Open AccessProtection coordination of directional overcurrent relays: new time current characteristic and objective function
Author(s) -
Yazdaninejadi Amin,
Naderi Mehdi S.,
Gharehpetian Gevork B.,
Talavat Vahid
Publication year - 2018
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2017.0574
Subject(s) - overcurrent , relay , flexibility (engineering) , reliability (semiconductor) , computer science , protective relay , particle swarm optimization , electric power system , mathematical optimization , function (biology) , power (physics) , reliability engineering , control theory (sociology) , engineering , current (fluid) , algorithm , electrical engineering , mathematics , physics , quantum mechanics , evolutionary biology , biology , statistics , control (management) , artificial intelligence
Clearing power grid faults swiftly and selectively offers higher security, reliability and sustainability. Accomplishing this aim by deploying directional overcurrent relays (DOCRs) is one of the major challenges in meshed and multisource distribution networks. To overcome this challenge, the current study elaborates a new coordination strategy which concentrates on minimising overall operation time of relays. In this strategy, an auxiliary variable is added to classical operation time model of each DOCR. All the auxiliary variables are considered as coordination constraints which help to yield new and well‐defined time current characteristics (TCCs). In other words, more flexibility is attained in adjusting relay's characteristic which helps to alleviate clearing time of faults. The obtained TCCs can be easily performed by numerical relays. In addition, a new objective function is defined to steer the relay settings towards optimal solutions conveniently. It was shown that the proposed approach not only reduces the operation time of relays, but also prevents miscoordinations. This approach demonstrates a non‐linear programming model tackled by particle swarm optimisation algorithm. The effectiveness of the proposed approach is verified via 8‐bus and IEEE 14‐bus test systems and results are discussed in depth.