ROI From Improved Emergency Power Protection

Leveraging best practices in maintenance with state-of-the-art monitoring technologies and remote services will keep your UPS systems in compliance, reliable and available.

By Jane Alexander, Managing Editor

Because uninterruptible power supply (UPS) units and their batteries must function properly during unplanned outages, a compromised emergency power system can mean serious trouble. At this critical time, batteries supply power to digital control systems and emergency lube oil pumps, enabling automatic controls to do their job.

In applications like oil and gas, petrochemical and power generation, dead batteries that prolong power interruption can cause dangerous chemical-process instability, damage to equipment or, in some cases, the shutdown of a facility. Damaged equipment could take months and millions to repair, while lost power production could be more expensive and lead to fines and penalties. For example, in a recent case regarding the 2011 blackout in the southwest United States, a public power entity agreed to pay a $12 million civil penalty for its role in the outage.

According to Wally Vahlstrom, Director of Technical Services for Emerson Network Power’s Reliability Services group, a proper preventive maintenance program can help a plant avoid those types of costly incidents and, in turn, provide several added benefits.

Benefit: battery-testing compliance

Every emergency power system contains life-limited components that should be maintained according to recommendations from the Institute of Electrical and Electronics Engineers (IEEE), manufacturer specifications and as required by the North American Electric Reliability Corporation (NERC). Batteries are no exception. In the event of a power outage, a single bad cell in a battery string could compromise the entire backup system and leave a plant without protection.

While UPS battery manufacturers may market their batteries with a 10-year design life or life span, actual battery service life could be much shorter due to the external factors that cause degradation. Several effects that can shorten battery life include:

• Frequent discharge cycles
• High or improper room temperatures
• High or low charge voltage
• Excessive charge current
• Manufacturing defects
• Loose connections
• Strained battery terminals
• Poor and improper maintenance

In reality, batteries lose capacity in as little as three years. According to IEEE, the “useful life” of a UPS battery ends when it can no longer supply 80% of its rated capacity in ampere-hours. At this point, because the aging process accelerates, a battery should be replaced.

Benefit: increased battery life

Because of the many factors that can affect the useful life of a UPS battery, it is important that—as soon as it is placed into service—a battery be maintained with a program that identifies system anomalies and provides information that trends end-of-life. Through this type of maintenance program, plant owners and operators can get the most out of their investment in these critical assets.

Batteries that are beginning to fail cause an imbalance that adversely affects the life of other batteries in the string and should be removed from service. Moreover, when UPS battery replacement is needed, time is critical—especially in light of the financial impact an extended or unplanned outage can have on an organization. In a concerted effort to increase its system reliability, the public power entity cited in the above-referenced blackout expects to invest at least $20 million in battery storage facilities within its transmission operations area.

An increase in the number of annual preventive maintenance visits increases mean time between failure rates.

Benefit: maximized system reliability

To avoid UPS battery failure, the best practice is an approach that includes integrated battery monitoring and preventive maintenance (PM). In Emerson Network Power’s data analysis of more than 450 million operating hours for more than 24,000 strings of UPS batteries, the impact of regular preventive maintenance on reliability was clear. The analysis revealed that the mean time between failures (MTBF) for units that received two PM service visits a year is 23 times better than those that received no PM visits.

Furthermore, operations with battery monitoring systems installed at their sites had a reduced rate of outages due to bad batteries. While outages still occurred, the incidents were isolated to cases where customers were either not watching their system or did not know how to properly analyze the data provided by the monitor. This revealed the need for experts to correctly monitor the alarm data and properly maintain those systems.

Benefit: improved system availability

The ideal UPS battery maintenance program is one that uses monitoring in conjunction with remote services. Teams responsible for managing critical infrastructure are essentially able to augment their staff with a remote services solution that includes data acquisition, equipment trending, monitoring alert management, maintenance and remote diagnostics, as well as parts and service-personnel dispatch.

The latest technology, such as that used in Albér battery-monitoring products, can identify potential problems by tracking critical parameters like cell voltage, overall string voltage, current and temperature. Periodic tests of the battery’s internal resistance can also verify a battery’s operating integrity. For a UPS, technology can be embedded and allow, for example, continuous monitoring of multiple unique parameters. At defined intervals—or at the activation of a critical alarm—the monitoring device will communicate to a remote system engineer and provide alarm details, allowing immediate corrective action.

By combining monitoring with remote services, plant managers can define escalation plans that are executed upon any alarm condition. Your chosen service partner should have critical infrastructure experts available to support monitoring efforts 24/7 to improve overall system availability.  MT

Wally Vahlstrom is Director of Technical Services for the Electrical Reliability Services business of Emerson Network Power. For more information, visit emersonnetworkpower.com.