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The increased power demand has led to lengthier, complex interconnections of power systems. Erection of new transmission lines is avoided due to environmental and economic reasons, hence increased power transfer in the existing system. To monitor and control of power system, continuous performance analysis is required; also FACTS devices helps in improving system performance. In this work, various...
Voltage Stability Analysis is a scheme to determine voltage stability margins and critical contingencies for various power transfers by identifying the weak regions of reactive power deficiency within these regions. Active power-voltage (PV) curve and reactive power-voltage (QV) are some of the well known tools for monitoring the voltage stability. To maintain voltage levels stability of the interconnected...
Problem statement for a renewable power system test site located at Nazarbayev University is formulated with consideration of a presence of uncertain disturbances from consumer grid side. Proposed controller is based on the method of additional equilibria. For adjusting of parameters of controller and control plant the genetic algorithm is proposed. Results of MATLAB simulation of designed control...
This research intends to create an environment in which the voltage stability can be analyzed by plotting P-V curve. In the advancement and development in the power system analysis, a tool on Matlab/Simulink has been developed. It can look how stable the system can operate based on the voltage surface when the load increases at any node. By repeating the power flow calculations with Newton- Raphson...
STATCOM with active power (energy) source provides an effective impact on transmission system. Although both the traditional STATCOM output voltage magnitude and phase angle can be controlled, they cannot be independently adjusted in steady state since the STATCOM has no significant active power capability. In this paper a study is carried out to compare the performance of STATCOM and Battery Energy...
This paper presents a Matlab/simulink model of grid-connected photovoltaic (PV) system, including a PV array, a control system, a distribution network and a load. Based on the accurate modeling system, optimum control and stability analysis are studied. The current control strategy can regulate the current at the point of common coupling to achieve the power factor control. The voltage control strategy...
This paper presents control methodology of UPFC (unified power flow controller) for stable operation of distributed generators on distribution system. The UPFC consists of two parts, shunt and series compensation parts. The shunt part controls the power flow from the power system to be constant. The series part compensates unbalanced voltage and voltage sag. In addition, the proposed UPFC keeps operation...
Distributed generation draws increasing attention because of the energy shortage and environmental protection considerations. Furthermore, distribution power generation can improve the power system stability and reliability, providing the local power supply economically. Microturbine based power generation has many applications in distributed generation. In this paper, a mathematical model of a microturbine...
The number of power inverter installations feeding renewable energy to AC grids is worldwide increasing. The type of inverter used depends on the power level and on the AC system conditions at the terminal connection point. Line-commutated inverters need sufficient short circuit power. Self-commutated inverters can even operate without an existing grid. In both the cases the mechanical inertia decreases...
In this study, the voltage stability of the bus load in various static and dynamic load systems that are fed by a wind farm has been examined. In the control of load voltage and reactive power, 10 MVAr static synchronous compensator (STATCOM) and static VAr compensator (SVC) is used. In the wind farm examined, Double Feed Induction Generator (DFIG) is used. In voltage and reactive power control, the...
The research work deals with the optimum placement of the compensating device (FACTS device) to improve the performance of existing transmission lines. The transmission line parameters have been obtained and analysis has been done on that parameters. The results reveal that: Power transfer capability and voltage profile of transmission line is improved with compensating device. Also the effect of...
In this study, two robust nonlinear control strategies are investigated to control the HVDC Lighttrade transmission systems. The controllerpsilas design are based on the sliding mode control (SMC) and Lyapunovpsilas control methodologies to deal with the nonlinearities introduced by requirements to power flow and line voltage. First, the steady state mathematical model of the HVDC Light system is...
The effects of constant power loads (CPLs) has been for long time the focus of research in isolated power systems such as automotive systems, electric ships and spacecrafts, with main focus on DC-systems. Due to the instability effect of the negative incremental resistance phenomena of CPLs, several criteria have been investigated to ensure system stability in the presence of large amount of CPLs...
This paper presents a new voltage control strategy for an electronically-interfaced distribution generation (DG) unit that utilizes a voltage-sourced converter (VSC) as the interface medium. The control strategy is based on the concept of voltage-controlled VSC (VC-VSC) rather than the conventional current-controlled VSC (CC-VSC). The proposed VC-VSC 1. enables operation of a DG unit in both grid-connected...
In this paper, the effect of the thyristor switched reactor-based static VAr compensator (SVC), which is one of flexible AC transmission systems (FACTS) controllers, to load voltages has been proposed in the three-phase system at static load and dynamic load conditions. The design and testing of TS R-based SVC are verified using the MATLAB/Simulink 7.04reg and Power Systems Toolbox. The results show...
Distributed generation (DG) is often used to export power to the utility system. Loss of main supply can cause a severe loading mismatch between DG generation and load consumption. Consequently, the voltage and frequency of the islanded system will cross the allowable limit. Due to this fact, it is essential to control the voltage and frequency in the islanding mode of operation. In this paper, control...
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