Research On Fault Diagnosis Algorithms Of Lightning Protection On-line Monitoring System For Power Supply

The Metal Zinc Oxide Arrester(MOA)not only has excellent nonlinear but also has high good protection performance. The inner moistened, aging of MOA will lead to increasing of the leakage current of resistive even exploding or selfignite under the working voltage for a long time, finally, an accident of power system may occur. Therefore, in order to find out the hidden trouble, online monitoring of the MOA is necessary, and then we can understand its running state in real time, which can provide safeguard for the safe operation of power system.Its resistive current will significantly increase because of the hidden trouble and the anomalies of MOA, so the resistive current of MOA is the main object of monitoring. At present, there is a variety of monitoring resistive current methods at home and abroad, but the process of monitoring is usually affected by the interference of the harmonic voltage and the interphase coupling capacitance, due to the influence of the two kinds of interference, the measured result has certain deviation.In order to solve the problem, the monitoring principle of LCD-4 monitor is analyzed and the improvement of capacitive current compensation method is researched, finally,the voltage zero software analysis method is analyzed and researched. Not only does the method successfully eliminate the interference brought by harmonic voltage and interphase coupling capacitance in the power system in the process of the resistive current on-line monitoring, but also it makes the monitoring data becoming more precise. The formula of the method was derived in detail in this paper and the reliability of the method is verified by simulation, at the same time, by comparison with the data of the improvement of capacitive current compensation method, it proves that this method has higher precision.