Measurement and analysis of insulation resistance of lightning test grounding device based on applied DC excitation

In lightning tests, the safety of the insulation between grounding devices used in the test equipment is a key condition to ensure the smooth progress of the test.In the traditional insulation resistance testing method, high voltage instruments such as insulation gauges have the problem of no reading display at low resolution, so how to quantitatively evaluate the electrical isolation effect between grounding devices under safe low voltage testing conditions has become an urgent research.The team took the DC resistance value between grounding devices as the evaluation index of electrical isolation effect, and proposed a class of external DC excitation test method, and the consistency test showed that the resistance value measured by this method was accurate and stable. Based on a large number of sample specimen data obtained from the field significance test analysis, this resistance value does not change with time migration; with the addition of excitation has nothing to do; with the grounding device area, buried depth is negatively correlated; with the medium resistivity is positively correlated. Through the orthogonal experimental design of finite element simulation simulation, simulation results and field measurements of the law is consistent. The conclusions obtained are of guiding significance for the evaluation and optimization of technical means related to the measurement of electrical isolation between grounding devices in subsequent lightning tests.