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In this research article, new investigation and comprehensive analysis is done on the current distortion effects of dc link inductor and capacitor in variable frequency drive (VFD). Shunt active filter (SAF) is the most prominent solution for harmonic mitigation at the point of common coupling in the power distribution system. However, SAF connectivity reduces the grid impedance ( ZTH ) seen at the input of six pulse diode bridge rectifier in VFD. Commutation behavior of the diode rectifier is changed due to this grid impedance variation resulting in increased harmonic current distortion (THD i ) at the input of the rectifier bridge. This effect increases the ripple current of dc capacitor, dc link inductor losses, and diode rectifier conduction losses. This study investigates the drive dc link inductor and capacitor lifetime reduction with and without SAF, under various grid operating conditions of 3% voltage unbalance and 8% predistortion. Moreover, the high frequency (2–9 kHz) impact on dc link inductor core and copper losses is detailed. A 250 kW VFD with SAF of 180 A capacity is used for test measurement under various operating conditions. Current distortion effects are analyzed, and test results are compared with MATLAB simulation. Grid impedance variation due to SAF and its effect on the reliability of the VFD front-end components were not covered in detail in any of the earlier research. Lifetime estimation of dc link inductor and capacitor due to grid impedance variation is one among the significant outcomes of this investigation.

The global concern with power quality is increasing due to the penetration of renewable energy (RE) sources to cater the energy demands and meet de-carbonization targets. Power quality (PQ) disturbances are found to be more predominant with RE penetration due to the variable outputs and interfacing converters. There is a need to recognize and mitigate PQ disturbances to supply clean power to the consumer. This article presents a critical review of techniques used for detection and classification PQ disturbances in the utility grid with renewable energy penetration. The broad perspective of this review paper is to provide various concepts utilized for extraction of the features to detect and classify the PQ disturbances even in the noisy environment. More than 220 research publications have been critically reviewed, classified and listed for quick reference of the engineers, scientists and academicians working in the power quality area.

Automation technology has brought a pragmatic change in the field of industrial sector, commerce and agricultural sector etc. where machine learning algorithm is one of the pioneers of this. Machine learning has a broad scale application among that anomaly detection is one of the applications. Industrial pumps are essential parts of any kind of industry which requires proper maintenance which is recognized as condition monitoring. The application of machine learning in industrial sectors is going to 65% up to 2018. More will increase in later future. Condition monitoring is the process which cannot prevent failure but can predict the possibility of failure, fault condition by measuring certain machine parameters. If machine learning algorithm can be implemented then the system will be more efficient and it is possible to detect the problems in the ground level which can help to increase the lifespan of the pumping system. Various machine learning algorithms are available among which most of the cases classification and regression analysis are used to detect the anomalies. When there is discrete system generally classification is used and when continuous function is there regression is used. There are more other machine learning algorithms which can analyze the anomalies in the system with the help of predictive control model. The predictive control hybrid model is the new socket of study where the researchers can forecast to shrink the vigor loss of resource and time and can make the system flawless. Thus, there is a big challenge before the researchers regarding the application of machine learning for detecting the anomalies in the pumping system.

Fault-ride-through (FRT) is an imperative capability in wind turbines (WTs) to ensure grid security and transient stability. However, doubly fed induction generator-based WTs (DFIG-WTs) are susceptible to disturbances in grid voltage, and therefore require supplementary protection to ensure nominal operation. The recent amendments in grid code requirements to ensure FRT capability has compelled this study of various FRT solutions. Therefore, for improving FRT capability in pre-installed WTs, re-configuration using external retrofit-based solutions is more suitable and generally adapted. The most relevant external solutions based on retrofitting available are classified as (a) protection circuit and storage-based methods and (b) flexible alternating current transmission system-based reactive power injection methods. However, for new DFIG-WT installations, internal control modification of rotor-side converter (RSC) and grid-side converter (GSC) controls are generally preferred. The solutions based on modifications in RSC and GSC control of DFIG-WT are classified as (a) traditional control techniques and (b) advanced control techniques. This study ensures to curate and compare the FRT solutions available based on external retrofitting-based solutions and internal control modifications. Also, the future trends in FRT augmentation of DFIG-WTs are discussed in this study.

Fault ride through (FRT) capability in wind turbines to maintain the grid stability during faults has become mandatory with the increasing grid penetration of wind energy. Doubly fed induction generator based wind turbine (DFIG-WT) is the most popularly utilized type of generator but highly susceptible to the voltage disturbances in grid. Dynamic voltage restorer (DVR) based external FRT capability improvement is considered. Since DVR is capable of providing fast voltage sag mitigation during faults and can maintain the nominal operating conditions for DFIG-WT. The effectiveness of the DVR using Synchronous reference frame (SRF) control is investigated for FRT capability in DFIG-WT during both balanced and unbalanced fault conditions. The operation of DVR is confirmed using time-domain simulation in MATLAB/Simulink using 1.5 MW DFIG-WT.

The increasing grid integration of wind power has led to the compulsory requirement of low-voltage ride through capability (LVRT) in wind turbines. Grid codes for LVRT capability of wind turbines are proposed in all major wind-energy-producing countries. The testing of LVRT capability compliance of the wind generators as per the specified grid codes during different fault conditions is essential to ensure its reliability. The testing process is generally done by the manufacturers and crucial for certification as per the IEC 61400-21 international standard for measurement of power quality characteristics of wind turbines. This review analyses the various testing tools under the software- and hardware-based categories. The review helps in understanding the present challenges in implementation of wind turbines, to alleviate the difficulty in LVRT testing procedures.

This paper investigates the fault ride through (FRT) capability improvement of a doubly fed induction generator (DFIG)-based wind turbine using a dynamic voltage restorer (DVR). Series compensation of terminal voltage during fault conditions using DVR is carried out by injecting voltage at the point of common coupling to the grid voltage to maintain constant DFIG stator voltage. However, the control of the DVR is crucial in order to improve the FRT capability in the DFIG-based wind turbines. The combined feed-forward and feedback (CFFFB)-based voltage control of the DVR verifies good transient and steady-state responses. The improvement in performance of the DVR using CFFFB control compared with the conventional feed-forward control is observed in terms of voltage sag mitigation capability, active and reactive power support without tripping, dc-link voltage balancing, and fault current control. The advantage of utilizing this combined control is verified through MATLAB/Simulink-based simulation results using a 1.5-MW grid connected DFIG-based wind turbine. The results show good transient and steady-state response and good reactive power support during both balanced and unbalanced fault conditions.

Water pumping system is an essential machinery for residential usage. Around 150 litres of water are used by a person in India daily for their daily usage. For this reason the water pumping is used regularly. Due to dynamic performance of the pumping unit pump can be operated in both no load and load condition. Though the pumping system was controlled by throttling drive in the early stage but in modern technological advancement time pumps are controlled by variable frequency drives (VFD). VFD provides the pump variable duty requirements with significant energy saving and improved reliability. In every pumping system due to dynamic forces of hydraulic and mechanical component some vibrations are seen but sometimes this vibrations may be excessive which can damage the components of the pump. The excessive vibrations indicate some problems or failures in the system. Power quality issues are one of those problems which are seen during the vibration of the pump motor and induction motor connected with pump. This paper presents the power quality issues in the pump motor in different control method like vvc+ and v/f control method.

Controlling the AC motor speed and torque changing voltage and frequency for electrical and mechanical system the adjustable speed drive system is required which is known as Variable Frequency Drive. The usage of VFD is gradually increasing every day. The 25% of the world’s energy is consumed by the motor load for which the usage of VFD is responsible. The cost of VFD can be reduced and size also reduced to help the system more compatible within a very short span of space. It is based on semiconductor topologies, driver circuit, control circuit and both software and hardware devices are also used. Now power quality is the important role plays for the energy efficiency of the system. The researchers are working on various issues of power quality like voltage sag, swell, system unbalance etc. which are required to be analysed for the improvement of the efficiency of the system. In this research the VFD based induction motor faces various power quality issues which are described. The paper is concentrating on various power quality issues which affects the performance of VFD drives through various parameters. The various power quality parameters are predicted for the change in loadings with the help of MATLAB curve fitting tool. With different load variations voltage and current unbalance have been measured. The process has been done though experimental setup with the help of power quality analyser Fluke 302 and both the controller technique like VVC+ and V/F methods have been used.

The traditional configurations of power systems are changing due to the greater penetration of renewable energy sources (solar and wind), resulting in reliability issues. At present, the most severe power quality problems in distribution systems are current harmonics, reactive power demands, and the islanding of renewables caused by severe voltage variations (voltage sag and swell). Current harmonics and voltage sag strongly affect the performance of renewable-based power systems. Various conventional methods (passive filters, capacitor bank, and UPS) are not able to mitigate harmonics and voltage sag completely. Based on several studies, custom power devices can mitigate harmonics completely and slightly mitigate voltage sags with reactive power supplies. To ensure the generating units remain grid-connected during voltage sags and to improve system operation during abnormal conditions, efficient and reliable utilization of PV solar farm inverter as STATCOMs is needed. This paper elaborates the dynamic performance of a VSC-based PV-STATCOM for power quality enhancement in a grid integrated system and low voltage ride through (LVRT) capability. LVRT requirements suggest that the injection of real and reactive power supports grid voltage during abnormal grid conditions. The proposed strategy was demonstrated with MATLAB simulations.