*Article* **Individual Phase Full-Power Testing Method for High-Power STATCOM**

#### **Qingjun Huang \*, Bo Li, Yanjun Tan, Xinguo Mao, Siguo Zhu and Yuan Zhu**

State Key Laboratory of Disaster Prevention and Reduction for Power Grid Transmission and Distribution Equipment, State Grid Hunan Electric Company Limited Disaster Prevention and Reduction Center, Changsha 410129, China

**\*** Correspondence: huangqj@hust.edu.cn; Tel.: +86-0731-86332088

Received: 28 May 2019; Accepted: 29 June 2019; Published: 4 July 2019

**Abstract:** For a high-power static synchronous compensator (STATCOM), a full-power pre-operation test in the factory is necessary to ensure the product quality of a newly manufactured one. But owing to the hardware limitation and cost of test platform, such test is currently too difficult to conduct in the factory, thus it poses grea<sup>t</sup> risk to the on-site operation and commissioning. To address this issue, this paper proposes an individual phase full-power testing method for STATCOM. By changing the port connection, three-phase STATCOM was reconstructed into a structure that two phases are in parallel and then in series with the third-phase, and then connected to two phases of the rated voltage grid. Then by rationally matching the voltage and current of three phases, the parallel phases can ge<sup>t</sup> a reactive current hedging under both the rated voltage and rated current, meanwhile three phases maintain their active power balance. As a result, STATCOM gets a phase full-power tested phase by phase. The simulation results in Matlab/Simulink show that, under the proposed test system, both the voltage and current of the parallel two phases ge<sup>t</sup> their rated values while the grid current is only about 3% of the rated current, meanwhile the DC-link voltage of each phase converter is stabilized. Compared with other testing methods for STATCOM, this method requires neither extra hardware nor high-capacity power supply to construct the test platform, but it can simultaneously examine both the entire main circuit and a large part of the control system in STATCOM. Therefore, it provides a cost-effective engineering method for the factory test of high-power STATCOM.

**Keywords:** full-power testing; high-power; individual phase; operation test; static synchronous compensator (STATCOM)
