Regression Modelling Estimation of Marine Diesel Generator Fuel Consumption and Emissions

This study aims to estimate the fuel consumption of marine diesel generators onboard. Objective technical specifications and operational data on the ship\u27s power generating plants and port calls were collected from an oceangoing oil/chemical tanker and used to develop the mathematical model of the plant in the Python and MATLAB environment. The model consists of alternators, prime movers and load distributions of the ship’s power generating plant and provides information on fuel consumption in metric tons calculated based on hours of operation and specific fuel consumption data. Regression models have helped predict future fuel consumption for the plant and the optimal model for the dataset was identified by comparing four different algorithms. As the results have shown the Ordinary Least Squares Regression to be optimum, it was used to make one, five, and ten-year predictions. The predictions for one-year, five-year, and ten-year periods are 4,322,436, 10,684,860, and 18,615,472 t respectively. The selected model predicts fuel consumption with R2 of 0.999, MAE of 3.932, and RMSE of 2.935. Fuel consumption predictions facilitated plant emission calculation

Adaptive Parameter Estimation of Power System Dynamic Models Using Modal Information

Knowledge of the parameter values of the dynamic generator models is of paramount importance for creating accurate models for power system dynamics studies. Traditionally, power systems consists of a relatively limited numbers of large power stations and the values of generator parameters were provided by manufacturers and validated by utilities. Recently however, with the increasing penetration of distributed generation, the accuracy of these models and parameters cannot be guaranteed. This thesis addresses the above concerns by developing a methodology to estimate the parameter values of a power system dynamic model online, employing dynamic system modes, i.e. modal frequencies and damping. The dynamic modes are extracted from real-time measurements. The aim of the proposed methodology is to minimise the differences between the observed and modelled modes of oscillation. It should be emphasised that the proposed methodology does not aim to develop the dynamic model itself but rather modify its parameter using WAMS measurements. The developed methodology is general and can be used to identify any generator parameters., However, thesis concentrates on the estimation of generator inertia constants. The results suggest that the proposed methodology can estimate inertias and replicate the dynamic behaviour of the power system accurately, through the inclusion of pseudo-measurements in the optimisation process. The pseudo-measurements not only improves the accuracy of the parameter estimation but also the robustness of it. Observability, a problem when there are fewer numbers of measurements than the numbers of parameters to be estimated, has also been successfully tackled. It has been shown that the damping measurements do not influence the accuracy and robustness of generator inertia estimation significantly

Sensitivity bond graphs

A sensitivity bond graph, of the same structure as the system bond graph, is shown to provide a simple and effective method of generating sensitivity functions of use in optimisation. The approach is illustrated in the context of partially known system parameter and state estimation

Utjecaj zasićenja na identifikaciju parametara sinkronog generatora u pogonu

This paper discusses on-line estimation of rotor body parameters of the synchronous hydro-generator under saturated condition. A new model of the saturated synchronous salient-pole machine, based on the saturated synchronous inductances which are estimated from measured steady-state operating data, is presented. Using this model the excitation disturbance responses of the saturated synchronous generator are simulated. The synthetic data, obtained by these simulations, are used for testing the estimation procedures and models for both the field and damper winding under saturated condition. It is shown that, by comparison with unsaturated condition, estimation models become more complex and estimation procedures are generally less robust. Particularly, when the damper winding is under consideration, it has been shown that the estimation process gives wrong parameters if the machine saturation characteristic obtained by measurements is not perfectly accurate. Results of measurements performed on the 34 MVA generator in the Peruca hydroelectric power plant in Croatia are presented. The paper also discusses the influence of the measurement noise on the estimation process.U radu se razmatra “online” estimacija rotorskih parametara sinkronog hidrogeneratora u uvjetima zasićenja. Razvijen je jedan novi model zasićenog sinkronog stroja s istaknutim polovima koji se temelji na mjerenjima sinkronih reaktancija u stacionarnom stanju. Na temelju tog modela simulirani su odzivi zasićenog sinkronog generatora pri promjeni uzbudnog napona. Odzivi dobiveni simulacijom korišteni su za testiranje estimacijskih postupaka i modela u uvjetima zasićenja, kako za uzbudni tako i za prigušni namot. U usporedbi s nezasićenim stanjem, pokazano je da estimacijski modeli postaju kompleksniji dok su estimacijski postupci manje robusni. Napose, kada se razmatra prigušni namot, pokazano je da estimacijski postupak daje pogrešne parametre ako karaketristika zasićenja stroja nije potpuno točna. Prikazani su rezultati mjerenja dobiveni na generatoru snage 34 MVA u hidroelektrani Peruća. U radu se također razmatra utjecaj mjernog šuma na estimacijski postupak

Development of a converter for grid-tied and isolated operation of an interior permanent magnet synchronous generator, coupled to a twin-shaft gas turbine

South Africa’s overreliance on coal fired power generation has led to the government’s commitment to diversifying the country’s energy mix. Gas turbine generators are poised to play a larger role in South Africa’s energy mix, due to the country’s abundance in natural gas reserves. Therefore, there is a need to developed gas turbine emulation systems to investigate how this transition is to be implemented and to discover new efficient ways to generate power through gas turbines. This thesis presents the development of a twin-shaft gas turbine emulator. A DC-machine that accepts both torque and speed references is used to emulate the behaviour of the gas turbine according to a modified Rowen gas turbine model. The emulator is coupled to a 1.5kW interior permanent magnet synchronous generator (IPM). The power density of a DC-machine is significantly lower than that of a gas turbine of the same rating. Thus, the DC-machine is rated at double the rating of the IPM to overcome the high inertia it has when compared to a gas turbine of the same rating. This means that the DC-machine can produce large toques to successfully emulated the dynamic behaviour of the gas turbine. A maximum error 2.5% in the emulation of the gas turbine’s speed is reported. A two-level active converter is used to compare control strategies for an IPM. Ninety-degree torque angle (NTA) control, maximum torque per ampere (MTPA) control and unity power factor (UPF) control are compared for performance. The UPF and MTPA control result in the lowest and second lowest DC-link utilisation respectively when compared to NTA control. This is due to a negative d-axis current component as opposed to a zero d-axis current component in the case of NTA control. It is also concluded that to achieve a high power factor and torque development, a negative d-axis current component is required. UPF and MTPA control perform well in both categories, with UPF control and MTPA control resulting in the highest power factor and developed torque respectively. A fourth control strategy that maximises the efficiency of the IPM is developed experimentally. The maximum efficiency (ME) control strategy minimises mechanical, core, windage and conduction losses. It also results in near unity power factor and near maximum developed torque. A nonconventional control structure that involves control of the DC-link from the generatorside converter is presented. This frees the outer-loop control of load-side converter to regulate voltage across the load when the system is supplying power to an isolated load. This control structure also allows the grid-side converter to employ reactive power compensation, without having to regulate the DC-link voltage at the same time. In doing so, large grid currents are avoided. A recursive least squares (RLS) algorithm is used to separate negative and positive sequence current components during grid voltage unbalance. A method to minimise the presence of negative sequence components in the load current is presented and implemented successfully in an experiment