Research On The Problems Of The Over-voltage Monitoring System Based On The Transfer Characteristics Of Potential Transformer

In the modern power systems, the phenomenon of over-voltage often occurs because of the lightning strike, failure, resonance, switching operation, etc. As soon as running across the over-voltage, the electrical equipments during operation are likely to generate breakdown, discharge, flashover, explosion accident and so on. These accidents cause not only economic loss of power companies but also serious effect on the security and stability of the power network. Therefore, monitor and analysis of the over-voltage of the power system is of great significance to ensure the security and stability of the power network.This paper combines with the "Chinese Universities Scientific Fund" funded projects and the project "the research of overvoltage on-line monitoring system based on the Transfer Characteristics of Potential Transformer" of Jinzhong power supply company of Shanxi. In the basis of antecessor’s achievement, the problems emerge in the process of the development are researched. The main work and results of this study are summarized as follows:(1) The influence of signal transmission caused by interphase inference of secondary cable. Adopting EMTP-ATP sofeware, first, we estable the simulated model of secondary cable; Second, the voltage of inference can be known though simulating; Final, the experiment plat is set up in the laboratory; the comparison between the experiment results and the simulated results confirms the correctness and effectiveness of the simulaton.(2) The effect of signal acquisition results from secondary equipment. Adopting the method of combining simulation with experiment, first, we estable the experiment model and research the influence of the signal acquisition caused by secondary equipment. Moreover, the siuation of the long cable also be researched.(3) The preliminary analysis of the voltage monitoring method based on CVT. We estable the experiment plat, set up the calculated model, and analysis this mothed’s possibility through combining expeiment with simulation. Contrary to the problem of numerical oscillation problem in the process of time-domain inversion, the analysis is conducted with aspects of the parameter of voltage divider, the fitting of transmission parameters and calculated method error, and these analysis and conclusion make significant contributions for resolving the problem of numerical oscillation.