Towards an integrated approach to the valuation of secured real and reactive power deliveries

Transmission system operators secure the real-time deliveries of real and reactive power through the coordinated supply of ancillary services in the form of voltage and frequency control services. In the case of frequency control, previous work demonstrated the inherent coupling between the pre- and post-contingency states which must be taken into account when securing real power deliveries. Theoretical results indicate that marginal costs for energy and security can be derived if one takes those couplings into account. This paper goes beyond and considers the further cross-couplings imposed by the need to deliver securely and concurrently both real and reactive power. We extend the fundamental result on marginal cost of secured real power delivery in deriving marginal value formulae for joint real and reactive power deliveries.