621.319 accelerated aging amplitude of pulses of partial discharges cables based on twisted pairs for shipbuilding cooling bath length cooling mode correlation coefficient discrete resistive equivalent circuit method glass-mica paper tape halogen-free composition hygroscopic moistening irradiation coefficient location of the defect mechanical and electrical characteristics nodal potentials method partial capacitance partial discharges polyethylene insulation radiation modification service life system of linear algebraic equations tangent of the dielectric loss angle technological defects thermal aging thermal equivalent circuit transient mode voltage of the start of partial discharges амплитуда импульсов частичных разрядов безгалогенная композиция гигроскопическое увлажнение