Towards a risk-based network operation and design standards

In principle, a electricity transmission network security standard that is established within a risk-based framework is superior over the deterministic approach, usually presented in the form of an N-k type rule, as it balances more accurately the reliability (and other) benefits against operation and investment costs incurred to deliver these benefits. However, in the absence of advance technology to monitor, predict, simulate and control large-scale networks in real time, deterministic standards have historically delivered a successful operation of massive and complex electric networks. However, nowadays through the usage of new technology such as Special Protection Schemes (SPS), coordinated voltage control technique, wide-area monitoring and control systems (WAMC), Dynamic Security Assessment techniques (DSA), grid friendly controllers for Demand Side Management (DSM) etc, there is a genuine possibility to apply a probabilistic framework for network security. A risk-based framework will not only maximise the value of transmission but also speed up the connections of wind power. Through qualitative analyses we point out various problems of the present deterministic standards in the UK together with identifying key benefits at a regulatory and operational level of implementing a probabilistic standard. In addition, through quantitative analyses we show that current deterministic standards significantly overvalue reliability risks and, in fact, a probabilistic cost-benefit framework can lead to important savings in the cost of constraints without significantly increasing the risk of system interruptions.