A typical feature of modern generator-drive steam turbines for industrial applications in the power range up to 60 MW is the use of a gearbox between the steam turbine and the generator. The technical concept of Siemens’ SST-400 turbine, which is a modern and at the same time well-proven product, is environmentally-friendly due to the high efficiency, and the decreased materials and fabrication energy demand. In this paper the SST-400 is presented by references from Thailand, Malaysia and Turkey.

The traditional world of power generation in the range of 150 to 250 MW is changing. We can recognize the following trends:

Liberalization/deregulation of the electricity market continues to expand in many parts of the world. This requires that power producer owners and operators deliver electricity more efficiently and at competitive pricing. In parallel with these market demands, the operation of the complete power plant – turbine, generator, boiler and auxiliaries – must improve reliability, availability and utilization/efficiency.

One way to achieve the objective of a flexible and short termed outage planning and to reduce the transactional costs is to establish Service Contracts between the utilities on the one side and the manufacturers on the other. These tailor made contracts should be the basis to leave the transactional business behind and to enter value based and success depending business models or contracts. Critical factors for the success were the alignment of the objectives and the definition of benchmark matrices (Score Cards) to measure the level of success. The range of this Strategic Contracts can vary from simple parts availability programs or Operating Plant Service Agreements (OPSA) to Long Term Programs (LTP) with risk sharing elements and the value based payment mentioned above.
In addition these aims could be achieved more efficiently by using intelligent condition monitoring strategies for the power plant and its key components using a supervisory on-line diagnostic system. The use of comprehensive on-line data acquisition, internet data transmission systems, task-related data analysis and an expert background knowledge base at newly founded Remote Diagnostic Center enable detailed diagnosis of the actual plant condition.

A reliable source of low-cost electricity is fundamental to a healthy economy. The current market supports both the development of new generating resources and the retrofitting of the existing infrastructure to meet the increased electrical demands. These technology retrofit solutions represent an opportunity for generating companies to quickly and cost-effectively improve their competitive position by improving the operation, performance and reliability of existing equipment. This paper describes the design and the results of the Steam Turbine Replacement Components that were supplied by Siemens Power Generation to Dairyland Power Cooperative.

Turbine technologies available for modernization of existing units, as well as replacement steam paths, are:

Power plant market requirements have changed in recent years. The tendency for highly flexible and efficient power plants with long revision intervals, life times ≥200,000h as well as low investment costs have resulted in an increased effort in the improvement of design and materials. One possible way to meet high efficiency requirements is to install sub-critical steam power plants with live steam temperatures of T ≥565 °C and an optimized steam cycle path. As a result, new challenges have arisen for the design of a two cylinder steam turbine line for a capacity up to 700 MW.

Turbine and generator rotors undergo high stresses and, from a safety aspect, are the most significant components of a turbine generator system. Depending on the appropriate operating temperatures, the shafts can be fabricated out of low/high alloy heat resistance material or of low alloyed, highly toughened material for low pressure application.