# HW3 - connected load through a transmission line having an...

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ECE 333 – Green Electric Energy Spring 2010 Homework 3 Due Date: Thursday February 11, 2010 Reading: Sections 6.1-6.5 in Chapter 6 of Masters Problem 1. A 345 kV three-phase line supplies 750 MVA at 0.8 PF lagging to a three-phase load which is delta connected. 1. Find the complex impedance per phase. 2. Find the magnitudes of the line and phase currents. 3. Compute real and reactive power per phase. 4. Compute the total complex power. Problem 2. A three-phase wye connected motor draws 40 kVA at 0.65 PF lagging from a 230 V (line-line) source. A wye-connected capacitor bank is connected across the motor terminals to improve the PF to 0.95 lagging. 1. FInd the kVAR rating of the capacitor bank. 2. FInd the line current before and after the capacitor are added. Problem 3. A three-phase power system consists of a wye-connected generator connected to a wye-
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Unformatted text preview: connected load through a transmission line having an impedance of Z line = 1 . 5 6 75 per phase. The load impedance is Z L = 20 6 30 per phase. The voltage at the load is 4.16 kV (line-to-line). Take phase a load voltage reference. 1. Draw the per phase equivalent circuit for phase a. 2. Compute I a , I b , I c , , and the voltages V an , V bn , V cn , V ab , V bc , V ca . 3. Compute the total complex power of load. 4. Compute the total complex power supplied by the generator. Problem 4. An industrial plant consists of several three-phase induction motors and draws 300 kW at 0.6 PF lagging from the substation bus. Find the kVAR rating of a capacitor bank to improve the PF to 0.9 lagging....
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## This note was uploaded on 03/04/2011 for the course ECE 333 taught by Professor Overby during the Spring '09 term at University of Illinois, Urbana Champaign.

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