Management felt that their electricity costs were too high and they wanted to investigate some options that would reduce their costs and result in a return on investment in under 3 years. As is commonly the case, the peak kVA Demand occurs during a combination of full production and office air-conditioning during the warmer months (Dec, Jan & Feb). Even if this peak kVA demand is only needed for 15 minutes, it becomes the peak kVA charge for the month (according to this particular billing contract used by their supply authority). Therefore, the company was still charged the maximum amount even in a very low load month. The challenge here was to find a way of saving money by lowering the peak kVA.

The merits of power factor correction and solar power were investigated. A solar power solution was not selected as it usually provides benefit for an average of 4 hours a day over the 365 days of a year. This is due to cloud cover, bad weather and night-time which is particularly relevant when the operation is a double shift or 24 hour concern. Whereas power factor correction by using the Sinexcel SVG provides a 24-hour reduction in kVA consumption irrespective of the time of day or night and the weather conditions.

Analysis revealed that the site had a ‘real’ (kW) demand for electrical energy of 500kW and a power factor of 0.8. Power factor is expressed as kW/KVA, so the ‘apparent’ power required to produce this ‘real’ power was 500/0.8 = 625KVA. Improving the power factor will reduce this KVA and therefore reduce the supply transformer requirements or increase the available ‘real’ power from the transformer.

The Sinexcel Static Var Generator (SVG) provides for the greatest return by maintaining 0.99 lagging (or better) which allows the business to fully utilise the capacity of the supply transformer at all times. The required compensation was calculated to be 303.8kVAr. Fuseco provided three wall-mount SVG modules for installation (1 x 200kVAr, 1 x 100kVAr & 1 x 50kVAr), providing a total compensation capacity of 350kVAr. The wall mounting modules also saved valuable floor space in the company’s switch room.

By using the Sinexcel SVG Power Factor Correction Equipment, the power factor was improved to 0.99, the apparent power required to produce 500kW of real power was reduced to 505KVA, a saving of 120KVA. At 415V 3-phase, this is a reduction in switchboard current to 166A per phase. The installation was being charged on a KVA demand basis, so a tangible saving was achieved. In this case, the KVA demand charge was $8.90/KVA/month, so the following was achieved:

• A reduction in electricity charges of $1,068 / month.
• A return on investment (ROI) well under 2 years.