多并联支路型可控电抗器短路电抗对支路电抗和电流的影响

Short-Circuit Reactances of a Controllable Reactor of Multi-Parallel Branch Type's Influence on Its Branch Reactances and Currents

短路电抗对支路电抗和电流的影响是造成多并联支路型可控电抗器(Controllable Reactor of Multi-parallel Branch Type,CRMB)支路电抗和电流额定值的选取困难、以及设备利用率下降的重要原因。根据CRMB各支路晶闸管依次导通和关断的工作特点,采用递推算法求得了CRMB支路电抗和电流的计算公式。对这些计算公式的函数分析和算例分析后指出,支路电抗随着短路电抗的增大而减小;支路电流额定值随着短路阻抗的增大而增大,而其支路电流额定值利用率最小值随着短路电抗的增大而减小;为了提高CRMB设备利用率,CRMB短路电抗应小于一个由电流额定值利用率的最小值、CRMB支路容量递增系数和支路数决定的最大值,由此可以选取短路电抗、支路电抗和电流的设计额定值。研究结论可为CRMB的工程设计和变压器式可控电抗器的研究提供理论参考。

The impact of the short-circuit reactance on the branch reactance and current is the important reason which causes a difficulty to select the branch reactance and current ratings of a controllable reactor of multi-parallel branch type(CRMB), and the decline in equipment utilization. According to the each branch thyristor working characteristics of orderly turn-on and turn-off, the CRMB branch reactance and the current calculation formulae are derived by the recursive algorithm. After the function analysis on the calculation formulae and the calculation of an example, it is pointed out that the branch reactances decrease with transformer short-circuit reactance increasing, the branch currents increase with transformer short-circuit reactance increasing and the utilization rate minimum of a branch current rated value decreases with transformer short-circuit reactance increasing. In order to improve the utilization rate of CRMB equipments, the short-circuit reactance of the power transformer of CRMB should be less than a maximum value determined by the rated current utilization rate minimum, the branch capacity increment coefficient and the branch number. Therefore the design ratings of the transformer short-circuit reactance, branch reactance and current of a CRMB are selected. The results of the paper can be used as the theoretical foundation for the future design of CRMB and the research on a controllable reactor of transformer type.