计及直流分压器传变特性的行波保护定值整定方法

Setting Method of Traveling Wave Protection Considering Transfer Characteristics of DC Voltage Divider

行波保护作为特高压直流输电系统线路的主保护,其动作的准确性直接关系到直流输电系统的安全稳定运行。行波保护各判据中故障特征量的生成均基于直流分压器的测量值。然而,直流分压器难以准确地传递各频段下的信号,这将导致行波保护的可靠性下降。首先,基于直流分压器等效电路模型推导直流分压器传递函数,分析直流分压器对时域信号及频域信号的传变特性。其次,结合行波保护的判据和逻辑,研究直流分压器传变特性对行波保护性能的影响。然后,将直流分压器传变特性作为影响行波保护定值整定的因素纳入整定流程,提出一种计及直流分压器传变特性的行波保护定值整定方法。最后,参照实际工程参数搭建仿真模型,对所提方法的有效性及可靠性进行验证。结果表明,所提方法能有效提高行波保护整定的可靠性。

Travelling wave protection is the main protection for the transmission line of the ultra high voltage direct current(UHVDC) transmission system, and its operation accuracy is directly related to the safe and stable operation of the DC transmission system. The generation of the fault characteristic quantity in each criterion of the travelling wave protection is based on the measured value of the DC voltage divider. However, the DC voltage divider is difficult to accurately transfer the signal at every frequency band, which leads to the decrease of the reliability of traveling wave protection. Firstly, the transfer function of the DC voltage divider is derived based on the equivalent circuit model of the DC voltage divider, and the transfer characteristics of the DC voltage divider to signals in the time domain and frequency domain are analyzed. Secondly, combining the criterion and logic of traveling wave protection, the influence of the transfer characteristics of the DC voltage divider on the performance of the traveling wave protection is studied. Then, the transfer characteristics of the DC voltage divider are incorporated into the setting process as a factor which affects the setting of the traveling wave protection, and a setting method of traveling wave protection considering the transfer characteristics of the DC voltage divider is proposed. Finally, a simulation model concerning actual engineering parameters is built to verify the effectiveness and reliability of the proposed method. The results show that the proposed method can effectively improve the reliability of the traveling wave protection setting.