Patent ID: 9599654
Date: 2017-03-21
CPC Classifications: G01R,H02H

Claim:
1. A high-speed fault current detection circuit, comprising: a primary current transformer configured to detect a current flowing through an electric power circuit in a grid to output a current detection signal; a pair of secondary current transformers connected to the primary current transformer to convert and provide the current detection signal provided by the primary current transformer into secondary conversion signals, respectively; a fault detection circuit section connected to any one output terminal of the one pair of secondary current transformers to determine whether or not a fault current occurs on the electric power circuit by comparing a current value represented by a secondary conversion signal outputted by either one of the one pair of secondary current transformers with a predetermined reference current value of said fault detection circuit section, and output a fault detection signal when determined that the fault current has occurred; a surge detection circuit section connected to the other output terminal of the one pair of secondary current transformers to determine whether or not a surge current occurs on the electric power circuit by comparing a current value represented by a secondary conversion signal outputted by the other one of the one pair of secondary current transformers with a predetermined reference current value of said surge detection circuit section, and output a surge detection signal when determined that the surge current has occurred; and a trip determination unit connected to output terminals of the fault detection circuit section and the surge detection circuit section to receive the fault detection signal and the surge detection signal, and generates a trip control signal when at least either one of the fault detection signal and the surge detection signal is received.