太阳能是一种洁净可再生能源，利用光伏发电（Photovoltaic power generation），能够保护环境节约资源。分布式光伏发电系统（Distributed Photovoltaic Power Generating System，简称 PV 系统）并网运行可以节约成本、减少能源消耗、使系统的运行更加可靠，实现了供电方式的多样性。PV接入配电网的并网运行，将会给PV系统本身以及电网的拓扑结构、运行方式都带来重大影响。PV系统接入配电网后，导致配电网从简单的单一电源辐射状的供电网络变为有多个电源提供电能的复杂网络，潮流的方向不再是单一的，短路电流的大小和方向将会发生巨大的改变。这不仅会导致原有配电网继电保护出现拒动、误动、灵敏度改变等一系列问题，还会产生光伏发电系统的孤岛问题。所以，研究PV系统接入配电网对继电保护的影响进而提出相应的保护方案是非常必要的，对提高供电可靠性和电网安全运行有十分重要的意义。 本文在分析现有配电网保护方案的基础上，结合实际电网结构详细分析了光伏发电系统连接到配电网后对配网继电保护的影响，进而分析了孤岛形成的原因以及带来的影响。在常规保护基础上进行改进，提出了含光伏发电系统配电网的保护新方案：自适应保护方案。将系统划分为两个区域详细探讨了自适应电流保护的整定方案以及动作特性、实现流程。最后利用PSCAD平台搭建仿真模型，通过仿真模型验证了自适应电流保护方案的可行性和优越性。 PV系统接入配电网后，改变了传统配电网单一电源辐射型的结构，接入配电网的PV的容量大小和接入位置的不同都会影响到短路电流的大小和方向，原有配电网保护可能产生误动、拒动等现象，采用自适应保护方案能够增大保护范围，满足保护的基本要求，使保护处于最佳的运行状态。

Solar energy is a clean and renewable energy,uses PV (Photovoltaic power generation) to protect the environment and conserve resources.Distributed Photovoltaic Power Generating SystemParallel operation can save costs, reduce energy consumption, make the system run more reliably and then achieve a diversity of power supply.It will give PV system itself and topological structure、 operation mode of the gridhas a significant impact. When PV system accessing distribution network, it results in the distribution network from a simple single power radiating supply network into a plurality of power supply electricity networks, direction of the trend is no longer a single, short-circuit current magnitude and direction will be a huge change.This will not only lead to the existing distribution network relay protection occurring tripping, malfunction, sensitivity changed and other issues, but also product isolated island of PV system.Therefore, by the study of PV systems accessed to Power Network Relay Protection and then proposing appropriate protection scheme is very necessary,which will have a very important significance to improve power supply reliability and safe operation of power. This paper analyzes the impact of PV systems connected to the distribution network for relay protection, and then analyzes the reasons for the formation of the island as well as the impact.We use PSCAD platform to build simulation models to verify the impact of PV systems accessing for protection.Finally, we propose the distribution grid protection program including PV systems,Protection scheme constitute by the PV side protection and system side protection of the distribution network.Where in the PV side protection of systems is mainly anti-islanding protection; On the basis of a conventional protection ,distribution network protection of system Side is improved, we propose adaptive protection scheme.finally we verify the feasibility and advantages of adaptive current protection scheme by the simulation software. Because the basic requirements of the PV system connected to the distribution network, changed the traditional distribution network with a single power source radiation type structure, access to distribution network of the PV capacity and access location will affect the magnitude and direction of the short-circuit current, the original distribution network protection may generate phenomenon of misoperation and refusing to move, using adaptive protection scheme can increase the scope of protection, meet the best running state of the protection.