CAJ | 학술논문

针对大停电事故中距离保护因过负荷误动的问题，通过比较电压平面和阻抗平面上的过负荷特征，提出了基于电压平面的距离保护应对过负荷策略。本策略分2部分：基于Ucosφ的过负荷与相间故障识别方法，过负荷时 Ucosφ较大，相间故障时 Ucosφ较小；基于正序补偿电压和相补偿电压相位特征的过负荷与单相接地故障识别方法，单相经过渡电阻接地故障时，正序补偿电压超前相补偿电压相位，线路过负荷时，正序补偿电压与相补偿电压相位一致。根据上述特征实现了过负荷与故障的区分，避免了距离保护因过负荷误动。
침대대정전사고중거리보호인과부하오동적문제，통과비교전압평면화조항평면상적과부하특정，제출료기우전압평면적거리보호응대과부하책략。본책략분2부분：기우Ucosφ적과부하여상간고장식별방법，과부하시 Ucosφ교대，상간고장시 Ucosφ교소；기우정서보상전압화상보상전압상위특정적과부하여단상접지고장식별방법，단상경과도전조접지고장시，정서보상전압초전상보상전압상위，선로과부하시，정서보상전압여상보상전압상위일치。근거상술특정실현료과부하여고장적구분，피면료거리보호인과부하오동。
In allusion to the malfunction of distance protection caused by overload during large-scale blackout, through comparing the fault features on voltage plane and impedance plane a voltage plane based strategy of distance protection to cope with the overload is proposed. The proposed strategy is divided into two parts: one of them is the Ucosφbased method to identify overload and phase-to-phase faults, since the value of Ucosφ is smaller under the overload condition and larger under the fault condition; the another of them is a method to distinguish single-phase earth fault from the overload, which is based on the phase characteristics of positive-sequence compensated voltage and that of phase compensated voltage, for single-phase earth fault via transition resistance, the phase of the positive-sequence compensated voltage leads to that of the phase compensated voltage, and for the overload the phase of the positive-sequence compensated voltage is consistent with that of phase compensated voltage. Based on above-mentioned features the overload can be distinguished from grid faults and the malfunction of distance protection due to the overload can be avoided.