Application of Synthetic Relative Measuring Method in On-Line Monitoring for Capacitive Equipment

On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power system. Synthetic relative measuring method not only markedly overcomes the shortcomings of traditional absolute measuring method but also greatly improves the accuracy of dielectric loss angle measurement. However, the papers 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. In the paper, 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 run in the same phase is taken to present the failure judgment matrices for N pieces of equipment. According to these matrices, the fault condition of N pieces of capacitive equipment can be watched, which is more general. Finally some problems needing attention and two diagnostic methods used in diagnostic system are put forward in the paper to guide the application of synthetic relative measuring method on local. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC).