Value Assessment Research Of Battery Energy Storage In Smart Grid

In the six links"exploitation-generation-transmission-distribution- consumption-storage"of power system operation process, energy storage technology have been considered as an important part. After the introduction of energy storage into the power system, it can achieve demand-side management effectively, reduce the peak-valley difference between day and night, level the load, on the one hand, the utilization factor of electrical equipment improved effectively and the cost of electricity reduced, on the other hand, the renewable energy utilization promoted. Energy storage can be used as the means to improve the system stability, regulate the frequency and compensate the load fluctuation. The application of energy storage technology will bring out the significant change in the design, planning, dispatch and control of traditional power system, as a storage technology with mature technology and excellent regulation performance, battery energy storage has been captured people's wide attention.The purpose of assessing the value of battery energy storage is to establish the assessment model contain various value aspects, to determine the best application size and analyze its economic by optimal operation. When it is used in different occasions of power system, aim at different investors, these major value aspects are different, so Respective assessment model is needed.Related research in our country is still poor, and the energy storage value aspects accounted into the foreign research literature is not comprehensive enough, e. g grid loss cost reduction, power outage cost decrease and so on. Aim at the three main occasions that the battery energy storage applied: the grid-side, the user-side and wind farm, this dissertation makes a study about its values more comprehensively. The value assessment models mostly take the net income maximizing as the objective function, establish the constraints by combining with the charge/discharge characteristics of the battery, and use particle swarm optimization(PSO) to solve the examples respectively. when the grid operator build the battery energy storage system(BESS) in a substation, it can bring such values: deferring facility investment, saving the grid loss cost, energy price arbitrage, as spinning reserve capacity for distributed generators, decreasing the reliability cost of the grid; When the BESS is applied to the user-side, the main task is leveling the load and using as a uninterruptible power supply(LL+UPS), so the main values contain: decreasing the distribution capacity that the user needed, saving the electricity charge by energy price arbitrage, reducing the cost of distribution transformer loss and power outage cost; and when it is used in the wind farm, the main values contain: reducing the integration channel capacity needed, cutting down the reserve capacity that the wind farm needed, increasing the revenue of selling electricity by time-shifted energy from storage(transfer part of the valley electricity to the peak electricity) under peak-valley electricity price, this section establishes the net income objective model, and also considers the regulation performance of the BESS to the wind farm, takes the wind farm output power fluctuation index as one of the objective functions, then makes the multi-objective optimization model single by membership function method.Based on the research of our predecessors, this dissertation takes a more comprehensive assessment to the value of the BESS, provides some reference for the application and popularization of this technology.