Why insulation absorptance is used to measure the insulation absorptance of power equipment?
The absorption ratio refers to the ratio of the insulation resistance value of 60s to the insulation resistance value of 15s at the same time when the DC voltage is measured with an insulated shake table or an insulation resistance tester.
Some insulation objects (such as: plastic, porcelain etc.) under DC voltage, the conduction current instant can reach a stable value, but for generators, transformers, motors, cables and other electrical equipment, which is composed of composite insulation medium in DC voltage, will produce a variety of polarization phenomenon. At the beginning of the polarization, the current is very large. With the increase of the compression time, the current value drops and the insulation resistance increases accordingly. This phenomenon is called absorption phenomenon.
The insulation resistance reflects only the steady state value of the measurement, but the absorption ratio can reflect the value of the measurement process. The purpose of measuring the absorption ratio is to find the insulation damp. In addition to reflecting the damp condition of the insulation, the absorption ratio can also reflect the overall and local defects. It is more sensitive than simply measuring the insulation resistance.
