自耦补偿与谐波屏蔽换流变压器的接线方案和原理研究

针对传统换流变压器和滤波方式存在的问题,对一种新型的自耦补偿与谐波屏蔽换流变压器进行研究.该换流变压器阀侧绕组采用延边三角形接线,为3倍次谐波电流提供通路;通过匝比配合,实现12脉波换流;其延边绕组与公共绕组构成自耦变压器接线,可减少换流器换向时的电流冲击;在公共绕组上连接滤波支路,并调至谐振点,配之以变压器巧妙的零阻抗设计,可以在阀侧实现无功补偿,可实现网侧绕组中无5、7、11、13次特征谐波,即谐波屏蔽.仿真结果表明论文的理论分析正确;这种新型换流变压器可大大减少网侧绕组中的谐波含量,降低谐波在变压器中引起的损耗和噪音,同时可降低换流变压器的设计容量和绝缘设计的难度,将有很好的应用前景.

Principle and Connection Scheme of Self-Coupled Compensating and Suppressing Harmonic Converter Transformers

Aiming at the problems existing in the traditional converter transformers and filter scheme,this article does research on a novel self-coupled compensating and suppressing harmonic converter transformer (SCCSHCT). The windings in the valve side adopt prolonged delta connection providing the circuit for three-multiple harmonic currents,and implementing 12-pulse converter through fit ratio; this connection between the common winding and prolonged winding can decrease the current impact when phase conversion takes place. Connect the filter branch with the common windings,adjust L,C to the resonant point,and design the zero equivalent impedance of common windings,then it can compensate some reactive power and suppress effectively 5th,7th,11th and 13th characteristic harmonic currents concerned at the valve side. At last,the simulating results show that the theoretical analysis is correct. The content of harmonics at the net side of the novel converter transformers is greatly decreased,and also the losses and the noise caused by harmonic currents,as well as the design capability and the design difficulty of insulation are reduced.