Impact Of Harmonic Distortion Research Articles

Integration studies of RF solid-state generators in the electrical system of NBTF experiments and ITER HNB

SPIDER operation, started in 2018, pointed out performance-limiting issues caused by the technology employed in RF generators, based on tetrode free-running oscillators. One of these limits, namely the onset of frequency instabilities, prevented operation at the full rated power of 200 kW. In addition, tetrodes require high voltage to operate, which translates to risk of flashovers and the necessity to perform conditioning procedures, limiting the overall reliability. These disadvantages, combined with the positive experience gained in the meanwhile on smaller facilities with solid state amplifiers, led to the proposal of a complete re-design of the radiofrequency power supplies. This paper describes the modelling activities used to define specifications and design criteria of the solid-state amplifiers for SPIDER and MITICA, which can be directly transposed to the ITER HNB units when their functionality is proven. We detail the topology of the generators, consisting of class D amplifier modules combined to achieve the required 200 kW, which design is mainly driven by the necessity to deliver nominal power to the ion source, mitigate the risk of obsolescence, and improve the reliability through modularity. Due to the non-standard application, we gave particular focus to the integration of generators in the RF systems of SPIDER and MITICA. Numerical analyses were performed to verify the impact of harmonic distortion on transmission line and RF load components, to address the effect of mutual coupling between RF circuits on the generator output modulation, and to assess the magnitude of common mode currents in the electric system. These studies, as well as the experience gained from SPIDER operation, helped to define dedicated circuit design provisions and control strategies, which are currently being implemented in the detailed design and construction phase of the new RF amplifiers.

Impact of harmonic distortion on the supraharmonic emission of pulsewidth modulated single-phase power electronic devices

This study demonstrates the frequency coupling in pulse width modulated (PWM) single-phase converters and inverters. As current state of the art, the harmonic frequency range, e.g. from fundamental frequency up to 2 kHz, is typically assessed separately from the so-called supraharmonic frequency range, i.e. above 2 kHz up to 150 kHz. The frequency coupling between the harmonic and supraharmonic frequency range has not been thoroughly studied and is currently often neglected in the design process as well as for the analysis of the emission of power electronic devices. The aim of this study is to analyse the behaviour of the frequency coupling between the harmonic and the supraharmonic range. In addition, laboratory measurements of a commercially available single-phase inverter for photovoltaic applications are shown to verify the findings.

Improving Power Quality and Mitigation of Harmonic Distortion Impact at Photovoltaic Electric Vehicle Charging System

This article offers a clear and realistic design for an active power filter to increase reliability and power quality of the photovoltaic charging system and a high-penetration electric vehicle distribution system. The MOPSO algorithm is used as the basis for problems with optimization and filter tuning. A typical regular load curve is used to model the warped power grid over a 24-hour cycle to estimate the total harmonic distortion (THD). For structures with high penetration of electric cars, the probability of minimizing THD (for example to five percent) is explored via optimum capacity active shunt filters and shunt capacitors. To maximize general performance of the charging system, the switching systems are re-scheduled. Moreover, to increase the current control accuracy of shunt active filter, the fuzzy logic controller is utilized. The major drawback to new system is that it would have unrestricted billing for entire day to cope with voltage interruption. In MATLAB / SIMULINK, detailed machine setup and control algorithm experiments are simulated. The simulation findings confirm the efficiency and viability of projected shunt active filter to enhance voltage profile and track power performance of photovoltaic charging system.

Harmonic analysis of thyristor controlled series capacitor in polluted Algerian network

This paper presents the study of the impact of harmonic distortion generated by the thyristors controlled series capacitor (TCSC) in Algerian electric power system. By applying Fourier transform of terminal voltage and switching function, the TCSC model is used as a harmonic admittance matrix, in the frequency domain, and then integrated into a balanced harmonic load flow algorithm based on the Newton-Raphson method. The study has been carried out with the equivalent Algerian power system 114 bus. The total harmonics and RMS voltages are evaluated under different operating regions of the TCSC.

Minimizing harmonic distortion impact cause by CS using meta heuristic technique

Non-linear load in the distribution system has caused negative impact to its power quality especially on harmonic distortion. Charging Station (CS) is a non-linear load that widely promoted with the aim to support the continuous usage of Electric Vehicle (EV). This research is focusing on optimal placement and sizing of multiple passive filter to mitigate harmonic distortion due to CS usage at distribution system. There are 6 units of CS which being placed in low voltage buses which indirectly will inject harmonic to the system during charging. Power system harmonic flow, passive filter, CS, battery and the analysis will be model in MATLAB. Multi-objective function which are weight summation approach (WSA) and Pareto Front are used to assist meta heuristic technique which is Modified Lightning Search Algorithm (MLSA) to identify optimum location and sizing of passive filter based on improvement on propose five parameters. From the result, the optimal placements and sizing of passive filter able to reduce the maximum Total Harmonic Distortion (THD) for voltage, current and apparent losses respectively. Therefore, the propose method is suitable to reduce harmonic distortion as well as apparent losses at distribution system with present of CS.

Differences in the impact of harmonic distortion due to the installation of electronic load controller in self-excited induction generator and synchronous generator

In general, the application of Self-Excited Induction Generator (SEIG) or Synchronous Generator (SG) on the Stand-Alone Micro Hydel Power Plant (MHPP) is equipped with Electronic Load Controller (ELC) to control generator output during variations in consumer load. One type of ELC that is cheap and rigid developed today is the ELC, which is constructed by the uncontrolled bridge rectifier with DC Chopper. Based on the operational concept, basically this type of ELC can be implemented on both SEIG and SG, but both of these generators will have a different harmonic distortion effect on the output and its load. This paper examines the differences in the effects of harmonic distortions due to ELC installation on SEIG and SG. The initial stage of this study was to design the ELC developed. Then, the harmonic distortion response due to the installation of ELC on SEIG and SG is tested, which includes harmonic distortion in: stator current, PCC voltage, and consumer load current. THD<sub>I </sub>(Current Total Harmonic Distortion) stator current at SEIG with ELC has shown an average value smaller than the THD stator current in SG with ELC. Likewise, the THD<sub>V</sub> (Voltage Total Harmonic Distortion) value of PCC voltage and THDI value of the current consumer load on SEIG equipped with ELC has been shown to be smaller than the THD<sub>V</sub> value of PCC voltage and THD<sub>I</sub> value of the current consumer load on SG equipped with ELC. The effects of harmonic distortions due to the installation of ELCs that developed in this study on SEIG is still within the permitted limits, while on the SG, the harmonic distortion reduction is needed at the generator output.

Evaluation of Harmonics Impact on Digital Relays

This paper presents the concept of the impact of harmonic distortion on a digital protection relay. The aim is to verify and determine the reasons of a mal-trip or failure to trip the protection relays; the suggested solution of the harmonic distortion is explained by a mathematical model in the Matlab Simulink programming environment. The digital relays have been tested under harmonic distortions in order to verify the function of the relays algorithm under abnormal conditions. The comparison between the protection relay algorithm under abnormal conditions and a mathematical model in the Matlab Simulink programming environment based on injected harmonics of high values is provided. The test is separated into different levels; the first level is based on the harmonic effect of an individual harmonic and mixed harmonics. The test includes the effect of the harmonics in the location of the fault point into distance protection zones. This paper is a new proposal in the signal processing of power quality disturbances using Matlab Simulink and the power quality impact on the measurements of the power system quantities; the test simulates the function of protection in power systems in terms of calculating the current and voltage values of short circuits and their faults. The paper includes several tests: frequency variations and decomposition of voltage waveforms with Fourier transforms (model) and commercial relay, the effect of the power factor on the location of fault points, the relation between the tripping time and the total harmonic distortion (THD) levels in a commercial relay, and a comparison of the THD capture between the commercial relay and the model.

Minimization of harmonic distortion impact due to large‐scale fast charging station using Modified Lightning Search Algorithm and Pareto‐Fuzzy synergistic approach

The increased number of nonlinear loads in the distribution system has caused a significant impact on its power quality in the form of higher harmonic distortion. The fast charging station (FCS) is an example of a powerful nonlinear load that is currently being widely promoted with the aim of supporting the continuous usage of electric vehicles (EV). The most common and cheapest method to minimize harmonic impact is through the use of a passive filter. This paper presents an optimal sizing and placement of a passive filter design based on the numbers of FCS installed in the distribution system. The MATLAB/m‐file platform is used to model the power system harmonic flow, passive filter, and FCS. The control strategy used to minimize the total harmonic distortion (THD) due to the large number of FCS is presented based on the selection of optimal location and the size of passive filters that will provide minimum THD and apparent power losses to the overall distribution system. A Modified Lightning Search Algorithm (MLSA) technique is applied with the aim of identifying the optimal solution. The Pareto‐Fuzzy technique is used to obtain a better solution among nondominated solutions. From the result, the optimal placements and sizes of passive filter will be able to reduce the maximum THD and also the total losses in the distribution system, which is equipped with 17 FCS units. This study is useful as a guide for grid owners to control the impact of large‐scale FCS deployment in the distribution system. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Minimizing Harmonic Distortion Impact at Distribution System with Considering Large‐Scale EV Load Behaviour Using Modified Lightning Search Algorithm and Pareto‐Fuzzy Approach

This research is focusing on optimal placement and sizing of multiple variable passive filter (VPF) to mitigate harmonic distortion due to charging station (CS) at 449 bus distribution network. There are 132 units of CS which are scheduled based on user behaviour within 24 hours, with the interval of 15 minutes. By considering the varying of CS patterns and harmonic impact, Modified Lightning Search Algorithm (MLSA) is used to find 22 units of VPF coordination, so that less harmonics will be injected from 415 V bus to the medium voltage network and power loss is also reduced. Power system harmonic flow, VPF, CS, battery, and the analysis will be modelled in MATLAB/m‐file platform. High Performance Computing (HPC) is used to make simulation faster. Pareto‐Fuzzy technique is used to obtain sizing of VPF from all nondominated solutions. From the result, the optimal placements and sizes of VPF are able to reduce the maximum THD for voltage and current and also the total apparent losses up to 39.14%, 52.5%, and 2.96%, respectively. Therefore, it can be concluded that the MLSA is suitable method to mitigate harmonic and it is beneficial in minimizing the impact of aggressive CS installation at distribution network.

Improved Synchrophasor Models for Power System Dynamic Stability Evaluation Based on IEEE C37.118.1 Reference Architecture

Synchrophasors are an emerging power system wide-area dynamic performance monitoring and control technology. The IEEE standard C37.118.1 outlines specifications for the construction of synchrophasor units, in which two reference synchrophasor models are proposed for protection (P-type) and measurement (M-type) purposes. This paper develops improved synchrophasor models for power system dynamic stability/performance evaluation based on the reference architecture proposed in the IEEE standard C37.118.1, considering frequency error (FE) and the total vector error (TVE) as the main performance indices. The quadrature demodulation filters are designed explicitly considering the impact of harmonic distortion and out-of-band interference, and thus optimized quadrature demodulation filters improve estimation performance during adverse conditions. Furthermore, a special emphasis is placed on the input low-pass filter to attenuate high-frequency components above the Nyquist rate. The improved synchrophasor models are rigorously tested to ensure compliance with performance requirements stipulated in the IEEE standard. Results show that improved synchrophasor models significantly enhance the FE while ensuring compliance requirements for the TVE.

Technical and Economic Analysis for Harmonic Distortion Impact and Mitigation Technique in Power Networks

This research proposes technical and economic analysis of harmonic distortion impact and mitigation technique in power networks. Main proposal of research is analysis of harmonic impact and harmonic solution by regarding to economic decency for investment. Parallel resonance is harmonic impact that will be mentioned in this research because it is a problem that is mostly emerged in industries that contain non-linear loads and power factor correction devices. Its impact on power network is high voltage and current amplification, which link to equipment and system failure. An application of detuned filter will be proposed to solve the problem due to its popularity (It is a basic solution, easier and more inexpensive than the other solution). Parallel resonance condition will be modeled with an industrial power network, which contains a power transformer, a non-linear load (AC drive), a power factor correction device (capacitor bank) and a harmonic correction device (detuned filter bank), by using electrical, mathematical and payback period formulas. The results will illustrated the impact of parallel resonance phenomenon due to harmonic distortion in power network.

Modeling and Analysis of Grid Harmonic Distortion Impact of Aggregated DG Inverters

This paper proposes an impedance-based analytical method for modeling and analysis of harmonic interactions between the grid and aggregated distributed generation (DG) inverters. The root cause of harmonic interaction/resonance problems is the impedance-network quasi-resonance between the effective output impedance of the inverter and the equivalent grid impedance at the connection point. Starting with the output impedance modeling of an inverter, a Norton model of the inverter is derived. Comparing with the switching model and the average model of the inverter, simulation results show the effectiveness of the model. This paper proposes that impedance limits should be specified and used as an extra design constraint for DG inverters in order to minimize the harmonic distortion impact on the grid. Assuming the impedance models of individual inverters and local loads within a distribution grid are known, especially in the case of new grids under construction, harmonic interactions between the grid and a certain number of DG inverters can be preliminarily estimated.

Impact of nonlinear distortion in radio over fiber systems with single-sideband and tandem single-sideband subcarrier modulations

In radio over fiber (RoF) systems, two subcarrier modulations (SCMs), i.e., single-sideband (SSB) and tandem single-sideband (TSSB), have been widely used. Both SSB and TSSB SCMs can be obtained using optical Mach-Zehnder modulators. In this paper, the authors theoretically investigate the impact of harmonic distortion and intermodulation distortion in RoF systems for one wavelength carrying two radio frequency (RF) signals with either SSB or TSSB SCM. It is found that nonlinear distortion can be reduced when the frequency difference of two RF signals is /spl sim/ 1 GHz compared with /spl sim/ 2 GHz and higher for both TSSB and SSB SCMs, particularly for large modulation indexes. When the frequency difference of RF signals is /spl sim/ 2 GHz and beyond, either a small modulation index or a medium modulation index combined with a minimum RF of 6 GHz must be used, and a large modulation index cannot be used due to serious nonlinear distortion. Comparison of SSB and TSSB SCMs with uniform distribution of optical signal subcarriers in a dense wavelength-division-multiplexing RoF system with channel spacing of 12.5 GHz shows by simulation that SSB SCM is better (worse) than TSSB SCM for small (large) modulation indexes.