High-voltage surge arresters are important devices for limiting system overvoltage and protecting electrical equipment. This state is directly related to the safe operation of the high-voltage arrester itself and other electrical equipment. Preventive testing of high-voltage arresters is particularly important. The test of DC 1mA reference voltage (initial operating voltage) and 0.75u1ma leakage current of high-voltage arresters is an important part of the preventive test of high-voltage arresters. In the past, 220kV and 500kV high-voltage arresters used the test method of removing the conductors. When removing the 500kV high-voltage arrester leads, the workload is heavy. The wire is high from the ground, has a thick diameter, and is heavy. Disassembly and connection require sufficient manpower and lifting machinery, which is extremely inconvenient and easily broken and damaged. Disassembly and assembly once a year also has a great impact on the service life of the wires. At the same time, there are safety hazards at work, which brings unsafe factors to the maintenance work in spring and autumn. In order to solve these problems, we explored and studied the feasibility of lead-free testing. Through analysis and experiments, we mastered the method of connecting a resistance meter and a microammeter in series without removing the leads, and accurately measured the DC reference voltage and leakage current of the 220kV and 500kV high-voltage arresters. Since the 220kV high-voltage arrester has two sections, one section is smaller than the 500kV high-voltage arrester, the measurement method is relatively simple. Taking the 500kV high-voltage arrester test method without removing the leads as an example, the analysis was carried out.
Lightning arrester manufacturer
Test methods for high-voltage arresters without removing the leads:
1. High voltage surge arrester test conditions and characteristics
High voltage surge arrester test conditions without removing the leads
Without removing the leads, the status of each column of high-voltage arresters is the top of the upper and lower high-voltage arresters, and BCD is the bottom of the high-voltage arrester.
2. Characteristics of high voltage arrester
Under the operating voltage, the high-voltage arrester is actually equivalent to an insulator. Its volt-ampere characteristics can be small current region, nonlinear region and saturation region. The area where the current is lower than 1mA is a small current area, and the nonlinear coefficient a is high. In this area, as the voltage increases, the current will rise slowly. The current is typically non-linear between 1mA and 3KA with lower a. If the current in this area increases slightly, the current will rise sharply. When the current is greater than 3KA, it generally enters the saturation zone. As the voltage increases, the current will slowly rise
3. Method to measure the DC reference voltage and leakage current of high-voltage arrester without removing the leads
Measure the DC reference voltage and leakage current of the high-voltage arrester in sections to better test the models of the upper and lower high-voltage arresters, and then use the series resistance method to measure the middle section of the high-voltage arrester. In order to solve the problem of measuring the DC reference voltage and leakage current of the middle section of the high-voltage arrester, which is the key to testing without removing the 500kV high-voltage arrester lead, we use the method of series resistance at the bottom of the next section of high-voltage arrester to conduct real-time tests
Metal oxide arrester
