Estimation of Zero-Sequence Impedance Parameters in Double-Circuit Lines Using Disturbance Recorder Data

Knowledge of accurate zero-sequence line impedance parameters of transmission lines is critical for power system engineers since they play a key role in the settings of distance and directional protection relays, and fault location applications. Double-circuit transmission lines involve zero-sequence mutual impedance due to mutual coupling between the conductors, in addition to the self-impedance. The paper presents an offline estimation technique for zero-sequence self and mutual impedance parameters for double-circuit transmission lines using data from disturbance recorders from both terminals. The most accurate distributed parameter line model is used, and simulation tests prove the accuracy of the algorithm. The application of zero-sequence mutual coupling compensation in distance protection of double-circuit lines using the estimated parameters is also presented.