Most Electricity supply companies in Australia are now charging a KVA demand tariff in addition to KWH tariff, which could result in higher electricity charges for the customer. In addition, supply companies also prescribe by regulation minimum power factor levels for customer installations.
KVA demand is directly related to the Power Factor of the electrical - electronic equipment installed. Some Electrical equipment has poor Power Factor. For example, SCR – Thyristor controlled rectifiers. When the output voltage is reduced from the rated output, the Power Factor changes to very Poor, possibly down to 0.25.
KVA demand increases as the Power Factor decreases, say from very good, PF 0.95 down to a very poor PF 0.25
So if possible buy electrical equipment that has a very Good Power Factor, which is normally between 0.90 to 0.95 and which is maintained between these two levels, especially when the output voltage of the rectifier is reduced. This will keep the KVA tariff costs lower, ensure the installation complies with regulations and possibly avoid having to purchase costly Power Factor correction equipment.