This document describes a project to design a three-phase individual controlled fixed capacitor-thyristor controlled reactor (FC-TCR) static VAR compensator (SVC) to perform power factor correction and prevent negative sequence current. It includes an abstract discussing the issues with negative sequence current, an introduction to the FC-TCR SVC design, the design procedure and algorithm, results showing the SVC reduces negative sequence current both with and without power factor correction, the source code implementing the design, and a conclusion stating the SVC approach is effective and unique.
LOAD BALANCING AND POWER FACTOR CORRECTION FOR MULTIPHASE POWERIAEME Publication
In recent years the area of multi-phase (phase order more than three) machines is popular. A multi-phase source may be derived from transformer connection (3- phase to 4-phase) or by DC link 4-phase inverters. There are problem of unbalance, harmonic distortion and poor power factor operation. This paper proposes the supply side load balancing and power factor correction .The proposed compensation scheme uses the shunt current source compensation whose instantaneous values are determined by the instantaneous symmetrical component theory. An ideal compensator in place of physical realization of the compensator has been proposed in form of a current controlled voltage source inverter. The compensation schemes developed in the paper are tested for their validity on 4-phase (4-wire & 5-wire) circuits through extensive simulations.
Control of Active And reactive power flow in transmission line and power Osci...AM Publications
the continuous demand in electric power system network has caused the system to be heavily loaded
leading to voltage instability. This paper describe the active approach to series line compensation, in which static
voltage sourced converter, is used to provide controllable series compensation. This compensator is called as Static
synchronous series compensator (SSSC). It injects the compensating voltage in phase quadrature with line current, it
can emulate as inductive or capacitive reactance so as to influence the power flow in the line. With DC power supply it
can also compensate the voltage drop across the resistive component of the line impedance. In addition, the series
reactive compensation can greatly increase the power oscillation damping.
Simulations have been done in MATLAB SIMULINK. Simulation results obtained for selected bus-2 in two machine
power system. From the result we can investigate the effect of this device in controlling active and reactive power as
well as damping power system oscillations in transient mode.
LOAD BALANCING AND POWER FACTOR CORRECTION FOR MULTIPHASE POWERIAEME Publication
In recent years the area of multi-phase (phase order more than three) machines is popular. A multi-phase source may be derived from transformer connection (3- phase to 4-phase) or by DC link 4-phase inverters. There are problem of unbalance, harmonic distortion and poor power factor operation. This paper proposes the supply side load balancing and power factor correction .The proposed compensation scheme uses the shunt current source compensation whose instantaneous values are determined by the instantaneous symmetrical component theory. An ideal compensator in place of physical realization of the compensator has been proposed in form of a current controlled voltage source inverter. The compensation schemes developed in the paper are tested for their validity on 4-phase (4-wire & 5-wire) circuits through extensive simulations.
Control of Active And reactive power flow in transmission line and power Osci...AM Publications
the continuous demand in electric power system network has caused the system to be heavily loaded
leading to voltage instability. This paper describe the active approach to series line compensation, in which static
voltage sourced converter, is used to provide controllable series compensation. This compensator is called as Static
synchronous series compensator (SSSC). It injects the compensating voltage in phase quadrature with line current, it
can emulate as inductive or capacitive reactance so as to influence the power flow in the line. With DC power supply it
can also compensate the voltage drop across the resistive component of the line impedance. In addition, the series
reactive compensation can greatly increase the power oscillation damping.
Simulations have been done in MATLAB SIMULINK. Simulation results obtained for selected bus-2 in two machine
power system. From the result we can investigate the effect of this device in controlling active and reactive power as
well as damping power system oscillations in transient mode.
Application of Capacitors to Distribution System and Voltage RegulationAmeen San
Application of Capacitors to
Distribution System and Voltage
Regulation
POWER FACTOR IMPROVEMENT,
System Harmonics
Voltage Regulation
Methods of Voltage Control
In electrical engineering, a synchronous condenser (sometimes synchronous capacitor or synchronous compensator) is a device identical to a synchronous motor, whose shaft is not connected to anything but spins freely.
giving details of reactive power compensation in simple way and the study we had and on base of it d capacitor we designed... and some references are also there to get more details of reactive power and its compensation
Analyses of reactive power compensation schemes in MV/LV Networks with RE infeedAushiq Ali Memon
-Reactive power compensation in MV/LV Networks
-Voltage control with renewable energy infeed
- Power factor correction with reactive power compensation schemes (SVC and STATCOM)
-DFIG wind turbine grid-code requirements according to bdew standard.
Soft power factor modification using staticchodachude
A good power quality at a system can optimize the efficiency of electrical energy utilization.
Comparison of active power and apparent power will produce a power factor (COS ø).Capacitors bank can
maintain optimum power factor with compensating some reactive power to the system. Static VAR
Compensator (SVC) is generally composed of a conventional capacitor bank in parallel with the load contactor
switch. This leads to a very large inrush current to the capacitor which will resulting damage to the
contactor switches and also capacitors. To reduce inrush current, thyristor is used as a replacement of
contactor switch. Switch can be set by adjusting the firing angle of thyristor. Power factor improvement consists
of a voltage sensor, current sensor, zero crossing detector, thyristor driver and the capacitor bank. The existing
load on the system consists of induction motor 125W, rectifier with load of series of incandescent lamp with
ballasts 85W and fluorescent lamp 20W.Cos phi variation of the load is 0.49 (lag), 0.99 (lag), 0.92 (lag) and 0.62
(lag) when all the loads connect to the system. Through the calculation, the value of capacitor that can
compensate the reactive power to the system is 5.12 µF, 2.71 µF, 2.41 µF and 9.55µF. The capacitor
installation obtain good response because it can increase the cos phi of system to 0.99 (lag) and the current
consumption of the system is smaller than the pre-installation of capacitors, which can reduce the line system
current up to 30% of the system current
Application of Capacitors to Distribution System and Voltage RegulationAmeen San
Application of Capacitors to
Distribution System and Voltage
Regulation
POWER FACTOR IMPROVEMENT,
System Harmonics
Voltage Regulation
Methods of Voltage Control
In electrical engineering, a synchronous condenser (sometimes synchronous capacitor or synchronous compensator) is a device identical to a synchronous motor, whose shaft is not connected to anything but spins freely.
giving details of reactive power compensation in simple way and the study we had and on base of it d capacitor we designed... and some references are also there to get more details of reactive power and its compensation
Analyses of reactive power compensation schemes in MV/LV Networks with RE infeedAushiq Ali Memon
-Reactive power compensation in MV/LV Networks
-Voltage control with renewable energy infeed
- Power factor correction with reactive power compensation schemes (SVC and STATCOM)
-DFIG wind turbine grid-code requirements according to bdew standard.
Soft power factor modification using staticchodachude
A good power quality at a system can optimize the efficiency of electrical energy utilization.
Comparison of active power and apparent power will produce a power factor (COS ø).Capacitors bank can
maintain optimum power factor with compensating some reactive power to the system. Static VAR
Compensator (SVC) is generally composed of a conventional capacitor bank in parallel with the load contactor
switch. This leads to a very large inrush current to the capacitor which will resulting damage to the
contactor switches and also capacitors. To reduce inrush current, thyristor is used as a replacement of
contactor switch. Switch can be set by adjusting the firing angle of thyristor. Power factor improvement consists
of a voltage sensor, current sensor, zero crossing detector, thyristor driver and the capacitor bank. The existing
load on the system consists of induction motor 125W, rectifier with load of series of incandescent lamp with
ballasts 85W and fluorescent lamp 20W.Cos phi variation of the load is 0.49 (lag), 0.99 (lag), 0.92 (lag) and 0.62
(lag) when all the loads connect to the system. Through the calculation, the value of capacitor that can
compensate the reactive power to the system is 5.12 µF, 2.71 µF, 2.41 µF and 9.55µF. The capacitor
installation obtain good response because it can increase the cos phi of system to 0.99 (lag) and the current
consumption of the system is smaller than the pre-installation of capacitors, which can reduce the line system
current up to 30% of the system current
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Micro-controller based Automatic Power Factor Correction System ReportTheory to Practical
This project report represents one of the most effective automatic power factor improvements by using static capacitors which will be controlled by a Microcontroller with very low cost although many existing systems are present which are expensive and difficult to manufacture. In this study, many small rating capacitors are connected in parallel and a reference power factor is set as standard value into the microcontroller IC. Suitable number of static capacitors is automatically connected according to the instruction of the microcontroller to improve the power factor close to unity. Some tricks such as using resistors instead of potential transformer and using one of the most low cost microcontroller IC (ATmega8) which also reduce programming complexity that make it one of the most economical system than any other controlling system.
FIRING ANGLE SVC MODEL FOR ANALYZING THE PERFORMANCE OF TRANSMISSION NETWORK ...IAEME Publication
This paper deals with Power flow, which is necessary for any power system solution and carry
out a comprehensive study of the Newton- Raphson method of power flow analysis with and without
SVC. Voltage stability analysis is the major concern in order to operate any power system as
secured. This paper presents the investigation on N-R power flow enhancement of voltage stability
and power loss minimization with & without FACTS controllers such as Static Var Compensator
(SVC) device. The Static Var Compensator (SVC) provides a promising means to control power
flow in modern power systems. In this paper the Newton-Raphson is used to investigate its effect on
voltage profile and power system lossess with and without SVC in power system.. Simulations
investigate the effect of voltage magnitude and angle with and without SVC on the power flow of
the system. This survey article will be very much useful to the researchers for finding out the
relevant references in the field of Newton-Raphson power flow control with SVC in power systems.
In order to reach the above goals, these devices must be located optimally. In this paper the
Optimal placement of SVC is carried out by Voltage collapse Prediction Index (VCPI).The size of
the SVC is determined by suitable firing angle which reduces the losses in the system. Simulations
have been implemented in MATLAB Software and the IEEE 14 and IEEE 57-bus systems have been
used as case studies.
An Experimental Study of the Unbalance Compensation by Voltage Source Inverte...IJPEDS-IAES
This work presents an experimental study of the unbalance compensation
caused by the high speed railway substations in the high-voltage power grid
with a shunt voltage source inverter based STATCOM. This experimental
study is realized on a reduced scale prototype. The Control of inverter is
implemented in a DSP card. The practical results presented in this paper are
shown the performance of unbalance compensation by VSI_STATCOM in
static and dynamic regime.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
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yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
FC/PV Fed SAF with Fuzzy Logic Control for Power Quality EnhancementIJPEDS-IAES
In this paper, a Fuel cell (FC)/Photovoltaic cell (PV)/Battery operated three- phase Shunt Active power Filter (SAF) is proposed for improving the power quality at the utility side. Fuzzy based instantaneous p-q theory control is proposed for SAF. This SAF consists of Voltage Source PWM Converter (VSC) and a DC link capacitor supplied by a FC/PV/Battery. The filter provides harmonic mitigation with reactive power compensation and neutral compensation for loads at the Point of Common Coupling (PCC). A Single switch boost DC-DC converter connects the FC/PV/Battery with the VSC to maintain the load. The performance of the proposed SAF is tested in MATLAB/SIMULINK environment with Fuzzy logic controller (FLC). The controller maintains the DC link voltage based on the current reference generated by the p-q theory. The Hysteresis PWM current controller is employed to generate the gating pulses to the switches in VSC. The simulation results of the proposed SAF validate the effectiveness of FLC in power quality enhancement.
AN ACTIVE POWER CONTROL STRATEGY FOR HYBRID MICRO-HYDRO AND PHOTOVOLTAIC MICR...Shristi Shrestha
This is the final defense presentation by me and my project team on An Active Power Control Strategy for Hybrid Micro-hydro and Photovoltaic Microgrid Using Battery Energy Storage System (BESS).
Improvement of power quality has to be treated as a matter of at most importance in the open
market economy due to the increased use of non linear loads. Several devices have been used to mitigate
the power quality problems. Now a days researchers are concentrating on the use of FACT devices to
overcome power quality issues. Unified Power Quality Conditioner is one among such FACT devices upon
which this paper has concentrated for mitigating the Power Quality problems. Here a 3 phase 3 wire
UPQC is realised using MATLAB/SIMULINK to mitigate voltage sag and swell as well as to maintain
sinusoidal voltage and current at PCC irrespective of load dynamics.
Modified Bidirectional Converter with Current Fed InverterIJPEDS-IAES
A bidirectional dc-dc converter with multiple outputs are concatenated with a
high frequency current source parallel resonant push pull inverter is
presented in this paper. The two outputs are added together and it is taken as
the input source for the inverter. The current source parallel resonant push
pull inverter implemented here with high frequency applications like
induction heating, Fluorescent lighting, Digital signal processing sonar. This
paper proposes a simple photovoltaic power system consists of a
bidirectional converter and a current fed inverter for regulating the load
variations. Solar power is used as the input source for the system. Simulation
of the proposed system is carried out in PSIM software and experimentally
verified the results.
Improvement In Pre-Regulation For Power Factor Using CUK ConverterIJRES Journal
Cuk converters, operating in Discontinuous Capacitor Voltage Mode can achieve unity power factor when used as rectifiers with no need of duty-cycle modulation. This operating mode causes high voltage stresses across the semiconductors, calling for high-voltage switches like IGBT's. However, zero-voltage turn-off is achieved, resulting in limited power loss even at high frequency. Both current- and voltage-fed approaches as well as constant- and variable-frequency control are analyzed in the paper. Simulation and experimental results are Explained, which demonstrate actual converter performance. Most of the power factor regulator topologies in continuous conduction mode result in bulky magnetic, and in discontinuous conduction mode result in high harmonic content. To solve these problems a Cuk topology is presented in discontinuous conduction mode with coupled inductors for power factor regulation, the unique feature exhibited by the converter that makes the converter better than the other converter in operation for power factor regulation. Inductive coupling is used to transfer the ripple from the input to the output side thereby reducing the switching harmonics in the line current. Experimental results obtained on a some Watt prototype are also presented.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Power factor improvement is the essence of any power sector for realible operations. This report provides literature study of a fixed capacitor thyristor controlled reactor type of power factor compensator by matlab simulation and implementation in programmed microcontroller. To retaining power factor closed to unity under various load condition the arduino ATmega8 microcontroller is used which is programmed by keil software. The simulation is done using proteus software which display power factor according to the variation in load whenever a capacitive load is connected to the transmission line, a shunt reactor is connected which injects lagging reactive VARs to the power system. This report also includes the matlab simulation for three phase power factor improvement by using fixed capacitor thyristor controlled reactor. As a
result the power factor is improved. The results given in this report provides
suitable matlab simulation and proteus simulation based reactor power compensation and power factor improvement and techniques using a FCTCR.
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ARENA - Young adults in the workplace (Knight Moves).pdfKnight Moves
Presentations of Bavo Raeymaekers (Project lead youth unemployment at the City of Antwerp), Suzan Martens (Service designer at Knight Moves) and Adriaan De Keersmaeker (Community manager at Talk to C)
during the 'Arena • Young adults in the workplace' conference hosted by Knight Moves.
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Design of a 3-phase FC-TCR Static Var Compensator for Power factor correction and Preventation of negative sequence current
1. 1 | P a g e
COURSE: EE 5374
COURSE TITLE: POWER SYSTEMS PROTECTIVE RELAYING
INSTRUCTER: DR.W.J.LEE
TERM: SPRING‐2015
NAME: HARDIK PARIKH
STUDENT ID: 1001090431
SUBJECT: PROJECT-2
Project Title: DESIGN A THREE-PHASE INDIVIDUAL CONTROLLED FIXED
CAPACITOR-THYRISTOR CONTROLLED REACTOR (FC-TCR) STATIC
VAR COMPENSATOR (SVC) TO PERFORM POWER FACTOR
CORRECTION AND PREVENT NEGATIVE SEQUENCE CURRENT
2. 2 | P a g e
Sr.No
INDEX
Subject Page No
1 Abstract 3
2 Introduction 4
3 Design Procedure 5
4 Algorithm 6-7
5 Results 9
6 Source code 10-11
7 Conclusion 12
8 Learning Outcome 12
9 Reference 12
3. 3 | P a g e
Abstract:
In a transmission system, only the positive sequence is usually selected to analyze a
load flow because the power system is assumed to be balanced. In practice,
however, a completely balanced power system is almost impossible to be obtained,
so the zero and negative sequences should exist in the power system. Since a Δ-
Yground connected step-up transformer can block the zero sequence current on
the primary side, the current entering a generator just consists of positive and
negative sequence parts. Beside this negative sequence current produced by the
system heats the windings to possibly damage the generator, it may also cause a
mechanical resonant problem on the generator.
When a system is unbalanced, the frequency of negative sequence current will be
converted into a mechanical vibration frequency through the rotor shaft. This will
create small chronicle damage over the time and results in mechanical failure of
the turbine. As a result we are required adjust the setting of the I2 relay to limit the
negative sequence current going into the generator or to implement methods
which prevent I2 from entering back to generator.
The research has shown that SVC has been proved successful to prevent negative
sequence current more over it also has capabilities for Power factor correction.
• Negative-sequence current causes some problems in generator systems.
Though every generator is capable of withstanding a certain level of
negative-sequence current, excess and/or persistent amounts of negative
sequence current may cause rotor overheating and serious damage.
• Since its frequency quite matches the natural mechanical frequency of
turbine blades and the zero sequence current is blocked by delta connected
step-up transformer, the negative sequence current becomes the only
reason for the super synchronous resonance of a generator due to an
unbalanced system, especially in an isolated power system.
• SVC has the potential to overcome some adverse effects of the negative
sequence current to the turbine generator systems
4. 4 | P a g e
FC-TCR SVC can change the real and reactive power flow and force the output o f
the generator become balanced even though the load is unbalanced. Besides, a
correct and simplified mathematical model which is selected among several
compensating methods would be built up. This model would be easily implemented
in a control program and reduce negative sequence current to the expected value.
Introduction:
To analyze the effects to the whole system when using SVC to reduce the negative
sequence current entering a generator, a three-phase transmission load flow
program has been developed. The connection of an SVC, however, is delta to avoid
producing zero sequence problems; an appropriate delta connected load model for
a load flow program needs to be developed because the load o r shunt reactive
elements used to be in grounded wye. The function of an SVC to reduce the
negative sequence current entering a generator.
Before presenting the special application of a static var compensator system, the
principle of a fixed-capacitor Thyristor Controlled Reactor (FC-TCR) as shown in Fig.
1, is briefly discussed. The adding of the Fixed-Capacitor is to make this SVC also
have the capability of supplying reactive power. The basic elements of the thyristor
controlled reactor, as shown in the right half of Fig. 1, consist of a fixed reactor with
inductance L, and a bidirectional thyristor valve which conducts on alternate half-
cycles. The current flowing through the thyristors can be adjusted from zero to
maximum by controlling the delay angle a.
Fig 1. Basic Elements of a FC-TCR Circuit
5. 5 | P a g e
The fundamental of the negative sequence current reduction on the generator with
SVC is to lead the I
Design procedure:
2 current into the SVC instead of the generator. Beside
generating reactive power; the adjustment o f the firing delay angle o f the SVC can
obtain the unbalanced susceptance to balance the equivalent load impedance,
which connection is delta. The following will compare several different approaches
to reduce generator I2 current with an SVC.
Fig 2. A power system with compensator
Theoretically, a complete compensation can be obtained and the negative
sequence current can be compensated by an SVC.
The Equation can be divided into real and imaginary parts and will have three
variables and two equations. An additional constraint has to be added to obtain a
Unique solution. From the practical point of view, the following constraint is
selected.
8. 8 | P a g e
Available Data:
1. i. The internal voltage of the generator is balanced.
2. ii. The zero sequence current is blocked by using the Δ‐ Y grounded step up
transformer.
3. iii. The magnitude of the phase A voltage is maintained at 1.0pu.
4. iv. The source impedance of the generator is j0.1 pu.
5. v. For simplicity, assume that the SVC is connected at the terminal of the
generator.
6. vi. To avoid the appearances of zero sequence current, the SVC is Δ
connected.
7. vii. The loads are Pa + jQa, Pb+jQb and Pc+jQc.
Procedure:
1. We are provided the phase powers Sa, Sb, Sc.
where Sa = Pa + jQa ; Sb = Pb + j Qb; Sc = Pc + jQc
2. The generator terminal voltage is set at 1.0 pu.
3. We calculate phase currents entering the generator using Ia = (Sa/Va)’
similarly for Ib and Ic and also consider the phase shifts.
4. From these phase currents we calculate the sequence currents I0, I1, I2.
5. Our aim is to reduce the I2 (negative sequence current) as close to zero as
possible.
6. The FC-TCR will generate reactive power Qab, Qbc, Qca and its susceptances
are calculated by dividing the reactive powers by V2
7. Once reactive power from FC-TCR is calculated the total power entering the
generator is calculated using formulas in method 3 of the reference
dissertation.
i.e. generator terminal
voltage.
8. Then the phase and sequence currents are calculated.
9. 9 | P a g e
Results:
Description
Case-I
Without PF Correction
B -1.4989e-006ab
B 1.9535e-007bc
B 1.3036e-006ca
I2 -8.7711e-007 -7.2809e-006isystem
I2 -8.7893e-007 -7.2808e-006isvc
I2 1.8287e-009 -6.1762e-011inet
Case-II
Description With PF Correction
PF = 0.8 PF = 1
B -1.4989e-006ab 0.0999
B 1.9535e-007bc 0.1002
B 1.3036e-006ca 0.0999
K 5.5511e-017 0.3000
I2 -8.7711e-007 -7.2809e-006isystem -8.7711e-007 -7.2809e-006i
I2 -8.7893e-007 -7.2808e-006isvc -9.8327e-004 -8.7025e-006i
I2 1.8287e-009 -6.1762e-011inet 9.8239e-004 +1.4217e-006i
PF New 0.8 1.0
10. 10 | P a g e
Source Code:
%% CASE:1- Without power factor correction
% Load data as provided
Pa= 0.4;
Qa= 0.3;
Sa= Pa+Qa*i;
Pb= 0.4;
Qb= 0.3;
Sb= Pb+Qb*i;
Pc= 0.4;
Qc= 0.3;
Sc= Pc+Qc*i;
% Terminal Voltage at Transformer primary
VA= 1;
VB= -0.5-0.866i;
VC= -0.5+0.866i;
% Terminal Voltage at Transformer secondary
Va= VA*(0.866025+0.5i);
Vb= VB*(0.866025+0.5i);
Vc= VC*(0.866025+0.5i);
a= -0.5+0.866i;
% Phase current, Transformer secondary side
Ia= conj(Sa/Va);
Ib= conj(Sb/Vb);
Ic= conj(Sc/Vc);
% Phase current, Transformer Primary side
IA = Ia*(0.866025-0.5i);
IB = Ib*(0.866025-0.5i);
IC = Ic*(0.866025-0.5i);
%Sequence current in system
Iseq = (1/3) * [1 a a^2; 1 a^2 a; 1 1 1]*[IA; IB; IC]; %
Iseq = [Iseq(1); Iseq(2); 0]; % As delta configuration will eliminate zero
serquence current.
I2= [real(Iseq(2)); imag(Iseq(2)); 0];
A= [1.5 -2.99 1.5; 2.598 -0.0001 -2.598; 1 1 1];
I2netbefore= Iseq(2)
B= inv(A)*I2;
Bab=B(1)
Bbc=B(2)
Bca=B(3)
A= [1 a^2 a];
V= [VA-VB 0 VA-VC; VB-VA VB-VC 0; 0 VC-VB VC-VA];
I2SVC= A*V*B
I2netafter = Iseq(2)-I2SVC
11. 11 | P a g e
%% CASE:2- With power factor correction
% Load data as provided
Pa= 0.4;
Qa= 0.3;
Sa= Pa+Qa*i;
Pb= 0.4;
Qb= 0.3;
Sb= Pb+Qb*i;
Pc= 0.4;
Qc= 0.3;
Sc= Pc+Qc*i;
% Terminal Voltage at Transformer primary
VA= 1;
VB= -0.5-0.866i;
VC= -0.5+0.866i;
% Terminal Voltage at Transformer secondary
Va= VA*(0.866025+0.5i);
Vb= VB*(0.866025+0.5i);
Vc= VC*(0.866025+0.5i);
a= -0.5+0.866i;
% Phase current, Transformer secondary side
Ia= conj(Sa/Va)
Ib= conj(Sb/Vb)
Ic= conj(Sc/Vc)
% Phase current, Transformer Primary side
IA = Ia*(0.866025-0.5i);
IB = Ib*(0.866025-0.5i);
IC = Ic*(0.866025-0.5i);
S1= VA*conj(IA);
P1= real(S1);
Q1= imag(S1);
% Phi1= atan(Q1/P1);
% PF1= cos(phi1);
P2=P1;
PF2= 0.8;
PF= 1; % As provided
Q2= P2*tan(acos(pf2))
Q3= Q1-Q2;
K= Q3/VA^2
% Q2new= Q3+Q2avg
pfnew= P2/(sqrt(P2^2+Q3^2))
%Sequence current in system
Iseq = (1/3) * [1 a a^2; 1 a^2 a; 1 1 1]*[IA; IB; IC]; %
Iseq = [Iseq(1); Iseq(2); 0] % As delta configuration will eliminate zero
serquence current.
12. 12 | P a g e
I2= [real(Iseq(2)); imag(Iseq(2)); K];
A= [1.5 -2.99 1.5; 2.598 -0.0001 -2.598; 1 1 1];
B= inv(A)*I2
Bab=B(1)
Bbc=B(2)
Bca=B(3)
A= [1 a^2 a];
V= [VA-VB 0 VA-VC; VB-VA VB-VC 0; 0 VC-VB VC-VA];
I2SVC= A*V*B
I2net = Iseq(2)-I2SVC
Conclusion:
In both the cases it is observed that the net negative sequence flowing in the
system is reduced with introduction of SVC. It is observed that the SVC based FCTCR
reduce the negative sequence current with variable switching of Thyristor. It is also
important that SVC also supplies reactive power in case of power factor
improvement.
In this project we have learnt about operation of FC-TCR based Static VAR
Compensator and how to implement SVC for negative sequence current reduction
and power factor improvement. The approach followed is quite unique and novel
method which can be widely implemented to overcome the consequences of
negative sequence current in modern power system.
Learning outcome:
1) Thesis: The prevention of super synchronous resonance problem on the
turbine system of generator with staticvar compensator
References:
By Jen-hung chen
2) Negative sequence current reduction for generator turbine protection
Wei-jen lee, Tze-yee ho, member, Jih-phong liu, Yuin-hong liu, IEEE member