风力发电机组接入配电网对继电保护的影响及对策

发布时间：2018-05-16 12:18

本文选题：分布式电源 + 配电网　；参考：《西安科技大学》2017年硕士论文

【摘要】：分布式电源作为一种新型的发电技术,因为其具有灵活性、环保性、经济性等优点近几年来被不断开发应用,取得了较好的成绩。分布式电源接入配电网后,配电网的结构发生变化,原来单向潮流的简单配电网变成了双向潮流的复杂配电网。导致配电网上原保护装置受到影响,给配电网的正常运行带来考验。分布式电源并网后,配电网传统的电流保护不能满足继电保护的要求,因此需要对原保护进行改进,同时寻找其他更有效的保护方法。在分析分布式电源技术基础上,建立一个含有风力发电机组的10kV配电网仿真模型,主要针对风电机组并入配电网后,从风机容量、接入位置和故障位置等方面研究对配电网保护的影响,得到结论:位于风机下游的保护,风机会给故障点提供较大的短路电流,造成下游保护范围扩大从而失去选择性;位于风机上游的保护,风机会给故障点提供反向的短路电流,造成上游保护失去方向性。通过MATLAB仿真证实了分析结果。考虑到传统保护无法适应分布式电源接入配电网引起的变化,对配电网的安全运行造成巨大影响,研究应用自适应电流保护技术。提出一个新的求解等效阻抗方法,即根据故障发生前后保护装置测得的数据,利用对称分量法提取正序分量进行求解,目的在于重新整定电流保护定值。研究得出自适应电流保护性能优于传统保护,能够满足在风电机组接入配电网的情况下,在保护范围外可靠不动作,保护范围内可靠动作。通过MATLAB仿真证实了算法的可行性。
[Abstract]:As a new generation technology, distributed power generation (DG) has been continuously developed and applied in recent years because of its advantages of flexibility, environmental protection and economy. After the distributed generation is connected to the distribution network, the structure of the distribution network changes, and the simple distribution network of one-way power flow becomes the complex distribution network of two-way power flow. As a result, the original protection device on the distribution network is affected, which brings the test to the normal operation of the distribution network. Since the traditional current protection of distribution network can not meet the requirements of relay protection, it is necessary to improve the original protection and find other more effective protection methods. Based on the analysis of distributed power generation technology, a simulation model of 10kV distribution network with wind turbine is established. The influence of access location and fault location on the protection of distribution network is studied. The conclusions are as follows: the protection located in the lower reaches of the fan provides a large short circuit current to the fault point, which results in the extension of the downstream protection range and the loss of selectivity; In the upstream protection of the fan, the wind provides reverse short circuit current to the fault point, which causes the upstream protection to lose its directionality. The analysis results are verified by MATLAB simulation. Considering that the traditional protection can not adapt to the changes caused by the distributed power supply access to the distribution network and has a great impact on the safe operation of the distribution network, adaptive current protection technology is studied and applied. A new method to solve the equivalent impedance is proposed. According to the data measured by the protective device before and after the fault, the positive sequence component is extracted by the symmetric component method, the purpose of which is to reset the value of the current protection. It is concluded that the adaptive current protection is superior to the traditional protection and can meet the requirements of reliable operation outside the protection range and within the protection range when the wind turbine is connected to the distribution network. The feasibility of the algorithm is verified by MATLAB simulation.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM77

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