DEVICE FOR DIFFERENTIAL-PHASE HIGH-FREQUENCY PROTECTION OF ELECTRIC POWER LINE Russian patent published in 1995 - IPC

FIELD: electrical engineering. SUBSTANCE: device includes input of constant voltage signal and measurement-logic unit provided with HF input of protection blocking, shutting-off output and output "HF start". Insertion of first time delay element for return, time delay element for operation, second time delay element for return and logic OR gate connected in series, linking of second input of logic OR gate and input of first time HF delay element for return to input of HF signal and of output of logic OR gate to input of protection blocking makes it possible to prevent unwarranted operation of protection with connection of uninjured disconnected phase of aerial power line and its transit locking. EFFECT: improved reliability of protection. 1 dwg