A Study Of Reactive Power Pricing In Initial Stages Of Electricity Market

In electricity market, electric power transactions cannot carry out without ancillary services. Ancillary services play key roles in terms of maintaining the security and the reliability of power system and advancing the quality of electric energy and so on. Reactive power service is one of ancillary services in power system. The research on plan, operation and control, evaluation and pricing of reactive power in power system is currently an active field in ancillary service studies. But as for reactive power pricing, there has not been the mature theory. For the moment, most of pricing methods for reactive power are reactive power real-time pricing methods based on maginal cost theory, which pay close attention to market efficiency. But reactive power real-time pricing methods go against recovering the investment cost of reactive power and are hard to inspire the investment to reactive power in side of capital market due to the characteristic that the investment cost of reactive power is a main part of its cost. At the same time, considering the role of reactive power as ancillary service, the security value of reactive power is even bigger than its economy value in power system. So, how to evaluate the security value of reactive power is one of issues that need to be faced and solved for reactive power pricing theory. With the practice of the initial stages of electricity market in our country, reactive power pricing must take the steadiness of price policies into account and pay more attention to the combination of competition and regulation. Based on the above, the research work for reactive power pricing is as follows:Firstly, an interior-point nonlinear programming algorithm is introduced. This method is principlely simple, converges quickly and can save calculationtime. Based on the mathematical models that are further deduced for several key issues of the algorithm under right-angle coordinates and polar coordinates, the paper analyzes the efficiency of solving a multi-objectives optimal power flow by the proposed method and deduces some correlative conclusions. The method lays the foundation of the imitation experiment of reactive power multi-objectives optimal power flow.Secondly, expense-compensating reactive power pricing methods for initial stages of electricity market are put forward. Based on setting up the procurement method of reactive power compensating expenses, three expense-compensating reactive power price models are constructed, and their characters and application scope are analyzed. These methods provide suitable reactive power compensation mechanisms for initial stages of electricity market.Thirdly, new two-part reactive power pricing methods are developed, which include the two-part pricing method that active and reactive power is separately optimized and the two-part pricing method that active and reactive power is unitedly optimized. The former puts forward a new way to decompose reactive power cost and is suitable for application in the market in which active and reactive power are independently traded. The latter gets the optimum economy of system operation and is suitable for application in the market in which active and reactive power are simultaneously traded. Two-part reactive power pricing method, in which the reactive power energy cost takes part in competition, puts forward a new scheme to decompose capacity price while balancing. It does well to recover reactive power investment cost.Fourthly, equivalent-value reactive power pricing method is developed. The method emphasizes that reactive power price revenue should 'equal' to its contribution in economy and security. The presented reactive power optimal method takes its contribution to the economy and the voltage quality of power grid into account. The equivalent-value reactive power pricing method proposes to participate competition as energy bid and to automatically complement capacity revenue whilesettlement. The equivalent-value reactive power price pays more attention to the combination of regulation and market and emphasizes the full compensation of reactive power investment cost to remedy the deficiency of the two-part reactive power price. Therefore, the price model has the effect on inspiring the reactive power investment. The equivalent-value reactive power price considering economy factor further emphasizes the local contribution of reactive power, and converts it as economy factor to reckon in the settlement price of reactive power. The method has the effect of which power grid actively evaluates the zonal value of reactive power.Finally, the equivalent-value reactive power pricing method under multi-operational conditions is further presented. The method using the recursive optimization strategy of reactive power guarantees the economy and the security and the power supply quality of power system under power grid continious operations. The equivalent-value reactive power price still has good adaptability under multi-operational conditions. How to ensure the optimum performance of power system for the proposed reactive power optimization method in different system operational conditions is analysed in case study.