Optimal Solutions for Power Grid Development Problems

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The MAIN JOURNAL for POWER GRID SPECIALISTS in RUSSIA


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34

Optimal Solutions
for Power Grid 
Development Problems

Victor FOKIN,

Director of Energoservis, 
LLC

Vasily KURYANOV,

Ph.D., Head of Power and 
Electrical Engineering 
Department, National 
Research University 
"Moscow Power 
Engineering Institute"

Lyudmila KUSHCH,

Ph.D., Associate Professor 
of Power and Electrical 
Engineering Department, 
National Research 
University "Moscow Power 
Engineering Institute"

Alexander 

MERZLYAKOV,

Head of Composite 
Materials Department, 
Center for Composite 
Materials and Super-
conductivity, Administration 
of Innovative Equipment 
and Energy Ef

fi

 ciency,

JSC STC FGC UES

In the conditions of constant power consumption increase, the 

problem of optimizing long-distance energy 

fl

 ows transmission 

needs to be solved. One solution could be the creation of innova-

tive conductors providing transmission capacity enhancement 

while reducing technical power losses, including corona losses.

P

roducts developed by LLC Energoservis 
and JSC Severstal are compacted conduc-
tors characterized by increased mechanical 
strength and current load. In comparison 

with ordinary conductors, the compacted conduc-
tors are twisted and constricted by means of plastic 
deformation. As a result, the compacted conductor 
has a higher density in the cross section and con-
ductive electrical contacts between the wires. ASHS 
and ASHT conductors (high-strength and high-tem-
perature steel-aluminum conductors) [2, 5, 7] are 
certi

fi

 ed for use at power transmission lines by PJSC 

FGC UES interdepartmental commission [1, 2]. The 
conductors have passed tests on mechanical and 
electrical parameters, including on corona discharge 
and its intensity in accordance with IEC 61284:1997 
re commendations ("Overhead lines – Requirements 
and tests for 

fi

 tting") [3, 4, 5]. Comparative analysis of 

test results is considered below.

OPTIMAL SOLUTIONS

FOR POWER GRID DEVELOPMENT 

PROBLEMS

Currently, the improvement of the power grid ef

fi

 -

ciency is one of the most topical issues. One solution 
is the implementation of innovative conductors with 
better characteristics in relation to standard steel-
aluminum conductors. Among those characteristics 
are enhanced transmission capacity and mechanical 
strength, as well as resistance to high temperatures, 
aging and aggressive environmental in

fl

 uences.

Usually, the problems of power grids development 

around the world are solved by means of existing 
power lines reconstruction (preferably using old trans-
mission towers). Sometimes, the reconstruction is 
performed with transmission capacity enhancement. 
If the reconstruction can't provide satisfactory result, 
new overhead lines construction is carried out. The 
use of new technologies is logical for any solution.

The conductors and overhead ground-wire cables 

produced with unique plastic deformation technology 
application allow to reduce price and have advanced 
characteristics (the 

fi

 rst prize of PJSC ROSSETI for 

the best implemented project in 2014). Taking into 

o

v

e

r

h

e

a

d

 t

r

a

n

s

m

is

s

io

n

 l

in

e

s

overhead transmission lines


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35

account the large-scale program of 
transmission lines constructions and 
reconstructions in Germany, France, 
Italy and other EEC countries, the 
use of afore-mentioned conductors 
can signi

fi

 cantly reduce construc-

tion costs. ROSSETI Group has al-
ready implemented 8 overhead line 
projects and has installed 18000 km 
of overhead ground-wire cables in 
Russia. In addition, 17 overhead line 
projects are under implementation.

Experimentally con

fi

 rmed  main 

advantages of ASHS/ASHT mo-
dern conductors in comparison with 
traditional steel-aluminum ones are 
listed below:

 

– wind loads reduction;

 

– less susceptibility to conductor 

galloping and vibrations self-
damping;

 

– less probability of snow adhering;

 

– greater mechanical strength and, 

as a consequence, smaller sags 
and the possibility of increasing 
the distance between transmis-
sion towers;

 

– electrical resistance reduction;

Table 1. Wind loads for conductors with different cross-section contour depending on air

fl

 ow speed

Air

fl

 ow speed 

v

AB

. m/s

Wind load acting on the following conductors. N/m

ASHS 128/37

(Ø15.2 mm)

ACSR 120/19

(Ø15.2 mm)

ASHS 216/33

(Ø18.5 mm)

ACSR 240/32

(Ø21.6 mm)

ASHS 277/79

(Ø22.4 mm)

ACSR 240/56

(Ø22.5 mm)

25

3.6

4.8

4.9

6.9

5.2

7.0

32

5.9

7.9

7.8

11.4

8.4

11.5

60

20.8

28.5

28.4

41.5

29.8

41.6

 

– corona losses reduction;

 

– enhanced permissible current 

(for high-temperature conductor).
ASHS/ASHT conductor advan-

tages are con

fi

 rmed by the results 

of the research conducted by PJSC 
FGC UES science and technical 
center, National Research Univer-
sity "Moscow Power Engineering 
Institute", Volgograd State Technical 
University and other leading scien-
ti

fi

 c centers.

The interactions of wind and con-

ductors depending on wind speed 
and type of conductors cross-
section have been compared. The 
following conductors with similar 
diameters have been used for com-
parison (Table 1): ASHS 128/37 and 
ACSR 120/19; ASHS 230/32 and 
ACSR  240/34;  ASHS  277/79  and 
ACSR 240/56. There is the differ-
ence between calculated and stan-
dard wind loads, because wind pres-
sure changes (depending on relief 
of the terrain), impact of span length 
on wind load and intermittent wind 
pressure along overhead transmis-

Figure 1. Dependence of permissible current load on ambient temperature

Ambient temperature, °C

– ACSR 258/73

– ASHT 240/39

I

per

, A

–30

–20

1600

1400

1200

1000

800

600

400

200

–10

0

10

20

30

40

T

max

 = 80°C

T

max

 = 150°C

sion lines are not taken into account. 
Taken approach makes it possible to 
more clearly determine the contribu-
tion of conductor contours to wind 
load changes. The view of conduc-
tors contour after crimping was ob-
tained by modeling steel-aluminum 
conductor plastic deformation pro-
cess in the Abaqus/Explicit mod-
ule of the SIMULIA/Abaqus soft-
ware (Abaqus, Inc., USA). For all 
ASHS conductors aluminum wires 
of outer layer are tightly adjacent to 
each other without gaps. It provides 
a possibility to simulate the wind 
impact on a single conductor with 
one external contour by means of
COMSOL Multiphysics.

As can be seen from the data 

above, wind load on ASHS conduc-
tors having streamlined design is 
lower by 33% on the average. Reduc-
tion of wind load makes it possible to 
reduce the load on power transmis-
sion structures and to mount con-
ductors with greater transmission 
capacity to existing towers during 
capital repairs. Plastically crimped 
wires have a number of advan-
tages, which are usually inherent in 
more expensive wires from pro

fi

 led 

wires. According to re ference data, 
the loads from ice coating action on 
compacted conductors with smooth 
outer surface and reduced diameter 
are decreased by 3-9% compared 
to standard steel-aluminum conduc-
tors of the same section [6].

It should be noted that, accord-

ing to regulatory documentation, 
standard conductors are allowed 
to operate when their temperatures 
is up to 80-90°C. The permissible 
temperature for ASHT conductors is 
150°C.

Figure 1 represents the depen-

dence of permissible current load 
on the air temperature (wind speed 
is 1.2 m/s) for ACSR and ASHT 
conductors in conditions of a maxi-
mum operating temperature of 80°C 

47th CIGRE Session 

Special issue, August 2018


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36

OVERHEAD

TRANSMISSION LINES

Figure 2. Dependence of corona discharge points number on voltage

Voltage, kV

Corona discharge points number

, pcs

– ACSR 150/19

– ACSR 185/29

– ASHS 197/55

– ACSR 220/32

30

25

20

15

10

5

0

and 150°C, respectively. Continu-
ous permissible current for high-
tempera ture conductor is 30-35% 
higher than the value for standard 
conductor of the same diameter. 
This characteristic (Figure 1) allows 
innovative conductor application 
when signi

fi

 cant increase of trans-

mission ca 

pacity, without increas-

ing the cross-section, is required. 
Also, the innovative conductor can 
be used in areas with high ambient 
temperatures.

THE STUDY OF CORONA 

DISCHARGE OCCURRENCE 

AS A FUNCTION OF VOLTAGE

An important point when using con-
ductors with less diameter is the risk 
of corona losses and noise levels 
enhancement. JSC STC FGC UES 
conducted two studies for testing 
this problem. At the 

fi

 rst stage, two 

conductors of the same diameter 
(18.8 mm) were taken for comparing 
and studying corona discharge. In 
total, 4 conductors have been used 
within the experiment (Table 2 and 
Figure 2).

The tests were carried out in ac-

cordance with IEC 61284 recom-
mendations.

Based on comparative tests re-

sults obtained at PJSC FGC UES 
science and technical center, it was 
established that ASHS 197/55 con-
ductor manufactured by LLC Ener-
goservis has corona discharge volt-
age (142.2 kV) by 5.7% higher than 
ACSR 185/29 conductor (134.5 kV) 
with the same diameter 18.8 mm.

Similar tests were carried out for 

ASHS 216/33 and ACSR 240/32 
conductors with different diam-
eters. Based on comparative tests 
results ACSR 240/32 conductor 
(Ø21.6 mm) and ASHS 216/33 con-
ductor (Ø18.5 mm) have the same 
corona discharge voltage. However, 
continuous permissible current of 
the conductors being compared dif-
fers signi

fi

 cantly (510 A for ACSR 

240/32 conductor, 689 A for ASHS 
216/33 conductor (

t

 = 70°C), and 

1040 A for ASHT 216/33 conductor 
(

t

 = 150°C)).

ASHS conductors have advan-

tages in terms of smaller corona 
losses in comparison with ACSR 
conductors of the same diameter. 
Also, ASHS conductors have com-
parable corona losses in regard to 

100

120

140

160

180

Figure 3. Span length with allowable clearance spans for OHL

Table 2. Technical data of the tested conductors

Conductor 

model

Conductor 

external

diameter, mm

Number of alumi-

num wires in the 

conductor, pcs

Diameter of 

outer layer 

wires, mm

Con tinuous 
permissible

current

ACSR 

150/19

16.8

24

2.8

450

ACSR 

185/29

18.8

26

2.98

510

ASHS/ASHT 

197/55

18.8

28

3.45

561/943*

ACSR 

240/32

21.6

24

3.6

605

t

max

 = 70°C – high-strength steel-aluminum conductors and

t

max

 = 150°C – high temperature steel-aluminum conductors


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37

REFERENCES
1.  Fokin V.A., Kolosov S.V. A new generation of overhead 

lines: plastically deformed conductors. 

ELEKTROENER-

GIYa: peredacha i raspredelenie

 [ELECTRIC POWER: 

Transmission and Distribution], 2014, no. 1(22), pp. 90-93. 
(in Russian)

2.  Gurevich L.M., Vlasov A.K., Fokin V.A. New types of plasti-

cally deformed conductors, overhead ground-wire cables 
and OPGW. 

ELEKTROENERGIYa: peredacha i raspre-

delenie

 [ELECTRIC POWER: Transmission and Distribu-

tion], 2015, no. 5(32), pp. 66-71. (in Russian)

3. Gurevich L.M., Danenko V.F., Pronichev D.V., Trunov 

M.D. Modeling of electromagnetic losses in various steel-
aluminum conductors. 

ELEKTROENERGIYa: peredacha i 

raspredelenie

 [ELECTRIC POWER: Transmission and Dis-

tribution], 2014, no. 5(26), pp. 68-72. (in Russian)

4.  Test report no. 22-06-2018. Moscow, JSC STC FGC UES 

Publ., 2018. (In Russian).

5.  Test report no. BO13-112016. Moscow, JSC STC FGC 

UES Publ., 2016. 15 p. (In Russian).

6. Serbinovskiy G.V., Fedorov A.A. 

Spravochnik po elek tro-

snab zheniyu promyshlennykh predpriyatiy. Kn. 1. Pro-
yekt no-ras chetnyye svedeniya 

[Handbook on industrial 

enterprises power supply. Book 1. Design and calculation 
information.]. Moscow, Energiya Publ.,1986. 576 p.

7.  Kuryanov V.N., Shvets E.S., Timashova L.V., Fokin V.A. 

Application of domestic innovative ASHT high-tempera-
ture conductors for 110 kV overhead lines and their ef

fi

 -

ciency. 

Energiya edinoy seti

 [Energy of uni

fi

 ed grid], 2017, 

no. 5(34), pp. 12–18. (in Russian)

Calculated speci

fi

 c corona losses in good weather

(220 kV overhead line)

Phase construction

(conductor model;

conductor radius 

r

0

, cm)

Annual average

losses change, %

ACSR 240/32;

 Ø

 21.6 mm

+ 26.67%

ACSR 300/39;

 Ø

 24.0 mm

0.00%

ACSR 330/43;

 Ø

 25.2 mm

–13.33%

ASHS 317/47;

 Ø

 22.3 mm

–13.33%

ASHS 295/44;

 Ø

 21.5 mm

–6.67%

Calculated speci

fi

 c corona losses in good weather

(330 kV overhead line with split phase consisting

of 2 conductors with 40 cm spacing)

Phase construction

(conductor model;

conductor radius 

r

0

, cm)

Annual average 

losses change, %

2 × ACSR 300/39;

 Ø

 24.0 mm

+ 18.52%

2 × ACSR 400/51;

 Ø

 27.5 mm

0.00%

2 × ASHS 317/47;

 Ø

 22.3 mm

–7.41%

2 × ASHS 295/44;

 Ø

 21.5 mm

+ 3.70%

ACSR conductors with larger diam-
eter and similar electrical and me-
chanical characteristics.

The examples of design solutions 

(Figure 3) illustrate signi

fi

 cant expan-

sion of optimization possibilities.

CONCLUSION

As a result of numerical experi-
ments, a study of ASHT modern 
high-temperature conductors ap-
plication ef

fi

 

ciency in electrical 

network has been made. The data 
on the ultimate loads, the reduc-
tion of heat release and magneti-
zation of the conductors in opera-
tion have been obtained. Based 
on comparative tests results it was 
established that ASHS conduc-

tors have corona discharge volt-
age higher, than ACSR conductors 
with the same diameter.

The  relative  decrease  of  ASHT 

high-temperature conductor mag-
netization in comparison with ACSR 
conductor is 3-7%. The obtained 
results  show  that  innovative  con-
ductor application is justi

fi

 ed  when 

signi

fi

 

cant increase of transmis-

sion capacity without increasing the 
cross-section is required. Also, the 
innovative conductor can be used 
in areas with high ambient tempera-
tures. When reconstructing 110 kV 
and above electrical networks, the 
economic effect of ASHT conduc-
tors  application  is  achieved  by  re-
ducing magnetization, heat and 

corona losses as well as increas-
ing network capacity and improving 
power supply reliability. Consider-
ing the fact that currently existing 
power transmission lines have been 
in operation for more than 25-40 
years and have depleted their re-
sources, it is extremely necessary 
to replace them with new ones.

On a per 1 km basis of 110 kV 

conductor in the Volgograd Region, 
the discounted payback period for 
the replacement of a standard con-
ductor with ASHT high-temperature 
conductor (manufactured by LLC 
Energoservis) does not exceed 
5 years. It changes the approach to 
high-temperature conductors appli-
cation. 

 

Р

Average characteristics of overhead lines in Russia

Voltage, kV

220

330

500

750

Average length of overhead line, km

59

88

187

250

Average diameter of ACSR conductor, mm

25.6

25.6

27.4

26.1

Possible ASHT / ASHS conductor

diameter in terms of corona discharge

22.4

22.4

24.5

24

Energoservis, LLC

rsppvo1@mail.ru

energoservice2@yandex.ru

www.energoservise.com

47th CIGRE Session 

Special issue, August 2018


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In the conditions of constant power consumption increase, the problem of optimizing long-distance energy flows transmission needs to be solved. One solution could be the creation of innovative conductors providing transmission capacity enhancement while reducing technical power losses, including corona losses.

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