| 摘要 |
FIELD: electrical engineering. ^ SUBSTANCE: invention relates to relay protection engineering, namely, to backup overcurrent protection of transformer with Y/Y winding connection. For this purpose, protection device contains current-to-voltage converters 1, 2 and 3 connected to A, B and C phases of current transformers on the side of high voltage in the protected transformer, rectifiers 1, 2 and 3, maxi-selector, threshold circuit, reference voltage source, time relay and intermediate relay. In addition, the following items are introduced: subtracter 1, 2 and 3, adder 1, 2 and 3, rectifier 4, 5, and 6, dividers 1, 2 and 3 and amplifier. ^ EFFECT: improved sensibility of backup overcurrent protection of transformer with Y/Y winding connection. ^ 1 dwg |
