STATCOM ETO Failure Analysis

Abstract

Emitter Turn-Off (ETO) Thyristor based STATic synchronous COMpensator (STATCOM) is one of the promising Flexible AC Transmission System (FACTS) technologies, and it is gaining more popularity in utility grids. A 4.5 MVA ETO based STATCOM failed two ETO devices as over-voltage protection triggered AC connector and disconnected the STATCOM from AC grid supply. This paper presents the investigation of ETO failure reasons. The investigation found that dead time of switching signals is very critical for ETO applications. Protection methods for high power ETO applications are proposed based on failure investigation. Experiments verified the proposed protection method.