EECE 471 Midterm, Fall 2005

S. KARARKT AMERICAN UNIVERSITY OF BEIRUT FALL 2005/2006 FACULTY OF ENGINEERING AND ARCHITECTURE MIDTERM FUNDAMENTALS OF POWER SYSTEMS ANALYSIS (EECE 471) CLOSED BOOK (90 MINUTES) NOVEMBER 14, 2005 PROGRAMMABLE CALCULATORS ARE NOT ALLOWED THIS QUESTION SHEET MUST BE RETURNED WITH THE ANSWER BOOKLET. NAME: ID#: 1. Answer the following questions in the space provided for each on this question sheet: a) Label the various components of the power station schematic shown in Fig.1 below and give it a specific caption next to the figure number. ~p pts au CiecurS Sh RCL Con bel Valve 7 ‘ (Rw Fumet | Turbin ; Chen etc te Tra nsin ssi Line Condenser Creek ing Cirarta how tower Pasinp Fig: ©, 0 - Live dS rtm Pow Plant b) What is the most efficient thermal power generation technology used throughout the world nowadays and what is its approximate efficiency? i] 7 ~ . . ia - & leonbined Coe & Dowta Plant. ¢ Plies enc 2 abint SO A c) Name two environmental problems associated with fossil-fuel power plants and indicate ways of mitigating them? Emission el Cache Wiawide auc Sul fin bx les. The First “a gften -houre ga> while Hy decanc\ RSSOCAD ted UAHA acid Tain. CO, Com be nem hyaoliy 20) ey plan hag wee rd SO, 502 effet Gud eduad ley desut Puri zahon of Fuck Ot lay Haws qorwnin § Aun mo oes fue EECE 471E MIDTERM - FALL 2005/ 2006 Page 2/5 d) Name a renewable energy technology that you believe is most likely to be used and explain the reasons? a . (eve xb/ Kw en Wind tvuinguy: tethneley ep na hunt and eConom Gud Can lee wed whin Availayle. Solar pnote vet tea bingy cestddl be waed aa io: 4 ty gy ig fm at ya a, WHR GUalee gat aly Gat a By mg C$2tore/ ew ). e) Why do we raise the voltage to transmit a given amount of power over a long distance? oo, 2 : ; Onn @ long disttun & Rw bagel and ASR ( Cossea) GAL ugh Fatu Woy XG wnducw d lay ADAG V din @ PNT (@um hy win fecha) ~ 2. It is required to design a transmission line of 200 mile length to supply a demand of 300 MW at 0.9 PF lagging considering one of two voltages 220 and 400 kV at a frequency of 50Hz with typical phase-to-phase spacing of 8 m and 12 m, respectively. Note that 1 kcmil= 0.507mm’ and 1 fi= 0.305 m. a) Considering that characteristic impedances of lines vary within a narrow range around 300Q, calculate the surge impedance loading (P/Ps,) at both voltage levels. Refer to Fig. 2 below and deduce the more economic voltage that would maintain a stability margin such that the phase angle from sending to receiving is smaller than or equal to 45°. b) From Table 1 shown below select the most appropriate conductor size at the selected voltage if the current density is not to exceed 2.5 A/mm‘ at the given load conditions and the prevailing 35°C ambient temperature. Consider using bundled conductors in your design and select the appropriate number of bundles in your conductor. c) Calculate the resistance, inductance and capacitance for the line design and determine its actual characteristic impedance and its surge impedance loading at the selected voltage level. d) Ifat minimum load conditions, the demand drops to about 40% of its peak value, estimate the voltage at the sending end under such conditions. Having reached so far in your design, are you still confident that you have made the correct voltage choice? Explain. Table 1: Main Properties of Selected ACSR Bare Wires Name Size Resistance | GMR (kemil) at 60Hz (ft) (Q/nile) Partridge 266.8 0.411 0.0217 Linnet 336.4 0.327 0.0244 Ibis 397.5 0.277 0.0265 Hawk 477.0 0.231 0.0290 Dove 556.5 0.198 0.0313 Grosbeak 636.0 0.173 0.0335 Drake 795.0 0.139 0.0375 | cc 4. 2. oO z= 3 aa ik USE) - x Re ay S727 30 Ss) NS - ~~ / a, of AUD KV Vs pl | J | fACY A an oe an | | Qufjply ni Habe! i Daw cat aay vy 79 Id Lt Wale | i am te as Vea Ly : but |G | Pb | | Re gh) Lisin b. Zi G L | Asad Nr) J LL =|! i ee | mt tt a | 99, Ld Lik /p 12 | | jfile | FOR ANSWER