Protection Scheme for Distribution Network Ground Fault Based on Comparison of Zero Sequence Magnitude

In view of the increasingly complex structure of the distribution network and the deterioration of the existing zero-sequence current protection due to the access of distributed power sources, this paper proposes a new protection scheme for single-phase grounding faults in the distribution network by using the widespread configuration of the first and second deep fusion switches in the distribution network, which makes it easy to measure the zero-sequence voltage and zero-sequence current directly, and the real-time data transmission brought by 5G communication technology. The following new protection scheme is proposed: with the help of 5G communication network, the zero-sequence voltage amplitude and line zero-sequence current amplitude of each bus node measured by the first and second depth fusion switches are transmitted to the intelligent protection center, which locates the faulty line and issues commands to isolate it from the fault. The scheme uses the magnitude information of the zero sequence electrical quantities after the fault and does not depend on strict data synchronization. As verified by PSCAD/EMTDC simulation, the scheme improves the reliability and resistance to transition resistance of traditional zero sequence current protection, and can selectively achieve fault isolation even in the case of communication abnormalities resulting in partial information loss, which has good engineering application value.