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Short-Term Load Forecasting (STLF) has been a relevant research topic for over two decades now. However, it is an ongoing process since the behavior of consumers and producers continue changing as new technologies and new policies become available. This paper presents the results of a research study for the Spanish Transport System Operator (REE) with the objective of improving the forecasting accuracy...
The transition of the European electrical energy system leads to rising installations of renewable energy sources (RES). Average transmission distances and active and reactive power losses increase, because RES are mainly installed at sites with a high yield of primary energy. This development affects the voltage stability of the system. To address these challenges, a meshed high voltage direct current...
Differential line protection has been playing a major role in power transmission line protection due to its simplicity, operation speed, and high sensitivity. However, problems with communication channel make current comparisons difficult to achieve. To improve the insensibility to this problem, this paper proposes a new approach. First, the three currents are acquired. Then these currents are transmitted...
Distributed Energy Resources (DER) has been widely introduced in distribution networks in response to the increase of environmental awareness of the consumers. The benefits with the use of DER are increased with network reconfiguration, but in some countries exists the impossibility of island operation as well as the obligation to buy all the electricity generated. These limitations, in a network...
A mathematical analysis is developed in this paper to estimate the value of short-circuit currents in HVdc links. The study allows to calculate the evolution of the fault currents, their maximum values and the time they are reached. Thus, it can help to select adequate protection systems for HVdc grids. The mathematical study is verified by means of PSCAD simulations where the theoretical and simulated...
IEC TC77/SC77A/WG2 is poised to consider maintenance and revisions to IEC Standard 61000-4-15. Based on the results of multiple CIGRE Working Groups and literature publications, it appears that discrepancies between measured short-term flicker severity values and user complaints can be reduced by making modifications to the so-called Block 5 processing algorithm. For such modifications to be fairly...
Bulk power transmission across long distances has been mostly based in High Voltage Alternated Current solutions, not only due to their flexibility and cost, but also driven by the broad available portfolio. However, this solution has known physical boundaries which are quite relevant especially under the analysis of long-distance offshore wind farm applications. The aim of this paper is to present...
Because the use of 60-W incandescent lamps is declining in parts of the world, voltage fluctuations' effects on other devices may need to be explicitly considered in international standards. The existence of international standards for measuring interharmonics and the mathematical relationship with periodic amplitude modulation has suggested interharmonics as a potential basis for broadly characterizing...
The central objective of this paper is to investigate the harmonic behavior of 110-kV overhead lines. For this purpose, a method to describe the frequency-dependent series impedance and shunt admittance per unit length has been developed using the symmetrical components. The developed method uses input data that has been generated using the simulation software PSCAD. This paper begins by presenting...
Voltage stability assessment methodology based on construction of equivalent reactive power reserve utilizing limited access to observables is described in the paper. The purpose of the method is to be able to evaluate voltage stability margin in an on-line manner without the need to perform voltage stability analysis every time a contingency occurs in the power system. It is shown that by using reactive...
The electrical power supply structure of today's power systems is changing towards high shares of renewable power supply. This leads to a decreased number of conventional power plants. However, conventional power plants still play a major role when it comes to voltage and frequency control. Thus, the remaining power plants in the system together with the renewable power supply units have to carry...
The precise knowledge of fault locations is very important as longer period interruption caused by faults are responsible for most of the customer minute losses in the distribution grid. The objective of this paper is to locate different types of faults in a distribution grid by extracting the features of three phase fault currents employing wavelet transform (WT) and feeding the statistical measures...
The paper presents a comprehensive approach using clustering based data mining for load curves characterization in real distribution networks. The load curves characterized by their main indicators is made using information provided by Smart Meters. The proposed method was tested using a real database with 60 rural substations. The results demonstrate the ability of the methodology to be efficiently...
The paper is concerned with the analysis of the overhead transmission lines failures statistics as well as the analysis of the seasonal change in the failure intensity. The developed three-winding transformers models designed for the electrical networks structural reliability calculation are presented.
The paper addresses the problem of distributed generation efficiency improvement in terms of its parallel operation with unified power network. The optimization is carried out for a set of criteria, including distribution network voltage levels, transmission lines current-carrying limits, distributed generation maximum capacity etc. The objective function was formulated as mixed-integer programming...
The transition of the power grid with fewer reactive power sources demands new solutions to locally compensate reactive power in order to reduce transmission losses in the extra high voltage grid. The capability of high voltage clusters to meet these requirements is evaluated in this paper taking different approaches into account. The feasible contribution of distributed energy resources to provide...
Internal distribution systems such as photovoltaic parks allow to use DC or AC with a frequency different from 50Hz. In this paper is instead proposed to use more than one frequency at the same time. The grid voltage amplitude at the fundamental frequency can be increased while the voltage peak value is kept constant by adding odd harmonics to the voltage waveform. The currents are decreased for the...
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