Power systems
Mehrdad Manshor; Mahmood Joorabian; Afshin Lashkarara
Abstract
Power management in microgrids is a major challenge due to its low total inertia and capacity. The lower the microgrid generation capacity is, the higher the share of each generation unit in total power will be, and the higher the frequency deviation in less time will be when an outage occurs. So, preventive ...
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Power management in microgrids is a major challenge due to its low total inertia and capacity. The lower the microgrid generation capacity is, the higher the share of each generation unit in total power will be, and the higher the frequency deviation in less time will be when an outage occurs. So, preventive actions can be more reasonable and affordable than corrective actions for microgrid power and frequency control. In this regard, a new primary frequency response-constrained unit commitment model is presented here to prevent excessive frequency deviations by more commitment of higher inertia power plants and more contribution of renewable energy resources or energy storage systems’ fast inertia response. To have a mixed-integer linear programming model, the primary frequency response constraints are linearized. The model is solved by the combination of two commercial solvers named MOSEK and YALMIP in the MATLAB 2018 environment. The proposed model is examined on a real isolated microgrid (an island). The results show that by activating the primary frequency support of distributed energy resources, the power can be managed with lower costs because there will be less need to start up fast (and expensive) gas turbine generation units. In addition, although comparing the model with others shows the more expensive management procedure, better frequency stability is obtained in contingencies.
Power systems
Seyed Arman Shirmardi; Mahmood Joorabian; Hassan Barati
Abstract
This paper presents microgrid (MG) operation constrained to the reliability, flexibility, and environment indices in the presence of distributed generations (DGs) and energy storage systems (ESSs). The proposed scheme minimizes the total expected operating cost of MGs and DGs. It is also subject to alternating ...
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This paper presents microgrid (MG) operation constrained to the reliability, flexibility, and environment indices in the presence of distributed generations (DGs) and energy storage systems (ESSs). The proposed scheme minimizes the total expected operating cost of MGs and DGs. It is also subject to alternating current (AC) power flow equations of MGs, constraints of operation, reliability, and flexibility in MG, and operation model of power sources and storage devices. Stochastic programming is incorporated to model uncertainties of load, energy price, the active power of renewable energy generation, availability of MG equipment, sources, and storage devices. Following on, a hybrid solver formed by combining artificial bee colony (ABC) and sine-cosine algorithm (SCA) is adopted to achieve the optimal solution with approximate conditions of unique ultimate response. Eventually, the suggested scheme is implemented on a 69-bus radial MG, where the numerical results confirm the capability of the scheme in improving the operation, reliability, flexibility, and environment status of the MG.
Power systems
Hojatolah Makvandi; Mahmood Joorabian; Hassan Barati
Abstract
The present study introduces a new extensive-area ANFIS (Adaptive Neuro-Fuzzy Interface System)-based method to detect wide area instability and control the time of controlled islanding execution within power systems. The ANFIS parameters are optimized by the PSO method to increase the method’s ...
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The present study introduces a new extensive-area ANFIS (Adaptive Neuro-Fuzzy Interface System)-based method to detect wide area instability and control the time of controlled islanding execution within power systems. The ANFIS parameters are optimized by the PSO method to increase the method’s accuracy at various disturbances and loading circumstances. In addition, to take various stability margins within the areas into account, a novel parallel ANFIS network (P-ANFIS) is implemented in which a distinct ANFIS is allocated for every nearby area. Extended off-line studies are performed to train ANFIS to respond in real-time accurately based on the selected wide area input signals. These parameters are monitored continuously through a wide area measurement system (WAMS) and the proposed P-ANFIS starts to assess the stability between related areas in real-time in the case of potentially unstable oscillations. Once an unstable oscillation is detected, the islanding command is transmitted to perform the controlled islanding scheme. The suggested technique is used in an IEEE 39 bus power system and its performance is demonstrated at different disturbances in terms of both speed and accuracy. It is found that the suggested ANFIS-based technique can determine islanding requirement and its time of execution properly at different disturbances.
Power systems
Mahyar Abasi; Mahmood Joorabian; Alireza Saffarian; Seyyed Ghodratollah Seifossadat
Abstract
Generalized Unified Power Flow Controller (GUPFC) is a member of the flexible alternating current transmission system (FACTS) devices family that operates based on voltage source converter (VSC) and is known as the most efficient FACTs device. GUPFC can control the voltage of one bus and the active and ...
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Generalized Unified Power Flow Controller (GUPFC) is a member of the flexible alternating current transmission system (FACTS) devices family that operates based on voltage source converter (VSC) and is known as the most efficient FACTs device. GUPFC can control the voltage of one bus and the active and reactive power flows on at least two transmission lines with equal voltage levels. This paper presents the mathematical modeling of power injection by GUPFC for the first time. Besides, the accurate design and details of the control system for series and shunt converters of a GUPFC, along with a new mathematical function for pulse generation based on a 48-pulse VSC when the GUPFC is placed in the middle point of a parallel transmission line, are presented in this study. The power injection modeling introduced in this paper is very useful and efficient in Newton-Raphson power flow studies and in modeling different parts of the control system and power electronics converter in dynamic and transient studies. The modeling is implemented in MATLAB/Simulink for a 400 km, 230 kV, and 60 Hz nominal frequency double-circuit transmission line. The satisfactory results provided in the simulations section of the paper verify the validity and accurate performance of the proposed model.
Power systems
Jamshid Barati; Seidghodratollah Seifossadat; Mahmood Joorabian
Abstract
Distance relays calculate the path impedance between the fault point and the relay location by sampling the voltage and current at the relay location. By using the ratio of the impedance estimated by the relay to the impedance of the line where the relay is installed, the location of the fault can be ...
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Distance relays calculate the path impedance between the fault point and the relay location by sampling the voltage and current at the relay location. By using the ratio of the impedance estimated by the relay to the impedance of the line where the relay is installed, the location of the fault can be estimated by a distance relay. However, several factors influence the estimated impedance and proper operation of distance relays. The most important of these factors is the resistive fault occurrence, which results in an increase in the impedance and deviation of the impedance estimated by the relay as well as causes relay under-reach. Therefore, in the present study, an adaptive method is proposed to modify the protection zones of distance relays settings under different operating conditions and resistive fault occurrence. Furthermore, the adaptive distance protection of transmission lines, wind farm collector lines and the protection coordination of the relays in these lines are investigated. In this method, an adaptive coefficient is added to the conventional characteristics of distance relays to improve the accuracy and coordination. The proposed adaptive method can also maintain the coordination of different protection zones of primary and backup relay pairs. In addition to analytical verification, the numerical results obtained from simulation show the efficiency of the proposed method. The proposed method is implemented on a power system with transmission lines and wind farms and simulated in MATLAB/Simulink environment.
Power systems
Ali Sefidgar-dezfouli; Mahmood Joorabian; Elaheh Mashhour
Abstract
This paper deals with the optimal scheduling of a microgrid (MG) equipped with dispatchable distributed generators (DGs), renewable generators and electrical storages (batteries). A chance-constrained model is developed to handle normal operation and emergency conditions of MG including DG outage and ...
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This paper deals with the optimal scheduling of a microgrid (MG) equipped with dispatchable distributed generators (DGs), renewable generators and electrical storages (batteries). A chance-constrained model is developed to handle normal operation and emergency conditions of MG including DG outage and unwanted islanding. Purchasing reserve from the upstream grid is also considered. Moreover, the uncertainties of loads and renewable resources are incorporated into the model. Furthermore, a novel probabilistic formulation is presented to determine the amount of required reserve in different conditions of MG by introducing separate probability distribution functions (PDFs) for each condition. Accordingly, an index named as the probability of reserve sufficiency (PRS) is introduced. The presented model keeps a given value of PRS in normal and emergency conditions of MG operation. In addition, some controllable variables are added to the chance constraints as an innovative technique to reduce the complexity of the model. Finally, a test microgrid is studied in different case studies and the results are evaluated.