Case Study on Increasing the Transport Capacity
of 220 kv d.c. OHL Iernut-Baia Mare by Reconductoring,
using LM Technologies
Dr. Ilie ARDELEAN 1
Marius OLTEAN 2, Dr. George FLOREA 3, Elena MATEESCU 4, Daniel MĂRGINEAN
Prof. dr. Ştefan KILYENI 5, As. dr. Constantin BĂRBULESCU 5
4
Romanian Power Grid Company C.N.T.E.E. “Transelectrica” SA, Timişoara Subsidiary, Romania
C.N.T.E.E. “Transelectrica” SA SMART SA, Sibiu Branch, 3 Tehnorob SRL, Bucharest, 4 Fichtner, Romania,
5 “Politehnica” University of Timişoara, Faculty of Electrical and Power Engineering, Power Systems Department
1
2
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Content
1. Introduction
2. OHL identification in the West part of NPG, in which the reconductoring has
maximum efficiency
3. Adopted reconductoring solutions and types of conductors used
4. LM technologies proposed for implementation
5. Evaluation of economical efficiency of reconductoring
6. Conclusions
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1. Introduction
 New OHL - difficulties in obtaining land for clearway
 Arguments for increased transport capacity of existing OHL
- increasing power consumption
- connection new renewable sources (wind) to NPG
- network congestions
 Solutions to increase transmission capacity of the OHL - uprating:
- increasing the current value
- increasing the voltage value
- increasing both values of current and voltage
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1. Introduction
Summary of key methods and instruments used to increase OHL capacity - Table 1
Table 1
4/27
2. OHL identification in the West part of NPG, in which
the reconductoring has maximum efficiency
 Software tool is designed in Matlab
environment enjoying the entire
characteristics specific to Microsoft
Windows operating systems, having a user
friendly interface
 The flowchart is presented in Fig. 1
Fig. 1
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2. OHL identification in the West part of NPG, in which
the reconductoring has maximum efficiency
 Report generated by the software
application – Fig. 2
 For the case of each congested
branch, two kind of information are
available:
- the sample containing the
congested branch
- the scenarios leading to the
issues pointed-out
Fig. 2
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2. OHL identification in the West part of NPG, in which
the reconductoring has maximum efficiency
-5 7 .2 M VR
GADALIN
28037
UNGHE.A
28459
84
XRO_ M U1 1
IERNUT 5
29159
193 MW
1 1 8 M VR
ROS IORI
28039
ORAD II
28839
ORADEA
28096
5 0 .6 M W
-0 .1 M VR
7 8 .9 M W
1 8 .2 M VR
7 1 .0 M W
1 2 .5 M VR
1 6 .1 M W
-0 .7 M VR
5 9 .2 M W
1 2 .9 M VR
1
2 6 .7 M W
3 .9 M VR
28069
ARAD
28485
BAIA M A
2 0 M VR
LOTRU
28040
LOTRU 1
29232
29169
M INTIA 5
1
29233
LOTRU 2
0 .0 M W
0 .0 M VR
2
S IBIU
28100
S IBIU
28034
1
2 2 8 .4 M W
7 3 .5 M VR
28538
S IBIU S
2 7 7 .1 M W
-1 4 .9 M VR
2
2
29167
M INTIA 1
28792
PES TIS
28070
S ACALAZ
5 1 .7 M W
7 .7 M VR
28068
M INTIA B
28003
M INTIA
28067
M INTIA A
5 5 .8 M W
9 .5 M VR
7 2 .3 M W
-1 2 .4 M VR
6 1 .6 M W
-1 6 .6 M VR
28756
S ACALAZ
28066
PES TIS
-1 0 0 .6 M VR
29162
RETEZAT1
2
29262
M INTIA 6
1
6 .2 M W
-1 .4 M VR
M INTIA
28787
28071
TIM IS
29260
M INTIA
3
HAJD OT.
28065
2 1 .7 M VR 2 1 .9 M VR
1 5 0 .8 M W 1 5 7 .6 M W
28914
R.M ARE
1
4 7 .4 M W
7 .2 M VR
HAS DAT
28795
4 5 .4 M W
-8 .0 M VR
BARU M
28064
PAROS EN
28063
1 .2 M W
0 .6 M VR
3 9 .8 M W
8 M VR
2
28746
TIM IS A
28747
TIM IS B
7 9 .2 M W
9 .1 M VR
70 MW
6 M VR
1 7 .8 M W
9 .9 M VR
BARU M A
28800
8 4 .8 M W
4 6 .9 M VR
2 5 .7 M W
-4 .4 M VR
4 3 .8 M W
3 .6 M VR
1 8 .6 M W
6 .1 M VR
28808
PAROS
7 5 .0 M W
1 0 .8 M VR
EN
2
28737
IAZ B
28736
IAZ A
6 3 .6 M W
7 .1 M VR
28062
5 3 .8 M W TG.JIU
6 5 .5 M VR
26 MW
1 9 .8 M VR
28054
IAZ 1
28694
URECHES T
28053
IAZ 2
2 3 .8 M W
1 0 .9 M VR
9 1 .2 M W
4 1 .6 M VR
28052
RES ITA
28045
URECHES I
1 0 .1 M W
1 .5 M VR
0 MW
0 M VR
29119
ROVIN 5
28729
RES ITA A
29120
ROVIN 6
2 2 9 .6 M W
1 0 9 M VR
29121
ROVIN 3
2 5 8 .3 M W
4 7 .2 M VR
29238
ROVIN 4
0 MW
0 M VR
29455
ROVIN 7
28002
URECHES I
6 6 .0 M W 3 9 .3 M W
0 .4 M VR 2 1 .3 M VR
3 .0 M VR
2 1 .9 M W
1 8 .7 M W
-1 1 .1 M VR
7 .4 M W
3 .4 M VR
2
28719
TR.S .ES
29102
CETATE
1 1 1 .5 M W
-7 M VR
28048
TR.S EV
6 2 9 .7 M W
-6 6 .4 M VR
28709
CALAFAT
8 1 .8 M W
-2 7 M VR
29250
P.D.F.6
269 MW
1 0 9 M VR
57 MW
1 5 .2 M VR
28730
RES ITA B
1
29189
P.D.F 1
5 0 .1 M W
1 9 .1 M VR
8 9 .2 M W
-1 .4 M VR
4 8 .9 M W
1 8 .7 M VR
0 MW
-0 .9 M VR
9 8 .2 M W
-1 1 .4 M VR
1 5 0 .0 M W
2 2 .1 M VR
1 5 .9 M W
2 .7 M VR
1 1 1 .5 M W
-7 M VR
S IBIU S B
28537
LOTRU
28562
9 9 .0 M W
-1 1 .3 M VR
1 .0 M W
1 6 .9 M VR
28775
ARAD B
1
1
5 9 .2 M W
5 7 .1 M W
1 2 .3 M VR
1 2 3 .2 M W
5 .0 M VR
28460
UNGHE.B
CUPT.C.T
28088
5 2 .1 M W
1 4 .3 M VR
28008
ARAD
 The case study is carried-out for the West
and South-West side of the Romanian
Power System – Fig. 3
 It has 88 buses and 107 branches
 The power system is operated by the
Romanian Power Grid Company
Transelectrica, Timisoara Subsidiary and
partially by Craiova and Cluj-Napoca
subsidiaries.
VETIS
28095
2
28774
ARAD A
2 5 .5 M W
4 .7 M VR
1 1 3 .8 M W
0 .6 M VR
VETIS
28491
UNGHENI
28086
IERNUT
28036
85%
8 2 .5 M W
-3 .2 M VR
8 5 .1 M W
2 1 .1 M VR
ROS IORI
28094
BAIA M .
28093
0 .5 M W
0 .0 M VR
8 7 .2 M W
1 6 .5 M VR
-1 7 9 .2 M VR
IERNUT
28524
1 7 .5 M W
-1 1 .7 M VR
BAIA M A3
28484
75
XS A_ AR1 1
CLUJ E
28038
CLUJ ES
28509
-9 6 .6 M VR
2 1 9 .8 M W
-6 0 M VR
193 MW
1 1 1 M VR
IERNUT
28087
86%
IERNUT 6
29160
28049
TR.S EV
1 4 .8 M W
-1 2 M VR
28050
CETATE1
28051
CALAFAT
28047
P.D.F.A
28046
P.D.F.B
1 1 1 .5 M W
8 .1 M VR
1 1 1 .5 M W
8 .1 M VR
2
29191
P.D.F 3
29192
P.D.F 4
1 1 1 .5 M W
-7 M VR
29190
P.D.F 2
29193
P.D.F 5
1
1 1 1 .5 M W
-7 M VR
28004
P.D.FIE
Fig. 3
3 2 7 .9 M W
-2 2 .3 M VR
85
XPF_ DJ1 1
6 2 .6 M W
2 2 .8 M VR
7/27
2. OHL identification in the West part of NPG, in which
the reconductoring has maximum efficiency
 The analyses have been performed for 1000 samples, each sample representing an
individual operating condition. Based on the analyses the following OHLs have been
selected:
- 220 kV OHL Iernut-Baia Mare;
- 220 kV OHL Portile de Fier-Resita.
 The beginning of the works at 400 kV corridor Portile de Fier-Resita-Timisoara-Arad
and the tie-line with the Serbian power system (Resita-Pancevo) represent a case in
point
 Iernut-Baia Mare 220 kV OHL has been selected having the maximum
reconductoring efficiency
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3. Adopted reconductoring solutions and types of
conductors used
Structural characteristics of the selected OHL are:
• putting into operation 1969
• total length 162.4 km
• no.towers 480 pcs. (of which: normal suspension 387 pcs., special suspension 15
pcs., tension 78 pcs.)
• towers names type SNY, SSY, ICNY, INY, ICN, ICT
• active conductor Al/Ol 450/75 mm2
• shield conductors: 1-55 dead end and 64-122 dead end St 70 mm2; 55-64 terminals
St 95 mm2
• insulation CTS 120-2P şi CTS 160 (glass insulators with 146 mm, respectively 170
mm heights).
9/27
3. Adopted reconductoring solutions and types of
Table 2
conductors used
HTLS types of conductors that are
currently on the market, are
summarized in Table 2
10/27
3. Adopted reconductoring solutions and types of
conductors used
On existing lines, increased transmission capacity is restricted by the existing
structure security. To maintain safe operation of the line, reusing the towers and
insulator chains, in case of using unconventional conductors (compact, HTLS), the
next restrictions must be followed:
 The new conductor diameter must be less or equal then the existing conductor
diameter (29,25 mm)
 The maximum horizontal traction of the new conductor, must not exceed the
existing conductor traction (Tmax = 5362 daN), in order to reduce the impact
against the poles and foundations
 The final sag of the new conductor, at maximum operating temperature, to be
limited to the final arrow of existing ACSR type conductor 450/75 mm2
 The breaking force of the new conductor should be greater or at least equal with
the existing conductor AlOl type 450/75 mm2
 Electrical distances must be maintained
11/27
3. Adopted reconductoring solutions and types of
conductors used
Table 3
The main technical and
physical data of conductors
selected for analysis – Table 3
12/27
3. Adopted reconductoring solutions and types of
conductors used
Table 4
Physical parameters for HTLS
conductors – Table 4
13/27
3. Adopted reconductoring solutions and types of
conductors used
Table 5
Real carrying capacity for
HTLS conductors– Table 5
14/27
4. LM technologies proposed for implementation
Critical circuits reconductoring, a solution with clear benefits, which may
increase thermic capacity twice or more, faces two major obstacles:
 involved towers, in most cases, have the life span very high (close to the
lifetime) and if the maintenance works were not made under the rules, they
will be repaired and strengthened
 circuits which have the greatest need to be reconductorated are usually the
most difficult to be withdrawn from operation.
If you can’t find a way to achieve LMT for the whole work, it is necessary to
find combined technologies with which to achieve reconductoring works
with the line withdrawn from service and into a short a period of time.
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4. LM technologies proposed for implementation
Taking into account the existing technologies at this time in Romania and
the existing facilities, there are imposed some restrictions in applying the
live-line technologies to this line:
 there can’t be done works at the towers on the middle phase on 220 kV
single circuit OHL
 there can’t be performed works on the energized upper phases, on double
circuit segment of that line (towers 470-472)
For this reason the live-line technology will be applied only to two of the
three phases of the line. Preparatory work that can be done under voltage:
 vibration dampers removal
 clamps replacement at the lower roller yokes
 final work that can be done live-line:
- vibration damper installation
- suspension clamps mounting (clamping)
16/27
4. LM technologies proposed for implementation
Table 6
Reconductoring deployment sequence
work and line status - Table 6
17/27
4. LM technologies proposed for implementation
The live-line progress of work necessarily involves attending the following:
 determining atmospheric conditions at the workplace by the Head of works
 preparation of ladder and chair
 equipping workers climbing on the poles with the conductive material suits and
shoes with electroconductive soles
 training employees in the team and the allocation of duties
 undervoltage working authorization signature by all team members
 mounting the trolley at climbing pole
 worker shift from the trolley to phase wire
 trolley movement, directed from the ground with rope guidance
 truck passing on a support pole
 removing the trolley at descent pole
 completion of the work
18/27
5. Evaluation of economical efficiency of reconductoring
For economic analysis of possible solutions of reconductoring with increased
transportation capacity conductors were compared the variants with conductors who
met the necessary technical conditions to achieve a corresponding increase in
transmission capacity. In this analysis were examined two components: direct costs
and maintenance total cost respectively cost of energy losses.
Table 7
All costs below are calculated for a
kilometer of three-phase circuit, equipped
with one conductor per phase.
In Table 7 are shown power losses
calculation for different types of
conductors.
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5. Evaluation of economical efficiency of reconductoring
Using a conductor with a specific resistance lower gives two advantages: lower
losses and reduced operating temperature. Power losses values per unit in MW/km
are shown in Fig. 4.
Fig. 4
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5. Evaluation of economical efficiency of reconductoring
Taking into account (maximum) a carried power of 480 MVA for 8760 hours per year,
present value of power losses for 30 years, with a discount rate of 8%, is shown in Fig. 5.
Actualized costs of power losses
1482856
1279109
1600000
1143439
1052218
1400000
913862
Euro/km
1200000
1000000
800000
600000
400000
200000
Fig. 5
0
ACSS
ZTACIR
GZTACSR
ACCR
ACCC/TW
21/27
5. Evaluation of economical efficiency of reconductoring
Total direct costs, including procurement, installation and maintenance upgrade,
according to Fig. 6, are the lowest for ACSS conductor followed by GZTACSR.
Direct costs (Euro/km)
217000
250000
144900
Euro/km
200000
150000
89200
83100
100000
46980
50000
0
Fig. 6
ACSS
ZTACIR
GZTACSR
ACCR
ACCC/TW
Conductor
22/27
5. Evaluation of economical efficiency of reconductoring
Finally the comparison of total costs (cost of losses + direct costs), as shown in Fig. 7
reveals that the ACSS and ACCC/TW are the most recommended conductors suitable
for the examined case.
Actualized total cost (direct + losses)
1566000
1368300
1600000
1400000
1360600
1099200
1058700
Euro/km
1200000
1000000
800000
600000
400000
200000
Fig. 7
0
ACSS
ZTACIR
GZTACSR
ACCR
ACCC/TW
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6. Conclusions
The software tool developed by the authors is designed for congestion management.
It corresponds to the actual operating conditions, represented by the deregulated
environment. Within the paper the results are used as an application for the
reconductoring process
Based on the analyses performed using the software two OHLs have been identified
as candidates. One of them is suitable for reconductoring, having the highest
efficiency
The usage of HTLS type conductors on the 220 ​kV OHL Iernut-Baia Mare is technically
feasible; all analyzed conductors, less TACSR, may be used, having a sag equal or
less than the current one, but with a higher thermal current
Similar diameters of wires lead to wind forces similar to those for which the line was
designed and achieve a minimal visual impact
The growth of thermal current implies an increase in the values ​of the magnetic field,
but below the amount prescribed by the ICNIRP
24/27
6. Conclusions
The ACCC and ACCR conductors, composite types, have the best mechanical and
electrical pair of values characteristics; they are relatively new products on the
market, are not yet widely used, and the direct cost is higher compared to other types
ZTACIR type conductors are used mainly in Japan and Korea, and the direct cost for
hese conductors is lower than that of the composites ones. Given the normal frost
deposits on the analysed OHL, these types of conductors can be
considered
as a feasible solution
GZTACSR type conductors can be considered feasible, subject to a special
installation, the need for a training and a high maintenance
ACSS type conductors have the lower direct costs correlated with a good electrical
resistance, installation and maintenance comparable to conventional ACSR
conductors
ZTACIR type conductors are used mainly in Japan and Korea, and the direct cost for
these conductors is lower than that of the composites ones. Given the normal frost
deposits on the analysed OHL, these types of conductors can be considered as a
feasible solution
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6. Conclusions
 about the direct costs of procurement, installation and maintenance, the ACSS
conductor type stands in first place, followed by the GZTACSR and ZTACIR
conductor
 related to the costs of energy losses, the ACCC, ACSS and ACCR conductor types
are located on top, in this order
 for reconductoring of the 220 kV OHL Iernut-Baia Mare is proposed the ACSS
conductor type
 combined technology proposed for completion of the 220 kV OHL Iernut-Baia Mare 3
reconductoring greatly reduces the time of withdrawal operation.
26/27
Thank you for your attention !
Thank you for your attention !
27/27