Optimal Power Planning Of Micro Grid Containing Wind PV Battery Power Sources Based On Equivalent Credible Capacity Theory

Sustainable development demand have caused worldwide study on the use of renewable energy, with its price becoming cheaper, more and more renewable energy have been accepted to a distributed power system. With larger number of new energy units connected to the grid through power electronic equipment, which directly affect the power quality of distributed power system, cause voltage fluctuations. But if the distributed generation connect to grid in the form of micro-grid, which will both support bulk power system and the local power grid, it alsocan avoid a direct impact on the surrounding intermittent power user power quality and help reduce transmission losses of distributed power.Since the output of new energy units fluctuates because the uncertainty of natural resources, the traditional methods are difficult to evaluate the effectiveness of its power generation capacity, So we must find an effective way to evaluate the new energy power planning.Therefore,in this paper, the credible capacity and complementary benefit of Coordination System of Wind Power, Solar Energy and Energy Storage was studied, and new methods on optimal configuration of distributed generation system containing Wind PV Battery Power Sources Based on Equivalent Credible Capacity Theory was proposed.Finally, a set of index system on evaluate dynamic spatial and temporal characteristics of micro-grid power supply was established.By considering the operating characteristics of the energy storage device, the calculation method of credible capacity of the hybrid generating system consisting of wind power, solar photovoltaic power and energy storage is presented, which based on sequential Monte Carlo simulation, and Probabilistic production simulation that contain wind power, solar photovoltaic power and energy storage. On the basis of operating strategies of energy storage above, the influence of how the installed capacity ratio of energy storage, wind power, solar photovoltaic power generation affect the credible capacity are evaluated. The proposed models were applied to IEEE RTS79and the simulation calculation was performed by programming in Matlab.In this paper, the operating characteristics of micro-grid was studied,and then different investment decisions for island and connecting mode of micro-grid was presented, with the establishment of different power optimization objective functions. On the basis of analysis on timing characteristics of different types of distributed micro-grid power generation, the stochastic simulation method to study the operation of micro-grid was proposed. Based on the investment decisions objectives and production simulation methods proposed above, a micro-grid power optimization model based on time series forecasting data was established.In the capacity optimization of coordination power generation system containing wind farm, photovoltaic (PV) generation and battery hybrid system, the uncertainty factors to be considered include not only the random outage of conventional generation units, but also unit output fluctuation due to random variation of wind speed and illumination intensity. Based on equivalent credible capacity theory an optimal configuration method of wind PV battery hybrid generation system, in which the impacts due to random fluctuation of natural resources and random outage of conventional generation units are synthetically taken into account, is proposed and according to the demand on satisfying electric power balance the needed overall capacity of wind/PV/battery hybrid generation system and the capacity of conventional generation units are determined; then through Monte Carlo simulation the wind/PV/battery hybrid unit combinations needed by equivalent credible capacity are calculated; and then according to the optimal configuration model of wind/PV/battery capacity, the wind PV battery capacity configuration, which makes the total investment cost in full lifecycle minimized, is selected from above-mentioned combination sets. The validity of the proposed method is verified by results of calculation example of an actual island power system, which the wind power generation and PV generation are added in Micro-grid power supply planning project is uncertain on the spatial and temporal characteristics, which will impact the evaluation and optimal decisions. To calculate this influence, a set of index system on evaluate dynamic spatial and temporal characteristics of micro-grid power supply was established, including economic indicators, reliability indicators, efficiency indicators and environmental indicators. First change parameters was added in economic indicators, stochastic process model was studied to describe the dynamic spatial and temporal characteristics of micro-grid power planning projects, including future investment unit costs and fuel prices fluctuationduring the characteristic time, and then energy efficiency indicators, such as complementarymetrics of Coordination System of different intermittent power generation was proposed,and price risk ratio indicator was used to evaluate the possible risk of financial loss. Finally, the paper analyzes the relationship between the different levels of each metrics, and introducingthe Analytic Hierarchy Process(AHP) tounify all metrics, taking into account the dynamics of the spatial and temporal characteristics of the different micro-grid independent power planning to make a comprehensive evaluation. Simulation of a micro-grid island show that the method can supply different spatial and temporal characteristics of the planning scheme we preferred, and even it can provide a reference for energy policy to promote the development of low-carbon electricity.Finally, work in this paper was been summarized, and the development trend of this issue was discussed.