Thursday, 2 November 2017

How to deal with low power factor (PF) in DG sets? - Part 2

Robust Power Factor correction systems have been designed by expert power electronics developers as per the given limitations and system boundaries (in Part 1). The newly designed systems deploy the principles of the conventional Automatic Power Factor Corrector (APFC) but they differ significantly on aspects like the control logics and subsequently the controller hardware that are cutting-edge and sophisticated. In common language, this corrective mechanism is known as reactive power consumption whereby a mirror image of the tracked power factor is formed to correct it in real time.

To put this into effect you would need the below things:

1.      Thyristors with solid state relays - As the name itself suggests and unlike the conventional magnetic induction relays, these are made up of solid state electronics (semiconductors) that are helpful in eliminating transient currents and reducing the time lag between the consecutive switchovers of capacitors.

2.      Multiple current sensors-A current transformer should be available for every electrical phase of the layout. It will virtually balance the load and correct the power factor on every phase line.

3.      Microprocessor-based controllers - The additional phase-wise data parameters and the calculation of power for correction determination have rendered micro controller based controllers slow and sluggish. That is why hardcoded PLCs or faster microprocessors work better than them.

Advantages of correcting the Power Factor with the above advanced methods:

1.      More alternator efficiency- The copper losses that are associated with an alternator are directly proportional to the square of the current that it delivers. Thus, the correction of power factorwill lead to lesser current per unit power and reduce the associated copper loss.

2.      Reduced overheating and voltage fluctuations - There’ll be reduction in the currents in the total system. Due to this, overheating and voltage fluctuations in the windings and the transmission network due to the shuttling of loads is greatly reduced. This further saves T&D losses.

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