Improvement of controllability by upgrading the existing turbine’s mechanical governors to electronic governorsIn order to replace the aging mechanical governor controls appropriately, Yokogawa and its partner companies carefully studied the drawings written in Russian and Mongolian and the existing facilities, and repeatedly consulted TPP4 staff. As a result, the team decided to renew the entire governor equipment. In addition to designing and delivering mechanical equipment such as cylinders, actuators, control oil filters, turbine protection devices, speed sensors, and vibration sensors, it was decided to modify or replace peripheral equipment and install suitable new equipment. The CENTUM VP was installed as the control and protection system, and the turbine governor was successfully upgraded to electronic governors, thus improving controllability. Automatic turbine operation by refurbishing existing turbine controls and instrumentation equipmentTo automate turbine operation, the existing analog control system along with instrumentation equipment such as pressure transmitters, valves and analyzers required for automation were upgraded, and monitoring and control were achieved by the CENTUM VP DCS. The control panels were set up in remote I/O houses newly installed on site, and optical cables were used to integrate the Vnet/IP control network. This resolved the constraints on installation location and allowed the cable materials and cabling work to be optimized. Furthermore, in addition to normal real-time plant monitoring and control, Yokogawa installed Exaquantum, a software system that enables centralized analysis of operational data, and Plant Resource Manager (PRM), a software system that enables streamlined field equipment maintenance. These tools helped improve plant operations and streamline facility maintenance by leveraging the centralized plant information. For plant monitoring and control, apart from the central control room, similar monitoring and control screens were installed adjacent to the individual turbines, enabling both on-site staff and staff in the central control room to share the same information via identical screens and communicate more effectively. Provision of a training environment with a simulator for seamless transition after renewalJust like in Phases 1 and 2, a DCS simulator for turbine control was introduced in Phase 3 as well, and multiple training sessions were conducted by skilled engineers to enable a smooth transition of operations, from the existing analog control system to the CENTUM VP.• Automate turbine operation by refurbishing the existing turbine • Provide a training environment with a simulator for seamless With this background, the main requirements of the customer were as follows:• Improve controllability by upgrading the existing turbines’ mechanical governors to electronic governorscontrols and instrumentation equipmenttransition after renewalOriginal mechanical governorsystems (MHC, or “mechanical governors”) to electro-hydraulic control systems (EHC, or “electronic governors”). It was necessary to grasp the current situation through repeated discussions with TPP4, and to analyze appropriate upgrade proposals and specifications.28The ChallengesFor all six turbines, most of the existing mechanical governors, control system, and instrumentation equipment had been in use since the plant was built in the 1980s and had deteriorated significantly. There were frequent abnormalities due to equipment malfunctions, as well as turbine emergency shutdowns from time to time due to erroneous manual operations, hindering the stable supply of electricity and heat, which is the ultimate purpose of TPP4. Furthermore, most of the equipment had been made in the former Soviet Union and it was difficult to obtain and replace parts for maintenance.The SolutionsThis project encompassed a broad range of mechanical modifications and instrumentation equipment upgrades, including upgrades of the existing mechanical-hydraulic control Phase 3: Turbine Control ModernizationExecutive SummaryEven after the successful completion of the Phase 1 and 2 projects, TPP4 still suffered serious problems due to the original turbine control systems and mechanical governing systems. The Mongolian government decided to execute a project to modernize the turbine controls and operation of Units 1–6 using an official development assistance (ODA) loan, following the successful improvement of the boiler control system. Yokogawa delivered control systems and replaced turbine governing systems and field instrumentation for six steam turbines.Ulaanbaatar TPP4 / Mongolia
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