Distance Protection Setting Scheme for the Loss of Main Protection in High-Voltage Power Grid

With the continuous construction and development of high-voltage power grids, strategies such as dual redundancy configuration of main protection have been proposed successively to ensure reliable operation of the protection. However, certain abnormal conditions, such as loss of communication power supply, failure of both main protection channels, total station DC power loss (due to fire, etc.), theoretically cannot be completely ruled out in terms of their potential occurrence. According to the power system operation regulations, when the main protection is lost, it is necessary to trip the line, which affects the normal operation of the power grid and disrupts production and daily life. Therefore, a distance protection setting scheme for the loss of main protection in high-voltage power grids has been proposed. When abnormal operating conditions occur, the proposed scheme defines the emergency protection boundary and identifies the protective devices that require protection value modifications. Following the proposed principles, necessary adjustments will be made to the setting values of these protective devices. Using PSCAD/EMTDC to construct a simulation model, the simulation results demonstrate that the proposed distance protection setting scheme in this paper does not require additional protective devices and effectively ensures the safe operation of the power grid under abnormal operating conditions.