Perform Earth Leakage Injection Tests with Sverker760
Purpose:
How to perform Earth Leakage injection tests with Sverker760 to help ensure zero harm to people, community, the environment or business processes.
PPE：
Site PPE；LV rescue kit
Equipment：
Electricians toolkit；Sverker760 (04-00117)；Jumper lead kit；Certified and calibrated multimeter
Materials：
Barricade tape and info tags；Camera；Torch
Task Preparation：
1. Conduct a Take 5.
2. Barricade area where testing will take place and place information tags.
3. Ensure adequate communication and notice has been given to the people and/or parties that will be affected by the removal of power from the circuit to be tested.
Check that the circuit is OK to be tested
Familiarise Yourself with the Sverker760 Unit and Features you will be Using
The Sverker760 injection tests included in this SWI are:
• Open CT Test.
• Instantaneous Test.
• Current Pick up Test.
• Time Delay Test.
The current source built into the Sverker can provide 0-10A, 0-40A or 0-100A. Timing and generation outputs can be carried out at the same time. When the relay being tested trips, both output and timing are interrupted.
Push Button Test
1. Perform push button test on earth leakage (EL) relay to trip.
2. Confirm EL relay has tripped.
3. Open MCC enclosure and test for dead.
Valid CPR and LV rescue competencies are required for this task
Record Earth Leakage Relay Details and Settings
1. Record the EL relay’s make, type (ie. Ampcontrol, ELM) and serial number.
2. Record the trip level (mA) and the trip delay (ms) settings on the EL relay.
3. Inspect the connections and take a photo to later revert to original configuration.
Set up Sverker760
1. Check Sverker760 unit is within calibration date and power lead is tested and tagged.
2. Set up Sverker760 unit within reach of the EL relay.
3. Connect the leads as per below configuration steps.
Ensure LV rescue kit is complete and accessible and the work area is clear of trip hazards
Connection
1. Connect jumper lead from neutral current source to the ammeter current output as seen below.
2. Connect jumper lead from the other ammeter current source to the bottom terminal of the resistor set as seen below.
3.Connect jumper lead from the upper terminal of the resistor set, pass through the earth leakage toroid and connect to the 0-10 current output as seen below.
4. Connect two jumper leads to the “STOP input” terminals as seen below. These leads will be connected to the shunt trip of the EL relay.
5. Connect the other end of the jumper leads from the “STOP input” terminals (from previous step) to the shunt trip of the EL relay as seen in examples below.
All connections are now finished and the circuit is complete.
Open CT Test
Valid CPR and LV rescue competencies are required for this task
Simulating an open circuit in the cabling to the EL toroid. This test shall result in a EL relay trip with a time of under 5s (AS2081 clause 6.4).
1. Turn on Sverker760.
2. Ensure the main knob on the Sverker760 is wound all the way to zero.
Press SEL button (marked A below the bottom right corner of the LED display) until the ammeter current output is selected. Ammeter current output LED labelled A will come on.
If the EL relay does not trip during this test, Turn Sverker760 OFF and start again ensuring the EL relay is healthy and not showing a trip. Reset trip where necessary
3. Ensure the EL relay is healthy and not showing a trip. Reset if necessary.
4. Locate the UP arrow button on the Sverker760 located just below and to the left of the SEL button. Locate the terminals on the EL relay which go to the EL toroid.
5. At the same time, pull out the EL toroid terminals from the EL relay and press the up button. The timer will start.
6. The EL relay should trip within 5 seconds. The TRIP light and the OFF light on the Sverker760 will turn on and the ON+TIME light will turn off. Record the trip time (s) on the top left of the LED display.
Instantaneous Test
The Instantaneous Test tests the minimum operating time of the EL relay and should be no greater than 50ms (AS2081 clause 6.3.2).
1. Ensure the OFF light next to the UP arrow on the Sverker760 is illuminated.
2. Ensure the main knob on the Sverker760 is wound all the way to zero.
3. Ensure the EL relay is healthy and not showing a trip. Reset if necessary.
4. Wind trip level (mA) and the trip delay (ms) settings on the EL relay down to the minimum.
5. Wind main knob on Sverker760 to 150% of the trip level (mA). (ie. if trip level is set at 100mA, wind knob up to 0.150A).
6. Press UP arrow to start test.
7. The EL relay should trip instantaneously. The TRIP light and the OFF light on the Sverker760 will turn on and the ON+TIME light will turn off.
8. Record the trip time (ms) on the top left of the LED display.
9. Wind the main knob on the Sverker 760 back to zero.
10. Wind trip level (mA) and the trip delay (ms) settings on the EL relay back original positions.
11. Reset the trip.
Current Pick up Test
The Current Pick up Test tests the EL relay’s capability of accurately sensing and tripping a circuit where the fault current ranges from less than 0.1A up to 5A. The trip level (mA) result from this test should have an accurracy of +/-10% of the trip level setting (mA). (AS2081 clause 6.2).
1. Ensure the OFF light next to the UP arrow on the Sverker760 is illuminated.
2. Ensure the main knob on the Sverker760 is wound all the way to zero.
3. Ensure the EL relay is healthy and not showing a trip. Reset if necessary.
4. Press UP arrow to start test.
5. Slowly turn the main knob on the Sverker760 up until the EL relay trips. Once the EL relay trips, the TRIP light and the OFF light on the Sverker760 will turn on and the ON+TIME light will turn off.
6. Record the trip level (mA) on the bottom left of the LED display. Ignore the trip time (s) for this test.
7. Reset the trip.
Time Delay Test
The Time Delay Test tests the maximum delay time achievable by the EL relay associated with the trip level (mA) setting. The trip time (ms) result from this test should have an accurracy of -20% +0% of the trip time (ms) setting (AS2081 clauses 6.3.3 & 10.6.2.3).
1. Ensure the EL relay is healthy and not showing a trip. Reset if necessary.
2. Ensure the Sverker OFF light is illuminated and the ON+TIME light is off.
3. Wind the main knob on the Sverker760 up until the bottom left value on the LCD display shows 150% of the EL relay trip level (mA) (ie. if trip level is set at 100mA, wind knob up to 0.150A).
4. Press UP arrow to start test.
5. The EL relay should trip almost instantaneously. The TRIP light and the OFF light on the Sverker760 will turn on and the ON+TIME light will turn off.
6. Record trip time (ms) shown on the top left of the LED display.
7. Wind the main knob on the Sverker760 back to zero.
8. Reset the trip.
9. Turn Sverker760 off.
10. All Sverker760 injection tests are now complete.
Push Button Test
1. Once again, perform push button test on earth leakage (EL) relay to trip.
2. Confirm EL relay has tripped.
3. Reset trip
Review Results
1. Review results against acceptance criteria and notify supervisor of any EL relays that do not meet this criteria.
2. Discuss with supervisor and reliability engineer before altering any EL relay protection settings.
Return to Service
1. Remove tools and equipment.
2. Return EL relay settings and connections to original configurations.
3. Advise person in control of the area that the task is done and the equipment is available for return to service.
Complete job documentation and return to supervisor and advise task is done.
Standards
AS/NZS 3000 Wiring Rules
AS/NZS3007 (Electrical equipment in mines and quarries - Surface installations and associated processing plant)
AS/NZS2081 Electrical protection devices for mines and quarries
AS/NZS4871.1 Electrical equipment for mines and quarries - Part 1 General requirements
AS2225 Insulating gloves for electrical purposes