ISSN:
2181-3906
2024
International scientific journal
«MODERN SCIENCE АND RESEARCH»
VOLUME 3 / ISSUE 12 / UIF:8.2 / MODERNSCIENCE.UZ
758
FEATURES OF OPERATING MODES OF SYNCHRONOUS AND STATIC
COMPENSATORS
A.Y.Bekishev
1
,
SH.B.Korjovov
1
1
Tashkent State Technical University named after Islam Karimov, 100095, Uzbekistan,
Tashkent, University St. 2A.
Gmail:
https://doi.org/10.5281/zenodo.14555928
Abstract.
The article presents the features of the operating modes of synchronous and static
compensators. The purpose of the article is to provide students, undergraduates and graduate
students with new material on new domestic microprocessor-based integrated automatic devices
and systems, to promote advanced training of personnel at power plants and electric power
systems and to introduce into operation microprocessor-based automation equipment and relay
protection of electric power systems in the process of its modern updating.
Keywords:
microprocessor-based integrated automatic devices, power plants, electric
power systems, microprocessor technologies, automation equipment.
ОСОБЕННОСТИ РЕЖИМОВ РАБОТЫ СИНХРОННЫХ И СТАТИЧЕСКИХ
КОМПЕНСАТОРОВ
Аннотация.
В статье представлены особенности режимов работы синхронных и
статических компенсаторов. Цель статьи — обеспечить студентов, магистрантов и
аспирантов новым материалом по новым отечественным микропроцессорным
комплексным автоматическим устройствам и системам, способствовать повышению
квалификации кадров на электростанциях и в электроэнергетических системах и
внедрению в эксплуатацию микропроцессорных средств автоматизации и релейной
защиты электроэнергетических систем в процессе их современного обновления.
Ключевые слова:
микропроцессорные комплексные автоматические устройства,
электростанции, электроэнергетические системы, микропроцессорные технологии,
средства автоматизации.
INTRODUCTION.
Modern high-and ultra-high-voltage power transmission lines are powerful uncontrolled
generators of reactive power when the transmitted active power P
l
is less than natural P
nat
, or
consumers - when P
l
>P
nat
. Therefore, traditional modern reactive power generators - synchronous
compensators function as controlled reversible sources, i.e. and as its consumers.
New reactor (consuming) and reactor-capacitor (reversing) static reactive power
compensators, designed for connection to the buses of power stations and intermediate node
substations of main power transmission lines, have been created and continue to be developed.
Results and Discussion.
A synchronous compensator is used in modern EPS not only as a
generator of reactive power, but also as its controlled consumer. The generation (output) or
consumption mode is determined by the excitation of the synchronous compensator.
In accordance with its U-shaped characteristic (Fig. 1, a) at the rated excitation current
I
ex.nom
, the synchronous compensator produces reactive power
ISSN:
2181-3906
2024
International scientific journal
«MODERN SCIENCE АND RESEARCH»
VOLUME 3 / ISSUE 12 / UIF:8.2 / MODERNSCIENCE.UZ
759
d
B
nom
q
B
nom
SK
x
U
E
U
Q
/
.
.
(1)
and in the absence of excitation (I
ex
=0) - consumes reactive power
nom
SK
d
B
SK
Q
x
U
Q
.
2
0
5
,
0
(2)
The highest possible load of the synchronous compensator with consumed reactive power
is achieved either with a marginal negative excitation current, or in the absence of excitation Iв=0
and the internal angle of the compensator δ=π/2 (Fig. 1, c), i.e. when the rotor is located along the
transverse axis. Wherein
nom
SK
d
B
br
SK
Q
x
U
Q
,
2
.
75
,
0
(3)
The boundary mode of reactive power consumption is determined by the condition for the
stability of the synchronous compensator - maintaining synchronism. The synchronizing torque is
generated by a synchronous electromagnetic
S
M
and reactive (due to salient polarity)
R
M
moments
.
2
sin
2
;
sin
2
q
d
q
d
B
R
d
B
q
S
x
x
x
x
U
M
x
U
E
M
(4)
In particular, in the absence of excitation, the synchronous compensator is kept in
synchronism only due to the reactive torque. With negative excitation, the synchronous torque
counteracts the reactive torque and impairs the stability of the synchronous compensator.
ISSN:
2181-3906
2024
International scientific journal
«MODERN SCIENCE АND RESEARCH»
VOLUME 3 / ISSUE 12 / UIF:8.2 / MODERNSCIENCE.UZ
760
Fig. 1. Graphs of the dependences of reactive power on the excitation current (a) torque (b)
and consumed reactive power (c) on the internal angle of the synchronous compensator
Limit value of negative EMF
br
q
E
.
is determined by setting the derivative of the
synchronizing torque with respect to the angle δ to zero. Taking into account (4)
,
0
2
cos
cos
2
.
q
d
q
d
B
d
B
br
q
R
S
x
x
x
x
U
x
U
E
M
M
d
d
(5)
at δ=0
.
.
q
B
q
q
d
B
br
q
x
x
U
x
x
x
U
E
(6)
With negative excitation, the highest reactive power consumption is
br
SK
Q
.
theoretically
achieved in the boundary mode at δ=0. In practice, due to the presence of active power losses (for
ventilation, friction), the power
br
SK
Q
.
is achieved at angle δ≈π/10.
In boundary mode, the synchronous compensator falls out of synchronism. According to
(4) and Fig. (1, b) at δ=π/4
,
max
.
R
br
S
M
M
(7)
and at δ>π/4 the synchronizing torque is negative. Even in the absence of negative
excitation, the angle δ>π/4 increases as the reactive torque decreases. At δ=π/2, i.e. when the rotor
is positioned along the transverse axis, the stator resistance is equal to
q
x
and the power
consumption reaches close to the highest value (3) in the absence of excitation (I
ex
=0). But such a
mode is possible only under conditions of artificial stability of the synchronous compensator.
The possibility of continuous control of the power of reactors and discrete changes in the
power of capacitor units by powerful thyristor controlled devices and thyristor switches,
respectively, led to the development of reversible controlled static compensators (STC), more
reliable, fast-acting and less expensive than rotating synchronous compensators. In connection
with the revealed features of switching sectionalized capacitor units, it turned out to be advisable
to carry out STC consisting of a continuously controlled reactor part and a permanently switched
on or only switched on and off capacitor unit as a whole. Since continuously controlled reactor
STCs generate harmonic components of voltage and current in modes of low load of consumed
reactive power (at large switching angles of thyristors π/2<α<2π/3), it was necessary to section
them and carry out discrete-continuous control of their power, i.e. . switch on and off individual
reactors with continuously varying power of each of them using thyristor converters operating with
small thyristor switching angles (π/6<α<π/2). Therefore, two types of STC were defined: both
consist of separate sections (modules), but one with a permanently connected capacitor unit, and
the second with a periodically switched one.
ISSN:
2181-3906
2024
International scientific journal
«MODERN SCIENCE АND RESEARCH»
VOLUME 3 / ISSUE 12 / UIF:8.2 / MODERNSCIENCE.UZ
761
Fig. 2. Scheme of STC reactive power microprocessor system for integrated control and
protection of STC
The first type of STC is partially, and the second is completely reversible. For example,
the control system of one of the substations with a voltage of 1150 kV consists of 14 reactor
continuously controlled modules consuming reactive power up to -1100 Mvar, and a capacitor unit
with a capacity of +300 Mvar. The reversible STC with a power of +55 Mvar contains a
continuously controlled thyristor converter VST (see Fig. 2, a) reactor part LR and a discretely
controlled non-sectional one, i.e. switched on or off, capacitor unit - CB battery with voltage of 10
or 20 kV [3].
Synchronous electric motors also serve as compensators for consumed reactive power (its
generators). However, they practically cannot work in the reactive power consumption mode.
CONCLUSION
1.
The highest possible load of the synchronous compensator with consumed reactive power
is achieved either with a marginal negative excitation current, or in the absence of excitation I
ex
=0
and the internal angle of the compensator δ=π/2, that is when the rotor is located along the
transverse axis.
2.
Since continuously controlled reactor STCs in low load modes of consumed reactive power
(at large switching angles of thyristors π/2 <α< 2π/3) generate harmonic components of voltage
and current, this increases losses in electrical networks.
REFERENCES
1.
Dyakov A.F. Microprocessor automation and relay protection of electrical power systems:
textbook. manual for universities / A.F. Dyakov, N.I. Ovcharenko. - 2nd ed., erased. - M.:
MPEI Publishing House, 2010. - 336 p.
2.
Dyakov A.F., Ovcharenko N.I. Microprocessor relay protection and automation of electrical
power systems: A textbook for university students. M.: MPEI Publishing House, 2000. 199
p.
3.
G.M. Burunova, E.A. Bushmarina, M.A. Lotkov et al. Microprocessor system for automatic
control and protection of a static thyristor compensator for power lines// Automatic control
of electrical power systems: Tr. VEI. M.: Informelektro, 1988. P. 28-34.
ISSN:
2181-3906
2024
International scientific journal
«MODERN SCIENCE АND RESEARCH»
VOLUME 3 / ISSUE 12 / UIF:8.2 / MODERNSCIENCE.UZ
762
4.
Use of Hybrid Renewable Energy
Systems to Excite Autonomous Synchronous Machines.
, 2022,
2432, 020020
5.
Calculation of winding factors and MMFs of rotor windings
of synchronous machines with longitudinal-transversal excitation
Elektrichestvo, 2003, (3),
pp. 68–70
6.
Achievement of
electric energy savings through controlling frequency converter in the operation process of
asynchronous motors in textile enterprises.
IOP Conference Series: Materials Science and
, 2021, 1030(1), 012161
7.
E3S Web of Conferences, 2020, 216, 01120 Frequency control of
asynchronous motors of looms of textile enterprises
8.
Best overall dimensions of synchronous generator with
permanent magnets for small power wind plants and micro hydropower plants. E3S Web of
Conferences, 2019, 139, 01027
9.
Pirmatov N., Bekishev A., S. Shernazarov, N. Kurbanov. E3S Web of Conferences, 2021,
264, 04028,
https://doi.org/10.1051/e3sconf/202126404028
10.
Pirmatov N., Toirov O., Bekishev A., Kurbanov N., Zainieva O., Norkulov N. Conference
Proceedings AIP 2552, 040020 (2023);
https://doi.org/10.1063/5.0115727
11.
Pirmatov N., Bekishev A., Egamov A.AIP Conference Proceedings 2612, 050005
(2023).
https://doi.org/10.1063/5.0135546
12.
Toirov O., Bekishev A., Urakov S., Mirkhonov Yu. E3S Web of Conferences 216, 01116
(2020).
https://doi.org/10.1051/e3sconf/202021601116
13.
N. Pirmatov,A. Bekishev,A. Egamov,S. Shernazarov,F. Isakov,M. Zubaydullayev.
Mathematical modeling of the self-swinging process of synchronous generators. AIP Conf.
Proc. 2612, 050005 (2023).
https://doi.org/10.1063/5.0135546
14.
Beitullaeva, R., Tukhtaev, B., Norboev A., Nimatov, K., &Djuraev, S. (2023). Analysis of
pump operation in common pressure pipelines using the example of the “Chirchik” pumping
station. In E3S Web of Conferences (Vol. 460, p. 08015). EDP Sciences.
15.
Berdiev, U., Norboev A., &Mamarajabova, Z. (2023). Investigation of asymmetry in
asynchronous motor used in a borehole pump. In E3S Web of Conferences (Vol. 383, p.
04057). EDP Sciences.
