TEDAŞ-MLZ/96-018.B Technical Specification for Medium-Voltage Cross-Linked Polyethylene (XLPE) Insulated Power Cables

Overview

TEDAŞ-MLZ/96-018.B is the technical specification for medium-voltage cross-linked polyethylene (XLPE) insulated power cables, published by Türkiye Elektrik Dağıtım A.Ş. (TEDAŞ). It covers cables rated 3.6/6 (7.2), 6/10 (12), 8.7/15 (17.5) and 20.3/35 (42) kV (clause 1.1). The current issue is Amendment A1 of April 2015; the first issue dates from May 1996 and the second revision from February 2006.

The construction section (clause 2.2) covers the elements of the cables: conductor screen, insulation, metallic screen, armour options, outer sheath and watertight variants. This content describes which layers make up a cable in terms of mechanical and environmental robustness, not only electrical performance. For a designer choosing from a cable catalogue, this section is the first point of reference for deciding which construction option suits which installation condition.

The specification gives the maximum conductor temperature as 90 C in normal operation and 250 C under short circuit, for a maximum of 5 seconds (clause 2.2.2). These two values are used directly when verifying a cable cross-section for continuous current and short-circuit withstand. In the adiabatic short-circuit check in particular, the 250 C upper limit for XLPE is the basis, so cross-section selection is tied to the trip times of protection relays and breakers, and thus to short-circuit and selectivity calculations.

The specification also covers tests, but this record does not hold test details and uses only the summary in the record. Related documents include IEC 60502-2, HD 620 and the Elektrik Şebeke Yönetmeliği. As a limit, the document was prepared for materials connected to the TEDAŞ network; the particular needs of a data centre (for example fire behaviour or high current-carrying capacity) may require additional criteria, and the specification should be read together with the manufacturer's technical data.

Key points

1. Covers XLPE-insulated cables rated 3.6/6 (7.2), 6/10 (12), 8.7/15 (17.5) and 20.3/35 (42) kV.
2. Maximum conductor temperature is 90 C in normal operation and 250 C under short circuit (max 5 s).
3. Construction: conductor screen, insulation, metallic screen, armour options, outer sheath and watertight variants.
4. Current issue: Amendment A1, April 2015; 2nd revision February 2006, first issue May 1996.
5. The typical reference in Turkey for MV feeder cables to data centre substations.
6. Related documents: IEC 60502-2, HD 620, Elektrik Şebeke Yönetmeliği.

Using it in design

• In MV cable sizing (TR profile), use the 90 C continuous and 250 C short-circuit limits for XLPE in the adiabatic short-circuit check.
• Offer the TEDAŞ voltage grades in the cable catalogue, for example 20.3/35 kV for 34.5 kV networks.
• Show watertight construction variants as an option on routes with water ingress risk.
• Select armour and sheath from the specification's construction options according to the installation conditions.

Who should read it

Electrical engineers designing MV feeds to data centre substations in Turkey, and specialists writing cable material specifications.

Related standards

• IEC 60502-2
• HD 620
• Elektrik Şebeke Yönetmeliği

Publication details

Authors

Türkiye Elektrik Dağıtım A.Ş. (TEDAŞ)

Publisher

Türkiye Elektrik Dağıtım A.Ş. (TEDAŞ)

Year

2015

Document number

TEDAŞ-MLZ/96-018.B

Document language

Turkish

Source type

Turkish regulation

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation