Wind Turbine and Photovoltaic Hybrid Generations under Extreme Operating Gust

A micro-grid consisting of a 300kW wind turbine and a 40kW photovoltaic array is investigated under extreme operating gust (EOG) wind scenarios. The micro-grid is connected to the 380-V utility through a utility-side converter using natural-frame control, which provides a constant voltage of the DC link between the micro-grid and utility. The impact of the extreme gust wind variations on the micro-grid performance is studied for variable speed wind energy system equipped with a squirrel-cage induction generator. The Hurghada city, Red Sea, Egypt is taken as a case study for the wind speed profile. A detailed model of extreme gust-wind speed variation is implemented and simulated using PSIM commercial software package, based on climate characteristics of Hurghada city. The indirect rotor field oriented control (FOC) method is implemented to the generator-side converter to keep the system stable under the extreme gust wind conditions and to control the squirrel-cage induction generator (SCIG) speed for maximum power-point tracker (MPPT) regime. Power quality of the utility-side converter in terms of operation at different power factors, voltage value and THD are verified

Optimization Based on Movable Damped Wave Algorithm for Design of Photovoltaic/ Wind/ Diesel/ Biomass/ Battery Hybrid Energy Systems

The actual energetic situation has several challenges such as pollution, the rarefaction of fossil fuel and the dangers of nuclear. Renewable sources are proposed as a solution and suggested, such as a cost-effectiveness system. The paper deals with the problem of feeding a domestic load with electricity which should respect the ecologies factors, so this work is a design problem of the hybrid renewable energy systems; PV/biomass, PV/diesel/battery, PV/wind/diesel/battery, and wind/diesel/battery to choose the best one of them which feed the load with the lowest cost. The study’s goal is to design a microgrid system by the minimization of the total investment cost with respect to the required technical factor, the minimum allowed renewable energy fraction, and the minimum allowed availability factor. The methodology flowed utilizes frameworks based on a recent algorithm called Movable damped wave algorithm (MDVP). The proposed optimization algorithm is compared with other algorithms to prove its efficacy which are; the artificial electric field algorithm (AEFA), harris hawks optimization (HHO), and the grey wolf optimizer (GWO). The project case study is investigated in Al-Majmaah, Saudi Arabia. The contribution of this work is implementing a recent algorithm that proves its efficacy and finding the best microgrid configuration following many investigations and comparisons. The results confirm that the MDVP is better compared to the other algorithms, its computational time is fast, and its convergence is good; otherwise, the PV/biomass is considered the best configuration in the area of study with a size of 237.698 m2 from PV panel and 954.097 t/year of biomass, which obtained the best Net Present Cost (NPC) of $299504, and a cost of energy (LCOE) assumed as$0.228/kW. A sensitivity analysis is applied to prove the effect of size variation on project factors. The simple observation, by the way, is that any change in the PV size affects the output factors

Design of a Partially Grid-Connected Photovoltaic Microgrid Using IoT Technology

This study describes the design and control algorithms of an IoT-connected photovoltaic microgrid operating in a partially grid-connected mode. The proposed architecture and control design aim to connect or disconnect non-critical loads between the microgrid and utility grid. Different components of the microgrid, such as photovoltaic arrays, energy storage elements, inverters, solid-state transfer switches, smart-meters, and communication networks were modeled and simulated. The communication between smart meters and the microgrid controller is designed using LoRa communication protocol for the control and monitoring of loads in residential buildings. An IoT-enabled smart meter has been designed using ZigBee communication protocol to evaluate data transmission requirements in the microgrid. The loads were managed by a proposed under-voltage load-shedding algorithm that selects suitable loads to be disconnected from the microgrid and transferred to the utility grid. The simulation results showed that the duty cycle of LoRa and its bit rate can handle the communication requirements in the proposed PV microgrid architecture

Fault analysis of multiphase distribution systems using symmetrical components

The paper presents a new approach for performing the fault analysis of multiphase distribution networks based on the symmetrical components. The multiphase distribution system is represented by an equivalent three-phase system; hence, the single-phase and two-phase line segments are represented in terms of their sequence values. The proposed technique allows the state of the art short-circuit analysis solvers to analyze unbalanced distribution networks. The fault currents calculated using the proposed technique is compared with the phase components short-circuit analysis solver. The obtained results for the IEEE radial test feeders show that the proposed technique is accurate. Based on the proposed method, the existing commercial grade short-circuit analysis solvers based on sequence networks can be utilized for performing unbalanced distribution systems

Implementation of three-phase transformer model in radial load-flow analysis

This paper presents an efficient approach for developing three-phase transformer admittance matrices in the radial power-flow analysis. The proposed transformer model overcomes the singularity problem of the nodal admittance submatrices of ungrounded transformer configurations. This has been achieved by applying symmetrical components modeling. The classical (6 × 6) transformer nodal admittance matrix written in phase components is converted to sequence components instead of the (3 × 3) admittance submatrices. In this model, the phase shifts accompanied with special transformer connections are included in the radial power-flow solution process without any convergence problems. The final model of the transformer is represented by a generalized power-flow equation written in phase components. The developed equation is applicable for all transformer connections. The transformer model is integrated into the radial power-flow and tested using the IEEE radial feeders. The results have shown that the developed transformer model is very efficient and the radial power-flow has robust convergence characteristics

Power Quality Issues and Mitigation for Electric Grids with Wind Power Penetration

Large penetration of wind energy systems into electric-grids results in many power quality problems. This paper presents a classification of power quality issues, namely harmonics and short-duration voltage variation observed due to the integration of wind power. Additionally, different techniques and technologies to mitigate the effect of such issues are discussed. The paper highlights the current trends and future scopes in the improvement of the interconnection of wind energy conversion systems (WECSs) into the grid. As the voltage variation is the most severe power quality issue, case studies have been presented to investigate this problem using steady-state time-series simulations. The standard IEEE test system namely IEEE 123-node test feeder and IEEE 30-node grid are solved under different operating conditions with wind power penetration. Typical daily load profiles of a substation in Riyadh, Saudi Arabia, and an intermittent wind power generation profile are used in all case studies. Mitigation of voltage variations due to wind intermittency is achieved using reactive power compensation of the interface inverter. The results show the effectiveness of these approaches to avoid voltage variation and excessive tap setting movements of regulators and keep the voltage within the desired operating conditions

Application of Superconducting Magnetic Energy Storage (SMES) for Voltage Sag/Swell Supression in Distribution System with Wind Power Penetration

5 halama

Revised sequence components power system models for unbalanced power system studies

The objective of this paper is to present a revised sequence decoupled power system models for analyzing unbalanced power systems based on symmetrical networks. In these models, the three sequence networks are fully decoupled with a three-phase coordinates features such as transformer phase shifts and transmission line coupling. The proposed models have been utilized to develop unbalanced power-flow program for analyzing both balanced and unbalanced networks. The power flow solution is identical to results obtained from a full phase coordinate three-phase power-flow program

Application of parallel processing in fast decoupled load flow analysis

This paper discusses performance improvements achieved in fast-decoupled load flow solution through the use of parallel processing techniques. The fast- decoupled load flow formulation consists of two decoupled system models that can be solved simultaneously using two- core processors. The IEEE 30, 57, 118, 300 and 664 bus are used to evaluate the proposed program performance using parallel processing based on multi-core processors computer. The result shows that the parallel processing produces speedup for all cases. The performance and speedup of load flow solution by using two processors is near twice for all parallel part of the test systems. The result have followed the Amdal’s law speedup equation

Analysis of three phase distribution networks with distributed generation

This paper presents three phase Distributed Generations (DGs) model in unbalanced three-phase distribution power-flow and analyzes their effect when they are connected in distribution networks. The DGs can be modeled as a voltage-controlled node (PV node) or as a complex power injection (PQ node). The unbalanced threephase distribution power-flow has been developed on the basis of the symmetrical components. Newton Raphson method has been chosen for well known excellent convergence characteristics. The three-phase power-flow program has been tested using a practical 37 node distribution feeder. The solution of the base case of the 37 node feeder is compared with the radial distribution analysis package (RDAP). Then the three-phase power-flow method is used to analyze distribution networks with DGs. The analysis is carried out with various size, quantity and location of DGs. The simulation results show that the integration of DG into an existing distribution network can improve the voltage profile as well as reduces the total system losses