Jeffcott — Electrical Design of A.C. High Tension Transmission Lines. 87 



vil = 200 (-000794 + i x -00189) = -159 + i x -378. 



cosh lid = cosh •159 cos -378 + isinh -159 x sin -378. 

 cosh -159 = 1 + -01265 + -000027 = 1-01268. 

 sinh-159 = -159 + -00067 + -0000008 = -15967. 



cos -378 = -9294. 



sin -378 = -3691. 



coshw/ = 1-01268 X -9294 + i x -15967 x -3691 = -941 + i x -059. 



sinh ml = -16967 x -9294 + i x l-012fi8 x -3691 = -1482 + i x -374. 

 wsinhm^ = (448 - i x 188)(-1482 + i x -374) = 136-8 + i x 139-6. 



sinh ml -1482 + * x -374 , ,^ „^ . o„^, ,„ 



^r- = -44831TT8-8- = (- l^-O^ + ' ^ 826) x 10-^ 



(4) Calculation of electrical quantities. 



V^ = ^°-~r^ = 76,000, at cos ^ = -85, = 64,600 + i x 40,000. 

 v o 



P^ = ?^0 = 2,750 kw. 



^ 2,750,000 - ^., 



^' = 7M00VT5 = ^2'" ^'^P^- 



Fj = Fscoshw)^ + viCasinh^rt^. 

 Vo cosh ml = (64,600 + / x 40,000) (-941 4 i x -059) = 58,440 + i x 41,450. 

 C2?isinhmi = 42-5 (136-8 + i x 139-6) = 5,810 + i x 5,930. 



.-. Fj = 64,250 + i x 47,380 = 79,900 volts to neutral at sending end. 



Ci = Ci cosh ml + — -^ sinh ml. 

 11 



ft cosh m/ = 42-5 (-941 + i x -059) = 40 + t x 2-51. 

 Y 

 'sinh Ml/ = (64,600 + i x 40,000) (- 16-07 + i x 826) x 10"^ 



= - 34-08 + i X 52-76. 

 C^ = 5-92 + t X 55-27 = 55 amps, per phase at sending end. 

 Pj = 64,250 X 5-92 + 47,380 x 55-27 = 380,000 + 2,620,000 = 3,000 kw. 

 2,750 



n 



'I = 



3,000 



•917. 



64,25 + i X 47,380 ^i .,.. ^ . ,..,.. 

 ^^ = "94rTT^-059 = ^^''^^^ ^ ' " ^^'8'^^- 



"' V64,( 



iOO' + 45,800- 



600- + 40,000-2 



(5) Determination of corona loss. 



7 = -83 for 7/12 cable. 



S = 1-02. 



Vc = 123,400 X -83 X 1-02 x -156 x 2-89 = 47,000. 



50 x 200 

 Q = 5-53 X X (79,900 - 47,000)' x 10"^ = 2,120 kw. 



aOIENT. PKOC. R.D.S., VOL. XVII, NO. 9. 



