An on-line distributed power quality monitoring system based on

An on-line distributed power quality monitoring systembased on internet and labVIEW

1Preethi Loganayaki.V,

2Keerthiga.S.,

3Sundar Raj.S,

1P.G student,

2P.G student,

3Asst professor,

Department of Electrical and Electronics EngineeringInfant Jesus college of Engineering,Tirunelveli.

[email protected],

[email protected],

[email protected]

Abstract— Poor power qualities affect functioning of utilities, different industrialunits, productions, and customer services another system performance and operatingcosts. There is an ever increasing need for power quality monitoring systems due tothe growing number of sources of disturbances in AC power systems. Monitoring ofpower quality is essential to maintain proper functioning of utilities, customer servicesand equipments. Online power quality monitoring system is the development of theInternet as a vehicle for the use of electronic information and communicationtechnologies to provide and support power quality monitoring when distanceseparates the different sites and data centre. Current power quality monitoringapplications are usually developed for remote power quality inspecting and analyzing.It is possible for engineers to diagnose the faults and evaluate power quality at thedata centre via Internet. On other hand, we also carried out the monitoring of powerquality with the help of virtual instrument using labVIEW software.

Keywords-Power Quality Monitoring system, Internet, Power Quality Meter, labVIEW,Virtual Instrument.

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I.INTRODUCTION

The term power quality is appliedto a wide variety of electromagneticphenomena on the power system. Theincreasing application of electronicequipment and distributed generation hasheightened the interest in power quality inRecent years, and this has beenaccompanied by the development of aspecial terminology to describe thephenomena. Power quality monitoring isthe process of gathering some data aboutvoltages and currents; transporting thatdata to somewhere it will be useful; andconverting that data into decision-makinginformation. Any power problemmanifest in voltage, current ormisoperation of customer equipment.

Power quality events have beenproposed using on-line monitoring. This

technique involves the monitoring of powerquality with the assistance of power qualitymeters, and also with the help of clientcomputers, web servers and power qualitydatabase and communication networks. Inthe earlier stages different instruments wereused for monitoring different power qualityproblems.

Transients. Short duration voltage

variation. Long duration voltage

variation. Voltage Interruption. Voltage imbalance.

International Journal of Scientific & Engineering Research, Volume 4, Issue 5, May-2013 ISSN 2229-5518

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. Power quality events have beenproposed using on-line monitoring[1].This technique involves themonitoring of power quality with theassistance of power quality meters, andalso with the help of client computers,web servers and power quality databaseand communication networks.In the earlier stages different instruments

were used for monitoring different powerquality problems [5].A proposed power system for power

quality monitoring with the help of virtualinstrument using labVIEW software [2].Virtual instrument with a wealth of

software, hardware, simple structure,highly intelligent, and othercharacteristics [3]. In order to evaluatepower quality more accurately, presents athree-layer distributed online powerquality monitoring system (PQMS),whichuses the General Packet RadioService(GPRS) wireless network as itscommunication channel. This PQMSconsists of three parts; the power qualitymonitor(PQM),the monitoringsoftware(MS) in upper computer and theweb platform(WP).The PQM which isdesigned on the structure of DSP(DigitalSignal Processor)&CPLD(ComplexProgrammable Logic Device) ensures thereal-time and precise monitoring. Thenthe MS collects and analyzers themonitoring data. At the same time, GPRSnetwork provides the communicationchannel for PQM and smother WPprovides the monitoring data and theanalysis results through internet, andsupervisors can monitor and manage thepower quality from a long distance [7].Due to the great progress made on theInternet, the World Wide Web hasbecome a convenient way to accessinformation on the net. As the WWW hasmatured, three major classes web HTML“language” combined with HTTPapplication protocol provided amechanism for the remote viewing ofsuch documentation.DSP-based power quality monitoring

instrument is proposed for real-timedisturbance recognition and sourcedetection.The deregulation and restructuring of

the electricity industry is changing howutilities and customers approach powerquality monitoring. Drantez-BMI Ltdintroduced the first PQ monitor in themid-1970s which was a microprocessorbased monitor analyzer without graphicdisplay. In the last few years, the rapidadvances in semiconductor technologyhave increased the performance andreduced the cost for PQ monitors. Thereare various types of PQ monitoringinstruments available in the marketdepending on their functions in whichthey are considered as revenue meter,digital fault recorder and permanentlyinstalled PQ monitor .All theseinstruments come with software andcommunication capabilities for datacollection, data processing and resultpresentation. In terms of architectureand instruments are based on either PCor DSP with advanced commercialsoftware like Matlab, LabVIEW orgeneral programming languages such asC++. Examples of DSP based PQmonitoring instruments which arecommercially available are the reliablepower meter and PowerGuide4400.However, these instruments canonly record waveforms and use asoftware for collecting data and viewingmonitoring results including voltageprofiles and harmonic distortioninformation.

To Implement an intelligent PQmonitoring instrument which canprocess raw measurement data andprovide useful information for PQdiagnosis, a new DSP-based PQmonitoring instrument is proposed.


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II.RECOMMENDED IEEESTANDARDS

IEEE Standards documents aredeveloped within the Technical Committeesof the IEEE Societies and the StandardsCoordinating Committees of the IEEEStandards Board. Members of thecommittees serve voluntarily and withoutcompensation. They are not necessarilymembers of an Institute. The standardsdeveloped within IEEE represent aconsensus of the broad expertise on thesubject within the Institute as well as thoseactivities outside of IEEE that haveexpressed an interest in participating in thedevelopment of the standard.

IEEE Standards documents may involvethe use of patented technology. Theirapproval by the Institute of Electrical andElectronics Engineers does not mean thatusing such technology for the purpose ofconforming to such standards isauthorized by the patent owner. It is theobligation of the user of such technologyto obtain all necessary permissions.

IEEE std 141-1993,IEEErecommended practice for Electricpower Distribution for Industrialplants.

IEEE std 142-1991,IEEErecommended practice forgrounding of Industrial andcommercial power system

IEEE std 241-1991,IEEErecommended practice for Electricpower system in commercialbuildings.

IEC 61000 series, Electromagneticcompatibility. III.VARIOUS ON-LINE POWERQUALITY MONITORING TECHNIQUES

III.VARIOUS POWER QUALITYMONITORING TECHNIQUES

A.POWER QUALITY MONITORINGOVER INTERNET

Power quality monitoring is a easy-to-use technology, there tends to be a webapplication between the different sites anddata center that it can simply be madeavailable to engineers who will easily usethe power quality monitoring systems [2].With the advancement of information andcommunication technology, Internetconnecting millions of hosts worldwide hasbeen getting more and more popular inpower systems. Computer networks havemade it possible to share electronic data. Inthis paper, we developed an Internet-basedpower quality monitoring system for remotepower quality inspecting and analyzing. Themajor features of the system are describedas following:

1.Provides GPS-based power qualitymeters (PQM) for synchronouslysampling data on the remote site;2.Sets up site data manager clientsoftware that will manage the nodes thatwill collect, store and compress the powerquality data produced by the PQMs;3.Provides the efficient and convenientmethods for the different sites and datacentre to communicate with each otherand allows the different sites to send theirdata through the Internet;4.Provides computer-based investigatorclient software that provide relatively easyand fast access to large databases and thatpermit the application of powerfulstatistical methods for analyzing anddisplaying those data.

GPS technology to synchronize samplingdata in the power quality meter, foundationof network platforms with Win2003Server/IIS, application of power qualitydatabase using Microsoft SQL, site clientsoftware to collect, store and compress thepower quality data from the power qualitymeters and investigator client software to


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analyze and calculate relevant powerquality parameters. This system canprovide assurance to power systemsecurity.

SYSTEM ARCHITECTURE

While both the PQMs and thenetwork interface to the instrument mightreside in the remote site, nothing preventsthese instruments from being dispersedgeographically. For example, theinstruments might be located in theremote site while the interfacemechanisms are located at the data center.In addition; this approach to systemdesign makes it possiblefor the PQMs to be monitored by thedatacenter, thereby allowing the remote siteto interact with the data centre. It is thisdistributed web-like model of power qualitymonitoring system interactions in which“clients” and “servers” dynamicallyconfederate for a period of time and thendisassociate from one another. Taking thisstep lays the necessary foundation forInternet-based power qualitymonitoring system.

Fig.1.An Internet Based Power Qualitymonitoring System.

PQM (Power Quality Monitoring)

The power quality monitoring system isa collection of technologies including aweb server, computers, communicationnetworks, and specialized PQMs. Themost common feature of a power qualitymonitoring system is the ability totransmit high-quality data across acommunication line. Critical functionsinclude data acquisition and downloading,data processing, and delivery of resultsand reports. Traditionally, separatecomputers have handled these functions,but new technology is enabling them to behandled either from a central station orfrom stations throughout a Monitoringnetwork. The system topology ispresented in Fig.1. The power qualitymonitoring system is structured using aset of basic components. They includePQMs , client computers , web server andpower quality database, andcommunication networks.The PQMs are connected to the power

system via current and potentialtransformers. These instrumentsconstantly record the voltage and currentwaveforms at a resolution of up to 1024samples per cycle. This data iscompressed on board using the wavelet-based data compression technology. Thecompressed files are transferred site datamanager client Software. The site datamanager client software stores the datacollected from the PQMs and responds torequests from client workstations runningInvestigator software.

When an engineer using the Investigatorsoftware wishes to analyze the datacollected by the PQMs from a certain timeframe, the investigator client softwaredecompresses the requested data, performsthe necessary mathematical calculations todisplay the electrical parameters requestedby the client and then arranges andconfigures the data to be displayed on thespecific screen used by the client.


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Power Quality Monitor

The PQM is an accurate electronicpower meter capable of sampling voltageand current waveforms. PQM representsmechanisms for acquiring power qualitydata, delivering data to site data managerclient software. All the PQMs areconnected to the local network and byusing unique time synchronization basedon GPS. In this way, it was possible tomonitor all the information from differentlocation on the same graph and the sametime base.

For real time power quality measurement,voltages and currents of all measuringnodes must be measured simultaneously.The pulse of GPS is used assynchronization signal of the measurementsystem. PQMs are partitioned into twolayers. The first layer is the physical device;the second layer is a software “proxy” thatrepresents the device in another piece ofhardware. In either case the device presentsan established interface that “wraps” thecomponents actually used to provide thefunctionality. In addition, the technologiesused to deliver the requested services maybe transparent.

B.USING GPRS

In order to evaluate power quality moreaccurately, presents a three-layerdistributed online power qualitymonitoring system (PQMS), which usesthe General Packet Radio Service(GPRS)wireless network as its communicationchannel.

This PQMS consists of three parts; thepower quality monitor(PQM),themonitoring software(MS) in uppercomputer and the web platform(WP).ThePQM which is designed on the structure ofDSP(Digital SignalProcessor)&CPLD(Complex ProgrammableLogic Device) ensures the real-time andprecise monitoring Then the MS collectsand analyzers the monitoring data. At the

same time,GPRS network provides thecommunication channel for PQM and MS.

Fig.2.Power quality monitoring usingGPRS technique.

The WP provides the monitoring data andthe analysis results through internet, andsupervisors can monitor and manage thepower quality from a long distance.

C.USING WEB BASEDTECHNOLOGY:

The HTML “language” combinedwith HTTP application protocol provideda mechanism for the remote viewing ofsuch documentation. Lack of interactivitysoon appeared via HTML form elements(CGI-The common gateway interface)isused. In recent year, other technologieshave emerged on the Internet: the ActiveServer Pages (ASP) and Java. Like theCGI, ASP is also executed on the WebServer and sends the results to the client inHTML document format. But it providesmore powerful functions and an easier

interface than that of CGI.


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Fig.3.Working of Active Server pages.

D.Monitoring power quality by virtualinstrument using labVIEW:

Now-a-days much works are done onReal-Time power quality monitoring, stillmuch improvement is required for presentday problems. We are in need of anintelligent system with up-to-date andappropriate software that works smoothlywith appropriate hardware to form acompact single station/system for powerquality monitoring and controllingwithout the use of different devices fromdifferent vendors.

The solution for these problems isobtained by designing and implementinga simple power quality monitoringsystem. Its development is based onsoftware using graphical programming towork along with appropriate hardware toform a compact single station for powerquality monitoring without the use ofdifferent devices from different vendors.This work addresses especially on themeasurement of the signals to detect anydisturbances or distortions of the voltagepower line, and giving priority to theneeds of the small scale industries andalso for the domestic consumers.

Different virtual instruments (VIs) wereimplemented using graphical programminglanguage (virtual instruments) by way ofsoftware development and manipulation.

The simulations VIs are used to generatevoltage waveforms .The interfacingdevices are send to connect the softwareand hardware through serialcommunication with someadditional/necessary hardware. The mainaim of this paper has been to develop animproved and intelligent PQM system byusing software along with necessaryhardware’s and to test a prototype systemfor real time PQM. The results show asuccess in this object.The software is developed using

graphical programming language calledLabVIEW which is the trade mark of theNational Instruments (NI), Austin, Texas,USA.The full form of LabVIEW is laboratoryvirtual instrument engineering workbenchand is a graphical development environmentwhich can be used to conduct scalable tests,measurements, and control applications, inaddition to the ability to interface real-worldsignals and analyze data for meaningfulinformation .[9 ],[10].

Fig.4.Main elements of PQM system.

Virtual Instruments:Virtual instrument refers to organically

integrating the computer resources of theuniversal application with the hardwaredevices through applied


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programs.Consequently, the powerfulcomputing capability is combined withthe devices capacity of measurement andcontrol. The cost an volume of hardwaredevices had been greatly narrowed. Userscan operate this computer through thefriendly graphical interface like operatinga single instrument defined and designedby users themselves.Advantages-Virtual Instruments:

Compared virtual instruments withtraditional instruments, virtual instrumentshave specific advantages as follows:1) They have enriched and enhanced thefunction of traditional instruments.2) Equipment from the user’s owndefinition.3) To highlight the concept software isinstrument.4) Open industrial standard.5) To facilitate the complex testingsystems.INTRODUCTION OF LabVIEWSOFTWARE:

LabVIEW is referred to as LaboratoryVirtual Instrument EngineeringWorkbench, is developed by NationalInstruments a data-driven programminglanguage substitute text programminglanguage to create the development toolsof application, this program emphasizeand that the process of signal processing,simple programming and debuggingeasier.

Virtual instrument developmentplatform LabVIEW has the followingcharacteristics.1) Graphical equipment programmingenvironment.2) Feature-rich library.3) Flexible means of procedure debugging.4) Open development platform.5) Network.

Fig.5.Front panel of LabVIEW program.

LabVIEW programmes are called virtualinstruments (VI), because they have thelook and feel of physical instruments. It isdivided into front panel and blockdiagram. Front panel is the user interfaceof the Inbuilt with controls and indicators.Block diagram is the VI’s source code,constructed in LabVIEW graphicalprogramming language and it is the actualexecutable program. Different virtualinstruments are implemented using the NILabVIEW graphical programminglanguage.


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Fig.6.Block diagram of LabVIEWprogram.

Fig.7.voltage signal in time domain.

Fig.8.voltage distortion.

Fig.9.voltage transients.

Fig.10.voltage sag.

Fig.11.Interruption of power supply.

CONCLUSION

In this paper we discussed about thevarious techniques available, to monitorthe power quality issues and also, theanalysis is carried out and we find that theon-line monitoring technique support


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remote power quality inspecting andanalyzing across global wide areanetworks. On other hand, the advantagesof LabVIEW technique is, numerouslarge-scale experiments show the richadvantages of this system with easymanagement, short term for development,good cost performance, along with theother features as convenient softwareupdating stable operation, completefunctioning and high automation, etc.

REFERENCES

[1] MingZhang and Kaicheng Li,”APower Quality Monitoring System overthe Internet,”(ICISE2009).

[2]Shahedul Haque Laskar and MohibullahMuhammad,”Power Quality Monitoring byVirtual Instrumentation Using labVIEW,”International Universities PowerEngineering Conference.

[3] Yang Huping and Bi Zhipeng,”ThePower Quality monitoring System Basedon Virtual Instrument,”World Congresson Software Engineering.

[4] Richard P.Bingham,”MeasurementInstrument for Power QualityMonitoring,”2008 IEEE.

[5] Rong-Ceng Leou,Ya-Chin Chang andJen-Hag Teng,”A Web Based powerQuality Monitoring System,”2001 IEEE.

[6]Xie Yi,Ouyang Sen,XiaChengjun,”Design and Realisation of anOnline Power Quality Monitoring SystemBased on GPRS.

[7] LabVIEW user manual 7.1

[8] LabVIEW user manual 8.5.1


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An on-line distributed power quality monitoring system based on