Case Study on Increasing the Transport Capacity

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 4

Prof. dr. Ştefan KILYENI 5, As. dr. Constantin BĂRBULESCU 5

1 Romanian Power Grid Company C.N.T.E.E. “Transelectrica” SA, Timişoara Subsidiary, Romania2 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

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http://www.cacier.com.ar/Reuniones/2011CITTES/index.htm

1. Introduction2. OHL identification in the West part of NPG, in which the reconductoring has maximum efficiency3. Adopted reconductoring solutions and types of conductors used4. LM technologies proposed for implementation5. Evaluation of economical efficiency of reconductoring6. Conclusions

Content

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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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Summary of key methods and instruments used to increase OHL capacity - Table 1

1. Introduction

Table 1

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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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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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XPF_ DJ1185

P.D.FIE28004

P.D.F.B28046

TR.SEV28048

CETATE128050

CALAFAT28051

TR.S.ES28719

CETATE29102

CALAFAT28709

RESITA28052

IAZ 1

RESITA B28730

IAZ A28736

28054

TIMIS28071

TIMIS A

1 2

SACALAZ28070

SACALAZ28756

ARAD28069

ARAD28008

XSA_ AR1175

ARAD B28775

ARAD A28774

URECHESI28002

URECHESI28045

TG.J IU28062

URECHEST28694

PAROSEN28063

BARU M28064

HAJD OT.28065

BARU MA28800

HASDAT28795

2

1R.MARE28914

PESTIS28066

MINTIA B28068

PESTIS28792

MINTIA28003

MINTIA A28067

LOTRU28040

SIBIU28100

2

1

LOTRU28562

SIBIU28034

1

2

SIBIU S

SIBIU SB28537

28538

P.D.F.A28047

1 2

TR.SEV28049

28729RESITA A

IAZ 228053

IAZ B28737

28746 28747TIMIS B

ORAD I I28839

BAIA MA328484

BAIA MA28485

BAIA M.28093

ROSIORI28094

ORADEA28096

ROSIORI28039

XRO_ MU1184

1

2

VETIS28095

VETIS28491

GADALIN28037

CLUJ E28038CLUJ ES

28509

IERNUT28087

UNGHENI28086

IERNUT28036

UNGHE.A28459

UNGHE.B28460

IERNUT28524

CUPT.C.T28088

1

2

1

2

MINTIA28787

12

P.D.F 429192

P.D.F 329191

P.D.F 229190

P.D.F 529193

P.D.F 129189 P.D.F.6

29250

MINTIA 529169

MINTIA 329260

MINTIA 629262

PAROSEN28808

RETEZAT129162

ROVIN 529119

ROVIN 629120

ROVIN 329121

ROVIN 429238

ROVIN 729455

IERNUT 529159

IERNUT 629160

LOTRU 129232

LOTRU 229233

MINTIA 129167

111.5 MW 8.1 MVR 111.5 MW

8.1 MVR

-7 MVR 111.5 MW

-7 MVR 111.5 MW

-7 MVR 111.5 MW -7 MVR

111.5 MW

269 MW 109 MVR 109 MVR

229.6 MW 258.3 MW 47.2 MVR

0 MW 0 MVR

0 MW 0 MVR

327.9 MW -22.3 MVR

629.7 MW -66.4 MVR

91.2 MW 41.6 MVR

61.6 MW -16.6 MVR

228.4 MW 73.5 MVR

277.1 MW -14.9 MVR

123.2 MW 5.0 MVR

16.9 MVR 1.0 MW

99.0 MW -11.3 MVR

98.2 MW-11.4 MVR

193 MW 118 MVR

193 MW 111 MVR

72.3 MW -12.4 MVR

157.6 MW 21.9 MVR

150.8 MW 21.7 MVR

150.0 MW 22.1 MVR

0.0 MW 0.0 MVR

20 MVR

59.2 MW

21.3 MVR 39.3 MW 66.0 MW

0.4 MVR

-12 MVR 14.8 MW

3.4 MVR 7.4 MW 18.7 MW

-11.1 MVR

-27 MVR 81.8 MW

57 MW 15.2 MVR

26 MW 19.8 MVR

63.6 MW 7.1 MVR

75.0 MW 10.8 MVR

1.2 MW 0.6 MVR

79.2 MW 9.1 MVR

43.8 MW 3.6 MVR

53.8 MW 65.5 MVR

70 MW 6 MVR

84.8 MW 46.9 MVR

18.6 MW 6.1 MVR

25.7 MW -4.4 MVR

45.4 MW -8.0 MVR

8 MVR 39.8 MW

47.4 MW 7.2 MVR

6.2 MW -1.4 MVR

55.8 MW 9.5 MVR

15.9 MW 2.7 MVR

26.7 MW 3.9 MVR

59.2 MW 12.9 MVR

16.1 MW -0.7 MVR

71.0 MW 12.5 MVR

57.1 MW 12.3 MVR

50.6 MW -0.1 MVR 78.9 MW

18.2 MVR

52.1 MW 14.3 MVR

17.5 MW -11.7 MVR

85.1 MW 21.1 MVR

82.5 MW -3.2 MVR

0.6 MVR 113.8 MW

89.2 MW -1.4 MVR

0 MW -0.9 MVR

50.1 MW 19.1 MVR

48.9 MW 18.7 MVR

0.5 MW 0.0 MVR

87.2 MW 16.5 MVR

25.5 MW 4.7 MVR

51.7 MW 7.7 MVR

62.6 MW 22.8 MVR

23.8 MW 10.9 MVR

17.8 MW 9.9 MVR

-60 MVR 219.8 MW

-57.2 MVR

10.1 MW 1.5 MVR

21.9 MW 3.0 MVR

-100.6 MVR

-179.2 MVR

-96.6 MVR

86%

85%

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.

Fig. 3

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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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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).

3. Adopted reconductoring solutions and types of conductors used

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HTLS types of conductors that are currently on the market, are summarized in Table 2

Table 2

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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

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The main technical and physical data of conductors selected for analysis – Table 3

Table 3

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Physical parameters for HTLS conductors – Table 4

Table 4

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Real carrying capacity for HTLS conductors– Table 5

Table 5

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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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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)

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Reconductoring deployment sequence work and line status - Table 6

Table 6

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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

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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.

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.

Table 7

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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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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.

Fig. 5

1052218

1482856

12791091143439

913862

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

Eur

o/km

ACSS ZTACIR GZTACSR ACCR ACCC/TW

Actualized costs of power losses

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Total direct costs, including procurement, installation and maintenance upgrade, according to Fig. 6, are the lowest for ACSS conductor followed by GZTACSR.

Fig. 6

46980

8310089200

217000

144900

0

50000

100000

150000

200000

250000

Eu

ro/k

m


Conductor

Direct costs (Euro/km)

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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.

Fig. 7

1099200

1566000

1368300 1360600

1058700

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

Eu

ro/k

m


Actualized total cost (direct + losses)

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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

6. Conclusions

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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

6. Conclusions

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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.

6. Conclusions

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Thank you for your attention !

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Thank you for your attention !

Documents

Case Study on Increasing the Transport Capacity