Eskom’s power supply disruptions of 2008 have had some unexpected and positive consequences for JT International’s tobacco manufacturing facility in Wadeville, Gauteng.
As a result of last year’s power cuts, JT International (JTI) invested in a 660 kVA standby generator for its plant in Wadeville.
This project became the trigger for a rationalisation project of the company’s power distribution system, which has resulted in significant savings in energy costs and improved monitoring of power consumption.
Legacy systems
The Wadeville factory was part of the Gallaher Group prior to JTI’s purchase of the international tobacco operations of the US multinational R.J. Reynolds in 2007. The power distribution system was originally fed by a single 600 kVA transformer. In 2005 Gallaher installed an additional 2 MVA transformer. At the time of the JTI buyout, the distribution system was ageing, with imbalanced supplies and operating at a poor power factor and there was no energy monitoring of individual plant areas.
In the words of project engineer Boris Mirkovic, “The reticulation was scary and there were voltages differences between the two transformers leading to plant trips.”
Power factor correction
A multifaceted study was performed of the plant power consumption characteristics and power factor (PF) using data from Ekhureleni’s online metering facilities and external consulting company Harmonious Technical CC. These studies showed that the operating PF was around 0,84.
Power factor correction equipment was installed at the main plant substation and this brought the PF back to a much more acceptable 0,99.
Armed with the power factor and consumption data JTI were able to successfully apply for a tariff change from Ekhureleni. Mirkovic estimates that the tariff change on its own brought about a monthly consumption saving of 25% while the PF correction contributed to a 15% saving on the maximum demand portion of the utility bill.
New distribution board
As part of the distribution upgrade project, the 600 kVA transformer was decommissioned, leaving only the 2 MVA transformer. CHI supplied a new DB equipped with Magnum air circuit breakers and bus couplers, individual Socomec Diris A40 power monitors per circuit, a Cutler-Hammer DirectLOGIC 205 modular PLC and HMI. For a complete oversight of power consumption and distribution status, the PLC fitted to the new DB communicates with the PLC of the existing DB.
Other rationalisation benefits
“By carefully considering the immediate and future goals of the distribution system revamp we were able to decrease operating costs, improve health and safety compliance and implement integrated plant metering. The latter allows us to monitor energy consumption of individual plant areas, which improves costing accuracy.”
A subsequent project is planned to bring the integrated metering to the level of individual plant items, with the ultimate goal of knowing the cost of utilities per cigarette.
At present JTI is not using the system for load shedding, but all of the intelligence has been built into the CHI-supplied distribution board. As the level of data collection is increased and historical data is built up, load shedding rules will be developed and implemented.
JTI/E+H global initiative.
JTI is planning a global initiative with the help of Endress+Hauser to improve its recording of utilities (compressed air, electricity, steam and water) and non-manufacturing power consumption (airconditioners, lighting and small power). This will use E+H’s web-enabled eSight energy management software. E+H estimates that monitoring and targeting utilities can reduce site utility costs by between 5–20%.
Future expansion
Mirkovic says that new projects will result in the existing 2 MVA transformer being inadequate for plant needs. He is planning to replace the existing unit with a pair of high-efficiency oil-free 2 MVA units as the need arises.
Lessons learnt
Motion Control asked Mirkovic what lessons there were to be learnt from this project. “There is huge value in teamwork. This project was successful because the end-users, engineering team, consultants and suppliers all pulled together to achieve the project’s goals.”
“Originally our standard costing for utilities was mostly guesswork. We have a higher quality of information now and look forward to improving that further in the next project phase.”
For more information contact Rob Hare, CHI Control Components, +27 (0)11 824 7400, [email protected], www.chicontrol.co.za
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