UPS Operation SOP

UPS Operation SOP

1. Purpose

To provide a standardized procedure for safe and reliable operation of UPS systems, ensuring uninterrupted power supply to critical loads.

2. Scope

Applicable to all online, line-interactive, and offline UPS systems in data centers, hospitals, industrial plants, or commercial buildings.

3. Responsibilities

  • Operators: Monitor UPS operation, follow procedures, and log readings.
  • Maintenance Team: Conduct preventive maintenance and troubleshooting.
  • Supervisors: Authorize switching between mains, UPS, and bypass modes.

4. Safety Precautions

  1. Only trained and authorized personnel should operate the UPS.
  2. Wear PPE (insulated gloves, safety shoes, eye protection).
  3. Do not bypass UPS protection circuits.
  4. Never operate UPS in wet or humid conditions.
  5. Ensure proper ventilation around UPS and battery banks.
  6. Be aware that UPS output remains live even when mains fails.
  7. During maintenance, follow lockout-tagout (LOTO) procedures.

5. Pre-Operation Checks

1).. Visual Inspection:

  1. Check UPS for alarms, warning lights, or physical damage.
  2. Ensure batteries are free from swelling, leaks, or corrosion.

2).. Power Sources:

  1. Verify input (mains) voltage and frequency are within limits.
  2. Check generator readiness (if connected).

3).. Indicators & Alarms:

  1. Confirm UPS is in normal mode (mains supply with battery charging).
  2. Ensure no faults are active on display/control panel.

6. Operating Modes & Procedures

6.1 Normal Operation (Mains Available)

  1. UPS receives power from mains supply.
  2. Battery remains on float charging mode.
  3. Load is continuously supplied with conditioned power.
  4. Operator monitors:Input voltage, output voltage, frequency, load %, and battery status.

6.2 Power Failure (Mains Supply Lost)

  • UPS automatically switches to battery mode without interruption.
  • Critical load continues to run on battery power.
  • Operator should:
  1. Verify UPS alarms and battery runtime.
  2. Inform control room/supervisor.
  3. Start generator if backup is available.

6.3 Generator Synchronization

  • Once generator stabilizes, UPS automatically shifts to generator input.
  • Battery resumes charging mode.
  • Monitor:
  1. Generator voltage and frequency.
  2. UPS input/output readings.

6.4 Returning to Normal (Mains Restored)

  1. UPS automatically transfers input back to mains supply.
  2. Battery charging resumes.
  3. Monitor all indicators to ensure smooth transition.

6.5 Manual Bypass (for Maintenance)

  • Inform supervisor and control room.
  • Ensure load can tolerate transfer without risk.
  • Switch UPS to manual bypass mode.

  1. Load is supplied directly from mains (not protected by UPS).

  • Perform maintenance as required.
  • Return UPS to normal operation after checks.

7. Monitoring During Operation

  • Continuously monitor:

  1. Input voltage & frequency
  2. Output voltage & load percentage
  3. Battery status (charging/discharging/health)
  4. Alarms and fault indicators

  • Record all readings in UPS logbook at defined intervals.

8. Fault Handling

UPS Alarm or Fault Condition:

  • Identify alarm code from display/control panel.
  • If critical, transfer load to bypass supply.
  • Inform maintenance team immediately.

Overload Condition:

  • Disconnect non-critical loads.
  • If overload persists, UPS may transfer load to bypass.

Battery Low/Failure:

  • Reduce load to extend runtime.
  • Shut down non-essential loads until mains or generator is restored.

9. Shutdown Procedure

  1. Inform control room and end-users before shutdown.
  2. Switch UPS to bypass mode (load supplied by mains).
  3. Turn off UPS output breaker.
  4. Turn off UPS input breaker.
  5. Disconnect battery bank (if long-term shutdown).
  6. Record shutdown in the logbook.

10. Maintenance

  • Daily: Check UPS panel indicators, alarms, and log readings.
  • Monthly: Verify battery connections, ventilation, and environment.
  • Quarterly: Test UPS transfer (mains → battery → mains).
  • Annually: Full preventive maintenance (battery test, cleaning, calibration).

11. Documentation

  • UPS Logbook: Record input/output voltages, load %, battery status, and alarms.
  • Fault Reports: Document cause, action taken, and resolution.
  • Maintenance Records: Scheduled inspections and servicing details.

12. Best Practices

  • Never overload the UPS beyond rated capacity.
  • Test batteries periodically under load.
  • Keep UPS room temperature within manufacturer’s recommended range.
  • Maintain clear space for ventilation.
  • Regularly train staff on UPS operation and emergency handling.


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