Security Constrained Optimal Reactive Dispatch using GB Transmission Network Models

Security constrained optimal VAR despatch using 3500 bus Great Britain transmission planning models is investigated in this paper. The investigation demonstrates the value of applying practical reactive branch flow constraints to generator transformers in order to limit the pre-fault reactive utilization. This research also demonstrates that a multi-staged optimization approach can be used to remove constraint violations created by the discretization of controls. Optimization studies based on this method using Great Britain network models indicate that an average theoretical loss reduction of 1.4% is achievable, equivalent to the annual emissions of 45,000 tonnes of carbon dioxide. Relative to the corresponding real-time system snapshot these optimizations also achieved a reactive power utilization saving of 30.4%. These studies were constrained by around 800 credible contingencies and voltage limits, consistent with the National Electricity Transmission System Security and Quality of Supply Standards (NETSSQSS).