The document discusses using an artificial neural network (ANN) controller to minimize harmonics injected into distribution systems by thyristor-controlled static var compensators (SVCs). SVCs are commonly used to compensate for loads but can inject harmonics. The proposed ANN controller is used to control the SVC to balance reactive power drawn from the supply and minimize harmonics injected into the system quickly. The ANN approach provides an effective and low-cost method to reduce reactive power and harmonics under unbalanced loads.

1. AURORA’S RESEARCH AND
TECHNOLOGICAL INSTITUTE
ANN Based SVC Switching at
Distribution Level for Minimal Injected
Harmonics
Presented By
A.Yateesh Kumar Yadav
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

2. Electrical distribution system suffers from various problems like reactive
power burden, unbalanced loading, voltage regulation and harmonic
distortion. Though DSTATCOMS are ideal solutions for such systems, they
are not popular because of the cost and complexity of control involved. Static
Var Compensators (SVCs) remain ideal choice for such loads in practice due
to low cost and simple control strategy. This is used to minimize the
harmonics injected into the distribution systems by the operation of TSC-TCR
type SVC. ANN is used to solve this nonlinear problem. The scheme with
Artificial Neural Network (ANN) is attractive and can be used at distribution
level where load harmonics are within limits.

3.  The Indian power distribution systems are facing a variety of problems due to nonlinear loads in the last decade. In addition to poor voltage profile, the power factor
and harmonics of the system are the major concerns of the utility.
 Thyristor controlled Static Var Compensators (SVCs) are popularly used in
modern power supply systems for compensating loads.
 A Static Var Compensator generally consists of a Thyristor Controlled Reactor
(TCR) & a Thyristor Switched Capacitor (TSC) and compensates loads through
generation or absorption of reactive power.
 The controller is used to control the SVC so that it balances the reactive power
drawn by the supply, minimize the reactive power drawn from the supply and
minimize the harmonics injected into the system in an acceptable time.

4.  In this, for compensation shunt type connections are used because generally
voltage is maintained constant and current is variable.
 Thus series, series-series & series-shunt connections are not used for
compensations due to variable voltage.
 For shunt type compensation the techniques used for reducing harmonics are
1) SVC
2) STATCOM
3) DSTATCOM
 SVC, STATCOM are used in transmission lines whereas DSTATCOM are used in
distribution.
 Thus, 99% SVC or STATCOM are used and 1% DSTATCOM is used.

5.  ANN is a one type of controller which is used to solve non-linear
problem caused due to harmonics.
 SVCs are popularly used in modern power supply systems for
compensating loads. SVCs, while correcting power factor, inject
harmonics into the lines.
 ANN controller is used to control the SVC so that it balances the
reactive power drawn by the supply and minimize the harmonics injected
into the system in an acceptable time.

6.  Advantages
1) Unlimited data transfer.
2) Higher efficiency within compensating techniques.
 Disadvantages
1) It is very costly.
2) Working process is complex.

7.  These type of techniques can be used in
1) Transmission Line
2) Sub-Stations
3) Micro-Grid
Thus, this type of control techniques are used for minimization of
harmonics but present this are not used in India due to cost point of
view.

8. Static Var Compensators (SVCs) remain ideal
choice for fast changing loads due to low cost
and simple control strategy. The proposed
ANN based approach can be effectively used
to reduce and balance the reactive power
drawn from the source under unbalanced
loadings while keeping the harmonic injection
into the power system. The computational time
required was found to be satisfactory for the
system considered.