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This paper models the impacts of Demand Response Programs (DRPs) on the behavior of energy market participants in the electricity markets in the presence of renewable energies. In such oligopolistic environment, market interactions are considered by using a game theoretic model, and the market transactions are cleared by means of a Security Constraint Unit Commitment program (SCUC). One sample is...
In the last decade, the level of variable renewable energy sources (RESs) integrated in distribution network systems have been continuously growing. This adds more uncertainty to the system, which also faces all traditional sources of uncertainty and those pertaining to other emerging technologies such as demand response and electric vehicles. As a result, distribution system operators are finding...
The growing trend of variable energy source integration in power systems (especially at a distribution level) is leading to an increased need for flexibility in all levels of the energy flows in such systems: the supply, the network and the demand sides. This paper focuses on a viable flexibility option that can be provided by means of a dynamic network reconfiguration (DNR), an automatic changing...
Integration of emerging energy resources in distribution level reveals new opportunities for decision makers to coordinate various energy vectors under the concept of multi-energy system (MES). In this paper, the behavior of a multi-energy player (MEP) who can trade more than one energy carrier to enhance operational flexibility of MES has been investigated. MEP participates in retail and wholesale...
This paper focuses on dynamic performance control of modular multilevel converters (MMC) in high-voltage direct current (HVDC) transmission systems. To achieve this objective, a new mathematical model including six state variables of ac-currents and dc-link voltage of MMC, and circulating currents of converter arms are proposed for MMC in d-q reference frame. In addition, a robust control technique...
A droop-Lyapunov based control technique using direct-quadrature (d-q) rotating frame dynamic model is presented in this paper for the frequency and voltage magnitude regulation of a stand-alone single-phase voltage-source inverter (SPVSI). Steady-state and dynamic performance of the controller are analyzed based on the d-q frame model and direct Lyapunov method respectively to satisfy control aims...
The adoption of electric vehicles (EVs) on a large scale can lead to significant social and economic benefits. The effort of promoting the use of EVs in road transportation is essential to meet the climate change targets and manage the ever unstable prices of perilously diminishing fossil fuels. On the other hand, there are still many uncertainties in the market regarding the acceptability of EVs...
With the advent of restructuring electricity sector and smart grids, combined with the increased variability and uncertainty associated with electricity market prices (EMP) signals and players' behavior, together with the growing integration of renewable energy sources, enhancing prediction tools are required for players and different regulators agents to face the non-stationarity and stochastic nature...
Renewable energies are in constant growth and evolution, being a clean way to provide the energy required for the sustainable development of human society. In this context, energy storage systems are a key factor in the integration of renewable generation, because through them, the flexibility of the power system can be increased. Lead-acid batteries have been extensively used to provide electricity...
This study aims to evaluate the implications of the use of maritime pine non-debarked wood chips as an alternative solid fuel in industrial boilers in Portugal, highlighting the energy properties and chemical composition of the ash produced. Several samples have been collected from different sources, on which an approximate analysis is carried out to determine the volatile matter content, fixed carbon...
Significant wind power ramps have a remarkable influence on the integration of wind power. Their variability and uncertainty affect to the wind power forecast increasing the error and reducing the reliability in the continued operation of the power system. Ramp events are considered the main source of forecasting error and their study is imperative for an improvement of prediction tools. In this aspect,...
The aim of this paper is to avoid overloading a private customer distribution transformer (DT) in a Portuguese insular area through the means of a new smart electric vehicle (EV) charging scheduler. Firstly, the consequence of the penetration of EVs on the dielectric oil deterioration of the DT of the industrial unit is estimated. The workplace allows the EVs to charge while their owners are working...
The aim of this paper is to present the development of an innovative experimental reflective pulse oximetry solution targeting wearable health system for daily monitoring purposes. The measurement of two common human physiological indicators is performed, which are the pulse rate and the blood oxygenation level (SpO2). The design options are detailed, covering photoplethysmographic (PPG) signals sensing...
Photoplethysmography (PPG) sensors are an inexpensive yet cost-effective way to track data correlated to the heart pulsation. The information is acquired with light signals generated by means of a photodiode and by detecting the amount of reflected or transmitted light through the tissue. In this paper, a novel methodology that enables a systematic approach for evaluating high compact signal processing...
Participation of consumers in Demand Response (DR) programs improves system stability and reliability as well as market efficiency. Retailers and distributors purchase DR to advance business and system reliability, respectively. Meanwhile, large consumers, Distribution System Operators (DSOs), Load Service Entities (LSEs), and DR aggregators sell DR to increase their own profits. In this context,...
Alongside significant advantages which come through large scale integration of wind power into the grid, it imposes some essential challenges on Independent System Operators (ISOs) performance. The stochastic nature of wind power causes technical and economic impacts on power system operation. As one of the highly-flexible and low-cost solutions, demand response (DR) resources are expected to be helpful...
This paper explores different modelling techniques for representing electrochemical energy storage devices in insular power grid applications. Particular attention is given to Thevenin based and not Thevenin based models. A case study involving two insular power systems with renewable generation are used to stand out the performance of the selected battery technologies: Lithium-ion (Li-ion), Nickel-Cadmium...
This paper analyses the impact of the penetration of electric vehicles (EVs) charging loads on thermal ageing of a distribution transformer of a private industrial client that allows EVs to charge while their owners are at work and at three different working shifts during a day. Furthermore, the system is part of an isolated electric grid in a Portuguese Island. In this paper, a transformer thermal...
This paper analyses the impact of the high penetration of electric vehicles (EVs) charging loads on the thermal ageing of distribution transformers of an isolated electric grid in a Portuguese Island. In this paper, a transformer thermal model is used to estimate the hot-spot temperature (θh) given the load ratio. Real data are used for the main inputs of the model, i.e. residential load, transformer...
The introduction of Variable Renewable Energy Sources (VRESs) such as wind to the future power portfolio can have significant effects on raising the daily net load variations and consequently may cause more operation costs as well as inefficient operation of units, and even in the worst case put the system's security at risk. On this basis, the need for a greater flexibility is essential to ensure...
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