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This paper investigates the suitability of assessment methods for cascading outages for real-time assessment. A total of ten assessment methods for cascading outages are investigated, and for all of the investigated methods a complexity assessment is performed to assess the suitability of the method to real-time assessment. The investigation revealed that two of the methods are of special interest...
Numerical simulation is an essential tool to study and design HVDC grids interconnected with AC networks. Detailed real-time simulation of such complex power systems requires large computational resources. The connection of remote laboratories provides the possibility to share available resources thus meeting these demanding computational requirements. This concept is referred to as geographically...
This paper presents a phasor type model of variable speed wind turbine with Permanent Magnet Synchronous Generator (PMSG) for dynamic simulation study on Matlab/Simulink. Aim of the phasor model is to diminish the complexity and simulation time of the analysis of grid connected wind farm. The proposed phasor type model can be used as aggregated and individual model representations for the wind generators...
With rapidly increasing complexity of power grids in Europe, North America and Asia, liberalization of electricity markets and increasing penetration of renewable energy, the risk of large-scale emergencies and blackouts increases. This paper proposes a novel approach for development of software for modelling of decentralized intelligent systems for security monitoring and control in power systems...
In the context of the EU FP7 AMBASSADOR project, a simulation platform has been developed, as a support for the development and the deployment of energy management systems at the district level. Such simulation platform is called District Simulation Platform (DSP), and includes both the models of the physical components from the district, and the models of the energy management algorithms. The DSP...
In order to have a reliable and secure power system, frequency stability should be guaranteed. Primary Frequency Response (PFR) is used to arrest the frequency deviation upon a contingency. The significant penetration of wind generation in power grids has negative effect on the PFR, as the contribution of wind machines to the total system inertia is low and classical wind turbines do not have PFR...
Online voltage instability monitoring based on estimation of the Thevenin impedance has been thoroughly studied in many works. This equivalent impedance can be approximated either by phasor measurements of the load voltage and current or by these measurements in combination with system topology. Both approaches have their own characteristics, which are closely examined in this paper. The study is...
Increased penetration of variable resources mainly in the form of wind and PV plants creates new challenges to power system operation, in the form of increased thermal unit cycling, ramping requirements and increased capacity reserve requirements. One approach is to address these issues by utilizing the increased flexibility offered by energy storage devices (utility and customer owned), distributed...
This paper propose a test grid for investigation of slow coherency concept in nowadays active distributions power systems with small scale hydro units. The slow coherency concept is studied by increasing the model complexity of the small scale hydro generators. The purpose is to obtain a small signal equivalent suitable for the studies of the main bulk transmission system.
Training power system operators for situations with a high penetration of renewable energy sources (RES) is a prospective task of most system operator entities. The objective of this paper is to develop simplified but accurate models of variable speed wind turbine generation (WTG) which are implementable into a real-time training simulator (RTS) environment for a realistic operational training. The...
Prediction of the potential threats due to direct lightning strokes of sensitive targets, e.g., overhead power-line towers, substations or buildings, requires accurate modeling of the transient impedance of grounding systems. When large-scale simulations are needed, detailed and computationally intensive models are hardly viable, although they usually offer great accuracies. In this work we investigate...
Transient stability of doubly-fed induction machine (DFIM) in hydro pumped storage plant (PSP) is analyzed and compared with synchronous machine in this paper. Model of turbine governor and model of converter control of DFIM are presented as they are applied in computer software for dynamic analyses of electric-power system. The principle of frequency control—i.e., permanent droop—and control of network...
In this paper an algorithm for the solution of the European electricity market coupling is presented, considering all block and complex orders available in the European Power Exchanges. The model takes into account the clearing conditions of profile and regular block orders, linked block orders, exclusive group of block orders and flexible hourly orders, as well as the clearing conditions of Minimum...
We test the stochastic dual dynamic programming (SDDP) approach on a system an order of magnitude larger than previously published studies. The analysis shows that the SDDP-approach can be applied to very large system sizes to solve the hydropower scheduling problem through formal optimisation and obtain individual decision variables for every reservoir. However, this can be very time-consuming compared...
A formulation is proposed in which an AC-DC system is modeled as a combination of AC grids, DC grids, injectors, AC two-ports and AC/DC converters, respectively. This modular modelling facilitates the dynamic simulation of future complex AC/DC systems. Furthermore, it can be exploited by the solver, which performs less operations on components with lower dynamic activity, and offers parallel processing...
Long-term simulations of electric power systems are an essential tool for power system planning and operation. As power systems are extraordinarily complex, simplifying assumption have to be made to find computational tractable model formulations. In this paper we define aggregation methods 1) for simulation time, 2) for generation units and 3) for load demand units. The performance of the aggregation...
Owing to the massive deployment of renewable power production units over the last couple of decades, the use of stochastic optimization methods to solve the unit commitment problem has gained increasing attention. Solving stochastic unit commitment problems in large-scale power systems requires high computational power, as stochastic models are dramatically more complex than their deterministic counterparts...
A centralized approach to solve optimal operation of a practical sized distribution grid with a large number of electric vehicles (EVs) is a computationally challenging task. This work proposes a bi-level hierarchical optimization framework to solve the problem. In the hierarchy, optimal operation of the distribution grid is considered in one level, while the optimal operation of EVs is carried out...
This paper presents an approach to dispatch taps of Load Tap Changing (LTC) transformers, switched capacitors and Plug-in Electric Vehicle (PEV) charging in distribution feeders to minimize feeder daily peak demand, using a nonparametric Bootstrap technique, an alternative to Monte Carlo Simulations (MCS), to account for the PEV charging temporal uncertainties. From an initial sample of independent...
It poses high requirements for the calculation speed and the precision of the solving method when we consider the large-scale transmission expansion planning (TEP) problems. Therefore, combined with the respective characteristics of EDA (Distribution of Estimation Algorithm) and DE (Differential Evolution algorithm), this paper puts forward a new hybrid EDA/DE algorithm for large-scale TEP problems...
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