Patent ID: 8830646

Claim:
A protection coordination system comprising: a first relay arranged on a first load line of a distribution power system; a second relay arranged on a second load line at a point further from a center of the distribution power system than the first load line, wherein a current at a start point of an instantaneous operation section of the first relay is greater than a current at a start point of an instantaneous operation section of the second relay; and a current limiter arranged on a line between the first and second relays and configured to limit a fault current generated on the second load line to within a predetermined scope, wherein the current limiter includes: a detecting unit configured to detect the fault current generated on the second load line and further configured to transmit an open signal to a switch; the switch configured to be opened by the open signal; and a current limit resistor connected in parallel with the switch and configured to reduce the fault current when the switch is opened.