Electrical Power and Energy Systems 29 (2007) 191–198
www.elsevier.com/locate/ijepes
Comparison of magnetically controlled reactor (MCR) and
thyristor controlled reactor (TCR) from harmonics point of view
R.R. Karymov *, M. Ebadian
Moscow Power Engineering Institute, St. Krasnokazarmennaya 14, 111250 Moscow, Russian Federation
Received 13 October 2005; accepted 15 June 2006
Abstract
Shunt reactors are used to compensate for the effects of line capacitance, particularly to limit voltage rise on open circuit or small load.
Magnetically controlled reactor (MCR) is a device in which DC pulsing through a special winding controls inductive susceptance.
MCR has a high saturation of the magnetic circuit with optimal magnetic and electrical circuit parameters that ensures less than 2–
3% main harmonic distortion even without special filters operation.
In this paper, comparison of MCR and TCR from the point of view of harmonics, is studied. A detailed model of reactor is used to
illustrate the ideas presented throughout the paper.
Ó 2006 Published by Elsevier Ltd.
Keywords: Magnetically controlled reactor; Thyristor controlled reactor
1. Introduction
The MCR is controlled by changing magnetic permeability of the core. Magnetization of the steel is being controlled by DC in control windings of the reactor thus
achieving magnetic biasing of the steel. MCR is based on
two original principles:
A thyristor controlled reactor (TCR) is one of the simplest FACTS elements. It consists of a linear reactor in series with two bipolar thyristors. Changing the current by
triggering the thyristors affects the apparent susceptance,
i.e. the apparent susceptance of the TCR is a function of
thyristor firing angle [2].
2. Magnetically controlled reactors (MCR)
(1) The first principle of the MCR is generation and control of the direct component of the magnetic flux in
the MCR two cores by periodic shorting of some of
the reactor winding turns by the use of semiconductor
switches.
(2) The second principle of the MCR is profound magnetic saturation of the two cores under rated conditions, when the saturation magnetization generated
by the direct component of the magnetic flux is
achieved over about half or more of the grid-frequency period [1].
*
Corresponding author.
0142-0615/$ - see front matter Ó 2006 Published by Elsevier Ltd.
doi:10.1016/j.ijepes.2006.07.002
The elementary controlled inductance is represented in
Fig. 1 [3].
The winding w1 is included in a circuit of an alternating
current i and winding of control, w2 joined to source of
DC.
If / = /m sin xt and / = f(Hl) , then for each value xt
by means of curve / = f(Hl) we find appropriate values
H1 and build a curve, iw1 + Iw2 = f(xt).
Fig. 2a, shows magnetic flux and current, when I = 0,
and in Fig. 2b, when I 5 0.
The line A1–A2 in Fig. 2b, would be a zero line for curve
iw1 = f(xt). The current i changes about this straight line
such that average current for the period from xt = 0 up
to xt = 2p is equal to zero.
192
R.R. Karymov, M. Ebadian / Electrical Power and Energy Systems 29 (2007) 191–198
3. The basic electrical circuits of MCR
i
V
W1
W2
R
I
E
Fig. 1. The elementary controlled inductance.
φ
φ
Iwo = 0
φm sin ω t
a2
φ = f (Hl )
a1
b1
Hl = iw1 + Iw 0
a3
4. The model of MCR
Single-line connection of three-phase reactor, 180 MVA,
500 kV is shown in Fig. 5.
1. Three-phase group of single-phase 60 MVA, 500 kV
MCR (CO in Fig. 6a).
iw1 = f (ω t)
b3
The basic electrical circuits of magnetically controlled
reactors are shown in Fig. 3 [1].
The basic idealized circuit of connection of windings of
two cores, single-phase coincides with one of the widespread circuits of magnetic amplifiers (Fig. 3). There are
two closed magnetic circuits, each of which is covered with
a half of each winding – CO and OY.
The parts of OY are connected consistently, current in
one, with current in windings of CO, same direction and
in another the opposite direction (Fig. 3).
Fig. 4 shows current in CO windings, at the voltage
source E in OY windings.
Under normal conditions (E = 0), the MCR is not saturated. With increase in voltage E, the current of MCR, i in
winding w1 (Fig. 1), increases from zero to maximum, the
reactive power consumed in reactor also increases.
Let us pay attention to the current i that does not contain a constant component as in a circuit of winding w1
there is no source of DC. The current is essentially reactive
and sinusoidal.
b2
V
ωt
Fig. 2a. Magnetic flux and current, when I = 0.
i
CO
i
φ
φm sin ω t + φo
φ
φ = f ( Hl )
Iwo ≠ 0
I
b1
c1
a1
φo
I
OY
E
e1
A1
d1
a2
Hl = iw1 + Iw0
Fig. 3. The basic electrical circuits of MCR.
b2
c2
iw1 = f (ω t)
d2
e2
Iwo
ωt
A2
Fig. 2b. Magnetic flux and current, when I 5 0.
Fig. 4. Current in CO windings, at the voltage source E in OY windings.
ID
400278
Title
Comparisonofmagneticallycontrolledreactor(MCR)andthyristorcontrolledreactor(TCR)from
harmonicspointofview
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Pages
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