OPEN-PHASE DETECTION IN THREE-PHASE CIRCUIT TRANSFORMER AND DEVICE THEREFOR

摘要

PURPOSE:To implement open-phase detection without fail by detecting the temperature difference of windings constituting a delta network and by detecting that one phase is an open-phase. CONSTITUTION:The temperature of each winding of a three-phase circuit transformer 1 is detected by a temperature detector 2 and connected to an arithmetic section 5 of a device main body 4. After each temperature signal was amplified by an amplifier 6, it is inputted into a temperature difference arithmetic circuit 7. When the temperature difference between each phase winding is operated by the temperature difference arithmetic circuit 7 and one of these differences exceeds the set value of a temperature difference setter 9, an output is issued to an alarm circuit 10 by a comparison detection circuit 8.