410 ELECTRICAL ENGINEERING 



The relation between the voltages at the generating station and 

 receiving station is given by equation 



- jb) j] 



(r +jx) (g - jb + j - C J - j j c ( 



CG = 

 or 



Substituting the values obtained and neglecting the last term 

 E G = 60,OOOJ1 + (16 + 53.5 j) (0.00235 - 0.00123 j)\ 



= 60,000 (1.1034 + 0.1063 j), 

 and taking absolute values 



EG = 60,000 V(1.1034) 2 -f (0.1063) 2 = 66,210 volts. 



Thus to produce a voltage of 60,000 volts between lines at the 

 receiving station at full load a voltage of 66,210 volts is required 

 at the generating station. 



At no load the current / is zero and the admittance y is zero 

 and the voltage required at the generating station to produce 

 60,000 volts at the receiving station is 



E Q = 60,000 {1 + (16 + 53.5 j) (- 0.000231 j) j 

 = 60,000 (0.9877 + 0.003696 j) 



and in absolute values 



E G = 60,000 V(0.9877) 2 + (0.003696) 2 = 59,268 volts. 



At no load therefore the voltage at the receiving end of the line 

 is greater than that at the generating station. 



If full load is suddenly taken off the line the voltage at the re- 

 ceiving end will rise to a value 



E = 66,210 X 3 = 67,000 volts, 



7000 

 which is a rise of ^777^7: X 100 = 11.6 per cent. 



The generator voltage is here assumed to remain constant at 

 66,210 volts. 



The current per conductor at the generating station may be 

 found from equation 370 



lo = e[g - jb +jb c j 1 +t(j _ j&j 



