scholarly journals D-PMU and 5G-Network-Based Coordination Control Method for Three-Phase Imbalance Mitigation Units in the LVDN

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2754
Author(s):  
Mengmeng Xiao ◽  
Shaorong Wang ◽  
Zia Ullah
Keyword(s):  
Mobile Networks ◽  
Control Method ◽  
Low Voltage ◽  
Control Unit ◽  
Distribution Networks ◽  
Optimal Operation ◽  
Positive Sequence ◽  
Measurement Unit ◽  
Control Units ◽  
Three Phase

Three-phase imbalance is a long-term issue existing in low-voltage distribution networks (LVDNs), which consequently has an inverse impact on the safe and optimal operation of LVDNs. Recently, the increasing integration of single-phase distributed generations (DGs) and flexible loads has increased the probability of imbalance occurrence in LVDNs. To overcome the above challenges, this paper proposes a novel methodology based on the concept of "Active Asymmetry Energy-Absorbing (AAEA)" utilizing loads with a back-to-back converter, denoted as “AAEA Unit” in this paper. AAEA Units are deployed and coordinated to actively absorb asymmetry power among three phases for imbalance mitigation in LVDNs based on the high-precision, high-accuracy, and real-time distribution-level phasor measurement unit (D-PMU) data acquisition system and the 5th generation mobile networks (5G) communication channels. Furthermore, the control scheme of the proposed method includes three control units. Specifically, the positive-sequence control unit is designed to maintain the voltage of the DC-capacitor of the back-to-back converter. Likewise, the negative-sequence and zero-sequence control units are expected to mitigate the imbalanced current components. A simple imbalanced LVDN is modeled and tested in Simulink/Matlab (MathWorks, US). The obtained results demonstrate the effectiveness of the proposed methodology.

scholarly journals Voltage Protection and Harmonics Cancellation in Low Voltage Distribution Network

2018 ◽  
Vol 7 (04) ◽  
pp. 01-07
Author(s):  
Prof. Amruta Bijwar, Prof. Madhuri Zambre
Keyword(s):  
Direct Current ◽  
Current Distribution ◽  
Low Voltage ◽  
Distribution Network ◽  
Control Unit ◽  
Future Generation ◽  
Distribution Networks ◽  
Current Control ◽  
Voltage Distribution ◽  
Monitor Function

Nowadays low voltage distribution network is considered as worldwide future generation distribution network. But the major concern is harmonics generation and steps taken to cancel those harmonics. In our proposed work, low voltage distribution network is designed with low voltage and harmonics are cancelled in our method. The combination of current control unit and voltage control unit will give extra reliable power solution to increase the required capacity of low voltage grids. The high voltage protection gears are used in worst environment for low voltage and low current distribution network test is preferable to assess a variety of operation uniqueness. Therefore, it has few restrictions in implementation of economic in addition to process methodologies. In our work a 48V direct current base up-scale low voltage distribution network test is urbanized to allow the copy and surveillance of a variety of phenomenon of direct current distribution networks. The proposed system provide stretchy pattern ability by introduce S-connectors and T-connectors module that will be proscribed distantly, and near real time monitor function through by means of a data acquisition system associated toward the nodes. Each connector be able to calculate Power, Voltage and current with up to 250 kHz frequency. To calculate power quality and to understand the performance of the distribution network, frequency analysis is required along with collected data.

scholarly journals Novel Intelligent and Sensorless Proportional Valve Control with Self-Learning Ability

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Bayram Akdemir
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Low Voltage ◽  
Control Unit ◽  
Control Signal ◽  
Learning Ability ◽  
Learning Abilities ◽  
Valve Control ◽  
Self Learning

Linear control is widely used for any fluid or air flows in many automobile, robotics, and hydraulics applications. According to signal level, valve can be controlled linearly. But, for many valves, hydraulics or air is not easy to control proportionally because of flows dynamics. As a conventional solution, electronic driver has up and down limits. After manually settling up and down limits, control unit has proportional blind behavior between two points. This study offers a novel valve control method merging pulse width and amplitude modulation in the same structure. Proposed method uses low voltage AC signal to understand the valve position and uses pulse width modulation for power transfer to coil. DC level leads to controlling the valve and AC signal gives feedback related to core moving. Any amplitude demodulator gives core position as voltage. Control unit makes reconstruction using start and end points to obtain linearization at zero control signal and maximum control signal matched to minimum demodulated amplitude level. Proposed method includes self-learning abilities to keep controlling in hard environmental conditions such as dust, temperature, and corrosion. Thus, self-learning helps to provide precision control for hard conditions.

scholarly journals Time-Series Temperature-Dependent Power Flow Considering Unbalanced Thermoelectric Equivalent Circuits for Underground LV and MV Cables

2021 ◽  
Author(s):  
Evangelos Pompodakis ◽  
Andreas I. Chrysochos ◽  
Arif Ahmed ◽  
Minas C. Alexiadis
Keyword(s):  
Time Series ◽  
Power Flow ◽  
Low Voltage ◽  
Distribution Networks ◽  
Temperature Dependent ◽  
Underground Cables ◽  
Thermal Circuit ◽  
Three Phase ◽  
Homogeneous Soil ◽  
Conductor Temperature

<p>This manuscript proposes a time-series temperature-dependent power flow method for unbalanced distribution networks consisting of underground cables. A thermal circuit model for unbalanced three-phase multi-core cables is developed to estimate the conductor temperature and resistance of Medium and Low Voltage distribution networks. More specifically, a novel approach is proposed to model and estimate the parameters of the three-phase thermal circuit of 3/4-core cables, using the results of Finite Element Method and Particle Swarm Optimization. The proposed approach is generic and can be accurately applied to any kind of 3- or 4-core cables buried in homogeneous or non-homogeneous soil. Furthermore, it is applicable in cases where one or more adjacent cables exist. Using the proposed approach, the conductor temperature of each phase can be individually and precisely calculated even in networks with highly unbalanced loads. The proposed approach is expected to be an important tool for simulating the steady state of unbalanced distribution networks and estimating the conductor temperatures. The proposed thermal circuit is validated using two 4-core LV and one 3-core MV cables buried in different depths in homogeneous or non-homogeneous soil. Time-series power flow for a whole year is performed in a 25-bus unbalanced LV network consisting of multicore underground cables.</p>

scholarly journals On the choosing the installation location the balancing devices in low-voltage distribution electric networks

2021 ◽  
Vol 2094 (5) ◽  
pp. 052012
Author(s):  
I V Naumov ◽  
S V Podyachikh
Keyword(s):  
Power Quality ◽  
Low Voltage ◽  
Experimental Studies ◽  
Distribution Networks ◽  
Electrical Networks ◽  
Process Change ◽  
Electric Networks ◽  
Concentrated Load ◽  
Operating Modes ◽  
Three Phase

Abstract The experimental studies result on the power quality and additional power losses analysis caused by the asymmetric modes occurrence in three-phase four-wire 0.38 kV electrical networks are considered. The operating modes 38 kV networks several types simulation – with power take-off nodes distributed along the power line, and an electric network with a concentrated load is carried out. The programs have been developed that allow to assess the change in indicators characterizing asymmetric modes, as well as programs that allow us to visualize this process change. The most installing special symmetrical devices appropriate places in electric networks with a distributed load (rural electric distribution networks) and concentrated power take-off nodes electric networks (urban electric networks) have been identified to minimize losses and improve the power quality. A numerical studied indicators analysis was performed.

scholarly journals Advanced voltage control method for improving the voltage quality of low-voltage distribution networks with photovoltaic penetrations

2021 ◽  
Vol 4 (S2) ◽  
Author(s):  
Marika Nakamura ◽  
Shinya Yoshizawa ◽  
Hideo Ishii ◽  
Yasuhiro Hayashi
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Low Voltage ◽  
Distribution Network ◽  
Distribution Networks ◽  
Voltage Distribution ◽  
Power Conditioning ◽  
Pv Systems ◽  
Measurement Period ◽  
Voltage Violation

AbstractAs the number of photovoltaic (PV) power generators connected to the distribution grid increases, applications of on-load tap changers (OLTCs), power conditioning systems, and static reactive power compensators are being considered to mitigate the problem of voltage violation in low voltage distribution systems. The reactive power control by power conditioning systems and static reactive power compensators can mitigate steep voltage fluctuations. However, it creates losses in generation opportunities. On the other hand, OLTCs are installed at the bases of distribution lines and can collectively manage the entire system. However, the conventional voltage control method, i.e., the line drop compensation (LDC) method, is not designed for the case in which a large number of PV systems are installed in the distribution network, which results in voltage violations above the limit of the acceptable range. This study proposes a method to determine the optimal LDC control parameters of the voltage regulator, considering the power factor of PV systems to minimize the magnitude of voltage violations based on the voltage profile analysis of low-voltage (LV) distribution networks. Specifically, during a measurement period of several days, the voltages at some LV consumers and pole transformers were measured, and the optimal parameters were determined by analyzing the collected data. The effectiveness of the proposed method was verified through a numerical simulation study using the actual distribution system model under several scenarios of PV penetration rates. Additionally, the difference in the effectiveness of voltage violation reduction was verified in the case where all the LV consumer’s consumer voltage data measured per minute were used as well as in the case where only the maximum and minimum values of the data within the measurement period were used. The results reveal that the proposed method, which operates within the parameters determined by the voltage analysis of the LV distribution network, is superior to the conventional method. Furthermore, it was found that even if only the maximum and minimum values of the measurement data were used, an effective voltage violation reduction could be expected.

scholarly journals Three-Phase Unbalanced Optimal Power Flow Using Holomorphic Embedding Load Flow Method

2019 ◽  
Vol 11 (6) ◽  
pp. 1774 ◽  
Author(s):  
Bharath Rao ◽  
Friederich Kupzog ◽  
Martin Kozek
Keyword(s):  
Power Flow ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Distribution Networks ◽  
Optimization Method ◽  
Load Flow ◽  
Flow Method ◽  
Optimal Power ◽  
Three Phase ◽  
Holomorphic Embedding

Distribution networks are typically unbalanced due to loads being unevenly distributed over the three phases and untransposed lines. Additionally, unbalance is further increased with high penetration of single-phased distributed generators. Load and optimal power flows, when applied to distribution networks, use models developed for transmission grids with limited modification. The performance of optimal power flow depends on external factors such as ambient temperature and irradiation, since they have strong influence on loads and distributed energy resources such as photo voltaic systems. To help mitigate the issues mentioned above, the authors present a novel class of optimal power flow algorithm which is applied to low-voltage distribution networks. It involves the use of a novel three-phase unbalanced holomorphic embedding load flow method in conjunction with a non-convex optimization method to obtain the optimal set-points based on a suitable objective function. This novel three-phase load flow method is benchmarked against the well-known power factory Newton-Raphson algorithm for various test networks. Mann-Whitney U test is performed for the voltage magnitude data generated by both methods and null hypothesis is accepted. A use case involving a real network in Austria and a method to generate optimal schedules for various controllable buses is provided.

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