How is the insulation level of a transformer evaluated and defined?
Today we will explain how to determine the insulation level of a transformer. The reason for explaining this content is that the insulation level of a transformer is a standard for assessing the quality of a transformer. Therefore, as a transformer manufacturer, it is necessary to explain it to you for detailed selection in the future. Before introducing the identification method, we need to understand that the insulation level is generally evaluated by measuring a set of rated withstand voltages.
Here is one of our manufacturer's testing methods for this area. Generally, we have three measurement methods:
① Using power frequency rated withstand voltage tests (including external withstand voltage tests and induced withstand voltage tests), combined with measuring local discharge capacity, to assess insulation reliability under long-term operating voltage;
② Using an impulse voltage generator to simulate lightning overvoltage after lightning protection restrictions, conducting lightning impulse tests to assess the ability of transformer insulation to withstand lightning overvoltage;
③ Using an impulse voltage generator to generate a feasible and representative operating wave, conducting an operational impulse test to verify the ability of the high-voltage winding insulation to withstand operating overvoltage of transformers with voltage levels not less than 330kV.
The above is the measurement and distribution commonly used by transformer manufacturers. In fact, in order to ensure good quality, transformer manufacturers
Two test voltage levels are specified for transformers of the same voltage level. The power frequency withstand voltage test of transformers is the main method for inspecting the insulation state of transformers at the time of leaving the factory.
When purchasing, the general roundness is usually high or low, but if the measurement is still from low, it can ensure the stable quality of the transformer.
The above is our knowledge introduction.
