Validation of a STATCOM Transient Stability Model through Small-Disturbance Stability Studies

Synchronous STATic COMpensator (STATCOM) controllers are being more prevalently used to address some voltage and angle stability and control problems, especially in distribution systems with the advent of microgrids. Thus, this paper discusses the validity of a typical transient stability (TS) model of a STATCOM widely used in small-disturbance stability studies of large, interconnected power grids as well as microgrids. EMTDC/PSCAD-based time domain simulations for both TS and detailed models, with a standard control and a supplementary control, are used as the basis for comparison and validation. A system identification technique, i.e. the Prony method, is applied to the time domain signals to extract relevant electromechanical mode information, illustrating that, under certain conditions, typical STATCOM TS models can yield too optimistic results, which may lead to errors in power system planning and operation.