适应于酒泉风电送出的750kV线路纵联保护原理研究

A 750 kV transmission line pilot protection suitable to Jiuquan wind power base delivery

针对酒泉大规模风电基地送出750 kV输电线路,提出了一种适用于带串补和可控电抗器输电线路的故障分量综合阻抗纵联保护新原理。通过计算线路故障分量差动电压与差动电流的比值得到综合阻抗,外部故障时,综合阻抗反映线路的并联容抗,模值很大;内部故障时,综合阻抗反映系统阻抗,模值很小,并分析指出补偿相间电容后再分相计算综合阻抗判据,可以增强健全相保护的可靠性。新原理容易整定,本身具有选相能力,不受负荷波动、电容电流的影响,不受串补电容以及可控电抗器的影响,耐受过渡电阻能力强。利用ATP以酒泉风电基地750 kV送出系统为原型进行仿真实验,结果表明该原理可靠灵敏,适应于大规模风电送出工程的需要。

This paper presents a new pilot protection scheme based on fault component integrated impedance（FCII） for 750 kV transmission line with SC and TCR for Jiuquan wind power base.The FCII is the ratio of the sum of the fault component voltage phasor and the sum of the fault component current phasor of two terminals.It is used to identify if there is a fault on the line.If the fault is out of the line,the calculatio n value of FCII reflects the line capacitive impedance which has greater amplitude,and if the fault is on the line,it reflects the system impedance and line impedance which has relatively smaller amplitude.According to the amplitude of the FCII,the internal fault can be distinguished from external fault.Through compensating the capacity bet ween phases the reliability of the new scheme can be enhanced.The scheme can be set easily and has phase selection capacity,it is free from the influence of line load fluctuation,capacitive current,SC and TCR,and it can resist higher fault resistanc e.The effectiveness of the new scheme is verified by Jiuquan wind power 750 kV transmission system model and the new scheme is suitable to the large scale intermittent wind power delivery.