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Power quality is an importance term used for measuring quality of Electrical supply to an industrial, domestic and commercial loads. In an Electrical industry, Power quality is primarily a main concern. The power quality issue occurs when the system load in the power system is affected with problems such as transients, harmonics and voltage sag and swell. Hence the power quality issues needed to be...
This paper investigates the impacts of distributed generator such as solar PV and energy storage on the utility grid. Initially experiment was conducted by increasing PV penetration into the grid and analysed the voltage fluctuation at PCC and harmonic emission on the network. Later, a software model was developed and same impacts were investigated with increased penetration of solar PV. The model...
Electric arc furnace and its influence in the power system are studied in this paper. Two models that allow to evaluate its behavior during steady state are shown. These models has different complexity level; the first model takes into account the main nonlinearities of the load; the other assumes that current-voltage characteristic in the arc is piece-wise linear. Electromagnetic transients program...
This paper is focused on measurement and analysis of supply voltage level in low voltage industrial power systems in Estonia. A practical method for analysis of supply voltage quality parameters implementing stochastic theory is discussed. Measurement results of supply voltage quality parameters — voltage magnitude, voltage level and voltage sags in industrial 0.4 kV power systems of Estonia are shown...
It is known that a direct application of artificial neural network (ANN) for modeling high power, nonlinear, and impact load may lead to inaccuracies. This paper proposes an approach that the characteristic of the high power, nonlinear and time varying load is modeled by advanced ANN, which is implemented by using back propagation network (BPN) and dynamic time warping (DTW) algorithms. The model...
This paper presents a method that the voltage/current characteristic of the high power, nonlinear and time varying load is modeled by using artificial neural network, this method is implemented by using back propagation network and look up tables which accurately establish high power load model and receive the consumption of the active, reactive and apparent power and voltage distortions in different...
In this paper, a novel effort for prediction of voltage sag in the entire transmission system of Vietnam is presented. As the Vietnamese electricity industry moves toward the electricity market, prediction will help utilities have early assessment of power quality in transmission system. The proposed prediction approach uses a fault position method in which the fault distribution in the transmission...
When only measurements at the source of flicker are available, flicker levels in other network nodes can be obtained with stationary calculation methods. When dealing with multiple flicker sources it is vital to assess their cumulative contribution to flickers levels in network nodes using flicker summation factors. The paper presents a case of two arc furnaces causing flicker in a particular node...
This paper proposes a new control method for D-STATCOM (Distribution STATIC Compensator) control system. The operation of this proposed control method enables D-STATCOM to mitigate all types of fault, intelligently (such as Single Line to Ground (SLG) fault and Double Phase to Ground (DPG) fault and three-phase fault). In this paper, the 12-pulse D-STATCOM configuration with IGBT is designed and the...
Stationary and dynamic flicker calculation methods are often used for assessing flicker levels throughout the network. This paper introduces a method for calculating flicker levels in the network by analyzing the propagation of voltage interharmonics. Calculated flicker levels are compared with the measurement results. Simplifications of this method are tested on numerous examples.
The present paper introduces some simulation methods for flicker propagation assessment. The first method is based on current injection into the system matrix of the studied grid. Only one computation is enough to get all nodal voltages of the grid. We can thus deduce flicker propagation coefficient between any two nodes by the ratio of the relative nodal voltages. The second method requires two load-flow...
Most of the dispersed generation systems (DGS) have smaller installation capacity and have to be connected to the distribution network to supply electric power into the utility as well as local loads. When the DG is interconnected in parallel with the utility distribution system, some operating conflicts might arise that affect the system power quality. This paper investigate the effect of DG on the...
This paper deals with modeling and simulation technique of a Dynamic Voltage Restore (DVR). The DVR is a dynamic solution for protection of critical loads from voltage sags / swells. The DVR restores constant load voltage and voltage wave form by injecting an appropriate voltage. Present novel structure improves power quality by compensating voltage sag and voltage swells. This paper discussed abc...
Hydro-Quebec aims saving energy by controlling the voltage level and by managing the reactive power (vars) in the distribution network. For this, it will use a VVC system, which requires a permanent surveillance of the voltage level at the end of the distribution feeder and the installation of switching shunt capacitor banks.
This paper deals with the design, analysis and simulation of an online voltage envelope estimator and an online feed-forward neural network (FFNN) controller based distributed static compensator (DSTATCOM) controller. Existing controllers such as PI controller and offline neural network controller are fixed structures and provide satisfactory control only for certain problems for which they are designed...
Under the scope of the IEC technical report 61000-3-7, the principles to assess flicker emission limits for the connection of fluctuating loads to the public network power system have been outlined. This technical report gives also the definition of the flicker emission level. But this report does not explain how to measure and assess the flicker emission level. Actually, because of the existence...
In order to determine the impact of a fluctuating load on a utility system, the engineer needs accurate measurement and modeling devices. The purpose of this paper is to show methods used in predicting flicker on the utility system due to projected changes in loads. The goal is to demonstrate the usefulness and accuracy of newer measuring and modeling techniques.
Dynamic load models are of growing importance to the studies of power system dynamic analysis. However, the efficiency of such a model depends on the accuracy of model's parameter set. We propose a relatively new approach called particle swarm optimization (PSO), which has already been applied in various other fields and has been reported to show effective and efficient performance, to estimate the...
The voltage dip has been a problem from the increase of the customer loads such as an electronics devices etc. and the electric power quality needs. This paper shows the voltage analysis system for the customer including dip measures. The first characteristic of this system is to predict the voltage dip performance of customer loads and the effect of voltage dip measures applied to loads conditions...
Voltage flicker and harmonics are the power quality problems which are introduced to the power system as a result of nonlinear and stochastic behavior of the arc furnace operation. In the first part of the paper, different arc furnace models with different level of complexity, for flicker study are reviewed. Simulation results are also provided. In the second part of the paper, a new developed time...
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