This document describes a study on reactive power compensation using STATCOM conducted by students under the guidance of Dr. Supriyo Das. It provides background on reactive power and the need for reactive power compensation. It then describes Static Synchronous Compensators (STATCOM) and includes the simulation diagram and output of a voltage source converter used in STATCOM. The conclusion discusses designing a VSC using PWM to inject compensated reactive power into the main power line and future work on improving the design.

1. National Institute of Technology
Meghalaya
Project Title:-
Study of Reactive Power Compensation Using STATCOM
Under the guidance of
Dr. Supriyo Das
(Asst.Prof. EEE Dept.)
By:-
Amit Kumar Meena
Manish Kumar Singh
Avinash Kumar

2. CONTENTS
 Introduction
 Reactive power
 Power Triangle
 Need for reactive power
 Need for reactive power compensation
 Static Synchronous Compensators (STATCOM)
 Simulation Diagram of Voltage Source Converter (VSC)
 Simulation Output
 Conclusion & Future Work
 References

3. INTRODUCTION
 Reactive power (VAR) compensation is defined as the
management of reactive power to improve the performance
of ac systems. There are two aspects:-
a) Load Compensation – The main objectives are to :-
i) increase the power factor of the system
ii) to balance the real power drawn from the system
iii) compensate voltage regulation
iv) to eliminate current harmonics.
b) Voltage Support – The main purpose is to decrease the
voltage fluctuation at a given terminal of transmission line.
Therefore the VAR compensation improves the stability of ac
system by increasing the maximum active power that can be
transmitted.

4. WHAT IS REACTIVE POWER ?
Power is referred as the product of voltage and current
i.e. Total power = V x I
The portion of power that establishes and sustains the
electric and magnetic fields of alternating-current equipment
is called reactive power.
Reactive power must be supplied to most types of magnetic
equipment, such as motors and transformers.
In an ac transmission, when the voltage and current go up
and down at the same time, only real power is transmitted
and when there is a time shift between voltage and current
both active and reactive power are transmitted.

5. POWER TRIANGLE
 Power factor = cosø
= real power / apparent power
= kW/ kVA
 Whenever there is a phase shift
between V and I we have:-
a) real power (kW)
b) reactive (imaginary ) power (kVAR)
c) The combination is a complex or
apparent power (kVA)=√(kW)² + (kVAR)²

6. WHY DO WE NEED REACTIVE
POWER?
 In resistive loads the current produces the heat energy
which produces the desired output but incase of
inductive loads the current creates the magnetic field
which further produces the desired work. Therefore
reactive power is the non working power caused by the
magnetic current to operate and sustain magnetism in
the device .
 Reactive power (vars) is required to maintain the voltage
to deliver active power (watts)through transmission
lines.

7. Need for Reactive Power
Compensation
 To increase system stability.
 Better utilization of the machines connected to the system.
 Reducing losses associated with the system.
 To avoid oscillation of reactive power between load and
source.
 Also to regulate the power factor of the system and maintain
the voltage stability we need to compensate reactive power .

8. Methods of Reactive Power
Compensation
 Shunt compensation
 Series compensation
 Synchronous condensers
 Static VAR compensators
 Static Synchronous Compensators

9. Static Synchronous Compensator
 The devices use synchronous voltage sources for
generating or absorbing reactive power. A
synchronous voltage source (SVS) is constructed
using a voltage source converter (VSC). Such a
shunt compensating device is called static
compensator or STATCOM .
 A STATCOM usually contains an SVS that is driven
from a dc storage capacitor and the SVS is
connected to the ac system bus through an
interface transformer. The transformer steps the ac
system voltage down such that the voltage rating of
the SVS switches are within specified limit.

10. Structure of STATCOM
 Basically, the
STATCOM
system is
comprised of
 Power converters
 Set of coupling
reactors or a
step-up
transformer
 Controller

11. Advantages of STATCOM
 The components used in the STATCOM are much
smaller than those in the SVC.
 The characteristics of STATCOM are superior.
 The output voltage of STATCOM is nearly equal to the
input DC voltage.
 Better transient response.
 Reduction of harmonic to minimum level.
 Reduction of size of high value air-cored reactor.
 Reduction of equipment volume and foot-print.

12. Simulation model of VSC used in
STATCOM

13. Simulation output

14. Conclusion & Future Work
 From all the previous discussion we can conclude reactive power
compensation is a must for improving the performance of the ac
system. By reactive power compensation we can control the
power factor and reduce the consumption of electricity.
 So far we have designed a VSC using thyristor. From a DC
source we generated three-phase voltage each having a phase
difference of 120 degree.
 Using MATLAB programming we have to create non-stop
alternating pulsations.
 Using pulse width modulation technique (PWM) we will get a pure
sinusoidal wave.
 Finally using a step-up transformer of suitable turn ratio we will
inject this sine wave into the main power line at a particular phase
angle which will give the resultant phase difference between
voltage and current to be zero i.e Φ = 0. So, sinΦ becomes 0 and
hence the reactive power is compensated.

15. References
 Zhiping Yang, Chen Shen, Mariesa L. Crow, Lingli
Zhang, An Improved STATCOM Model for Power Flow
Analysis, University Of Missouri, 2000.
 Alper Cetin, Design and Implementation of VSC based
STATCOM For Reactive power Compensation And
Harmonic Filtering, Middle East Technical University,
2007.
 Ashok Kumar Bajia, Development of power flow model
of a STATCOM, Delhi College of Engineering, 2009.
 Timothy J. E. Miller-“Reactive Power Control in Electrical
Systems”.
 Dr. P S Bimbhra- “Power Electronics” Khanna
Publishers, Thapar Institute of Engineering and
Technology, 2012.

16. THANK YOU!!