FIELD: open-arc short-circuit protection of metal clad switchgear cubicles . SUBSTANCE: device has two light conductors of different attenuation factors assembled into common cable , two photoelectric converters, electronic signal-processing unit, and n final elements, where n is number of cubicles under protection. Each light conductor is optically coupled on one end with input of its respective photoelectric converter; outputs of photoelectric converters are connected to respective inputs of electronic signal-processing unit. Each of its n outputs is connected to respective final element; attenuation factors of light conductors differ by Δα ≈ 2/L, where L is light conductor length. Electronic signal-processing unit is designed for implementing mathematical function x = 1/Δα•InI1/I2, where x is distance from arcing metal clad switchgear cubicle to photoelectric converters along light-conductor cables; I1,I2 are photoelectric output currents of photoelectric converters. EFFECT: enlarged length of metal clad switchgear internal section handled by protective device. 2 dwg
