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.

scholarly journals Equivalent Model of a Three Phase System of Photovoltaic Generation to Analyze Voltage Variations in a Radial Distribution System

2020 ◽  
Vol 25 (2) ◽  
pp. 205-215
Author(s):  
Juan Camilo Toro-Cadavid ◽  
Carlos Andrés Ramos-Paja ◽  
Andrés Julián Saavedra-Montes
Keyword(s):  
Radial Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Single Phase ◽  
Parameters Estimation ◽  
Photovoltaic System ◽  
Photovoltaic Generation ◽  
Radial Distribution System ◽  
Three Phase ◽  
Photovoltaic Generators

In this paper, the modelling of a three-phase photovoltaic system, for analyzing voltage variation in a radial distribution system, is presented. The radial distribution system is represented by a benchmark which is widely used in the analysis of distribution systems with distributed generation, and electrical microgrids. The parameters estimation of this model is performed by selecting the aerial distribution of conductors and then calculating the sequence components. Moreover, a model of a three-phase photovoltaic generation system for analyzing voltage variations is proposed. The model represents an array of photovoltaic panels, a dc/dc converter with its control system, and a three-phase inverter. The software MATLAB/Simulink is chosen to simulate both the distribution and the photovoltaic systems. All the components of the three-phase photovoltaic system are parametrized with information of commercial equipment. To facilitate the implementation of the system model in the analysis program, reduced models of its components are selected. Finally, the proposed model of the three-phase photovoltaic system is validated by simulating single-phase faults along the feeder and changes of irradiance over the photovoltaic generators and observing the voltage behavior in one node of the distribution system. The results show that irradiance changes and single-phase faults affect the voltage behavior depending on the photovoltaic penetration level and the generators location.

scholarly journals Power-Flow Development Based on the Modified Backward-Forward for Voltage Profile Improvement of Distribution System

2016 ◽  
Vol 6 (5) ◽  
pp. 2005
Author(s):  
Suyanto Suyanto ◽  
Citra Rahmadhani ◽  
Ontoseno Penangsang ◽  
Adi Soeprijanto
Keyword(s):  
Distributed Generation ◽  
Radial Distribution ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Network ◽  
Flow Simulation ◽  
Voltage Profile ◽  
Radial Distribution System ◽  
Flow Development ◽  
Three Phase

<p>Unbalanced three-phase radial distribution system has a complex problem in power system. It has many branches and it is sometimes voltage profile’s not stable at every end branches. For improvement of voltage profile, it can be performed by penetrating of a distributed generation models. Information of voltage profile can be gained by study of power flow.  The Modified Backward-Forward is one of the most widely used methods of development of power flow and has been extensively used for voltage profile analysis. In this paper, a study of power flow based on the Modified Backward-Forward method was used to capture the complexities of unbalanced three phase radial distribution system in the 20 kV distribution network in North Surabaya city, East Java, Indonesia within considering distributed generation models. In summary, for the informants in this study, the Modified Backward-Forward method has had quickly convergence and it’s just needed 3 to 5 iteration of power flow simulation which’s compared to other power flow development methods. Distributed Generation models in the modified the modified 34 BUS IEEE system and 20 kV distribution network has gained voltage profile value on limited range. One of the more significant findings to emerge from this development is that the Modified Backward-Forward method has average of error voltage about 0.0017 % to 0.1749%.</p>

scholarly journals Low-Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yongheng Yang ◽  
Frede Blaabjerg
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Control Method ◽  
Low Voltage ◽  
Photovoltaic System ◽  
Pv System ◽  
Pv Systems ◽  
Low Voltage Ride Through ◽  
Three Phase ◽  
Future Challenges

The progressive growing of single-phase photovoltaic (PV) systems makes the Distribution System Operators (DSOs) update or revise the existing grid codes in order to guarantee the availability, quality, and reliability of the electrical system. It is expected that the future PV systems connected to the low-voltage grid will be more active with functionalities of low-voltage ride-through (LVRT) and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in a low-voltage ride-through operation in order to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability with a satisfactory performance based on the grid requirements for three-phase renewable energy systems.

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