Protective relay apparatus using the optical current sensor

摘要

Even a fault current in the protective relay device using an optical current sensor of two installed at the ends of the guard interval of the power system, obtained by superimposing the DC component, the detection of an internal fault as well, and an internal fault external accident and to provide a device which can be determined without being misread. Was placed in both ends of the guard interval 9 of the power system the light current sensor 2 and the second optical current sensor 1 of the first, not the optical fiber transmission line 3a to 3d is light current sensor light source 11, the first one, second I connected in series photocurrent sensor 2, the optical signal processing section 4b between the first and second optical signal processing portion 4a of the first. Movement amount calculation means 6a, the suppression quantity calculating means 6b, the operating rate calculating means 7 from the sum current signal from the optical signal processing unit 4b and the second differential current signal from the optical signal processing section 4a of the first operation amount, I ask inhibiting amount, the operation ratio. Operation even if the amount was more than the set value determination unit 8, the operation when the ratio is less than a predetermined value, to prevent unnecessary operation of the relay it is determined that an external fault.