lecture1

# lecture1 - EE 740 Professor Ali Keyhani Lecture #1...

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1 EE 740 Professor Ali Keyhani Lecture #1 Introduction to Power System Analysis and design

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2 Introduction: Name Office Hours Home work and grading policy Power system analysis and design - What does it mean? a) Estimate the loads The objective is to supply power to the b) Generation planning loads at acceptable frequency and c) Transmission line planning voltage. d) Electrical design Generator Loads Loads What are loads? a) Loads are specified as power consumption at the rated voltage. This course deals with : Computing load voltage given the specified load and generation. Design of power systems using specifications of conductor size, circuit breakers, and system needs.
3 Load Models: Inductive load - Impedance representation I L V L Z L Z L = R L + j ϖ L = R + jX L = / Z L / ∠θ / Z L / = R 2 + X L 2 θ = tan -1 (X L /R) Inductive load - Power representation I L = V L 0 / Z L ∠θ = I L - θ / I L / = / V L / / Z L / With the load voltage as the reference (ie V L = V L 0), the load current lags the voltage. V L 0 θ I L

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4 The complex power absorbed by the load is: S L = V L I* L = V L (I L - θ )* = V L I L cos θ + j V L I L sin θ S L = / V L // I L / ( in units of VA) P = V L I L cos θ (in Watts) Q = V L I L sin θ (in Vars) S = P + jQ (for an inductive load) θ = tan -1 (Q/P) cos θ = pf (power factor) Note: for inductive loads I L lags V L The load model is: V L Inductive load - Power model, pf lagging I L P + jQ
5 Load Models: Capacitve load - Impedance representation I L V L Z L Z L = R - jX c

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## This note was uploaded on 07/17/2008 for the course ECE 740 taught by Professor Keyhani during the Fall '07 term at Ohio State.

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lecture1 - EE 740 Professor Ali Keyhani Lecture #1...

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