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Adapting Cable Accessories for Onshore & Offshore Substations

June 10, 2017 • ARTICLE ARCHIVE, Cable Accessories, Substation
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Dry Type Pluggable Solutions for On & Offshore Applications

Pluggable Accessories

Pluggable terminations, bushings and more such accessories have been significantly used in high voltage cable accessories now for years. More recently, the product range has been enlarged for further applications and been driven towards highest voltage levels (designed up to 550 kV).

In order to best meet the needs of transformer manufacturers (testing IEC 60137, housing EN 50299), GIS manufacturers (testing IEC 62271‑203, housing IEC 62271‑209) and cable manufacturers (testing IEC 60840 and IEC 62067), it is necessary to understand all their needs as well as any differences between these. In order to combine and best meet all requirements a wide product range is needed:

• Pluggable termination (separable socked and plug);
• Pluggable surge arrester;
• Pluggable SF6 filled back to back joint;
• Pluggable dry cast resin joint;
• Covering disc for pollution protection of the socked;
• Protective cap for pollution protection of the plug;
• Dummy plug for voltage insulation;
• Earthing and short circuit device;
• Earthing cap;
• Current testing cap;
• Gas-insulated blind cover.

Fig. 9: Connection between sea and tower cable in offshore wind power generation application. cable accessories Adapting Cable Accessories for Onshore & Offshore Substations Screen Shot 2016 07 15 at 14

Fig. 9: Connection between sea and tower cable in offshore wind power generation application.
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Dry Type Pluggable Cable Joints

Due to the increasing demand for offshore applications of HV cable accessories, a new dry type pluggable joint (back-to-back joint) has been developed. This kind of accessory combines the advantages of standard dry type pluggable terminations and joints while allowing easy connection between different cables. The main benefits include:

• Dry type design (no oil or gas insulation);
• Pluggable connection;
• Fast and easy installation with connectors;
• Compact design;
• Connection of two different types and sizes of cable;
• Resistance to salt water and UV radiation;
• Epoxy body fully ‘offshore proven’.

Fig. 9 shows an example of exploiting the advantages of this type of accessory by using it for the connection between the sea and tower cable in an offshore wind generation application.

Fig.10: Example of dry type pluggable joint. cable accessories Adapting Cable Accessories for Onshore & Offshore Substations Screen Shot 2016 07 15 at 14

Fig.10: Example of dry type pluggable joint.
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In order to fulfil the growing requirements placed on HV cable systems, the above advantages also allow use of a dry type, back-to-back joint for other applications, including:

• Refurbishing old HV cable system through connecting already installed and new cable;
• Temporary installation for construction sites;
• Back-up solution;
• Connection between test equipment and test objects (e.g. during commissioning).

The construction of this product has been successfully proven and certified for offshore use by several design tests as well as by additional type tests according to IEC 60840 for voltage levels up to Um=100 kV and conductor cross-sections up to 1600 mm2. Moreover, this same product for Um=170 kV has seen on-going development.

Fig. 11: Set-up for electrical test of dry type back-to-back joint cable accessories Adapting Cable Accessories for Onshore & Offshore Substations Screen Shot 2016 07 15 at 14

Fig. 11: Set-up for electrical test of dry type back-to-back joint.
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