Study On Power Plant's Reactive Cost In Power Market

The reactive power is of great significance. It can reduce loss, improve voltage wave, increase power quality and maintenance system stabilization. As the generation and net disjoined, remunerating the reactive cost relates the benefits of the generation and transmission. As the research on it has not received significant attention until recently, the theory on it is still not well defined. Many researches about reactive power as caculating the purchase and price etc. are based on the reactive cost function of generator, but the cost function nowadays is just an estimated model. This paper analyzes the reactive cost function of generator . This paper analyzes the generator's cost from two aspects: generator self and the system contribution. First from system aspect, this paper uses voltage sensitivity, PV curves method, equivalent reactive compensation method, back-up generation method to evaluate the reactive value of the generators in seven buses system and IEEE 14 buses system. The VS and PV methods can evaluate the source's ability of tracking the load's variation. The ERC and Back-up methods can evaluate the availability of replacing other generators.The value determines the cost.Second, this paper analyzes the relation of reactive support service with voltage, power limit curve, transaction amounts. According to the power limit curve, this paper analyzes the source of the reactive cost to get an interzone cost function. Using marginal cost theory, it concludes that the reactive spot price is the derivative of the cost function in generator buses. Using a generator's parameter, this paper gets the reactive cost function. In order to assure the rationality of the cost function, it calculates the derivative of the cost function and the real-time price with the cost function.The last, this paper discusses the application of the cost function. According to the interzone character of cost function, this paper advises a stock method. Thegenerators submit their offers in every zone to the ISO. The ISO settles the market according to the objective of the minimum purchase cost and declares the uniform market prices of each component separately. This paper uses MATLAB symbolic tool box and primal-dual interior point method to program optimal power flow in order to get a research tool .The tool is applied to caculate real-time price and reactive power purchase problem.