A short and easy tutorial of introduction to Power Quality Phenomena,Problems and Solutions available in the current industry for the same.“Any event related to the electrical network which ultimately results in financial loss” is called a Power Quality problem. Ultimately if you see we wouldn’t bother spending on reducing the power quality problems otherwise, would we? Yeah, the next sections will be very useful in your understanding of Power Quality problems and solutions. We can classify the Power Quality problems as follows. This is with respect to the severity in terms of effects due to the specific phenomena.
1. Reactive Power / Power Factor
2. Harmonics
3. Unbalance
4. Voltage Dips/Sag
5. Interruptions
5.1 Short Interruptions
5.2 Long Interruptions
6. Transients, Surges (Switching, Lightning etc.,)
7. Flicker
8. Voltage Drops/Peaks (Long Duration)
9. Earthing and EMC
Now in the further studies we can see, for each of the topics in detail. For each of the above phenomena we are going to address the following,
a. What is the phenomena?
b. How and/or why it is created in the Power System?
c. What are the problems created due to that?
d. What are the solutions available?
e. Which solution to choose?
f. What are the benefits on addressing this Problem?
g. Which Company product to Choose?
REACTIVE POWER / POWER FACTOR
What is Reactive Power (kvar)?
By definition to understand what reactive power (kvar) is, one has to be clear with Real or Active Power (kW), Apparent Power (kVA) as these three are interconnected. Though reactive power is one of most important aspect of electricity, it is one of the most difficult part to comprehend also. To explain this we are going to use a very interesting analogies. Presenting these analogies for the easy understanding of the reader though it might not be 100% correct. Coffee Mug Analogy In Coffee Mug Analogy, the real, reactive and apparent powers are explained using only the magnitude of the respective values. In the above analogy it clearly states the following,
kW is Working Power (also called Actual Power or Active Power or Real Power). It is the power that actually powers the equipment and
performs useful work.
kvar is Reactive Power. It is the power that magnetic equipment (transformer, motor, relay etc.) needs to produce the magnetizing flux.
kVA is Apparent Power. It is the “vectorial summation” of kvar and kW From the above anybody can clearly tell why we have to reduce the kvar, because the value of the kW (Coffee) will reduce for the Mug if the kvar is more, right? Let’s look at a simple analogy in order to better understand these terms.
Reactive Power (kvar)
Real Power (kW)
Apparent Power (kVA)
Let’s say it’s Friday evening, and you are with your friends at your favorite pub after a really hot day. You order up a big mug of your favorite Coffee for you and for your friends. The thirst-quenching portion of your Coffee is represented by kW. Unfortunately, life isn’t perfect. Along with your Coffee, comes a little bit of foam. (And let’s face it, that foam just doesn’t quench your thirst.) And this foam is
represented by kvar. The total contents of your mug, kVA, is this summation of kW (the Coffee) and kvar (the foam). So, now that we understand some basic terms, we are ready to learn about power factor: Power Factor is the ratio of Active Power (kW) to the Apparent Power (kVA)
𝑃𝑜𝑤𝑒𝑟 𝐹𝑎𝑐𝑡𝑜𝑟 =
𝑘𝑊
𝑘𝑉𝐴
Looking at the Coffee Mug we can say kVA is the sum of kW and kvar, so,
𝑃𝑜𝑤𝑒𝑟 𝐹𝑎𝑐𝑡𝑜𝑟 =
𝑘𝑊
𝑘𝑊 + 𝑘𝑣𝑎𝑟
𝑃𝑜𝑤𝑒𝑟 𝐹𝑎𝑐𝑡𝑜𝑟 =
𝐶𝑜𝑓𝑓𝑒𝑒
𝐶𝑜𝑓𝑓𝑒𝑒 + 𝐹𝑜𝑎𝑚
So in simple terms anybody can understand that when we have lesser kvar
that means there is more kW (Useful Power) for the system and obviously more
Coffee than Foam, which is good . Now we also know that the kW, kvar and the
kVA are vector quantities, so to understand this in the vector form it is shown to
