STATCOM control with Robust synchronizing phase locked loop under three phase power system faults

摘要

The STATCOM (synchronous static compensator) based on voltage source converter (VSC) has gained wide attentions due to its outstanding performance and is used for voltage regulation in transmission and distribution systems. It can supply dynamic VAR's all over system faults for voltage support. The STATCOM operation can be adversely affected to voltage source converter (VSC) over-currents and trips, during power system faults when it's dynamic VAR support functionality is most required. The normal PLL (Phase-locked Loop) in the system, which tracks positives sequence information of bus voltage, but fail to track negative-sequence bus voltage during system faults. In this paper, we build up an STATCOM with Robust PLL. Robust synchronizing PLL tracks exact information under any fault conditions This constraint of implementing STATCOM with robust PLL, results in avoiding over-currents and trips of the STATCOM during and after system faults, and enable that the STATCOM to supply required reactive power when it is most required support most required. Simulation results are presented for a 48-pulse VSC based 100 MVAR STATCOM connected to a 2-bus power system.