CONGESTION MANAGEMENT USING SVC UNDER ...CONGESTION MANAGEMENT USING SVC UNDER DEREGULATED POWER SYSTEM PL. Somasundaram 1 , V.Jayakumar 2, K.Sundararaju 3 Department of E lectrical

CONGESTION MANAGEMENT USING SVC UNDER

DEREGULATED POWER SYSTEM

PL. Somasundaram1 , V.Jayakumar2, K.Sundararaju3

Department of Electrical and Electronics Engineering

M. Kumarasamy College of Engineering, Karur-639 113, Tamilnadu, India. 1Corresponding author mail id: [email protected],

[email protected],

Abstract -

Congestion management is one of the technical challenges in a deregulated power

system. Two types of methodologies used in congestion management are cost-free and

non-cost free methods. In this project the congestion has relived by using cost-free methods

considering FACTS device. The FACTS device such as Static VAR Compensator has

proposed to improve the voltage profile. The WSCC-9 bus system was taken as test system

and it was built and analyzed using MATLAB-Power System Analysis Toolbox software.

The SVC was located at the each buses in WSCC 9 bus system and the Load flow has run

for each SVC locations to identify the optimal location of SVC. Based on this result bus

Number 5 was identified as the best location for SVC. Congestion has created manually by

adding wheeling transaction and contingency condition in separate cases. The performance

analysis has been compared for these cases with and without SVC. The result shows that

the proposed approach has the capability to improve the voltage profile of the power

system network.

Key Words: Congestion, Wheeling Transaction, Contingency, SVC, WSCC-9 Bus System,

Power System Analysis Toolbox

1. INTRODUCTION

Deregulated Environment is the Competitive Market along with the Customers. There

are many choices available for the Customers to get Electrical Energy. In Deregulated

power market the generation, Transmission and distribution are Unbundled so it is called

Horizontally unbundled system. The Generators are in the Generating companies Which

generate and supply Electrical energy to the Transmission Company. The Transmission

company transmit power to the Distribution company through the transmission components

like transmission lines and compensating devices. The distribution company controls the

operation of distribution system and supply energy to the customers. The Independent

System Operator (ISO) Collects the Bids of the buyer and seller and matches the buyer and

seller according to their bids. The condition of overload occur in the power system is

called congestion which affect the operation of the Deregulated power system. The

Congestion has caused by contingency condition and wheeling transactions.

The FACTs Devices were used to remove Congestion. The FACTS is the power

International Journal of Pure and Applied MathematicsVolume 118 No. 20 2018, 2307-2317ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu

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electronics based device which control the Power Flow in fast manner. The FACTS device

controls the series and shunt impedance, Phase angle (δ), Voltage, Current and damping of

oscillations in case of Violations in frequency from the rated frequency. There are different

types of FACTS devices Series, Shunt and combination of Series and Shunt devices. In this

paper the Shunt Compensating device Static VAR Compensator (SVC) is used to improve

the Voltage Profile in case of Congestion created by Wheeling Transaction and

Contingency condition. The Optimal location of SVC in the WSCC-9 Bus system to

improve the Voltage Profile has identified based on the Real Power Losses. The simulations

are done using PSAT (Power System Analysis Toolbox) software. PSAT is the MATLAB

based toolbox employed for controlling and analyzing the power system.

2. WHEELING TRANSACTION

The use of some parties transmission system for the benefit of other parties is called as

wheeling transaction. The parties denotes both utility and non utility organizations.

Wheeling Transaction

There are two types of wheeling transactions involved in wheeling transaction. They are,

Bilateral Transaction

Multilateral Transaction

The Wheeling transaction established between two parties in deregulated power system

environment to sell and buy Electrical Energy is called as Bilateral Transaction.

Multiple parties involves in Wheeling Transaction for selling and buying of electrical

energy is called as multilateral transaction. The multilateral transactions based on bilateral

transactions among market participants.

3. CONTINGENCY ANALYSIS

The Unpredictable events in the Power system operations are termed as Contingency.

Contingency in Power System leads to instability of entire Power System and affects the

Reliability, Security and Continuity. The contingency analysis has done by opening of

following devices to create congestion,

Generator Outage

Transformer Outage

Transmission Line Outage

4. LOAD FLOW METHODS

The study of various solution methods to power system network is called as power flow

study. The solution gives the voltages at different buses, power flowing indifferent lines and

line losses. The details derived from a power flow study is magnitude and phase angle of

International Journal of Pure and Applied Mathematics Special Issue

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voltages, real and reactive power flowing in each line and the line losses. The following

methods are useful to find the solution for load flow problem,

Gauss-Seidel method

Newton Raphson method

Fast Decoupled method

Among the above methods the N-R method gives the most accurate solution and the

number of iterations used for this method is less. So N-R method has mostly preferred for

Load Flow Solutions.

The flow chart for the N-R method has given below.

5. Static VAR Compensator

Determine the

largest of |ΔVp|2

If Δ

VP<ε

0

Evaluate bus

and load

power

E

n

d

Determine

Jacobian matrix

Calculate Δepk

& Δfpk

epk+1=ep

k+Δe

pk

fpk+1=fp

k+Δfp

k

Advance

iteration

count

K=K+1

Is

Qp<Qp

min

Check

PV Bus

Is

QP>Qp

max Advance Bus

count p=p+1

Check

p≥n

Set

QpK=Q

Pmin

Set

QpK=QP

max

Evaluate

Δ

Qpk=Qps-

Qpk

Evaluate

|ΔVP2|=|Vps|

2-|Vp|2

Set bus count

p=2

Calculate PP and QP

PP= p(eqGpq+fqBpq)+fp(fqGpq-eqBpq)},

QP= p(eqGpq+fqBpq)+ep(fqGpq-eqBpq)} Evaluate

ΔPpk=Pspec-Pp

k

S

t

a

r

t

Read load flow data and

form Y bus matrix

Set convergence= ε0

Assume initial bus voltage Vp=1+0j

for p=2, 3,..n V1=a+0j

Set

K=0


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A static VAR compensator is a parallel combination of controlled reactor and fixed shunt

capacitor shown in the figure below. The thyristor switch assembly in the SVC controls the

reactor. The firing angle of the thyristor controls the voltage across the inductor and thus the

current flowing through the inductor. In this way, the reactive power draw by the inductor

can be controlled.

Fig. Static VAR Compensator

The SVC is capable of step less adjustment of reactive power over an unlimited range

without any time delay. It improves the system stability, system power factor and it improves

the voltage magnitude of the system.

6. WSCC-9 BUS SYSTEM

This WSCC 3 Machines, 9 Bus Test Case (known as P.M Anderson 9 Bus).

Western System Coordinating Council (WSCC) to an equivalent system with nine buses

and three generators. WSCC 9 bus system has three generators, three transformers, six

transmission lines and three load buses as shown in Fig.


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7. SIMULATION RESULTS AND DISCUSSION

CASE 1: IDENTIFICATION OF BEST LOCATION OF SVC

In Case 1 the best location of SVC has identified by connecting SVC at different buses

and the load flow has run for each SVC location. By considering the real power losses the

bus no.5 has identified as the best location of SVC . The real power losses at different

locations of SVC are listed in the below table.

Table Optimal Location of SVC

SVC at Bus

No

Real Power Loss in

MW

5 4.497

8 4.5871

6 4.6182

2 4.641

3 4.641

4 4.6424

7 4.6473

9 4.6803

CASE 2: BASE CASE

Table Comparison of Base Case voltage in KV

Bus No Without SVC With SVC

1 17.16 17.16

2 18.45 18.45

3 14.15 14.15

4 235.93 238.47

5 228.99 235.75

6 232.91 234.91

7 235.93 237.61

8 233.65 234.99

9 237.44 238.21

From the Base case Power flow result with and without SVC the voltage magnitude

comparison has done. From the above result it was identified that the voltage profile has

improved by using SVC at bus 5.


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CASE 3: BILATRAL TRANSACTION

Table Bilateral Transaction

From Bus To Bus Amount of

Transaction in MW

5 6 20

The Bilateral Transaction has done bus number 5 and 6 which has given in the

above Table.

Table Bilateral Transaction Voltage Profile comparison

Bus No Voltage Profile in KV

Without SVC With SVC

1 17.16 17.16

2 18.45 18.45

3 14.14 14.15

4 235.95 238.28

5 229.55 235.75

6 232.17 234.02

7 236.01 237.56

8 233.63 234.86

9 237.31 238.02

In case of Bilateral Transaction between the buses 5& 6 the voltage profile has reduced as

shown in above Table.

CASE 4: MULTILATERAL TRANSACTION

Table Multilateral Transaction

From

Bus To Bus

Amount of

Transaction in

MW

Total

Transaction

in MW

5 8 12.5

25 6 12.5

The Multilateral Transaction has done between the buses 5,6&8. 25MW was removed from

Bus 5 and it was injected into Bus 8&6 as 12.5MW each.

The Multilateral transaction creates congestion in the system and voltage get reduced

as shown in below Table 8.6 and it also increased by using SVC.


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Table 8.6 Comparison of Multilateral Transaction voltage profile

Bus No

Voltage Profile in KV

Without

SVC With SVC

1 17.16 17.16

2 18.45 18.45

3 14.15 14.15

4 236.21 238.38

5 229.99 235.75

6 232.69 234.41

7 236.01 237.45

8 233.45 234.6

9 237.33 237.99

Fig Comparison of Real Power Losses in Wheeling Transaction

The real power loss in case of wheeling transaction with SVC has reduced as shown in

above fig.

CASE 5: OUTAGING OF TRANSFORMER BETWEEN BUS 3&9

Table Voltage Profile for transformer between Bus 3&9 outage



1 17.16 17.16

2 18.45 18.45

3 0 0

4 237.11 239.2

5 230.64 235.75

6 234.61 236.75

7 236.42 237.98

8 234.36 236.15

9 238.86 240.81


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Table Real Power Loss in case of Transformer Outage

Transformer

Outage Without

SVC

With

SVC From

Bus To Bus

3 9 3.6285 3.4972

2 7 4.4347 4.3894

CASE 6: OUTAGE OF TRANSMISSION LINE BETWEEN BUS 5&7

Table Contingency Ranking for Transmission Line Outage

Transmission Line

Outage

With SVC

Real

Power

Loss in

MW

Contingency

Ranking From

Bus To Bus

5 7 12.7037 1

7 8 11.3954 2

6 9 8.9503 3

4 5 6.691 4

4 6 6 5

8 9 5.2441 6

The above Table shows the Contingency Ranking of the Transmission lines based on the

real power losses in case of transmission line outage. The transmission line between the

Buses 5&7 has higher losses than others.

CASE: 7 OUTAGE OF GENERATOR at BUS 3

Table Voltage Profile in case of Generator at Bus 3 Outage



1 17.16 17.16

2 18.45 18.45

3 14.33 14.45

4 237.11 239.2

5 230.64 235.75

6 234.61 236.75

7 236.42 237.98

8 234.36 236.15

9 238.86 240.81


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Table Real Power Loss in case of Generator Outage

Generator

Outage Without SVC With SVC

2 4.4347 4.1725

3 3.6285 3.4972

From the above table it has identified that the voltage profile and the real power losses has

reduced in case of generator outage and this has improved using SVC at bus 5.

8. CONCLUSION

This project has proposed the cost free congestion management method required for

smooth operation of deregulated power system. The cost free method using SVC gives the

remedy for congestion by enhancing the voltage profile. The WSCC-9 bus system was

taken as test system and it was built using MATLAB-PSAT software. The power flow has

run for base case without SVC. The SVC was connected to each load buses in the WSCC-9

bus system and the load flow has run for each cases to find the optimal location of SVC.

The congestion has created by Wheeling transaction and Contingency condition in separate

cases. The Load Flow has run for these cases with and without SVC. From the comparative

power flow analysis of with and without SVC, it can be concluded that the SVC has given

the best result by improving the voltage profile in case of wheeling transaction and

contingency condition.

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Documents

CONGESTION MANAGEMENT USING SVC UNDER ...CONGESTION MANAGEMENT USING SVC UNDER DEREGULATED POWER SYSTEM PL. Somasundaram 1 , V.Jayakumar 2, K.Sundararaju 3 Department of E lectrical