Active Harmonic Filters
Most electrical transmission and distribution systems have been designed to operate at the fundamental frequency only and the presence of non-linear loads often stress distribution equipment and can disrupt normal power supply operation.
Effects of Harmonics
- Cause transformers derating and/or overheating
- Reduces overall electrical system power factor e.g. PF0.6 (Energy wastage)
- Generators unable to switch on or Capacitor Bank burnt
- Cause Overheating to cables resulting in possible short circuit
- Interference to communication equipment – resulting in data loss
Why Improve My Harmonics?
- The harmonic components of order 3 (150 Hz) in three-phase systems become homopolar, for instance: They converge on the neutral conductor and overload it. In the absence of the neutral, circulating currents may occur inside the three-phase appliances, connected in triangular form, generating dangerous overloads in this situation as well.
- In single-phase systems, personal computers are classic examples of heavily-distorted loads with a high content of 3rd order harmonics which, as described above, will have an effect on the neutral. The conductor must, therefore, be sized appropriately, otherwise overheating will occur, thus reducing its life and quality.
- They can cause failure of PLC, DCS, computer, and other sensitive low voltage power supplies.