Slide 1

ELECTRIC POWER QUALITY- AN INTRODUCTION

GUIDENCE OF: UPENDAR RAO

G.MOUNIKA 00 08PR1A0221

What is a Quality Power?A perfect power supply would be one that is always available, always within voltage and frequency tolerances and has a pure noise-free sinusoidal wave shape.

PQ - Is it a Serious Issue?A fault on the network may cause a dip that will affect some customers and the higher the level of the fault, the greater the number affected, or a problem on one customers site may cause a transient that affects all other customers on the same subsystem.

Power quality defects:Blackouts

Harmonic distortion

Transients

Under or over voltage

Dips (or sags) and surges

Typical distortion caused by rectifier loads on a local Generator, (a) Half Load, (b) Full Load

Extreme distortion caused by Thyristor loads on a local Generator.

Harmonic distortion

Representation of a distorted waveform.

TunedHarmonicFilters

Detuned Filters

Thyristor Switched Capacitor Bank Active Filter

LT Capacitors

HT Capacitor Banks

Transients

VOLTAGE EVENTS

Under voltage

Over voltage

Voltage sags

Voltage Swells

Unbalanced Voltages

Voltage Fluctuations

Voltage sags, Swells & Unbalance

VOLTAGE EVENTSDISTURBANCE EFFECTOvervoltageOverstress insulation Under voltageExcessive motor current UnbalanceMotor heating Neutral-groundDigital device malfunction InterruptionComplete shut-downSagVariable speed drive & computer trip-outSwellOverstress insulationFluctuationsLight flicker

Conclusion This centers objective must be towards work with industry to improve the quality and reliability of the electricity supply to industrial, commercial and domestic users.

Thank You