Industrial/Commercial Power
System Equipment
Cables
Transformers
Circuit breakers
Other protective devices: relays, fuses, etc.
protective devices: relays, fuses, etc.
Motors & motor controllers
Buses
Misc. equipment and components
4/15/2011
EE 640 _ Equi
Distribution Systems
or
Ref: IEEE Std. 241-1900
IEEE Std 241
4/15/2011
ECE 640 - Distribution Systems
1
Distribution Systems
Ref: IEEE Std. 241-1900
4/15/2011
ECE 640 - Distribution Systems
2
Distribution Systems
Ref: IEEE Std. 241-1900
4/15/2011
ECE 640
NEC 2011: Table
310.15(B)(16)
NEC 2011: Table 310.15(B)(2)(A)
NEC 2011: Table
310.15(B)(3)(a)
NEC 2011: Table
310.15(B)(17)
Feeder/branch circuit ampacity:
Iampacity =
NEC per conductor
ampacity from
Table 310-16
Number of
conductors
per phase
Derating fa
Ref: IEEE Std. 2411990, Fig. 101, p 448.
Natural thermal capability
Energy = powerdt
Power = I2R for resistive components
Thermal energy time constant > electrical cycle time
I2t = 10000
1000
time (seconds
100
10
1
0.1
1
10
100
current (amps)
1000
Time c
Industrial /
Commercial
Power Systems
Power Systems
Ref: IEEE Std.
241-1990, Fig.
101, p 448.
448
Analysis Concepts
Load characteristics
Voltage considerations
Apparatus
Wiring
Protective devices
Meters
Protection
Lighting
3/28/2011
EE 640 - Introduc
Metering
Rate structures may include 1 or more of
energy (kWhr) - variable charge; operating costs
demand (kW) - fixed charge; capital/equipment investment
power factor - penalty charge; increased losses & voltage
regulating equipment
voltage level
ECE 640 Quiz #1, Sp 11
3
Vth is simply the line-line voltage
Vth_a
69 10
3
divided by sqrt(3); generally the
angle is taken as the reference,
i.e., oo , but theorectly it can be
any value desired.
4
Vth_a 3.984 10
Vth_b
12.5 10
3
3
Vth_b 7.217 10
3
Vth_
ECE 640 homework #4, sp 2011
1. feeder 5 - 7 ; two 350 kcmil per phase; inuslation temp = 90 0 C; ambient = 300 C.
I350_90_30 350
from NEC table for copper condustors
there are two conductors per phase
No_cond 2
since 6 conductors (two per phase), derated
MA( z)
ECE 640 Homework #1, sp 2011
1.
pfb cos 25
pfa cos 25
100
500
pfd cos atan
100
500
pfe cos 30
pff cos 30
180
lag because P & Q both > 0
pfd 0.981
lead because P & Q both of different sign
pfe 0.866
lead because angle Z < 0
pff 0.866
180
la
ECE 640 Exam #1, sp 2011
1. efficient -NO; free from hazard -YES; adequate for future expansion -NO; NOT a design spec; NOT an
instruction manual
2. R*cos(I) - X*sin(I) = 0, therefore, sin(I)/cos(I) = R/X for a leading power factor; sin(I)/cos(I) =
tan(I)
Vo
Voltage Considerations
Co
Definitions
Voltage (of a circuit). (Ref: NEC) The greatest root-mean-square (rms) (effective)
diff
difference of potential between any two conductors of the circuit concerned.
th
Information note: Some systems, such as 3-phas
ECE640Quiz#4,sp/11
1. [5 points] Consider a copper conductor and an aluminum conductor,
both with identical physical characteristics, i.e., same length and same
crosssection. Assuming the same current flow in both conductors,
what is the relationship betw
ECE640Quiz#2a,b,c,sp/11
Name (print) _
Consider a 480 volt 3 system with the following system load
information for a 24 hour period of time:
(a)600kwhr
(b)500kwhr
(c)400kwhr
Pmax =30kW
Pmax =23kW
Pmax =21kW
Pconnected =35kW
Pconnected =30kW
Pconnected =28
EE 640
Homework #1
Due Monday 04 April 2011
The purpose of this homework is to review material from ECE 341 and some basic circuit analysis
that will be useful in this course.
1. Determine the power factor of each of the following 120 volt 1 loads (Note:
[62 43]
[33 22]
0.3 0.38
0.15 0.24
0.064 0.15
Fault location
fuse
CB-1
CB-2
CB-3
CB-4
CB-5
CB-6
CB-7
See fault Y
or N
Y
N
N
N
N
N
N
N
Y
Y
N
N
N
N
N
N
2
1
Y
Y
Y
N
N
N
N
N
3
2
1
Loc-1
Order of
operation
1
See fault Y
or N
Loc-2
Order of
operation
See fault
03/27/06
Cable related nomenclature for single line diagrams:
3 1/C 350 kcmil/phase and
neutral
total of 12 current carrying
conductors
2 1/C 500 kcmil/phase
total of 6 cu rrent carrying
conductors
1 3/ C 000
total of 3 cu rrent carrying
conductors
2 3/ C
