To improve the intelligent degree of traditional high-voltage handcart circuit breakers

the electronic transformer and the main unit of integrated protection device were integrated in the circuit breaker

and the methods for enhancing the electromagnetic compatibility of hardware system of the integrated protection device were adopted

as a result

a new 12 kV intelligent handcart circuit breaker with deep fusion of primary and secondary parts was developed. A testing program was designed to verify the working reliability of the intelligent equipment in running state

in which the rated current of 1 250 A and the simulated fault currents of respective 1.8 and 31.5 kA were applied to the primary loop. Testing result shows that this circuit breaker can correctly detect normal and fault current

the integrated protection device in the equipment can make right judgement and quickly send out the instruction of cutting off fault current

the circuit breaker can operate correctly after receiving the instruction and perform tripping operation to switch off the fault current.