This paper briefs the developmental course, manufacturing and applications, as well as future prospect of excitation systems of large size turbogenerators in China, emphatically expounds the advantages of seif-excitat...This paper briefs the developmental course, manufacturing and applications, as well as future prospect of excitation systems of large size turbogenerators in China, emphatically expounds the advantages of seif-excitation systems with potential source reetifiers and matters needing to be noted during dissemination and application of them.展开更多
GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correla...GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correlation dimension into account and promotes the computational efficiency prominently. Iterative SVD method is applied to remove the influence of noise on the result of correlation dimension. The faults of steam flow turbulence and oil film disturbance which occur in 600 MW Steam Turbine Generator are analyzed and whose correlation dimensions are computed. More distinct quantitative index than FFT is gained to distinguish two faults and it’s of little importance to apply correlation dimension to study the influence of various factors on steam flow turbulence fault for nonexistence of convergent floor in correlation integral curve, which presents a new way to learn the operational function of large capacity steam turbine generator and carry out comprehensive condition monitoring.展开更多
The dynamics of a turbogenerator are characterized by a nonlinearly interacting electrical and mechanical subsystems. Accurate and robust state reconstruction by an observer should be based on its nonlinear dynamic be...The dynamics of a turbogenerator are characterized by a nonlinearly interacting electrical and mechanical subsystems. Accurate and robust state reconstruction by an observer should be based on its nonlinear dynamic behavior. Linear and reduced order observers are undesired since intolerable error of state reconstruction may be expected especially if the operating conditions and/or the external disturbances are, as usual in modern power systems, extremely changed. The 2nd authors of this paper had published a methodical design of a full order nonlinear observer for turbogenerator systems and conducted its experimental validation on a 120 MVA and 1,000 MVA synchronous generators at Gud-Power Station in south Munich （Germany） and the Nuclear Power Station of Goesgen （Switzerland）. In this paper, the Lyapunov＇s stability is applied to the mechanical slow motion of nonlinear observer. A second order Lyapunov function is introduced. Based on the energy interpretations of its terms, the necessary and sufficient conditions for the asymptotic stability of this nonlinear observer are derived.展开更多
This paper presents some opportunities to improve feedwater system efficiency for industrial boilers, usually consisting of multistage centrifugal pumps driven by three-phase induction motors. There is abundant litera...This paper presents some opportunities to improve feedwater system efficiency for industrial boilers, usually consisting of multistage centrifugal pumps driven by three-phase induction motors. There is abundant literature on the efficiency in steam boilers. However, few deal exclusively with feedwater systems. The total horsepower in boiler feed pumps and the corresponding energy consumption estimated for Brazilian industries are as follows： 110.5 MWE of motor driven power and a yearly electricity consumption of 442 GWh for a population of 7,800 steam boilers, approximately. It is estimated that there can be an efficiency improvement in feedwater systems for industrial boilers of 30% on average. To a large extent, these opportunities reside in older boilers that are very common in the Brazilian industrial sector. The most common causes for the low efficiency of feedwater systems are： the control loop of the feedwater, oversized boilers and excessive operational pressure set. Sometimes, the boiler feedwater system can present more than one problem simultaneously. Any kind of solution involves some speed regulation, new pump and number of pumps. Each problem generation facilities were selected in which common inefficiencies cases, the improvement in efficiency can get to 37%. form of intervention in boiler feed pumps, such as： impeller trim, may have more than one solution. Three distinct industrial steam are present. The suggested solutions were analyzed. In these three展开更多
文摘This paper briefs the developmental course, manufacturing and applications, as well as future prospect of excitation systems of large size turbogenerators in China, emphatically expounds the advantages of seif-excitation systems with potential source reetifiers and matters needing to be noted during dissemination and application of them.
文摘GP algorithm of correlation dimension computation is ameliorated which overcomes the shortage of traditional one. Improved process of GP algorithm takes the influence of temporal correlative pairs of points on correlation dimension into account and promotes the computational efficiency prominently. Iterative SVD method is applied to remove the influence of noise on the result of correlation dimension. The faults of steam flow turbulence and oil film disturbance which occur in 600 MW Steam Turbine Generator are analyzed and whose correlation dimensions are computed. More distinct quantitative index than FFT is gained to distinguish two faults and it’s of little importance to apply correlation dimension to study the influence of various factors on steam flow turbulence fault for nonexistence of convergent floor in correlation integral curve, which presents a new way to learn the operational function of large capacity steam turbine generator and carry out comprehensive condition monitoring.
文摘The dynamics of a turbogenerator are characterized by a nonlinearly interacting electrical and mechanical subsystems. Accurate and robust state reconstruction by an observer should be based on its nonlinear dynamic behavior. Linear and reduced order observers are undesired since intolerable error of state reconstruction may be expected especially if the operating conditions and/or the external disturbances are, as usual in modern power systems, extremely changed. The 2nd authors of this paper had published a methodical design of a full order nonlinear observer for turbogenerator systems and conducted its experimental validation on a 120 MVA and 1,000 MVA synchronous generators at Gud-Power Station in south Munich （Germany） and the Nuclear Power Station of Goesgen （Switzerland）. In this paper, the Lyapunov＇s stability is applied to the mechanical slow motion of nonlinear observer. A second order Lyapunov function is introduced. Based on the energy interpretations of its terms, the necessary and sufficient conditions for the asymptotic stability of this nonlinear observer are derived.
文摘This paper presents some opportunities to improve feedwater system efficiency for industrial boilers, usually consisting of multistage centrifugal pumps driven by three-phase induction motors. There is abundant literature on the efficiency in steam boilers. However, few deal exclusively with feedwater systems. The total horsepower in boiler feed pumps and the corresponding energy consumption estimated for Brazilian industries are as follows： 110.5 MWE of motor driven power and a yearly electricity consumption of 442 GWh for a population of 7,800 steam boilers, approximately. It is estimated that there can be an efficiency improvement in feedwater systems for industrial boilers of 30% on average. To a large extent, these opportunities reside in older boilers that are very common in the Brazilian industrial sector. The most common causes for the low efficiency of feedwater systems are： the control loop of the feedwater, oversized boilers and excessive operational pressure set. Sometimes, the boiler feedwater system can present more than one problem simultaneously. Any kind of solution involves some speed regulation, new pump and number of pumps. Each problem generation facilities were selected in which common inefficiencies cases, the improvement in efficiency can get to 37%. form of intervention in boiler feed pumps, such as： impeller trim, may have more than one solution. Three distinct industrial steam are present. The suggested solutions were analyzed. In these three
