科研之友
微信
新浪微博
Facebook
分享链接
摘要
Power-frequency parameters of long-distance extreme-high-voltage (EHV) and ultra-high-voltage (UHV) transmission lines are the basis of power system modelling and analysis, but these parameters are especially difficult to accurately measure due to the reactance-dominated nature and strong external interference. An accurate power-frequency parameter measurement approach is proposed in this study. The idea is to utilise frequency response curve to indirectly extrapolate transmission line parameters at power frequency. As no direct measurement is conducted at power frequency, the potential power-frequency interference is avoided. A resonance-based measurement method is employed to eliminate the effect of large impedance phase angle of EHV/UHV systems and identify positive-and zero-sequence resistance with enhanced accuracy. In order to validate the effectiveness of the proposed approach, a prototype instrument was developed and used to measure power-frequency parameters of a scale-down laboratory transmission line system. Comparative results confirmed the accuracy priority of the proposed approach over existing power-frequency measurement methods. In addition, the anti-interference performance in terms of the impact of the parallel in-service transmission line also indicates the proposed approach is more advantageous as it has lower capacity requirement on the measurement device.
