Published by Dranetz – BMI Case Studies
In 2000, DHL Airways opened a new 24/7 customer service center to support its US customer base. To maximize uptime and ensure high reliability, a redundant UPS system was installed, protecting both the supply and the facility loads. Integral to the facility design was the Signature System power monitoring system from Dranetz-BMI installed on the input and output of these UPS systems. The Signature System provides real-time access to all power monitoring information using a standard web browser. This feature was quite important to the nationwide facility manager who travels frequently and required remote access to the facility’s infrastructure regardless of his physical location. He also needed a system that allowed multiple facility personnel from around the world to review system data, view trends to prevent future problems and remedy any inconsistencies.
Within a mere few months, the Signature System provided valuable information to ensure power reliability at this critical facility. Most important, the system verified the expected performance of the UPS system and detected no disturbances on the UPS output feeding the critical loads (Figure 1). However, monitoring the incoming power from the utility supply indicated more than 50 disturbances in the first three months of operation (Figure 2). These disturbances included sags and transients that could have impacted unprotected loads, seriously compromising power reliability. Armed with the data, the facility manager contacted the utility who was able to pinpoint the problem as a faulty relay. The problem was corrected, while the Signature System continues to provide proactive information to support the uptime needs of the facility.
Trend of the voltage at the UPS output indicating excellent voltage regulation characteristics and support of the critical loads during all of the utility supply systems disturbances.
Power quality data trends at the UPS input indicating interruptions, voltage sags and transients from the utility supply.