Recognition and pricing of the generators contribution to the network voltage support in a market environment

The paper deals with a very crucial ancillary service required for the transmission network voltage support by generators: the so called ldquovoltage servicerdquo (VS). In a competitive electricity market, the dispatchers are pushed to achieve reliable operation standards, so they have to manage the voltage service in a way to warrant adequate covering of the system demand also under perturbed or congested operating conditions, offering to the customers increased quality, security and economy of the electrical energy supply. According to that, the voltage duty is examined with reference to relevant aspects such as: The contribution of wide area voltage regulation system allowing a very effective voltage service, with a simple and inexpensive operational effort; the costs and benefits related to the voltage service to be considered in the transmission tariff; the way to guaranteeing a correct economical recognition of the contribution to network voltage support given by each generator, a pricing criteria for the voltage service; and the perspective of a centralized operation, supervision and accounting of the VS supplied and consumed. In this last framework, the paper also discuss the complex problem of the correct measure and computing of the power plant contribution to the network voltage regulation, showing the criticism of the present generalized situation where the generators efforts in terms of reactive power delivery/absorption is not generally representative of their concrete contribution to the network voltage support. The paper also shows the simplicity, correctness and indubitableness of indicators of the generators contribution to network voltage support, in case the considered generators operate under secondary voltage regulation (SVR).