Medium Voltage Termination Installation

Medium voltage termination installation is the termination of XLPE insulated cable routes at equipment connection points (cells, transformers, motors, joint bays) and the joining of two cable ends. The great majority of MV field failures happen in terminations rather than the cable body — because a head is both the weakest dielectric that can be installed and the densest craft point. A correct head is the engineering component that rebuilds the electrical-field continuity of the cable layers (semiconductive screen, XLPE, metallic screen, armour), softens the voltage stress and closes out environmental effects.

Termination Types and Selection

• Heat-shrink: The inner meltable adhesive layer forms an air-void-free barrier; heat gun-temperature-time protocol and cooling discipline decide quality; indoor-joint-bay type.
• Slip-on cold shrink: Pre-assembled elastomer structure; fast application with clean surfaces and correct inner-liner thickness; relaxation behaviour must be monitored.
• Pre-moulded: Factory-vulcanised stress cones; the most reliable field dielectric continuity, with critical mounting dimension tolerance.
• By location: Tree-porcelain outdoor ends (creepage-schematic control), indoor type, separable plug-in terminals (transformer-cell interface) and pothead-stress bodies (GIS bushing cones). Detailed route work sits in our MV cable installation service.

Craft Control Points

Head quality hides in five parameters: (1) Strip depth — no blade marks or scratches on the semiconductive layer, a sharp edge is where micro-discharge starts; (2) Cleanliness — carbon traces on XLPE removed with acetone-lint-free cloth, dust and fingerprints forbidden; (3) Stress control element — semiconductive-stress cone softens the field concentration at the screen cut-back to schematic dimensions and position; (4) Earth screen bond — braided earth wire-clamp continuity of armour-metallic screen at high-current section; (5) Barrier seals — cutting water-condensation creep outdoors. Craft runs on manufacturer instruction, qualified personnel and independent visual-measurement intermediate checks; every head enters the record with a asset identity label.

Testing and Certification

Post-head verification: insulation resistance per core, phase-earth dielectric integrity, screen-earthing continuity and on-site voltage test (stepped DC/VLF or AC resonance to HD 620.1.S1 values). PD measurement catches craft errors before energisation, especially in indoor heads. Thermography (thermal control) feeds the live contact-weak joint scan and results tie into the commissioning protocol. Heads carry TS EN ISO 11444 / HD 630 type-testing and are applied under Law No. 6331-EKA site rules.

Outcome

Termination work is planned within the earthing (EKA), cable pulling equipment and energy-isolation-permit chain. For cable head installation or test-inspection of existing heads contact us via the contact page; this service sits under MV Contracting.

Maintenance and Monitoring

Terminations may look like sealed, static parts but age with moisture, dust, thermo-mechanical cycling and partial discharge. The periodic audit reviews contamination on outdoor heads with leakage-current monitoring, shrink-surface colour-thermal analysis indoors and clamp tightness; suspect heads are verified unloaded with VLF-PD. An accessory compatibility table and spare-head stock cut intervention time from hours to minutes, and asset-based records form the administrative spine of this monitoring.