Harmonic Mitigating Transformer
The Harmonic Mitigating transformer is a three phase transformer with 0° or -30° displacement between the primary and the secondary with multi winding connections.
The Harmonic Mitigating transformer (0° or -30°) is used to reduce current harmonics on the primary side of a transformer and reduce the voltage distortion on the load. The Harmonic Mitigating transformer reduces the 3 rd harmonics and 9th , 15th , 21st on the primary side. Used together on the same power line the zig-zag 0° and the zig-zag -30° will reduce the 5th and 7th harmonic on the primary side.
In cases where stable operations are essential, these avoid high cost interruption.
When the elimination of the harmonics improves the power-factor desired.
- Health establishment: for use on equipment biomedical of first importance.
- Office buildings: for intensive use of computers, printers and others.
- Air transport: in the airports for the air supervising authority, lighting and communications.
- Zig-Zag secondary design
- K13 factor – 200% capacity neutral (double neutral)
- Epoxy impregnation
- Adjustement taps 2-3% FCAN et 2-3% FCBN
- 0o or 30o phase shifts
- 115oC et 80oC tempature rise.
- Single or Multiple electrostatic shield.
- Temperature sensor.
- Higher k factors higher than 13 available.
- Double output ( [0°, – 30°] or [-15°, + 15°] ) on same transformer.
- Different enlosures.
- Aluminum winding.
With the arrival of nonlinear loads such as computers, fax machines and variable speed transmissions our current industry faces a dilemma with the deformation of the sinusoidal wave caused by harmonics. When the presence of harmonics is critical, it is possible to attenuate these harmonics with Bemag’s harmonic mitigating units.
Used alone, a mitigating transformer reduces the third harmonics (3rd, 9th, 15th). Used on pair, these transformers with a phase shift of 0o and 30o can eliminate all the other harmonics.
Example of harmoniques correction
Here is a readings which was taken on a Zig-Zag transformer with a computer as main load.
We can observe on the 3rd harmonic (180Hz) on the secondary with 63.6A of amplitude.
This harmonic is found on the neutral of the secondary with the 2 others phases, 171A with 182Hz.
3.15 A on the primary is what remains.