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The integration of distributed renewable energy resources into active power distribution grids (Smart Grids) is an important activity nowadays. Advanced but also standardized remote control functions for such renewable sources are necessary to allow a higher penetration degree of them in power distribution grids. These functions are defined by the power utility automation approach IEC 61850 but their...
This paper proposes an optimal bidding strategy for a wind producer who participates as price-maker in the day-ahead electricity market. In order to empower the wind producer against the challenges introduced by the intermittent nature of wind power and improve his position into the market, demand response schemes are considered to be incorporated into his portfolio. The producer objective is the...
For the approximation of low-voltage grid dynamics we present an energy based bottom-up model to create highly diverse household load profiles. In an object-oriented approach, nodal loads are represented by classifications of appliances and distributed to the phases in order to consider the characteristically unbalanced load of residential customers over time. Probability parameters, regarding time...
In this paper an algorithm is developed for solving the Optimal Power Flow (OPF) and Security Constrained OPF (SCOPF) problem in mixed AC/DC grids. Non-linear models are used for power lines and AC/DC and DC/DC converters. The converter models include terminal losses and power rating constraints. The formulation of the SCOPF problem is such that it works for preventive OPF where no corrective actions...
This paper shows that the voltage stability margin of a power network can be determined through the application of a transformation that allows the decomposition of the grid into a set of decoupled source-line-load circuits. By monitoring a small number of these circuits one can analyze the behavior of the actual power system. Therefore it is not necessary to monitor the complete network, since by...
Due to the inevitable prediction errors and/or sudden ramping down, the high penetration of wind power in electricity markets entails significant challenges. In this paper, a new demand response (DR) design targeting the power deficit (mainly caused by wind power) in the real-time market is proposed. When a power deficit is expected in the short-term operation, in comparison to exaggerated spot prices,...
In this paper, we extend the application of direct methods, originally proposed for transient stability assessment, to the problem of mid-term stability analysis. By exploring the singular perturbation theory and direct methods, the stability analysis of an electrical power system is split into the stability analysis of two simplified subsystems: the fast and slow subsystems. As a result of this decomposition,...
The paper describes the co-simulation platform that integrates a mobility simulator adapted to represent e-mobility with a dynamic simulator of the power distribution network and with an UMTS communication network simulator. The platform appears useful in order to assess the effects of the transients caused by the concurrent charging of a large number of electric vehicles to the operating conditions...
The rapid spread of the Dispersed Generation (DG) in Distribution Networks (DNs) pushes the Distribution Company to actively manage and control the DN. In order to make this possible, a thorough knowledge of the system state is mandatory and the well-known state estimation techniques used by Transmission System Operators (TSOs) could be applied, but the DNs lack of redundancy due to very limited number...
This paper proposes a passive islanding detection technique for distributed generations in grid-connected microgrids and presents a comprehensive comparative analysis of intelligent classifiers for passive islanding detection application. The proposed method utilizes pattern recognition techniques in classification of underlying signatures of wide variety of system events on critical system parameters...
In this paper, a simplified formulation of the steady-state, distributed-parameter model of AC transmission lines is presented, which is sufficiently accurate in practice for very long lines. The simplification stems from a reduction in the number of parameters involved in the model and provides a better understanding of the effect that the remaining parameters have on the line performance (i.e.,...
This paper aims to describe methods to forecast wind speeds experienced around overhead lines (OHLs) in order to predict the wind cooling effect and thus the dynamic line ratings (DLRs) of OHLs. The wind speed at a particular OHL span is forecast through a kriging interpolation between the wind speed predictions produced by a vector auto-regressive (VAR) model for a limited number of weather stations...
This paper presents a new methodology to improve the frequency stability of power system with the large integration of distributed energy resources. Distributed energy resources don't contribute to the inertial response of the system as they are decoupled from the grid by the converters. The capability of the distributed energy resources especially (PV and Wind) to provide active power support in...
Double-circuit HVDC transmission lines on the same tower have becoming an inexorable trend for they can not only increase unit corridor area transmission ability but also reduce construction costs. After thoroughly study the phase-mode transformation method for double-circuit HVDC lines and considering that in practice they are not transposed, a novel algorithm for locating faults using mixed modulus...
The energy transition will bring large changes to residential load profiles. In order to assess whether the current low voltage (LV)-grids are capable of handling these changes, future scenario analysis must be used to assess the grid adequacy. To this end, an approach is proposed, incorporating scenario-based household load modelling, LV-feeder clustering and probabilistic load flow calculations...
The size and complexity of large power systems, such as the European one, often make them unmanageable for the purposes of Transmission Expansion Planning (TEP). Therefore, network reduction methods are necessary to condense their key features into a workable model, which should approximate the behavior of the nodal system as accurately as possible. We define critical branches as the transmission...
The integration of distributed generation causes an increase of the voltage magnitude in low voltage (LV) grids. In addition to classical grid expansion distribution system operators have various options at their hands to reduce the voltage rise, e.g. by installing distribution transformers with on-load tap changers or voltage regulators. But for efficient control the network operators need information...
In this study, we investigate two countermeasures using inverters of photovoltaic (PV) power generation systems to avoid short-term voltage instability caused by sudden shutoff of the PV systems after a voltage sag. One of the countermeasures is the operation of the PV system at a leading power factor in the normal state, and the other is the dynamic reactive power control after the fault. First,...
A smart grid is a fully automated electricity network, which monitors and controls all its physical environments of electricity infrastructure being able to supply energy in an efficient and reliable way. As the importance of cyber-physical system (CPS) security is growing, various intrusion detection algorithms to protect SCADA system and generation sector have been suggested, whereas there were...
In R&D projects as well as in development work, simulations of grid configurations and control methods are a common tool for assessing different technical options. At the same time, these simulations are often limited by difficulties in data exchange, simply due to the fact that systems are not compatible and data format in operational systems is not aligned with data in simulation and analysis...
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