When the sheaths are bonded at both ends, the eddy current losses in sheath will increase with the increase of the distance of cables.

• 当电缆金属套双端接地时，由于每相金属套间产生的电磁感应电势不相等，金属套中将产生环流损耗，此部分损耗甚至比电缆导体交流损耗还要大。