active power

Active Power's CleanSource 750HD flywheel UPS reduces risk of system failure by 21% versus a double-conversion UPS, according to a reliability assessment.

Commissioned by Active Power, the study by MTechnology examined the reliability of CleanSource 750HD versus a double-conversion UPS with batteries and quantifies the likelihood of failure during three distinct scenarios: a long utility outage lasting more than 10 seconds; a short utility outage lasting less than 10 seconds; and a demand failure.

For this study, a demand failure is a condition where the UPS fails when called upon to support a load during a utility outage.

The report, ‘Mitigating Risk of UPS System Failure: Reliability Assessment of CleanSource HD Integrated Flywheel UPS versus Double-Conversion UPS with Batteries’, also evaluates the reliability of CleanSource 750HD with a secondary energy source which couples a flywheel with battery energy storage versus a legacy UPS.

Key findings from the independent study include CleanSource 750HD reduced the risk of failure by more than 21% during long outages versus the modeled double-conversion UPS with batteries, 6.73% versus 8.58%, respectively.

For short outages, CleanSource 750HD had an 80% lower probability of failure versus a double-conversion UPS with batteries, 0.50% versus 2.05%, respectively.

The likelihood CleanSource 750HD would not support the load when called upon (demand failure) was dramatically lower compared to a double-conversion UPS with batteries, 0.000067% versus 2.05%, respectively.

The addition of the battery option to CleanSource 750HD further improved reliability over legacy UPS. During long outages, CleanSource 750HD with ‘Extended Runtime’ reduced the risk of failure by more than 23% versus a double-conversion UPS with batteries (6.60% versus 8.58%, respectively).

During short outages, the system reduced the risk of failure by 85% (0.36% versus 2.46%, respectively). The improved reliability is due to the presence of two distinct energy sources (flywheel and batteries).

The most likely failure mode of a double-conversion UPS with batteries is due to undetected battery failures. Non-detectable and detectable battery failures account for more than 83% of all double-conversion UPS failures.

"The UPS should improve reliability in an electrical design, not introduce additional risk," said Todd Kiehn, senior director, Product Management, of Active Power. "We believe this study presents clear evidence as to how operators can enhance reliability and mitigate risk of downtime to their mission critical operation with CleanSource 750HD."