Electromagnetic compatibility of underwater high voltage cable lines with ichtiofauna

While designing underwater cable lines it is necessary to take into account the influence of an electromagnetic field in water environment along cable route on ichthiofauna. It has been shown in previous investigations that in the case of a water medium a longitudinal component of EMF is prevailing and can be characterized by longitudinal current density or longitudinal intensity. The intensity of a longitudinal field depends on the following major factors: design of the armour and sheath of underwater cable; mode of cable line operation; method of cable laying; magnitude of grounding resistance of the screen and sheath on coastal substations; conductivity of water medium. All these factors characterize a longitudinal field not only in a normal operational mode, but also at short circuits. In the present work, as well as a normal mode of operation, stationary modes, external (in system contiguous to CL) and internal (between conductor and sheath in CL) short circuits, are also considered. Even though there is not enough systematic data on the influence of exposure time of a electromagnetic field on ichthiofauna, analysis of the field characteristics at times of exposure, determined by relay protection, can help in deciding on appropriate future experiments