Assessing the reactive power support requirements for generators in a competitive electricity market

Under the new competitive electricity market structure, the active power provided by the generator has become a commodity, entering the transmission grid with few restrictions. It is known that the transmission of active power needs the support of reactive power and the amount of support is a function of the active power transmitted. Our studies found that each generator does need a certain amount of reactive power to support the transmission of its own active power. The amount needed is a function of the generator location, the amount of active power transmitted and others. Any reactive power beyond this amount is purely used as reactive power support and should be remunerated. The main objective of this paper is to present an investigation on the problem of assessing the reactive power support of the generator. In this paper, we propose the concept of minimum VAr requirement (Q_min) for generators. A practical approach to determine the Q_min has also been developed and tested in a 5-bus system and a medium-sized system. Promising test results verify the validity of the proposed method.