Abstract: A power cable includes a steel pipe coupled to a reference potential node, three transmission cables within the steel pipe and respectively including a conductor to transmit three-phase alternating current power, and a return cable within the steel pipe and coupled to the reference potential node. Each of the three transmission cables includes a first insulating layer covering the conductor, a metal layer covering the first insulating layer, and a second insulating layer covering the metal layer. The three transmission cables are twisted around a periphery of the return cable along a longitudinal direction of the return cable, and the metal layer is coupled to the reference potential node.

Abstract: An optical fiber temperature distribution measuring apparatus and a method for measuring optical fiber temperature distribution, provided with a light source for inputting a pulse light to an optical fiber to be measured, a signal detecting unit for detecting a received light intensity of a predetermined light included in a backscattering light generated by an input of the pulse light in the optical fiber to be measured, and a signal processing unit for calculating a value corresponding to a variation of the received light intensity due to a hydrogen molecular absorption of the optical fiber to be measured based on the received light intensity of the predetermined light, to compensate the received light intensity of the predetermined light corresponding to a temperature of the optical fiber to be measured based on the value.