期刊名称：Lecture Notes in Engineering and Computer Science
印刷版ISSN：2078-0958
电子版ISSN：2078-0966
出版年度：2019
卷号：2241
页码：167-173
出版社：Newswood and International Association of Engineers
摘要：Overcurrent relays (OCRs) are one of the most
common protective devices implemented in power systems to
protect electrical components from faults. In order to obtain
much improved protection by these protective devices, a
precise coordination of these systems must be applied. One of
the problems in power systems, which is very common, is when
a fault occurs in a plant, and two, three or even several OCRs
operate instead of the designated relay at that particular fault
location. In this work, the technical data of 2X15MVA,
33/11KV Maitama injection substation was collected and used
for modelling relay coordination for the station. After the
coordination, the result shows that 33KV feeder will trip on
over current and earth faults if the secondary current of the
CT exceeds 1.32A and 0.264A within 0.021s and 0.00167
respectively. For the 11KV outgoing feeder, it will trip on over
current and earth faults if the secondary current of the CT
exceeds 0.88A and 264mA within 12.5ms and 1.7ms
respectively. From these results, it is noted that earth faults
trip faster than overcurrent fault; this is because of the
harmful nature of earth. If it’s not isolated fast in an
interconnected system, it will cause a lot of damage to both
power system components and personals.
