Uncertainty Planning Of Active Distribution Network Considering Scale Grid Connected Photovoltaic System

The shortage of traditional energy supply has stimulated the power market to develop in the direction of high efficiency, flexibility, intelligence and sustainable development. The development of renewable energy power generation technology solves the problem of the grid connected operation of distributed generation in the medium voltage distribution network. But there are still a problem of distribution network structure is weak and lack of absorptive capacity of renewable energy etc.. Active distribution network (ADN) manages the power flow by using the flexible network topology, so that the local distributed energy (DER) is actively controlled and managed. The purpose is to increase the capacity of distribution network for renewable energy, improve the utilization of distribution network assets, delay the investment of distribution network upgrade, and improve the quality of the user’s power and power supply reliability..Firstly, this paper introduces the concept of distributed PV trusted output, and proposes two calculation methods of distributed PV capacity, which provides basic data for active power distribution network. Then, the load characteristics are analyzed, and the unified planning model of "substation-grid-distributed PV" is established. The process is based on the previous research data, using genetic algorithm, taking overall planning cost minimum as the goal, including investment and operating costs of substation, network investment cost, the operation cost of the grid (i.e. network loss conversion cost), reliability risk cost and the cost savings because of equipment utilization rate raised etc., including the system constraints. The final optimization results include the whole distribution network planning area of the grid layout, the proposed substation capacity and distributed PV installation location. Finally, the distribution network planning, distribution network planning investment is gradually reduced with the increase of PV penetration rate, so that can find the current planning area of the best PV penetration rate.This paper verifies the feasibility of the calculation method of the distribution network planning and the planning of the photovoltaic power supply.The planning results of the photovoltaic power supply show that the photovoltaic access position is biased in favor of the distributed access, and the access of the photovoltaic power supply can reduce the network loss of the distribution network. In this paper, the planning algorithm is analyzed and verified by examples, the distribution of PV is optimal, and the structure of the network is optimized by the method of cost optimization; finally, this paper makes a comparative analysis of the construction and operation cost, the cost of the line expansion, the cost of the transmission line and the cost of net loss in the substation; it can be seen that with the continuous improvement of the PV penetration rate, the total investment cost of distribution network construction has been decreased, and the feasibility of the planning method has been verified.