Seminar on
APPLICAION OF ANN CONTROLLER IN A FACTS DEVICE : D-STATCOM

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Under the guidance of Presented By
ANIL K.DAHIYA PROFFESOR G.SIVA VIKRAM YADAV
Dept of Electrical Engineering MTECH P.E.D - 208249
National Institute of Technology Kurukshetra Dept of Electrical Engineering,
Haryana-136119, India N.I.T. KUKUKS

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Power Quality
The ideal quality of power supply is characterized by electric power energy with perfect sinusoidal waveform at constant frequency of specified constant voltage with least amount of interruptions.



What are power quality problems ?
It include all possible situations in which the waveforms of the supply voltage or load current deviate from the sinusoidal waveform at rated frequency with amplitude corresponding to the rated rms value for all three phases of a three-phase system

Power quality disturbance covers sudden, short duration deviation impulsive and oscillatory transients, voltage dips (or sags), short interruptions, as well as steady- state deviations, such as harmonics and flicker

Voltage Power Quality Problems
Voltage Sag
Voltage Swell
Voltage Interruption
Under/ Over Voltage
Voltage Flicker
Harmonic Distortion
Voltage Notching
Transient Disturbance
Outage and frequency variation



Voltage Sag
A voltage sag is a reduction in the RMS voltage in the range of 0.1 to 0.9 p.u. (retained) for duration greater than hall a mains cycle and less than 1 minute. Often referred to as a Ëœsagâ„¢. Caused by faults, increased load demand and transitional events such as large motor starting.

Voltage Swell
A voltage swell is an increase in the RMS voltage in the range of 1.1 to 1.8 p.u. for a duration greater than half a main cycle and less than 1 minute. Caused by system faults, load switching and capacitor switching.

Voltage Interruption
A voltage interruption is the complete loss of electric voltage. Interruptions can be short duration (lasting less than 2 minutes) or long duration. A disconnection of electricity causes an interruption”usually by the opening of a circuit breaker, line recloser, or fuse

Over Voltage and Under Voltage
Long-duration voltage variations that are outside the normal limits (that is, too high or too low) are most often caused by unusual conditions on the power system. For example, out-of-service lines or transformers sometimes cause under voltage conditions. These types of root-mean-square (RMS) voltage variations are normally short term, lasting less than one or two days.
In addition, voltage can be reduced intentionally in response to a shortage of electric supply.


Voltage Flicker
A waveform may exhibit voltage flicker if its waveform amplitude is modulated at frequencies less than 25 Hz, which the human eye can detect as a variation in the lamp intensity of a standard bulb.
Voltage flicker is caused by an arcing condition on the power system.
Flicker problems can be corrected with the installation of filters, static VAR systems, or distribution static compensators
Harmonics Distortion
Harmonics are periodic sinusoidal distortions of the supply voltage or load current caused by non-linear loads.
Harmonics are measured in integer multiples of the fundamental supply frequency.
In commercial facilities, computers, lighting, and electronic office equipment generate harmonic distortion. In industrial facilities, adjustable-speed drives and other power electronic loads can generate significant amounts of harmonics.
Solutions to problems caused by harmonic distortion include installing active or passive filters at the load or bus, or taking advantage of transformer connections that enable cancellation of zero-sequence components.
Distorted Voltage Waveforms
Voltage Notching
Voltage notching is caused by the commutation of power electronic rectifiers. It is an effect that can raise PQ issues in any facility where solid-state rectifiers (for example, variable-speed drives) are used

When the drive DC page link current is commutated from one rectifier thyristor to the next, an instant exists during which a line-to-line short circuit occurs at the input terminals to the rectifier.

With this disturbance, any given phase voltage waveform will typically contain four notches per cycle as caused by a six-pulse electronic rectifier
Voltage Notching Waveform
Transient Disturbance
Transient disturbances are undesirable momentary deviation of the supply voltage or load current and caused by the injection of energy by switching or by lightning.

Transients are classified in two categories Impulsive and oscillatory


Outage
Outage is defined as an interruption that has duration lasting in excess of one minute.

Frequency Deviation
It is a variation in frequency from the nominal supply frequency above/below a predetermined level, normally + 0.1%.
Effects of PQ Quantities

Voltage dips
machine/process downtime, scrap cost, clean up costs, product quality and repair costs all contribute to make these types of problems costly to the end-user

Transients
tripping, component failure, hardware reboot required, software ˜glitches˜, poor product quality

Harmonics
transformer and neutral conductor heating leading to reduced equipment life span; audio hum, video Ëœflutterâ„¢, software glitches, power supply failure

Flicker
visual irritation




Current Based Power Quality Problems
Reactive Power Compensation

Voltage Regulation

Current Harmonics Compensation

Load Unbalancing (for 3-phase systems)

Neutral Current Compensation (for 3-phase 4-wire systems)
Sources of Power Quality Problems
Power electronic devices
IT and office equipments
Arching devices
Load switching
Large motor starting
Embedded generation
Sensitive equipment
Storm and environmental related damage
Solution of Power Quality Problems
Static Var Compensator
Passive Filter
Active Filter
Multi-pulse Configuration
D-STATCOM
DVR
UPQC

Solution of Power Quality Problems

Mitigation of Voltage Dips and Short Interruption

Motor-generator set

Static series compensator

Dynamic voltage restorer (DVR)

Static transfer switch
Other Possible Solutions
Proper earthing practices

Online UPS/Hybrid UPS

Energy storage system

Ferro- resonant transformer

Network equipment and design
Custom Power Devices
(Static Compensators)
Distribution Static Compensator (DSTATCOM)

DSTATCOM 1-Phase 2-Wire
DSTATCOM 3-Phase 3-Wire
Simulated Performance of 3-Phase 3-Wire DSTATCOM
DSTATCOM 3-Phase 4-Wire
Mid-Point Capacitor Topology
Four Pole Topology of DSTATCOM
Three Single-Phase VSC Topology of DSTATCOM
Simulated Performance of 3-Phase 4-Wire DSTATCOM
Control Scheme
ARTIFICIAL NETWORKS
INTRODUCTION
Artificial neural networks offer an alternative way to tackle complex and ill-defined problems. They can learn from examples, are fault tolerant in the sense that they are able to handle noisy and incomplete data, are able to deal with non-linear problems, and once trained can perform predictions and generalizations at high speed. They have been used in diverse applications in control, robotics, pattern recognition, forecasting, medicine, power systems, manufacturing, optimisation, signal processing
Neural Networks
The ANNs are good for some tasks, while lacking in some others. Specifically.
they are good for tasks involving incomplete-data sets, fuzzy or incomplete information, and for highly complex and ill-defined problems.
Biological and artificial neurons

In the brain, there is a own of coded information (using electrochemical media, the so-called neurotransmitters) from the synapses towards the axon.

Articificial Neural Networks
two points have to be addressed
An artificial neural network is a collection of connected McCulloch-Pitts neurons.
(1) How many hidden layers to use?
(2) How many neurons to choose in each hidden layer?


Training neural networks
The result of a neural network is its weight set. Determining an appropriate weight set is called training or learning.
Learning rules or methods:
Hebb's rule (multi-layered neural networks )
Random search methods (iterative)
1. genetic algorithm
2. back propogation algorithm
3. simulated annealing.



Developing a neural network controller
I have chosen Matlab for developing a neural network controller. This can be done using ËœNN TOOL BOXâ„¢.

References
H. Akagi, Y. Kanazawa, A. Nabae, "Instantaneous Reactive Power Compensators Comprising Switching Devices Without Energy Storage Components", IEEE Trans. on Industry Applications, Vol.IA-20, No.3, May/June 1984, pp.625-630.

Bhim Singh, Kamal-Al-Haddad and Ambrish Chandra, A review of active filters for power quality Improvement, IEEE Trans. on Industrial Electronics, vol. 46, no. 5, Oct. 1999. pp 960-970.

Ambrish Chandra, Bhim Singh, B.N. Singh and Kamal-Al-Haddad and An improved control algorithm of shunt active filter for voltage regulation, harmonic elimination, power-factor correction, and balancing of nonlinear loads IEEE Trans on Power Electronics Vol. 15, no 3, pp 495 “ 507, May 2000.

B. Singh, V. Verma, A. Chandra and K. Al-Haddad. Hybrid filters for power quality improvement IEE Proc.-Gener. Transm. Distrib., Vol. 152, No. 3, pp. 365-378,May 2005

El-Habrouk, M., Darwish, M.K., and Mehta, P.: ˜Active power filters: A review™, IEE Proc., Electr. Power Appl. vol. 147, pp. 493“413, 2000.
References
Arindam Ghosh, and Gerard Ledwich Power Quality Enhancement using custom power devices, Kluwerâ„¢s Power Electronics and Power System series, U.S.A, 2002.

A. Ghosh, and G. Ledwich, Compensation of distribution system voltage using DVR, IEEE Trans. Power Delivery, vol. 17, pp. 1030 “ 1036, Oct. 2002.

A. Ghosh, K. Jindal, A. Joshi, Design of a capacitor-supported dynamic voltage restorer (DVR) for unbalanced and distorted loads,IEEE Trans. Power Electron., vol.19, pp. 405-413, Jan. 2004.

I. Etxeberria-Otadui, U. Viscarret, S. Bacha, M. Caballero, and R. Reyero, Evaluation of different strategies for series voltage sag compensation, in Proc. IEEE PESC™02, vol. 4, 2002, pp. 1797 “ 1802.

Chi-Jen Huang, Shyh-Jier Huang, and Fu-Sheng Pai, Design of dynamic voltage restorer with disturbance-filtering enhancement, IEEE Trans. Power Electron., vol. 18, pp. 1202 “ 1210, Sept. 2003.

pls can u provide full report