双TCR支路型TCSC基波阻抗特性和控制策略仿真研究

为了满足电力系统对特高压线路可控性和安全性的要求,可以在特高压线路上加装TCSC(Thyristor Controlled Series Capacitor)。而特高压的高电压和大电流对TCSC造成了考验,即大幅度提高TCSC的额定电流时,流过晶闸管阀支路的电流随之增加,有可能超过晶闸管的通流能力极限。提出在单TCR(Thyristor Controlled Reactor)支路型TCSC结构上,再增加一条TCR支路实现对大电流分流。TCR支路增加了控制复杂性,首先由于阀控电抗器的制造误差、测量误差等的存在,会引起流过两条TCR支路电流不均流,严重时损坏阀体,故需要增加均流的控制措施;其次阻抗表是TCSC实现阻抗跟踪的基础,计及均流要求的阻抗解析算法复杂度高。在研究双TCR型TCSC基波阻抗特性的基础上,提出了求取阻抗表的简便方法。

Fundamental impedance characteristics and control strategy for TCSC with dual-TCR branches

In order to satisfy the controllability and security requirement for power systems,the TCSC(Thyristor Controlled Series Capacitor) is installed on the UHV(Ultra High Voltage) line.The UHV and high current become the challenge to TCSC,i.e.with the substantial increase of the rated current of the TCSC,the current flowing through the thyristor branch should also be improved,which may exceed the current limit of thyristor.A TCSC scheme with an extra TCR branch in parallel is proposed,which can shunt the large current.The dual TCRs will inevitably increase the control complexity.Firstly the manufacturing error and measurement error of valve-controlled reactor will make the current between the two TCR branches not equal,which will damage the thyristor in severe conditions,therefore current-balancing control is needed.Secondly,the impedance table is the basis for TCSC control.Considering current-balancing characteristics of dual TCRs,the analytical algorithm of impedance table of TCSC with both TCRs is complicated.On the basis of studying of impedance characteristics of dual TCRs,a simple method is proposed to describe the impedance table.