Harmonic Analyses of Power Grid in Large-Capacity Groups of AC-DC-AC Frequency Speed Drag System

2013 ◽  
Vol 448-453 ◽  
pp. 1988-1993
Author(s):  
Ji Zhong Wang ◽  
Chao Nan Tong ◽  
Rui Li
Keyword(s):  
Power Supply ◽  
Pulse Width Modulation ◽  
Reactive Power ◽  
Power Grid ◽  
Harmonic Distortion ◽  
Power Load ◽  
Grid Side ◽  
Lc Filter ◽  
Harmonic Analyses ◽  
The Impact

Based on the synchronous machine in AC-DC-AC Frequency speed drag System, a new power supply method of phase shifting combination is proposed by a detailed study of the impact in the power grid harmonics. With regard to the main Motor drive system of hot-rolling finishing mills, a large number of varying parameters quantitative analysis is made respectively for power load, LC filter, pulse-width modulation circuit and transformer, in which the grid side harmonic rate and waveform distortion rate is focused on. The simulation results show that the power supply method with reasonable parameters design of the drag system can be drastically reduce the grid side harmonic interference that the total harmonic distortion is suppressed within 4.0%. Results of this study provides an effective method for the design of the factory drag system, reactive power compensation system as well as fault diagnosis of electric drag system.

scholarly journals Developing a grid-connected DFIG strategy for the integration of wind power with harmonic current mitigation

2019 ◽  
Vol 9 (5) ◽  
pp. 3905
Author(s):  
Hacil Mahieddine ◽  
Laid Zarour ◽  
Louze Lamri ◽  
Nemmour Ahmed Lokmane
Keyword(s):  
Power Flow ◽  
Pulse Width Modulation ◽  
Reactive Power ◽  
Voltage Source ◽  
Switching Frequency ◽  
Non Linear Load ◽  
The Moment ◽  
Grid Side ◽  
Lc Filter ◽  
Bidirectional Power Flow

<p>The aim of this paper is to present a study of the efficiency of the electrical part of a wind generation system. Two back-to-back PWM voltage-fed inverters connected between the stator and the rotor are used to allow bidirectional power flow. The second inverter grid side, has a role of a power active filter, to eliminate the harmonic generated by the non linear load, in the same time gives an active and reactive power needed by the rotor of DFIG. The harmonics of switching frequency in the current stator, pose a major problem in the moment where commutations in the diode bridge, to solve this problem, we introduce a small-sized passive LC filter for the purpose of eliminating high-frequency shaft voltage and grid current from a DFIG driven by a voltage-source pulse width-modulation rotor inverter controlled with SVM. The control theory is discussed, and the controller implementation is described. Design criteria are also given. The results of simulation tests show excellent static and dynamic performances.</p>

scholarly journals Comprehensive Modeling and Control of Grid-Connected Hybrid Energy Sources Using MPPT Controller

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5142
Author(s):  
Shazly A. Mohamed ◽  
Mohamed A. Tolba ◽  
Ayman A. Eisa ◽  
Ali M. El-Rifaie
Keyword(s):  
Pulse Width Modulation ◽  
Reactive Power ◽  
Weather Conditions ◽  
Energy Sources ◽  
Wind System ◽  
Low Carbon ◽  
Pwm Inverter ◽  
Grid Side ◽  
And Control ◽  
The Impact

Nuclear and renewables energies are the two variants for low-carbon energy and the evolving grid suggests possible synergies between them. Nuclear energy introduces supple operations based on power demand, while renewables such as PV and wind hybrid systems depend on the presence and strength of sunlight or wind. For grid stability, there is need to improve their performance in order to overcome the impact of this disadvantage. The paper is a step in this direction as it addresses a detailed comprehensive dynamic modeling and an efficient control of grid-connected energy sources such as PV or wind system to increase system reliability and to ensure the power quality and safe operation of critical demands. The behavior of the suggested hybrid system is tested at different climate circumstances such as variation of sun radiation and wind speed. The PV is equipped with a boost converter and a three-phase pulse width modulation (PWM) inverter. The wind energy comprises a doubly fed generator (DFIG) based on a variable-speed wind turbine. The two controllers’ rotor-side and grid-side converters of DFIG have the ability to generate and observe reactive power, to keep constant speed of the rotor and control the DC-link voltage. The proposed scheme was investigated using MATLAB software. The maximum power point tracking (MPPT) was used for two systems, PV and wind, in varying weather conditions. The simulation results prove that the voltage at the point of common coupling was constant. Furthermore, the injected current of the grid side was in sinusoidal form and was synchronized with grid side voltage. In addition, the injected power-to-utility grid was around power delivered by the hybrid PV and wind system.

Predictive Direct Power Control (PDPC) of Grid-connected Dual-active Bridge Multilevel Inverter (DABMI)

2017 ◽  
Vol 8 (4) ◽  
pp. 1524 ◽  
Author(s):  
H.H. Goh ◽  
Azuwien Aida ◽  
S.S. Lee ◽  
S.Y. Sim ◽  
K.C. Goh
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Power Grid ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Energy Integration ◽  
Direct Power ◽  
Direct Power Control ◽  
Dual Active Bridge ◽  
Model Predictive Control Algorithm

This paper deals with controlling a grid-connected dual-active bridge multilevel inverter for renewable energy integration. The concept of direct power control is integrated with model predictive control algorithm, which is termed as predictive direct power control, to control the real and reactive power injected into the power grid. The proposed multilevel inverter allows more options of feasible voltage vectors for switching vector selections in order to generate multilevel outputs, and thereby obtaining high power quality in the power grid. By using the predictive direct power control, simulation results show that the proposed multilevel inverter produces lower power ripple and manage to achieve currents with low total harmonic distortion which are well within the IEEE standard. The modeling and simulation of the system are implemented and validated by MATLAB Simulink software.

scholarly journals A Preventive Strategy of Voltage Stability based on Characteristic Analysis

2019 ◽  
Vol 115 ◽  
pp. 01001
Author(s):  
Zhen Hu ◽  
Ding Wang ◽  
Yangwu Shen ◽  
Daojun Chen ◽  
Yongyan Liu
Keyword(s):  
Control Strategy ◽  
Power Supply ◽  
Prevention And Control ◽  
Voltage Stability ◽  
Power Grid ◽  
Preventive Strategy ◽  
Characteristic Analysis ◽  
Node Voltage ◽  
And Control ◽  
The Impact

The purpose of voltage stability prevention and control strategy is to minimize the impact of expected accidents on the whole power grid while ensuring safe power supply. In this paper, it is expected that the accident has a large impact on the system voltage and makes the voltage margin of each node low. in order to not only adjust the node voltage, but also reduce the disturbance impact, a voltage stability prevention and control strategy is proposed based on the characteristic analysis.

scholarly journals Traction Power Substation Load Analysis with Various Train Operating Styles and Substation Fault Modes

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2788
Author(s):  
Zhongbei Tian ◽  
Ning Zhao ◽  
Stuart Hillmansen ◽  
Shuai Su ◽  
Chenglin Wen
Keyword(s):  
Power Supply ◽  
Normal Operation ◽  
Supply Network ◽  
Power Network ◽  
Power Load ◽  
Power Substation ◽  
Railway Traction ◽  
Train Operation ◽  
The Impact ◽  
Traction Power

The simulation of railway systems plays a key role in designing the traction power supply network, managing the train operation, and making changes to timetables. Various simulation technologies have been developed to study the railway traction power network and train operation independently. However, the interactions between the load performance, train operation, and fault conditions are not fully understood. This paper proposes a mathematical modeling method to simulate the railway traction power network with a consideration of a multi-train operation, driving controls, under-voltage traction, and substation fault modes. The network voltage, power load demands, and energy consumption according to the existing operation are studied. The hotspots of the power supply network are identified based on an evaluation of the train operation and power demand. The impact of traction power substation (TPSS) outage and a short circuit on the power supply network have been simulated and analyzed. The simulation results have been analyzed and compared with those of a normal operation. A case study based on a practical metro line in Singapore is developed to illustrate the power network evaluation performance.

Impact of Connecting Reactor on Stable Operation of Chain SVG Device

2014 ◽  
Vol 644-650 ◽  
pp. 794-797
Author(s):  
Zheng Dao Liu ◽  
De Sheng Xi ◽  
Qiang Liu ◽  
Lei Shi ◽  
Shu Han Wang ◽  
...  
Keyword(s):  
Electrical Property ◽  
Design Principle ◽  
Reactive Power ◽  
Power Grid ◽  
Stable Operation ◽  
Grid System ◽  
Reactive Compensation ◽  
Actual Operation ◽  
Design Requirements ◽  
The Impact

Chain SVG device is connected to the power grid via the reactor which is also referred to as connection reactor. Compared with other reactors of reactive compensation devices, It’s not like the serial filtering reactor which simply provides a specific quantity of inductive reactive power, or parallel phase control reactor which provides continuously adjustable inductive reactive power. The connection reactor in SVG is related to the impact of SVG on the power grid, the impact of the power grid system on SVG, and in particular, the compensation capacity and effect of SVG. Therefore, during design, requirements of SVG and electrical property of the compensated system should both be considered. In this paper, the impact of the connection reactor on SVG stable operation is analyzed in detail. The design principle that when choosing the reactor parameters, the impact on power unit DC side voltage should be prioritized is proposed, and simulation verification is conducted by using of PSCAD software. A reasonable reactor is selected for a 10kV SVG based on the conclusion. The actual operation result verifies the rationality of design.

The Research of the New High Voltage Reactive Power Compensation Device Based on the Compound Switch

2014 ◽  
Vol 496-500 ◽  
pp. 1097-1100 ◽  
Author(s):  
Yin Sheng Wang ◽  
Xue Di Qiao
Keyword(s):  
Reactive Power ◽  
Power Grid ◽  
Reactive Power Compensation ◽  
Parallel Capacitor ◽  
Thyristor Switch ◽  
Compensation Device ◽  
Equipment Utilization ◽  
Contact Switch ◽  
Current Zero ◽  
The Impact

With the increase of power system load, the demand for reactive power is also increasing. In order to ensure the power quality and improve equipment utilization, transmission of reactive power in power grid can lead to network loss and the voltage of the electricity. Installing reactive power compensation device in power grid is the essential means to meet the demand of power grid reactive power [1].The parallel capacitor reactive power compensation device is equipped in the coal mine 3.3 kV system reactive power compensation [2]. Introducing the parallel capacitor reactive power compensation principle and related problems, analysis of the current commonly uses contactor, relay and thyristor switch device, chooses the contactor and breaks pipe parallel composite switch which can have contact and non-contact switch to solve their problems [3]. Using software EMTP simulation composite switch voltage zero input, the result is very good to restrain the impact flow; Compound switch off after current zero avoids the contactor breaking arc, the simulation thyristor compound switch and diode in parallel.

scholarly journals A comparison study between fuzzy PWM and SVM inverter in NSMC control of stator active and reactive power control of a DFIG based wind turbine systems

2019 ◽  
Vol 8 (1) ◽  
pp. 78
Author(s):  
Habib Benbouhenni
Keyword(s):  
Power Control ◽  
Wind Turbine ◽  
Pulse Width Modulation ◽  
Reactive Power ◽  
Sliding Mode ◽  
Harmonic Distortion ◽  
Active Power ◽  
Wind Turbine System ◽  
Doubly Fed ◽  
Vector Modulation

In this work, we present a comparative study between space vector modulation (SVM) and fuzzy pulse width modulation (FPWM) technique in neuro-sliding mode control (NSMC) of stator reactive and stator active power control of the doubly fed induction generator (DFIG) for wind turbine system (WTS). Two controls approach using NSMC-SVM and NSMC-FPWM control scheme are proposed and compared. The validity of the proposed control techniques is verified by simulation tests of a DFIG. The reactive power, rotor current and stator active power is determined and compared in the above strategies. The obtained results showed that the proposed NSMC with FPWM strategy has stator reactive and active power with low powers ripples and low rotor current harmonic distortion than SVM technique.

scholarly journals Performance Improvement of a Grid-Tied Neutral-Point-Clamped 3-φ Transformerless Inverter Using Model Predictive Control

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 856 ◽  
Author(s):  
Hani Albalawi ◽  
Sherif A. Zaid
Keyword(s):  
Model Predictive Control ◽  
Leakage Current ◽  
Predictive Control ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Neutral Point ◽  
Pv Systems ◽  
Pv Panel ◽  
Current Controller ◽  
Lc Filter

Grid-connected photovoltaic (PV) systems are now a common part of the modern power network. A recent development in the topology of these systems is the use of transformerless inverters. Although they are compact, cheap, and efficient, transformerless inverters suffer from chronic leakage current. Various researches have been directed toward evolving their performance and diminishing leakage current. This paper introduces the application of a model predictive control (MPC) algorithm to govern and improve the performance of a grid-tied neutral-point-clamped (NPC) 3-φ transformerless inverter powered by a PV panel. The transformerless inverter was linked to the grid via an inductor/capacitor (LC) filter. The filter elements, as well as the internal impedance of the grid, were considered in the system model. The discrete model of the proposed system was determined, and the algorithm of the MPC controller was established. Matlab’s simulations for the proposed system, controlled by the MPC and the ordinary proportional–integral (PI) current controller with sinusoidal pulse width modulation (SPWM), were carried out. The simulation results showed that the MPC controller had the best performance for earth leakage current, total harmonic distortion (THD), and the grid current spectrum. Also, the efficiency of the system using the MPC was improved compared to that using a PI current controller with SPW modulation.

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