| 摘要 |
Insulating oil in electric power transmission devices such as a transformer is filtered for removal of accumulated water and carbon particles. The filter and circulation pump are usually located in a separate cabinet external to the transformer with circulation conduits connecting the filter, the pump and the transformer. To prevent or minimize environmental contamination by leaks or ruptures in the oil circulation conduits, oil flow within the pump suction conduit is monitored independently of oil pressure within the pump discharge conduit. A flow rate or discharge pressure below a predetermined minimum operates motor control relays to terminate the pump drive motor operation and transmit appropriate alarms. Additionally, an accumulation of oil in the dry sump volume of a pump and filter housing also activates motor terminating relays and transmits an alarm. Simultaneous with disconnection of the pump drive source, the pump suction conduit is closed by a normally closed solenoid valve positioned in the line near the power transmission device.
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