Real-time transient security assessment in Australia at NEMMCO

The Australian National Electricity Market Management Company (NEMMCO) uses a variety of tools to assess the real-time security of its power system. NEMMCO and the transmission network service providers are particularly concerned with dynamic security. In addition to power system damping monitors used to measure the system oscillatory damping characteristics, NEMMCO has developed a real-time transient security assessment tool. The state estimator solution is sent to a time domain simulation engine, which monitors the transient stability of the power system for a number of credible contingencies. It was important to use commonly used standard power system analysis tools to help build confidence in the tool amongst the various planning bodies. The tool has proven invaluable in alerting and preventing insecure operation whilst the power system is under abnormal operating conditions. Both the approach and the computational architecture are described. In addition, a number of implementation issues, from the telemetered data, through the state estimation and model conversion, to the analysis phases are addressed.