Medium Voltage Covered Conductors

Standards

IS:398(Part-II), IS:398(Part-IV), IEC :61089, EN 50397-1:2006, BS EN 50182

Conductor

Wires used in the construction of stranded conductor are either of aluminium alloy (AAAC) or aluminium alloy steel reinforced (ACSR) and are longitudinally water tight by means of water blocking material. The water blocking material should remain stable at 90℃. The water blocking material is put while bunching the stranded conductor. Water blocking material should be compatible with the conductor & conductor screen. It should not have any adverse impact on the mechanical & electrical properties of conductor & its screen.

Conductor Screen

A semiconducting polymer screen is kept over the conductor to minimize the stresses of the conductor by smoothing its surface. This semiconducting layer is kept under the extruded insulation.

Insulation

A layer of Cross linked Polyethylene (XLPE) applied over the inner semiconducting screen as main insulation.

Outer Insulation

On the insulation a colored protective layer of UV resistant XLPE/HDPE is applied with anti-tracking properties.

The semiconducting screen, inner insulation and outer insulation are extruded in one step i.e. triple extrusion to ensure a good, permanent bond among the three layers and also with the conductor.

Technology

Covered conductor consists of multi strand round/compacted hard drawn aluminium alloy (AAAC) or aluminium conductor steel reinforced (ACSR) longitudinally water blocked & covered with special grades of materials which provide insulation & protection from UV rays. Like HT cables these conductors are provided with triple extrusion.

Description

Indian state utilities are making focused efforts for upgrading & strengthening medium voltage distribution lines in forest and wildlife sanctuaries to avoid fatal accidental death due to electrocution of wildlife birds & animals which come in contact with live overhead bare conductors. In last few decades we have noticed several electrocution cases in India.

1300 wild animals killed by electrocution in India within a decade: Report NGO Wildlife Protection Society of India As per data compiled by NGO Wildlife Protection Society of India (WPSI) between years 2010 to 2020 around 1300 wild animals lost their lives due to accidental electrocution.

In various states such as Odisha, Kerala, Karnataka, Andhra Pradesh, Maharashtra, Gujarat, Assam, Tamil Nadu, Chhattisgarh, Jharkhand, Uttar Pradesh, Uttarakhand etc. witnessed high animal fatalities due to electrocution.

The main concerns to the electrical utilities are:

• Power interruptions due to conductor slashing during wind and stormy conditions. • Power interruptions due to contact of tree branches and creepers with live overhead conductors.
• Electrocution of wild animals and ensuring safety in their natural habitat.
• High operation and maintenance cost.
• High electrical losses due to corrosion/oxidation of open conductor.
• Safety issue in congested residential areas.
• Wide Right of way.

At V-Marc India Limited, we have identified the need of Covered Conductors for the transmission of high voltage electrical power and taken the initiative to minimize the electrical losses. This also offers protection from accidental electrocution of wild life in their natural habitat.