Straight through cold-applied shrinkable EPDM cable joints designed for high stress medium voltage EPR cables

Abstract

The introduction of high electrical stress EPR insulated medium voltage cables leads to the development of new cable joints suitable for installation. This paper presents the joint design considerations and test data. The test program is based on IEEE Standard 404-1993. Test samples include joints for high stress EPR cables and transition joints from high stress EPR cables to PILC cables. All test results have shown that both joint designs comply with the IEEE standard and suitable for operation in cable network systems.

Long-term testing and applications of high-stress MV EPR cables

“…Further research [22] has indicated a need for a third variable in determining the minimum allowable insulation thickness. While this third variable is still related to voltage stress, it relates to the voltage stress at the insulation/insulation-shield interface.…”

“…The voltage stress at the conductor-shield/insulation is important to the capabilities of the insulation itself, but the stress at the insulation/insulation-shield interface is vital to the X THE 15-kV CLASS EPR INSULATION THICKNESS TABLE XI THE 25-kV CLASS EPR INSULATION THICKNESS TABLE XII THE 35-kV CLASS EPR INSULATION THICKNESS capabilities of the accessories that may be used in conjunction with the cable. The voltage stress limit at the insulation/insulation-shield interface based on this research [22] was established as a maximum of 2.4 kV/mm (61 V/mil). This value was determined based on positive test results on a 750-kcm, 3.18-mm (125-mil) cable.…”

“…Further research on reduced diameter cables based on maximum electrical stress, mechanical integrity, and accessory development seemed like a reasonable approach and one that might provide the reduced diameter cables needed by Ameren [1], [2], [22].…”