Study On The Protection Scheme For Distributed Network Considering Distributed Generation

Users require more security, reliability and quality to electricity supply today, however, large-scale power grid due to their own shortcomings of a single power supply can not meet these requirements, distributed generation is a better solution. Distributed generation is also an effective means to improve energy efficiency and solve the energy shortage problem. The capacity of distributed generation is between tens of kW and tens of MW, located in the vicinity of load, and the distributed generations are clean, environmental, economic, efficient and reliable generation mode. In recent years, the distributed power generation technology has large-scale development. It makes distributed generation become the main research directions of the future power generation technology.Since the current protection system of distribution network is designed according to the single power supply and radiation structure, these small capacity generations paralleled in change the distribution network from single power supply and radiation structure into double-power or multi-power network, the original protection of distribution system need to make appropriate adjustments and changes. This article mainly researches on the followings: 1) Research the background and significance of distributed generation. Distributed generation will be within a certain region or certain enterprises owned by various units with the distributed generation resources, it supply power to all units linked together through distribution network and large-scale backbone network runs in parallel. Distributed generation becomes an important means to effectively improve the energy efficiency and solves the energy shortage.2) Research the status of the distribution network in Shanghai, select the typical network as a analysis model to study the factors and measures of protection. In this article, depth study is carried out on distance protection applications in power distribution network. According to the characteristics of micro-grid, the current suggestion is to use over-current protection device or distance protection device.3) Establish a simplified model of the combination of typical distribution network and the distributed generation, The distributed generation grid in different locations, it can make distribution network short circuit anywhere on the transmission line, and can analyze the impact of short-circuit measurements in all kinds of typical situations.4) Shanghai Municipal Electric Power Company construct the energy conversion integrated display park near the 220kV Caoxi substation, this article give some preliminary feasibility analysis, study the energy storage system and network trend after the impact of power, According to that, the paper presents the recommendations on the protection of the distribution network with distributed power.Finally, for all the protection schemes proposed in this paper, QCTL test models with distribution parameter are established. Simulation results verify the feasibility and validity of all the protection schemes.