【摘要】 分析了变压器发生区内外故障时差流和制动电流的异步变化规律,提出了变压器差动保护新算法。以端电压序分量的大小和变化趋势作为比率差动的闭锁条件,选取小于1个周波的数据窗计算相关电压值。仿真试验表明新算法不受励磁涌流、和应涌流的影响,当发生区内略微严重故障时可在10~15ms内快速动作,发生区外故障时不会误动,对大型高压/超高压变压器能够起到快速保护作用,具有较高的实用价值。更多还原

【Abstract】 The asynchronous varying rules of differentialcurrent and breaking current are analyzed while internal orexternal fault of transformer occurs, and a new algorithm, i.e.,the high-speed ratio differential protection algorithm, fortransformer current differential protection is proposed. Takingthe magnitudes and varying trends of sequential components ofterminal voltage as restraint condition of ratio differentialprotection, the asynchronous rule of the differential current andbreaking current, which are the basis of the proposed algorithmare found out while faults occur, and a data window narrowerthan one cycle is chosen for the calculation of relevant valuesof voltages. Simulation results show that the proposedalgorithm is not affected by inrush current or sympatheticcurrent; by use of this algorithm the protection can quickly actwithin the time duration from 10ms to 15ms under a littleserious internal fault of transformer as well as it will notmisoperate under external fault, thus the high-speed protectionfor high capacity HV/UHV transformers can be implemented.更多还原