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A surge of needs for the low carbon society promotes a spread of electric vehicle (EV). EVs could be charged at night simultaneously, as a result, severe voltage drop may happen. The authors have proposed the method which can compensate the voltage drop caused by EV charging by means of adjusting charging schedules and controlling reactive power. However, though the method can avoid the voltage violation,...
A new method to design a Voltage Source Inverter (VSI) for power factor correction with three phase induction machine as load is proposed. The machine parameters are obtained from practical induction machine. These parameters are employed for the simulation of induction machine. The control strategy presented in this paper is based on instantaneous reactive power theory. Simulation is carried out...
It was recently observed that a significant gap exists between the costs of Transmission Network Expansion Planning (TNEP) solutions produced by the DC power flow approximation and AC power flow heuristics. This paper confirms the existence of that gap and shows that DC-based TNEP solutions exhibit significant constraint violations when converted into AC power flows. The paper then demonstrates how...
The problem of controlling half bridge single phase unity power factor rectifier circuit is considered. The control objectives are to achieve i) output regulation and ii) near unity power factor in the presence of an uncertain load. The considered problem is dealt with using a double-loop controller developed on the basis of the system nonlinear model. The inner-loop is designed using Lyapunov technique...
The aim of this project is to develop a dynamic model of distribution network cell (DNC) using artificial intelligence approach. The increasing number of distributed generation (DG) technology has lead to difficulty in modeling the DNC model. The simple load modeling is no longer reliable in presenting the DNC model. In this project, the equivalent dynamic model of DNC consists of the converter-connected...
As solar energy continues to increase in the current power grid, the reactive power support capability from photovoltaic grid-tie inverters may be used to regulate feeder voltage and reduce system losses on medium- and low-voltage distribution systems. The focus of this paper is to develop a smart-grid-enabled control algorithm that will determine the amount of reactive power injection or absorption...
This paper presents a new development for load flow analysis in radial distribution systems. The aim of this paper is to reduce data preparation to solve load flow in distribution system. The proposed method uses simple equations and requires less computation time and number of iterations. The load flow algorithm used in this paper is based on forward and backward sweep method. The method is efficient...
This paper proposes an algorithm to calculate the optimal size and to locate the corresponding optimum place for minimizing power loss of the power system with considering load models for each bus. The method is tested on 30 bus test system. The results is analyzed and compared with that of comprehensive load flows and an approximate loss formula based method. Results show that the proposed approach...
This paper presents a simple and effective method for the voltage control of a three phase self excited induction generator (SEIG). The paper is divided into two sections; first section deals with modeling of self compensated SEIG. In the second section a detailed performance analysis of SEIG without and with compensation is carried out. Each of the two models is subjected to different operating conditions...
Power flow solutions are the key in many power system studies. In this paper, the power flow problem is formulated within rectangular coordinates. Using a voltage-dependent load model and linear approximation techniques, the problem is formulated as a system of mixed linear and nonlinear equations. An efficient matrix decomposition is then applied to facilitate establishing the Jacobian matrix in...
An increasing adoption of rooftop photovoltaic (PV) generators presents a growing opportunity for the use of their grid-tie inverters to provide reactive power compensation on medium- and low-voltage distribution networks. This paper presents a generalized method based on particle swarm optimization (PSO) for determining how much reactive power is necessary to provide control over the voltage profile...
Voltage stability buffers are necessary to prevent the power system from operating near the voltage collapse point. Operating the system close to its collapse point can result in voltage instability due to system model inaccuracies. Current methods for determining voltage stability buffers are based on arbitrary safety margins of typically 5%. In this paper, a new method has been developed to provide...
Cascading outages involve a series of dynamic phenomena that could lead to large blackouts and cause severe socio-economic loss. To better study these power system dynamic sequences when facing disturbance, a dynamic load model that mimics well the real behavior of the physical load is extremely important. Inappropriate load modeling could generate an inaccurate dynamic response in simulations and...
A modified load flow algorithm for microgrids operating in islanded mode is developed in this paper. The proposed algorithm is able to perform load flow calculations in networks without making use of the slack bus concept, and is suitable for applications to islanded microgrids. The developed algorithm includes the explicit representation of the steady-state characteristics of microsource controllers,...
In this paper, an approach based on the concept of Model Predictive Control (MPC) is used to control transmission voltages and prevent long-term voltage instability. The MPC model is based on a linearized steady-state system model derived from power flow equations. Simulation results are presented for the case of Nordic32 test system.
This paper presents a novel m ethod for evaluating Power flow in a radial distribution networks. Conventionally power flow algorithms used consider real and reactive power to be independent of node voltage which is not always true in case of distribution systems. Voltage sensitive nature of load imparts a considerable amount of influence over actual amount of power flowing in the system. A forward...
This paper describes an algorithm used for the load flow analysis of distribution system with distributed generation (DG). A simple model is proposed to carry out the load flow analysis of the radial distribution system including the distributed generation connected to the buses modeled as PV(constant active power and voltage magnitude) buses and negative PQ (constant active and reactive power) buses...
In recent years, the analysis of voltage stability has become crucial for the proper operation of electrical power systems, especially when it comes to large systems. The need for effective voltage control strategies have been brought to evidence in a considerable number of studies, as power system loads are located farther away from power plants and losses have tended to increase due to heavier power...
This paper presents a methodology to determine corrective adjustments in the demand when the power flow equations have no solution. This is formulated as a constrained optimization problem, which has the flexibility to select the buses that have load adjustment and those whose demand will be preserved. Useful information about the buses with major effects on the infeasibility of the power flow solutions...
By using simulation, compensating characteristics of a voltage sag compensator utilizing single-phase matrix converter is examined. System configuration is described and mathematical model of single-phase matrix converter is derived by using the state space averaging method. In addition, the single-phase matrix converter is stabilized by phase-lead compensation. Finally, compensating characteristics...
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