Ensuring Operational Security in Power Systems with Large Amount of Renewable Generation

摘要

In power systems with high share of renewable generation new ways to ensure reliability of supply have to be found, at not only infrastructure level but also at the control level. To be able to back up intermittent supply from wind and photovoltaic power plants, conventional generation has to be very flexible and more intelligent local and wide-area control schemes have to be developed and implemented. A power application tool can be established to increase situational awareness of dispatchers in the control room. By that dangerously developing conditions can be recognized in their early and be given priority attention. This paper provides a brief technical insight in the components of such power application. Based on a snapshot from EMS/SCADA the actual system state is analyzed under contingencies and what-if scenarios, and with respect to stead-state and dynamic limits. By using a modern computer system this can be done very fast and with great accuracy. Moreover, the same investigations can also be conducted for future real and hypothetical states considering a very short-term (e.g. 30 min) wind forecast and load fluctuations. An example is included, that shows possible control room integration and on-line use of the system. Moreover, also a simulation example is given how more than 1000 dynamic contingencies can be calculated faster than in real time, which is a typical nowadays requirement The paper also addresses the practical value of such an approach. The major features are highlighted through a report on first experiences that a European transmission system operator has made while using the tool during testing in 2011/2012. The testing period consisted of two phases of nine months each. The objective was not only to gain experiences with the technical features and performance of the tool with respect to requirements of off-line and online stability assessment, but also to evaluate its usability and usefulness to the dispatcher. During the first phase, the application was in system planning (off-line). The focus was on modeling validation, computational performance, and accuracy of stability assessment algorithms. The second phase included coupling with SCADA/EMS and examination of online capabilities.