Modeling Analysis and Measurement of Power Frequency Overvoltage Distribution of Long-Distance Transmission Cable

With the continuous expansion of urban power transmission and distribution scale, long-distance transmission cable lines are widely used. Compared with short distance cable lines, long distance cable lines have more overvoltage problems; At the same time, the existing over-voltage standards and protection measures for long-distance overhead lines are not applicable to long-distance cable lines, so it is of great significance to analyze the power frequency overvoltage distribution law of long-distance cable lines and conduct real-time monitoring. Firstly, a typical 220kV cross-linked polyethylene (XLPE) cable simulation model is established based on PSCAD simulation software. Then, the power frequency overvoltage distribution characteristics of long-distance cable lines are studied and analyzed. Finally, on-site tests are carried out using a non-contact measurement device. The results show that the power frequency overvoltage caused by single-phase ground fault is high; The power frequency overvoltage can be reduced by reducing the cable section or laying the cable in trefoil shape; There is a positive correlation between the cable length and the sheath induced voltage. The on-site test further proves that the simulation model is accurate and the non-contact overvoltage measurement device is feasible.