High penetration of renewable energy sources (RES) leads to new challenges for protection devices. Protection schemes are typically designed according to the dynamic behavior of rotating machines as generation sources, while the RES dynamic response, mainly governed by inverters, is not considered. Consequently, some relevant algorithms of transmission line protection are experiencing challenges because of the fact that magnitude and phase angle comparison, amount of negative-sequence, and short-circuit current level are affected by the RES. Therefore, an in-depth study of this issue is necessary, one which considers the main causes and new methodological criteria solutions. This work presents an extensive literature review of the evaluation of electrical protection performance and the effects of RES connected to a power grid through inverters. Bibliographic data on many representative publications related to this topic are obtained to show the current research lines and their proposed solutions. In addition, this work identifies the main protection functions affected and describes the new protection schemes that consider RES. Finally, an analysis and discussion of the selected bibliography are presented.
Electrification of Peru's rural areas is an issue of vital importance for economic growth. However, these areas still have poor quality electricity service or operate in a stand-alone mode with high cost of energy. To address this problem, one of the most promising strategies proposes the use of renewable energy technologies through the implementation of microgrids. In this context, this research develops the analysis of 37 cases of rural villages throughout Peru in order to obtain the optimal microgrid design and the most feasible areas for its implementation, considering the associated costs, geographic location, and load characteristics. For this purpose, an optimization process is carried out using Homer Pro software with the aim of sizing the microgrid with the minimum net present cost and cost of energy. Then, an iterative process is developed in Matlab software to map cost values, renewable contribution, emissions, the energy charge and the annual savings in the utility bill. This analysis considers five scenarios base on a grid-connected microgrid (with sensitivity values of grid sellback price) and an off-grid microgrid system. The results show the geographic distribution of all the annual utility saving bill. For the grid-connected microgrid condition, it presents a profit
The ongoing transformation of electrical power systems highlights the weaknesses of the protection schemes of traditional devices because they are designed and configured according to traditional characteristics of the system. Therefore, this work proposes a new methodology to study the fault-generated high frequency transient signals in transmission lines through multiresolution analysis. The high frequency components are determined by a new digital filtering technique based on mathematical morphology theory and a spectral energy index. Consequently, wide spectra of signals in the time–frequency domain are obtained. The performance of this method is verified on an electrical power system modeled in ATP-Draw, where simulation and test signals are developed for different locations, fault resistances, inception angles, high frequency noises, sampling frequencies, types of faults, and shapes of the structuring element. The results show the characteristics of the fault such as the traveling wave frequency, location, and starting time.
Due to the impacts of climate change, one of the most promising strategies is to promote the intelligent use of technology based on renewable energy sources. One such strategy is the development of small-scale electrical systems, known as microgrids, which have the capability to utilize these clean energy sources. This paper analyzes 37 case studies from remote locations in Peru to determine the optimal design of microgrids (MG) and their environmental impact, while taking into consideration associated costs, geographic location, and demand characteristics. To achieve this goal, an optimization process is carried out using the HOMER Pro software, which aims to size the microgrid to the minimum net present value. This analysis considers five scenarios:demand connected only to the grid, MG connected to the grid without energy sale price, MG connected to the grid with energy sale price, isolated MG system, and isolated demand with a diesel generator. Subsequently, a calculation process is conducted using MATLAB software to map, calculate, and compare the emissions of each case.
Electrification of Peru's rural areas is an issue of vital importance for economic growth. However, these areas still have poor quality electricity service or operate in a stand-alone mode with high cost of energy. To address this problem, one of the most promising strategies proposes the use of renewable energy technologies through the implementation of microgrids. In this context, this research develops the analysis of 37 cases of rural villages throughout Peru in order to obtain the optimal microgrid design and the most feasible areas for its implementation, considering the associated costs, geographic location, and load characteristics. For this purpose, an optimization process is carried out using Homer Pro software with the aim of sizing the microgrid with the minimum net present cost and cost of energy. Then, an iterative process is developed in Matlab software to map cost values, renewable contribution, emissions, the energy charge and the annual savings in the utility bill. This analysis considers five scenarios base on a grid-connected microgrid (with sensitivity values of grid sellback price) and an off-grid microgrid system. The results show the geographic distribution of all the annual utility saving bill. For the grid-connected microgrid condition, it presents a profit in the range of $107.08 to $368.2 compared to loads connected to the grid; while, for the off-grid microgrid condition, it presents a profit in the range of $1269 to $4976 in comparison with loads connected to a diesel generator.
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