scholarly journals Voltage Unbalance, Power Factor and Losses Optimization in Electrified Railways Using an Electronic Balancer

Electricity ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 554-572
Author(s):  
António P. Martins ◽  
Pedro Rodrigues ◽  
Mahmoud Hassan ◽  
Vítor A. Morais
Keyword(s):  
Low Power ◽  
Power Factor ◽  
Electric Energy ◽  
Field Measurements ◽  
Electric Grid ◽  
Voltage Unbalance ◽  
Three Phase ◽  
Railway System ◽  
Regenerative Energy ◽  
Electrified Railways

Unbalanced currents, low power factor and high losses contribute to increasing the bill infrastructure managers must pay to the TSO/DSO operator that supplies electric energy to the railway system. Additionally, if regenerative energy coming from braking regimes is not allowed to be injected into the grid or even is penalized when it occurs, then the optimization of those parameters must be pursued. One of the possible measures that can be taken to counteract those phenomena is the installation of electronic balancers in heavy loaded substations in order to optimize the interface to the three-phase electric grid. This paper shows the benefit of such use taking examples from real conditions and realistic simulations assumed equivalent to field measurements.

The Research on Main Circuit Parameters and its Control Law of TCR Single-Phase to Three-Phase Power Converter

2015 ◽  
Vol 740 ◽  
pp. 359-363
Author(s):  
Shi Long Chen ◽  
Lu Luo ◽  
Yan Wu Wang
Keyword(s):  
Power Factor ◽  
Single Phase ◽  
High Reliability ◽  
Power Converter ◽  
Control Law ◽  
Configuration Theory ◽  
Three Phase ◽  
Railway System ◽  
Electrified Railway ◽  
And Control

The TCR single-phase to three-phase power converter has been widely used in electrified railway system as its simple control raw and high reliability. The research on main circuit parameters and its control law is necessary to design suitable TCR single phase to three phase power converter. This paper analyses the main circuit of TCR single phase to three phase power converter, and acquires the parameters configuration theory of each element in main circuit and control law of converter when the power factor varies from 0.7 to 0.9.

scholarly journals Three Phase Enhanced Electrical Energy Metering System

2020 ◽  
Vol 16 ◽  
Keyword(s):  
Low Power ◽  
Power Factor ◽  
Reactive Power ◽  
Electrical Energy ◽  
Human Errors ◽  
Existing Problems ◽  
Control Units ◽  
Three Phase ◽  
Energy Metering ◽  
Core Losses

This paper presents a practical solution for two existing problems in traditional electrical energy measurements. The first problem is the manual electrical billing system; so far, some countries are still adopting a manual technique with a high percentage of human errors and much complains from the consumers’ side and a lot of work from the authorities’ side. The second problem is having a low power factor at most of the domestic loads and some main commercial ones. Low power factor causes more current to flow in the network leading to an overheating of transformers and cables, and an increase of the core losses of transformers; in addition, less power factor means more burned fuel and more environment pollution. In This study, an automated solution for both problems is introduced, where two control units are added to the already existing three phase energy meters. The first unit solves the problem of manual billing by automatically calculating the monthly bill and sending monthly SMS messages to the consumers as well as authorities. The second unit solves the problem of low power factor by injecting reactive power using capacitor bank at the end load points to maintain a power factor of 0.95 at all load cases. A penalty will be added to the monthly calculated bill once the above value is violated. A prototype was implemented proving the capability of introducing both solutions using existing meters with a reasonable added cost

scholarly journals Improved Control Strategy for Three-Phase Microgrid Management with Electric Vehicles Using Multi Objective Optimization Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1146
Author(s):  
Muhammad Shahab ◽  
Shaorong Wang ◽  
Abdul Khalique Junejo
Keyword(s):  
Low Power ◽  
Electric Vehicles ◽  
Power Factor ◽  
Control Strategy ◽  
Ancillary Services ◽  
Dynamic Programming Method ◽  
High Peak Power ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Three Phase

The usage of electric vehicles (EV) have been spreading worldwide, not only as an alternative to achieve a low-carbon future but also to provide ancillary services to improve the power system reliability. A common problem encountered in the existing alternating current (AC) grids is low power factor, which cause several power quality problems and has worsened with the growing application of distributed generation (DG). Therefore, considering the spread of EVs usage for ancillary services and the low power factor issue in current electrical grids, this paper proposes an improved control strategy for power factor correction of a three-phase microgrid management composed of a photovoltaic (PV) array, dynamic loads, and an EV parking lot. This control strategy aims to support power factor issues using the EV charging stations, allowing the full PV generation. Different operation modes are proposed to fulfill the microgrid and the EV users’ requirements, characterizing a Multi Objective Optimization (MOO) approach. In order to achieve these optimization requests, a dynamic programming method is used to charge the vehicle while adjusting the microgrid power factor. The proposed control algorithm is verified in different scenarios, and its results indicate a suitable performance for the microgrid even during conditions of overload and high peak power surplus in generation unit. The microgrid power factor remains above the desired reference during the entire analyzed period, in which the error is approximately 4.5 less than the system without vehicles, as well as obtains an energy price reduction.

scholarly journals Improve the Three-phase Unbalance Rate of Railway System Under 2% By Three Kinds of Special Transformer Wiring

2021 ◽  
Author(s):  
Chien-Hsu Chen ◽  
Chin E. Lin
Keyword(s):  
Service Life ◽  
Load Capacity ◽  
Railway Vehicle ◽  
Voltage Unbalance ◽  
The Past ◽  
Three Phase ◽  
Railway System ◽  
Ieee Standard ◽  
Model Derivation ◽  
The Cost

Because imbalanced power will cause the loss of the propulsion motor of the railway vehicle, and the increase in temperature will shorten the service life of the electric vehicle. Not only this, but also increase the cost of electricity and maintenance. In the past, the industry only focused on methods to improve power quality such as load capacity, relay setting, and harmonic resolution. Now, the consider of three-phase unbalance rate (TPUR) must be applied. I propose special transformers wiring (STW) to improve the three unbalance rates and provide different transformer wiring methods. According to the IEEE Committee, in the future, power companies will need to install balanced relay stations to improve three-phase unbalance rate. the internal regulations of Taipower must be less than 4.5% (voltage unbalance rate (NPSUR)of 2.5% and motor temperature rise of 12.5%). the derivation of the transformer "three-phase unbalance rate" model is the focus of the railway system. This research is based on the model derivation of different wiring methods to improve the hot problem caused by the three-phase imbalance and improve the service life of the train. And pointed out that Scott, Le-Blanc, Modified-Woodbridge three wiring methods can be applied to future railway system routes to improve the three-phase unbalance rate, in line with the IEEE standard of less than 2%.

scholarly journals Improve the Three-Phase Unbalance Rate of Railway System Under 2% By Three Kinds of Special Transformer Wiring

2021 ◽  
Author(s):  
Hsu Chien Chen ◽  
Shir Kuan Lin ◽  
Chin-E. Lin
Keyword(s):  
Service Life ◽  
Load Capacity ◽  
Railway Vehicle ◽  
Voltage Unbalance ◽  
The Past ◽  
Three Phase ◽  
Railway System ◽  
Ieee Standard ◽  
Model Derivation ◽  
The Cost

Because imbalanced power will cause the loss of the propulsion motor of the railway vehicle, and the increase in temperature will shorten the service life of the electric vehicle. Not only this, but also increase the cost of electricity and maintenance. In the past, the industry only focused on methods to improve power quality such as load capacity, relay setting, and harmonic resolution. Now, the consider of three-phase unbalance rate (TPUR) must be applied. I propose special transformers wiring (STW) to improve the three unbalance rates and provide different transformer wiring methods. According to the IEEE Committee, in the future, power companies will need to install balanced relay stations to improve three-phase unbalance rate. the internal regulations of Taipower must be less than 4.5% (voltage unbalance rate (NPSUR)of 2.5% and motor temperature rise of 12.5%). the derivation of the transformer "three-phase unbalance rate" model is the focus of the railway system. This research is based on the model derivation of different wiring methods to improve the hot problem caused by the three-phase imbalance and improve the service life of the train. And pointed out that Scott, Le-Blanc, Modified-Woodbridge three wiring methods can be applied to future railway system routes to improve the three-phase unbalance rate, in line with the IEEE standard of less than 2%.

scholarly journals Three-Phase Power Analyzer using Labview

2020 ◽  
Vol 9 (3) ◽  
pp. 1822-1825
Keyword(s):  
Power Systems ◽  
Low Power ◽  
Real Time ◽  
Power Quality ◽  
Power Factor ◽  
Power Distribution ◽  
Virtual Experiments ◽  
Three Phase ◽  
Electrical Devices ◽  
Linear And Nonlinear

An important requirement of power systems in this decade is the capability of power distribution among electrical devices and systems to improve power quality that depends on various factors, such as reactive, active, and apparent power. Virtual experiments and testing are considered important factors to achieve the best performance in this area. This research mainly aims to find low power factors and load to meet the requirements of electrical devices. Calculations are conducted on a real-time simulator LabVIEW to verify the effectiveness of linear and nonlinear values on the load to achieve the power factor.

A Intergrated Compensation Device Design for Three-Phase Unbalance and Reactive Power of Low Line

2013 ◽  
Vol 706-708 ◽  
pp. 601-608
Author(s):  
Hai Xiang Wang ◽  
Wei Peng Zhou ◽  
A Fang Hang
Keyword(s):  
Low Power ◽  
Power Factor ◽  
Reactive Power ◽  
Software Process ◽  
Frequency Detection ◽  
Thyristor Switch ◽  
Three Phase ◽  
Detection Circuit ◽  
Compensation Device ◽  
Switch Circuit

The harm of high three-phase unbalance factor and low power factor is introduced. The design of hardware and software process is given. The design of AD circuit , adjust circuit , frequency detection circuit and thyristor switch circuit is illustrated.

scholarly journals Considerations on Current and Voltage Unbalance of Nonlinear Loads in Residential and Educational Sectors

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 102
Author(s):  
Gabriel Nicolae Popa ◽  
Angela Iagăr ◽  
Corina Maria Diniș
Keyword(s):  
Power Factor ◽  
Single Phase ◽  
Low Voltage ◽  
Industrial Sector ◽  
Phase System ◽  
Nonlinear Loads ◽  
Voltage Unbalance ◽  
Large Numbers ◽  
Three Phase ◽  
Power Substation

Most often, electrical consumers in the residential and educational sectors are different from industrial electrical consumers. Whereas the vast majority of industrial electrical consumers are low-voltage, three-phase (with three or four wires), electrical consumers in the residential and educational sectors are low-voltage, single-phase. However, in practice, electrical consumers in the residential and educational sectors are in large numbers. Usually, current and voltage unbalances are lower in the industrial sector compared to the residential and educational sectors, where there are a large number of low-voltage, single-phase consumers that are connected/disconnected in an uncontrollable way and that need to be wired and balanced on each phase of power transformers from power substations. The purpose of this paper is to present the results of electrical balance and improve the power factor in the power substation from residential and educational sectors. The paper investigates the current and voltage unbalance of nonlinear con sumers in the residential and educational sectors. For this purpose, we performed measurements in the laboratory and the power substation to investigate the unbalance in the three-phase system. Laboratory measurements were made in the unbalanced operation of the single-phase electrical consumers connected at three-phase system. The measurements from power substation were carried out after the electrical consumers were uniformly spread among the three phases from the low-voltage power network, on two different days: a workday and a weekend day. The current and apparent power unbalance were reduced and the power factor was improved using the capacitive single-phase electric consumers (e.g., personal computers, which are in large numbers in such sectors) evenly across the phases.

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