Increase in voltage level and line length leads to a large distributed line capacitance which means that UHV lines have high reactive power requirements. To ensure reliable operation, common solution is fixed reactors are connected in parallel to the line. However, these fixed reactors cannot deal with overvoltage issues and reactive power requirements well at the same time which warrants need of advance FACTS devices such as STATCOM or SVC. To deal with these issues in an economical way, NARI Group CLP Purui Power Engineering Co., Ltd. (China Power Purui Technology Co., Ltd.) developed controllable UHV Shunt Reactor with rated voltage of 1100 kV and 600 Mvar. The advantage of Controllable UHV is that this capacity can be divided into three levels using the thyristor valves and capacity can be switched in 10 ms. This one of its kind device is installed at Jiading II line of the UHV Zhangjiakou Substation. Link to the news: