Power Quality Characteristics Research Articles

Performance of Interline Unified Power Quality Conditioner IUPQC With PI, Fuzzy and ANFIS Controllers

Several artificial intelligent control schemes are highly used in several applications, in that ANFIS controller has been greatly recognized due to enhanced performance over the classical PI and Fuzzy controllers. At present the multi-feeder power distribution system is deteriorated with continuity of supply and poor power quality standards. In this multi-feeder distribution system, it is a regular consumer related issue which is acquired due to malfunctioning of massive non-linear loads. These loads create the voltage or current imperfections on distribution networks which disrupts the power quality of distribution system. An efficient and reliable active compensation scheme is used for attaining enhanced power quality features at PCC of multi-feeder distribution system with effective control functions. The Multi-Feeder Unified Power Quality Compensator (MF-UPQC) is optimal choice for attaining enhanced power quality features and it is a combined shunt or series compensator driven by common DC-link. This paper recommends the Adaptive Neuro-Fuzzy Intelligent Controller (ANFIS) based prediction technique for generation of optimal switching states to enhance performance of proposed MF-UPQC to compensate all voltage-current PQ imperfections. The performance of proposed MF-UPQC is verified by classical PI, Fuzzy and proposed ANFIS control functions by using MATLAB/SIMULINK tool and results are conferred with proper comparisons.

Interconnection of Hybrid Power System to Grid & Enhance Power Quality Features in DG System using Multilevel STATCOM

The distributed generation scheme with integration of renewable energy sources furnishes the feasible solution to acquire the stable power demand in grid-connected system under sudden load interruptions. Over the various compensation devices, the highly recognized multi-purpose Static Compensator is integrated to grid for attaining enhanced power quality features. A co-generation based grid-integrated renewable sources are used but, the output of these sources are maintained un-constant due to presence of variable source. In this paper, a novel current controller was developed to maintain output of co-generation system as constant and achieve the load demand continuously. But, this scheme has two major disadvantages, primary one is current controller prerequisites the traditional PI controller, which is controlled by intelligent based Fuzzy-Logic controller that is adopted. The second is, the regular 3-level voltage-source inverter is used in STATCOM which has square-wave output voltage requires high range of filter units, more common-mode voltage, high dv/dt stress, more switching losses, low efficiency, so on. These issues are counteracted by utilizing multilevel inverter with attractive modulation scheme. The performance evaluation of proposed Multilevel Inverter based STATCOM is verified by traditional PI and proposed Fuzzy-Logic current controller by using MATLAB/SIMULINK tool and results are conferred with comparisons.

Distributed Incremental Adaptive Filter Controlled Grid Interactive Residential Photovoltaic-Battery Based Microgrid for Rural Electrification

In this article, a distributed incremental adaptive filter (DIAF) controlled utility interfaced photovoltaic (PV) - battery microgrid system is presented with power quality features. From protection aspects, grid tied solar inverters are required to shut down at loss of the utility. However, the multi-purpose PV-battery system is developed to provide energy to the critical loads, even at loss of distribution network. The bidirectional controlled converter with a battery also mitigates the intermittency of a PV array under rapid variations in the weather. The extracted maximum power is supplied to the voltage source converter (VSC), which is transferred to the nonlinear loads and the utility. The distributed incremental adaptive filter is used to control the VSC with contribution of PV power and the battery. In addition, the DIAF control provides harmonics mitigation, load balancing and power factor improvement functionalities in order to deal with system connected with nonlinear loads. A PV power feed-forward (PVFF) term is incorporated in the current control for injection of active power to the utility as well as to improve the dynamic operation of residential PV-battery microgrid. The battery energy storage (BES) reduces the fuel bills and it is also utilized to provide smoothing attributes to the microgrid. The effectiveness of PV-battery microgrid is validated experimentally developed in the laboratory.

RETRACTED ARTICLE: Detection and classification of power quality disturbances or events by adaptive NFS classifier

In power distributed generation system, analysis of power quality is a major issue and hence it is essential to implement an efficient power quality system. To address and end this issue, the proposed work is mainly focused on the detection and classification of power quality disturbances or events by applying Hilbert–Huang transform (HHT) technique. HHT technique is a novel signal processing algorithm that comprises two processes. First is the empirical mode decomposition (EMD), which is an iterative process where N number of power quality signals are decomposed into intrinsic mode functions (IMFs). The second process, Hilbert transform, is applied to each IMF component. The advantage of using these two processes makes it an attractive power tool for quality event analysis. Once the IMF is obtained, it is easy to construct a time–frequency representation model. Then, the significant features are extracted from amplitude, phase and frequency instantly, which are the contour of IMFs of each power quality disturbance. For classification, adaptive neuro-fuzzy system (NFS) classifier is used. It is an intelligent system used for the combination of neural network and fuzzy logic. Power quality features are given as input to the NFS system. The experimental simulation is conducted in a MATLAB environment, and proposed HHT has higher efficiency compared to existing methods.

Improvement of 2.79-μm laser performance on laser diode side-pumped GYSGG/Er,Pr:GYSGG bonding rod with concave end-faces**Project supported by the National Natural Science Foundation of China (Grant Nos. 51872290, 51702322, and 51802307) and the National Key Research and Development Program of China (Grant No. 2016YFB1102301).

A comparative study on the laser performance between bonding and non-bonding Er,Pr:GYSGG rods side-pumped by 970-nm laser diodes (LDs) is conducted for the thermal lensing compensation. The analyses of the thermal distribution and thermal focal length show that the bonding rod possesses a high cooling efficiency and weak thermal lensing effect compared with the conventional Er,Pr:GYSGG rod. Moreover, the laser characteristics of maximum output power, slope efficiency, and laser beam quality of the bonding rod with concave end-faces operated at 2.79 μm are improved under the high-repetition-rate operation. A maximum output power of 13.96 W is achieved at 150-Hz and 200-μs pulse width, corresponding to a slope efficiency of 17.7% and an electrical-to-optical efficiency of 12.9%. All results suggest that the combination of thermal bonding and concave end-face is a suitable structure for thermal lensing compensation.

Towards an enhancement of power quality in the distribution system with the integration of BESS and FACTS device

Since a few years, a power quality issue becomes more critical on a power distribution system and profoundly influences on both technical and economic aspects. Grid stability is an essential constraint in present power system studies with the enhancement of power-quality features. During sudden interruptions, the battery energy storage system might be a better alternative to stabilise and meet the grid demand and/or it can store the energy during surplus power situation. The battery integrated compensator utilises the Synchronous Reference-Frame theory for power-quality enhancement & battery charge control rather than an additional controller. This paper presents a battery integrated distributed static compensator for power quality improvement and to meet grid-demand under sudden changes. The performance evaluation of proposed battery integrated distributed compensator is verified under both charging the discharging control modes, evaluated by using Matlab/Simulink platform, results are illustrated.

Interval Type-2 Fuzzy Based Photovoltaic Distributed Generation System with Enhanced Power Quality Feature

This paper presents an interval type-2 fuzzy logic (IT2FL) controlled single-phase enhanced power quality-based photovoltaic distributed generation (PVDG) system. The objective of this paper is to develop a PV inverter with the features of real power injection and power quality enhancement (PQE) capability such as reactive power compensation and grid current harmonics reduction at the point of common coupling (PCC). To overcome the problems of conventional controllers requiring intricate mathematical model, an IT2FL controller (IT2FLC) is proposed for the dc-link voltage control. A prototype model of the proposed system is developed in the laboratory and is tested with the help of dSPACE DS1104 platform. Finally, the performance of IT2FLC-based PVDG system is compared with a conventional PI-based PVDG system on the basis of both simulation and experimental results.

Effects of Voltage Dips on Robotic Grasping

This paper addresses the effects of electric power quality on robotic operations. A general overview is reported to highlight the main characteristics of electric power quality and it’s effects on a powered system by considering an end-user’s viewpoint. Then, the authors outline the influence of voltage dip effects by focusing on robotic grasping applications. A specific case study is reported, namely that of LARM Hand IV, a three-fingered robotic hand which has been designed and built at LARM in Cassino, Italy. A dedicated test rig has been developed and set up to generate predefined voltage dips. Experimental tests are carried out to evaluate the effects of different types of voltage dip on the grasping of objects.

The Study of Power Quality Analysis by S-transform

Power quality disturbance recognition is the basis of the power quality control. The application of S-transform (ST) and its different improved forms in power quality signal processing and feature extraction are summarized in this paper. After that, the existing disturbance recognition methods based on ST feature extraction are analysed. Finally, On the basis of summarizing the existing research, the prospect of future research is prospected.

Energy Management and Control for Grid Connected Hybrid Energy Storage System Under Different Operating Modes

DC-coupled microgrids are simple as they do not require any synchronization when integrating different distributed energy generations. However, the control and energy management strategy between the renewable energy sources and the energy storages under different operating modes is a challenging task. In this paper, a new energy management scheme is proposed for the grid connected hybrid energy storage with the battery and the supercapacitor under different operating modes. The main advantages of the proposed energy management scheme are effective power sharing between the different energy storage systems, faster dc link voltage regulation to generation and load disturbances, dynamic power sharing between the battery and the grid based on the battery state of charge, reduced rate of charge/discharge of battery current during steady state and transient power fluctuations, improved power quality features in ac grid and seamless mode transitions. The effectiveness of the proposed method is validated by both simulation and experimental studies.

Hybrid converter for electric vehicle battery charging with power quality features

The power factor correction converters for electric vehicle battery chargers result in higher conduction losses and reverse recovery losses when fed from low voltage supply line. To overcome the above problem, a hybrid switched capacitor Cuk converter based power factor correction converter is proposed which has high stepup gain and low-voltage stress across the switch. The converter offers a very significant efficiency improvement at low voltage supply line over the single-switch buck-boost converters (including fly-back, SEPIC and Cuk topologies) and conventional two-switch buck-boost cascaded converters. In this paper, the design and simulation of the proposed converter is carried out in continuous current mode (CCM). The modelling and simulation are done in Matlab-Simulink environment. The power quality indices like THDs (vTHD, iTHD), PF are evaluated to demonstrate the performance of the converter. The converter is evaluated both in steady state and transient conditions.

Hybrid converter for electric vehicle battery charging with power quality features

Hybrid converter for electric vehicle battery charging with power quality features

Features of Power Quality in Single-Phase Distributed Power Generation Using Adaptive Nature Vectorial Filter

This paper presents the new controller for voltage and frequency control (VFC) of two-winding single-phase induction generator. It provides coordinated control of battery energy storage system (BESS) and dump load during the mismatch of power between loads and generator using VFC loop. It provides protection against overcharging of BESS. For this purpose adaptive vectorial filter (AVF) is implemented to operate single-phase induction generator in standalone mode of operation for power quality features. The unique feature of this filtering technique is its simplicity and no other analogy filters are required to produce the reconstructed signal of fundamental frequency. This procedure uses the vectorial natures of the single-phase input signal, which is decomposed by shifting property in the α–β orientation frame in order to get the diverse harmonic constituents. The design and analysis of AVFs for the proposed system is carried out in order to find the required performance. The proposed control method is evaluated by simulations in MATLAB/Simulink followed by experimental validation in laboratory for signifying its capability to execute different harmonic constituents under an extremely distorted generator current. Apart from control method, design of generator with finite-element method and its electromagnetic properties are also discussed.

Variable learning adaptive gradient based control algorithm for voltage source converter in distributed generation

This study presents an adaptive control algorithm known as variable learning and adaptive gradient based least mean square for improving the power quality features in standalone distributed generation. Further, frequency and voltage are regulated to set reference value at the terminal of the self-excited single-phase induction generator running in isolated mode. The variable learning and gradient-based least mean square (VLGLMS) algorithm is insensitive to its gradient, step size and sensors noise unlike least mean square algorithm whose convergence performance is influenced by the step-size parameter. In this study, VLGLMS is utilised to compute the active and reactive weights of fundamental load current for estimation of the reference source current. The sinusoidal reference current estimation is followed by generation of gate pulses for operating the DSTATCOM for improving the power quality features of single-phase induction generator based distributed power generation system. A prototype model is developed using MATLAB SIMULINK and tested in the laboratory under linear and non-linear loads. Based on implementation, the performance of control algorithm is validated and obtained results are found satisfactory.

A Novel M-SEPIC DC-DC Converter for BLDC Pumping System with Active PFC using ANFIS Controller

An exigent consumer related concerns confronted due to utilization of massive front-end AC-DC rectifier in a grid-tied BLDC pumping system. Harmonic distortions are acquired, which prompts the disruption of power quality at utility grid system due to AC-DC conversion. Several factors for enhancing power-quality concerns are ameliorate the grid power-factor along with reduction of harmonic distortions, tightened regulation of DC output voltage. In this way, the DC-DC boost converter plays a unique role; operated in Continuous Conduction Mode. Based on summarizing advantages & disadvantages of classical DC-DC converters, a single switch high voltage gain M-SEPIC DC-DC converter is more suggestive for water pumping system due to non-existence of coupled inductors, low switching loss, low di/dt stress, high efficiency, compact structure, low cost, etc. This work proposes the novel M-SEPIC DC-DC converter fed brushless-DC motor drive is controlled by voltage source inverter and powered by single-phase grid system with improved power-quality features. Moreover, Adaptive Neuro-Fuzzy Inference System is recommended for prediction of optimal switching states to amplify the BLDC motor speed and torque-ripple depreciation. The effectiveness of the proposed scheme is validated under constant speed situations by real-time operating conditions which are evaluated by Matlab /Simulink tool; and simulation results are conferred with attractive comparisons.

Power Quality Feature Modelling of Waveform Disturbances for Distribution System Diagnosis

This paper presents a Power Quality (PQ) modelling and filtering processes for the distribution system disturbance recognition learning. typical PQ waveforms with mathematical applications and gathered field data are applied to our models. The process has modules to obtain the waveforms of incipient failures or abnormal operations, trouble condition waveforms in the distribution system through feature extraction and trigger condition techniques. In this regard, we found that proposed extraction criteria of determination rules can interact suitably with our parameter update method to detect and containing the waveforms. Therefore, the recurring analysis can classify the event conditions and ensures disturbance and fault recognitions which containing the waveform information.

Bidirectional converter for electric vehicle battery charging with power quality features

Bidirectional converter for electric vehicle battery charging with power quality features

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8–10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

Isolated Power Generation System Using Permanent Magnet Synchronous Generator with Improved Power Quality

This paper deals wind energy based power generation system using Permanent Magnet Synchronous Generator (PMSG). It is controlled using advanced enhanced phase-lock loop for power quality features using distribution static compensator to eliminate the harmonics and to provide KVAR compensation as well as load balancing. It also manages rated potential at the point of common interface under linear and non-linear loads. In order to have better efficiency and reliable operation of PMSG driven by wind turbine, it is necessary to analyze the governing equation of wind based turbine and PMSG under fixed and variable wind speed. For handling power quality problems, power electronics based shunt connected custom power device is used in three wire system. The simulations in MATLAB/Simulink environment have been carried out in order to demonstrate this model and control approach used for the power quality enhancement. The performance results show the adequate performance of PMSG based power generation system and control algorithm.

Performance Factors of the Photovoltaic System: A Review

Photovoltaic (PV) technology is one of the clean sustainable energy technology which sourced from the sun. However, there are many issues that can potentially degrade the system. This paper extensively discusses on the hybrid system power generation for the photovoltaic (PV) system. In addition, this paper also reviews the factor that affecting the photovoltaic system performance including the types of PV cell, the effect of ambient condition, system components, and the power quality characteristics. The performance of the monocrystalline type greater than the polycrystalline type around 5-7%. The usage of an inverter gives an impact with 8-20% of total energy losses. Finally, this paper summarises the future research work needed to overcome the drawback of the available photovoltaic systems.