Protection Adaptability Evaluation Method for Distributed Generation Access to Distribution Network

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.