Development of cold-shrinkable joints with carrier pipes for EHV cables

One piece, pre-molded joints have been used all over the world for extra high voltage (EHV) XLPE cables. For those premolded joints, ethylene-propylene rubber has mainly been applied for many years. We have succeeded in applying a new cold-shrink technology on those pre-molded joints by using silicone rubber which has lower elasticity and better mechanical properties, such as lower permanent set. With cold-shrink technology, pre-molded sleeves can be shipped expanded onto the carrier pipes. So the customer needs no tools for assembly at the jointing site and just needs to pull out the string of carrier pipes. All the type tests required on IEC standards 60840 were carried out including water immersion and heating cycle tests on our newly developed 110-132 kV cold-shrinkable joints (CSJ) and have shown good performance in all the tests, which means we became the first manufacturer ail over the world to develop cold-shrinkable joints (CSI) using silicone rubber for EHV XLPE cables