Medium Voltage and High Voltage Cables: Design & Construction

Medium Voltage (MV) Cable

The International Electrotechnical Commission (IEC) defines medium voltage cables as having a voltage rating of greater than 1kV and less than 100kV. Znergy Cables is a major provider of medium voltage cables, which we define as those with a voltage range of 3.3kV to 45kV. To discover the suitable cable for your application at higher voltages, please see our high voltage cable specs. Our MV XLPE insulated cables are made to meet a variety of Australian and international standards.



Standard circular compact copper conductors, XLPE insulated, copper tape screened, constructed with non-hygroscopic polypropylene fillers, covered with tapped bedding unarmoured, and PVC sheathed shall be used in the medium voltage cable. IEC 502. Cables must be compliant.
Construction of MV Cable

Medium voltage cables shall be armoured, 15 KV XLPE insulated copper conductor cables having the following characteristics:

1. Conductor: Plain circular compacted copper conductor to IEC 228 Cl. 2.
2. Conductor screen: Extruded semi conductive compound.
3. Insulation: XLPE (cross linked polyethylene extruded and cross linked by silanc curing process rated 90 deg. C.
4. Insulation screen (non metallic part): Graphite layer covered with a lapping tape or extruded semi conductive material.
5. Insulation screen (metallic part): Copper tapes 0.10 mm thickness.
6. Bedding: Tapped bedding.
7. Armour: Galvanized steel tapes applied helically over the PVC bedding.
8. Outer sheath: PVC Type ST2 To IEC 502 Color Red.


APPLICABLE STANDARDS

The design of cables for use in the 13.8 KV network shall be based on IEC specification 502.


AUSTRALIAN CABLE TYPE DESIGNATION


N

MV cable according to DIN VDE 0276

A

Aluminium (Al) conductor

[blank]

Copper (Cu) conductor

2X

Cross-linked polyethylene (XLPE) insulation

S

Screen of copper wires and copper tape, helically wound

SE

Screen of copper wires and copper tape over each individual core, helically wound

Y

Polyvinyl Chloride (PVC) sheath

2Y

Polyethylene (PE) sheath

(F)2Y

Longitudinal water tightness with PE sheath

(FL)2Y

Longitudinal and transversal water tightness with Al/PE sheath


Our standard medium voltage cable portfolio, as a specialist MV cable supplier, includes cable with single and 3-core copper or aluminium conductors, steel or aluminium wire armour for mechanical protection, and various application-specific materials such as Polyvinyl Chloride (PVC), Polyethylene (PE), Cross-linked Polyethylene (XLPE), and Ethylene Propylene Rubber (EPR) (LSZH). We also offer medium voltage standard cables in triplex configuration, which are created to meet specific power network requirements. Our MV cable products are used in a variety of industries, including construction and power generation. They're frequently utilised for power distribution between high-voltage mains and low-voltage applications, as well as by utility companies to connect residential and industrial complexes to the major grid, as well as renewable energy sources like wind and solar farms.

Our MV cables come in a variety of lengths, including extended long lengths, to make installation easier and reduce the number of joints.


HV Cable - Design and Construction:


All cables shall conform to standards of IS 7098-1973, IS 1554-1976 and wiring cables to IS 694-1977


CONSTRUCTION OF HIGH VOLTAGE AND LOW VOLTAGE POWER CABLES

  1. All power and lighting cables shall be aluminium conductors, PVC insulated, armored and PVC sheathed. The insulation grade shall be 1100 V. The control cable shall be of copper conductor, PVC insulated, armored, and PVC sheathed of 1.1 KV grade.

  2. Wiring cables for lighting shall be multi strand, copper conductors, PVC insulated of 1.1. KV grade.

  3. The HT cables shall be of aluminium conductors, XLPE insulated and armored or as specified in the Bill of Quantities.


CONDUCTOR The current carrying capacity component is the most significant layer in cables, and it might be Copper or Aluminum. The conductor is made up of stranded soft drawn wires that are coiled together in one of two shapes:

1. Compacted circular conductor up to and including 800 mm2 for CSA

2. For CSA over 800 mm2, a segmented conductor with 5 segments is used.

CONDUCTORS WITHOUT WATER: The conductor can be made watertight upon request by putting swelling powder, yarns, or tapes within it (between conductor layers).

SCREEN FOR CONDUCTORS It's a thermoset semi-conducting substance that's been extruded to reduce the concentration of electric stress on the conductor surface due to the stranding. Before the conductor screen, semi-conductive tape might be utilised (it will be water blocked in case of water tight conductor).

INSULATION The cable's electrical protection is provided by an extruded and dry cured cross-linked polyethylene (XLPE) insulation layer. During its lifespan, the insulation should be able to withstand the rated voltage, lightning overvoltages, and switching overvoltages. The insulation material can withstand 90 degrees Celsius in normal operation and 250 degrees Celsius in short circuit situations.

SCREEN FOR INSULATION Over the insulation, it's an extruded thermoset semi-conducting substance. The three preceding layers (conductor screen, insulation, and insulation screen) are extruded in one operation on CV lines with several measurement equipment to ensure that the process is completely controlled.


SCREEN OF METALLIC METALLIC METALLIC METALLIC METALLIC This layer is the component that carries the current in a short circuit and can be one of the following types:

1. Copper wires bound with open helix copper tape

2. Sheath made of a lead alloy

3. A combination of the previous two options


JACKET ON THE OUTSIDE This is the final layer of protection for all within layers, and it might be any of the following:

1. Material made of PE (HDPE, LLDPE, MDPE)

2. Material: PVC

3. LS0H LS0H LS0H LS0H LS LAYER WITH SEMI-CONDUCTIVE PROPERTIES A semi-conductive coating, such as graphite powder or an extruded semi-conductive layer, to be put over the outer jacket for field testing following installation.


CABLE CONSTRUCTION

• Copper conductor, stranded, with round shape for cross-sections up to and including 800 sqmm and segmental for cross-sections 1000 sqmm and above.

• Inner semiconductor layer firmly bonded to the XLPE insulation.

• XLPE insulation.

• Outer semiconductor layer firmly bonded to the XLPE insulation (the inner semiconductor, XLPE insulation and outer semiconductor are extruded in one operation “Triple extrusion”).

• Copper wires screen with water blocking tapes.

• Aluminum laminated sheath.

• HDPE over sheath with semi-conductive layer.


SPECIAL FEATURES

• Copper wires screen: is the short circuit current carrying component.

• Water blocking tapes: is the longitudinal water barrier.

• Aluminum laminated Sheath: is the radial water barrier.


APPLICABLE STANDARDS

• IEC 60840 / ICEA S-108-720

• IEC 60949 & ICEA P-45-482


We also offer a full range of MV cable accessories, such as jointing kits, terminations, connectors, and lugs, to guarantee that our Medium Voltage cables work optimally as part of a system.


Australian Cable


Znergy Cables offers a wide range of high-voltage (HV) cable that meets Australian and international standards. We also offer customised HV cable solutions that are tailored to the individual needs of the applications and projects. This may necessitate uncommon volumes or lengths, short manufacturing lead times, and/or technically difficult constructions.

Our standard high voltage cables are intended for primary power distribution on networks having a 123kV voltage rating. On current catenary line equipment, HV cable is triple extruded to the latest IEC specifications using proprietary materials. They're ideal for cable protection setups that require mechanical protection. If the HV cable is damaged, waterblocking tape alternatives can assist keep the repair lengths and associated effort to a minimum. The standard material is high density polyethylene (HDPE), which provides a good balance of abrasion resistance and flexibility, but additional materials are available upon request.

HIGH VOLTAGE CABLE TECHNICAL SUPPORT

We supply high voltage cables with various alternative constructions and voltage ratings. Please contact our technical engineers to discuss your application and your project's specific requirements.

Construction Table

 

HIGH VOLTAGE / 2XS(F)2Y, A2XS(F)2Y 123KV POWER CABLE

HIGH VOLTAGE / 2XS(FL)2Y, A2XS(FL)2Y 123KV POWER CABLE

VOLTAGE

64/110kV

CONDUCTOR

Class 2 Copper or Aluminium, Compacted or Segment

CONDUCTOR SCREEN

Extruded semi-conductive XLPE (Cross-Linked Polyethylene)

INSULATION

XLPE (Cross-Linked Polyethylene)

INSULATION SCREEN

Extruded semi-conductive XLPE (Cross-Linked Polyethylene)

SEPARATOR

Water Swellable Semi-Conductive Tape

SCREEN

Copper Wire Screen, with a Counter Helix of Copper Tape

SEPARATOR 2

Water Swellable Tape

Water Swellable Semi-Conductive Tape

MOISTURE BARRIER

-

Aluminium or Copper Tape with Copolymer

OUTER SHEATH

HDPE (High Density Polyethylene)



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