Experimental Revision of the Multi-circuit Ampacity Correction Factor of Direct Buried 10 kV Three-core Cables

Cable load is adjusted according to its ampacity, therefore the accurate calculation of ampacity ensure the cable operate safely and reliably. For 10kV distribution cables (general three-core cable), the ampacity is the product of standard one (under standard condition) multiplying by its correction factor. Nowadays, more and more cable operation personnel question the applicability of those factors, especially the multi-circuit ampacity correction factor. A program calculating the ampacity of three-core cable with directly buried laying is developed. Ampacity tests of single and four circuit cable are undertaken in this paper. Test results shows consistent with that calculated, which verifies the correctness of the theoretical calculation. Studies show that the multicircuit ampacity correction factors used currently are too large and hreaten its operation safety. On the basis of calculation and experiments, this paper recommends the multi-circuit ampacity correction factors for the directly buried 10kV threecore cable.