FIELD: measurement.
SUBSTANCE: invention relates to electrical measuring equipment and relay protection of power supply systems and increases speed of measuring insulation resistance and protection. Method of controlling electrical resistance of insulation and protective disconnection of electrical equipment is based on measurement of leakage current from an auxiliary source of test voltage in form of a periodic sequence of pulses of the form
where U1, U2 are voltage constants, U1>U2, τ – time interval, 2T – period of test voltage pulses repetition, τ<T; leakage current measurement I1 in time interval T-T0<t≤T and leakage current I2 in interval 2T-T0<t≤2T, where T0 is voltage period of supply mains; T0<T-τ, by averaging of voltage drop on measuring resistor for period T0 of supply mains, calculating insulation resistance rins, comparing the obtained value with setting R1 and in successively determining n times the fact of reducing insulation resistance rins≤R1 disconnection of electrical equipment. In memory of controller two last results of measurement of leakage current are stored, and after each i-half of the measurement cycle, the insulation resistance is calculated by formula
where rt is the internal resistance of the source; i = 1, 2.
EFFECT: technical result consists in improvement of efficiency and reliability of monitoring insulation electrical resistance and protection of electrical network.
1 cl, 2 dwg
