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.

scholarly journals Fault Ride-Through Capability Enhancement for Microinverter Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Sajad Arab Ansari ◽  
Amir Reza Mizani ◽  
Siamak Ashouri ◽  
Javad Shokrollahi Moghani
Keyword(s):  
Power Systems ◽  
Single Phase ◽  
Low Voltage ◽  
Pv Systems ◽  
Low Voltage Ride Through ◽  
Fault Ride Through ◽  
Three Phase ◽  
Future Challenges ◽  
Wind Power Systems ◽  
Conduction Mode

Due to the fast growth of single-phase grid-connected photovoltaic (PV) systems, the existing grid codes are expected to be modified to guarantee the availability, quality, and reliability of the electrical system. Therefore, the future single-phase PV systems should become smarter and support low voltage ride-through (LVRT) capability, which are required for three-phase wind power systems. In this paper, the operation principle of a flyback inverter in a low-voltage ride-through operation is demonstrated in order to map future challenges. The steady state performance of the flyback inverter under voltage rise and drop conditions at boundary conduction mode (BCM) and discontinues conduction mode (DCM) is studied theoretically. The simulation results of the flyback inverter for various grid faults are presented to verify the theoretical analyses. The results indicate the fact that the flyback inverter at BCM condition can provide LVRT capability for photovoltaic microinverter applications in distributed generation (DG) systems, even though it does not need any auxiliary control branches and any limitations in components design.

scholarly journals Modeling and Design of the Vector Control for a Three-Phase Single-Stage Grid-Connected PV System with LVRT Capability according to the Spanish Grid Code

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2899 ◽  
Author(s):  
Alexis B. Rey-Boué ◽  
N. F. Guerrero-Rodríguez ◽  
Johannes Stöckl ◽  
Thomas I. Strasser
Keyword(s):  
Vector Control ◽  
Reactive Power ◽  
Low Voltage ◽  
Single Stage ◽  
Photovoltaic System ◽  
Lookup Table ◽  
Voltage Sags ◽  
Pv System ◽  
Low Voltage Ride Through ◽  
Three Phase

This article deals with the vector control in dq axes of a three-phase grid-connected photovoltaic system with single-stage topology and low-voltage-ride-through capability. The photovoltaic generator is built using an array of several series-parallel Suntech PV modules and is modeled as a Lookup Table (two-dimensional; 2-D). The requirements adopted when grid voltage sags occur are based in both the IEC 61400-21 European normative and the allowed amount of reactive power to be delivered according to the Spanish grid code, which avoids the disconnection of the inverter under grid faults by a limitation in the magnitude of the three-phase output inverter currents. For this, the calculation of the positive- and negative-sequences of the grid voltages is made and a conventional three-phase Phase-Locked Loop is used for the inverter-grid synchronization, allowing the control of the active and reactive powers solely with the dq components of the inverter currents. A detailed enhanced flowchart of the control algorithm with low-voltage-ride-through capability is presented and several simulations and experiments using Matlab/SIMULINK and the Controller Hardware-in-the-Loop simulation technique, respectively, are run for several types of one- and three-phase voltage sags in order to validate its behavior.

scholarly journals The Modified Control Method for the Single-Stage Three-Phase GridConnected Photovoltaic System

2013 ◽  
Vol 16 (4) ◽  
pp. 19-32
Author(s):  
Dzung Quoc Pham ◽  
Vu Truong Dan Nguyen ◽  
Khoa Dinh Le ◽  
Anh Bao Nguyen ◽  
Diep Chi Le
Keyword(s):  
High Efficiency ◽  
Control Method ◽  
Input Power ◽  
Single Stage ◽  
Photovoltaic System ◽  
State Equations ◽  
Pv System ◽  
Pv Systems ◽  
Three Phase ◽  
High Efficient

Single-stage topology and the maximum power point tracking (MPPT) algorithm have advantages such as simple configuration and high efficiency in grid-connected photovoltaic (PV) systems. In conventional systems, current and voltage sensors of PV system are normally used for MPPT. This paper presents a modified control algorithm for the single-stage three-phase grid-connected PV system without PV current sensor with a variable step MPP-tracker. This algorithm is not derived from complex state equations and is not dependent on any circuit parameters. It simply calculates the output power of the inverter to replace the input power of the PV systems in the MPPT algorithm. The modified algorithm is simulated by using Matlab/Simulink software and implemented in the experimental prototype. With the single-stage configuration and PV current sensorless method, the prototype is suitable for lowcost high efficient implementation in the practice.

scholarly journals Fuzzy Logic Control for Low-Voltage Ride-Through Single-Phase Grid-Connected PV Inverter

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4796 ◽  
Author(s):  
Eyad Radwan ◽  
Mutasim Nour ◽  
Emad Awada ◽  
Ali Baniyounes
Keyword(s):  
Fuzzy Logic ◽  
Output Power ◽  
Single Phase ◽  
Reactive Power ◽  
Low Voltage ◽  
Operating Conditions ◽  
Pv System ◽  
Utilization Factor ◽  
Low Voltage Ride Through ◽  
Active And Reactive Power

This paper presents a control scheme for a photovoltaic (PV) system that uses a single-phase grid-connected inverter with low-voltage ride-through (LVRT) capability. In this scheme, two PI regulators are used to adjust the power angle and voltage modulation index of the inverter; therefore, controlling the inverter’s active and reactive output power, respectively. A fuzzy logic controller (FLC) is also implemented to manage the inverter’s operation during the LVRT operation. The FLC adjusts (or de-rates) the inverter’s reference active and reactive power commands based on the grid voltage sag and the power available from the PV system. Therefore, the inverter operation has been divided into two modes: (i) Maximum power point tracking (MPPT) during the normal operating conditions of the grid, and (ii) LVRT support when the grid is operating under faulty conditions. In the LVRT mode, the de-rating of the inverter active output power allows for injection of some reactive power, hence providing voltage support to the grid and enhancing the utilization factor of the inverter’s capacity. The proposed system was modelled and simulated using MATLAB Simulink. The simulation results showed good system performance in response to changes in reference power command, and in adjusting the amount of active and reactive power injected into the grid.

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 SPACE VECTOR BASED THREE PHASE GRID CONNECTED PHOTOVOLTAIC SYSTEM

2012 ◽  
pp. 58-63
Author(s):  
T. NARASIMHA PRASAD ◽  
V. LAKSHMI DEVI
Keyword(s):  
Distributed Generation ◽  
Fault Analysis ◽  
Photovoltaic System ◽  
System Optimum ◽  
Pv System ◽  
Pv Systems ◽  
Three Phase ◽  
New Energy ◽  
Static Performance ◽  
Transmission And Distribution

Solar energy has become a very potential new energy; Connected directly with grid-connected photovoltaic (PV) systems does not require bulk and lossy battery. Distributed generation and on-site supply of PV system reduces losses of transmission and distribution, and mitigates environment pollution. This paper establishes a Dynamic model of grid-connected PV system by Matlab/Simulink with d-and q-axis as coordinates which is synchronously rotating with the grid voltage to reflect the characteristics of the system accurately. Based on the accurate modeling system, optimum control and fault analysis are studied. The simulation and analysis verify the effectiveness of the proposed algorithm, and demonstrate that the proposed control system has good static performance.

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.

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