摘要 |
FIELD: electric engineering, namely, engineering of devices for relay protection of direct current networks from short circuit currents, possible use for protecting traction network of main railroads and industrial plants. ^ SUBSTANCE: device contains relay-differential bridge, formed by two parallel portions of buses having different cross-sections, passing inside a magnetic duct, on which calibrating coil is positioned, additionally provided are indicators of current derivative in form of isolated coils, outputs of each of which are connected to input of appropriate native high speed voltage relay of directional effect, forming a coincidence circuit, controllable thyristor, resistor and power source. ^ EFFECT: increased selectivity of devices protecting powering feeders of direct current traction network. ^ 2 dwg |