一种混压同塔四回线路跨电压故障的通用计算方法

A General Calculation Method for Cross-voltage Fault on Mixed-voltage Four-circuit Line on the Same Tower

从相分量支路阻抗方程出发,采用三序分量法推导了混压同塔四回线路模型解耦的方法,证明了线间互感只影响零序网络,进而推导了跨压模式下零序互感标么值的计算方法,从而维持了故障前网络基础数据模型节点阻抗标么值矩阵的对称性;研究了跨线故障的通用故障边界模型,为了适应混压问题,首先建立故障边界节点导纳有名值矩阵,提出了跨电压模式下计算故障边界导纳矩阵标么值的计算方法.进而基于补偿法求取故障口电流。算例分析验证了方法的正确性。所提方法可用于定值整定与在线校核软件。

Based on the phase component branch impedance equation,the decoupling method of the mixed-voltage four-circuit transmission line model on the same tower is deduced by using the three-sequence component method.It is proved that the mutual inductance between lines only affects the zero-sequence network,and the method for calculating the per unit value of the zero-sequence mutual inductance in the cross-voltage mode is deduced.The method maintains the symmetry of the node impedance matrix with unit values in the basic data model of the network before fault.Moreover,the universal fault boundary model for cross-line fault is studied.In order to adapt to the problem of mixed voltage,the actual admittance matrix of the fault boundary node is first established,and the calculation of its unit value in the cross-voltage mode is proposed.Then the fault current is calculated based on the compensation method.The example analysis shows that the proposed method is correct.The proposed method has been applied to the protection setting and online checking software.