Filter For Mitigation Research Articles

Implementation of fuzzy controller based active filter for harmonic mitigation of grid-connected PV-system

Implementation of fuzzy controller based active filter for harmonic mitigation of grid-connected PV-system

Harmonics management and hosting capacity enhancement: Optimal double-resistor damped double-tuned power filter with artificial hummingbird optimization.

This paper introduces a novel and improved double-resistor damped double-tuned passive power filter (DR-DDTF), designed using multi-objective optimization algorithms to mitigate harmonics and increase the hosting capacity of distribution systems with distributed energy resources. Although four different topologies of single-resistor damped double-tuned filters (DDTFs) have been studied before in the literature, the effectiveness of two different DR-DDTF configurations has not been examined. This work redresses this gap by demonstrating that via comprehensive simulations on two power systems, DR-DDTF provides better harmonic suppression and resonance mitigation than single-resistor alternatives. When it comes to optimizing the DR-DDTF for maximum hosting capacity and minimum system active power losses, the multi-objective artificial hummingbird outperformed six other algorithms in the benchmark. To allow for higher penetration of distributed generation without requiring grid upgrades, this newly developed harmonic mitigation filter provides a good alternative.

Living emission abolish filters (LEAFs) for methane mitigation: design and operation

As one of the most potent greenhouse gases, methane is a critical target for the near-term mitigation of global warming. Efficient, scalable, easy-to-implement, and robust mitigation technologies are urgently needed to assist in reaching methane abolishment. The goal of this research was to test the applicability of active, extremophilic methanotrophic cells as a baseline concept for engineered systems aiming at methane capturing. The system, named living emission abolish filters (LEAFs), represents an array of immobilized biomaterials capable of capturing methane directly from vent streams. The biomaterials were made using cells of Methylotuvimicrobium alcaliphilum 20ZR, a robust halophilic methanotrophic bacterium with the ability to consume methane gas at low concentrations. Several critical parameters were tested, including (i) the composition of the matrix and optimal immobilization to increase catalyst load, (ii) the stability of methanotrophic cells, and (iii) the toxicity of trace gases (i.e. CO). We found that hydrogels coated with 2.3 mg cell dry weight/cm3 methanotrophic cells represent the best-performing biomaterials. The methane reduction potential of LEAFs fluctuated from 20% to 95% and depended on the methane concentration in the gas stream and the stream flow rates. The potential for commercial-scale deployment and emissions reductions was also evaluated. Total greenhouse gas emissions (combined using the global warming potential GWP100) from an example using a ventilation air methane source over a one-year period was shown to be reduced in two LEAF scenarios by 51% and 75%. Over longer time horizons, more significant reductions are possible as consistent methane consumption can be sustained. The study highlights the overall potential of the liquid-free bio-based composite methane mitigation system. Further improvements essential for system assembly and implementations should include (a) optimization of the cell immobilization protocols to improve cell load and the shelf-life of the system and (b) implementation of matrix moldings for cell immobilization to achieve optimal gas flow and increase the cell-gas interface.

A developed DQ control method for shunt active power filter to improve power quality in transformers.

Power transformers are the most important component in power system. Exposing these transformers to the harmonic distortions causes additional heat losses, insulation stress, decrease in lifetime of insulation, and reduced power factor with decrease in efficiency of the system. The lifespan of distribution transformers is influenced by the fragility of power quality in power networks. Harmonic mitigation filters with robust control technique are required to reduce the harmonic effects on power transformer. Traditionally, synchronous reference frame (DQ) is employed to control the shunt active power filter (APF) for mitigation of harmonics in power transformers. DQ control of Shunt APF lacks merits of fast response, delayed operation due to phased lock loop under abnormal grid conditions leading to insufficient harmonic elimination. A developed DQ method based on detecting the positive and negative sequence components is proposed to precisely control the shunt APF for reliable operation of power transformer. This detection technique improves the response time, mitigate the harmonics effecting the operation of transformer and overall power factor. The proposed control system is evaluated under different abnormal operating scenarios and compared with traditional DQ method. The results and analysis confirm the efficacy of the developed DQ method in improving the power transformer performance.

Comparison of APF and STATCOM for Current Harmonic Mitigation

The application of solid-state electronic devices has recorded a geometric increase in the last decade. Devices such as battery charging systems, inverters, switch mode power supplies and a host of electronic-based devices referred to as non-linear loads distort the source signal (particularly the current). Harmonics distortion imposes a severe impact on the well-being of the power system. They cause excessive device heating, reduced performance efficiency, early insulation failure, decreased dynamic torque in rotating systems, etc. This paper bases a study on Active Power Filter (APF) and Static Synchronous Compensator (STATCOM) for mitigation of these distortive harmonics in a system of 3-phase 11kV/400V, 400kVA feeding a system of non-linear loads. The study is based on the IEEE519 standard limits for current harmonics measured at the PCC. Therefore, the system short circuit ratio (SCR) is first determined. Using synchronous reference frame and instantaneous reactive power theories, the APF and STATCOM are respectively designed and run using MATLAB/Simulink software. The result analysis is obtained from the FFT signal processing toolbox of the software, and the device’s performances are evaluated based on the set standard. Results from the FFT spectra showed that the model system contains a considerable number of harmonics before filtering. However, when these devices are connected to the system, all higher-order harmonics have been minimized to the least fractions with respect to the standard, with STATCOM giving a comparatively better performance.

TLBO-trained ANN-based Shunt Active Power Filter for Mitigation of Current Harmonics

The increased utilization of nonlinear devices is resulting in damage to power distribution infrastructure by introducing harmonics into power system networks, which in turn causes distortion in voltage and current signals. A novel solution called Shunt Active Power Filter (SAPF) has been developed to address this issue using power electronics. This study aims to provide a method that is efficient and cost-effective for lowering harmonics and improving power quality in distribution infrastructure. The proposed method combines the Teaching learning-based optimization (TLBO) technique with an Artificial Neural Network Controller (TLBO-ANN) in conjunction with SAPF. The primary objective of the TLBO-ANN algorithms in SAPF is to minimise total harmonic distortion (THD) for maximum system efficiency. Initially, Gain values (Ki, Kp) for a regular Proportional-Integral controller are optimised with the Particle Swarm Optimisation (PSO) technique. Those optimized parameters obtained from the PSO-tuned PI controller serve as input and target datasets for training the ANN controller. Subsequently, the TLBO algorithm is utilized to further refine the ANN controller by finding the optimal weight and bias values. Using MATLAB/SIMULINK software, we compare the performance of the proposed algorithm to that of the PSO-tuned PI controller and traditional PI controller. The findings from the simulation suggest that a SAPF utilizing a TLBO-trained ANN controller could improve THD in the supplying current while maintaining harmonics within IEEE-519 accepting levels.

Optimal design of shunt active power filter for mitigation of interharmonics in grid tied photovoltaic system

Optimal design of shunt active power filter for mitigation of interharmonics in grid tied photovoltaic system

Superconducting Notch Filter for RFI Mitigation in Ground-Based Radio Telescope

This article presents a high-rejection, thin-film high-temperature superconductor, microstrip bandstop filter to prevent a local, and high-power radio-frequency interference (RFI) source from interfering with NASA Goddard Geophysical Astronomical Observatory (GGAO)’s very long baseline interferometry (VLBI) global observing system (VGOS) cryogenic receiver. This filter has an excellent 2.7%, 50-dB-fractional-bandwidth, and a center stopband frequency of 9.41 GHz. It does not contain any narrow or interdigital features as found in some designs, which reduces the fringing electric fields and improves its power handling capability. The YBCO films were grown on 435- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m-thick R-plane sapphire substrate and the anisotropic behavior was modeled and simulated with a high degree of accuracy. The device was tested while cooled to 77 K and the measurements agree well with simulation.

Implementation of Novel Reduced-Order H∞ Filter for Simultaneous Detection and Mitigation of FDI-Attacks in AGC Systems

Recent developments in power systems to build a smart grid depend critically on communication networks which provide unprecedented advantages for comprehensive system visibility, monitoring, protection, and control. However, it increases the system complexity and vulnerability to cyberattacks that could jeopardize the seamless system operation. The attack must be detected effectively, and then proper measures to mitigate the effect quickly to restore normality. This work implements a reduced-order <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\infty }$ </tex-math></inline-formula> filter to simultaneously estimate the state variable and unknown inputs such as noise or attack signals in the automatic generation control (AGC) system. Further, the knowledge of the disturbances is utilized to mitigate the attack by appropriately compensating the sensor readings, such that the control decisions are based on the correct states, not the corrupted signals generated in the attack scenario. The stability criterion is provided based on Lyapunov functions to check the estimation error in the presence of the exogenous disturbance. Further, the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\infty }$ </tex-math></inline-formula> estimator performance is evaluated by comparing it with the Kalman filter to verify its effectiveness. The estimator’s performance is validated by developing a cosimulation platform using the server–client architecture of data exchange. Further, the performance is validated in a real-time digital simulator (RTDS) platform used as the power system interacting with an estimator deployed on Raspberry Pi board sensing the attacks.

Feasible Evaluation and Implementation of Shunt Active Filter for Harmonic Mitigation in Induction Heating System

This paper proposes a shunt active filter (SAF) for harmonic mitigation and reactive power compensation in an induction heating (IH) system. The high-frequency switching in the resonant inverter of the IH system generates a considerable number of high-frequency harmonics. The latter flow back to the supply side and causes a wide variety of problems. The predominant ones are the deterioration of the power quality, distortion in the grid voltage, and malfunctioning of the protective equipment. These harmonics need to be attenuated as per the IEEE 519-1992 and IEEE 519-2014 standards. To overcome these problems, an SAF based on the modified version of instantaneous power theory was placed between the power supply and the IH equipment. Moreover, the proposed model could work in unbalanced and non-sinusoidal input voltage conditions, as well as dynamic conditions with changing reference currents. The feasibility of the proposed SAF-based IH system was verified by a series of simulation results and a comparative analysis of the THD of the input currents. The power quality issues were successfully addressed, which signifies the ability and effectiveness of the proposed model to mitigate the problems caused by harmonics and enhance the power factors.

Performance Analysis of Three-Phase Shunt Active Power Filter for Harmonic Mitigation

Aims: To carried out performance analysis of a shunt active power filter (SAPF) for harmonics mitigation.&#x0D; Study Design: Experimental design through simulation studies using P-Q Theory and proportional integral controller.&#x0D; Place and Duration of Study: Department of Physics, Nasarawa State University Keffi, main campus, Nigeria, between October 2020 and September 2021.&#x0D; Methodology: Primary and secondary data were obtained using AVO Digital Multimeter and manufacturers’ datasheets from Schneider electric website to capture required system parameters, SAPF was designed using a Voltage Source Inverter model to represent the Three-Phase source, and P-Q Theory with PI Control was used for reference current extraction. The SAPF was modeled, designed and simulated using MATLAB-Simulink and analyzed under different nonlinear load conditions and harmonic spectrum to achieve low Total Harmonic Distortion (THD).&#x0D; Results: The THD in the unbalanced system voltages before the application of SAPF was found to be 12.6%, 11.4% and 11.2%, while after the application of SAPF was 2.2%, 2.5% and 2.5% for phase voltages a, b and c respectively. The grid currents indicated THD of 27.2%, 30.9% and 31% before application of SAPF and 2.2%, 2.2% and 2.1% after application.&#x0D; Conclusion: The use of non-linear loads; has adverse effects on the quality of electric power as well as phase voltage and frequency waveforms. The use of SAPF is of vital importance in improving electric power quality for reliable power supply and quality service delivery.

COMPENSATION OF HARMONICS TO IMPROVE POWER QUALITY USING HYBRID ACTIVE POWER FILTER

This paper presents design, simulation and development of hybrid active power filter for mitigation of the power quality problem at ac mains in ac-dc power supply feeding to a nonlinear load. The power filter is consisting of a shunt passive filter connected in series with an active power filter. At first passive filter has been designed to compensate harmonics. The drawback associated with the passive filter like fixed compensation characteristics and resonance problem is tried to solve by HAPF. Simulations for a typical distribution system with a hybrid power filter have been carried out to validate the presented analysis. Harmonic contents of the source current has been calculated and compared for the different cases to demonstrate the influence of harmonic extraction circuit on the harmonic compensation characteristic of the shunt hybrid power filter.

Adaptive Neural Network for a Stabilizing Shunt Active Power Filter in Distorted Weak Grids

Harmonics destructively impact the performance and stability of power systems. This paper proposes the development of a stable shunt active power filter (SAPF) for harmonics mitigation. The proper and stable operation of the SAPF control system requires the determination of the current reference, phase angle synchronization, and DC-link voltage regulation. This paper uses an artificial neural network (ANN) and one of its sub-methods, the adaptive linear neuron (ADALINE), to determine the current reference. However, determining the current reference requires providing a stable phase angle, which is a fundamental challenge in distorted grids because harmonics created in the grid cause phase angle synchronization problems, due to malfunction of the conventional phase-locked loop (PLL). These things considered, the weak grid connection imposes an instability issue due to the poor performance of the conventional PLL when the grid impedance is high. In this paper, a robust synchronous filter (RSF) is adopted, which separates the harmonic from the main component to provide harmonics-free signals for the PLL. Using RSF, a robust synchronizer quasi-static filter (RSQSF) PLL model is designed, which is effective in dealing with harmonics in weak-grid conditions. MATLAB Simulink was used to check the validation and effectiveness of the proposed control structure. The results show a reduction in harmonics generated in the grid by 86.7% for nonlinear load with a balanced source, 84% for nonlinear load with an unbalanced source under grid impedance, and 80.46% for the nonlinear load with an unbalanced source under weak-grid conditions.

A low-loss passive filter for overvoltage mitigation of inverter-driven motors with ultra-long cables

Variable frequency drives (VFDs) are always considered in industrial applications because of their benefits. However, in applications with long cables, overvoltage spikes appear at the motor terminal due to the reflection phenomenon, causing the premature failure of the motor. Various passive and active techniques have been proposed to solve this issue. Among them, passive techniques are preferred due to their simplicity, low cost and effectiveness. However, the use of passive filters in ultralong cables is limited due to additional power dissipation. In this paper, L-RC filter is presented and shown to be efficient for ultra-long cables. The proposed filter does not have the limitations and problems associated with the conventional L and RC filters. The PWM inverter-fed ac motor drive system is fully modelled to evaluate the performance of the proposed filter. The presented model is simulated in the Matlab software and the effect of different parameters on the filter performance is evaluated. Finally, in an actual 37 kW system, the performance of the proposed filter is compared with that of the conventional filters. The experimental results show the good performance of the proposed filter in reducing the voltage overshoots, increasing the rise time and decreasing power dissipation.

A 67-mW D-Band FMCW I/Q Radar Receiver With an N-Path Spillover Notch Filter in 28-nm CMOS

A 139.5–157.7-GHz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band I/Q radar receiver with an on-chip antenna and a spillover resilient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> -path baseband filter is presented. Spillover and its manifestation based on the chirp duration are discussed, and a filter for spillover mitigation is implemented. The radar is characterized by 18-GHz radio frequency (RF) bandwidth, 13-mm range resolution, 55-dB conversion gain, 8-dB NF, and 26-dB narrowband spillover attenuation. The receiver is also capable of selectively mitigating close-by large reflectors, and the system power consumption is 67 mW.

Envelope Detection by Shannon Energy Calculation in DCT Domain and DFS-Based Notch Filter for Interference Mitigation in GNSS Receivers

A new pre-correlation technique to enhance the Global Navigation Satellite Systems (GNSS) receivers, against the continuous wave interferences (CWI), is presented. Accordingly, the detection and the localisation procedure are constituted of many steps. First, the discrete cosine transform (DCT) is applied on the contaminated signal. Next, the Shannon-energy envelope detector, in the DCT-domain, is accomplished. Then, all envelope magnitudes above a predefined threshold, representing the interference components, are localized in the frequency domain. The following step consists in the use of the discrete Fourier series (DFS) technique to calculate the corresponding contributing harmonics of the CW interferences. Finally, the interference is reduced efficiently by a subtraction of its approximated version from the original contaminated signal. The results provided from the simulation prove that the DFS-based notch filter in terms of signal quality restoration, for both single-tone and multi-tone, is of superior performance compared to the classical notch filtering.

Assessment of Harmonic Mitigation in V/f Drive of Induction Motor Using an ANN-Based Hybrid Power Filter for a Wheat Flour Mill

Voltage/frequency (V/f) drive of a three-phase induction motor plays a crucial role in a flour mill for energy saving. Wheat consumption in India is increasing day by day, which reached 105,000 metric ton (MT) in 2021. India’s high wheat consumption and production increase flour mills. Thus, energy efficiency in a flour mill is a must in the present situation. Hence, V/f drives are widely used in flour mills. Apart from the advantages of V/f drive, electronic circuits in a drive induce harmonics in a power system. Power quality plays a vital role in a modern power system. Harmonics by V/f drive increase the current consumption, causing increased losses, cable overheating, and motor overheating, which necessitates a filter for harmonic mitigation. In this paper, an artificial neural network controller-based hybrid power filter is proposed for harmonic mitigation. A hybrid power filter (HPF) is presented to overcome the problems and achieve the active and passive power filter’s benefits. Harmonic mitigation of the proposed hybrid power filter is compared with the passive and active filter-based drives. This paper analyzes harmonic mitigation for three-phase induction motors with V/f drive installed in a 300-ton/day wheat flour mill’s purifier fan. The performance of the suggested system is analyzed under various speeds in the aspects of harmonic mitigation, reduction in current consumption, and energy saving using various filters. The entire system is developed and analyzed using MATLAB/Simulink. Energy saving is increased by around 10.97 kWh per year by HPF by means of reducing harmonics and current consumption compared to an active power filter, while it is increased by around 28.16 kWh/year compared to a passive power filter. Along with the harmonic mitigation, energy saving is also validated for various filters under various speeds.

Fuzzy gain Scheduled PID Controller for Power Quality Enhancement in Grid Connected Hybrid Solar PV-PEMFC Energy System

Power quality improvement is inevitable due to the presence of power converters and non-linear loads in grid connected renewable based hybrid energy system (HES). The harmonics introduced by the distributed energy systems may lead to output voltage distortion andequipment failure which may lead to system losses. It may also cause for direct and indirecteconomic impacts. Development of active filter, passive filter and hybrid filter for harmonics mitigation would be an expensive solutions. Therefore, various DC/AC converter switchingschemes are proposed for power quality improvements in grid connected Solar Photovoltaic(PV) and fuel cell based HES. Initially, Solar PV and Proton Exchange Membrane Fuel cell (PEMFC) are modeled using MATLAB/Simulink. Further the harmonic behavior withProportional plus Integral (PI), Proportional plus Integral plus Derivative (PID) and Fuzzygain scheduled PID controllers are demonstrated using Pulse Width Modulator (PWM).Converter output voltage waveform, frequency spectrum and total harmonics distortion (THD) values at the Point of Common Coupling (PCC) have witnessed that the fuzzy gain scheduled PID controller suppresses the voltage distortions completely. It also yields 4 percentage THD value which satisfies the harmonic level recommended by IEEE 519 standard. Comparative analysis shows that the fuzzy gain scheduled PID control scheme exhibits superior performance than the traditional PI and PID controllers. Therefore, it is identified as an effective control scheme for power quality improvement in hybrid renewable energy system.

A Transformerless AC-AC Converter with Improved Power Quality Employed to Step-Down Power Frequency at Output

Variable voltage and frequency are required to govern the torque-speed characteristics of many industrial drive systems. Traditionally, this is achieved with a power converting system implemented with multistage converters. This technology is based on rectifying AC power into DC and then DC into AC with an inverter circuit. The power quality concerns of both conversion stages are tackled by selecting high switching frequency PWM control and harmonics mitigation filters. Also, using a bulky DC-link capacitor is one of the big sources of low system reliability, so this approach increases the conversion losses, circuit, and control complications. The frequency step-down conversion is very attractive with direct AC-AC converters as it has a simple control and circuit structure, but these converters face poor power quality challenges once the output frequency is decreased with respect to an input. In these converters, the total harmonic distortion (THD) of the output voltage becomes very poor once the output frequency is reduced. The problem of high THD of the output is addressed in the power converting circuits implemented with line frequency multi-winding transformers. The required number of output winding and switching devices (diodes and thyristors) increases once the value of the output frequency is decreased. This will increase the overall volume, cost, and losses. The use of a bulky and costly line frequency transformer may be eliminated if AC voltage controllers have non-inverted and inverted voltage buck capabilities, such existing topologies either have complex control schemes or require a large number of operating devices. Therefore, in this research article, a new transformerless frequency step-down converter employing fewer devices is proposed. This approach is realized with a high-frequency controlled rectifier for the required voltage stabilization and a low-frequency inverter bridge for frequency control. Its validation is supported by the results attained from Simulink and practical-based prototypes.

Radio Frequency Interference Characterization and Mitigation for Polarimetric Weather Radar: A Study Case

Radio frequency interference (RFI) has become a growing concern for weather radar, distorting radar variable estimation. By simultaneously or alternately transmitting the horizontal and vertical polarized waves, polarimetric weather radar can be referred to as SHV radar or AHV radar. The SHV radar can mimic the AHV radar by discarding either H- or V-channel measurements, which leads to an alternating scheme. In this research, the real RFI measurements from an operational C-band SHV radar are used to characterize the RFI temporal, spectral, and polarimetric features. Then, the RFI is simulated to quantify the performance of the object-orientated spectral polarimetric (OBSPol) filter in RFI mitigation. The OBSPol filter has been previously proposed by the authors to mitigate the narrowband clutter (both stationary and moving) and noise. This work extends the application of the filter to remove the RFI for SHV radar. Specifically, by taking advantage of the low copolar correlation of the RFI signal measured in AHV radar, the RFI mitigation method is designed, and its effectiveness is proven by qualitative and quantitative analyses. In particular, in the case of RFI overlapped to weather echoes in the time domain, the RFI can be mitigated, also when the duty cycle of the RFI is high. However, this work does not provide a full evaluation of the RFI mitigation performance on all radar data outputs but a proof of concept to show the effectiveness of the proposed filter for RFI mitigation.