Question

A factory has a sub-circuit found to have serious 5th harmonic in the current, together with other less severe harmonic orders (from 2nd to 15th order). The power factor is found to be 0.75 lagging.

(a) If a combination of active and passive harmonic filters are to be used, suggest a suitable configuration for the above factory. Illustrate your answer with simplified single-line schematic diagram, and support your choice with reasons.

Answer 1

A suitable configuration could include a combination of active and passive harmonic filters, with the active filter connected in parallel to the source and the passive filter in series with the load.

Step-by-step explanation:

In order to improve the power factor of a circuit with severe 5th harmonic and other less severe harmonic orders, a suitable configuration could include a combination of active and passive harmonic filters.

An active harmonic filter consists of power electronic components and is capable of generating currents that cancel out the harmonic components in the system. Passive harmonic filters, on the other hand, use passive components such as capacitors and inductors to absorb or block the harmonics.

A possible configuration could involve connecting an active harmonic filter in parallel to the source and a passive harmonic filter in series with the load. This way, the active filter can compensate for the harmonic content generated by the load, while the passive filter can suppress the harmonic content in the current flowing to the load.