Replacement of DCS and ESD at Saudi Electricity Company's Power Plant No.9

Executive Summary

Customer profile

The Saudi Electricity Company (SEC) enjoys a monopoly on the generation, transmission, and distribution of electric power in the Kingdom of Saudi Arabia. The company operates numerous power plants throughout the country, including power plant No.9 (PP9), which is situated east of Riyadh, on the road to Dammam.

Summary of the project

PP9 has a total of six power blocks (A – F). Blocks A and B are combined cycle facilities and the remaining are simple cycle. SEC awarded a lumpsum turnkey project to Yokogawa Saudi Arabia Company (YKSA) to replace the control systems as well as the associated auxiliary equipment and common systems in Power blocks A and B. These power blocks are further segregated into sub-blocks A1, A2, B1 and B2 which are identical in design, and each of which have four gas turbines (GT), four heat recovery steam generators (HRSG), and one steam turbine (ST). Each of the GE Mark V Gas Turbines is of 80MW capacity while each of the GE Mark V Steam Turbines is of 120MW capacity. These power blocks were originally controlled by a Foxboro IA series DCS, and a Triconex safety system for the ESD application of the main inlet gas valve. Through this project, they were replaced by the CENTUM VP R5 DCS and the ProSafe-RS R3 safety integrated system. The scope of work included engineering, testing, supply, demolition of the existing DCS and ESD control systems, installation, commissioning, training, start-up of the power generation units, and resident engineer support for a 1 year warranty period.
Some of the highlights of the scope of work included the refurbishment of the main control room, the replacement of the mimic panels with fourteen 70 inch LED displays, the cut-over of 28,000+ hardwired IOs, and the provision of interfaces for the redundant linking to the DCS of 30+ subsystems that use different communication protocols.

 

The Challenges and the Solutions

Since the award of the project to Yokogawa in March 2015, every step forward involved both contractual and technical challenges, owing to the lumpsum turnkey nature of the project. As follows, we look at just a few of the technical challenges faced during the execution of this project.

Following a project kick-off meeting with the customer, a project team was established and fully geared up its activities to drive ahead the project. At the start of the project, very little was known about the intricacies that would be involved in replicating and converting from the existing software to Yokogawa’s DCS and SIS platform. The first challenge was to extract the project backup and configuration files from each of the UNIX-based FOXBORO workstations and engineering stations. This was not a simple copy and paste task as the workstations were a decade old and their floppy drives weren't working. Another team member within the same department who had prior experience with FOXBORO systems was brought in to salvage the situation. An expert freelancer was also quickly hired and sent to the site, where he with great difficulty was able to download the old files. 

Next came the challenge of reverse engineering. Yokogawa’s FOXBORO migration tool came in handy with segregating the data in the IO database and getting it into a shape suitable for an initial run, followed by the manual labor of structuring the IO database into a usable format. The project team made up of personnel from Yokogawa Middle East & Africa, Yokogawa India’s Global Delivery Center, and the 3rd party legacy systems expert also put in a lot of hard work to decode the blackbox and come out with the algorithms. After that the work was quite straightforward and easy.

The main control room with mimic panels (before replacement)

With the finished product taking shape, the engineering team back at office was busy giving their final touches to the generated logic and graphics in preparation for a full-fledged FAT. Concurrently, under the supervision of our engineers, the site contractor was identifying trenches, pulling cables, getting rid of old items, cutting, welding, cleaning, and so forth. The site activities were all meticulously planned in preparation for the much-anticipated installation and cutover activities.

Considering the peak load power requirements in summer, SEC had scheduled the shutdown in two phases. The 1st first phase of shutdown from November 2015 to March 2016 included the cut-over and commissioning of Block-A1, Block-A2 and Node-81 (Liquid fuel systems). The FAT was just a rehearsal. But the Cut-over and commissioning were a live performance. We were keeping our fingers crossed and hoping for the best to bring the units back to life again. Everyone had only one goal which was to synchronize the units to the grid and put back the power blocks to commercial operation. To everyone’s relief, the GTs were quickly synchronized to the grid one after the other with all the related auxiliaries being controlled from CENTUM VP DCS without much hassles. This bolstered the customer’s confidence in the capabilities of our team, the quality of our engineering, and the depth of our commitment, and with their good support we were able to easily put the STs back in service. The activities carried out during this first shutdown were a great success.

DCS marshalling panel after cut-over from FOXBORO

During the second phase of shutdown from October 2016 to February 2017, the cut-over and commissioning for sub-blocks B1 and B2, node 82 (fuel gas systems), the water treatment plant, 380KV substation, and the main control room (MCR) were carried out. Our team, which had been kept waiting during the summer of 2016, was faced with a bigger challenge this time due to the bigger scope and the ESD system cut-over. Unlike the FOXBORO DCS, the Triconex safety instrumented system could not be downloaded because the plant did not have a Tri-station. So, using the available documents in the customer’s library, our team built the SIS application logic from scratch for the ProSafe-RS system. The lessons learned and the rich experience gained during the first shutdown helped us get things on track in a short period of time. We were no longer novices in control system replacement jobs. The core task of commissioning the power generation units was given the highest priority, while the less urgent refurbishment of the MCR was planned towards the end of the shutdown schedule. The work done during the second shutdown was also a big success.

The refurbished MCR

More than a hundred personnel from SEC received extensive training on the CENTUM VP R5 DCS and ProSafe-RS R3 safety instrumented system. Tailor-made courses on engineering, maintenance, operation and system administration were planned in batches and scheduled to be conducted On-site for several weeks so as not to interfere with plant operations.
After completion of all project requirements and a one month reliability test, Yokogawa was issued a Final Completion Certificate (FCC) in May 2019. The subsequent one year warranty period concluded in May 2020. As mandated in the contract, a Yokogawa resident engineer was stationed at the PP9 site during the warranty period to keep watch on the systems. As a token of their appreciation, SEC sent us a letter applauding our years of hard work and the results of our efforts. It was teamwork and a job well done that everyone involved can cherish for years to come. When we called to thank the plant operation manager who was also the head of the project committee, he replied “You guys deserve it.” Our happiness knew no bounds, and project PP9 is yet another feather in Yokogawa Middle East & Africa (YMA)’s cap.