A fault-tolerant P-Q decoupled control scheme for static synchronous series compensator

Control of nonlinear devices in power systems relies on the availability and the quality of sensor measurements. Measurements can be corrupted or interrupted due to sensor failure, broken or bad connections, bad communication, or malfunction of some hardware or software (referred to as missing sensor measurements in this paper). This paper proposes a fault-tolerant control scheme (FTCS) for a static synchronous series compensator (SSSC). This FTCS consists of a sensor evaluation and (missing sensor) restoration scheme (SERS) cascaded with a P-Q decoupled control scheme (PQDC). It is able to provide effective control to the SSSC when single or multiple crucial sensor measurements are unavailable. Simulation studies are carried out to examine the validity of the proposed FTCS. During the simulations, single and multiple phase current sensors are assumed to be missing, respectively. Results show that the SERS restores the missing data correctly during steady and transient states, including small and large disturbances, and unbalanced three-phase operation. Thus, the FTCS continuously provides effective control to the SSSC with and without missing sensor measurements.