20-09-2012, 04:54 PM
Power Quality Improvement and Measurement Of its Parameters
Power Quality Improvement.ppt (Size: 3.37 MB / Downloads: 83)
Definition
The term power quality means different things to different people .
Power quality is the interaction of electronic equipment within the electrical environment. This consists of generators, Transformers, breakers, wiring and grounding.
A good quality power supply would be one that is always available, always within voltage and frequency tolerances and has a pure noise-free sinusoidal wave shape.
Why is power quality so important?
Power quality is an increasingly important issue for all electrical consumer .
Problems with powering and grounding can cause data and processing errors that affect production and service quality.
Each time production is interrupted electrical consumer, your loses the margin on the product that is not manufactured and sold
Harmonics
Harmonic current are generated to small extent and at low distortion level by .
1- Generation equipment .
2- transmission equipment.
3- Distribution equipment .
4- Industrial load .
5- Domestic load.
Power filters
Filter is a device that removes something from whatever passes through it.
To eliminate line-current harmonics.
To reduce electrical interference.
Any combination of Passive (R, L and C) and/or active (transistors or operational amplifiers) elements designed to select or rejects a band of frequencies.
Mainly shunt type and usually connected in parallel with power system or electric load
Provide low impendence (ZF) path to ground for all harmonic currents at one or more tuned harmonic frequencies.
Excellent performance despite variation of the system frequency.
Self-adaptation to changes in the network impedance.
Reduced size, allowing implementation using container techniques.
In addition to reducing installation time, this makes it possible to test the complete equipment as a system at the factory before shipment.