Impact of APC Schneider UPS power supply on system availability

The purpose of this paper is to introduce the impact of power interruption on the availability and uptime of AC power supply system, and to provide quantitative data about the uptime in the actual environment, including the impact of UPS power supply on the uptime. These data also relate to the impact of outage frequency and duration, and device restart behavior

The purpose of this paper is to introduce the impact of power interruption on the availability and uptime of AC power supply system, and to provide quantitative data about the uptime in the actual environment, including the impact of UPS power supply on the uptime. These data also include the influence of outage frequency and duration, equipment restart behavior, and UPS reliability related factors. In addition, this white paper will also list the advantages of extending UPS operation time to improve system reliability.

At present, the requirement of IT system uptime is increasing day by day, and the reliability target is usually set at 99.999% (five nines). However, many factors will become the resistance of the system to achieve this high standard level, and the reliability of AC power supply is one of the obstacles that can not be ignored. However, the relationship between AC power supply reliability and normal operation time is not particularly obvious, and the reliability of AC power supply in different locations is usually very different, which further complicates the situation.

Standardized data on AC reliability are extremely limited. However, two extremely important AC reliability surveys were conducted in the United States, one by att Bell Laboratories and the other by IBM. In addition, since Schneider Electric has installed more than ten million UPS systems, and many of them can record power problems, we have accumulated some experience in this field.

AC power supply problems can be roughly divided into three categories, which are: 1. Power failure or low voltage that will cause temporary stop of load equipment; 2. Transient voltage that will cause temporary suspension or failure of load equipment; 3. Transient voltage that will damage load equipment. This paper mainly analyzes the first type of AC power supply problem, that is, the impact caused by power failure or low voltage.

Therefore, our assumption is that 1) the device is properly protected by a surge suppressor or UPS to cope with transient voltages, or 2) actual downtime due to AC power supply problems will be longer than described in this paper.