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Wind farms typically contain a variety of voltage control equipment including tap-changing transformers, switched capacitors, SVCs, STATCOMs, and the generators themselves. This paper focuses on the control of this equipment by addressing three major issues. The first is the ability of wind turbines to provide reactive power; voltage saturation in the collector system often limits the reactive power...
The fuzzy control theory is applied on reactive voltage control. With voltage and reactive power deviation as its input, and the transformer tap and capacitor switching as its output, MATLAB Fuzzy Logic Toolbox are used to form the fuzzy inference system. NanYi substation in JiangXi is an example. In the TH2100 software simulation, the results show that the control system is stable and reliable, the...
This paper presents and compares the performance of two controllers namely Fuzzy Logic and Proportional Integral applied to a voltage source inverter/converter operating as an active power filter. The active power filter is operated to compensate harmonics and reactive power generated by the non-linear load and power factor correction simultaneously. This work is performed in order to make an accurate...
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...
Wind energy is considered the most viable proposition among the renewable energy options. Of various Wind Energy Conversion Systems (WECS), fixed speed induction generator based WECS directly connected to the grid is the cheapest and simplest option and has the largest market share. This type of WECS does not require any power electronic interface to allow the grid connection unlike the variable speed...
An improved three-phase single-stage isolated power factor correction (PFC) converter topology is studied in this paper. The converter is based on full-bridge structure and operates in constant-frequency discontinuous conduction mode (DCM). Through the analysis on the working principle and mechanism of voltage spike of the original topology, a voltage-clamping circuit is proposed and added in primary...
For the sake of energy saving, harmonic current suppression and drive performance improvement, inverter-fed air-conditioner drive systems are used more and more extensively, and the selected motors include ASM,BLDCM and PMSM. Generally, the front stage AC/DC converter of inverter aircon is complete active power factor corrector (PFC), which can bring about better correction effects. Whereas the traditional...
A novel direct power control (DPC) strategy for three-level neutral-point-clamped (NPC) pulse-width-modulation (PWM) rectifier, based on fixed synthesizing vectors, is proposed in this paper. The strategy breaks through the restrictions of vector switching with a simple switching table, improves the excellent dynamic performance of DPC, avoids the neutral-point voltage unbalance and the excessive...
To draw a sinusoidal line current and to achieve high power factor and low voltage stress of power switches, Some single-phase three-level switching mode unidirectional rectifiers with power diodes have been presented. But there is an inherited disadvantage of imbalance of the DC-link voltage, which is difficult to be solved only by control method. A novel three-level rectifier with asymmetrical legs...
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...
A method of the thyristor rapid switched capacitors is presented in this paper, which breaks through the bondage of the conventional methods. In addition, a novel algorithm of two time reactive power has been presented, with which reactive power can be calculated fast. Meanwhile, with microcomputer synchronous phase lock technology, quick switching without transition can be realized, dynamic reactive...
A novel control method is presented for improving the reliability of transformerless cascade STATCOMs operating under various faults. A modified H bridge circuit is proposed, and it could be totally bypassed under various faults while the STATCOM keep working. During the fault transient, by controlling the phase of a STATCOMpsilas output voltage, the DC capacitors could be charged or discharged to...
This paper first investigates a local voltage and reactive power control (local control) in a distribution system based on local control of on-load tap-changer (OLTC), substation capacitors, and feeder capacitors, and how the presence of induction machine based distributed generation (DG) affects it. A proper coordination among those available voltage and reactive power control equipment to minimize...
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