FIRING ANGLE SVC MODEL FOR ANALYZING THE PERFORMANCE OF TRANSMISSION NETWORK USING NEWTON RAPHSON...

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International Journal of Electrical Engineering & Technology (IJEET) Volume 7, Issue 5, September–October, 2016, pp.44–61, Article ID: IJEET_07_05_005

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FIRING ANGLE SVC MODEL FOR ANALYZING THE

PERFORMANCE OF TRANSMISSION NETWORK

USING NEWTON RAPHSON LOAD FLOW

A.Hema Sekhar

Research Scholar, Department of EEE,

S.V.University College of Engineering, Tirupati, India.

Dr.A.Lakshmi Devi

Professor & HOD, Department of EEE,

S. V. University College of Engineering, Tirupati, India.

ABSTRACT

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.

Key words: Flexible AC Transmission System (FACTS), Voltage collapse Prediction Index

(VCPI), Static VAR Compensator (SVC) and Newton Raphson Method.

Cite this Article: A.Hema Sekhar and Dr.A.Lakshmi Devi, Firing Angle SVC Model for

Analyzing the Performance of Transmission Network using Newton Raphson Load Flow.

International Journal of Electrical Engineering & Technology, 7(5), 2016, pp. 44–61.

http://www.iaeme.com/IJEET/issues.asp?JType=IJEET&VType=7&IType=5

Firing Angle SVC Model for Analyzing the Performance of Transmission Network using Newton Raphson Load

Flow


1. INTRODUCTION

The operation of power system is becoming more and more challenging because of continuously

increasing load demand which is leading to an augmented stress of the transmission lines, voltage

instability, increase in loss and cost. To meet the ever increasing demand it is now essential to maximize

the utilization of the existing transmission system. In recent years, due to advancement in high power

solidstate switches, transmission controllers have been developed which provides more flexibility and

controllability. A new solution for controlling power flow known as FACTS was introduced in 1988 by

Hingorani [1]. FACTS devices have made the power system operation more flexible and secure. They have

the ability to control, in a fast and effective manner. FACTS controllers minimizes loss, enhance the

voltage profile and the load ability of power systems. FACTS devices include Thyristor Controlled Series

Compensator (TCSC), Static VAR Compensator (SVC), Static Compensator (STATCOM), Unified Power

Flow Controller (UPFC), etc.

In this paper, SVC is used for several reasons. The most widely used shunt FACTS devices within

power networks is the SVC due to its low cost and good performance in system enhancement. It is more

conventional and available. SVC can control voltage with higher level of accuracy. It is a shunt connected

static VAR generator or absorber whose output is adjusted to exchange capacitive or inductive current so

as to provide voltage support and when installed in a proper location, it can also reduce power losses [27].

For these reasons, SVC is chosen over other FACTS devices in this paper.

2. LITERATURE SURVEY

In the literature many people proposed different concepts about the placement and sizing of the SVC.

Hadi Saadat Presented Real and Reactive Power flow equations in polar form by considering two bus

power system. A Jacobean matrix is then constructed and Newton Raphson method is used to solve these

equations [1]. Hingorani N.G et.al presented about the Fast development of power electronics introduces

the use of flexible ac transmission system (FACTS) controllers in power systems. The main benefit of

FACTS devices is reduction of operation and transmission investment costs, increasing the power transfer

capabilities, system security, controlling power flow in the lines and in improving stability [2]. [3]-[4]

papers refer that , SVCs are the combination of mechanically controlled and thyristor controlled shunt

capacitors and reactors. Ref [5]-[6] papers proposed the most popular model of SVC's is the combination

of either fix capacitor and thyristor controlled reactor or thyristor switched capacitor and thyristor

controlled reactor .Ref[7]-[10] papers proposes Existing Basic model of SVC and the novel Firing angle

model for Static VAR Compensator (SVC) FACTS devices. In that paper, it explains the power electronic

development, fixed capacitor and reactor reactive power compensator has replaced with variable reactance

reactive power compensator. Kumar, G.R et.al presented about load flow analysis with incorporated

FACTS controllers in multimachine power systems from different operating conditions viewpoint. The

Newton Raphson Methods have been proposed in literatures includes for different types of Modeling of

Series FACTS controllers[11] .B.Venkateswara rao et.al explains the Implementation of Static VAR

Compensator for Improvement of Power System Stability[12] Sahoo et.al (2007) proposed the basic

modeling of the FACTS devices for improving the system performance[13].Zhang, X.P et.al explains

Jacobian Matrix of Power flow Newton Raphson algorithm and Newton Raphson strong convergence

characteristics [14].Gotham.D.J and G.T Heydt (1998) detailed about the optimal location of FACTS

devices allows controlling its power flows and thus enhances the reliability of the power systems

[15].Povh.D(2000) proposed the nice concepts of the modeling of the power systems and the impact of the

FACTS devices on the transmission network [16]. Ref [17]-[20] papers presented the lot of techniques

have been developed in predicting the closeness of the system to voltage instability in order to counteract

this effect. The prediction is based on voltage collapse prediction index [VCPI] have been used to identify

the bus which is more prone to voltage instability. Modelling of the FACTS devices with various

techniques with complete computer programming and the operating state determine the maximum power

A.Hema Sekhar and Dr.A.Lakshmi Devi


carrying capability of the network elements is proposed by Acha et.al. [21].The impact of multiple

compensators in the system was proposed by Radman.G and R.S Raje [22].The important concepts of the

power systems with different load flow was proposed by Stagg.G.W et.al(1968) [23]. Tong Zhu and Gamg

Haung proposed (1999) the accurate points of the buses which were suitable for the FACTS devices

installation [24].P.Kessal and H. Glavitsch (1986) proposed increase the transmission capability,

improvement of stability by installing FACTS devices in transmission network [25].

3. NEWTON RAPHSON METHOD OF POWER FLOW

The Newton-Raphson method is widely used for solving non-linear equations. It transforms the original

non-linear problem into a sequence of linear problems whose solutions approach the solutions of the

original problem. Load-flow studies [7] are very common in power system analysis. Load flow allows us

to know the present state of a system, given previous known parameters and values. The power that is

flowing through the transmission line, the power that is being generated by the generators, the power that

is being consumed by the loads, the losses occurring during the transfer of power from source to load, and

so on, are iteratively decided by the load flow solution, or also known as power flow solution. In any

system, the most important quantity which is known or which is to be determined is the voltage at different

points throughout the system. Knowing these, we can easily find out the currents flowing through each

point or branch.

Since within the power flow problem real power and voltage magnitude are nominal for the voltage-

controlled buses, the power flow equations [1] are developed in polar type. For the standard bus of the

facility system shown in Figure 1

Vi V1 V1

V2

Ii

Vn

Vj yi0

Figure1 A Typical bus of the power system

The current entering bus i is given by

Ii = Vi ∑=

n

j 0

yij - ∑=

n

j 1

yijVj j = i (1)

This equation can be written in terms of the bus admittance matrix as

Ii = ∑=

n

j 1

Yij Vj (2)

In the above equation, j includes bus i. expressing this equation in polar form, we have

Ii =∑=

n

j 1

|Yij| |Vj|∟θij+ δj (3)

yi1

yi2

yin


Flow


The complex power at bus i

Pi-j Qi = Vi* Ii (4)

Substituting from 2.3 for Ii in 2.4

Pi-jQi=|Vi|∟δi∑=

n

j 1

|Yij||Vj|∟θij+δj (5)

Separating real and imaginary parts

P� = ∑ |V�|�� V��Y��Cos�θ�� + δ� − δ�� = P��|V|, δ� �6�

Q� = ∑ |V�|�� V��Y��Sin�θ�� + δ� − δ�� = Q��|V|, δ� �7�

The power mismatch equations ΔP and ΔQ are expanded around a base point (θ(0),V(0)) and, hence,

the power flow Newton–Raphson algorithm is expressed by the following relationship.

∆∆

∂

∂

∂

∂∂

∂

∂

∂

=

∆

∆

V

V

VV

QQ

VV

PP

Q

P θ

θ

θ (8)

Where

P∆ is the change of real power at the bus.

Q∆ is the change of reactive power at the bus.

θ∂

∂P is the change in real power w.r.t angle at the buses

VV

P

∂

∂ is the change in real power w.r.t change in voltage magnitude at the buses

θ∂

∂Q is the change in reactive power w.r.t angle at the buses

VV

Q

∂

∂ is the change in reactive power w.r.t change in Voltage magnitude at the buses

∆ V is the change in voltage at the bus

θ∆ is the change in angle at the bus

4. SHUNT COMPENSATION

Shunt compensation is widely used in power system to enhance loadability and to improve voltage

stability. At buses where reactive power demand increases, bus voltage can be controlled by

connecting capacitor banks in parallel to a lagging load . Capacitor banks supply part of or full

reactive power of load, thus reducing magnitude of the source current necessary to supply load.

Consequently the voltage drop between the sending end and the load gets reduced, power factor will

be improved and increased active power output will be available from the source. Depending upon

load demand, capacitor banks may be permanently connected to the system or can be varied by

switching ON or OFF the parallel connected capacitors either manually or automatically (M.L.Soni,

P.V.Gupta and U.S.Bhatnagar, 1994).

Shunt compensation is of two types:

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4.1. Shunt Capacitive Compensation

This method is used to improve the

transmission line, power factor lags because of lagging load current. To

connected which draws current leading the source

4.2. Shunt Inductive Compensation

This method is used either when charging the

receiving end. Due to very low, or no load

capacitance in the transmission line causes voltage amplification (

voltage may become double the sending end voltage (gen

compensate, shunt inductors are connected across the transmission line.

The Examples of shunt compensation are Thyristor controlled reactor (TCR), Static Synchronous

Compensator (STATCOM), Thyristor

etc.

5. STATIC VAR COMPENSAT

A static var compensator ( SVC ) is the first generation shunt compensator. It has been around since 1960s.

In the beginning it was used for load compensat

loads, for flicker mitigation etc. However with the advancement of semiconductor technology, the SVC

started appearing in the transmission systems in 1970s. Today a large number of SVCs are connected

many transmission systems all over the world. An SVC is constructed using the thyristor technology and

therefore does not have gate turn off capability.

A typical SVC consists of Thyristor

(TSCs) or a fixed Capacitor in parallel. The output of the compensator is controlled in steps by sequentially

switching of TCRs and TSCs . The need for harmonic filtering as part of the compensator scheme could be

eliminated by stepwise switching of reactors r

construction model of SVC device.

Figure2


EET/index.asp 48

ompensation

This method is used to improve the power factor. Whenever an inductive load is connected to the

transmission line, power factor lags because of lagging load current. To compensate, a shunt capacitor is

connected which draws current leading the source voltage. The net result is improvement in power factor.

ompensation

either when charging the transmission line, or, when there is very low load at the

receiving end. Due to very low, or no load – very low current flows through the transmi

capacitance in the transmission line causes voltage amplification (Ferranti effect

voltage may become double the sending end voltage (generally in case of very long transmission lines). To

compensate, shunt inductors are connected across the transmission line.


Compensator (STATCOM), Thyristor Switched reactor (TSR), Thyristor Switched Capacitor (TSC) and

STATIC VAR COMPENSATOR (SVC)

is the first generation shunt compensator. It has been around since 1960s.

In the beginning it was used for load compensation such as to provide var support for large industrial


started appearing in the transmission systems in 1970s. Today a large number of SVCs are connected


therefore does not have gate turn off capability.

A typical SVC consists of Thyristor-Switched Reactors (TSRs) and Thyristor

s) or a fixed Capacitor in parallel. The output of the compensator is controlled in steps by sequentially


eliminated by stepwise switching of reactors rather than continuous control.. The figure shows the basic

construction model of SVC device.

Figure2 The basic construction model of SVC device.

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. Whenever an inductive load is connected to the

compensate, a shunt capacitor is

. The net result is improvement in power factor.

, or, when there is very low load at the

very low current flows through the transmission line. Shunt

Ferranti effect). The receiving end

erally in case of very long transmission lines). To


Switched reactor (TSR), Thyristor Switched Capacitor (TSC) and

is the first generation shunt compensator. It has been around since 1960s.

ion such as to provide var support for large industrial


started appearing in the transmission systems in 1970s. Today a large number of SVCs are connected to


Switched Reactors (TSRs) and Thyristor-Switched Capacitors

s) or a fixed Capacitor in parallel. The output of the compensator is controlled in steps by sequentially


ather than continuous control.. The figure shows the basic


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6. FIRING ANGLE MODEL S

The SVC consists of a group of shunt

means of thyristor switching. The firing angle model for SVC is shown in figure 2.

SVC's normally include a combination of mechanically controlled and thyristor controlled shunt

capacitors and reactors [3], [4]. The most popular configuration for continuously controlled SVC's is the

combination of either fix capacitor and thyristor contr

thyristor controlled reactor [5], [6]. As far as steady

modeled along similar lines. The SVC structure shown in Fig. 2 is used to derive a SVC model t

considers the TCR firing angle α

than those currently available in open literature. The variable TCR equivalent reactance, X

fundamental frequency, is given by [5] ,

!"# = ! . %

&�%'(�)*��&(�

Where α is the thyristor's firing angle.

The SVC effective reactance X

"# �+,.+-

.,/.�&�%'(�)*��&(��'+-

In general, the transfer admittance equation for the variable shunt compensator is,

)()( iVjBiI svcsvc =

Where

The SVC equivalent susceptance is given by (4) whilst its profile, as function of firing angle,

(1

−=−=

Lc

TCRcsvc XXX

BBB

XL = wL.XC =

01

and the reactive power equation is,


Flow

EET/index.asp 49

FIRING ANGLE MODEL STATIC VAR COMPENSATOR

The SVC consists of a group of shunt-connected capacitors and reactors banks with fast control action by


Figure 3 The Firing angle model of SVC



combination of either fix capacitor and thyristor controlled reactor or thyristor switched capacitor and

thyristor controlled reactor [5], [6]. As far as steady-stale analysis is concerned, both configurations can be

modeled along similar lines. The SVC structure shown in Fig. 2 is used to derive a SVC model t

as state variable. This is a new and more advanced SVC representation

than those currently available in open literature. The variable TCR equivalent reactance, X

fundamental frequency, is given by [5] ,

(9)

is the thyristor's firing angle.

The SVC effective reactance Xeq is determined by the parallel combination of X

(10)


(11)

susceptance is given by (4) whilst its profile, as function of firing angle,

])2sin)(2[ ααππ

+−−c

L

XX (12)

(13)

and the reactive power equation is,


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connected capacitors and reactors banks with fast control action by




olled reactor or thyristor switched capacitor and

stale analysis is concerned, both configurations can be

modeled along similar lines. The SVC structure shown in Fig. 2 is used to derive a SVC model that

as state variable. This is a new and more advanced SVC representation

than those currently available in open literature. The variable TCR equivalent reactance, XLeq,, at

is determined by the parallel combination of XC and XLeq,


susceptance is given by (4) whilst its profile, as function of firing angle,



]}2sin)(2[{2

svcsvcc

L

Lc

kk

XX

XX

VQ ααπ

π+−−

−=

(14)

From the equation (14) , the linearized SVC equation is given by as

∆

∆

−=

∆

∆

svc

k

svc

L

k

i

k

k

X

VQ

P

α

θ

απ

]1)2[cos(2

0

002

)(

(15)

7. VOLTAGE COLLAPSE PREDICTION INDEX (VCPI)

The technique [VCPI] is derived from the basic power flow equation. The technique is applicable for any

number of buses in a system. It needs the voltage phasor information of the participating buses in the

system and the network admittance matrix. Using the measured voltage phasors and the network

admittance matrix of the system, the voltage collapse prediction index (VCPI) is calculated at every bus.

The values of these indexes determine the proximity to voltage collapse at a bus. The detailed derivation of

the technique [VCPI] is given in Appendix 7 of the Ref [17] paper. The power flow equations are resolved

by Newton Raphson methodology that creates a partial matrix. By setting the determinant of the matrix to

zero, the index at bus k is written as follows:

k

N

kmm

m

kV

V

VCPI

∑≠

=

−=

,1

'

1

(16)

Where,

234 = 567

∑ 56898:;,8<6

23 (17)

Vk is the voltage phasor at bus k

Vm is the voltage phasor at bus m

Ykm is the admittance between bus k and m

Ykj is the admittance between bus k and j

k is the monitoring bus

m is the other bus connected to bus k

N is the bus set of the system

The value of VCPI varies between zero and one. If the index is zero, the voltage at bus k is taken into

account stable and if the index is unity, a voltage collapse is claimed to occur. VCPI is calculated solely

with info of voltage phasor of taking part buses and impedance of relating lines. The calculation is

straightforward while not matrix conversion. The technique offers quick calculation which may be applied

for on-line watching of the power system

8. SIMULATION RESULTS

The proposed system is applied is two different test cases which are IEEE 14 and IEEE 57 bus systems by

using MATLAB software.


Flow


8.1. Test case 1: IEEE 14 Bus System

The single line diagram of IEEE 14 bus system is shown in the figure 1 and the voltage profile for IEEE 14

bus system without SVC is shown in figure 2.

Figure 4 Single line diagram of IEEE 14 bus system.

Figure 5 Voltage profile of IEEE 14 bus system without SVC

8.1.1. Single SVC Placement

The placement of shunt compensating device which is SVC is determined by VCPI. The highest value of

VCPI reveals the suitable location of SVC The placement of single SVC by using VCPI is implemented on

IEEE 14 bus system. The VCPI values of the IEEE 14 bus system is shown in the table 1. From the table 1,

the single SVC is placement is decided at 14 bus The VCPI is high at 14th

bus, so shunt compensating

device such as SVC is optimally placed at 14th

bus of the system By placing SVC at 14th

bus location of

the transmission network the real and reactive power losses are reduced.. The real and reactive power

losses are reduced to 9.44 MW and 49.44 MVar. The voltage profile, total real and reactive power losses

without placing of SVC and with the placing of single SVC are shown in the figure 3,4and 5 respectively.

0 2 4 6 8 10 12 141.01

1.02

1.03

1.04

1.05

1.06

1.07

1.08

1.09

1.1

1.11

busnumbers

voltage m

agnitude in p

.u

Voltage profile without SVC device



Table 1 Voltage Collapse Prediction Index (VCPI) of IEEE 14 bus system

Bus no VCPI

1 0.1760

2 0.0679

3 0.2060

4 0.1529

5 0.1300

6 0.2591

7 0.2319

8 0.2184

9 0.2874

10 0.2967

11 0.2827

12 0.2920

13 0.2993

14 0.3408

Figure 6 Voltage profile of IEEE 14 bus with and without single SVC .

0 2 4 6 8 10 12 141.01

1.02

1.03

1.04

1.05

1.06

1.07

1.08

1.09

1.1

1.11

busnumbers

voltage m

agnitude in P

.U

voltage profile with and without SVC

without SVC

with SVC


Flow


.

Figure 7 Total Real power losses of IEEE 14 bus with and without single SVC.

Figure 8 Reactive power losses of IEEE 14 bus with and without single SVC.

8.1.2. Placement of Two SVC’s

With the inclusion of two SVC’s in the bus system i.e one SVC is locate at 14th

bus and second SVC is

locate at 13th

bus then the power flows are further improved and losses further are reduced which is shown

in the table 2. The voltage profile, total real and reactive power losses without placing of SVC and with the

placing of two SVC’s are shown in the figure 6,7 and 8 respectively.

1 20

1

2

3

4

5

6

7

8

9

10

without SVC with SVC

real power lo

sses(M

w) with a

nd w

ithout svc

TOTAL REAL POWER LOSSES WITH AND WITHOUT SVC

1 20

10

20

30

40

50

60


reactive p

ow

er lo

sses(M

Var) w

ith a

nd w

ithout svc

TOTAL REACTIVE POWER LOSSES WITH AND WITHOUT SVC



Figure 9 Voltage profile of IEEE 14 bus with and without two SVCs

Figure 10 Total Real power losses of IEEE 14 bus with and without two SVCs

Figure 11 Total Reactive power losses of IEEE 14 bus with and without two SVCs

0 2 4 6 8 10 12 141.01

1.02

1.03

1.04

1.05

1.06

1.07

1.08

1.09

1.1

1.11

busnumbers

voltage m

agnitude in P

.U


without SVC

with SVC

1 20

1

2

3

4

5

6

7

8

9

10


real power losses(M

w) with a

nd w

ithout svc


1 20

10

20

30

40

50

60


reactive p

ower losses(M

Var) w

ith a

nd w

ithout svc



Flow


Table 2 Comparative system parameters of IEEE 14 bus with and without SVC

Parameters Without SVC With SINGLE

SVC

With TWO

SVC’S

Minimum Voltage(p.u) 1.01 at bus 3 1.0044 at bus 13 0.998 at bus 13

Maximum Voltage(p.u) 1.09 at bus 8 1.049 at bus 2 1.047 at bus 2

Real power

losses(MW)

9.682 9.44 9.32

Reactive power

losses(MVar)

50.04 49.44 48.44

Location of SVC ---------- 14th bus 14

th bus.

13th bus

SVC 1firing angle(deg) ---------- 138.3 134.3

SVC2 firing angle(deg) ---------- ------ 124.3

Size of SVC1(kVar) ----------- 2.3 1.3

Size of SVC2(KVar) ---------- ------ 0.983

From the above table, it is shown that without SVC the Real and Reactive power losses are 9.682 MW

and 50.04 MVar.In case placing single SVC the losses are Reduced i.e Real and Reactive power losses are

9.44 MW and 49.44 MVar and for two SVC’s 9.32 MW & 48.44 MVar.

8.2. Test case 2 : IEEE 57 bus

The single line diagram of the IEEE 57 bus system is shown in the figure 9. The improvement of voltage

profile, the reduction of total real and reactive power losses, are shown in the figure 9..

Figure 12 Single line diagram of the IEEE 57 bus system.



8.2.1. Single SVC Placement

The placement of single SVC by using VCPI is implemented on IEEE 57 bus system. By placing single

SVC at 33rd

bus location of the transmission network, the real and reactive power losses are reduced.. The

real and reactive power losses are reduced to 27.864 MW and 119.27 MVar from 27.964 MW and 121.67

MVar. The voltage profile, total real and reactive power losses without placing of SVC and with the

placing of single SVC are shown in the figure 10,11and 12 respectively.

Figure 13 Voltage profile of IEEE 57 bus with and without single SVC

Figure 14 Total Real power losses of IEEE 57 bus with and without single SVC

0 10 20 30 40 50 600.92

0.94

0.96

0.98

1

1.02

1.04

1.06

busnumbers

voltage m

agnitude in P

.U


without SVC

with SVC

1 20

5

10

15

20

25

30


real power lo

sses(M

w) with a

nd w

ithout svc



Flow


Figure 15 Total Reactive power losses of IEEE 57 bus with and without single SVC

8.2.2. Placement of Two SVC’s

With the inclusion of two SVC’s in the bus system i.e one SVC is locate at 33rd

bus and second SVC is

locate at 51th bus then the power flows are further improved and losses further are reduced which is

shown in the table 3. The voltage profile, total real and reactive power losses without placing of SVC and

with the placing of two SVC’s are shown in figures 13,14 and 15 respectively.

Figure 16 Voltage profile of IEEE 57 bus with and without two SVCs

1 20

20

40

60

80

100

120

140


reactive p

ower lo

sses(M

Var) w

ith a

nd w

ithout svc


0 10 20 30 40 50 600.92

0.94

0.96

0.98

1

1.02

1.04

1.06

busnumbers

voltage m

agnitude in P

.U


without SVC

with SVC



Figure 17 Total Real power losses of IEEE 57 bus with and without two SVCs

Figure 18 Total Reactive power losses of IEEE 57 bus with and without two SVCs

1 20

5

10

15

20

25

30


real pow

er lo

sses(M

w) w

ith a

nd w

ithout svc


1 20

20

40

60

80

100

120

140


reactive p

ow

er lo

sses(M

Var) w

ith a

nd w

ithout svc



Flow


Table 3 Comparative system parameters of IEEE 57 bus with and without single & two SVCs

Parameters Without SVC With SINGLE SVC

With TWO SVC’S

Minimum

Voltage(p.u)

0.936 at bus 31 0.9638 at bus 26 0.9618 at bus 26

Maximum

Voltage(p.u)

1.06 at bus1

1.0412 at bus 49 1.0392 at bus 49

Real power

losses(MW)

27.964 26.864 26.424

Reactive power

losses(MVar)

121.67 119.27 115.27

Location of SVC ---------- 33rd

bus

33rd

bus,

51 bus

SVC 1firing

angle(deg)

---------- 122.3 126.3

SVC2 firing

angle(deg)

---------- ------- 124.3

Size of

SVC1(kVar)

----------- 3.82 1.74

Size of

SVC2(KVar)

---------- ------- 2.35

From the above table, it is shown that without SVC the Real and Reactive power losses are 27.964 MW

and 121.67 MVar.In case placing single SVC the losses are Reduced i.e Real and Reactive power losses

are 26.864 MW and 119.27 MVar and for two SVC’s 26.424 MW & 115.27 MVar.

9. CONCLUSION

In this paper, the optimal location and optimal sizing of SVC device is find out to minimize voltage

deviation and the active power losses in the power system network using Newton Raphson Technique. The

Firing Angle Model of Static VAR Compensator (SVC) using Newton Raphson method has been

implemented on IEEE 14 and 57 bus test systems to investigate the performance of power transmission

line in absence as well as in presence of single and double SVC devices. It is found that during presence of

single SVC there is reduction of real and reactive power losses and also voltage profile improvement as

compared to absence of SVC and with double SVCs also there is reduction in losses and there is more

improvement in voltage profiles .The results obtained by application of the N-R technique during firing-

angle model based control are found to be very much similar with the reactance model. It is noted that as

compared to Reactance method, the implementation of the firing-angle based control of SVC using NR

technique is much easier. It is also noted that the firing-angle calculation of SVC using firing-angle model

based control is much easier as compared to impedance model based control.and this proposed method is

better than earlier published works like reactance models and power injection models.



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