Over-voltage protection device includes discriminator detecting rate of voltage change to determine when earthing is required

摘要

The protection device (2) includes a discrimination device (4) which measures the rate of variation of the voltage on the network as a function of time. If this rate of change exceeds a preset value, the electric power line is earthed via a spark discharge device. The protection device (2) for a power distribution network (1) is intended to guard against transitory over-voltages. It includes a discrimination device (4) which is set up to measure the rate of variation of the voltage on the network as a function of time. If this rate of change exceeds a preset value, the electric power line is put into contact with the earth connection (3) via a conducting component (5). The conducting component may be a spark discharge device, mounted in series with the discrimination circuit. Alternatively the conducting component may be a varistance, or a thyristor may be used within the circuit.