๐ TRAINING MODULE
๐ HT Cable Testing
Types • Procedures • Standards • Field Best Practices
๐ฆ SLIDE 1 – Title Slide
HT Cable Testing & Commissioning
Ensuring Safety, Reliability & Compliance
For: Testing / Commissioning / O&M Engineers
๐ฆ SLIDE 2 – Learning Objectives
By the end of this session, engineers will understand:
✔ HT cable construction & voltage classes
✔ Mandatory pre-commissioning tests
✔ Test procedures & acceptance criteria
✔ Safety precautions during HV testing
✔ Field best practices & common failure causes
๐ฆ SLIDE 3 – What is an HT Cable?
HT (High Tension) Cable:
Used for power transmission typically from 3.3 kV to 33 kV
Common Voltage Ratings:
3.3 kV
6.6 kV
11 kV
22 kV
33 kV
Insulation Types:
XLPE (Most common today)
PVC (Older installations)
Applications:
Substations
Solar Plants
Industrial Feeders
Underground Distribution
๐ฆ SLIDE 4 – Why Testing is Mandatory?
HT cable failures usually occur due to:
❌ Moisture ingress
❌ Poor jointing/termination
❌ Mechanical damage during laying
❌ Overheating
❌ Insulation degradation
Testing ensures:
✔ Dielectric strength
✔ Insulation integrity
✔ Safe energization
✔ Compliance with IEC / IS standards
๐งช TECHNICAL TESTING MODULE
๐ฆ SLIDE 5 – Insulation Resistance (IR) Test
Equipment:
5 kV / 10 kV Megger
Test Connections:
Phase ↔ Phase
Phase ↔ Earth
Acceptance:
≥ 1 Gฮฉ (1000 Mฮฉ)
Key Principle:
Higher IR value = better insulation condition
๐ฆ SLIDE 6 – Polarization Index (If Required)
PI = IR (10 min) / IR (1 min)
✔ PI > 2 → Healthy
⚠ 1.5 – 2 → Monitor
❌ < 1.5 → Investigate
Indicates moisture & long-term insulation condition.
๐ฆ SLIDE 7 – High Voltage (Hi-Pot) Test
Purpose:
✔ Detect weak insulation
✔ Confirm dielectric strength
Method:
AC or DC voltage applied above rated voltage
As per IEC / IS standards
⚠ DC testing not recommended for aged XLPE cables.
๐ฆ SLIDE 8 – VLF (Very Low Frequency) Test
Frequency:
0.1 Hz
Advantages:
✔ Safer for XLPE
✔ Suitable for long cables
✔ Reduced stress compared to DC
Industry-preferred method for modern installations.
๐ฆ SLIDE 9 – Sheath Integrity Test
Purpose:
✔ Detect outer sheath damage
✔ Prevent moisture ingress
✔ Avoid earth leakage faults
Critical for underground systems.
๐ฆ SLIDE 10 – Continuity & Phasing Test
✔ Verifies core continuity
✔ Ensures no open circuits
✔ Confirms correct R-Y-B phase sequence
✔ Prevents wrong rotation & misconnection
Must be done before final termination.
๐ SAFETY MODULE
๐ฆ SLIDE 11 – Safety During HT Testing
Before testing:
✔ Obtain PTW (Permit to Work)
✔ Isolate & lockout
✔ Proper earthing
✔ Barricading & signage
After testing:
⚠ Fully discharge cable
⚠ Confirm zero potential
⚠ Remove temporary earths safely
Only authorized personnel allowed.
๐ PRACTICAL FIELD GUIDELINES
๐ฆ SLIDE 12 – Pre-Test Checklist
✔ Cable laying completed
✔ Proper glanding & termination
✔ Cable tags verified
✔ Test instrument calibration valid
✔ Ambient temperature recorded
๐ฆ SLIDE 13 – Common Failure Indicators
Low IR value
Fluctuating readings
Sudden breakdown during Hi-Pot
High leakage current
Sheath failure alarms
Immediate investigation required.
๐ฆ SLIDE 14 – Documentation & Reporting
Test report must include:
✔ Cable details (Size, Type, Length)
✔ Test voltage applied
✔ Duration of test
✔ IR values (1 min / 10 min)
✔ Ambient temperature
✔ Engineer signature
Trend analysis improves predictive maintenance.
๐ฆ SLIDE 15 – Key Takeaway
HT Cable Testing =
✔ Safety assurance
✔ Asset protection
✔ Reliability enhancement
✔ Compliance validation
✔ Prevention of costly outages
Testing is not a formality —
It is a commissioning responsibility.
๐ฏ Optional Add-ons I Can Create for You:
๐ Editable PowerPoint (.pptx) file
๐ Site-ready Test Report format (Excel)
๐ง Advanced Training Version (with failure case studies)
๐ฅ Animated Training Video version
๐ IEC / IS Standard Reference Slide
Since you're working in electrical measurements & systems, I can also add deeper technical calculations (leakage current analysis, test voltage formula, capacitance impact on VLF) if needed.
Tell me your target level:
Junior Engineers / Site Supervisors / Senior Commissioning Engineers ๐
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