94 research outputs found
A Practical Approach to Mitigate the Harmonic Distorsion in a Microgrid, Case Study
No full textThe actual study proposes a power quality analysis of a medium-sized industrial microgrid which in turn generates harmonic disturbances on the medium voltage side of a 110kV/20kV substation. Due to the interconnection of different loads on similar medium voltage busbars, the harmonic distortion propagates along the circuit affecting the stability of the local grid. Using advanced simulation tools based on numerical analysis an equivalent circuit of the microgrid is created. According to the computed results levels of total harmonic distortion exceeding the limit values imposed by the national performance standards were discovered within the load understudy. In this regard, a complex analysis procedure targeting the variable speed drives is deployed in order to identify the proper technical solutions for attenuation and filtering of harmonics in the system. Therefore, this study highlights solutions for mitigating the higher-order harmonics and the impact of their implementation, i.e. the best solution
Modelling and evaluation of the Baseline Energy Consumption and the Key Performance Indicators in Technical University of Cluj-Napoca buildings within a Demand Response programme: a case study
No full textDemand response (DR) programmes offer to customers the opportunity to reduce the power peak and the energy
consumption in response to a price signal or financial incentive. Typically, the request to reduce peak demands is made for a
specific time period on a specific day, which is referred to as a DR event. To predict a reference energy consumption level in
case of different buildings or blocks of buildings within the Technical University of Cluj-Napoca, this study proposes an artificial
intelligence enhanced energy profiling method and a more intuitive yet simple method for baseline determination, easy to
understand, which allows all the interested parties to estimate the energy and economy savings after a DR event. Once the
baseline electric load profile is established, the aim of this study is to calculate some predefined key performance indicators.
The two baseline detection methods are compared with each other as a measure of DR event effectiveness. The study has
been conducted to clearly demonstrate the economic and environmental benefits of controlling the aggregated load curve in
blocks of buildings within several effectively applied DR programmes
Estimation of an equivalent short solenoid model using different numerical methods
No full textThe paper deals with an inverse magnetostatic problem related to the reconstruction of a permanent magnet encapsulated inside the cathode of a magnetron sputtering device. The numerical analysis is aimed to obtain the estimation of a short solenoid equivalent to the unknown magnet. Least squares approach has been used to solve the functional defined as squared sum of the residuals. A comparison of the results obtained with Genetic Algorithm approach and nonlinear system of equations is performed. A regularized solution, which is in good agreement with the experimental data, was found by applying a Newton adapted regularization technique
Modeling and Forecasting Energy Demand in TUCN Buildings
No full textThe accurate difference between the actual and predicted value of the future load demand defines the load forecasting. Load forecasting provides the most important information for power delivery and planning and plays an important role in energy management system. The aim of this paper is to model the electric baseline load profile, based on the predefined Key Performance Indicators (KPIs), in case of TUCN (Technical University of Cluj-Napoca) buildings and to demonstrate the economic and environmental benefits of controlling the consumption curve in Blocks of Buildings within several Demand Response programs
Lightning return stroke current reconstruction or vertical and variable channel shape
No full textFirst a new mathematical approach is presented to evaluate the electric and magnetic field of the lightning, via engineering model with variable shape return stroke channel; next, an inverse procedure is exposed for the reconstruction of both spatial and temporal waveforms of the lightning return stroke current, throughout a numerical field synthesis procedure, based on regularization of ill-posed problems. The approach uses as input data the acquisition of time domain recordings of electric and/or magnetic field generated by the lightning current, at various locations on the ground and transforms these signals into harmonics, by Fourier decomposition. This combination, between the proposed solving procedures and harmonic filtering, yields numerical results that are in good agreement with the testing functions
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