Research And Design For System Of Insulation Resistance Measurement With Insulator DC

The reliable and safe operation of the electrical equipment in power system is deeply affected by the insulation level of the equipment and the voltage set on the insulation. With the rapid development of the national economy, the rising of the electrical system voltage caused by the increasing of the electricity consumption and the lengthening of the transmission distance made the problem of the electrical equipment insulation more and more serious. This article focused on the study and research of the Resistance measurement of the insulator.This paper is based on an actual enterprise project. With research of a large number of references both home and onboard, we have a detailed analysis and research on DC insulation resistance measurement technology of insulators, and complete the system of DC insulation resistance measurement of insulators. The system is composed by software system and hardware system. The software system is designed by VB development platform and SQL Server2000 database management system. The hardware system is composed by PEC8000 type PLC and ZGF-60 type portable DC high voltage generator. PLC collects voltage and current signals, and then transfers to PC using MODBUS protocol.After analysis of the characteristics of the insulator, we get a conclusion that insulator is a capacitive load. The capacitive load will cause the measured current signal having harmonic components, and affect the resistance calculations. To solve this problem, we select three kinds of filtering algorithm and make simulation and comparison. Based on the results, we selected mean limiting filter. Historical data show that the filtering algorithm can fully guarantee the accuracy of measurement.After on-site installation and commissioning, the system passed the test and had been running for more than one year. The system works stably and meets the design requirements.