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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 addresses the problem of coordinating voltage control in a large-scale power system partitioned into control areas operated by independent utilities. Two types of coordination modes are considered to obtain settings for tap changers, generator voltages, and reactive power injections from compensation devices. First, it is supposed that a supervisor entity, with full knowledge and control...
Dish-Stirling systems are a form of concentrating solar power (CSP) emerging as an efficient and reliable source of renewable energy. Various technical hurdles are involved in the grid interconnection of dish-Stirling systems, particularly with issues related to power factor correction, low voltage ride-through capability, and reactive power planning. While there are no grid-interconnection requirements...
This paper explores the performance of alternative voltage control strategy applied to direct drive synchronous wind generators, more specifically with permanent magnetic (PMSG). The reactive power control of the grid-side converter is investigated for voltage control purposes. In Brazil, the Grid National Operator (ONS) requires that wind turbines stay connected to the grid during voltage dips, but...
The paper investigates the possibility of ranking synchronous generators in a power system according to their contribution to system angular and voltage stability. The aim of this research is to establish fast semi-analytical methodology, i.e., avoiding transient simulations, to determine which synchronous generators can be safely disconnected from the network or replaced by other types of generators,...
This paper presents a comparative analysis about the influences of three inverter-based distributed generators control modes on several important aspects of distribution networks. The control modes investigated are constant current, constant reactive and active power, and constant voltage and active power. The investigated aspects are steady-state voltage profile, network losses, short-circuit currents...
This paper investigates the use of multi-linear regression models (MLRMs) and machine learning techniques for online voltage stability margin prediction. The methodology relies upon the relationship between system wide reactive power reserves and voltage stability margin. A comprehensive voltage stability assessment considering an extensive contingency list and several load increase directions is...
Due to growing competition in the electricity market, the drive for efficient, stable and secure grid operation makes voltage control in the transmission grid relevant. A solution that has potential is to increase the effectiveness of the ancillary service by automatic fast control. The paper describes a Wide Area Voltage Regulation (V-WAR) that fits this framework. The V-WAR is based on Secondary...
This paper introduces a differential evolution particle swarm optimization (DEPSO) method for dealing with optimal reactive power dispatch aiming at power loss reduction and voltage stability improvement. The optimum reactive power dispatch of power systems is to allocate reactive power control variables so that the objective function composed of power losses is minimized and the prescribed voltage...
In this paper, a new particle swarm optimization (PSO) algorithm namely Turbulent Crazy Particle swarm Optimization (TRPSO) is introduced to solve multi-constrained optimal reactive power dispatch in power system. Optimal reactive power dispatch problem is a multi-objective optimization problem that minimizes bus voltage deviations and transmission loss. The feasibility of the proposed algorithm is...
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)...
Renewable energy sources are becoming more and more important for power systems. With increasing sizes and a mandate to operate as financial entities seeking to maximize benefits in an electricity market, power systems require highly effective planning tools. In this paper, an optimal capacitor planning method based on optimal power flow is proposed for a power system with wind generators and PV arrays...
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...
The free piston energy converter (FPEC) is a new type of power unit for hybrid electric vehicle. In a FPEC, an internal combustion engine driven permanent magnet linear generator (PMLG) may be utilized to produce electrical energy. A three-phase active rectifier topology together with its controller is presented for controlling the generator output. The PMLG loaded with an active rectifier is modeled...
With the purpose of improving the operation efficiency of wind power generator, this paper, by analyzing the doubly-fed induction generatorpsilas (DFIG) power characteristic, built up the DFIG active power reference calculation model to achieve the maximal power point tracing (MPPT) and the reactive power reference calculation model to minimize generator loss. The stator flux-linkage oriented vector...
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 discusses a control strategy of direct-drive permanent magnet wind power system, and proposes back-to-back PWM converter control method that PWM technology is employed both in generator-side and grid-side. The system consists of permanent magnet synchronous generator (PMSG), PWM rectifier in generator-side, intermediate DC circuit, and PWM inverter in grid-side. DC voltage control is used...
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...
Generating electrical power from wind energy is becoming increasingly important throughout the world. This fast development has attracted many researchers and electrical engineers to work on this field. Self excited squirrel cage induction generator (SEIG), which uses an excitation capacitor, is used widely to convert mechanical wind energy to electricity, due to their low cost, small size, no need...
Compared with the doubly-fed AC excited wind-power generation system, the directly-driven permanent magnet synchronous generator (PMSG) for wind-power system has advantage of simpler structure, higher generation efficiency and more reliable operation. To solve the weakness associated with the traditional id=0 control scheme, such as relatively large power rating for generator-side converter and correspondingly...
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