scholarly journals Topologies and Operation Modes of Rail Power Conditioners in AC Traction Grids: Review and Comprehensive Comparison

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2151 ◽  
Author(s):  
Mohamed Tanta ◽  
José Gabriel Pinto ◽  
Vitor Monteiro ◽  
Antonio P. Martins ◽  
Adriano S. Carvalho ◽  
...  
Keyword(s):  
Power Quality ◽  
Single Phase ◽  
Power Grid ◽  
Power Transformers ◽  
Correct Selection ◽  
Operation Modes ◽  
Three Phase ◽  
Different Types ◽  
Traction Substations ◽  
Comprehensive Comparison

Electric locomotives in AC traction power systems represent a huge single-phase non-linear load and, detrimentally, affect the power quality and the efficiency of the three-phase power grid. Nevertheless, along the last decades, power electronics are being used to mitigate power quality problems in the three-phase power grid. In particular, Rail Power Conditioner (RPC) helps to increase the loading capacity of traction substations and improve the power quality of three-phase power grids. As the main characteristics, an RPC can supply reactive power, suppress current harmonics and overcome currents imbalance of the three-phase power grid. On the other hand, the traction substations may be constituted by different types of power transformers. For instance, single-phase power transformers and open-delta (V/V) power transformers are widely used, while Scott power transformers are less frequently used, since they are more complex and expensive. In this framework, this work presents a review study of RPC topologies, including their operation modes, and a comprehensive comparison between the characteristics of the RPC topologies when using different types of AC traction substations and power transformers. This helps to ensure the correct selection of the RPC topology for a specific application, according to the main structure of the traction substation. Consequently, and based on the established review, it is possible to sort and allocate each RPC topology for limited or wider applications.

scholarly journals Modeling of three-phase electric motor operation by the MATLAB system with deteriorated power quality in the 0.38 kV distribution networks

2018 ◽  
Vol 58 ◽  
pp. 03016 ◽  
Author(s):  
I.V Naumov ◽  
N.V. Savina ◽  
M.V. Shevchenko
Keyword(s):  
Induction Motor ◽  
Power Quality ◽  
Electric Motor ◽  
Distribution Networks ◽  
Negative Sequence ◽  
Operation Modes ◽  
Three Phase ◽  
Sequence Components ◽  
Motor Operation ◽  
The Impact

One of the main operation modes that characterizes power quality in distribution networks is asymmetry of three-phase voltage system. Operation of an induction motor (IM) with disturbed voltage symmetry in the supply network can not be considered as a rated one. The system of voltages applied to the stator winding of IM under these conditions contains positive- and negative-sequence components. This worsens the performance characteristics of IM essentially. In order to balance the 0.38 kV network operation and enhance the efficiency of the three-phase electric motor operation it is suggested to use a special balancing unit (BU) that minimizes the negative-sequence components of current and voltage. The operation modes of the obtained system “supply source – induction motor – balancing unit” are simulated within the MATLAB software package of applied programs, which allows one to assess the impact of low quality of power on the operating characteristics of the electric motor and the efficiency of the balancing unit to increase the “durability” of the motor under the asymmetrical power consumption.

10kV Grid Arc Grounding Over-Voltage Hazards and Countermeasures

2013 ◽  
Vol 392 ◽  
pp. 489-493
Author(s):  
Qing Hao Wang ◽  
Zi Jun Huang ◽  
Zhi Gang Li ◽  
Bo Fang ◽  
Gui Bin Hu
Keyword(s):  
Single Phase ◽  
Power Grid ◽  
Operation Mode ◽  
Scientific Basis ◽  
Neutral Point ◽  
Correct Selection ◽  
Capacitive Current ◽  
Current Test ◽  
Selection Of

Through the analysis of 2 single-phase grounding over voltage accidents caused by capacitive over current in 10 kV power grid in this paper, the causes and damages of arc grounding over voltage are illustrated, and the necessity of capacitive current test and effective methods are pointed out. The test and assessment to the 29 substations capacitor currents provides a scientific basis for the correct selection of the neutral point operation mode, and the strengths and weaknesses of the neutral Point grounding through the arc suppression circle and the mode trends of 10kV grid neutral grounding are demonstrated.

Research on Single-Phase Back-to-Back SVG Solution of Power Pollution of Traction Transformer to Accessed Grid

2014 ◽  
Vol 687-691 ◽  
pp. 3411-3414
Author(s):  
Jia Yong Chen ◽  
Kun Ya Guo ◽  
Peng Jin ◽  
Shu Han Wang
Keyword(s):  
Power Quality ◽  
Single Phase ◽  
High Harmonic ◽  
Electric Locomotive ◽  
The Public ◽  
Three Phase ◽  
Static Var Generator ◽  
Railway Traction ◽  
Electrified Railway

Electrified railway traction transformer is a pivot that connects the electric locomotive and the public grid. Therefore, power quality problems caused by electric locomotive such as three-phase voltage imbalance, great voltage fluctuation and high harmonic content can be transmitted to the public grid via the traction transformer. To solve this problem, the solution of two sets of single-phase SVG (Static Var Generator) in back-to-back operation to solve power quality problems of the electrified railway is raised. This solution has been proved by practice effective in improving power quality of the traction transformer.

scholarly journals Design and analysis of a Three Phase Transformerless Hybrid Series Active Power Filter based on sliding mode control using PQ-theory and stationary reference frames

2019 ◽  
Vol 16 (3) ◽  
pp. 289-310 ◽  
Author(s):  
Vinay Naguboina ◽  
Satish Gudey
Keyword(s):  
Power Quality ◽  
Single Phase ◽  
Sliding Mode ◽  
Active Power Filter ◽  
Constant Load ◽  
Active Power ◽  
Phase System ◽  
Load Voltage ◽  
Power Filter ◽  
Three Phase

In this work, a Three phase Transformerless Hybrid Series Active Power Filter (THSeAF) based on Sliding Mode Control (SMC) is proposed to mitigate the voltage and current distortions present in an electrical distribution systems (EDS). A Sliding Mode Controller is designed by controlling the parameters present on the load side as well as source side of the system. Three separate voltage source converters (VSC) are used. The mod1elling of the system is derived by considering a single-phase system by using state space analysis. The frequency response characteristics have been derived for the single-phase system and the stability of the system is studied. It is observed that the system has good stability margins when the SMC is applied at the source side compared to load side. Simulation results obtained in PSCAD/EMTDC v4.6 have been observed for power quality issues like voltage sags, voltage swells, voltage distortions, voltage unbalances and their concurrent occurrence. The approach of stationary reference frame was used for source side control and PQ theory is used for load side control. It is observed that the proposed controller works well in obtaining a stable and constant load voltage during these power quality issues. The difference in settling time observed is around 4 ms for the load side and source side control. The THD present in the load voltage is near about 1%. The SMC is found to be robust in obtaining a constant load voltage with low THD and an improved power factor.

Identification of Power Grid Lines with Increased Power Losses Using Mobile Electric Meters and Timers

2020 ◽  
pp. 31-36
Author(s):  
Aleksandr V. Vinogradov ◽  
Aleksey V. Bukreyev ◽  
Alina V. Vinogradova ◽  
Vadim E. Bol’shev
Keyword(s):  
Single Phase ◽  
Power Grid ◽  
Electricity Consumption ◽  
Electrical Energy ◽  
Research Purpose ◽  
Power Losses ◽  
Electric Networks ◽  
Operating Modes ◽  
Three Phase ◽  
Quality Of Electrical Energy

Identifying sections of 0.4 kilovolt power grid lines with increased power losses is an urgent task, the solution of which will free up some of the funds spent by power grid companies to compensate for power losses and direct them to the reconstruction and modernization of electric networks. It is necessary to monitor electricity consumption on sections of power grid lines and on the connections of consumers, and compare data on consumption. Existing devices that analyze the quality of electrical energy and can control current and power in the network, such as power quality analyzers, do not have the full necessary qualities, since they are intended for other purposes, and they are also very expensive. (Research purpose) The research purpose is in developing technical means for identifying sections of 0.4 kilovolt power grid lines with increased power losses, which also allow performing a survey of operating modes of power grid lines. (Materials and methods) The article presents a review of literary sources and an analysis of statistical data. (Results and discussion) The article presents developed technical tools for inspection of power grid lines of 0.4 kilovolts and identification of areas with increased losses of electrical energy, portable single-phase and three-phase electric meter and timer. The single-phase mobile electric meter and timer can be used for the survey of single-phase connections of consumers, three-phase one can be used for the survey of any sections of power lines. Authors also developed a version of the portable electric meter and timer with up to six independent sensors. (Conclusions) It is most rational to use a version of the mobile meter and timer equipped with Wi-Fi data transmission technology to detect power losses on sections of 0.4 kilovolts power grid lines, since in this case simultaneous monitoring of several sections is provided with the possibility of obtaining information from sensors in real time. The data allow to calculate technological and commercial losses on power line sections and draw conclusions about whether they are overstated.

scholarly journals Design of alternating current voltage–regulating circuit based on thyristor: Comparison of single phase and three phase

2020 ◽  
Vol 53 (5-6) ◽  
pp. 884-891
Author(s):  
Zonglu Zhang
Keyword(s):  
Normal Level ◽  
Single Phase ◽  
Simulation Analysis ◽  
Power Grid ◽  
Voltage Regulation ◽  
Voltage Sag ◽  
Voltage Regulator ◽  
Phase Voltage ◽  
Current Voltage ◽  
Three Phase

The voltage sag problem in a power grid can be solved by a voltage regulator. In this study, the voltage regulator based on thyristor was used to compensate the single-phase and three-phase voltage of voltage sag fault, so as to recover the normal level of voltage. The simulation analysis was carried out on MATLAB. The results showed that voltage sag faults mainly affected the amplitude of voltage, but not the frequency of voltage. After voltage regulation, the single-phase and three-phase voltage waveforms in the fault period had a certain recovery, but the voltage regulator had a certain hysteresis effect.

A Novel Hybrid Unified Power Quality Conditioner (UPQC) for Medium-Voltage Power Grid

2013 ◽  
Vol 816-817 ◽  
pp. 774-777
Author(s):  
Tian Bo Zhu ◽  
Hua Geng
Keyword(s):  
Power Quality ◽  
Simulation Study ◽  
Power Grid ◽  
Power Devices ◽  
Detailed Design ◽  
Matlab Simulink ◽  
Medium Voltage ◽  
Harmonic Currents ◽  
Three Phase ◽  
Power Quality Conditioner

This paper proposed a three-phase three wire UPQC (hybrid UPQC). The topology is novel which consists of a series and a hybrid shunt filters. The unique topology can reduce the capacity of power devices in the hybrid UPQC when compensating source harmonic currents. In this paper a detailed design about the main circuit is presented. Finally a simulation study of the proposed hybrid UPQC has been carried out by using MATLAB/Simulink. The results verified the effectiveness of the UPQC topology.

The Research of Unbalanced Three-Phase Adjustment in Distribution Network

2012 ◽  
Vol 263-266 ◽  
pp. 649-654
Author(s):  
Yan Wei Zheng ◽  
Zhong Hai Bai ◽  
Zhi Quan Feng
Keyword(s):  
Power Quality ◽  
Single Phase ◽  
Low Voltage ◽  
Distribution Network ◽  
Voltage Distribution ◽  
Phase Adjustment ◽  
Adjustment Strategy ◽  
Three Phase ◽  
Network Losses

To balance three-phase loads in distribution network with abundant of single-phase loads, the idea of three-phase adjustment and wiring method is proposed in this paper. Three-phase adjustment controller is designed, and the least load adjustment strategy is proposed, which can adjust the three-phase load to roughly balance automatically. The system can solve the serious three-phase unbalance problem of the lines with single-phase load, which may instead of capacitive compensation in low voltage distribution network. It can improve power quality and reduce network losses.

Error Calibration of Three-Phase Method for Combined Transformer

2014 ◽  
Vol 986-987 ◽  
pp. 1821-1825
Author(s):  
Bing Ai ◽  
Qiang Shi
Keyword(s):  
Single Phase ◽  
Power Grid ◽  
Electric Energy ◽  
Large Error ◽  
Phase Method ◽  
Experimental Platform ◽  
Three Phase ◽  
Energy Metering ◽  
Error Calibration

Three-phase combined transformer has a large number of application to special energy metering in power grid, its performance is directly related to the accuracy of electric energy metering. So it is necessary to ensure its performance and accuracy. It rules that three-phase combined transformer should be calibrated with three-phase method, but most of metrology departments calibrate three-phase combined transformer in single-phase method. Based on the mechanism of the three-phase transformer, single-phase method and three-phase method had been compared on three-phase transformer experimental platform. The result shows that it would be large error when the three-phase transformers are calibrated with single-phase method. Three-phase transformer calibration should be operated with three-phase method.

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