Power Quality
Power Quality: In the present scenario of power utilization and consumption, the importance of power quality is vital for a continuous and effective power supply.
The features of power quality play a major role in effective power utilization along with the control & improvement measures for various factors affecting it.
Power quality is defined as the ability of a system to
1. Deliver electric power service of sufficiently high quality so that the end-use equipment will operate within their design specifications and
2. It should be of sufficient reliability so that the operator of end-use equipment will be continuous.
In other words, it may be defined as the concept of powering, grounding, and protecting electric equipment in a manner that is suitable to the operation of that equipment.
Why is it a concern?
Power Quality has been a problem since the conception of electricity, but only over the last 2 decades has it gotten considerable attention with the introduction of large numbers of computers & microprocessors in businesses and homes; and the network revolution and ever-increasing equipment capability and speed.
There are various factors that really make us think about it.
1. Power quality problems can cause equipment malfunctions, excessive wear or premature, failure of equipment, increased costs, increased maintenance, repair time, and expense & outside consultant expense.
2. Electronic equipment is more sensitive to minor fluctuations. We rely on the equipment more and have higher expectations. New electronic devices are more sensitive than the equipment being replaced as well.
Power Quality Affecting Factor?
Many electronic devices are susceptible to power quality problems and a source of power quality problems. Some of the important concerns are
1. Waveform Distortions like Harmonics
2. Transients
3. Voltage Fluctuations such as Voltage Sags & Swells
4. Interruptions e.g. Outages & Blinks
Control & improvement of the System
The System: In order to overcome the various affecting factors, we need to implement some control and improvement measures.
They are discussed as follows:
1. Harmonics Several techniques are adopted to minimize harmonic effects like increasing pulse number, passive filters, and active filters. By use of these techniques, we get a higher pulse, trap the harmonics, and convert the non-linear ac line current into a sinusoidal wave respectively. Power quality analysis is really a matter of concern as it is quite evident how important supply of power is especially in organizations where critical loads need a continuous supply of clean power and that too without any disruption. Technological advancements are developing in this sector in order to manage advanced and sophisticated power systems with utmost proficiency.
2. Transients We can use power enhancers like Surge Suppressors, Lightning Protection/Arrestors, Power Conditioning, Line Reactors/Chokes, etc. Power Synthesizers such as Standby Power Systems, UPS & Motor Generator Sets can be utilized. The simplest, least expensive way to condition power is by clamping voltage when it exceeds a certain level and sending it away from the equipment it protects. Transient voltage surge suppressors (TVSS) can be installed at the terminals of sensitive electronic loads. Power line filters limit noise and transients to a safe level by slowing down the rate of change of these problems and keeping electronic systems safer than surge protectors can.
3. Voltage Fluctuations such as Voltage Sags & Swells Use of Power Enhancers like Reduced Voltage Starters on large offending motors, Voltage Regulators, Constant Voltage Transformers (CVTs), Power Conditioners; as well as Power Synthesizers like UPS, Motor-Generator Sets can minimize voltage fluctuations. Voltage Regulators can be utilized to maintain voltage output within a desired limit or tolerance regardless of how much input voltage varies. They can also be utilized for protection against swells or noise and limited protection from fast voltage changes depending upon the response time of the regulator. Voltage regulators respond best to slow changes in voltage. Constant Voltage Transformers (CVTs), also known as Ferro resonant transformers are used for sags, swells, and longer-term over and under-voltages, especially attractive for constant, low-power loads like electronic controllers (PLCs) where they provide ride-through capability. Variable loads, especially those with high inrush currents, (Drives) present more of a problem for CVTs.
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