Auto reclose relays are essential parts of modern power systems, boosting system reliability and minimizing outage times.
The following post provides a complete checklist and step-by-step instructions for testing an auto reclose relay.
The checklist ensures that the relay functions correctly under defined conditions and meets utility regulations.
Consumer Information
The starting portion has fields for consumer data, location, serial number, relay make and type, substation, & bay information.
Accurate documenting of these parameters provides traceability and makes the test report consistent with operational records.
Test Equipment Details
Before starting testing, it is important to gather information on the test equipment requirements, which include:
- Type/Model:
- Calibration Date:
Certified & calibrated test tools assure reliability and adherence to quality requirements during testing.
Relay Information
Document the important relay requirements.
Relay Type:
Model Number:
Serial Number:
Rated Current (In)
Auxiliary Voltage(UAux):
VT Ratio:
This information is essential to ensuring that the relay setup meets the installation guidelines.
Preliminary Relay Checks
Before turning on the relay, conduct the following visual & wiring inspections:
| Check | Yes | No | Remarks |
| Visual Inspection | ☐ | ☐ | |
| Relay Damaged? | ☐ | ☐ | |
| Installation Ratings Verified? | ☐ | ☐ | |
| Case Earthing Installed? | ☐ | ☐ | |
| Test Block Connections Checked? | ☐ | ☐ |
A careful visual inspection of relay is required.
This includes inspecting for physical damage, verifying that all nameplate data and ratings are right for the installation, confirming that the case earthing is completed correctly, & ensuring that test block wiring & terminal connections are secure.
These pre-checks assist in detecting any installation faults (or) physical damage that may compromise test results or relay performance.
Relay Energization & LED Status Check
After applying the auxiliary voltage to the relay, confirm the device’s state. The healthy LED (typically green) should glow, indicating that the relay is energized and operational.
The alert LED (typically orange) & trip LED (red) need to be tested by resembling the appropriate conditions.
These LEDs act as the first line of feedback to ensure that the internal relay circuits are operational.
Secondary Injection Tests
The secondary injection test consists of applying synthetic voltage signals to the relay’s inputs at 25%, 50%, & 100% of nominal levels.
These values are fed into every voltage input (U1, U2, U3, & U4), and the relay’s response is evaluated.
The test confirms the relay’s voltage sensing accuracy & ensures the measuring circuitry’s integrity.
This step is essential for ensuring that the relay responds accurately to real-world voltage conditions.
Synchro-Check Testing
Auto reclose should only be enabled when the voltage, frequency, & phase angle between busbars & incoming feeders are synced.
- Kecheck the voltage difference to ensure it is within acceptable limits (e.g., ±10%).
- Frequency difference is typically between ±0.2 Hz.
- Phase Angle Difference – Typically set between 5° and 10°.
Ex: if the phase angle difference exceeds 15°, the relay must close to prevent equipment damage.
Dead Time and Reclaim Time Testing
Dead time is the time between a breaker trip & the first reclose action.
Reclaim Time is the time that the relay takes to reset following fault clearance or failed reclosing efforts.
Test Procedure: Set time values on relay (e.g., Dead Time = 1.0 sec, Reclaim Time = 15 sec).
Trigger relay & record real-time responses.
Expected deviation from set values is less than ±0.1 second.
Auto Reclose (AR) Shot Testing
Most AR relays can make several shot attempts (single, double, or triple shot).
Test Procedure: Simulate a trip condition.
Check if the relay initiates reclose attempts according to the configured shot count and timing.
Confirm relay prevents future shots following a persistent fault condition.
A relay with “3-shot” logic will reclose at regular intervals (e.g., 0.5s, 1s, 2s) & cease if the fault persists.
Final Functional Tests
After the Dynamic & Static Tests:
- Verify that the event record & fault oscillography are accurately captured.
- Confirm that all binary inputs/outputs operate according to the supplied logic.
- Check and set the correct time & date on the relay to ensure appropriate event timestamping.
- Test all LED indicators again to ensure complete status functionality.
Checklist
Conclusion
Following this detailed procedure ensures that the auto reclose relay is properly configured, operationally appropriate & meets system protection standards.
Each test from visual checks to AR shots helps to validate the relay’s function in ensuring system stability and safety.
