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46th ISTE Annual National Convention & National Conference 2017
International Journal of Advance Research and Innovation (ISSN 2347 – 3258)
Analytical Improvement of Voltage Profile of a 14
Bus Test System using SVC.
Nirbhai Singh
Gulzar College of Engineering, Khanna
Punjab, India
[email protected]
Vishal Kumar Mittal
Gulzar College of Engineering, Khanna
Punjab, India
[email protected]
limits without the necessity of adding new transmission lines.
FACTS
controllers provide flexibility in power flow control over
transmission systems and increase the line loading in some
cases up to the maximum limits. These controllers can provide
new control facilities both in steady state for the purpose of
power flow control. With their ability to change the apparent
impedance of transmission line and capability for shunt power
compensation, FACTS controllers may be used for active
power control, as well as reactive power control or voltage
control. FACTS controllers also find important role in
restricted electricity marked by increasing system load and the
power exchange capability between two areas.
Abstract— In modern power system the transmission network
become very complex and stressed due to growing demand and
constraint on building new transmission line.
Due to complex and stressed system, the power system losing
stability and voltage profile. The FACTS devices are used to reduced
the stress from the transmission line and boost the voltage level of the
system. SVC is used to boost the voltage level of the system. In this
paper SVC control the power flow and flow of reactive power.
In this paper capability of SVC has been checked on IEEE standard
14 bus system. The proposed model analysis the IEEE14 test bus
system with and without FACTS device
keywords — FACTS, load flow, psat
I.
INTRODUCTION
A
Power Generation and Transmission is a complicated process,
many devices are used to maximize the output of power
system. The active and reactive powers are main part of
electrical power, but the reactive power is major part because
most industrial loads like motor loads are reactive loads. To
improve the AC power system, required to manage the
reactive power in well manner. There are two major
techniques, which are used to improve the reactive power. One
is load compensation and voltage support compensation. In
load compensation consist of improve the power factor and
balancing of real and reactive power drawn from the supply,
for better voltage profile. In large fluctuation the voltage
support is required. In recent years static Var compensation
like STATCOM and SVC developed. The SVC and
STATCOM having special property to absorbed and generate
the reactive power with fast response. SVC and STATCOM
are allow to improve the transfer of apparent power throw AC
transmission line. Flexible AC Transmission system
technology is being prompted as a means to extend the
capacity of existing power transmission networks to their
Selection of study domain:
In this dissertation, IEEE 14 bus test system is considered
which is investigated under different loading conditions.
B
Objectives:
 To improve the voltage profile of IEEE 14 bus test
system.

C

To improve the reactive and active power of IEEE 14
bus test system
Methodology:
Simulation of IEEE 14 bus test system using PSAT
and load flow studies carried out from simulated
IEEE 14 bus system in order to investigate the
weakest bus of the system.

Increment of load at weakest bus of the system and
there by investigating the voltage profile of the
system.

Installation of SVC at weakest bus and there by
obtaining the voltage profile of the system.
1
Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA)
46th ISTE Annual National Convention & National Conference 2017
International Journal of Advance Research and Innovation (ISSN 2347 – 3258)

buses be ng such that n = np + ng + 1. Bus-1 is assumed to be
the slack bus. The approach to Newton-Raphson load flow is
similar to that of solving a system of nonlinear equations using
the Newton-Raphson method: at each iteration we have to
form a Jacobian matrix and his equation is of the form.
Comparison of the voltage profile of system with and
without SVC .
II. LOAD FLOW STUDIES.
  2
 
  Vn
 2
V2
J


  V1 n p

 V1 n p
The steady state power and reactive powers supplied by a bus
in a power network are expressed in terms of nonlinear
algebraic equations. We therefore would require iterative
methods for solving these equations.
A
Real and reactive power injected in a bus
The formulation of the real and reactive power entering a bus,
we need to define the following quantities. Let the voltage at
the ith bus be denoted by
Vi  Vi  i  Vi cos i  j sin  i 
(1.7)
where the Jacobian matrix is divided into sub matrices as
(1.1)
Define the self admittance at bus-i as
Yii  Yii ii  Yii cosii  j sin ii   Gii  jBii
J
J   11
 J 21
(1.2)
Similarly the mutual admittance between the buses i and j can
be written as
Yij  Yij  ij  Yij cos  ij  j sin  ij 

 P
  2 
  Pn 
   Q2 
   
  Q1 n p 

 

(1.8)
J11: (n  1)  (n  1), J12: (n  1)  np, J21: np  (n  1)
 Gij  jBij and J22: np  np
The sub matrices are
(1.3)
Let the power system contains a total number of n buses. The
current injected at bus-i is given as
 P2
 
 2
J11   
 Pn
  2

I i  Yi1V1  Yi 2V2    YinVn
n
  YikVk
k 1
(1.4)
Assume the current entering a bus to be positive and that
leaving the bus to be negative. As a consequence the power
and reactive power entering a bus will also be assumed to be
positive. The complex power at bus-i is then given by
 Vi


n
  YikViVk
k 1
J12
 cosik  j sinik  cos  k  j sin k 
J 21
 cos  i  j sin i  cosik  j sinik  cos  k  j sin k 
Pi  YikViVk
cos ik

 V2



 V2


P2
 V2

Pn
 V2

V1 n p


V1 n p
P2


 V1 n p 


Pn 

 V1 n p 

(1.10)
(4.5)
Therefore substituting in (1.5) we get the real and reactive
power as
n
P2 
 n 


 
Pn 

 n 


(1.9)

 n
Pi  jQi  Vi I i  Vi  YikVk
k 1
n
cos  i  j sin  i  YikVk
k 1
J 12 
J 22 
 Q2
 
2



 Q1 n p
 
2

(1.11)
J 22
 k  i 
k 1
(1.6)



Q2
 n

Q1 n p
 n
Q2

 V2  V
2




Q1 n p
 V2
 V2










V1 n p


V1 n p
Q2 

 V1 n p 


Q1 n p 

 V1 n p 

(4.12)
Formation of the Jacobian Matrix
We shall now discuss the formation of the sub matrices of the
Jacobian matrix. To do that we shall use the real and reactive
power equations of (4.6). Let us rewrite them with the help of
(4.2) as
n
Qi   YikViVk sin  ik   k   i 
k 1
B
Load flow by Newton-Raphson method
Let us assume that an n-bus power system contains a total
number of np P-Q buses while the number of P-V (generator)
2
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46th ISTE Annual National Convention & National Conference 2017
International Journal of Advance Research and Innovation (ISSN 2347 – 3258)
Pi  Vi
2
 M 22  M 2 n 


J 21   

 
M

 np 2  M npn 
n
Gii   YikViVk cos ik   k   i 
k 1
k i
(1.13)
n
Qi   Vi Bii   YikViVk sin  ik   k   i 
2
(1.21)
From (4.10) it is evident that the elements of J21 are the partial
derivative of Q with respect to . From (4.13) we can write
k 1
k i
(1.14)
A. Formation of J11
Let us define J11 as
J11
Q
 L22

 

 Ln 2
L2 n 
 

Lnn 




M
ik
M ii 
n
J 12
(1.16)
n
Qi   Vi Bii   YikViVk sin  ik   k   i 
Q i
 i

n
  Yik Vi Vk cos  ik   k   i
k 1
 Pi  Vi
2
G ii
k i
 N 22
  
 Nn 2

 N2n
p


 N nn
p





Pi
 YikViVk cos ik  k  i
N ik  Vk
 Vk
(1.17)
   M ik
i
k
(1.25)
A. Formation of J11
Let us define J11 as
For i = k we have
 L2 n 
  
 Lnn 
Pi
N ii  Vi
 Vi
(1.18)
It can be seen from (1.9) that Mik’s are the partial derivatives
of Pi with respect to k. The derivative Pi (1.13) with respect to
k for i  k is given by

n
Vi  2 Vi Gii   YikVk
k
1

k i


 2 Vi
2

cos ik  k  i 


n
G ii   YikViVk cos  ik  k  i
k 1

  2 Vi
2
G ii  M ii
k i
Pi
  YikViVk sin  ik   k   i , i  k
 k
(1.26)
Formation of J22
(1.19)
Similarly the derivative Pi with respect to k for i = k is given
by
J 22
n
Pi
  YikViVk sin ik   k   i 
 i k 1
 O22  O2 n 
p


 

 
O

 n p 2  On p n p 
(1.27)
For i  k
k i
Comparing the above equation with (1.39) we can write
Lii 
k
(1.24)
k 1
k i
Lii 
i  k
(1.23)
k i
Lik 

Formation of J12
Let us define J12 as
k 1
 L22
J11   
 Ln 2

  Y V V cos      ,
ik i k
ik
k
i
(1.22)
Pi  Vi Gii   YikViVk cos ik   k   i 
2

i
Similarly for i = k we h
(1.15)
We shall now discuss the formation of the sub
matrices of the Jacobian matrix. To do that we shall use the
real and reactive power equations of (1.6). Let us rewrite them
with the help of (1.2) as
2

Oik  Vi
Pi
2
 Qi  Vi Bii
 i
Qi
 Vk

(1.28)
(1.20)

  Vi Yik ViVk sin  ik   k  i  Lik ,
Finally for i = k we have
B. Formation of J21
Let us define J21 as
3
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ik
46th ISTE Annual National Convention & National Conference 2017
International Journal of Advance Research and Innovation (ISSN 2347 – 3258)
Qi
O ii  Vi
 Vk

 2 Vi

n
Vi   2 Vi Bii   YikVk
k 1

k i

2

sin ik  k  i 


n
B ii   YikViVk sin  ik  k  i
k 1

  2 Vi
IV. RESULT AND DISCUSSION
2
B ii
k i
(1.29)
We therefore see that once the sub matrices J11 and J21 are
computed, the formation of the sub matrices J12 and J22 is
fairly straightforward. For large system this will result in
considerable saving in the computation time.
A Load flow of ieee14 bus system using Newton Rapson
method with the help of PSAT software without FACTS.
Make the IEEE 14 bus system using PSAT software define its
 L ii
all parameters which are necessary for load flow of IEEE14
bus system e.g. generators, loads, transformer ratings, buses.
Convert the 3phase transmission line into pi model of
transmission line. Do the load flow of IEEE14 bus system
using Newton Rapson method and find all the parameters of
IEEE14 bus system.
III. POWER FLOW MODEL OF SVC
SVC is a shunt connected device. SVC device is belonging to
FACTS family, with the use of power electronics SVC control
the power flow, and improve the transient stability. SVC also
enhances the voltage profile by controlling the reactive power.
SVC injects and absorbed the reactive power from the line.
When voltage of the system goes low SVC act as a reactive
power generator. When voltage goes high SVC absorbed the
reactive power from the line. The reactive power variation
performed by capacitor bank with electronics switching, each
capacitor bank is switching by three SCR. TSC reactor also on
off by SCR. Phase control by TCR.
Non-linear power equations and the linearised equations
required by Newton’s method.
Fig 4.1 (IEEE 14 bus system using PSAT)
The parameters which are obtained after load flow of IEEE 14
using Newton Rapson methods with the help of PSAT are
given below
Show in table no 1 the bus No.14 is weakest bus in IEEE 14
bus system. Because the voltage magnitude at 14 number bus
is less than all other buses the voltage magnitude at 14 bus is
0.98631 p.u. which is less as comparison to other buses. Take
the 14 no bus for analysis.
Voltage differential equation can be written as given below
X TCR is the reactance of the TCR.
Where.
Now write the equation in the term of firing angle
The reactance of the SVC can be obtained by parallel
combination of Xc and X TCR
Where.
The reactive power equation can be written as given below
Fig 4.2(voltage profile without facts)
4
Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA)
46th ISTE Annual National Convention & National Conference 2017
International Journal of Advance Research and Innovation (ISSN 2347 – 3258)
V. INCREMENT OF LOAD AT 14 BUS.
The bus number 14 is a weakest bus. So bus number 14 is
used for analysis. Increased the load at 14 no bus with 5%
increment up to 40%. When the load is increased the voltage
level decrease at bus no.14.It goes to below the limit which is
define at PSAT software during simulation of 14 bus system.
The both type of load is increased at bus no.14. the table of
load increment at 14 bus is given below.
Show in below given diagram as well as the load increased the
at bus no 14 the voltage profile decrease. At without load the
voltage at bus no.14 is 0.98631 p.u . but as well as load
increased the voltage at bus no 14 decreased at 40% load the
voltage at bus no. 14 goes to 0.9666 p.u. which is very less
than limit which is define at PSAT software.
Fig- 6.1 IEEE 14 bus system with SVC using PSAT
The application of SVC was initially for load compensation of
fast changing loads such as steel mills and arc furnaces. Here
the objective is to provide dynamic power factor improvement
and also balance the currents on the source side whenever
required. The application for transmission line compensators
commenced in the late seventies. Here the objectives are:
Show in fig the SVC is connected at bus no.14 because the bus
no. 14 is the weakest bus in system, so the SVC is connected
at bus no. 14. The rating of SVC is power 100 MV, voltage
13.8 KV and frequency 50 Hz. The gain of SVC T2 10 p.u
and reference voltage 1.00p.u alpha max 1.00 p.u and alpha
minimum -1.00. Km 1.00 p.u, Tm .01p.u. the inductance and
capacitance .20Xl p.u and .10 Xc p.u respectively gain is
50p.u. the SVC is device which suck and inject the reactive
power to transmission line due to that SVC is used to maintain
the reactive power in the transmission line. Show in figure.
The SVC is connected at bus no.14.due to SVC the voltage at
bus no.14 increase, without SVC the voltage at bus no.14 is
0.98361p.u. But the voltage with SVC 1.0368SSSSp.u.when
load is increased at bus no.14. The voltage at bus no.14
decrease, but when SVC
is connected at bus no.14 the voltage level increased up
to.1.0368
Fig 5.3( load increment at 14 number bus)
After the connecting the STATCOM at bus no.14 the value of
voltage increase up to 1.04 (p.u) from 0.988. After increasing
the load 0% to 40%. The value of voltage decrease without
STATCOM but when STATCOM is connected the voltage
profile remain constant at 1.04 pu. Show in table no. the value
of voltage at bus no.14 is 1.04 p.u. Qgen become 0.09341.
Qload is 0.05
VI. LOAD FLOW USING SVC
The Static Var Compensator (SVC), first generation FACTS
Controller. It is a changeable impedance device where the
current through a reactor is controlled using back to back
connected thyristor. The function of thyristor valve technology
to SVC is an offshoot of the developments in HVDC
technology. The major dissimilarity is that thyristor valves
used in SVC are rated for minor voltages as the SVC is
connected to an EHV line through a step down transformer or
connected to the tertiary winding of a power transformer.
5
Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA)
46th ISTE Annual National Convention & National Conference 2017
International Journal of Advance Research and Innovation (ISSN 2347 – 3258)
devices,” Electric Power Systems Research, vol. 74, no. 3, pp.
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Fig-6.2 voltage profile of 14 bus system with SVC.
VII. VOLTAGE MAGNITUDE OF IEEE14 BUS SYSTEM AT
BUS NO 14 USING SVC.
With the study of SVC and STATCOM, improve the reactive
power and voltage profile of IEEE 14 bus system. The
STATCOM and SVC connect at weakest bus of IEEE 14 bus
system. SVC and STATCOM improve the voltage level at
weakest bus. The improved voltage level are plots in graphs.
Fig 7.2 (comparison of voltage profile using VAR)
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