Question

Numerical Example Power has to be carried over a distance of 200 km to feed a 75 MW unity power factor load. If the line is uncompensated, a. Determine and select the line voltage b. Select an appropriate conductor size c. Calculate Voltage Regulation d. Calculate line losses.

3 phase

like what

Answer 1

Giren data, Load power = 75mW wwņ 2 Assure stoor Load power factor, coso connected incompensated line Distance over which power to be cooord - 200km = 200X163 m. we have to find, a) pooper line voltage b) Appropriate conductor size. o voltage regulation d) Line losses, at a) selecting line Voltage: 75 MW can be transmitted to any of the following 34 transmission voltages but We should score about our ampacity Jequrements of cusdent carorand conducto voltages or can be, lloku 44oku, 765 kW ( In India). 220kV, 230kv,Stoon-

i) fou lokv, tamper cats = 75 xobco v yes 43V X Cesar V3x110x103 : 393.648 A Ampacity i) For 22oku, 75xiob 13x 220X103 = 196.824 A 90) for 240 kv, Ampacity=7sxiob 53x240x183 - 180.422 A 1 ius For 4uoku, i Ampacity= 758106 73x440 x103 = 98.411 A. IN For 765 kv, . Ampacits = 75x106 53 x 288X103 -56.6029 A I so, we have to think about how much I we could spend on line and how easy it Gill be to build line using bundle conductors

It is always suggested to transmit voltages at higher level which leads to reduction in the of conductor of the to for high voltages, cworent reaired is les losses also will get reduced ... Bosed on previous page analges, I could choose the voltage of 440 ku based on the length that we want to transmit even though 765k0 provides less ampacity. If we use 765 kv) voltages, e require Coorge transformers & other equipments which would increase cost of Supstem. i Esok is selecred line voltage.

6) conductor size: Based on the Cuorrent that the conducten has to bare of ambient temporation, size of & material conductor Let us consider Aleminim Conductor Ampersistys Clorrent density. x cooss sectioned arra ... cross sectional 1. . area = Ampacity Current density 3 98.411A 3.5 Alman » Coorent density for sale conductor -3.5Alm2 this Cross sectional = 28-1174 mm2 corea of almim i conductor size should be more than keeping in mind fault accwences. - Conductor size would be around = Somma -

c) voltage regulation. It tells us how voltage profile to is mount clining. It should be as lear as possible which implies good Voltage profile of voltage regulation - Sending and voltage 0 - Recieving endroltage se Praling end voltage - Vs - VR X100 Vs Vs-vrt This indicates voltage doop. voltage doop/phase = (covent/phase y bene - . ? Iphxren rezistima L = 98.400)x Repti Ryen = (P/en/km] X200km for alimpum conductor of sige Somme), the resistance per km (Pe, R/km = 0.530/km).

» R/ph= T R/pn= (0.53)x200 10bn I Asowy, voltage doop (phase = 68.40714(106) - | D421-S66 Yead of Regulations voltage 10431.566 Viphas y 2440x103yphas Luz 4.106 % . d) line losses crorre) = 3 (pp)? Rph 33(98.40)2C106) = 3679742-52 Plosses = 3.0798 MW Note: Given E is incompensated line, so, voltage doop would be more than oros calculated doop because we did not consider reactance drops Cas not provided in calculations so, voltage zsulation also will be greater than Callulate
Note:

Data regarding resistance of conductor collected from some ieee studies and it can be calculated by taking resistivity of aluminum conductor and length. We can calculate by placing it in the resistance formula as per ohms law. Thank you..