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ACCUVAR is three phase measuring controllers, and hence need three CT inputs from the mains and also all the three phase and neutral connections. So, in addition to accurate control of VAR, this model also provides comprehensive electrical measurement. The parameters measured and displayed (depending on model selected ) are all voltages, currents, power factor, all powers and all energies, average PF maintained since last reset and THD figures for voltages and currents.

ACCUVAR has an autosense feature, which senses the sizes of the capacitor banks connected on each stage automatically. No need to programme C/K or bank sizes manually.

Since there is no fixed sequence of switching capacitors, if very small capacitor banks are connected, this controller senses down to 1% of the main load and takes corrective action.

The control parameter is VAR, and not PF. Target PF value is just used to calculate the capacitive VAR required to be added/removed to achieve the desired PF. e.g. If the target PF is unity, means that the target VAR in the system is zero.

If system KVAR is 200 lagging, then the controller needs to add 200 KVAR of capacitor banks to reach zero VAR.

The calculation of the reactive power in the system is done by taking instantaneous samples of all voltage and current waveforms, in all four quadrants. These values are then subjected to DSP techniques to add a frequency independent 90° phase shift to current samples. The product of these voltage and current samples then generate signed VAR value. VAR controller then takes into calculation the prevailing system KVAR, the prevailing bank KVAR and the bank sizes of each stage, and then switches ON/OFF the combination which is closest to the needed VAR.