Implementation of the Single Machine Equivalent (SIME) Method for Transient Stability Assessment in DIgSILENT PowerFactory

The development of novel smart transmission grid applications has recently gained deep interest based on the fact that there has been a wide deployment of technology capable of controlling the system in real time. In fact, some smart grid applications have been designed in order to perform timely Self-Healing and adaptive reconfiguration actions based on system-wide analysis, with the objective of reducing the risk of power system blackouts. In this new framework, real-time vulnerability assessment has to be firstly done in order to decide and coordinate the appropriate preventive or corrective control actions, such as special protection schemes. Since transient stability is, indeed, one of the most critical causes of system vulnerability, developing and applying assessment methodologies capable of delivering quick responses is fundamental among this smart structure. In this connection, a hybrid method, named Single Machine Equivalent (SIME), seems to present good perspectives of application for orienting both preventive control actions (off-line simulations) or corrective control actions (real-time analysis: emergency SIME). This method uses a combination of time-domain signals together with the equal area criterion (EAC) in order to determine the transient stability status based on the computation of stability margins. One of the challenges regarding the application of the SIME method is to adequately integrate it with a time-domain solver routine (such as the one already implemented in DIgSILENT PowerFactory). In this connection, this chapter addresses key aspects concerning the implementation of SIME by using DIgSILENT Programming Language (DPL). An application example on a well-known benchmark power system is then presented and discussed in order to highlight the feasibility and effectiveness of this implementation in DIgSILENT PowerFactory environment.