An approach for allocating VAR service in the electricity market against voltage collapse

This paper presents an approach for procuring VAR service from the generators and synchronous condensers in a competitive market-based environment, where the transmission operator "TO" is supposed to run this market and enter in long-term contracts with the successful candidates to provide the required VAR whenever called upon. The new feature of the proposed method is the consideration of voltage security issue in the normal and emergency states since the voltage stability margin is explicitly treated in the formulation. The explicit inclusion of voltage security margin enables the TO to easily realize the critical VAR providers that should be contracted to maintain its required security level. This implies that the VAR providers in this market will be fairly remunerated based on their contributions in the system security that measures the relative worth of each VAR provider. The proposed method has been applied to the IEEE 57 bus-system to demonstrate its usefulness