Circuit ImplementedAt low power factor, transmission lines carry both active power and reactive power and it increases line current and line losses. On the other hand supplier charges for high reactive power consumption through kVA demand. Therefore power factor correction is beneficial to the supplier in terms of line loss and also to the customer in terms bill payment.
Electrical circuit diagram of the studied system
Power factor correction capacitor bank can be used for power factor improvement in industries, which are normally having highly inductive loads. When the power factor correction capacitor bank is connected to the system with inductive loads total current drawn from the supply is reduced. This confirms that the supplier current is reduced and thus the maximum kVA demand also reduced.
However, the capacitor bank introduces more harmonics to the system. This can be observed from the load and supplied waveforms shown in Figures 3 and 4.
When a rectifier harmonic load is added to the system, it injects more harmonic current to the grid. In this case according to the characteristics of the power factor correction capacitors, they show low impedance to harmonic current. Therefore the capacitor current is increased. However, in this experimental set up a small harmonic load was used and also the supply voltage consist harmonics due to neighborhood harmonic loads . Therefore significant increment in the harmonic current could not be seen when harmonic load was added. As a result it can be concluded that the harmonic current increased in the power factor correction capacitors when harmonic loads are added to the grid in neighborhood areas.
@Power lab,faculty of Engineering
University of Peradeniya, SL.
