Protection of MV Closed-Loop Distribution Networks With Bi-Directional Overcurrent Relays and GOOSE Communications

Abstract

This paper proposes measures to improve the protection of MV distribution networks operating with feeders in a closed-loop arrangement. Bi-directional overcurrent relays (OCRs) are discussed, the selectivity of which is achieved through the timing coordination of their operation. The classic approach is formulated as a minimization of the operating times of all the OCRs. The proposed approach enhances the selectivity by considering the maximum operating time of substation OCRs and the unwanted trips of in-loop OCRs. Moreover, the sensitivity is also increased by introducing an objective function that minimizes the pickup-current settings of all the OCRs together with their operating times. Furthermore, to fulfill the demanding requirements for operating times, variable penalties are introduced. Thus, the optimization procedure is forced towards the region with viable solutions for the optimization problem. Two variants of self-adaptive differential evolution have been used that both show better convergence when compared to the classic differential evolution. Moreover, ten mutation strategies were tested, where ''rand/1/bin'' showed the best results. A comparison with other methods for timing coordination shows that the proposed optimization results in a comparable value for the OCRs' operating times. In order to further reduce the operating times, GOOSE communications between the OCRs are adopted. The proposed measures for improved protection operation are fully confirmed through dynamic simulations of the faults in the discussed 20-kV network. Moreover, the proposed protection design is already implemented and permanently operates in a 20-kV network with more than 5000 customers, whereas the field results show selective and reliable protection operation.

Smart Sensors for Smart Grid Reliability

“…The genetic algorithm was programmed in Matlab ® [56] on a 2.7 GHz Intel Core i5-5200 with 8 GB of RAM. The average computation time used for optimizing the tripping time of both sensors (S_1, S_2) was 0.7 s, which is lower than the 2 min detailed in [57].…”

Permanent Closed-Loop Operation as a Measure for Improving Power Supply Reliability in a Rural Medium Voltage Distribution Network

“…The results presented in this paper were obtained for the protection system realization without the exchange of GOOSE messages. More details about the protection system realization are provided in [11], emphasizing the exchange of GOOSE messages.…”

An Adaptive and Scalable Protection Coordination System of Overcurrent Relays in Distributed-Generator-Integrated Distribution Networks

“…In [23], a novel protection coordination algorithm is developed to improve the selectivity of the protection system through using a three-level communication network, directional overcurrent protection functions, and under/overvoltage-based protection functions, which are available in digital relays. On the other hand, references [24,25] have considered sequence-component-based protection functions, e.g., positive-, negative-, zero-sequence components, along with a GOOSE (Generic Object Oriented System Event) solution for detecting, classifying and isolating symmetrical and asymmetric faults in microgrids or DG-penetrated distribution networks. Generally, embedding several different protection functions into a digital relay could be a feasible solution to improve the adaptability and flexibility of a DN protection system, which has been applied for this study.…”

“…Directional OC (DOC) relays and coordination algorithms: In [17,24,[44][45][46][48][49][50], the optimal coordination of DOC relays in the distribution network has been performed. Reference [17] uses a simplex algorithm to solve the protection coordination of DOC relays as a linear programming problem.…”