Pacific service magazine . nductor the corona losswill be to 10 kw. per mile of idea of the narrow margin on whichwe are working can be had from a con-sideration of the fact that the loss increasesto 75 kw. per mile at 260 kv. The mechanism of this loss is not fullyunderstood but is being studied by somevery able men. 3—Voltage Control A third major transmission problem isthat of voltage control. It is hardly necessary to consider thefundamental praperties of an electric cir-cuit transmitting an alternating are all familiar with the fact that apart of the voltage appl
Pacific service magazine . nductor the corona losswill be to 10 kw. per mile of idea of the narrow margin on whichwe are working can be had from a con-sideration of the fact that the loss increasesto 75 kw. per mile at 260 kv. The mechanism of this loss is not fullyunderstood but is being studied by somevery able men. 3—Voltage Control A third major transmission problem isthat of voltage control. It is hardly necessary to consider thefundamental praperties of an electric cir-cuit transmitting an alternating are all familiar with the fact that apart of the voltage applied is consumed bythe circuit. The three basic voltages,which are the voltage applied, the voltageconsumed by the line and the voltage de-livered are related vectorially but not arith-metically. The vector relation of the voltage con-sumed by the line to the voltage impressed,depends upon the amount of current trans-mitted and on the power factor of thatcurrent. The difference between the im- Pacific Service Magazine 291. BIAGRAM OF VECTOR RELATIONS Fig. 3 pressed andi delivered voltage is thereforedependent on the amount and the powerfactor of the load. If the load is large andthe power factor is lagging as is usually thecase in commercial loads the impressed volt-age must be greater than the voltage de-livered. However, as the power factor of theload is brought up to unity the differencebetween impressed and delivered voltagebecomes less and if the power factor canbe made to lead a proper amount the im-pressed and delivered voltages may be equal. For example, consider the case of a 200mile 220 volt circuit. At 120,000 kw. loadat .8 lagging power factor the impressedvoltage would have to be 132 per cent ofthe delivered voltage, at power fac-tor 111 per cent and at 96 per cent leadingpower factor the impressed voltage wouldbe the same as the voltage delivered. {SeeFig. 3). Practically, the voltage of a long trans-mission system must remain steady at bothsending and recei
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