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As the distributed generators are connected together through inverter interface in the microgrid, the control of the control of the interface inverter has an important influence on the operating performance of microgrid. In the paper, the study focuses on the control of the interfaced inverter, when microgrid operates in the islanded mode. In order to make the microgrid property similar to the utility...
The authors define the power components under sinusoidal and unbalanced conditions in three-phase, 4-wires circuits proposed as: dissymmetry power S-, and asymmetry power S0 as components of total unbalanced power Sunbalanced due to negative and zero currents components. The physical meaning of the power losses in unbalanced regimes is based on the losses on the neutral wire and on the increased losses...
The aim of optimal power flow is to discover an operating point that minimizes the generation cost while satisfying multiple operating constraints. Over the years, several techniques have been introduced to solve this non-linear optimization problem. In this paper, genetic algorithm deploying optimum non-uniform mutation rate and elitism has been used to solve this problem. After implementation of...
In this paper, a new method for controlling power factor in permanent magnet synchronous motor has been proposed in order to improve efficiency and decrease losses. In order to reach a in-time control for power factor, we have focused on parameters like current angle, torque angle, stator voltage and current in d axis stator. To this end, current angle, torque angle and stator voltage are considered...
The problem of multi-cell multi-user uplink sum-power minimization with required quality of service (QoS) under imperfect Channel State Information (CSI) and Probabilistic Contraints (PrCons) is solved. This paper is an extension of our previous work on statistical-CSI and PrCons. Deterministic constraints at times are infeasible or too expensive to implement, further, the CSI could be imperfect due...
Processes requiring a variable applied voltage often use power electronic devices. This causes reduced power factor and higher levels of current harmonic injection. Although power quality issues are typically rendered after the fact, by careful consideration during the design phase, equipment and/or processes can often be designed to achieve a better performance. This paper deals with methods for...
An approach based on a receding-horizon control scheme is here proposed for the optimal control of active and reactive power flows in microgrids (an aggregation of distributed energy resources (DER) of small size (such as photovoltaics, wind generation, cogeneration units — CHP, concentrated solar power — CSP, mini-hydro, energy storage)). Microgrids represent today one of the most promising technology...
Reactive power is an essential part of the power compared with active power. It is used to establish and sustain the magnetic field present in electrical equipment possessive of coils, such as transformers and electric machines. The reactive power consumption in large distribution networks can result in a huge reactive power flow, rising line current and a sub-nominal voltage. To avoid these negative...
This paper presents a new approach to solve the optimal reactive power dispatch (ORPD) problem based on hybridizing Particle Swarm Optimization (PSO) and Tabu-Search (TS) meta-heuristics (PSO-TS). The ORPD problem is formulated as a nonlinear constrained single-objective optimization problem where the real power loss is to be minimized. The proposed approach is used to find the settings of the control...
This paper deals with the development of an adaptive control system applied to voltage regulation of a standalone distributed power generation system, fed by self-excited induction generator. The generation system considers a four wire three-phase grid, composed by three phases plus neutral conductor, fed by three-phase three wires induction generator. The neutral conductor is created from the neutral...
Overvoltage and overloading due to high utilization of PVs are the main power quality concerns for future distribution power systems. This paper proposes a distributed control coordination strategy to manage multiple PVs within a network to overcome these issues. PVs reactive power is used to deal with over-voltages and PVs active power curtailment are regulated to avoid overloading. The proposed...
The paper proposes a new control strategy of a grid connected variable speed wind turbine (WT), based on a cascaded doubly fed induction generator (CDFIG). The generating plant is carried to extract the maximum power relative to the predicted mean wind speed, thus eliminating the power fluctuations associated to high frequencies component. Moreover the system attempts to adjust the power factor of...
The basic principles of UPFC operation are discussed and the series inverter dynamics are explained. Two control strategies — the Cross-Coupling method and the Advanced Control method are discussed in detail and their bode plots are analyzed. The two control methods are implemented in PSCAD for the NYPA UPFC at Marcy substation. The performance of the two methods is observed for step changes in active...
The single-stage flyback power factor correction (PFC) converter is well applied in medium and low power occasion such as adapters or LED drivers. Usually, the flyback PFC converter is preferred to operating in boundary conduction mode (BCM) for achieving high power factor (PF) and high efficiency at the same time. However, the conventional BCM control scheme such as input voltage tracking control...
This paper presents a power control study of a Wind Energy Conversion System (WECS) based on a Doubly Fed Induction Generator (DFIG) connected to the electric power grid. Proportional-Integral (PI) and Sliding Mode (SM) controls are used to compare the system's performances in terms of reference tracking and robustness to disturbance rejection and with respect to the machine parameters variation....
This paper is focused on the analysis and design of a switching control strategy to correct power factor, to regulate output voltage of a single-phase active three-level rectifier (SPATR) and to guarantee low harmonic distortion using a type of hysteresis current-mode control. The switching criterion is designed analyzing the stability of the switched linear system, to avoid information loss from...
Power frequency transformer is necessary when doubly fed induction generator (DFIG) connects with high-voltage ac grid. However power frequency transformer possesses many undesirable properties such as bulky size, environmental concerns. Additionally, the wind farms need reactive power compensation, such as static synchronous compensator (STATCOM). In this paper, the DFIG converter system with integrated...
Cascaded H-Bridge (CHB) multilevel converters provide a number of attractive features for photovoltaic (PV) power systems. They have high quality output waveforms, high efficiency and the ability to incorporate multiple Maximum Power Point Tracking (MPPT) schemes. This paper investigates the ability of the CHB PV system to export maximum power for different configurations of PV arrays among the H-Bridges...
STATic synchronous COMpensator (STATCOM) can be integrated into electric transmission systems to provide reactive power compensation and grid voltage support for achieving high-efficient and reliable Flexible AC Transmission Systems (FACTS). An emerging solution for STATCOM with modular structure and multilevel voltage output, named as modular multilevel STATCOM (mmSTATCOM) shows its great advantages...
This paper analyzes the steady state performance of isolated 3-phase self excited induction generator (SEIG) feeding balanced static resistive load. The effects of load and capacitance on magnetizing reactance, frequency, terminal voltage, currents have been shown in this paper. The model equations, which are nonlinear in nature, have been developed using graph theory. These equations can be easily...
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