Multinational technology conglomerate Siemens Energy is upgrading the human-machine interface (HMI) systems on the generation units at State-owned power utility Eskom’s Camden coal-fired power station, near Ermelo, Mpumalanga.

The power station’s final unit was returned to service in 2008 after being mothballed for almost 20 years. It was the first of three recom- missioned power stations to return to service in South Africa, which Siemens says was the fastest way to add new capacity to Eskom’s grid, compared with building new power stations, to tackle the country’s power supply deficit.

“The HMI migration upgrade project began in February 2011 and is likely to be completed in December 2014,” says Siemens Camden power station project manager Shikrant Agre.

He notes that the upgrade is necessary to secure the plant from any future system obsolescence and to add to the plant’s life expectancy.

“The upgrade is part of the general plant life cycle management and keeping the control system technologically up to date,” says Agre.

The installed Siemens Power and Process Automation (SPPA) system, SPPA-T2000 HMI, is being replaced with the latest SPPA-T3000 HMI system, which Agre says will never become obsolete.

“This means that in future Eskom will not need to perform a major refurbishment with new engineering,” he says, noting that the added features include increased ease of handling, operator-specific graphic features, advanced access control and increased online availability of plant historical data.

“The first three generation units have successfully been completed and the balance of the units will be completed over the next 12 to 18 months,” he says.

The SPPA T3000 system is designed to perform all power plant automation tasks, including turbine control, boiler control, balance of plant and the integration of third-party systems, says Siemens instrumentation and electrical director Chris Waddicor.

“At Camden, this implementation step only involves the HMI replacement – in future, the possibility to completely migrate the automation system level to a full SPPA-T3000 solution inclusive of the a fully inte- grated turbine control and associ- ated failsafe protections systems could be considered,” he adds.

Benefits of the system, which Waddicor says allow for the future introduction of features existing today, in development or still in the pipe line, include setting benchmarks in controls, easy handling to support operators and plant engineers, plant information handling, increased remote monitoring facilities and expert systems.

“The system features are designed to make the activities of operators, maintenance personnel and engineers intuitive. “This results in an efficient operation and engineering mode to help with sound decision-making and flawless change during plant operation,” he explains.

Agre notes that the simplified system architecture also eliminates the need for subsystems that were previously required in traditional control systems structures, which is achieved through the SPPA-T3000 embedded component services features.

The main challenge Siemens has faced during the project thus far is ensuring that the upgrade is completed with no, or minimum, disturbances to the units which are being worked on.

“Thus far, we have been able to carry out the project with minimal disturbances,” notes Agre.

All eight coal-fired units at the power station are operational, adding 1 520 MW of generating capacity to the country’s national grid.

Waddicor says Siemens was involved in the return to service of the Camden power station and Eskom’s 1 000 MW Komati power station, where the last unit is presently planned for com- pletion this year.

“We have also been involved in refurbishments at other Eskom power stations in the country and in neighbouring Zimbabwe and Botswana,” he adds.

During the return to service of the Camden power station, Siemens’ scope of work was the complete refurbishment of the control and instrumentation systems for Units 1 to 8, as well as the bulk of the common plant. The company was also involved in the turbine and generator refur- bishments.

The company is, to date, also responsible for maintenance on the running units.

“This service began during the original commissioning time, around 2004,” says Agre.

Siemens has also invested about R8-million in the Power Academy, which was launched in Witbank in the second quarter of 2012, to provide intensive control and instrumentation training for people in the industry across South-east Africa.