Study on on-line monitoring of cross-linked of metallic sheath of three-phase power cable insulation

The cross-linked power cable has the merit of less circulation circuit current of the shielding layer and is more economic and safe than the ordinary layout. But it is difficult to monitor the insulation situation of each segment of the electrical cable. The reason is that the current which flows cross the main insulation of each segment of the cable is hard to be got by direct measurement. In order to solve the problem, analyzing and introducing the shielding interconnection mode of three-phase power cable in detail. Through analyzing the interconnection mode, found that the conductor wire core is not cross-linked. A new method of on-line monitoring has been put forward, and the working principle is described in detail. Design on-line monitoring system based twin CT method. The experiment result is shown that the on-line monitoring system of the dielectric loss factor has high accuracy after comparing the data of measurement with the result of theoretical calculations, verifying the validity and correctness of the on-line monitoring system.