scholarly journals Multi-Point Time-Synchronized Waveform Recording for the Analysis of Wide-Area Harmonic Propagation

2020 ◽  
Vol 10 (11) ◽  
pp. 3869 ◽  
Author(s):  
Stanislav Babaev ◽  
Ravi Shankar Singh ◽  
Sjef Cobben ◽  
Vladimir Ćuk ◽  
Allan Downie
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Distribution Networks ◽  
Harmonic Load ◽  
Medium Voltage ◽  
Voltage Distortion ◽  
Pv Inverter ◽  
Distributed Measurement ◽  
Selection Of

This paper focuses on studying the phenomenon of harmonic distortion propagation through distribution networks. This phenomenon is governed by a combination of factors involving the nature of harmonic loads and their dynamic interaction, the influence of background voltage distortion, and harmonic impedance values. The objective of the proposed research includes evaluation of the network response at different nodes to harmonic current injections via utilizing a time-synchronized distributed measurement system. The study is performed in a fully controlled and flexible test network with three medium voltage/low voltage (MV/LV) distribution substations and several managed LV harmonic sources, namely PV inverter, single-phase EV charger and emulated harmonic load with reference current injections. A selection of the results is analyzed and interpretation of the observed phenomena is given with implications that synchronized harmonic measurements can be considered as potential powerful instruments for analyzing power quality disturbances.

scholarly journals Analisis Pengaruh Harmonisa terhadap Rugi-Rugi Daya pada Sistem Tegangan Rendah dan Transformator GR088 di Penyulang Menjangan

2018 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Salim Afif ◽  
I W. Sukerayasa ◽  
W. G. Ariastina
Keyword(s):  
Direct Measurement ◽  
Low Voltage ◽  
Flow Analysis ◽  
Harmonic Distortion ◽  
Load Flow ◽  
Network System ◽  
Harmonic Load ◽  
Medium Voltage ◽  
Load Flow Analysis ◽  
Harmonic Distortions

Menjangan feeder is a medium-voltage network system which distributes electricity throughout Gilimanuk and some areas in Buleleng. It has 69 distribution substations, which one of them, substation GR088, contributes to the highest value of the total harmonic distortion (THDi). In this research, the effect of harmonic distortions on losses at low voltage system of substation GR088 will be evaluated.The method used in this study is direct measurement of harmonic distortions at each low-voltage costumer whose electricity is generated by substation GR088 at Menjangan Feeder. Software is also used to perform harmonic load flow analysis and simulations. The total value of losses on transformer and low voltage system of substation GR088 Menjangan feeder, in a no-harmonic condition is 1481,7 Watt. On under-harmonic condition, the total value of losses is 1552,5 Watt. Therefore there is a 70,8 Watt difference between the two conditions. At this case, beside the heat created by the harmonic distortion that can affect the performance of transformers, it also cause a quite great value of losses, which is 1,7 kWh per day, or approximately 620 kWh per year. It means the harmonic distortion in substation GR088 can cause PT PLN (Persero) lose Rp.910.018,8 per year.

scholarly journals Software Solution for Modeling, Sizing, and Allocation of Active Power Filters in Distribution Networks

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 133
Author(s):  
Dawid Buła ◽  
Dariusz Grabowski ◽  
Michał Lewandowski ◽  
Marcin Maciążek ◽  
Anna Piwowar
Keyword(s):  
Power Systems ◽  
Modeling And Simulation ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Distribution Networks ◽  
Active Power ◽  
Active Power Filters ◽  
Power Filters ◽  
Depth Analysis ◽  
Selection Of

The paper is related to the problem of modeling and optimizing power systems supplying, among others, nonlinear loads. A software solution that allows the modeling and simulation of power systems in the frequency domain as well as the sizing and allocation of active power filters has been developed and presented. The basic assumptions for the software development followed by the models of power system components and the optimization assumptions have been described in the paper. On the basis of an example of a low-voltage network, an analysis of the selection of the number and allocation of active power filters was carried out in terms of minimizing losses and investment costs under the assumed conditions for voltage total harmonic distortion (THD) coefficients in the network nodes. The presented examples show that the appropriate software allows for an in-depth analysis of possible solutions and, furthermore, the selection of the optimal one for a specific case, depending on the adopted limitations, expected effects, and investment costs. In addition, a very high computational efficiency of the adopted approach to modeling and simulation has been demonstrated, despite the use of (i) element models for which parameters depend on the operating point (named iterative elements), (ii) active filter models taking into account real harmonics reduction efficiency and power losses, and (iii) a brute force algorithm for optimization.

scholarly journals Machine Learning and GIS Approach for Electrical Load Assessment to Increase Distribution Networks Resilience

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4133
Author(s):  
Alessandro Bosisio ◽  
Matteo Moncecchi ◽  
Andrea Morotti ◽  
Marco Merlo
Keyword(s):  
Machine Learning ◽  
Distribution System ◽  
Low Voltage ◽  
Regression Tree ◽  
Distribution Networks ◽  
Machine Learning Algorithms ◽  
Extreme Weather Events ◽  
Medium Voltage ◽  
Weather Events ◽  
Building Area

Currently, distribution system operators (DSOs) are asked to operate distribution grids, managing the rise of the distributed generators (DGs), the rise of the load correlated to heat pump and e-mobility, etc. Nevertheless, they are asked to minimize investments in new sensors and telecommunication links and, consequently, several nodes of the grid are still not monitored and tele-controlled. At the same time, DSOs are asked to improve the network’s resilience, looking for a reduction in the frequency and impact of power outages caused by extreme weather events. The paper presents a machine learning GIS-based approach to estimate a secondary substation’s load profiles, even in those cases where monitoring sensors are not deployed. For this purpose, a large amount of data from different sources has been collected and integrated to describe secondary substation load profiles adequately. Based on real measurements of some secondary substations (medium-voltage to low-voltage interface) given by Unareti, the DSO of Milan, and georeferenced data gathered from open-source databases, unknown secondary substations load profiles are estimated. Three types of machine learning algorithms, regression tree, boosting, and random forest, as well as geographic information system (GIS) information, such as secondary substation locations, building area, types of occupants, etc., are considered to find the most effective approach.

Single-Phase Generation Headroom in Low-Voltage Distribution Networks Under Reduced Circuit Characterization

2015 ◽  
Vol 30 (2) ◽  
pp. 1006-1011 ◽  
Author(s):  
Pedro M. S. Carvalho ◽  
Luis A. F. M. Ferreira ◽  
Joao J. E. Santana
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Distribution Networks ◽  
Voltage Distribution

scholarly journals Modeling Features of a Single Phase-to-Earth Fault in a Medium Voltage Overhead Transmission Line

2020 ◽  
Vol 4 (2) ◽  
pp. 127-138
Author(s):  
Ismael Saeed ◽  
Kamal Sheikhyounis
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Single Phase ◽  
Single Frequency ◽  
Mathematical Representation ◽  
Medium Voltage ◽  
Overhead Transmission Line ◽  
Earth Fault ◽  
Distributed Parameters ◽  
Selection Of

The modeling and calculation of a single phase-to-earth fault of 6 to 35 kV have specific features when compared with circuits with higher nominal voltages. In this paper, a mathematical analysis and modeling of a 3-phase overhead transmission line with distributed parameters consisting of several nominal T-shaped, 3-phase links with concentrated parameters replaced by 1 nominal T-shaped link were carried out. Further analysis showed that not accounting for the distributed nature of the line parameters did not cause significant errors in the assessment of the maximum overvoltage in the arc suppression in single phase-to-earth faults, and that sufficient accuracy insures the representation of the line by only 1 nominal T-shaped, 3-phase link. Such a modeling technique makes it impossible to identify the location of single-phase faults, which is the property of higher harmonic amplification of individual frequencies. Chain equivalent schemas with constant parameters are valid for a single frequency, thereby providing an opportunity to study the nature of the wave process by the discrete selection of parameters. Next in the mathematical representation, we consider the overhead transmission lines as lines with distributed parameters.

Implementation of Single-Phase Two-Switch Midpoint Unidirectional Multilevel Converter System

2018 ◽  
Vol 19 (4) ◽  
Author(s):  
Peethala Rajiv Roy ◽  
P. Parthiban ◽  
B. Chitti Babu
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Open Loop ◽  
Current Control ◽  
Control Technique ◽  
Control Scheme

Abstract This paper deals with implementation of a single-phase three level converter system under low voltage condition. The frequency of the switches is made constant and involves change in ${t_{on}}$ and ${t_{off}}$ duration. For this condition the pulse width modulation control scheme for a single phase three level rectifier is developed to improve the power quality. The hysteresis current control technique is adopted to bring forth three-level PWM on the dc side of the bridge rectifier and to achieve high power factor and low harmonic distortion. Based on the proposed control scheme, the line current is driven to follow the sinusoidal current command which is in phase with the supply voltage. By using three-level voltage pattern the blocking voltage of each power device is clamped to half of the dc link voltage. The simulation and experimental results of 20W converter under low input voltage condition are shown to verify the circuit performance. Open loop simulation and hardware tests are implemented by applying a low voltage of 15 V(rms) on the input side.

Synchronization of a Single-phase Photovoltaic Generator With the Low-Voltage Utility Grid

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Nader Anani ◽  
Omar Al-Kharji ◽  
Prasad Ponnapalli ◽  
Saleh Al-Araji ◽  
Mahmoud Al-Qutayri
Keyword(s):  
Renewable Energy ◽  
Single Phase ◽  
Low Voltage ◽  
Phase Lock Loop ◽  
Phase Detector ◽  
Small Scale ◽  
Correct Operation ◽  
Phase Lock ◽  
Pv Inverter ◽  
Single Phase Inverter

The increased generation of electrical energy from renewable sources and its integration into the low voltage grid have necessitated regulations governing the connection of renewable energy generators to the grid. This was deemed necessary to preserve the integrity and the correct operation of the grid. This paper presents a new architecture of a hybrid phase lock loop circuit topology for synchronizing a single-phase inverter fed from a renewable energy source such as a photovoltaic (PV) generator to the low voltage grid. The system uses a digital phase lock loop (DPLL) architecture, which is based on the arctan phase detector, driving a phase lock loop (PLL) to synchronize a PV inverter with the grid. The proposed system has been tested by simulation using simulink/matlab. The test results demonstrate the ability of the system to synchronize a PV inverter with the grid and to re-establish synchronization following a sudden perturbation in the grid voltage such as a single or a multistep change in phase. The system is digital and can be readily implemented using an FPGA (field programmable gate array) and hence can be easily embedded in a home or small scale single-phase PV inverter.

Maintenance of Three-phase Load Voltage during Single Phase Auto Reclosing in Medium Voltage Radial Distribution Lines

2011 ◽  
Vol 12 (4) ◽  
Author(s):  
Kartik Prasad Basu ◽  
Moley Kutty George
Keyword(s):  
Radial Distribution ◽  
Distribution System ◽  
Single Phase ◽  
Dead Time ◽  
Low Voltage ◽  
Radial Distribution System ◽  
Load Voltage ◽  
Medium Voltage ◽  
Distribution Lines ◽  
Three Phase

Most faults in medium voltage (MV) distribution lines are temporary line to ground (LG) faults. Three-phase auto reclosing (TPAR) is commonly used to remove this fault with temporary disconnection of all the phases. Multi-shot single-phase auto reclosing (SPAR) may also be used to remove the LG fault. But it produces highly unbalanced and low voltage across the load during the reclosure dead time. It is proposed to connect a zigzag winding grounding transformer at the load bus to maintain the 3-phase load voltage when one phase opens during the SPAR. With low value of grounding resistance the 3-phase voltage during the SPAR dead time becomes approximately balanced. Directional over current relays may be used for the protection. Analysis of a MV radial distribution system having a zigzag transformer connected to the remotest load bus is presented with the computation of voltages during the dead time of SPAR.

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