METHOD AND DEVICE FOR LIMITING SHORT CIRCUIT CURRENT IN ELECTRIC NETWORKS Russian patent published in 2009 - IPC H02H9/02 

FIELD: electricity.

SUBSTANCE: when nominal current in electric network is exceeded, retention of short circuit current impulse is performed with current limiting device in two stages: at the first stage there performed is quick limitation of shock short circuit current during T₁ time with multiple-element resistance with active element based on hall effect with non-linear current-voltage characteristic, and at the second stage there maintained is nominal short circuit current during T₂ time with multiple-element resistance with active element with positive temperature coefficient of resistance with non-linear current-voltage characteristic. Both limitation stages are performed at voltage grading. Time T₁ is chosen not more than 2 ms, and time T₂ is chosen not less than 500 ms. The proposed device for limiting short circuit current in network includes two current limiting devices, the first one of which includes at least two shunted semi-conducting magnetoresistors, the active element of each of which is made in the form of Corbino disc from semi-conducting material of n-type A^IIIB^V, which are located inside solenoid, and the second current limiting device consists at least of two shunted resistors, the active element of each of which is made from material with positive coefficient of temperature resistance.

EFFECT: increasing switching speed, decreasing power loss in networks in nominal mode and forming the specified shape of short circuit current impulse.

3 cl, 4 dwg