Research On The Monitoring Methodology Of Metal Oxide Surge Arrester Insulation Defects

Metal Oxide Surge Arrester (MOA) is the power system over-voltage equipment that can provide better protection levels and greater protective margin. Its operation reliability will directly influence the safe operation of the power system. As the MOA to withstand long-term system voltage, over-voltage, dirt, interal moisture and other factors,its insulation properties Which may lead to equipment failure, the impact of power system security, stability and reliability. Therefore,it has tremendous economic and social benefits to study monitoring method,find and debug hidden faults to prevent the occurrence of such malignant accidents. Therefore, it has important theoretical and practical value to study monitoring method and find and debug hidden faults to prevent the occurrence of such malignant accidents.This paper introduces the background and significance of the monitoring method of the Metal Oxide Arrester. The current research status of monitoring methods is reviewed in this paper. The principles and advantages of several insulation online monitoring methods of the Metal Oxide Arrester are analyzed and compared in this paper. Based on studying the electrical characteristics of the valves, the equivalent circuit, each of the characteristic quantities and the impact factors of online monitoring, This paper presents an on-line monitoring methodology based on transient voltage and current. This method takes the oscillating wave voltage and current which is caused by load switching, reclosure and failure in the power system as the signal source, structures the discriminant function of monitoring and diagnostics and generates extremum sequence about the discrimination function. The discriminant function is a comprehensive criterion. It monitors and diagnoses insulation defects by the correlation coefficient which is the result by comparing with the reference data sets. This method does not just compare the t harmonic current amplitude of fundamental current and three times harmonic cuttent. Thus it has good anti-interference ability and fault tolerance. This method diagnoses the location and severity of the insulation defects according to the maximum value of the discriminant function. Therefore, it has good anti-interference ability and fault tolerance. This paper conducts ATP simulation and laboratory tests to verify this method. The results confirm the validity and reliability of this method.In this paper,this on-line monitoring method based on the oscilating voltage and current which can be measured from the measuring terminal, does not require an external signal source, discriminant Jane bomb, easy implementation,strong operability, contribute to the MOA deterioration in insulation monitoring technology application and development.