Study On Space Charge Measurement System Of Polymer Insulation

The polymer insulation materials have being widely used in the electric insulation field for its easy processing, good dielectric and thermal performance. However, the space charge are always accumulated in insulation materials for the residual charge in the production processes, high voltage injection or polarization caused by the impurity of the material, etc. Because space charge plays an important role in polymers ageing process, it has attracted much concern around the world. It has great relationship with trap in the insulation materials. The space charge not only makes the electric field distortion but also reflect the dielectric conductance, electrode emission, charge migration, neutralization and the variable density of trap. So, the space charge studying makes the micro-perspective of the polymer material varied with the ageing process possible. Furthermore, it can promote the development of aging and breakdown theory of the polymer insulation.This thesis works on the space charge measurement system for the polymer insulation materials. First, a thermally stimulated current (TSC) measurement system with high precision, good anti-interference and high automatic level is developed. Then the test method is investigated and the total quantity of the space charge and the activation energy are calculated. Second, a space charge distribution measurement system based on Pulsed Electro-acoustic method (PEA) is developed after the resolution and sensitivity analysis. The space charge distribution under polarization and short-circuit conditions are measured individually. According to the measurement results, the space charge distribution characteristic is analyzed and calibrated.All the work the thesis introduced provides a method to measure both the total quantity and space charge distribution. And it is also the basis of the space charge study.