Duke Energy is one of the largest electric power holding companies in the United States, supplying and delivering electricity to approximately 7.4 million U.S. customers. With their multiple facilities combined, Duke has 52,700 megawatts of electric generating capacity. Keeping such a hungry power grid running without any hiccups is a huge challenge for power plant operators. In a power plant, mistakes can not be made - hundreds of thousands of businesses, residents, hospitals, and institutions are relying on power to operate.

In collaboration with Stellar Energy, Sun State Systems built a 9-panel package system to control power plant operations at one of Duke Energy's power generation facilities. PLCs (Programmable Logic Controllers) were used to create a solution that could be reprogrammed and modified at ease. Duke Energy's control systems work together through all stages of generation and exchange data with the power plant control center to alert operators of potentially dangerous circumstances and system malfunctions.

Duke Energy chose to use PLCs because of their many advantages:

• Flexibility: One single Programmable Logic Controller can easily run many machines.
• Correcting Errors: In the old days, with wired relay-type panels, any program alterations required time for rewiring of panels and devices. With PLC control any change in circuit design or sequence is as simple as retyping the logic. Correcting errors in a PLC is extremely easy and cost effective.
• Space Efficient: Today's Programmable Logic Control memory is getting bigger and bigger this means that we can generate more and more contacts, coils, timers, sequencers, counters and so on. We can have thousands of contact timers and counters in a single PLC. Imagine what it would be like to have so many things in one panel. That would be a HUGE enclosure!
• Low Cost: Prices of PLCs vary from few hundreds to few thousands. This is nothing compared to the prices of the contact and coils and timers that you would pay to match the same things. Add to that the installation cost, the shipping cost and so on.
• Testing: A PLC program can be tested and evaluated in a lab. The program can be tested, validated and corrected saving very valuable time and allowing easy plug and play in the field.
• Visual observation: When running a PLC program a visual operation can be seen on the screen. Hence troubleshooting a circuit is really quick, easy and simple.