I. Purpose & Scope

To safely and effectively provide instruction on the inspection and proper use of compressors.

II. Definitions

Standard PPE – High Viz Garment, Hard Hat, Z-87.1 Safety Glasses, Gloves, Pants, Work Boots

III. Process

NOTE: Work instruction does not supplement the manual. For specific instructions for the exact model please refer to the owner’s manual.

A. Potential Hazards

• Electric Shock Hazard
• Arc Flash Hazard

B. PPE

• Standard PPE

C. Inspection

1. Inspect and clean connectors and connections.
2. Inspect and report any damage. Do not use damaged equipment.

D. Use

Power on the System

1. Press the On/Off button to start up the system.
2. Navigate within the menus by turning the rotary knob. When the menu item is selected by being circled in red click the knob to confirm (selecting enter) selection.

High Voltage Control

1. Before starting any HV test, the user is prompted to enable high voltage, by pushing the green illuminated HV ON button.
2. The red illuminated HV OFF button signals that the HV output is now energized and the green button goes dark.
3. The high voltage can be switched off any time during the course of the test by pushing the HV OFF button. The test is then immediately aborted, and the high voltage power supply is turned off and the entire test circuit including the EZ Thump is discharged and grounded, which is indicated by grounding symbol in the upper left-hand corner of the LCD screen.

Conditions of the Safety Circuit

1. The following safety conditions must be met to allow to perform tests under high voltage:
   • The HV key switch must be in the power position.
   • The emergency off button must be unlocked (up).
   • The F-Ohm safety circuit must have a loop resistance below 6.5 ohms (if resistance is high, warning on LCD will be provided and system will lock out any HV applications).
     NOTE: If the HV application is disabled because of one or more of these conditions are not being met, they must be eliminated, and the message must be acknowledged before HV ON can be enabled again.

Locating a Faulting Cable Segment (Sectionalizing)

1. Determine the distance to the end of the cable or an open point in the circuit (blue trace, live trace).
2. Determine the distance to the fault using the ARM method (red trace, frozen).
3. Determine the number of transformers up to the fault and one beyond it.
4. Based on relative position of fault to the 2 closest transformers the faulted cable segment can be identified and easily isolated.
5. Select the Search icon menu item from the main menu or from the measure submenu.
6. Select the arrow to start the fault location.
7. Adjust the surge voltage and select the checkmark to confirm the value (not required in automatic mode).
8. Press the green illuminated HV ON button.
9. Select the arrow to charge the surge capacitor (only if measurement start option is set to manual).
10. Select the arrow to discharge capacity.
    • If a voltage breakdown takes place, the red fault trace is shown in the display. The red fault marker is automatically set to the position where both traces diverge from each other. The fault is referenced to the 2 closest transformers, which identify the cable section containing the fault.
      NOTE: If no trigger is received and, thus, no fault trace is shown, you may try to repeat the procedure with a higher surge voltage (if possible) by select the repeat icon.
11. Select the arrow to identify transformers.

How to Verify a Faulted Cable Section

1. Select the electric level menu item from the main menu or from the check level submenu.
2. Adjust the test voltage and select the checkmark to confirm the value.
3. Press the green illuminated HV ON button.
4. Select the arrow to start the test. (only if automatic voltage release option is set to manual).
   • Breakdown at…kV – A voltage breakdown took place at the indicated test voltage.
   • No Flash-over – The cable has withstood the applied DC test voltage. If possible, (repeat) the test with higher voltage (do not exceed the maximum permissible voltage).
   • Cable not chargeable – The cable could not be charged by the test voltage. This is typically due to a short (fault) in the cable, creating maximum current output.
   • Low resistance at…kV – The HV source cannot charge the cable beyond the indicated voltage value due to the substantial leakage current level.
5. Select the X to return to the main menu.

How to Test the Dielectric Strength of the Cable

1. Select the electric level menu item from the main menu or from the check level submenu.
2. Adjust the test voltage and select the checkmark to confirm the value if on manual voltage control.
3. Press the green illuminated HV ON button.
4. Select the arrow button to start the test.
   • Breakdown at…kV – A voltage breakdown took place at the indicated test voltage, meaning there was a flash-over at the fault.
   • No Flash-over – The cable has withstood the applied DC test voltage. In this case no current will be indicated. If required, repeat the test with high voltage (do not exceed the maximum permissible voltage).
   • Cable not Chargeable – The cable could not be charged while the test voltage was applied. This is typically caused by a short circuit condition in the cable (zero voltage and max current).
   • Low resistance at…kV …MΩ – The HV source cannot charge the cable beyond the indicated voltage value due to a substantial leakage current level; this indicates a very low resistance fault (some voltage and high current). The voltage indication must not be interpreted as a flash-over voltage, it is merely the voltage that the HVPS can build given the high leakage current.
5. Select arrow to proceed with fault pre-location or X to return to the main menu.

Arc Reflection Method (ARM)

1. Select the Locate menu item from the main screen or from the submenu screen.
2. Select the arrow to start fault trace (fault pre-location).
   • If required, the surge voltage can be adjusted via the gear icon, otherwise, the maximum surge voltage is automatically used, if automatic voltage control has been selected as default.
3. Press the green illuminated HV ON button.
4. Select the arrow to charge the capacitor (only if automatic high voltage release options is set to manual).
5. Select the arrow to discharge the capacitor (only if automatic high voltage release option is set to manual).
   • If necessary, adjust the display settings, TDR settings and marker position through the gear menu in order to identify the fault distance as precisely as possible.
6. Select the arrow to proceed with pinpointing or X to return to the main screen.

How to Pinpoint a High Resistance (Flash-over) Fault

1. Select the flashover icon item from the main screen.
2. Adjust the surge voltage and select checkmark to confirm the value.
3. Press the green illuminated HV ON button.
4. Select the arrow to start the thumping mode (only if automatic voltage release option is set to manual).
5. Pinpoint the fault within the pre-located area with a surge wave receiver like the Megger Digiphone Plus.
   NOTE: For detailed instructions, please refer to the user manual of the surge wave receiver.
6. Select X to stop thumping.

Sheath Test

1. Select the Sheath menu item from the voltage checkmark submenu.
2. Confirm the following two notices with checkmarks.
3. Adjust the test voltage and select checkmark to confirm the value.
4. Press the green illuminated HV ON button.
5. Select the arrow to start the test (only if automatic voltage release option is set to manual).
   • Breakdown at…kV – A voltage breakdown took place at the indicated test voltage.
   • No Flash-over – The cable jacket has withstood the applied DC test voltage. The test can be repeasted with the repeat menu item.
   • Charge not Chargeable – The cable shield could not be charged iwth the test voltage. This is caused by a short in the circuit (fault in the jacket).
   • Low resistance at…kV….MΩ – The HV source cannot charge the cable beyond the indicated voltage value due to a substantial leakage current level; this indicates a very low resistance fault (some voltage and high current). The voltage indication must not be interpreted as a flash-over voltage, it is merely the voltage that the HVPS can build given the high leakage current.
6. Select the arrow to proceed with sheath fault pinpointing or X to return to the main menu.

How to Pinpoint a Sheath Fault in a Shielded Medium Voltage cable or a Ground Fault in an Unshielded Low Voltage Cable (both must be directly buried)

1. Select the sheath menu item from the submenu.
2. Confirm the following two notices with checkmarks.
3. Adjust the surge voltage and select checkmark to confirm the value.
4. Press the green illuminated HV ON button.
5. Select the arrow to start the sheath fault pinpointing mode. The voltage selection, automatic should be disabled.
6. Pinpoint the sheath fault with an earth fault located like the Megger ESG-NT.
   NOTE: For detailed instructions, please refer to the user manual of the earth fault locator.
7. Select X to stop pulsing.

E. Maintenance

1. Keep connectors and connections clean.
2. Keep device free of dust and debris and keep dry.

IV. Reference Documents

Megger EZ Thump Operator Manual