17-06-2013, 12:38 PM
Power Quality issue & Harmonics
Power Quality issue.ppt (Size: 872 KB / Downloads: 32)
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.
Good power quality would be a reliable supply of sinusoidal, 60Hz waveforms resulting in few operational anomalies.
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
Voltage Fluctuations
Lights flickering? It could be the result of voltage fluctuations in your facility's electrical system.
High- and low-voltage conditions can result in equipment damage, data loss and erroneous readings on monitoring systems.
Overloaded power circuits are typically the cause behind under-voltage conditions.
Heavily loaded motors such as air conditioners can result in intermittent low voltages.
Less common but more damaging are over-voltage conditions, which can be seen in facilities that have rapidly varying loads.
Harmonics affect Power Quality
Equipment to fail prematurely.
Decrease the efficiency of the electrical. distribution and utilization network.
Causes grounding potential rise.
light flickering.
Faulty operation of Computerized data processing equipments and computer. networks and computer equipment.
Active filter
Use op amps with resistor and capacitors in their feed loops.
Active filters can have high input impedance ,low out put impedance .
Easier to design than passive filters.
Using Op amp can achieve very good accuracy.
Types of Shunt filters
Switched Tuned Arm Power filters (STAF)
Switched Damped power filters (S.C-Type)
Switched Asymmetrical Tuned Arm Filter (SATAF).
Switched Combined Tuned Arm filter and Static Capacitor Compensator.
Switched Static Capacitor Compensator
Switched Blocking Filter
Summery
Power Quality becoming a concern .
Awareness is growing among industries.
Utility monitors voltage , costumer dictate current .
THD, voltage sags, swells. Transient voltage.
Many nonlinear loads exist, increasing.