scholarly journals Capacity Value from Wind and Solar Sources in Systems with Variable Dispatchable Capacity—An Application in the Brazilian Hydrothermal System

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3196
Author(s):  
Nilton Bispo Amado ◽  
Erick Del Bianco Pelegia ◽  
Ildo Luís Sauer
Keyword(s):  
Renewable Resources ◽  
Limited Capacity ◽  
Robust Methods ◽  
Load Curve ◽  
Electric System ◽  
Variable Capacity ◽  
Variable Generation ◽  
Combine Load ◽  
Hydroelectric Plants ◽  
Planning And Operation

The most robust methods to determine the capacity contribution from intermittent sources combine load curve, variable generation profile, and dispatchable generators’ data to calculate any new inserted variable source’s capacity value in the power system. However, these methods invariably adopt the premise that the system’s dispatchable generators’ capacity is constant. That is an unacceptable limitation when the energy mix has a large share of hydroelectric sources. Hydroelectric plants are dispatchable sources with variable maximum power output over time, varying mainly according to the reservoirs’ level. This article develops a method that makes it possible to calculate the capacity value from renewable resources when the dispatchable generation units of an electric system have variable capacity. The authors apply the method to calculate the capacity value from solar and wind sources in Brazil as an exercise. By abandoning the hypothesis of constant dispatchable capacity, the developed approach is in principle extensible for other energy-limited resources, such as batteries and concentrating solar power (CSP). This can be a strategy to incorporate energy-limited capacity sources into the planning and operation models as reliable capacity sources.

scholarly journals The Why of Adaptive Protections in Modern Electrical Networks

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Juan Martín Guardiola Montenegro ◽  
Eduardo Gómez Luna ◽  
Eduardo Marlés Sáenz ◽  
Jorge Armando De la Cruz Saavedra
Keyword(s):  
Renewable Energy ◽  
Distributed Generation ◽  
Renewable Resources ◽  
Harmonic Distortion ◽  
Distribution Networks ◽  
Electrical Networks ◽  
Dynamic Changes ◽  
Interconnected System ◽  
Electric System ◽  
Micro Grids

Electrical networks are evolving and taking on more challenges as the inclusion of renewable energy and distributed generation units increase, specially at distribution levels. Big trends of generating electricity with alternative and renewable resources has promoted the formation of distribution networks subsystems or micro grids, capable of supplying their own electric demand and to export energy to the interconnected system, if necessary. However, the effects of these generation units into the network and into the microgrid as well are many, as harmonic distortion, voltage flickers and especially in electrical protections.This paper provides an overview about implementation of renewable energy and distributed generation worldwide, as well as an introduction to microgrids concept and its main impacts and challenges into the electric systems. Finally, the main impacts of microgrid on protection equipments are presented at a distribution level, being adaptive protections one of the solutions to the dynamic changes of the electric system.

scholarly journals Classification of Special Days in Short-Term Load Forecasting: The Spanish Case Study

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1253 ◽  
Author(s):  
Miguel López ◽  
Carlos Sans ◽  
Sergio Valero ◽  
Carolina Senabre
Keyword(s):  
Load Forecasting ◽  
Short Term ◽  
Load Curve ◽  
Electric System ◽  
Forecasting Error ◽  
Social Events ◽  
Short Term Load Forecasting ◽  
Forecasting System

Short-Term Load Forecasting is a very relevant aspect in managing, operating or participating an electric system. From system operators to energy producers and retailers knowing the electric demand in advance with high accuracy is a key feature for their business. The load series of a given system presents highly repetitive daily, weekly and yearly patterns. However, other factors like temperature or social events cause abnormalities in this otherwise periodic behavior. In order to develop an effective load forecasting system, it is necessary to understand and model these abnormalities because, in many cases, the higher forecasting error typical of these special days is linked to the larger part of the losses related to load forecasting. This paper focuses on the effect that several types of special days have on the load curve and how important it is to model these behaviors in detail. The paper analyzes the Spanish national system and it uses linear regression to model the effect that social events like holidays or festive periods have on the load curve. The results presented in this paper show that a large classification of events is needed in order to accurately model all the events that may occur in a 7-year period.

Exploration of the integration of renewable resources into California's electric system using the Holistic Grid Resource Integration and Deployment (HiGRID) tool

Energy ◽  
2013 ◽  
Vol 50 ◽  
pp. 353-363 ◽  
Author(s):  
Joshua D. Eichman ◽  
Fabian Mueller ◽  
Brian Tarroja ◽  
Lori Smith Schell ◽  
Scott Samuelsen
Keyword(s):  
Renewable Resources ◽  
Resource Integration ◽  
Grid Resource ◽  
Electric System

scholarly journals The smoothing effect for renewable resources in an Afro-Eurasian power grid

2017 ◽  
Vol 14 ◽  
pp. 253-260 ◽  
Author(s):  
Maria Krutova ◽  
Alexander Kies ◽  
Bruno U. Schyska ◽  
Lueder von Bremen
Keyword(s):  
Power Systems ◽  
Renewable Resources ◽  
Power Transmission ◽  
Excess Energy ◽  
Weather Data ◽  
Smoothing Effect ◽  
Renewable Generation ◽  
Transmission Grid ◽  
Renewable Power ◽  
Variable Generation

Abstract. Renewable power systems have to cope with highly variable generation. Increasing the spatial extent of an interconnected power transmission grid smooths the feed-in by exchange of excess energy over long distances and therefore supports renewable power integration. In this work, we investigate and quantify the balancing potential of a supergrid covering Europe, Africa and Asia. We use ten years of historical weather data to model the interplay of renewable generation and consumption and show that a pan-continental Afro-Eurasian supergrid can smooth renewable generation to a large extent and reduce the need for backup energy by around 50 %. In addition, we show that results for different weather years vary by up to approximately 50 %.

scholarly journals Relevance and Applicability of Multi-objective Resource Constrained Project Scheduling Problem: Review Article

2011 ◽  
Vol 1 (6) ◽  
pp. 144-150
Author(s):  
B. O. Odedairo ◽  
V. Oladokun
Keyword(s):  
Renewable Resources ◽  
Project Scheduling ◽  
Scheduling Problem ◽  
Limited Capacity ◽  
Resource Constrained ◽  
Resource Constrained Project Scheduling ◽  
Multi Objective ◽  
Objective Performance ◽  
Project Scheduling Problem ◽  
Performance Dimension

Resource-Constrained Project Scheduling Problem (RCPSP) is a Non Polynomial (NP) - Hard optimization problem that considers how to assign activities to available resources in order to meet predefined objectives. The problem is usually characterized by precedence relationship between activities with limited capacity of renewable resources. In an environment where resources are limited, projects still have to be finished on time, within the approved budget and in accordance with the preset specifications. Inherently, these tend to make RCPSP, a multi-objective problem. However, it has been treated as a single objective problem with project makespan often recognized as the most relevant objective. As a result of not understanding the multi-objective dimension of some projects, where these objectives need to be simultaneously considered, distraction and conflict of interest have ultimately lead to abandoned or totally failed projects. The aim of this article is to holistically review the relevance and applicability of multi-objective performance dimension of RCPSP in an environment where optimal use of limited resources is important.

Seven-colour photometry at the Geneva Observatory

1966 ◽  
Vol 24 ◽  
pp. 262-266 ◽  
Author(s):  
M. Golay
Keyword(s):  
Wide Band ◽  
Electric System ◽  
Band Type

During the last 5 years, we have developed a seven-colour photometry at the Geneva Observatory. Our multicolour photo-electric system is of a wide-band type; the bandwidth being about 500Å for four filters. The three others are similar to theUBVsystem. In Table 1 we give the filter combinations used in our photometry (1).

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