1
NWPUD Transmission Reinforcement
Planning
EE 456
Project 2 Final Report May 18th, 2015
Prepared by:
Yussuf Roble Bayu Halim Ki Hei Chan
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Table of Contents Executive Summary ...................................................................................................................................... 3
Load Growth ................................................................................................................................................. 4
Design Consideration .................................................................................................................................... 5
1st design .................................................................................................................................................. 5
2nd design................................................................................................................................................... 8
Technical Feasibility ............................................................................................................................... 10
Line Reactance Calculation .......................................................................................................................... 5
Load Growth only System Upgrade............................................................................................................ 10
Wind Farm only System Upgrade ............................................................................................................... 11
Cost Allocation ........................................................................................................................................... 12
Standards ..................................................................................................................................................... 13
Impact of Global Warming on our Design ..................................................... Error! Bookmark not defined.
Conclusion .................................................................................................................................................. 13
Reference .................................................................................................................................................... 13
Appendix ..................................................................................................................................................... 14
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Executive Summary
Figure 1
Recommended system upgrade
After analyzing different design options, we have decided to upgrade the system according to the
design shown in Figure 1. This design has a total construction cost of $37,230,142 with a total
annualized cost of $1,657,206/year. In comparison with other design upgrade options that we have
considered (different designs will be further analyzed in the later sections), this design is the
cheapest to build.
One of the most important factors in choosing the cheapest design in this project is minimizing the
number of poles and insulators that need to be rebuilt. The upgrade cost of any designs in this
project is highly dependent on the number of new poles and insulators that need to be installed
because the cost of poles and insulators are much more expensive compared to other equipment.
In our 1st design, the cost of poles and insulators is $25,520,000 while in our 2nd design, the cost
of poles and insulators is $32,870,000. Looking at just the cost of just poles and insulators, the 1st
design is much cheaper than the 2nd design. Therefore, the 1st design upgrade is the best alternative.
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Load Growth
Figure 2
Load growth with linear trend
Figure 3
Load growth with logarithmic trend
We predicted the load growth in seven years using two different trends: linear and logarithmic
(Figure 2 and Figure 3 respectively). The R2 value, which represents how close the date points
are to the trend line, of the linear trend is slightly higher than the R2 value of the logarithmic
trend. Therefore, the linear trend is slightly more accurate, and we predicted the load growth in
seven years to be approximately 338 MW.
220 224 222 235 234 248 258 263 275 275 283 291
y = 6.9231x - 13660R² = 0.9746
0
50
100
150
200
250
300
350
2002 2004 2006 2008 2010 2012 2014 2016
Pe
ak L
oad
(M
W)
Year
Peak Load growth (linear)
220 224 222 235 234 248 258 263 275 275 283 291
y = 13911ln(x) - 105552R² = 0.9745
0
50
100
150
200
250
300
350
2002 2004 2006 2008 2010 2012 2014 2016
Pe
ak L
oad
(M
W)
Year
Peak load growth (logarithmic)
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Line Reactance Calculation According to NESCode 233 regarding clearances between wires that ensure live-line worker safety,
115 kV conductors require 6 feet of spacing between a conductor and an insulator, which translates
to 12 feet spacing between conductors. Assuming spacing between conductors is a linear function
of voltage, a 69 kV conductors require approximately 6 feet of spacing.
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312 23 31
2*10 ln( ) H/ m
where
,
eq
s
eq
xy
s
DL
D
D D D D
D spacing betweenconductors
x y
D GMR of conductor
Equation 1
Line reactance formula [1]
Equation 1 above is used to determine the reactance of a conductor. The inductance value, L, gets
multiplied by the length of the conductor (in m). This represents the line inductance. This value
gets further multiplied by 2π*frequency to determine the line reactance.
Design Consideration
1st design
Our 1st design connects the Mustang Wind Farm to bus 4. Bus 4 is located in a 115 kV transmission area
and also it’s close to major load centers. On top of that, the 115 kV transmission line conductors
have higher rating which enables them to handle the load growth and the addition of the wind farm.
Furthermore, bus 4 is the only bus that requires the least right of way compared to all other 115
kV buses. Alternatively, we could have connected to bus 28 which is closer to wind farm in terms
of right of way, but it overloads all lines in the 69 kV area.
As mentioned earlier, through the design priority and constraint analysis our group found it’s
beneficial to connect the Mustang Wind Farm to bus 4. We based our analysis on factors like
minimum right of way, generator outage, testing for four different cases, conductor upgrade, be
able to reuse poles and insulators, proximity to major load centers and we concluded that
connecting the Mustang Wind Farm to bus 4 will have the minimum cost compared to all the other
available options.
Even though this design calls for 8 circuit breakers, 2 transformers, 11 miles 50 foot right of way,
64.5 miles of conductors upgrade, 43 miles of new conductors, and 1179 new poles and insulators
it will roughly cost $7M less than Design 2. If cost is the primary deciding factor for NWPUD,
then this design is the best and our team highly recommends it.
Figure 4 below shows the system diagram from PowerViz. The two parallel red conductors on the
left side of the figure 1 are from the wind farm while the other two red lines are two new conductors
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added to the system. The orange lines call for an upgrade of conductors, poles, and insulators
whereas the blue lines requires conductor upgrade but it will reuse the original poles and insulators.
Figure 4
1st design system diagram
Figure 5
1st design system upgrade
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Line number
From Bus to
Bus Poles and insulator
Size
( Kcmils)
Length of conductor
(miles)
Line 6 2 to 5 single, 115 KV 636 20
Line 7 2 to 6 no replacement needed 266.8 20
Line 8 4 to 6 Double, 115 kV
397.5 10.5
New Line 4 to 6 336.4 10.5
Line 9 5 to 7 single, 115 KV 795 3.2
Line 10 7 to 6 single, 115 KV 874.5 2.88
Line 11 6 to 8 Double, 115 KV 4/0.
11.2
New Line 6 to 8 11.2
From wind farm WF to bus 4 Double, 115 KV 477 11
Table 1
Line reinforcement on 1st design
Figure 5 and Table 1 highlight the upgrade that is required for the 1st design. This design requires
upgrade of 64.5 miles of conductors and addition of 43 miles of new conductors. It also calls for
updating all the poles and insulators that their conductor is upgraded except line 7 where the new
conductor weight is not 30% more than the original conductor weight. There is an addition of two
new lines for the Wind farm and also two new lines to reroute power to another bus. Figure 5 and
Table 1 are color coded to show conductors’ sizes, conductor’s length, and poles and insulators
replacement on a particular line.
Table 2
1st design cost summary
Design one alternative is substantially less expensive than design 2 alternative. This is due to the
cost of right of way and the number of lines requiring conductor upgrade which also effects how
many poles and insulators that have to be purchased. On top of that, a transformer and 2 other lines
Item quantity Capital Cost ($) Anualized Cost ($)
Right of Way 11 miles, 50 foot $2,667,500 $115,402
Conductor 107.5 miles $2,898,642 $125,402
Circuit Breakers 8 $144,000 $6,229.80
Transformers 2 $6,000,000 $306,116
Poles and Insulators 994 $25,520,000 $1,104,056
TOTAL COST $37,230,142 $1,657,206
TOTAL COST
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were overloading before adding a line between bus 4 to bus 6 and this significantly reduced the
cost of design one.
Note: Voltage profiles of different scenarios of the 1st design can be found in the appendix (Figure
9-Figure 12) and the cost breakdown of the 1st design can also be found in the appendix (Table 8-
Table 11).
2nd design
Our second design use three transmission conductor lines connected the Mustang Wind Farm. A
parallel lines connected to bus14 and a line connected to bus 27. Although using three conductors
need more material costs and right of way cost, we found this design can reduce too many lines
overload. Also, bus 14 and bus 27 is relatively close to the Wind Farm, and they both are 69KV.
Therefore, we try this design and use it for comparison.
In order to bear the load growth, N-0 and N-1 contingency stability study, we decided to add some
parallel conductor lines with parts of original lines which can decrease their total impedance and
reduce too much current flowing to the other parts and cause overvoltage.
Figure 6
2nd design system upgrade
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Line number
From Bus to
Bus
Poles and
insulator
Size
( Kcmils)
Length of conductor
(miles)
Line 6 2 to 5 single, 115 KV 477 20
Line 8 4 to 6 single, 115 KV 266.8 10.5
Line 11 6 to 8 double, 115 kV
397.5 11.2
New Line 6 to 8 397.5 11.2
Line 15 12 to 14 Single, 115 KV 266.8 6.4
Line 18 14 to 15 single, 115 KV 266.8 3.5
From wind
farm WF to bus 14 Double, 69 KV 666.6
7.6
From wind
farm WF to bus 14
7.6
From wind
farm WF to bus 27 Single, 69 KV
336.4
12.4
Table 3
Line reinforcement on 2nd design
Figure 6 above shows where the nine lines are added and Table 3 indicates the details of these
lines we choose. Figure 6 and Table 3 are color coded to show conductors’ sizes, conductor’s
length, and poles and insulators replacement on a particular line.
Material Capital Cost Annualized Cost
Total cost for 3-phase conductor $ 1,973,712 $ 85,387
Total cost for transformer $ 6,000,000 $ 306,116
Total cost for eight circuit breaker $ 132,000 $ 5,711
Price of poles $ 32,870,000 $ 1,422,034
Right of Way $ 2,910,000 $ 125,894
Total Cost $43,885,712 $1,889,587 Table 4
2nd design cost summary
This alternative requires a little bit more materials for constructions. In addition to the cost of
conductors, we need: 20 miles, 30 feet right of way, six 69kV circuit breakers, two 115kV circuit
breaker, and two 60MVA step up transformer on the wind farm.
Note: Voltage profiles of different scenarios of the 1st design can be found in the appendix (Figure
13-Figure 16) and the cost breakdown of the 1st design can also be found in the appendix (Table
12-Table 15)
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Technical Feasibility
The 1st design requires the acquisition of 11 miles of right-of-way, and must cross 2 buses and
three transmission lines depending on final line routing. Our team has also increased the cost
allocation of poles in order to accommodate the larger poles necessary for an 115kV line to cross
above a 69kV line between bus 15 and bus 12. There are significant overloads on the conductors
close to bus 4 due to the addition of the wind farm and load growth, this entire design must be
implemented by 2017.
Load Growth only System Upgrade
Figure 7
Load growth only system upgrade
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Line number From Bus to Bus Poles and insulator Size (kcmils) Length of conductor(miles)
Line 6 2 to 5 single, 115 KV 397.5 20
Line 7 2 to 6 no replacement needed 300 20
Line 8 4 to 6 no replacement needed 397.5 10.5
Line 9 5 to 7 single, 115 KV 477 3.2
Line 10 6 to 7 no replacement needed 397.5 2.88
Line 11 6 to 8 single, 115 KV 300 11.2
Line 38 8 to 28 single, 115 KV 336.4 20.8
Line 39 6 to 28 single, 115 KV 266.8 20.8
Table 5
Line reinforcement on load growth only system upgrade
The total cost for load growth only system upgrade is $28,539,248 with an annualized cost of
$1,234,675. The upgrade includes replacing some of the poles and insulators and reinforcing
conductors. Figure 7 and Table 5 show the lines that require reinforcement and poles and insulators
that need to replace with its corresponding length and distances. Figure 7 and Table 5 are color
coded to show conductors’ sizes, conductor’s length, and poles and insulators replacement on a
particular line.
Wind Farm only System Upgrade
Figure 8
Wind farm only system upgrade
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Line number From Bus to Bus Poles and insulator Size (kcmils) Length of conductor(miles
Line 6 2 to 5 single, 115 kV 605 20
Line 7 2 to 6 no replacement needed 300 20
Line 9 5 to 7 single, 115 kV 605 3.2
Line 10 6 to 7 single, 115 kV 795 2.88
Line 11 6 to 8 single, 115 kV 300 11.2
Line 31 24 to 25 no replacement needed 226.8 1.6
Line 38 8 to 28 single, 115 kV 266.8 20.8
From wind farm WF to bus 4 double, 115 kV 500 11
Table 6
Line changes on wind farm only system upgrade
The total cost for load growth only system upgrade is $36,213,875 with an annualized cost of
$1,563,210. The upgrade includes replacing some of the poles and insulators, reinforcing
conductors, and installing new lines to provide connection from the wind farm to bus 4. Figure 8
and Table 6 show the lines that require reinforcement and poles and insulators that need to replace
with its corresponding length and distances. Figure 8 and Table 6 are also color coded to show
conductors’ sizes, conductor’s length, and poles and insulators replacement on a particular line.
The wind farm only system upgrade requires an 11 miles, 50 feet right of way which costs
approximately $2,667,500. In addition, four 115 kV circuit breakers and two 60 MVA step up
transformer need to be purchased to complete the connection from the wind farm to bus 4.
Cost Allocation The cost allocation between the wind farm and the rate payers is governed by Equation 2 below.
wind farm only
windfarm combined
wind farm only load growth only
ratepayers combined windfarm
CC C
C C
C C C
Equation 2
cost allocation formula
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Using the above formula, the cost allocation is determined as such
1st design wind farm pays $20,821,534 (55.9%)
rate payers pay $16,408,788 (44.1%)
2nd design wind farm pays $24,543,553 (55.9%)
rate payers pay $19,342,159 (44.1%) Table 7
cost allocation summary
Standards
Conclusion
Reference [1]J. Glover, M. Sarma and T. Overbye, Power system analysis and design, 5th ed. Stamford: Cengage
Learning, 2010.
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Appendix
Figure 9
1st design n-1 contingency results during full load, full wind
Figure 10
1st design n-1 contingency results during light load, full wind
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Figure 11
1st design n-1 contingency results during light load, light wind
Figure 12
1st design n-1 contingency results during full load, light wind
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Table 8
1st design conductor cost breakdown
Table 9
1st design right of way cost
Table 10
1st design Poles and insulators cost breakdown
Item Quantity Voltage/MVA Bus Cost ($)
Circuit breaker 4 115 kV WF to bus 4 $72,000
Circuit breaker 2 115 kV Bus 4 to 6 $36,000
Circuit breaker 2 115 kV Bus 6 to 8 $36,000
Transformer 1 60 MVA WF to bus 4 3000000
Transformer 1 60 MVA WF to bus 4 3000000
Total cost $6,144,000 Table 11
1st design equipment cost breakdown
Line # From bus to bus New Cond. Size (Kcmils) Distance (miles) lbs/Mile Tot lbs of Cond.
Line 6 bus 2 bus 5 874.5 19 5940 112860
Line 7 bus 2 bus 6 300 19 2178 41382
Line 8 bus 4 bus 6 636 10.5 5213 54736.5
Line 9 bus 5 bus 7 900 3 6112 18336
Line 10 bus 7 bus 6 900 2.5 6112 15280
Line 11 bus 6 bus 8 636 10.5 5213 54736.5
WF WF bus 4 477 11 3462 38082
WF WF bus 4 477 11 3462 38082
NL46 bus 4 bus 6 397.5 10.5 2885 30292.5
NL68 bus 6 bus 8 336.4 10.5 2442 25641
Total cond. in lbs 429428.5
3 phase cond. lbs 1288285.5
Cost of cond. in $ $2,898,642.38
Line number From bus To bus Line voltage Distance (miles) Cost ($)
WF Lines WF 4 115 KV 11 $2,667,500
Right of way
Lines Single or double Distance in feet Span in (ft) # of poles Cost ($)
Line 6 Single, 115 KV 100320 300 334.4 6688000
Line 8 Double, 115 KV 55440 300 184.8 5544000
Line 9 Single, 115 KV 15840 300 52.8 1056000
Line 10 Single, 115 KV 13200 300 44 880000
Line 11 Double, 115 KV 55440 300 184.8 5544000
From WF to Bus 4 Double, 115 KV 58080 300 193.6 5808000
Total cost $25,520,000
POLES AND INSULTORS
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Figure 13 2nd design n-1 contingency results during full load, full wind
Figure 14 2nd design n-1 contingency results during light load, full wind
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Figure 15 2nd design n-1 contingency results during light load, light wind
Figure 16 2nd design n-1 contingency results during full load, light wind
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Line number From Bus to Bus Distance (miles) Size ( kcmils) Total pounds
6 2 to 5 20.9 477 86187
8 4 to 6 9.8 266.8 17692
11 6 to 8 10.9 397.5 71498
New line 6 to 8 10.9 397.5
15 12 to 14 6.4 266.8 11467
18 14 to 15 3.45 266.8 6225
0 WF to bus 14 7.6 666.6 6914
43 WF to bus 14 7.6 666.6
44 WF to bus 27 12.4 336.4 30192
Total cond. In lbs 230175
3 phase cond. In lbs 690525
Total cost of cond. $1,973,712 Table 12
2nd design conductor cost breakdown
Line number From Bus to Bus Distance (miles) Feet Cost
0, 43 WF to bus 14 7.6 30 $ 1,105,800
44 WF to bus 27 12.4 30 $ 1,804,200 Table 13
2nd design right of way cost
Line number From Bus to Bus Distance (miles) Voltage (KV) # poles Cost
45 2 to 5 20.9 115 368 (double) $ 11040K
49 4 to 6 9.8 115 173 (double) $5190K
46 6 to 8 10.9 115 192 (double) $5760K
50 6 to 8 10.9 115
47 12 to 14 6.4 69 112 (double) $2688K
48 14 to 15 3.45 69 61 (double) $1464K
0 WF to bus 14 7.6 69 135 (double) $3240K
43 WF to bus 14 7.6 69
44 WF to bus 27 12.4 69 218 $3488K
Total cost $32,870,000 Table 14
2nd design cost poles and insulators cost breakdown
Item Quantity Voltage(MVA) Bus Cost
Circuit Breaker 6 69KV WF to 14
WF to 27
$ 96,000
Circuit Breaker 2 115KV Bus 6 to 8 $ 36,000
Transformer 2 60MVA WF to14
WF to 27
$ 6,000,000
Total cost $6,132,000 Table 15
2nd design equipment cost breakdown
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Figure 17
Load growth only power flow results during normal condition
Figure 18
Load growth only n-1 contingency results during normal condition
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Figure 19
Load growth only power flow results during light load
Figure 20
Load growth only n-1 contingency results during light load
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Figure 21
Load growth only power flow results when Claytor is out
Figure 22
Load growth only n-1 contingency results when Claytor is out
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Figure 23
Load growth only power flow results when one of the generating units in Glenlyn is out
Figure 24
Load growth only n-1 contingency results when one of the generating units in Glenlyn is out
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Figure 25
Wind farm only power flow results during normal condition
Figure 26
Wind farm only n-1 contingency results during normal condition
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Figure 27
Wind farm only power flow results during light load, full wind
Figure 28
Wind farm only n-1 contingency results during light load, full wind
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Figure 29
Wind farm only power flow results during full load, light wind
Figure 30
Wind farm only n-1 contingency results during full load, light wind
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Figure 31
Wind farm only power flow results when Claytor is out (assuming full wind)
Figure 32
Wind farm only n-1 contingency results when Claytor is out (assuming full wind)
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Figure 33
Wind farm only power flow results when one of the generating units in Glenlyn is out (assuming full wind)
Figure 34
Wind farm only n-1 contingency results when one of the generating units in Glenlyn is out (assuming full wind)
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