Chapter 2: ThreePhase Circuits
21.
Three impedances of 4 + j3 are connected and tied to a threephase 208V power line. Find I , I L ,
P, Q, S, and the power factor of this load.
SOLUTION
IL
+
240 V
I
Z

Z = 3 + j4
Z
Z
Here, VL = V = 208 V , and Z =
Review of 3Phase AC
Circuits
EE 340
Y. Baghzouz
Advantages of 3Phase
Systems
Balanced 3Phase Systems
3Phase Voltage Source
Neutral Wire Sharing
Neutral Current
Phase and Line Voltages
Example of Phase and
Line Voltages
YConnected Load
Connected Load
Synchronous Generators II
Spring 2013
Generator Pf Curve
All generators are driven by a prime mover, such as a
steam, gas, water, wind turbines, diesel engines, etc.
Regardless the power source, most of prime movers tend to
slow down with increasing th
Fault Analysis
Spring 2013
Introduction
A fault in a circuit is any failure that
interferes with the normal system
operation.
Lighting strokes cause most faults on highvoltage transmission lines producing a
very high transient that greatly exceeds
the r
a
EE 340 Test 1  Take Home Problem (S.pointq)
Consider a 2.5 kVA, 60 Hz, 415V,3phase generator that is connected to a large
utility while serving a constant impedance load as shown below (perphase
circuit). The total real and reactive power $upplied I
Magnetic Circuits
EE 340
Spring 2013
Amperes Law
Ampre's circuital law, discovered by AndrMarie Ampre in 1826, relates the
integrated magnetic field around a closed
loop to the electric current passing through
the loop.
H.dl I
where H is the magnetic fie
EE 340 Transmission Lines
Spring 2013
Physical Characteristics Overhead lines
An overhead transmission line usually consists of three conductors or
bundles of conductors containing the three phases of the power
system.
In overhead transmission lines, th
EE 340
Power Transformers
Y. Baghzouz
Spring 2012
Preliminary considerations
A transformer is a device that converts one AC voltage to another AC
voltage at the same frequency. It consists of one or more coil(s) of wire
wrapped around a common ferromagnet
Synchronous Generators I
Spring 2013
Construction of synchronous machines
In a synchronous generator, a DC current is
applied to the rotor winding producing a rotor
magnetic field. The rotor is then turned by
external means producing a rotating magnetic
f
Review of AC Sinusoidal Circuits
Yahia Baghzouz
Spring 2013
Root Mean Square (rms) Value and Phasors
Impedance of linear elements
Instantaneous and Average Power, Power Factor
Pure Resistive Load
Pure Inductive Load
ResistiveInductive and resistivecapac
Induction Motors
EE 340
Spring 2013
Where does the power go?
The electric energy generated purchased by
consumers for different needs. This energy is
converted to different forms:
Lighting (indoor/outdoor CFL, incandescent,
LED, Halogen)
Heating (elect
Chapter 4: AC Machinery Fundamentals
41. Develop a table showing the speed of magnetic field rotation in ac machines of 2, 4, 6, 8, 10, 12, and 14 poles operating at frequencies of 50, 60, and 400 Hz. SOLUTION The equation relating the speed of magnetic
Chapter 3: Transformers
31.
The secondary winding of a transformer has a terminal voltage of v s (t ) = 282.8 sin 377t V . The turns
ratio of the transformer is 50:200 (a = 0.25). If the secondary current of the transformer is
i s (t ) = 7.07 sin ( 377t
pole 50Hz synehrouous generator whose prime mover has a noload speed of 1300 r."rrii1 and a fullload
speed of 1485 r"nJin. The loads supphedb}: the two generators consist M200 k's. at 0.83 PF lagging.
{a} Calculate the speed droops of generator 1 a
COURSE SYLLABUS
EE 340: Introduction to Electrical Power Engineering
Spring 2014
Instructor: Dr. Y. Baghzouz
Office Room # SEB2167
Tel. # 8950887
Fax # 8954075
Email address: Yahia.Baghzouz@.unlv.edu
Office Hours: 10:3012:30 TR and 10:0012:00 W
Requi
Power Flow Analysis
EE 340
Spring 2013
Introduction
A power flow study (loadflow study) is a steadystate
analysis whose target is to determine the voltages,
currents, and real and reactive power flows in a system
under a given load conditions.
The pur
Power System Representations:
VoltageCurrent Relations
EE 340
Spring 2013
Oneline diagram
(simple power system)
Machine ratings, impedances, consumed and/or supplied
powers are usually included in the diagrams
Perunit equivalent circuit
Real power sy
Chapter 9:
91.
Transmission Lines
Calculate the dc resistance in ohms per kilometer for an aluminum conductor with a 3 cm diameter.
SOLUTION The resistance per meter of aluminum conductor is given by Equation (92):
rDC =
A
=
r2
where = 2.83 108 m. Thi