In one of our last blogs, we discussed about the problems occurring in the industry due to harmonics generated by non-linear loads. Click here to read. In this blog, we shall see some basics of harmonic filters, their types and their working.
Let’s start with a story. There lives a king of a kingdom of old India. He is a great king. He loves his subjects and takes care of them. Now you are appointed as chief of his personal guards and you are to arrange sec
urity of the king. What will you do? You will arrange security such that only good people shall have access to the king. So you shall arrange the security in a way that either the bad people would get killed or would get diverted to exit gate. Right?
Now consider your or your client’s critical machine is the king. Good people are the 50Hz pure sine wave voltage and bad people are all the harmonics. So your aim would be to either not allow these harmonics to come to your machine or to divert them to earth. And in this case the guard will be harmonic filter. So harmonic filters either restricts the harmonics to enter your systems under protection or it diverts the harmonics so that they never enter the systems under protections.
Based on whether harmonic filters will restrict the harmonics or divert the harmonics, there are two types of filters –
- Series Harmonic Filters
- Shunt Harmonic Filters
Series Harmonic Filter
Series harmonic filter restricts the harmonics to pass through them. It is designed in such a way that the current with harmonic frequencies are not passed through them (high impedance) but the pure sine wave of 50Hz or 60Hz (depending on the system) passes easily through them (low impedance). This filter is fitted in line with the power supply and the machine or system under protection.
Shunt Harmonic Filter
Shunt harmonic filter bypasses the harmonics to the ground. It is designed in such a way that the current with harmonic frequencies are easily passed through them (low impedance) but the pure sine wave of 50Hz or 60Hz (depending on the system) do not pass through them (high impedance). These filters are connected in shunt with the line from power supply and machine or system under protection.
All what we discussed are about passive filters. There are active filters too. We shall discuss about them in future blogs.
We, at SYCON, offer services of harmonic analysis, passive harmonic filter design, manufacturing and installation. For more information please drop us a message or give a phone call.
Our sole purpose is to remove chaos from the electrical power and keep making this world greener and greener.
Good Luck !!