为了使静止同步补偿器(static synchronous compensator，STATCOM)控制系统具有灵活的扩展性、灵活的信息配置功能、高速的传送速率、极短的数据交换时间以及精确的时钟同步，提出了一种用于链式STATCOM的基于EtherCAT总线技术的控制系统。该控制系统采用2个EtherCAT总线网：（1）主控网采用串型通讯方式，从站有数据采集从站、开入开出从站、调节保护从站和暂态故障记录从站；（2）模块网采用星型通讯方式，所有从站经耦合器引出，从站有调节保护从站、暂态故障记录从站以及所有模块从站。调节保护从站和暂态故障记录从站都隶属于2个EtherCAT总线网。该控制系统在调节保护从站、暂态故障记录从站以及所有模块从站中均使用数字信号处理器（digital signals processor，DSP）实现控制，可显著提高信号传输速度和控制速度，能够满足实时控制要求。实验结果表明，该控制系统极大提高了装置的扩展性、配置功能、传输率，达到了精确的同步，可应用于链式STATCOM及其他采用链式换流器的柔性交流输电（flexible AC transmission systems，FACTS）装置中，具有控制目的明确、易于实现、控制效果稳定等特点。

This paper put forward a control system of static synchronous compensator (STATCOM) based on the EtherCAT bus technology, which had the characteristics of flexible expandability, Flexible information allocation function, high transfer rate, very short data exchange time, and accurate synchronized clock. The control system used two EtherCAT bus nets: main control net and module net. The main control net adopted series communication mode, and had data sample slave, data input and data output slave, regulation and protection slave, and transient fault record slave in the main control net. The module net adopts stelliform communication mode, and all slaves are derived from the couples. There are regulation protection slave, transient fault record slave, and all module slaves in the module net. The regulation protection slave and the transient fault record slave belonged to two EtherCAT bus nets. Digital signals processor (DSP) was used in the regulation protection slave, the transient fault record slave and the module slaves, which could improved signal transmission and control speed, and meet the requirements of real-time control. The experiment results show that the control system can significantly increase the device expandability, allocation function and transfer rate, achieve precise synchronization. The control system can be applied in the chain STATCOM and other flexible AC transmission systems (FACTS) used chain converter, which has the characteristics of clear control purposes, easy to implement and stable control effect.