| 摘要 |
PURPOSE:To minimize the loss generated in a static inductive electric device main body and a cooling device, by deciding the number of pumps and fans of the cooling device in accordance with th load state of the static inductive electric device and the ambient temperature. CONSTITUTION:The load current is measured by a bushing type transformer 7 of a tank 1 containing a transformer enclosed into the insulated oil, and at the same time the ambient temperature is measured by a temperature sensor 8. These results of measurement are fed to detecting part A. A deciding part B decides whether the load current and the ambient temperature are different from each reference value. Based on this result of decision, an arithmetic part C sets a certain time section to the load obtained after an fluctuation and at the same time varies the number of cooling devices 3 under operation to each of the divided time sections to calculate the total loss and the rise of the winding tempeature. According to this result of calculation, a deciding part D selects the number of pumps 5 and fans 6 of the device 3 so that the total loss becomes minimum within the allowable value for the rise of the winding temperature and then operates the pump 5 and the fan 6 via an indicating part E. Thus the total loss can be controlled to the minimum level. |
