中文摘要：

为提高变压器式可控电抗器的工作效率，对绕组电流进行了分析。为此，基于顺次单支路工作模式下的绕组分级原则，在考虑所有绕组白、互漏抗影响的基础上，推导出了不同工作状态下的绕组电流、额定电流利用率与等效漏抗的函数关系，并给出了能使电抗器高效工作的等效漏抗设计要求。通过算例说明等效漏抗会影响控制绕组电流的分配，导致额定电流利用率低下，并由此提出电抗器设计需满足“小漏抗”原则。结果表明，当等效漏抗小于由功率递增级数、绕组额定电流利用率设计值、第1级控制绕组容量比、绕组个数及短路电抗确定的最大值时，控制绕组额定电流利用率可以满足设计要求，即变压器式可控电抗器可工作于高效状态。

英文摘要：

In order to improve the efficiency of controllable reactor of transformer type, we analyzed the winding current. Based on the grading principle of step-single-branch operation mode, taking the self and mutual leakage reactance of all windings into account, we derive the functions of winding current, rated current utilization and equivalent leakage reac- tance, and propose a requirement in equivalent leakage to make the reactor efficient. Meanwhile, through an example, we demonstrate that the equivalent leakage reactance influences the winding current distribution and lowers the rated current utilization, so the design of reactors should follow the principle of minimizing leakage reactance. Some other conclusions are also drawn： the current utilization would fulfill the design requirement when the equivalent leakage reactance is less than the maximum value that is determined by the power increment coefficient, the required utilization of rated current, the capacity ratio of the first level control winding, the winding number, and the short-circuit reactance. In this case, the controllable reactor of transformer type could work efficiently.