A Static Synchronous Compensator (STATCOM), one of Flexible AC Transmission Systems(FACTS), is gaining more ground in the utility and industrial market. By adopting Modular Multilevel Converter(MMC) technology and overcoming its disadvantage such as losses, it is becoming more
efficient and a better solution for utilities, industrial customers, renewable business, and so on.
This paper introduces a way of the testing and evaluation of a MMC STATCOM controller. The first
part presents the development and testing of MMC valves. This includes the developments of the fullbridge submodule and the MMC valves composed of them, and the corresponding operation and
current loading tests. The tests include the rated and overloaded current load testing using a test circuit,
which has 2 MMC valves, and an AC power supply. Before testing the real MMC values, the HILS
using RTDS was utilized in order to confirm the control and protection schemes by various test
scenarios. Therefore, the possibility of causing any damage on the MMC values from any potential
error was reduced.
The second part of this paper delves into the details of the Hardware In-the-Loop Simulation (HILS)
for the control & protection systems of STATCOM station using RTDS (Real-Time Digital Simulator).
One of the available MMC simulation models, namely ‘ChainV5’ model, in RSCAD/RTDS was
utilized for the purpose of establishing more realistic HILS testing environment in real time. The
external controller under the test was connected with the real time simulation running in RTDS
through analogue output and input cards(GTAO and GTDI) and interface boards developed for HILS.
This testing composition enabled us to verify the protection function of phase & submodule controllers,
such as forced submodule outage, as well as their control functions. Other control & protection system
components were connected with GTAO cards, thus they were able to receive analogue signals like
getting the CTs & PTs signals in real system.
Finally, this paper concludes with the HILS testing results. We were able check the correct operation
of the control.
J. Park, Y. Park, D. Lee, S. Yeo, D. Lee, I. Park, Presented at the CIGRÉ Canada Conference on Power Systems, Winnipeg, Canada, Sep. 2015., paper CIGRE 599
KEYWORDS: Modular Multilevel Converter, STATCOM, RTDS, Hardware In the Loop Simulation (HILS)