voltage testing are critical insulation tests for transformers, yet they differ in their testing methods, the specific insulation being checked, and their objectives. Simply put, the power-frequency withstand voltage test primarily checks the main insulation (between windings and ground, and between windings…

What does a non-compliant short-circuit impedance indicate? Short-circuit impedance is a key performance parameter of a transformer, primarily reflecting the winding structure, leakage magnetic field distribution, and the ability to limit short-circuit current. A non-compliant test result usually indicates anomalies in winding design, manufacturing/assembly, or testing conditions. 1. Deviations in…