分布式电源接入配电网的保护适应性评估方法

Protection Adaptability Evaluation Method for Distributed Generation Access to Distribution Network

  • 摘要: 分布式电源(Distributed generator,DG)接入配电网后在发挥其优势的同时对传统基于单端电流信息的保护原理带来了挑战,而量化DG接入的影响可以通过调整适宜的DG容量提升保护性能,同时为DG接入后保护方案的完善提供参考。因此,为系统分析DG并网对保护的影响,量化评估保护原理的适应性,提出一种考虑DG接入的配电网保护适应性量化评估方法。首先,提出了反映继电保护“四性”的量化指标体系;其次,采用层次分析法(Analytic hierarchy process,AHP)和客观赋权法(Criteria importance through intercriteria correlation,CRITIC)相结合的方法对各指标进行权重赋值,结合分值量化得到了保护原理的适应性边界;最后,通过典型配电网算例进行分析计算,验证了评估方法的有效性。算例结果表明,所提方法能够量化评估保护的适应性,为DG接入后配电网保护的薄弱环节辨识和DG适宜容量设计提供理论依据。

     

    Abstract: After the distributed generator(DG) is connected to the distribution network, the traditional protection principle is no longer suitable for the existing fault characteristics. In order to systematically analyze the impact of DG grid integration on protection and quantitatively assess the adaptability of the protection principle, a quantitative assessment method for the adaptability of distribution network protection considering DG access is proposed. Based on the perspective of protection action, considering the maximum short-circuit current output by DG, a protection evaluation index system with DG is established. Combined with the requirements of relay protection, the calculation method of evaluation index is given by referring to the characteristics of protection and expert experience. An AHP-CRITIC combination weighting method based on the principle of minimum information recognition is proposed, and the adaptive boundary of distribution network protection is quantified. Finally, through a typical distribution network example, it is verified that the proposed method can obtain the weak link of protection processing fault after DG access and the appropriate capacity of DG to improve protection performance. The example results show that the proposed method can quantitatively assess the adaptability of protection and provide a theoretical basis for the identification of weak links in distribution network protection and the design of suitable capacity of DG after DG access.

     

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