考虑电容电流影响的广域电流差动保护

为避免广域电流差动保护受电容电流影响而误动的情况发生,通过对传统电流差动保护进行改进,提出一种不受电容电流影响的广域电流差动保护算法。利用微分方程计算出各线路上的电容电流,采用修正的差动电流对暂态和稳态电容电流进行有效补偿,即在传统差动电流基础上减去计算出的电容电流以使电流差动保护不再受电容电流的影响。利用PSCAD仿真实验将改进的广域电流差动保护与传统原理的电流差动保护进行了比较。结果表明,该保护不受电容电流影响,外部故障时可靠不动作,验证了此保护算法的可行性和有效性。

Wide area current differential protection considering the effects of capacitive current

To avoid the circumstances that the maloperation currently occurs when the wide-area current differential protection is influenced by the capacitive current, this paper improves the traditional current differential protection and puts forward a way to calculate the wide-area current differential protection that is not affected by capacitive current. We use differential equation to calculate the capacitive current on different circuits, and by using amendatory differential current, we make efficient compensation for fault transient current and steady capacitive current. That is to guarantee current differential protection against the influence from capacitive current, we subtract the calculated capacitive current from the traditional differential current. The PSCAD simulation experiment compares this protection with the traditional current differential protection. It turns out that this protection is not affected by capacitive current, and has no maloperation through external failure, which verifies the feasibility and effectiveness of this protective calculation.