Pre Commissioning Test Procedure for High Voltage Cable

Purpose

This method statement is designed to carry out numerous pre-commissioning tests for switchgears in a systematic manner to assure the healthiness & performance of the HV cable.

Scope

This procedure covers the pre-commissioning test for HV cables, including

1. High Voltage (Hi-Pot) test,
2. Insulation Resistance test.

Personal Protective Equipment (PPE)

• Safety Helmet
• PPE Kit
• Hand Gloves
• Safety Shoes
• Safety Glass

Responsibility

Unit Heads/Regional Managers

Unit Heads/Regional Managers are responsible for health & safety management, 

1. Including planning and scheduling activities, 
2. Identifying and minimizing hazards, 
3. Adhering to legal and statutory requirements, 
4. Assisting the safety team with training and audits, and 
5. Ensuring compliance with safety rules and regulations.

Site Engineers

Site engineers are responsible for all areas of on-site health and safety and report to the Unit head / Regional Manager. 

Their responsibilities include:

1. Report any health and safety issues at work sites to the regional manager, unit head, or safety team. 
2. Coordinate with clients to obtain and return work permits. 
3. Communicate work content and hazards to working groups through meetings before each day’s start. 
4. Implement proactive measures to reduce accidents. 
5. Report incidents in detail.
6. Use “Stop Work” in case of major safety violations.

Safety Engineers

Safety managers and regional safety engineers are in charge of giving health & safety advice & direction to their unit head, regional manager, and site engineers. 

Their responsibilities include:

1. Communicate all safety rules, regulations, and procedures to site engineers, regional managers, and unit heads.
2. Follow up on audit non-conformances and assist regional managers/unit heads in taking remedial and preventive measures. Report and investigate any occurrences or near misses to high management.
3. Create awareness among site engineers and regional managers, and plan a regular training program.
4. Conduct daily toolbox discussion sessions to ensure workers are knowledgeable of workplace hazards.
5. Ensure suitable PPE and safety equipment are available and used on-site.
6. Report any problems affecting the health & safety at the work site to the unit head/regional management.
7. Ensure that fundamental first aid facilities are provided on site.
8. Ensure no harmful acts are undertaken on any site.
9. Eliminating harmful conditions on-site promptly. 
10. Issuing safety challans for any violations.

Work Activity & Descriptions

Pre-Testing Checks

1. Check the operating status of the ELCB (30 mA).
2. Inspect power cable insulation for equipment.
3. Ensure suitable earthing and rubber matting are accessible at the worksite.
4. Use calibrated testing equipment and provide engineers with calibration results.
5. Check the technician’s insulation hand tools.
6. Check the test leads for insulation damage.
7. Make sure proper PPE is provided at the site. 
8. Human supervision is required at both ends of the cable.

Resources: Tools and Equipment Required

For High Voltage Testing (Hi-pot test)

• High Voltage Test Kit 
• Test Leads
• Insulation Tester (500 and 5000 V)
• Clamp meter and Insulated Hand Tools.

For Insulation Resistance Measurement Test (IR Test)

• Clamp meter
• Test Leads.
• Insulation tester (500-5000 V)
• Insulated hand tools

Test Procedure

Step-1: Visual & Mechanical Inspection 

• Compare the cable data to the designs and requirements. 
• Check exposed parts of cables for the physical damage. 
• Inspect compression-applied connections for proper cable alignment and indentation. 
• Inspect the shield grounding, cable supports, and terminations. 
• Ensure that visible cable bends meet (or) exceed the ICEA and manufacturer’s minimum published bending radius. 
• Inspect the fireproofing in the common cable places. 
• If cables are terminated via window-type current transformers, inspect to ensure that neutral & ground conductors are correctly arranged and shields are correctly terminated for the operation of protective devices.
• Inspect for proper identification and organization. 
• Check the cable jacket & insulation condition.

Step-2: Insulation Resistance (IR) Test for EHV Cables

• Obtain a work permission from the client.
• Ensure there is no energy in high voltage (HV) cable.

Step-3: IR between Phase to Phase

• Connect the first conductor for measuring cross insulation to the megger’s line terminal.
• Connect the remaining conductor to the earth. 
• Connect the sheat to the earth terminal of the megger. 
• Leave the conductor at the other end free. 
• Turn on the megger and press the test button. 
• Discharge the potential with a separate earth rod. 
• Turn OFF the megger. 
• Repeat for the other conductors.

Step-4: IR between Phase to Earth

• Attach the conductor to the megger’s line terminal.
• Attach the guard to the last remaining conductor.
• Loop the armor and shielded conductor to the soil at the closest place and in the megger.
• Repeat the previous steps for the additional conductors. 
• Leave the other end free.
• Turn the megger ON & press the test button to record the reading.
• Discharge the potential using a separate earth rod.
• Turn the megger OFF.

Step-5: High Voltage (Hi-Pot) Test: HV Cable

• Obtain the client’s work permit.
• Ensure the bus bar terminal has no voltage and is earthed.
• During high voltage testing, earth all equipment associated to cable installation, including switches, instrument transformers, and busbars, and maintain clearance from other equipment and framework to minimize flashovers.
• Attach the Hi-Pot kit with the ELCB 30mA. 
• Connect the test lead to the conductor and cable armor.
• Connect the other conductors (other phase) to the ground. Then, turn on the test kit, apply voltage to the cable, and take the reading. Finally, use a discharge rod to discharge the cable potential.
• Connect the clamp meter to the discharge rod, touching the cable points, to ensure zero voltage.
• Perform the preceding methods to measure the other phases.

Control Measures 

• Testing engineers provide OCP for IR and Hi-Pot tests for HV cables.
• Make sure PTW system in setup for the specific bay.
• Ensure equipment supply is dead. 
• Prevent unauthorized access to the testing area. 
• Barricade the area with warning tape. 
• Conduct job-specific toolbox meetings and supervise the area. 
• Use calibrated equipment and insulated hand tools. 
• Avoid power cable joints and supply via ELCB.
• Avoid working alone. 
• Wear arc flash suits and avoid high-potential tests. 
• Use proper insulated hand gloves.

Final Inspections & Area Restoration after Work Completion

• Remove the barricading tapes and disconnect the temporary supply.
• Make sure that the space is free of any loose materials or tools.
• As you depart, make sure the area is neat and clean.

Communication & Sign-off Register

Communicate to all staff in meetings, and ensure that all personnel sign it.