FIELD: electrical engineering. SUBSTANCE: procedure testing insulation resistance and protection of alive DC network against fault to ground in one point. Procedure is based on analysis of voltage difference with reference to ground measured at different time moments across poles of network while additional voltage source of special form is connected to them through additional resistors by bridge circuit and on test of current difference in branch of this source. Equivalent resistance of insulation with reference to ground is evaluated by obtained difference of measured values, is compared with permissible value and if it is less than permissible value then warning or controlling signal for disconnection of network or for its replacement is formed. At same time insulation resistance of each pole of network is determined by measured values, faulty element of network is found and information signal on damaged element is formed. Given procedure makes it possible to test insulation resistance of network under rated conditions continuously, to expose faults to ground in any point of protected network without insensitivity zones, to determine character and faulty points in emergency situations. EFFECT: increased speed and reliability of procedure. 3 cl, 4 dwg
