含分布式电源的中低压配电网继电保护研究

发布时间：2018-08-01 11:20

【摘要】：分布式电源因其在资源利用和环境保护方面的优势在世界范围内得以快速发展。作为大电网集中供电的有益补充，成为世界各国电力系统发展的必然趋势。各类分布式电源的接入，改变了配电网的故障特征，给配电网继电保护带来多种影响。多端供电改变了配电网故障电流的分布，使部分电流保护灵敏度降低或失去选择性。光伏、风力等分布式电源出力的波动性、间歇性，，高渗透率下分布式电源的启停，使配电网故障电流大小、方向存在不确定性。经逆变器并网的分布式电源运行及故障特性与传统发电机有很大不同。这些都使配电网原有继电保护适应性降低，甚至不能正确地识别、隔离故障。本文从各类分布式电源的原理及接入电网方式入手，深入研究其故障特性。通过研究逆变器型分布式电源的控制与特性，得出其在故障暂态下的等效模型，分析其在配电网故障时的输出特性。详细分析了分布式电源的数量、容量、接入位置对原有电流保护的影响。结合中低压配电网运行及接线方式明确了不同类型的分布式电源并网变压器及接地方式的选取对接地电流保护的影响，指出合理的选择方式。分析了分布式电源对自动重合闸的影响并提出解决措施。在分析现有继电保护存在问题的基础上，结合实例提出单个DG经专线及T接线路并网的保护整定优化方案。进而提出适用于多个DG并网的记及DG控制特性的三段式自适应电流保护算法。最后结合某工业园区光伏组合并网实例，提出保护配置设计方案，并通过仿真分析了多DG并网对原有线路保护的影响，验证了自适应保护算法的可行性。
[Abstract]:Because of its advantages in resource utilization and environmental protection, distributed power generation has been developed rapidly in the world. As a beneficial supplement to centralized power supply in large power grids, it has become an inevitable trend in the development of power systems all over the world. The access of all kinds of distributed power sources changes the fault characteristics of the distribution network and brings many influences to the relay protection of the distribution network. Multi-terminal power supply changes the distribution of fault current in distribution network and makes the sensitivity of partial current protection decrease or lose its selectivity. The fluctuation, intermittent and high permeability of distributed power generation, such as photovoltaic, wind power, make the distribution network fault current size and direction uncertain. The operation and fault characteristics of distributed power supply connected by inverter are very different from those of traditional generators. All these make the original relay protection adaptability lower, and even can not correctly identify and isolate the fault. In this paper, the fault characteristics of all kinds of distributed power generation are studied, starting with the principle of distributed power generation and the way of connecting to the power network. By studying the control and characteristics of the inverter distributed power supply, the equivalent model of the inverter in the fault transient state is obtained, and the output characteristics of the inverter in the distribution network fault are analyzed. The influence of the quantity, capacity and access position of distributed power source on the original current protection is analyzed in detail. Combined with the operation and connection mode of medium and low voltage distribution network, the influence of different types of distributed power supply grid connected transformers and the selection of grounding mode on grounding current protection is clarified, and the reasonable selection mode is pointed out. The influence of distributed power supply on automatic reclosing is analyzed and the solutions are put forward. On the basis of analyzing the existing problems of relay protection and combining with an example, this paper puts forward an optimal scheme of protection setting for a single DG line connected by special line and T line. Furthermore, a three-stage adaptive current protection algorithm is proposed, which is suitable for multiple DG grid-connected and DG control. Finally, the protection configuration design scheme is put forward by combining photovoltaic grid with an industrial park, and the effect of multi-DG grid-connected network on the original line protection is analyzed by simulation, which verifies the feasibility of adaptive protection algorithm.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM77

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