Best Practices: Load Banks for Generator Testing

Load Banks for Generator Testing

If backup generators fail to start or run during a power outage, your data center could face dire consequences. Standby generators support UPS systems, power distribution unit (PDU), remote power panel (RPP), bus track, switching gear, servers rack mounted, and cooling systems; lighting, fire alarm systems, elevators, and communications systems. Best practices recommend deploying load banks for generator testing to ensure your generators will perform when needed. In addition to load testing, reliable generator performance depends on quality equipment, trained operating personnel, regular inspections, preventative maintenance, and successful commissioning.

A rigorous commissioning and maintenance program can keep your data center’s generators functioning as required. According to a survey conducted by Building Operating Management magazine, 71% of data center facility managers say they test generators under load.

Generator Load Testing – When, Why, and How?

Data center operators typically perform load testing at the initial commissioning of the facility. Once a data center becomes operational, experts recommend load testing of the entire system at design load at least annually, if not monthly.

Why should you use load banks for generator testing? Backup power systems typically remain off and in a standby state. They wait for a command to start and then provide power for minutes, hours, or days during a power failure. Because backup generators lie idle for such extended periods of time, regularly verifying operational performance is paramount.

Load banks for generator testing should follow some general best practices:

  • Develop site-specific standard and emergency operating procedures before you begin the commissioning process for new data center projects. When properly planned, the commissioning phase provides the best opportunity for you to validate procedures, train your staff, and verify performance.
  • Prepare to commission backup power systems thoroughly after you install them. Commissioning includes operating all components and key features in various application modes, such as normal, bypass, and failover. It also requires testing under multiple loads ranging from very light to full design load.
  • Perform integrated system testing with actual loads connected from your HVAC, UPS, and other systems during commissioning of generators.
  • Consider renting portable load banks from an experienced load bank supplier. Most load banks include incremental switching that allows you to safely ramp-up generators without causing damage.
  • Follow the safety procedures recommended by your load bank supplier for testing and carefully establish connection procedures.

When conducting the load test, necessary procedures include:

  • Starting and running the generator until the water temperature stabilizes
  • Transferring all manual or automatic transfer switches to the emergency source
  • Step load the generator until you reach the desired load
  • After the test, remove the load bank load first
  • Return all transfer switches to normal
  • Follow the manufacturer’s guidelines for cooling down the generator
  • Observe generator performance during the load test. When the system is running, check all components to ensure normal operation.
    • Does the engine sound like it is operating normally? Is it vibrating?
    • Is voltage stable?
    • Do you see any excessive exhaust smoke?
    • Is the generator temperature operating within normal ranges?
    • Is fuel correctly transferring between the tank and generator?
    • How is the oil pressure?
    • Do you see any leaking oil, fuel, or coolant?
    • Have any alarms or alerts surfaced?
  • Operate the engine at or near full capacity for several hours. You want to experience a full heating and cool down cycle.
  • Log all aspects of the generator load test, including actual load, conditions, time of the test, critical building loads on or off, etc.

After using load banks for generator testing and completing a comprehensive test, you will have better confidence in your backup power systems. Testing validates your critical backup systems will perform should an unexpected power failure occur.

ComRent’s team of load bank experts helps ensure successful load testing of your data center generators. We provide a complimentary consultation to review your project and propose the right load bank solution to meet your requirements. Contact us today.

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