Protection system in power distribution system in data centre in the UK

Abstract

A well-designed protection system in a power distribution system ensures the continuity of power delivery. Even though this can't prevent a fault, which can lead to a catastrophic situation when the protection will not operate correctly, therefore, protection devices must be correctly selected and installed to avoid these consequences. The power system in a data centre is constructed of prominent features like generators, power supply cables, high and low-voltage transformers, and UPSs with a battery backup system and protection system. Researchers have looked at the problems in terms of faults inside a UPS system which is about protecting the UPS unit itself rather than the power distribution system within the Data Centre. If the fault occurs inside the UPS unit, then internal protection will shut down the faulty unit, and a redundant UPS N+1 will turn on. Operation of the UPS system with “in use” redundancy of the UPS is a critical moment for power delivery security. If the redundant UPS is lost, power backup is lost, so engineers must do repairs quickly. I concentrated on the protection system within the power distribution network in a data centre, not internally to a UPS. The thesis presents the coordination of a protection system with the help of using the ETAP 21 software. The designed power system level is 11kV/400V AC with 50Hz frequency and a capacity of up to 8MW connected to two different DNO grid power networks. The power distribution system includes a backup system to ensure continuity of supply when both DNOs supplies have outages. The simulated protection coordination into randomly selected equipment, line or busbar under the fault condition will show the sequence of the operation. The primary protection has been designed to operate first as it is closer to the fault. However, when it fails to operate, then backup devices in the sequence must operate to isolate the faulty equipment. Protection elements like fuses and circuit breakers are not designed to prevent the fault. The protection, however, senses and operates fast to limit the fault current severity that causes damage to the equipment and increases the system's safety. An integrated part of achieving those is selecting appropriately rated protection devices and switchgear and performing a protection study. Regular maintenance is essential to correctly working the power system and the protection.