Abstract:

To solve the problems of high cooling energy consumption and difficulty in Power Usage Effectiveness (PUE) optimization in data centers,AC header cabinets in existing data centers are taken as the research subject.The impact of increasing ambient temperature to 32 ℃ on the operational reliability of miniature circuit breakers (MCBs) in the feeder branches of header cabinets is focused on,and the feasibility of reducing PUE by raising temperature is explored.ABB S200 series MCBs with a high market share are selected.Firstly,the rated current requirements of the AC header cabinets are calculated through formulas.Then,a thermal model of the header cabinet is established using Ansys software,and the internal temperature under 32 ℃ ambient temperature is simulated.The results show that the temperature at the installation position of the feeder MCBs is 40~45 ℃.Subsequently,combined with GB/T 10963.1—2020 Electrical accessories—Circuit breakers for overcurrent protection for household and similar installations—Part 1: Circuit-breakers for a.c. operation and product specifications,the possibility of misoperation of the feeder MCBs is analyzed theoretically.Finally,experimental verification is performed on 45 MCBs (divided into 5 groups) under the conditions of 40 ℃/45 ℃ ambient temperatures and 0.85I_n/1.05I_n loads.The results show that increasing the ambient temperature of the data center to 32 ℃ does not cause misoperation of the MCBs in the feeder branches of the header cabinet,nor does it affect the power supply reliability.

Key words: data center, AC header cabinet, ambient temperature, reliability