Prospects of Implementation of Electrotechnical Equipment with Superconductivity Technology Elements in JSC “UNECO”

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August 25–29, France, Paris



oscow energy system supplies power to 
consumers in the territory of Moscow City 
and Moscow Region, with the total area 
of 47 000 m


 and population of over 19 

million people.

The absolute load peak value of Moscow energy system 

reached 18052 MW (historical peak), power consumption 
in 2012 amounted to about 100.9 TW•h (about 44% of 
IES of Center power consumption, which corresponds to 
nearly 10% of UES of Russia power consumption).

Power grids 750, 500, 220, 110 kV and below, which 

include 566 substations (2 — 750 kV, 11 — 500 kV, 
90 — 220 kV, 463 — 110 kV; installed transformer 
capacity of about 65 thousand MVA), 998 transmission 
lines with total length of approximately 16700 km, operate 
in the territory of Moscow energy system.

A characteristic feature of Moscow energy system is 

basic power 


 ows from north to south. This is explained 

by the fact that basic electric power sources are located in 
the north and north-west of IES of Center.

According to JSC “Energosetproyekt Institute”, the 

existing power balance of IES of Center re


 ects on the 

load of OHL and CL between the northern and southern 
parts of Moscow energy system, which manifests itself 
in a decrease of the total capacity of backbone networks 
between Moscow energy system and other energy systems 
included in IES of Center. In this case there are transit 



 ows in 110 and 220 kV grids between the northern 

and southern areas of Moscow. Such a situation is believed 
to remain in the nearest and long-term perspectives.

Increasing capacity of links between the northern 

and southern areas of the metropolitan city will require 
increasing the number of lines 220 kV or construction 
of load-center substations 500 kV, with their connection 
to load centers 500 kV located along the Moscow ring 
500 kV. 

During construction of new parallel transmission 

lines 500 kV there arise dif


 culties related to allocation 

of land for line routes, as main backbone lines 500 kV, 
which require reinforcement (doubling), are located in 
close proximity to the city, with its ongoing mass housing 

At present, power supply of Moscow central area is 

mainly carried out by means of cable transmission lines 
(CL). The consumer load amounts to approximately 2000 
MVA and is covered by means of receiving power from 
feeder centres, located in the city periphery (substations 
500 kV “Ochakovo”, “Chagino”, “Beskudnikovo”, large 
TPPs). Increasing demand for electricity causes a relevant 
problem of meeting this demand, which can be solved by 
creating additional power sources (construction of power 
plants) and construction of load-center substations.

Since construction of power plants in the city center 

requires allocation of extensive territories, while their 

Prospects of Implementation 

of Electrotechnical Equipment 

with Superconductivity 

Technology Elements in JSC 


Andrey MAYOROV (




), General Director,

Vitaly NAUMOV (





 Head of Department of Advanced Projects, JSC “United Energy Company”,





), General Director,

CJSC “SuperOx”

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operation can impair ecology and architecture of the area, 
one of alternatives is increasing capacity of transmission 
lines, which can be achieved by increasing voltage and/or 
rated operating current.

One of radical problem solutions might be the variant 

of transfer to a higher voltage level — 500 kV, developed 
by JSC “Energosetproyekt Institute”: construction of 
an overhead line — 500 kV (OHL 500 kV), capable of 
transmitting power of up to 2000 MVA; however, this 
variant is unacceptable in the city center.

Construction of a cable line 500 kV (CL 500 kV) in 

ground or a tunnel does not require allocation of extensive 
territories; however, comparing to OHL 500 kV, its speci



capacitance is 12—15 times as high. Compensation of 
reactive power generated by CL 500 kV requires installing 
compensating devices (FACTS) with total capacity of 
approximately 900 MVA. Placing such equipment (with 
monitoring and 


 re-extinguishing systems) at substation 

sites in the city center is extremely undesirable.

A promising solution to the load-center problem 

in Moscow central districts is implementation of gas-
insulated (gas-


 lled) transmission lines (GIL), in which 

SF6 dielectric gas is under excessive pressure.

One of the 


 rst industrial installations GIL 420 kV 

was developed by Siemens and commissioned in 1975 
at Wehr Pumped Storage Hydroelectric Power Plant in 
Schwarzwald Mts. (Baden-Wurttemberg state). GIL pipe 
diameter for a single-phase line 400 kV is approximately 
500 mm, and three pipes are required for a three-phase 
line. As for the underground version, the tunnel size for 
two three-phase GIL should correspond in diameter to 
3.5 or 2.5 m in height and 2.8 m in width. One should 
note that in the 70s of the last century in our country 
GIL 110 and 220 kV were designed, manufactured and 
put in pilot operation, which was followed by bench 
tests of GIL 500 kV. However, 
inadequate technology lying 
in the basis of these devices 
impeded their promotion onto 
Russian market.

Another variant suits for crea-

tion of high-capacity transmis-
sion lines, and this is implemen-
tation of superconductors. 

Superconductivity, i.e. disap-

pearance of electric resistance in 
a number of materials at low tem-
peratures, was discovered in 1911, 
but search for ways to produce us-
able materials lasted for almost 
half a century. Niobium-based 
superconductors appeared only in 
1960s and quickly occupied their 
place in powerful magnetic sys-
tems (medical CT scanners, accel-
erators). Use of these supercon-
ductors in power engineering was 

considered and prototypes of cable systems were designed; 
however, a need in using expensive liquid helium and com-
plex cryogenic systems prevented this technology from be-
ing put into practice. The situation changed at the end of 
1980s after discovery of superconductivity in ceramic com-
pounds. Superconductors of this family have an abnormally 
“high” temperature of transition into superconductive state, 
which can vary from 90 to 130 


 (-143 — -180



) for vari-

ous substances. This means that there emerged a possibility 
of using liquid nitrogen instead of unrenewable expensive 
liquid helium for cooling superconductors to operating tem-
peratures. New superconductors were called high-tempera-
ture ones (HTS).

Among HTS conductors, several cable systems have 

been designed and put in pilot operation in Germany, USA, 
Korea, Japan and other developed countries (Fig.1, 2, 3). 
Operation within a real grid demonstrates high reliability 
of these systems. 

An important factor enabling signi


 cant simpli



of HV insulation of HTS cables is very high dielectric 
strength of liquid nitrogen, which is used as a cooling 
agent (10—50 kV/mm, depending on pressure, nitrogen 
purity and geometry). These values are comparable to 
dielectric strength of transformer oil, which makes it 
possible to greatly reduce the thickness of insulation layer 
and HV cable size. 

Main advantages of superconductive cable lines, in 

addition to their compact size, are the following: 

no electromagnetic 


 eld outside the cable. As a rule

HTS cable design includes a shield of HTS tapes, 
which prevents radiation from penetrating outside the 
cable sheath. In particular, this enables laying HV CL 
in ground; 


no heat release

. Due to the fact that superconductor 

operating temperature is extremely low, HTS cables 

Fig. 1. AC HTS CL characteristics. Spot area is proportional 

to the cable line length

AMPACITY project

Essen, Germany

10 kV/40 MVA/1000 m

Furukawa, Japan

275 kV/1500 MVA/30 m










Voltage (kV)

Power (MV


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August 25–29, France, Paris


have vacuum thermal insulation of a very high level. 
Therefore, the temperature of cable system outer layer 
approximates the ambient temperature. This makes it 
possible to locate parallel cable HTS lines or phases in 
close proximity to each other;


long service life

. The basic criterion that limits service 

life of HV cables is insulation aging, which accelerates 
at temperature rises (current increases). Since HTS 
cables are operated at cryogenic temperatures, at which 
negative insulation aging processes are very slow, the 
expected service life of HTS CL exceeds service life of 
standard cables many times. 
Another useful property of HTS CL is relatively 

low values of inductance and capacitance. Owing to it, 
high power can be transmitted over HTS cables without 
compensating devices for long distances (hundreds of 
kilometers). In this regard, HTS CL is inferior only to an 

overhead transmission line. Table 1 shows values of basic 
parameters of OHL 380 kV, XLPE-insulation cable and 
HTS cable, according to [1]. 

It should be noted that technologies of construction 

of HTS cable systems have already been mastered in 
Russia. In 2007—2010 a group of developers (JSC 
“VNIIKP”, JSC “ENIN”, Moscow Aviation Institute, 
JSC “R&D Center for Power Engineering”) designed 
and manufactured an HTS cable, which at the time was 
the longest in Europe (20 kV, 50 MVA, 200 m) [2]. JSC 
“FGC UES” is vigorously developing a project of creating 
the world’s longest DC HTS CL in St. Petersburg (20 kV, 
50 MVA, 2500 m). Second-generation HTS conductors 
are manufactured in CJSC “SuperOx”; in 2013 two model 
cables with critical currents 3 and 4.5 kA were designed 
in JSC “VNIIKP” on the basis of such conductors [3,4]. 

As applied to Moscow energy system, superconductive 

cable lines can be implemented for introducing high power 
to the city center with the use of existing infrastructure 
or with its slight changes. For example, three phases 
of a cable with operating voltage 275 kV developed by 
Furukawa Company enable transmitting power of about 
1500 MVA, and such a cable line can be placed in a cable 
duct with 1 m width and 0.50 m height. The conductor 
current-carrying capacity can be increased by using a 
larger quantity of HTS conductor up to min.10 k


Thus, one can conclude that creation of a three-phase 

AC HTS CL with operating voltage 220 kV and transmitted 
power of 2000—3000 MVA is fully implementable 
from the technical point of view. Such a line would be 
a supercompact, energy-saving and ecological solution to 
the above-described problem. 

Development of electric energy systems (EES) is 

closely related to the general economic development 
and is characterized with sustainable growth of electric 
loads, corresponding increase of generation capacities, 
reinforcement of connections with adjacent EES 
and creation of large interconnected systems, which 
interconnect not only territories of separate countries but 
also whole continents. An inevitable consequence of such 
development is growth of short-circuit currents, which is 
especially acute in high power consumption density areas 
and metropolitan cities.

Another main problem related to grid operation in 

Moscow energy system is high fault current values.

Calculations carried out in JSC “Energosetproyekt 

Institute” showed that, with the existing grid 
sectionalization, by 2020 fault currents in Moscow energy 
system will exceed the following values:
•  63 kA on 16 existing and newly constructed energy 

facilities 500 and 220 kV;

•  80 kA on 10 energy facilities 500 and 220 kV.

At present, the basic undertaking to limit fault currents 

in Moscow energy system is sectionalization of the grid 
110 and 220 kV.

A signi


 cant number of existing sectionalization points 

of 110—220 kV grid and impossibility to increase the 

Fig. 2. Phase of HTS cable manufactured by 

Furukawa (Japan, 2013). Outer diameter 150 

mm, voltage 275 kV, three-phase CL capacity 

1500 MW

Fig. 3. Three-phase coaxial HTS cable 10 kV 

manufactured by Nexans (Germany, 2014). Outer 

diameter about 150 mm. CL capacity 40 MVA 

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number due to conditions of providing 
reliable power supply of consumers 
cause need in developing and taking 
technical measures on limiting fault 

Cost of a circuit-breaker with 

operating breaking current 80 kA and 
its size exceed the cost and size of 
the existing circuit-breaker with rated 
breaking current 63 kA almost twice, 
which is a great obstacle for placing 
such equipment at limited-space 
substation sites in the city.

Thus, max. permissible level of 

fault currents for Moscow energy 
system should be 63 kA, and switching 
equipment with rated breaking current 
80 kA can be implemented only in 
certain cases. Primary attention should 
be paid to measures on limiting fault 

Table 1. Comparison of characteristics of transmission lines 

380 kV designed as OHL, XLPE-insulation cable and HTS CL






Transmitted power, MVA




Rated current, kA




Peak current, kA



Inductance, mH/km










Resistance, mOhm/km






 c impedance Z, Ohm




Load wave impedance (U2/Z), 




Critical length


, km





  critical length is based on line speci


 c capacitive current values

Table 2. Technical and economic comparison of Moscow energy system development scenarios with 

account for measures to limit fault current levels






Negative sides

Need in CB 




tation cost, 

million euro

Scenario 1 “Conventional”




Installation of current-

limiting devices in 

110 and 220 kV grid

40 kA and 


No production of current-

limiters (CL) utilized 

in the industry. No area 

for placing CL at grid 

facility sites

500 kV — 24

220 kV —199

110 kV — 491



tive vari-


Creation of additional 

sectionalization points

in 220 kV grid, installa-

tion of CLR in 

110 kV grid

Increasing grid 

sectionalization points



Sectionalization of 

Moscow City 110 and 

220 kV grid into 

4 parts

40 kA and 


Decrease in reliability of 

power supply of consum-

ers and power output of 

power plants in repair 

and post-emergency con-

ditions, need in ALT

500 kV — 24

220 kV — 117
110 kV — 378



Installing HVDC links 

in OHL 500 kV inter-

connecting generation 

facilities of IES of Cen-

ter and Moscow ring 

500 kV substations


fault currents 

only in 500 kV 


No impact on fault 

current levels in 220 and 

110 kV grid


HVDC links 

and load 


Installing HVDC links 

in 220 kV grid and 

radial operation of 

110 kV grid


40—50 kV,


Region — 
40 kA and 


Need in extensive 

territories for installing 

HVDC links. Need in 


500 kV — 22

220 kV — 145
110 kV — 407


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Based on the conducted analysis of foreign experience 

in construction of grids in metropolitan cities and 
implemented methods and means of limiting fault current 
levels, the following four scenarios of Moscow region grid 
development with fault current limiting were developed: 
conventional, balancing, external ones, HVDC links and 
load centers.

Main results of technical and economic comparison 

of the described scenarios of Moscow energy system 
development with fault current limiting are shown in 
Table 2.

The problem of limiting fault currents is relevant 

for all countries of the world. Almost all large-scale 
power engineering companies, international research 
organizations such as CIGRE 


 IEEE, R&D centers and 

higher educational establishments in many countries, 
including Russia, try to solve this problem.

Development of new technologies and materials, 

related to converter equipment and superconductivity 
phenomenon, rapid progress in element base of power 
electronics and high-temperature superconductive 
materials (HTS) make it possible to develop current-
limiters (CL, Fig. 4), HVDC links and HVDC transmissions 
(Fig. 5), FACTS, new-generation energy accumulators 
with properties that give way to wide implementation of 
such devices in power industry. 

By present, more than 15 prototypes of superconduc-

tivity-based electrotechnical equipment for limiting of 
fault currents have been designed and tested in the world. 
Operation of these devices is based on the superconductor 

property to transition from zero-resistance state into 



conductivity state when some speci


 ed critical current 

value is exceeded. Transition from low-resistivity state 
into high-resistivity one does not require external control 
and happens very quickly (characteristic operation time 
is about 1 ms), which is a key advantage of such systems. 

Fault current limiters are actively developed in 

Germany, Italy, USA, South Korea, China. For example, a 
fault current limiter, designed for 24 kV/1 kA, was installed 
in 2013 as a busbar switch 15 kV of adjacent transformers 
on Majorca Island, Spain (ENDESA grid company); this 
device was manufactured by Nexans Superconductors 
(Germany). A fault current limiter, designed for 
115 kV/900 A, was developed by Siemens (Germany), 
now this device is in pilot operation in USA grid 
(see Fig. 4). KEPRI, Korea, is designing a superconductive 
current-limiter for 154 kV/2 kA to be installed in KEPCO 
grid; its tests are scheduled for 2014. In China in 2011 an 
HTS inductive fault current limiter, designed for 220 kV 
and 800 A, was commissioned on Shigezhuang substation 

As it was stated earlier, the issue of limiting fault 

currents in 110 and 220 kV grids of Moscow energy 
system is extremely acute. Therefore, implementation 
of breakthrough technologies based on high-temperature 
superconductors is especially relevant for Moscow City. 
Installation of a current-limiting reactor (CLR) 220 kV 
on “Mnevniki” substation was included in an investment 
program of JSC “UNECO”. Projects of construction of 
cable lines 220 kV also highlight the need in installing CL 

Fig. 4. Components of CL superconductive switch 154 kV developed by Siemens 

for the American energy system


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on “Vagankovskaya”, “Novobrattsevo”, “Tsentralnaya”, 
“Choboty” and other substations. JSC “UNECO” works 
on the issue of installing a CL superconductive switch, 
designed for 220 kV, on “Mnevniki” substation. Design 
and integration issues were discussed with specialists 
from Germany, South Korea and Russian company CJSC 

In conclusion, it should be stated that JSC “United 

Energy Company”, while keeping to the line of sustainable 
development of its power supply facilities, integration of 
innovative technologies and equipment, participates, on a 
permanent basis, in events that bring together Russian and 
foreign power industry specialists.

JSC “UNECO” suggests further works on the issue 

of construction of load-center substations fed by cable 
superconductive lines 220 kV with capacity of 2—2.5 
GW. With other conditions being equal, it is evident that 
construction costs for 220 kV HTS CL will be lower due 
to smaller sizes of cable tunnels.

Use of superconductive current limiters in 220 kV grid 

will make it possible to solve the urgent problem related 
to growth of fault currents in energy systems. 

As part of its innovative activities, JSC “UNECO” also 

intends to develop new projects based on implementation 
of superconductive equipment, such as:
•  superconductive energy accumulators with capacity 

of 0.5—1.0 MW•h, for backup power supply of 
residential consumers of metropolitan cities;

•  construction of high-capacity grids 20 kV in Moscow.

Applied superconductivity has another, equally 

important from the point of view of prospective 



elds, side, conventionally called low-

current applied superconductivity or superconductive 
electronics. For example, with implementation of SQUIDs 
(superconducting quantum interference devices), a new 
generation of non-destructive evaluation magnetometering 
systems, required, in addition to atomic, aviation and space 

industries, for PD monitoring and diagnostics of insulation 
structures in power engineering, is under development.


1.  Technical grounds for implementing superconductivity 

technologies in power engineering and power industry 
have been well established by now.

2. Potential for wide implementation of energy-



 cient superconductivity technologies is explained 

by the fact that total losses at all stages (power 
generation, distribution, consumption) can be reduced 
2.5 times, with simultaneous reduction of consumption 
of materials for devices and units 2—3 times 
only by replacing conventional equipment with 
superconductive one.

3. Implementation of the above described programs 

requires developing 


 nancial support models of 

investment projects.

4.  Taking into account the signi


  cance of superconductivity 

technologies for a whole range of industries (power 
industry, military equipment, transport, medicine, 
megascience), a multi-target system of technology 
development support with state participation should be 

5.  The task of developing superconductivity technologies, 

being an integral part of the innovative constituent of 
Russian power industry development, is relevant and 
requires immediate solution.



R. Zuijderduin, O. Chevtchenko, J.J. Smit, 
G. Aanhaanen, I. Melnik, A. Geschiere, AC HTS 
transmission cable for integration into the future EHV 
grid of the Netherlands, Physics Procedia 36 ( 2012 ) 

2. V.S. Vysotsky, A.A. Nosov, A.V. Rychagov, V.E. 

Sytnikov, S.S. Fetisov, K.A. Shutov, Development of a 

superconductive power cable based on 
HTS technologies. Project development 
and results, Cables and Conductors, 

 3, p. 3.


S. Lee, V. Petrykin, A. Molodyk, 

S. Samoilenkov, A. Kaul, A. Vavilov, V. 
Vysotsky, S. Fetisov, Development and 
production of second generation high Tc 
superconducting tapes at SuperOx and 


 rst tests of model cables, Supercond. 

Sci. Technol. 27 (2014) 044022.

 .S. Vysotsky, S.Yu. Zanegin, V.V. 

Zubko, A.A. Nosov, G.G. Svalov, S.S. 
Fetisov, S.R. Lee, S.V. Samoylenkov, 
First models of current-carrying 
conductors of superconductive cables 
manufactured with the use of Russian 
second-generation HTS tapes and 
results of their tests, Cables and 
Conductors, 2013, 

 6, p. 26. 


Fig. 5. Components of an HVDC link 

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Moscow energy system supplies power to consumers in the territory of Moscow City and Moscow Region, with the total area of 47 000 m2 and population of over 19 million people.


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