Simulators for power plants can be used for many different purposes, like training for operators or for adjusting control systems, where the main objective is to perform a realistic behaviour for different operating conditions of the power plant. Due to an increased amount of variable energy sources in the power system, the role of the operators has become more important. It can therefore be very valuable for the operators to try different operating conditions like island operation. The aim of this thesis is to model the power system of a general combined-cycle power plant simulator. The model should contain certain components and have a realistic behaviour but on the same time be simple enough to perform simulations in real time. The main requirements are to simulate cold start, normal operation, trip of generator, a controlled change-over to island operation and then resynchronisation. The modelling and simulations are executed in the modelling software Dymola, version 6.1. The interface for the simulator is built in the program LabView, but that is beyond the scope of this thesis. The results show a reasonable performance of the power system with most of the objectives fulfilled. The simulator is able to perform a start-up, normal load changes, trip of a generator, change-over to island operation as well as resynchronisation of the power plant to the external power grid. However, the results from the changing-over to island operation, as well as large load losses during island operation, show an unreasonable behaviour of the system regarding the voltage magnitude at that point. This is probably due to limitations in calculation capacity of Dymola, and the problem has been left to further improvements due to lack of time. There has also been a problem during the development of a variable speed regulated induction motor and it has not been possible to make it work due to lack of enough knowledge about how Dymola is performing the calculations. Also this problem has been left to further improvements due to lack of time.

This thesis covers the modelling of a Heat Recovery Steam Generator (HRSG) in a Combined Cycle Power Plant(CCPP). This kind of power plant has become more and more utilized because of its high efficiency and low emissions. The HRSG plays a central role in the generation of steam using the exhaust heat from the gas turbine. The purpose of the thesis was to develop efficient dynamic models for the physical components in the HRSG using the modelling and simulation software Dymola. The models are then to be used for simulations of a complete CCPP.The main application is to use the complete model to introduce various disturbances and study their consequences inthe different components in the CCPP by analyzing the simulation results. The thesis is a part of an ongoingdevelopment process for the dynamic simulation capabilities offered by the Solution department at SIT AB. First, there is a theoretical explanation of the CCPP components and control system included in the scope of this thesis. Then the development method is described and the top-down approach that was used is explained. The structure and equations used are reported for each of the developed models and a functional description is given. Inorder to ensure that the HRSG model would function in a complete CCPP model, adaptations were made and tuning was performed on the existing surrounding component models in the CCPP. Static verifications of the models are performed by comparison to Siemens in-house software for static calculations. Dynamic verification was partially done, but work remains to guarantee the validity in a wide operating range. As a result of this thesis efficient models for the drum boiler and its control system have been developed. An operational model of a complete CCPP has been built. This was done integrating the developed models during the work with this thesis together with adaptations of already developed models. Steady state for the CCPP model is achieved during simulation and various disturbances can then be introduced and studied. Simulation time for a typical test case is longer than the time limit that has been set, mainly because of the gas turbine model. When using linear functions to approximate the gas turbine start-up curves instead, the simulation finishes within the set simulation time limit of 5 minutes for a typical test case.

Abstract In recent years, domestic energy policy has continuously changed, especially, after a liberalization of electric power market opened, resulting into the power industry proprietor expected to has a stable electric power supply systems, high power generation, high thermal efficiency and low heat rate. They will consistently devise a way to propose a strategy of improved or enhanced in the light of a competitive footstone for electric force market. About 90% worldwide and 65% domestic electricity are generated by the thermal power plants, where the energy source is obtained from burning the fossil fuels. Therefore, Increasing the power generation capacity of thermal power plants will substantially raise to the percent reserve margin of to be smaller than 12% over the years. In Taiwan, the ambient temperature is always higher than 30oC at summer. When gas turbine has operated during peak, gave rise to deteriorate its power generation capability and often actually generated power lower 10% than based on a design condition of ISO 15oC. This study adopts a way which is not same as conventional method increased power generation capability of the thermal power plants. In other word, reducing the inlet air temperature to gas turbine, it will increase the air flow mass rate and the generated-power capacity. By means of EPRI Gate Cycle Software constructing a typical combined-cycle power plant, at the same time, to simulate and to search out an effective operating control strategy for the power plant with GTIAC. Furthermore, applying the electric chiller and the absorption chiller to combined-cycle power plant as an inlet air cooling system use thermodynamic and engineering analysis to discuss an extent of energy utilizing, the valuability of energy application, to access the economic effect of investing equipment to acquire an optimal balance point. Selecting the inlet air temperature 15oC,10oC and comparing the thermal performance of electric chiller with that of absorption chiller. Then, proposing a feasible suggestion to treat as an important reference criteration of improving present power GENSET and planning to install a thermal power plant for the electric power proprietor.

This thesis proposes a method and develops a model for the participation of a combined cycle power plant to power system frequency control. Through the period of integration to the UCTE system, (Union for Coordination of Transmission of Electricity in Europe) frequency behavior of Turkey&rsquo / s grid and studies related to its improvement had been a great concern, so is the reason that main subject of my thesis became as &ldquo / Power System Frequency Control&rdquo / . Apart from system-wide global control action (secondary control) / load control loops at power plants, reserve power and its provision even at the minimum capacity generation stage, (primary control) are the fundamental concerns of this subject. The adjustment of proper amount of reserve at the power plants, and correct system response to any kind of disturbance, in the overall, are measured by the quality of the frequency behaviour of the system. A simulator that will simulate a dynamic gas turbine and its control system model, together with a combined cycle power plant load controller is the outcome of this thesis.

The steel manufacturing industry is one of the largest emitters of CO2, accounting for upwards of 8.8% of all anthropogenic CO2 emissions. The governments are charging taxes on CO2 emissions, which incentivize the industry to further reduce CO2 emissions. At present, much of the CO2, produced in the steel manufacturing process occurs as a result of coke oven and blast furnace gas by-products. As such, two major strategies have been proposed to reduce steel-manufacturing-related CO2 emissions: producing more electricity via optimized combined cycle power plants (CCPP), and converting off-gas by-products into methanol (CBMeOH). The present research consists of an economic and environmental analysis of the status quo, CCPP, and CBMeOH systems for five locations: Ontario, the USA, Finland, Mexico, and China. The economic analysis considered factors such as carbon tax, electricity price, methanol price, electricity carbon intensity, power purchasing parity, and income tax. In the CCPP process, desulphurization is conducted using ProMax with MDEA as the solvent, while the CBMeOH process uses a membrane to separate the bulk H2S, with organic sulfurs such as thiophene being removed via CO2+steam reforming and middle-temperature removal. The results of the economic analysis revealed the CBMeOH plant to be the most profitable in Ontario, the USA, China, and Mexico, while the CCPP system was shown to be the most profitable in Finland. The environmental analysis was conducted using the TRACI, CML-IA, ReCiPe2016, and IMPACT2002+ tools in SimaPro V9, with the results showing the CBMeOH system to be the most environmentally option in Ontario, Finland, and China, and the CCPP system as the most environmentally friendly option in the USA and Mexico. / Dissertation / Doctor of Philosophy (PhD)