scholarly journals Development of mechanical coupling and exciter system in synchronous generators

2021 ◽  
Vol 6 (8 (114)) ◽  
Author(s):  
Raad Lafta Damij
Keyword(s):  
Renewable Energy ◽  
High Speed ◽  
Fossil Fuels ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Circuit Breaker ◽  
System Stability ◽  
Synchronous Generators ◽  
Excitation System ◽  
Mechanical Coupling

Power is generated in a variety of ways, including renewable energy, nuclear power, and burning of fossil fuels. The majority of our power is currently generated by burning fossil fuels, mostly natural gas and coal, to spin turbines attached to an electromagnetic generator. The main advantage of AC generation is that the voltage levels can be altered up and down with transformers, allowing electricity to be sent across long distances to the loads that demand it. The excitation system demand for large synchronous generators with a few hundred-megawatt ratings becomes very enormous. The challenge of transmitting such a big amount of power through high-speed sliding contacts becomes daunting. Mechanical coupling with exciter for synchronous generators is essential to mitigate such problems as the corrected output is linked directly to the field winding. This paper aims to develop a simulation of a 3-phase diesel engine-based 2 MVA/400 V synchronous generator with mechanical coupling and an exciter system. The developed simulation of the synchronous machine is set to deliver 25 % of its rating value (500 kW) till the time of 3 sec. Then, additional power of 1 MW is switched at t=3 sec via a 3-phase circuit breaker. The dynamic response of field current and field voltage of the simulation shows reasonable step performance as the steady-state time is less than 3 sec. The control of the excitation system allows the generator to maintain voltage, control reactive power flow, and assist in maintaining power system stability. The simulation was accurate when measuring the voltage and current under these changes. This analysis can help to investigate further integration with renewable energy sources.

scholarly journals Voltage Stability of Power Systems with Renewable-Energy Inverter-Based Generators: A Review

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 115
Author(s):  
Nasser Hosseinzadeh ◽  
Asma Aziz ◽  
Apel Mahmud ◽  
Ameen Gargoom ◽  
Mahbub Rabbani
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Voltage Stability ◽  
Reactive Power ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
System Stability ◽  
Special Issue ◽  
Synchronous Generators

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.

scholarly journals Hysteresis Controlled Based Power Quality Improvement in a Renewable Energy Source Connected to Utility grid with BESS Based STATCOM

2021 ◽  
Vol 7 (03) ◽  
pp. 250-255
Keyword(s):  
Renewable Energy ◽  
Digital Signal Processor ◽  
Distribution System ◽  
Distribution Systems ◽  
Fossil Fuels ◽  
Reactive Power ◽  
Neutral Current ◽  
Renewable Energy Sources ◽  
Power Converter ◽  
Energy Sources

This Paper presents a control strategy of the grid interconnected inverter Renewable Energy Sources (RES). This system can achieve the maximum benefits from these grid interconnected inverter when installed in 3-phase 4-wire distribution system. Increasing electrification of daily life causes growing electricity consumption and the rising number of sensitive or critical loads demand for high quality electricity. One of the main problems facing today is that related with the transmission and distribution of electricity. Due to the rapid increase in global energy consumption and the diminishing of fossil fuels, the customer demand for new generation capacities and efficient energy production, delivery and utilization keeps rising. Utilizing distributed generation, renewable energy and energy storage can potentially solve problems as energy shortage. With the increase in load demand, the Renewable Energy Sources (RES) are increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. The inverter can perform as a multi function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.

scholarly journals Post COVID-19 Recovery and 2050 Climate Change Targets: Changing the Emphasis from Promotion of Renewables to Mandated Curtailment of Fossil Fuels in the EU Policies

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1347
Author(s):  
Kyriakos Maniatis ◽  
David Chiaramonti ◽  
Eric van den Heuvel
Keyword(s):  
Climate Change ◽  
European Union ◽  
Renewable Energy ◽  
Global Economy ◽  
Fossil Fuels ◽  
Global Climate ◽  
Renewable Energy Sources ◽  
Climate Change Policy ◽  
Climate Impacts ◽  
The European Union

The present work considers the dramatic changes the COVID-19 pandemic has brought to the global economy, with particular emphasis on energy. Focusing on the European Union, the article discusses the opportunities policy makers can implement to reduce the climate impacts and achieve the Paris Agreement 2050 targets. The analysis specifically looks at the fossil fuels industry and the future of the fossil sector post COVID-19 pandemic. The analysis first revises the fossil fuel sector, and then considers the need for a shift of the global climate change policy from promoting the deployment of renewable energy sources to curtailing the use of fossil fuels. This will be a change to the current global approach, from a relative passive one to a strategically dynamic and proactive one. Such a curtailment should be based on actual volumes of fossil fuels used and not on percentages. Finally, conclusions are preliminary applied to the European Union policies for net zero by 2050 based on a two-fold strategy: continuing and reinforcing the implementation of the Renewable Energy Directive to 2035, while adopting a new directive for fixed and over time increasing curtailment of fossils as of 2025 until 2050.

Operation and control of a stand-alone power system with integrated multiple renewable energy sources

2021 ◽  
pp. 0309524X2110241
Author(s):  
Nindra Sekhar ◽  
Natarajan Kumaresan
Keyword(s):  
Renewable Energy ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Solar Pv ◽  
Power Requirement ◽  
Squirrel Cage ◽  
Hysteresis Controller ◽  
Squirrel Cage Induction Generator ◽  
And Control

To overcome the difficulties of extending the main power grid to isolated locations, this paper proposes the local installation of a combination of three renewable energy sources, namely, a wind driven DFIG, a solar PV unit, a biogas driven squirrel-cage induction generator (SCIG), and an energy storage battery system. In this configuration one bi-directional SPWM inverter at the rotor side of the DFIG controls the voltage and frequency, to maintain them constant on its stator side, which feeds the load. The PV-battery also supplies the load, through another inverter and a hysteresis controller. Appropriately adding a capacitor bank and a DSTATCOM has also been considered, to share the reactive power requirement of the system. Performance of various modes of operation of this coordinated scheme has been studied through simulation. All the results and relevant waveforms are presented and discussed to validate the successful working of the proposed system.

Analysing integration issues of the microgrid system with utility grid network

2021 ◽  
Vol 22 (1) ◽  
pp. 113-127
Author(s):  
Mulualem Tesfaye ◽  
Baseem Khan ◽  
Om Prakash Mahela ◽  
Hassan Haes Alhelou ◽  
Neeraj Gupta ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Distribution System ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Control Mode ◽  
Voltage Source ◽  
Modulation Scheme ◽  
Main Challenge ◽  
Utility Grid

Abstract Generation of renewable energy sources and their interfacing to the main system has turn out to be most fascinating challenge. Renewable energy generation requires stable and reliable incorporation of energy to the low or medium voltage networks. This paper presents the microgrid modeling as an alternative and feasible power supply for Institute of Technology, Hawassa University, Ethiopia. This microgrid consists of a 60 kW photo voltaic (PV) and a 20 kW wind turbine (WT) system; that is linked to the electrical distribution system of the campus by a 3-phase pulse width modulation scheme based voltage source inverters (VSI) and supplying power to the university buildings. The main challenge in this work is related to the interconnection of microgrid with utility grid, using 3-phase VSI controller. The PV and WT of the microgrid are controlled in active and reactive power (PQ) control mode during grid connected operation and in voltage/frequency (V/F) control mode, when the microgrid is switched to the stand-alone operation. To demonstrate the feasibility of proposed microgrid model, MATLAB/Simulink software has been employed. The performance of fully functioning microgrid is analyzed and simulated for a number of operating conditions. Simulation results supported the usefulness of developed microgrid in both mode of operation.

Nigeria: Advancing the Cause of Renewable Energy in Nigeria’s Power Sector Through its Legal Framework

2021 ◽  
Vol 50 (4-5) ◽  
pp. 433-444
Author(s):  
Olusola Joshua Olujobi ◽  
Temilola Olusola-Olujobi
Keyword(s):  
Renewable Energy ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Legal Framework ◽  
Comparative Approach ◽  
Energy Sources ◽  
Power Sector ◽  
Alternative Source ◽  
Regulatory Policies ◽  
Oil Sector

Fossil fuels have been the mainstream of energy supply and a major source of foreign exchange earnings for the Federal Government of Nigeria, in spite of being an unrenewable and unsustainable source of energy. Nigeria is yet to tap into the full benefits after privatising its power sector, including the new global evolution in the energy sector and the resulting increasing demand for renewable energy sources, which some consider to be cheaper and more environmentally friendly than fossil fuels and their allied products. Energy security is a challenge to socio-economic development in Nigeria, due to the country’s over-dependency on fossil fuels. In terms of their impact and the potentials to preserve energy sources for longevity and sustainability, however, fossil fuels will come to be seen as an out-dated alternative in the power sector as the energy industry evolves. The implications for Nigeria’s oil sector will not be limited to dwindling crude oil prices. The concerns include poor energy utilisation in Nigeria and the need to promote energy efficiency and sustainability. They have led to the formulation of new energy policies around the world to serve as a vehicle for translating solutions into reality. This study has adopted a library-based legal research method with a comparative approach. The study reveals that it is the lack of a coherent legal framework with incentives for using renewable energy that is largely seen as the key issue causing slow uptake of renewable energy as an alternative source of energy in Nigeria. As well as the need for a coherent legal framework on energy and incentives for using renewable energy sources, the study advocates stringent enforcement of existing energy regulatory policies.

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