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Materials Today: Proceedings XX (2016) XXX–XXX
www.materialstoday.com/proceedings
PMME 2016
A Variable Structured TCSC Controller for Power System Stability
Enhancement
Bibhu Prasad Ganthiaa*, Aditi Abhisiktab, Deepanwita Pradhanc, Anwes Pradhand
a
Department of Electrical Engineering, Indira Gandhi Institute of Technology, Sarang, Dhenkanal, India
b
Department of Electrical Engineering, VSSUT, Burla, India
c
Department of Electrical Engineering, National Institute of Technology, Rourkela, India
d
Department of Industrial Management, College of Engineering & Technology, Bhubaneswar, India
Abstract
In present era, the main contact of the power segment engineers is to expand the ability and immovability of the current power segment for
attractive system presentation and dependable process. This directs to the growth of FACTS technology. FACTS controllers raise power convey
ability and constancy. This article represents representing and simulation of single machine infinite bus (SMIB) system with TCSC
controller. Thyristor Controlled Series Capacitor (TCSC) controller is exercised to improve transient constancy of the SMIB system. In this
article propose of TCSC controller is projected. The form of SMIB with TCSC and PID controllers are expanded in MATLAB for simulation.
Three phase symmetrical faults are initiated to learn its characteristics. The simulation effects confirm that the constancy of the power
system is being developed by TCSC controller and it efficiently damp out the power system oscillations.
© 2016 Elsevier Ltd. All rights reserved.
Selection and Peer-review under responsibility of International Conference on Processing of Materials, Minerals and Energy (July 29th – 30th)
2016, Ongole, Andhra Pradesh, India.
Keywords: Stability enhancement; FACTS; TCSC; VAR
1. Introduction
At present, power systems are expanding in apply and difficulty, are precised by long distance huge power transmissions and
large region similarity. To gratify reliability, load demand and stability criteria in a compound present interrelated power system,
either it is wanted to operate the presented transmission lines more powerfully, or recently created lines should be connected to
the system. When the raise of electrical power require, the power stations are slightly situated in detached areas. As a result, it has
become unavoidable to create innovative long transmission lines and by latest technologies. Alternatively, this idea is very
exclusive and ecological matters should be believed. One of the resolutions to this trouble is the operation of the accessible
transmission lines further efficiently and with a higher loading capacity. To recognize a elegant and fault liberal grid a
new technology Flexible AC transmission system (FACTS) was suggested. FACTS devices are mainly solid state converters
having the capability of scheming different electrical parameters in transmission circuits line. The instruments of FACTS family
i.e. Thyristor Controlled Series Compensator (TCSC), Static VAR Compensator (SVC), Static Synchronous Series Compensator
(SSSC), Static Compensator (STATCOM), Unified Power Flow Controller (UPFC),Thyristor Controlled Phase Angle Regulator
(TCPST) etc.

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike License, which permits non-commercial
use, distribution, and reproduction in any medium, provided the original author and source are credited.
* Corresponding author. Tel.: +91-9439618046.
E-mail address: jb.bibhu@gmail.com
2214-7853 © 2016 Elsevier Ltd. All rights reserved.
Selection and Peer-review under responsibility of International Conference on Processing of Materials, Minerals and Energy (July 29th – 30th) 2016, Ongole,
Andhra Pradesh, India.
Bibhu Prasad Ganthia/ Materials Today: Proceedings XX (2016) XXX–XXX2
At present the stability of power system has been become a chief anxiety in structure process. Numerous disorders absorb
a large digression of generator rotor angles, bus voltages, power flows and other system variables. In present days significant
labors have been made to progress or improve the power system stability. To convene the load demand in a complex intersected
power system and gratify the stability and reliability criteria in current power systems with EHV, operation of the accessible
transmission lines more effectively and have higher loading capacity is the best solution. So to diminish power oscillations
through a disorder and to develop power system stability FACT devices can be applied in transmission line. In this learn TCSC
controller with various managed configuration is proposed individually to progress the presentation of power system issued to a
disorder.
2. Basic Module of TCSC
TCSC is one of the mainly significant and greatest identified series FACTS controllers. It has been in exercise for many years to
raise line power reassign in addition to develop system stability. Mostly a TCSC abides of three mechanisms; capacitor banks C,
bypass inductor L and bidirectional thyristors. The firing angles of the thyristors are managed to regulate the TCSC reactance in
agreement with a system control algorithm, usually in reply to some system parameter deviations. According to the
deviation of the thyristor firing angle () or conduction angle (), this practice can be formed as a quick change between
equivalent reactance presented to the power system. Assuming that the total current exceeding during the TCSC is sinusoidal;
the corresponding reactance at the fundamental frequency can be presented as a variable reactance XTCSC. There survives a
steady-state relationship between  and the reactance XTCSC. This relationship can be explained by the subsequent equation:
where,
XC = Nominal reactance of the fixed capacitor (C).
X P = Inductive reactance of inductor (L) connected in parallel with (C).
  2(   ) , the conduction angle of TCSC controller.
k The compensation ratio
While the relationship between α and the corresponding fundamental frequency reactance proposed by TCSC, XTCSC
() is an exclusive-significance function; the TCSC is copied here as variable capacitive reactance within the effective section
distinct by the restrictions forced by α. Thus XTCSCmin ≤ XTCSC ≤ XTCSCmax, with XTCSCmax = XTCSC (αmin) and
0
XTCSCmin= XTCSC(180 ) = XC. This paper depicts the controller is supposed to control only in the capacitive area, i.e., αmin >
0
αr where αr communicates to the significant point, as the inductive section connected with 90 < α < αr encourages high
harmonics that cannot be correctly formed in stability exercises.
Fig.1. Basic Module of TCSC
3. SMIB Power System with TCSC
The SMIB power system with TCSC (viewed in Fig. 2), is judged in this learn. The generator has a limited load of admittance Y =
G + jB and impedance of the transmission line is Z = R + jX. VT and VB are the generator terminal and infinite bus voltage
correspondingly. The generator is presented by the third-order form involving of the generator internal voltage equation and
electromechanical swing equation. The state equations may be written as:
Bibhu Prasad Ganthia/ Materials Today: Proceedings XX (2016) XXX–XXX3
  Pm  Pe  D(   1 ) M (2)
  b(   1 )
(3)
VT  vd  jvq
(4)
I  id  jiq
(5)
where, Pm and Pe are the input and output powers of the generator correspondingly; M and D are the inertia constant and
damping coefficient correspondingly; ωb is the synchronous speed; VT is the terminal voltage; I is the current,
rotor angle and speed correspondingly.

and

are the
Fig.2. Single-machine infinite-bus power system with TCSC
4. Design Modelling of TCSC Dynamics
The frequently applied lead–lag construction is selected in this learn as a TCSC controller. The construction of the TCSC
controller is viewed in Fig. 3. It contains a gain block with gain KP, two-stage phase compensation block and a signal block. The
phase compensation block offers the suitable phase-lead features to balance for the phase lag between input and the output signals
where signal block (washout) provides as a high-pass filter, with the time constant TW, high adequate to permit signals connected
with oscillations in input signal to exceed unchanged. Without it steady modifies in input would change the output. From the
point of view of the washout function the value of TW is not significant and may be in the range 1 to 20 seconds.  0 is the first
conduction angle as required by the power flow control loop. The power flow control loop performs renounce slowly in exercise
and therefore  0 stay stable throughout large-disorder transient time.
Fig.3. Structure of TCSC controller
Fig.4. SMIB Power system with TCSC
This paper spotlights awareness on the single machine infinite bus (SMIB) power systems. Because SMIB system is virtually easy
to learn, it is really helpful in relating the common ideas of power system stability, the power of different features ahead stability,
and another controller idea. The SMIB mounted with TCSC is viewed in figure 4. Vt and Eb are the generator terminal and infinite
bus voltage correspondingly. XT, XL and XTH signify the reactance of the transformer and also signify transmission line per
circuit and the Thevenin‟s impedance of the receiving end system correspondingly.
5. Structure of the TCSC-Based Controller
Fig.5. Lag-Lead Structure of TCSC based Controller
Fig.6. PID Structure of TCSC based Controller
Bibhu Prasad Ganthia/ Materials Today: Proceedings XX (2016) XXX–XXX4
Fig.7. Variable Structured TCSC based Controller
6. Matlab/Simulink Models
Fig.8. SIMULINK Model of SIMB with TCSC controller
Fig.9. SIMULINK model for calculation of id, iq, Ed, Eq and Pe
7. Simulation Results
7.1 Lead-Lag Controller
Case-1: Three-phase Fault Disturbance
Fig.10. Variation of power angle δ, without and with TCSC controller
Fig.11. Variation of speed deviation ∆ω
Bibhu Prasad Ganthia/ Materials Today: Proceedings XX (2016) XXX–XXX5
Fig.12. Variation of electrical power
Fig.18. Variation of speed deviation ∆ω
Fig.13 Variation of Xtcsc
7.2 Lead-lag Controller:
Case-2: Line outage Disturbance
Fig.19. Variation of electrical power
Fig.20. Variation of Xtcsc
Fig.14 Variation of δ
7.4 PID Controller:
Case-1: nominal loading, Three-phase Fault Disturbance
Fig.15 Variation of speed deviation ∆ω
Fig.21. Variation of power angle δ
Fig.16.Variation of electrical power
7.3 Lead-lag Controller:
Case3: Small Disturbance
Fig.17. Variation of δ
Fig.22. Variation of speed deviation ∆ω
Fig.23. Variation of Xtcsc
Bibhu Prasad Ganthia/ Materials Today: Proceedings XX (2016) XXX–XXX6
7.5 PID Controller:
Case-2: nominal loading, permanent line outage
Fig.29. Variation of Xtcsc
Fig.24. Variation of power angle δ
7.6 PID Controller:
Case-2: nominal loading, permanent line outage disturbance
7.8 PID Controller:
Case-4: heavy loading, small disturbance
Fig.25. Variation of speed deviation ∆ω
Fig.30. Variation of power angle δ
Fig.26. Variation of Xtcsc
Fig.31. Variation of speed deviation ∆ω
7.7 PID Controller:
Case-3: light loading, temporary line outage disturbance
Fig.32. Variation of Xtcsc
Fig.27. Variation of power angle δ
Fig.28. Variation of speed deviation ∆ω
7.9 Variable Structure Controller TCSC
Case-5: TCSC application
Fig.33. Variation of power angle δ
Bibhu Prasad Ganthia/ Materials Today: Proceedings XX (2016) XXX–XXX7
8. Conclusion
The MATLAB/SIMULINK model of a single-machine infinite-bus power system with a TCSC controller with both lead-lag &
PID construction is represented and the realisation of the preferred controllers is verified under distinct disorders. A short
contention of variable constructed TCSC controller is offered and it is physically checked in huge disorder for rotor angle
oscillation damping. Simulation results explain that the cause of TCSC controller in the analysis power system moist out the
oscillations quicker than when controller is not represent in the power system bears dissimilar disorder.
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