The Impact of the Lightning Surge on SiC-based Medium-voltage Three-phase Four-wire Grid-connected Converters

2021 ◽  
Author(s):  
Haiguo Li ◽  
Yiwei Ma ◽  
Shiqi Ji ◽  
Fred Wang
Keyword(s):  
Wire Grid ◽  
Medium Voltage ◽  
Three Phase ◽  
Grid Connected Converters ◽  
The Impact

scholarly journals A Simple Method to Validate Power Loss in Medium Voltage SiC MOSFETs and Schottky Diodes Operating in a Three-Phase Inverter

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4773
Author(s):  
Jacek Rąbkowski ◽  
Hubert Skoneczny ◽  
Rafał Kopacz ◽  
Przemysław Trochimiuk ◽  
Grzegorz Wrona
Keyword(s):  
Power Loss ◽  
Schottky Diodes ◽  
Duty Ratio ◽  
Inductive Load ◽  
Simple Method ◽  
Phase Inverter ◽  
Medium Voltage ◽  
Three Phase ◽  
The Impact ◽  
Three Phase Inverter

This paper presents an original method of power loss validation in medium-voltage SiC MOSFET (metal–oxide–semiconductor field-effect transistor) modules of a three-phase inverter. The base of this method is a correct description of the on-state performance of the diodes and the transistors in a PWM (pulse width modulation)-controlled inverter phase leg. Combined electro-thermal calculations are applied to precisely estimate the losses in the power devices and then, to find the suitable circuit parameters of a test circuit to emulate these conditions. A simple square-wave-controlled half-bridge with an inductive load enables the electrical and thermal stresses comparable to these in the inverter, and moreover, provided equations that confirmed the possibility of balancing the load between the diodes and the transistors. The circuit with 3.3 kV SiC MOSFETs was tested to verify the impact of selected parameters on power losses with the main focus on duty ratio. The same module was applied, in addition to an inductive load (3 × 112 μH) and two sets of DC-link capacitors (750 μF), to validate a phase leg of a 220 kVA inverter. In spite of a significantly apparent power, the active power delivered from the DC supply settled around 1 kW, which was enough to emulate 390 W of losses in two transistors and diodes.

scholarly journals A Three-Phase Weather-Dependent Power Flow Approach for 4-Wire Multi-Grounded Unbalanced Microgrids with Bare Overhead Conductors

2020 ◽  
Author(s):  
Evangelos Pompodakis
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Flow Analysis ◽  
Single Layer ◽  
Distribution Networks ◽  
Medium Voltage ◽  
The Core ◽  
Magnetic Effects ◽  
Three Phase ◽  
The Impact

<p><b>Conventional power flow (CPF) algorithms assume that the network resistances and reactances remain constant regardless of the weather and loading conditions. Although the impact of the weather in power flow analysis has been recently investigated via the weather-dependent power flow (WDPF) approaches, the magnetic effects in the core of ACSR conductors have not been explicitly considered. ACSR conductors are widely used in distribution networks. Therefore, this manuscript proposes a three-phase weather-dependent power flow algorithm for 4-wire multi-grounded unbalanced microgrids (MGs), which takes into consideration the impact of weather as well as the magnetic effects in the core of ACSR conductors. It is shown that the magnetic effects in the core can significantly influence the power flow results, especially for networks composed of single-layer ACSR conductors. Furthermore, the proposed algorithm explicitly considers the multi-grounded neutral conductor, thus it can precisely simulate unbalanced low voltage (LV) and medium voltage (MV) networks. In addition, the proposed approach is generic and can be applied in both grid-connected and islanded networks. Simulations conducted in a 25-Bus unbalanced LV microgrid highlight the accuracy and benefit of the proposed approach. </b></p>

scholarly journals A Three-Phase Weather-Dependent Power Flow Approach for 4-Wire Multi-Grounded Unbalanced Microgrids with Bare Overhead Conductors

2020 ◽  
Author(s):  
Evangelos Pompodakis
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Flow Analysis ◽  
Single Layer ◽  
Distribution Networks ◽  
Medium Voltage ◽  
The Core ◽  
Magnetic Effects ◽  
Three Phase ◽  
The Impact

<p><b>Conventional power flow (CPF) algorithms assume that the network resistances and reactances remain constant regardless of the weather and loading conditions. Although the impact of the weather in power flow analysis has been recently investigated via the weather-dependent power flow (WDPF) approaches, the magnetic effects in the core of ACSR conductors have not been explicitly considered. ACSR conductors are widely used in distribution networks. Therefore, this manuscript proposes a three-phase weather-dependent power flow algorithm for 4-wire multi-grounded unbalanced microgrids (MGs), which takes into consideration the impact of weather as well as the magnetic effects in the core of ACSR conductors. It is shown that the magnetic effects in the core can significantly influence the power flow results, especially for networks composed of single-layer ACSR conductors. Furthermore, the proposed algorithm explicitly considers the multi-grounded neutral conductor, thus it can precisely simulate unbalanced low voltage (LV) and medium voltage (MV) networks. In addition, the proposed approach is generic and can be applied in both grid-connected and islanded networks. Simulations conducted in a 25-Bus unbalanced LV microgrid highlight the accuracy and benefit of the proposed approach. </b></p>

scholarly journals A Three-Phase Weather-Dependent Power Flow Approach for 4-Wire Multi-Grounded Unbalanced Microgrids with Bare Overhead Conductors

2020 ◽  
Author(s):  
Evangelos Pompodakis
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Flow Analysis ◽  
Single Layer ◽  
Distribution Networks ◽  
Medium Voltage ◽  
The Core ◽  
Magnetic Effects ◽  
Three Phase ◽  
The Impact

<p><b>Conventional power flow (CPF) algorithms assume that the network resistances and reactances remain constant regardless of the weather and loading conditions. Although the impact of the weather in power flow analysis has been recently investigated via the weather-dependent power flow (WDPF) approaches, the magnetic effects in the core of ACSR conductors have not been explicitly considered. ACSR conductors are widely used in distribution networks. Therefore, this manuscript proposes a three-phase weather-dependent power flow algorithm for 4-wire multi-grounded unbalanced microgrids (MGs), which takes into consideration the impact of weather as well as the magnetic effects in the core of ACSR conductors. It is shown that the magnetic effects in the core can significantly influence the power flow results, especially for networks composed of single-layer ACSR conductors. Furthermore, the proposed algorithm explicitly considers the multi-grounded neutral conductor, thus it can precisely simulate unbalanced low voltage (LV) and medium voltage (MV) networks. In addition, the proposed approach is generic and can be applied in both grid-connected and islanded networks. Simulations conducted in a 25-Bus unbalanced LV microgrid highlight the accuracy and benefit of the proposed approach. </b></p>

scholarly journals Improving PV Resilience by Dynamic Reconfiguration in Distribution Grids: Problem Complexity and Computation Requirements

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 830
Author(s):  
Filipe F. C. Silva ◽  
Pedro M. S. Carvalho ◽  
Luís A. F. M. Ferreira
Keyword(s):  
Distributed Generation ◽  
Optimal Solution ◽  
Dynamic Reconfiguration ◽  
Scheduling Problem ◽  
Low Carbon ◽  
Distribution Grid ◽  
Medium Voltage ◽  
Classical Computing ◽  
The Impact ◽  
Distribution Grids

The dissemination of low-carbon technologies, such as urban photovoltaic distributed generation, imposes new challenges to the operation of distribution grids. Distributed generation may introduce significant net-load asymmetries between feeders in the course of the day, resulting in higher losses. The dynamic reconfiguration of the grid could mitigate daily losses and be used to minimize or defer the need for network reinforcement. Yet, dynamic reconfiguration has to be carried out in near real-time in order to make use of the most updated load and generation forecast, this way maximizing operational benefits. Given the need to quickly find and update reconfiguration decisions, the computational complexity of the underlying optimal scheduling problem is studied in this paper. The problem is formulated and the impact of sub-optimal solutions is illustrated using a real medium-voltage distribution grid operated under a heavy generation scenario. The complexity of the scheduling problem is discussed to conclude that its optimal solution is infeasible in practical terms if relying upon classical computing. Quantum computing is finally proposed as a way to handle this kind of problem in the future.

scholarly journals Quadrature Voltage Compensation in the Isolated Multi-Modular Converter

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 529
Author(s):  
Cristian Verdugo ◽  
Jose Ignacio Candela ◽  
Pedro Rodriguez
Keyword(s):  
Control Strategy ◽  
Phase Voltage ◽  
Multilevel Converters ◽  
Photovoltaic Panels ◽  
Circulating Current ◽  
Three Phase ◽  
Voltage Compensation ◽  
Wide Range ◽  
Modular Converter ◽  
The Impact

Series connections of modules in cascaded multilevel converters are prone to power imbalances due to voltage differences on their DC side. When modules are connected to direct current (DC) sources, such as photovoltaic panels, the capability of withstanding power imbalances is crucial for generating the maximum power. In order to provide a possible solution for this requirement, this paper proposes a control strategy called Quadrature Voltage Compensation, which allows a wide range of power imbalances. The proposed control strategy regulates the power by introducing a circulating current between the arms and a phase angle in the output voltage. The impact of the circulating current and its effect on the phase voltage are studied. To highlight the features of the proposed strategy, an analytical model based on vector superposition is also described, demonstrating the strong capability of tolerating power differences. Finally, to validate the effectiveness of the Quadrature Voltage Compensation, simulation and experimental results are presented for a three-phase isolated multi-modular converter.

Design and Implementation of Wireless Voltage Monitoring System Based on Zigbee

2017 ◽  
Vol 12 (3) ◽  
pp. 83-96 ◽  
Author(s):  
Luo Xiaohui
Keyword(s):  
Monitoring System ◽  
Single Phase ◽  
Low Cost ◽  
Moving Average ◽  
Voltage Sensor ◽  
Wireless Transmission ◽  
Phase Voltage ◽  
Medium Voltage ◽  
Wireless Monitoring ◽  
Three Phase

This paper proposed a low cost wireless monitoring system based on ZigBee wireless transmission, and designed a new floating voltage sensor which is suitable for the monitoring of medium voltage and high voltage(MV/HV) public equipment. The system used TI-CC2530 as the controller, proposed a new moving average voltage sensing(MAVS) algorithm by reasonable assumptions, and adopted algorithms to perform the theoretical analysis for the single phase and three-phase voltage. At last, the author carried out a practical experiment on the wireless floating voltage sensor under the voltage up to 30kV, the experimental results showed that the proposed low cost wireless sensor can achieve a good voltage monitoring function, and the error is less than 3%.

scholarly journals Four-Level Three-Phase Inverter With Reduced Component Count for Low and Medium Voltage Applications

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 35151-35163
Author(s):  
Ahmed Salem ◽  
Huynh Van Khang ◽  
Kjell G. Robbersmyr
Keyword(s):  
Phase Inverter ◽  
Medium Voltage ◽  
Three Phase ◽  
Three Phase Inverter

scholarly journals Reaching consensus on reporting patient and public involvement (PPI) in research: methods and lessons learned from the development of reporting guidelines

BMJ Open ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. e016948 ◽  
Author(s):  
Jo Brett ◽  
Sophie Staniszewska ◽  
Iveta Simera ◽  
Kate Seers ◽  
Carole Mockford ◽  
...  
Keyword(s):  
Public Involvement ◽  
Evidence Base ◽  
Patient And Public Involvement ◽  
Lessons Learned ◽  
Reporting Guidelines ◽  
Consensus Development ◽  
Face To Face ◽  
Three Phase ◽  
Health And Social Care ◽  
The Impact

IntroductionPatient and public involvement (PPI) is inconsistently reported in health and social care research. Improving the quality of how PPI is reported is critical in developing a higher quality evidence base to gain a better insight into the methods and impact of PPI. This paper describes the methods used to develop and gain consensus on guidelines for reporting PPI in research studies (updated version of the Guidance for Reporting Patient and Public Involvement (GRIPP2)).MethodsThere were three key stages in the development of GRIPP2: identification of key items for the guideline from systematic review evidence of the impact of PPI on health research and health services, a three-phase online Delphi survey with a diverse sample of experts in PPI to gain consensus on included items and a face-to-face consensus meeting to finalise and reach definitive agreement on GRIPP2. Challenges and lessons learnt during the development of the reporting guidelines are reported.DiscussionThe process of reaching consensus is vital within the development of guidelines and policy directions, although debate around how best to reach consensus is still needed. This paper discusses the critical stages of consensus development as applied to the development of consensus for GRIPP2 and discusses the benefits and challenges of consensus development.

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