Modeling and Control of Grid-Connected Photovoltaic Power Plant With Fault Ride-Through Capability

According to modern grid codes (GCs), high penetration of photovoltaic power plants (PVPPs) to the utility grid requires a reliable PV generation system by achieving fault ride-through (FRT) requirements. In order to meet these requirements, there are two major issues that should be addressed to keep the inverter connected during grid fault. The two issues are the ac over-current and dc-link over-voltage that may cause disconnection or damage to the grid inverter. In this paper, the control of single-stage PVPP inverters is developed to address these issues and enhance FRT capability. The proposed control scheme introduces the dc brake chopper circuit and current limiter to protect the inverter and ride through the fault smoothly with no perceptible overcompensation. A 1.5 MW PVPP connected into the Malaysian grid and modeled in simulink is utilized to explain the proposed control scheme. The simulation results presented demonstrate the effectiveness of the overall proposed control strategy to ride through different types of faults and to help to ensure the safety of the system equipmen

Grid‐connected photovoltaic power plants: A review of the recent integration requirements in modern grid codes

The high integration of photovoltaic power plants (PVPPs) has started to affect the operation, stability, and security of utility grids. Thus, many countries have established new requirements for grid integration of solar photovoltaics to address the issues in stability and security of the power grid. In this paper, a comprehensive study of the recent international grid codes requirement concerning the penetration of PVPPs into electrical grids is provided. Firstly, the paper discusses the trends of PVPPs worldwide and the significance of improving grid codes' requirements. In addition, the comparison of common requirements covered in the majority of international grid codes considers high‐ and low‐voltage ride‐through capabilities, voltage and frequency regulation, and active and reactive power support requirements. Finally, a broad discussion on the compliance technology challenges and global harmonization of international grid codes that the PVPPs have to address is presented. The study summarizes the most recent international regulation regarding photovoltaic integration and research findings on the compliance of these regulations and proposed recommendations for future research. It also can assist power system operators to compare their existing requirements with other universal operators or establish their own regulations for the first time. Additionally, this research assists photovoltaic manufacturers and developers to get more accurate understanding from the recent global requirements enforced by the modern grid codes

Modeling and Ddynamics Study of Large Scale PV System Connected Malaysian Grid under Different Fault Conditions

The installation of photovoltaic power plants and integration with electric grid has become more widespread. Asnthere is a significant increase in the size and capacity of grid-connected power plants, the stability and reliability of the grid become more important. A 1.5 MW PV station connected to the distribution side of the Malaysian grid via a voltage source inverter is modeled and simulated using Matlab/Simulink. This study presents the modeling of PV module behavior and characteristics based on the mathematical model equivalent circuit. The Simulink was run to simulate PV array sizing depending on perturb and observed maximum power point technique to enhance the efficiency of modules, and obtain maximum available power using variable perturbation step size dependent on power changes. The simulation result was matched to the results of sizing calculation. The inverter control system modeling and park transformation were carried out. Phase locked loop was used to track the grid frequency and voltage. The Malaysian grid-connected PV system is designed and modeled according to the regulations and guidelines of Tenaga Nasional Berhad concerning grid-integration of PV power generation system to LV and MV networks. Finally, this paper analyzes the dynamic response of the proposed PV plant under various types of symmetrical and non-symmetrical grid faults. The results indicated that the short circuit faults in the distribution grid side had disturbing effects on the optimal operation performance of PV systems. Whereas, the influence of grid faults depends on the fault type. In addition to that, the simulation result proved that the symmetrical fault has higher impact on PV system operationmthan non-symmetrical faults

Sizing and Design of PV Array for Photovoltaic Power Plant Connected Grid Inverter

Over the past few years, installation of photovoltaic power plants (PVPPs) are considered as one of the most promising technologies at many of countries around the world, in order to meet the growing demand of energy. The DC side (PV generators and MPPT) of a 1.5 MW PV power plant connected to the inverter is modeled and simulated using Matlab/Simulink. The sizing of the suggested PVPP is achieved, such as array sizing and enhanced perturb and observe maximum power point tracking (MPPT) technique, in order to overcome the disadvantages of conventional method such as oscillation and slowly tracking under sudden change of atmospheric conditions. The MATLAB/Simulink was run to simulate the PV array sizing and its characteristics depending on enhanced MPPT technique to improve the efficiency of the modules and getting maximum available power. The simulation result has been matched the sizing theoretical calculation results

Modeling and design of photovoltaic power plant connected to the MV side of Malaysian grid with TNB technical regulation compatibility

Increasing penetration of photovoltaic power plants (PVPPs) to the electrical grid leads to continuous evaluation of grid interconnection requirements. For this purpose, Malaysian grid representative from Tenaga Nasional Berhad (TNB) issued technical rules and requirements concerning the connection of photovoltaic system to low and medium voltage networks. The objective of this paper is to design a large-scale PV plant connected to the MV side of the Malaysian grid, taking the compliance of TNB technical regulations into consideration. In this study, the PV plant has been modeled using MATLAB/Simulink with nominal rated peak power of 1.5 MW. The sizing of suggested PV system is achieved in which the simulation results matched the sizing calculation results. The paper focuses on the model’s ability to reflect the important requirements that a PVPP should have based on TNB rules for MV connection. The results show that the proposed PVPP is compatible with TNB requirements

Harmonic distortion and voltage imbalance study of photovoltaic power plant connected to the Malaysian grid

This paper presents power quality analysis on the effects of large-scale photovoltaic power plant (PVPP) connected to the distribution system of Malaysian grid. For this purpose, the PVPP system with a capacity of 1.5 MW is connected to the medium voltage level of the distribution network through a single-stage voltage source inverter (VSI). Power quality issues at connection point such as current and voltage harmonics distortion and voltage imbalance have been studied based on the standard requirements especially Malaysian standards at different levels of solar irradiation. This analysis is very useful to help researchers and grid operators to study the effects of power quality problems concerning gridconnected PVPP. It can be clearly seen from the measured results that the harmonic distortion and voltage imbalance of the proposed PVPP can meet the Malaysian distribution grid code and national grid standard requirements

A New Approach To The Solution Of Economic Dispatch Using Genetic Algorithm

Economic dispatch is the process of finding the optimal generation scheduling of a number of electricity generation facilities to meet the load of the system at lowest possible cost, subject to transmission and operational constraints on the system. The main idea of this paper focuses on the application of genetic algorithm in order to identify the best solution to an economic dispatch problem by using a new approach depending on Bmn coefficients and arithmetic crossover of the genetic algorithm. In this study, the proposed method solves the economic dispatch problem of three generator units whilst taking into consideration the coefficient losses to find the most important factors in electrical generation, which are the output power and total cost. The results of this study are compared with the classical optimization calculation techniques, and it is found that the results were almost equal. The MATLAB simulation is run to demonstrate clearly the effectiveness of the new genetic algorithm approach as a very important method in the solution of economic dispatch problems

Modeling And Simulation Of Photovoltaic Module With Enhanced Perturb And Observe MPPT Algorithm Using Matlab/Simulink

Modeling and analysis of photovoltaic (PV) system is substantial for designers of solar power plants to do a yield investigation that precisely predicts the expected output power under changing weather conditions. The model allows the prediction of PV module’s behaviour and characteristics based on the mathematical model equivalent circuit using Matlab/Simulink platform under different temperature and solar radiation readings. The second part of this paper proposes an enhancement to the conventional perturb and observe (P&O) maximum power point tracking (MPPT) technique in order to overcome the disadvantages of this method such as oscillation and slow tracking under sudden change of atmospheric conditions. The proposed method suggested that utilizing a variable perturbation step size depending on power changes instead of constant step size which is used in conventional P&O algorithm in order to ensure that the solar energy is captured and converted as much as possible. The simulation results are compared with that of traditional P&O to demonstrate the effectiveness of the proposed method

Low Voltage Ride-Through Capability Control for Single-Stage Inverter-Based Grid-Connected Photovoltaic Power Plant

The low voltage ride-through (LVRT) capability is one of the challenges faced by the integration of large-scale photovoltaic (PV) power stations into electrical grid which has not been fully investigated. Therefore, this paper presents a comprehensive control strategy of single-stage PV power plant to enhance the LVRT capability based on the Malaysian standards and modern grid codes connection requirements. The proposed control overcomes the problems of dc-link over-voltage and ac over-current that may cause disconnection or damage to the inverter. For this purpose, dc-chopper brake controller and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively. This control strategy can also ensure the reactive power support through the injection of reactive current according to the standard requirements as soon as the voltage sag is detected. Furthermore, to keep the power balance between both sides of the inverter, PV array can generate possible amount of active power according to the rating of grid inverter and voltage sag depth by the operating in different modes. The results illustrate that the proposed control strategy is effective, not only to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults