System for compensation of capacitive and active earth currents

摘要

A system for compensation of capacitive and active current components in a 3-phase a.c. mains network includes an induction unit 1 connected between an artificial neutral point 2 of the mains supply and earth. The induction unit 1 includes a work winding, two auxiliary windings and means for adjusting the inductance of the work winding. In the event that one phase of the network fails, a fault signal is passed from control-measurement means 5 to a control unit 4. The control unit generates control signals to control the inductance adjustment means so as to vary the inductance of the work coil to compensate the capacitive current component, and to control an impedance converter amplifier 3 which acts on the work winding via the auxiliary windings to compensate the active current component. Compensation of the current components is achieved by bringing the inductance of the induction unit to resonance with the mains capacitance. IMAGE