Increasing Penetration Of Wind Energy Research Articles

Wind Energy Supply Profiling and Offshore Potential in South Africa

South Africa’s energy network is under severe pressure due to low supply and overwhelming demand. With an increase in renewable energy providers, specifically wind energy, knowing how the supply can satisfy the electricity demand may relieve apprehensions. This research aims to provide insight into the wind energy supply of South Africa and question how well this supply meets the demand of South Africa. The methodology used in this work highlights the importance of access to public datasets to dispel misconceptions in the energy industry. Additionally, the work supports network planning and the arguments for increasing wind energy penetration on the South African grid. Wind profiles and the typical energy production of South African wind farms are compared to electricity demand. The geographical spacing of the operational wind farms is considered. It is observed that wind energy supply assists in the peak electricity hourly demand as well as seasonal peaks. Furthermore, South Africa’s coast is analysed to determine the offshore wind power potential, where shallow and deep waters are considered. It is observed that South Africa has a high potential for offshore wind, even after losses are applied.

Assessment of power quality in the utility grid integrated with wind energy generation

The ever increasing wind energy penetration into the utility grid causes challenges in the power quality (PQ) of the electrical supply. Therefore, this work proposed PQ assessment in the utility grid which is interfaced with the wind energy generation using Stockwell's transform (ST) under various operating events. The experimental set-up for assessing the PQ included an emulated wind generator synchronised with the utility grid at the point of common coupling. The current and voltage measurements are carried out using PQ analyser associated with WTViewer application software. The recorded signals of the voltage waveforms are assessed using ST to detect the various PQ issues related to the grid integration and wind generator's outage. To investigate the effects of various types of loads on the PQ, the same events are carried out. Various PQ disturbances are successfully detected using the proposed algorithm. Performance of the proposed algorithm is also tested on the grid integrated solar photovoltaic (PV) system to investigate and compare the PQ disturbances associated with the grid integrated solar PV system.

Impacts of Wind Energy Integration to the Utility Grid and Grid Codes: A Review

Background: This paper reviews the requirements imposed by Transmission System Operators (TSOs) in their grid codes to address intolerable implications of integrating large Wind Power Plants (WPPs) to the grid. Besides the common objectives, terminologies used by different TSOs were distinct. Therefore, developing a harmonized grid code is imperative. Introduction: On the recommendation of the European Commission, European Network of Transmission System Operators for Electricity (ENTSO-E) has made concerted efforts in the direction of developing a harmonized grid code, and published its document in March 2013. Method: Several TSOs have updated their grid codes in accordance with the increasing wind energy penetration. We have made an effort to present a comparison between different integration requirements specified by different grid codes. The outcomes presented will certainly be beneficial to the countries, which are in the process of enacting their own grid code. Result: We have reviewed different grid codes in terms of Low Voltage Ride-Through (LVRT) requirement, operating voltage and frequency range, active power control (frequency regulation) and reactive power support (voltage regulation). Conclusion: The present study envisages helping wind turbine manufacturers and WPP developers, as it would provide them a clear insight into the regulations imposed on WPPs as included/ updated in different grid codes.

Voltage stability assessment and enhancement of power grid with increasing wind energy penetration

This paper presents the voltage stability assessment of power system with increasing wind energy penetration. The effects of increasing Doubly-Fed Induction Generator-based Wind Energy Conversion System (DFIG-WECS) penetration in the power system have been investigated in this work. Active Power-Voltage (PV) analysis was employed to determine the voltage stability limits in terms of the maximum loadability limit within which stable operation of the grid can be guaranteed as the wind energy penetration increases. The analyses in this work were carried out both for normal and contingency operations of the grid. IEEE 14-bus test system was used as the study case. Simulations were carried out using DigSilent PowerFactory software and results analyses were done using MATLAB. Furthermore, the effects of integrating DFIG-WECS on the loading of essential power system equipment are investigated. The results show that the maximum loadability limit of the study system increases with increasing DFIG-WECS power penetration up to 100%. However, the overloading effects on critical transmission lines presents a definitive limit to the allowable practical penetration level, which is determined to be 28.06%. This limit can be improved to 29.88%, 46.3% and 52.23% by Thyristor-Controlled Series Capacitor (TCSC) application on Line 9–14, upgrading Line 9–14 to double circuit, and upgrading both Line 9–14 and Line 13–14 to double circuit respectively. Thus, effective line enhancement and reactive power compensation strategy such as those offered by FACTS devices are required for a voltage-stable operation of the grid with increasing wind energy penetration.

An Energy Function-Based Optimal Control Strategy for Output Stabilization of Integrated DFIG-Flywheel Energy Storage System

This paper presents an energy function-based optimal control strategy for output stabilization of integrated doubly fed induction generator (DFIG)-flywheel energy storage architecture to keep the grid power isolated from wind power output and voltage fluctuations and thus enabling increased penetration of wind energy resources. First, a grid connected two mass DFIG and a grid supportive single mass squirrel cage induction generator-based flywheel energy storage system model have been considered for controller design and proof of concept exploration. Second, a new energy function-based control architecture is proposed for maximum energy transfer from wind farm during normal operation and to improve DFIG low voltage ride through characteristics. It has been observed that the proposed architecture is very effective in mitigating oscillations and thus increasing wind energy penetration.

An Integrated Dynamic Modeling and Adaptive Controller Approach for Flywheel Augmented DFIG Based Wind System

This paper presents an integrated Doubly Fed Induction Generator (DFIG) and flywheel energy storage architecture that provide output power stability based on a new dynamic adaptive control approach. First, a grid-connected two-mass DFIG and a grid-supportive single-mass squirrel cage induction generator based flywheel energy storage system models have been considered for controller design and proof of concept exploration. Second, new adaptive dynamic control architecture is designed for active and reactive power balancing from wind farm with flywheel energy storage during normal and abnormal operating conditions. The proposed architecture is very effective in mitigating oscillations, thus providing a novel methodology for a stable microgrid or increasing wind energy penetration to the grid.

Towards a flexible energy system – A case study for Inland Norway

This paper analyze the benefits of the use of bioenergy, solar thermal and wind energy in a flexible energy system to increase the share of renewable sources (RES) in primary energy supply, reduce primary energy consumption (PEC) and ensure power supply security in Inland Norway, and Norway at large. Firstly, the Inland reference energy system was built and validated using the EnergyPLAN system analysis tool based on the year 2009. Two alternative systems (scenarios), mainly of bio-heat and heat pumps in individual and district heating systems were then constructed and compared with the reference system using EnergyPLAN. The quality of a given energy system can be best described by its PEC, RES, emission levels and socio-economic costs. The result shows that it is plausible to improve the quality of the Inland energy system by optimal resource assortment in the energy mix. Integrated use of bio-heat and heat pumps in individual and district heating systems, as a replacement for direct electric heaters would reduce PEC and socio-economic costs considerably more than intensive bio-heating deployment alone, thereby increasing total domestic green electricity generation. The ability to integrate wind power and its value in the Inland energy system is more reflected by reducing imports of electricity during peak demand periods in winter, as wind power availability in the region is significant as opposed to the low precipitation during these periods. In addition, increasing wind energy penetration helps to limit biomass consumption in a district heating system built on heat pumps and bio-heat boilers.

Increasing Wind Energy Penetration Level by Using Pumped Hydro Storage in Island Micro-Grid System

Ramea is a small island in southern Newfoundland. Since 2004, it has a wind-diesel hybrid power system to provide power for approximately 600 inhabitants. In this paper, wind speed data, load data, and sizing of pumped hydro system at Ramea, Newfoundland are presented. The dynamic model of wind turbine, pumped hydro system, and diesel generator are included in this paper. The dynamic model is simulated in SIMULINK/MATLAB to determine the system voltage and frequency variation and also to visualize different power outputs. Sizing of pumped hydro system indicates that a 150-kW pumped hydro storage system can be installed in Ramea to increase the renewable energy fraction to 37% which will reduce non-renewable fuel consumption on this island. Also, it is found that a pumped hydro energy storage system for Ramea is a much better choice than a hydrogen energy storage system. Such a system will have a higher overall efficiency and could be maintained using local technical expertise, therefore, a more appropriate technology for Ramea.

Risk Quantification Associated With Wind Energy Intermittency in California

As compared to load demand, frequent wind energy intermittencies produce large short-term (sub 1-h to 3-h) deficits (and surpluses) in the energy supply. These intermittent deficits pose systemic and structural risks that will likely lead to energy deficits that have significant reliability implications for energy system operators and consumers. This work provides a toolset to help policy makers quantify these first-order risks. The thinking methodology/framework shows that increasing wind energy penetration significantly increases the risk of loss in California. In addition, the work presents holistic risk tables as a general innovation to help decision makers quickly grasp the full impact of risk.