The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Loss allocation to each user based on fair and justice is the main content of electrical power transmission cost reasonable allocation in Electricity Market. Making use of the uniqueness of Shapley value and distinctive features of shapley theorem, power sources and load are regard as players in a union. That is transform power source to equivalent voltage source and load to impedance based on Thevenin...
This paper proposes a combined Secondary and Tertiary Voltage Regulation (SVR+TVR) methodology based on real-time optimal power flows (OPFs) to periodically update the generators' voltage regulator set points. Minimum active power losses (MAPL) and maximum loadability (ML) OPF approaches are used for the proposed SVR+TVR control. The presented technique is compared against a “classical” SVR control,...
This paper deals with an application of the power balance theory in a voltage and frequency controller (VFC) of an autonomous wind power generation using an isolated asynchronous generator (IAG) feeding three-phase four wire loads. The reference generator currents are estimated using the power balance theory to control the voltage and frequency of IAG system. Three-leg voltage source converter (VSC)...
In a deregulated electricity market one of the most important tasks of independent system operator (ISO) is to manage congestion as it threatens system security and may cause rise in electricity price resulting in market inefficiency. In corrective action of congestion management schemes, it is crucial for ISO to select the most sensitive generators to re-schedule their real and reactive powers optimally...
This article used VAR model to analyze and verify the symbiosis between Chinese coal mining machinery enterprises and coal mining enterprises from the perspective of static state and dynamic state, it concluded that: there is a co-integration relationship between the actual output value of Chinese coal mining machinery enterprises and the actual value of Chinese coal mining enterprises, namely, there...
Direct-drive wind power system needs a full-scale power converter to transmit the variable frequency electrical power to the grid. In order to improve the low voltage ride through (LVRT) capability, the grid-connected inverter (GCI) should work at a unity, a leading or a lagging power factor. Traditional control methods are complicated and output waveform is distorted by dead time. This paper introduces...
The control strategy for three-phase-high-power-factor PWM rectifier is studied, and the methodology of building the small signal model of the main power circuit is proposed in this paper. High frequency model for the rectifier mentioned and the input-to-output transfer function for the system are deduced with analysis. Design principle and method of the voltage regulator are given based on the model...
Variable speed wind turbines yield more energy than the fixed speed wind turbines, reduce power fluctuations and improve reactive power supply. The power quality of permanent magnet wind turbine with a direct-drive generator (PMWT) has been analyzed in this paper. A simulation model of variable speed wind turbine was developed with the simulation tool of PSCAD/EMTDC. Component models and equations...
This paper introduces a new vector control strategy of three-phase PWM rectifier. Because input currents of PWM rectifier are cross coupling in d-q coordinates, hysteresis regulators are used to achieve approximate decoupling control. Absolute error of d-q currents is considered while building d-q switching functions. Suitable space voltage vector is selected base on a switching function table. To...
This paper investigates feasible topologies of VSC-HVDC system for interconnecting large-scale off-shore wind farms. The corresponding control strategy is developed for coordination and control of the corresponding VSC-HVDC systems. A case of 5-terminal VSC-HVDC system is developed in MATLAB/ SIMULINK to demonstrate the validity of the proposed scheme. The proposed scheme may enable optimal integration...
The PI parameter setting of double closed-loop vector control of voltage source PWM rectifier is very important and largely depending on experience with few references available. In this paper, the influence of the PI parameters on the output dc voltage waveform of the rectifier is studied by simulation in Matlab/Simulink, based on which a simple and step-by-step method for the PI parameter setting...
Based on the principle and the launch profile of high speed long primary double-sided linear induction motor (DSLIM), the simulation model of the motor is constructed by using the moverpsilas field oriented control (FOC) method. The dynamic performance of the motor are simulated, and the rules of voltage, current, ratio of voltage to frequency, power factor, power efficiency and energy efficiency...
A dynamic model of back-to-back voltage source converter under synchronous rotating d-q coordinate system is developed. The system is transformed to a new equivalent nonlinear system which consists of a linear decoupled subsystem and a nonlinear subsystem characterizing the dynamics of the DC-link voltage in terms of the state variables in the linear subsystem via the feedback linearization technique...
The opposite-rotation dual mechanical ports (ODMP) PMSM is a novel machine applied to special situation, its electrical-magnetic relationship is different from traditional PMSM, so research on analysis method and design theory is necessary, especially for influence of main parameters on machine performance. The structure and operation principle are discussed. Its mathematic model adopted by dual d-q...
Based on feedback of the stator current phase, a new control strategy of doubly-fed induction generator (DFIG) is proposed. Under the condition that stator current amplitude maintains at rated value, the required rotor control voltage is directly calculated by the stator flux, rotor rotating speed, stator current phase and its corresponding error. Constant converter switching frequency and stator...
Taking Matlab/Simulink as a platform, a single-machine infinite-bus system simulation model of AC excited generator (ACEG) is established. The stator flux oriented vector control strategy and direct power control strategy of ACEG are proposed in this paper. With this model of ACEG, the steady state regulation characteristics of active power and reactive power and the transient processes of a sudden...
This paper presents a modified direct power control (DPC) strategy for a doubly fed induction generator (DFIG) based wind power generation system under unbalanced grid-voltage conditions. The strategy is based on the investigation of the mathematic model and the composition of the instantaneous active and reactive power outputted by DFIG. It is found that, by applying a notch filter of two times of...
On the base of studying on existing wind farm models in power flow calculation, two improved power flow algorithms for power system including wind farm which may be composed of squirrel cage induction generators (SCIG) or doubly-fed induction generators (DFIG) are presented in this paper. Since reactive power of wind farm is rectified synchronously in every power flow iterative process, the improved...
This paper describes the theory, the modeling technique, control scheme of unified power flow controller. Based on park transformation, it designs decoupled control scheme of UPFC shunt branch and cross-coupling control scheme of UPFC series branch in d and q-axis which eliminates the dynamic interaction between active and reactive power flow through the line. The control system of UPFC series branch...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.