Analysis of D-STATCOM Impact on Protection of Distribution Network

-Impact of the compensation devices on relay protection is an important issue affecting secure operation of transmission systems. Currently, solutions for this problem are widely demonstrated in literature and in practice. At the same time, application of these devices in distribution systems is increasing due to their ability to improve power quality. Nevertheless, less attention has been paid to questions related to the influence of the devices on the standard protective schemes in medium voltage networks. In this paper, investigation of this issue is performed for the time overcurrent relays and impedancebased protection utilized due to presence of distributed generation in the grid. The research method consists in analysis of transient characteristics of measured electrical quantities during fault situations. The results reveal negative impact of the DSTATCOM on the typical overcurrent protection, and impedance relays are proposed as a solution; furthermore, positive and adverse effects for them are also introduced. The findings help to disclose possible problems at planning stage and to establish directions for further studies.