Analysis and Application of On\|line Measurement of Dielectric Loss Angle Based on Synthetic Relative Measuring Method

Synthetic relative measuring method not only overcomes the shortcomings of absolute measuring method but also greatly improves the accuracy of dielectric loss angle measurement. However, researches nowadays only focus on the application of synthetic relative measuring method based on two or three pieces of capacitive equipment, which does not have the characteristic of generality. The principle of synthetic relative measuring method is given. The example of application for synthetic relative method based on three and four pieces of capacitive equipment installed in the same phase is taken and by induction some failure judgment matrices used to judge the insulation condition of i(1≤i≤N) of N(N≥3) pieces of equipment are presented, which provides theoretical foundation for its application. Actually, the insulation condition of the capacitive equipment could not be judged only according to whether the value of relative dielectric loss angle happens to change or not, so two diagnostic methods based on synthetic relative measuring method and some facts that influence the correct diagnosis of the method are proposed, which provides a guideline for actual use of the method.