This paper presents a computer model for the probabilistic representation of wind farms generatio... more This paper presents a computer model for the probabilistic representation of wind farms generation for reliability studies, which can provide an annual estimation of energy production and calculate several performance indexes. The model combines the stochastic characteristics of wind speed with the operational information of the turbines, such as the failure and repair rates, representing the wind farm by a
This paper proposes a probabilistic approach for obtaining the security region that combines Reli... more This paper proposes a probabilistic approach for obtaining the security region that combines Reliability Evaluation with Voltage Security Assessment. The approach takes into consideration the probability of occurrence of the network contingencies using Monte Carlo simulation and provides visual information by means of nomograms of the security regions associated with different levels of risk of voltage violation. The computational details are presented for a parallel computing based implementation for on-line application. Results for the IEEE Reliability Test System under heavy and light loads are presented and compared with the deterministic nomograms.
One of the most important random variables to be considered in hydrothermal systems operation and... more One of the most important random variables to be considered in hydrothermal systems operation and planning models is river inflows, especially in countries with a very high penetration of hydro power plants. Usually inflows are represented by periodic autoregressive parametric models, assuming that they follow a log-normal distribution. This paper proposes the application of a non-parametric estimation method, called kernel density estimation, for the construction of an autoregressive model for river inflows that does not assume any specific distribution. The synthetic series generated by the proposed model tend to better reproduce the probability density of the historical time series. The model was applied to some hydrolological series of the Brazilian system, and its efficiency was demonstrated as well as some advantages over the conventional approach.
This paper presents a flexible object-oriented computational model for composite systems reliabil... more This paper presents a flexible object-oriented computational model for composite systems reliability evaluation based on Sequential and Non-Sequential Monte Carlo Simulation. The main focus of the model is in the representation of time varying components, such as the wind generation and the load. The modeling flexibility enables the representation of complex network components and the comparison of indices obtained by both sequential and non-sequential approaches. The results obtained with studies based on the IEEE RTS system demonstrate the applicability of the developed model and provide important conclusions about wind generation influence on power system reliability indices.
ABSTRACT This paper presents an integrated model for operation planning of electric power systems... more ABSTRACT This paper presents an integrated model for operation planning of electric power systems that considers the natural gas transport network and the modeling of the hydroelectric power plant reservoirs. Constraints on the reservoirs, on the production and transport of natural gas, and on the generation and transmission of electric power are considered. The model of the hydroelectric power plants is a deterministic linear model for short term analysis. The model of the natural gas transport system is based on the non-linear relationship between the gas flow and the pressure at the pipeline terminals. The electric network is modeled by a linear (DC) power flow. The objective of the integrated model is to minimize the cost of operation of the electric system, considering the transmission network constraints, the hydrological limitations of the reservoirs, and the natural gas network limits for supplying the thermoelectric plants.
This chapter presents a review of the main application areas of high performance computing in ele... more This chapter presents a review of the main application areas of high performance computing in electrical energy systems and introduces some results obtained with the implementation of parallel computing to some relevant problems encountered in the planning, operation and control of such systems. The research topics described in the paper are optimization of hydrothermal systems operation, tunning of multiple power system stabilizers, security constrained optimal power flow, composite reliability evaluation, dynamic security assessment, and distribution network reconfiguration. Most of the work described includes results obtained with tests conducted using actual models of electrical energy systems.
IEEE Transactions on Sustainable Energy, Jul 1, 2015
The purpose of this paper is to assess the impact of the integration of wind generation, together... more The purpose of this paper is to assess the impact of the integration of wind generation, together with small hydropower plants (SHPs), in the reliability of the power system. In order to preserve the characteristics of the time series of the variable energy sources (wind and river inflows) and the variable load, the analyses are based on the sequential Monte Carlo simulation. By calculating the reliability indices, we intend to evaluate how the uncertainty of wind energy production impacts on system planning, especially with the reduction of capacity of reservoirs associated with SHPs. We also intend to evaluate the existence of complementarity between wind and hydro-generation, or even between different wind generation and/or the load. Finally, we intend to analyze how the correlation between these energy sources can benefit the supply of the future foreseen demand.
... To determine the parameters Uk and λk of bus 6 of RTS, the total load of RBTS-Bus2 is connect... more ... To determine the parameters Uk and λk of bus 6 of RTS, the total load of RBTS-Bus2 is connected directly to bus 6 and a composite reliability model is used to calculate the indices LOLP (Loss of Load Probability) and LOLF (Loss of ... [7] LEITE, AP, BORGES, CLT, FALCÃO, DM ...
This paper presents a sensitivity analysis on the reliability of a hydroelectric plant with reser... more This paper presents a sensitivity analysis on the reliability of a hydroelectric plant with reservoir with respect to its storage capacity level. The comparison is made in probabilistic terms, using the sequential Monte Carlo simulation, which takes into account equipment failures, hydrological inflow scenarios and a load curve. The reliability evaluation was carried out for a generation system composed of just one hydro power plant supplying its respective load, considering five hypotheses of its storage capacity. In addition to the traditional reliability indices, it was also computed a reliability indicator, denoted by P95, which can be used as the “capacity value” to be issued to the hydro plant for commercial purposes. The analysis of the resulting annual reliability indexes shows the impact of reducing the storage capacity not only on the plant's “firm energy” but also on its capacity value attribute. Moreover, for all storage levels considered, the monthly values of P95 presented significant seasonal variation, which further confirms the importance of storage capacity or “regulating capacity” to ensure system reliability all over the year.
This paper reports on developments in the implementation of power system analysis applications in... more This paper reports on developments in the implementation of power system analysis applications in clusters of personal computers. Three applications are described: generation and transmission composite reliability evaluation; power system dynamic security analysis; and coordinated tuning of power system stabilizers using genetic algorithms. All applications were developed based on modelling techniques currently adopted in the power system industry and tested with realistic size power system models. The results indicate that this low cost computer system has great potential for practical use in the power utility environment
ABSTRACT This paper presents a methodology for parallelisation of the power systems composite rel... more ABSTRACT This paper presents a methodology for parallelisation of the power systems composite reliability evaluation using Monte Carlo simulation. A coarse grain parallelisation strategy is adopted, where the adequacy analyses of the sampled system states are distributed among the processors. An asynchronous parallel algorithm is described and tested on 5 different electric systems. The paper presents results of almost linear speedup and high efficiency obtained on a 4 node IBM RS/6000 SP distributed memory parallel computer.
This paper presents a computer model for the probabilistic representation of wind farms generatio... more This paper presents a computer model for the probabilistic representation of wind farms generation for reliability studies, which can provide an annual estimation of energy production and calculate several performance indexes. The model combines the stochastic characteristics of wind speed with the operational information of the turbines, such as the failure and repair rates, representing the wind farm by a
This paper proposes a probabilistic approach for obtaining the security region that combines Reli... more This paper proposes a probabilistic approach for obtaining the security region that combines Reliability Evaluation with Voltage Security Assessment. The approach takes into consideration the probability of occurrence of the network contingencies using Monte Carlo simulation and provides visual information by means of nomograms of the security regions associated with different levels of risk of voltage violation. The computational details are presented for a parallel computing based implementation for on-line application. Results for the IEEE Reliability Test System under heavy and light loads are presented and compared with the deterministic nomograms.
One of the most important random variables to be considered in hydrothermal systems operation and... more One of the most important random variables to be considered in hydrothermal systems operation and planning models is river inflows, especially in countries with a very high penetration of hydro power plants. Usually inflows are represented by periodic autoregressive parametric models, assuming that they follow a log-normal distribution. This paper proposes the application of a non-parametric estimation method, called kernel density estimation, for the construction of an autoregressive model for river inflows that does not assume any specific distribution. The synthetic series generated by the proposed model tend to better reproduce the probability density of the historical time series. The model was applied to some hydrolological series of the Brazilian system, and its efficiency was demonstrated as well as some advantages over the conventional approach.
This paper presents a flexible object-oriented computational model for composite systems reliabil... more This paper presents a flexible object-oriented computational model for composite systems reliability evaluation based on Sequential and Non-Sequential Monte Carlo Simulation. The main focus of the model is in the representation of time varying components, such as the wind generation and the load. The modeling flexibility enables the representation of complex network components and the comparison of indices obtained by both sequential and non-sequential approaches. The results obtained with studies based on the IEEE RTS system demonstrate the applicability of the developed model and provide important conclusions about wind generation influence on power system reliability indices.
ABSTRACT This paper presents an integrated model for operation planning of electric power systems... more ABSTRACT This paper presents an integrated model for operation planning of electric power systems that considers the natural gas transport network and the modeling of the hydroelectric power plant reservoirs. Constraints on the reservoirs, on the production and transport of natural gas, and on the generation and transmission of electric power are considered. The model of the hydroelectric power plants is a deterministic linear model for short term analysis. The model of the natural gas transport system is based on the non-linear relationship between the gas flow and the pressure at the pipeline terminals. The electric network is modeled by a linear (DC) power flow. The objective of the integrated model is to minimize the cost of operation of the electric system, considering the transmission network constraints, the hydrological limitations of the reservoirs, and the natural gas network limits for supplying the thermoelectric plants.
This chapter presents a review of the main application areas of high performance computing in ele... more This chapter presents a review of the main application areas of high performance computing in electrical energy systems and introduces some results obtained with the implementation of parallel computing to some relevant problems encountered in the planning, operation and control of such systems. The research topics described in the paper are optimization of hydrothermal systems operation, tunning of multiple power system stabilizers, security constrained optimal power flow, composite reliability evaluation, dynamic security assessment, and distribution network reconfiguration. Most of the work described includes results obtained with tests conducted using actual models of electrical energy systems.
IEEE Transactions on Sustainable Energy, Jul 1, 2015
The purpose of this paper is to assess the impact of the integration of wind generation, together... more The purpose of this paper is to assess the impact of the integration of wind generation, together with small hydropower plants (SHPs), in the reliability of the power system. In order to preserve the characteristics of the time series of the variable energy sources (wind and river inflows) and the variable load, the analyses are based on the sequential Monte Carlo simulation. By calculating the reliability indices, we intend to evaluate how the uncertainty of wind energy production impacts on system planning, especially with the reduction of capacity of reservoirs associated with SHPs. We also intend to evaluate the existence of complementarity between wind and hydro-generation, or even between different wind generation and/or the load. Finally, we intend to analyze how the correlation between these energy sources can benefit the supply of the future foreseen demand.
... To determine the parameters Uk and λk of bus 6 of RTS, the total load of RBTS-Bus2 is connect... more ... To determine the parameters Uk and λk of bus 6 of RTS, the total load of RBTS-Bus2 is connected directly to bus 6 and a composite reliability model is used to calculate the indices LOLP (Loss of Load Probability) and LOLF (Loss of ... [7] LEITE, AP, BORGES, CLT, FALCÃO, DM ...
This paper presents a sensitivity analysis on the reliability of a hydroelectric plant with reser... more This paper presents a sensitivity analysis on the reliability of a hydroelectric plant with reservoir with respect to its storage capacity level. The comparison is made in probabilistic terms, using the sequential Monte Carlo simulation, which takes into account equipment failures, hydrological inflow scenarios and a load curve. The reliability evaluation was carried out for a generation system composed of just one hydro power plant supplying its respective load, considering five hypotheses of its storage capacity. In addition to the traditional reliability indices, it was also computed a reliability indicator, denoted by P95, which can be used as the “capacity value” to be issued to the hydro plant for commercial purposes. The analysis of the resulting annual reliability indexes shows the impact of reducing the storage capacity not only on the plant's “firm energy” but also on its capacity value attribute. Moreover, for all storage levels considered, the monthly values of P95 presented significant seasonal variation, which further confirms the importance of storage capacity or “regulating capacity” to ensure system reliability all over the year.
This paper reports on developments in the implementation of power system analysis applications in... more This paper reports on developments in the implementation of power system analysis applications in clusters of personal computers. Three applications are described: generation and transmission composite reliability evaluation; power system dynamic security analysis; and coordinated tuning of power system stabilizers using genetic algorithms. All applications were developed based on modelling techniques currently adopted in the power system industry and tested with realistic size power system models. The results indicate that this low cost computer system has great potential for practical use in the power utility environment
ABSTRACT This paper presents a methodology for parallelisation of the power systems composite rel... more ABSTRACT This paper presents a methodology for parallelisation of the power systems composite reliability evaluation using Monte Carlo simulation. A coarse grain parallelisation strategy is adopted, where the adequacy analyses of the sampled system states are distributed among the processors. An asynchronous parallel algorithm is described and tested on 5 different electric systems. The paper presents results of almost linear speedup and high efficiency obtained on a 4 node IBM RS/6000 SP distributed memory parallel computer.
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