1, Precautions
1. The temperature of the tested product should not be lower than+5 ℃, and the test should be conducted under good weather conditions with a relative humidity generally not exceeding 80%.
2. After the interruption of the test and the restoration of power supply, the continuous withstand voltage test should be repeated throughout the entire time period, and only the "time compensation" test should be conducted.
3. Pay attention to observing and monitoring the sound and phenomenon of the gap between the tested transformer and the protective ball, and analyze and distinguish related phenomena such as corona or discharge.
4. Before withstanding voltage, check whether the required power capacity and the capacity of the testing equipment meet the requirements.
2, Analysis of Test Results
1. After the communication withstand voltage test, other tests should also be combined, such as insulation resistance test before and after transformer withstand voltage (using high-voltage insulation tester), partial discharge test (using partial discharge test equipment), no-load characteristic test (using transformer no-load tester), insulation oil spectrum analysis (using transformer oil and gas analyzer), etc., to comprehensively judge whether the tested product has passed the test.
2. The testing mainly focuses on the instructions of monitoring instruments and listening to sound, with testing experience as a supplement.
3, Summary
1. External power frequency withstand voltage can effectively detect the following defects
Local defects, moisture, and cracks in the main insulation
Insufficient lead distance, loose winding
Impurities, bubbles, and dirty winding insulation in the oil
2. External frequency AC withstand voltage cannot detect the following defects
Longitudinal insulation strength
Phase insulation and partial neutral point insulation
Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test device) and has been engaged in the electrical measurement industry for many years. Its products have first-class quality and welcome customers to come and purchase.