Transaction Problems And Optimization Models Of Electricity Industry In Open Power Market

Electricity industry reform aims to break monopoly and build competitive electricity market. Marketlized transaction mechanism makes generators, power-supplying companies, power grid companies and customers independent participants to take part in transaction. In electricity market, many kinds of trade mode are used to optimize the electricity resource based on the price signal. Electricity transaction optimization is researched in this dissertation as follows:Firstly the formation of price chain and pricing mechanism in different electricity industry modes are demonstrated. The electricity pricing mechanism has been transformed from single government pricing mechanism into multiplied pricing mechanism including government regulation, market competition and contract pricing mechanisms. Aiming the unreasonable electricity price chain, some solutions are presented to perfect electricity pricing mechanism and effectively reduce the level of electricity price in China.In chapter three, main electricity transaction modes and settlement mechanism are introduced. The generation cost structure on thermal unit and the factors affecting generation cost are analyzed. Principal-subordinate two level optimization model is presented based on single-buyer market. To coordinate different electricity transaction, a coordinating optimization framework is given. Some models are formulated to optimize the transaction in long-term, medium-term, short-term and super short-term electricity market.From the economics analysis, the foundation of non-incremental bidding is discussed. Based on above, in chapter four the form of non-incremental bidding is designed. To study the transaction optimization mathematics model is built in PAB mode. Involving discrete and continuous variables, the goal function of the model is a discontinuous and differential function. A heuristic algorithm is presented to solve the model. This algorithm has advantages of easily calculation and fast constringency speed.The principal and problems of hydropower market transaction are discussed in chapter five. To solve the electricity transaction optimization combined with hydropower unit, a discrete-mixed model of electricity transaction is described. The optimizing principal is to minimize the total cost of purchasing the thermal-power in precondition of hydropower and thermal-power meeting the load demand, and the hydropower unit need not bid and the cost of hydropower in the model is zero, so the hydropower can be utilized with priority. To solve the non-linear discrete-mixed programming problem, load and unit are classified based on load types. A decomposing-coordinating algorithm is presented to simplify the model, avoiding the curse of dimensionality, increasing the calculation efficiency.Aiming to how the power grid company purchase the reserve capacity to maximize its benefit, chapter six analyzes the reserve bidding of generation unit with accountant cost theory, the reserve capacity optimization model in generation side is demonstrated. And according to the interruptible load and interruptible price submitted by customers, the reserve capacity discrete optimization model taking the interruptible load as reserve capacity is built. Based on the above models, reserve market joint optimization model considering generation reserve and interruptible load is presented. To use the interruptible load, power company can only stop the power supply, so the optimization model includes discrete variable. A heuristic algorithm based on the steepest descent method is used to solve the above optimization model. Compared with the reserve transaction mode only having generation reserve or interruptible load, the joint reserve transaction is more beneficial for the power grid company.Combined with the experience of electricity industry reform over the world, chapter seven analyzes the problems in larger users directly trading with power plant, and brings forward the appropriate transaction mode direct trade through public power grid. For the designing power price, it formulate the step-wise linear function between electricity consumption and power price, and share the capacity cost and reserve cost of unit on the power block of large-user to recover the generation cost. A double-goal optimization model of designing power price is discussed to consider the benefits of power plant and large-user together.