Dvr

Points To Be Discussed

Introduction  What is DVR?  Need of DVR  Block Diagram of DVR  Principle of Operation  Installation of DVR  Simulation of DVR  Advantages of DVR over others  Benefits of DVR  Industrial Application of DVR  Conclusion  References 

INTRODUCTION

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Power Quality-The term is used to describe electric Power that drives an electrical load and the load's ability to function properly with that electric power. Voltage Sag-The short duration reduction in nominal voltage magnitude by 10-90% from half a cycle to one minute is called voltage sag. Voltage Swell-The sudden increase in supply voltage by 10-80% from 10 ms to 1 minute CPD-Hingorani was the first to propose FACTs controllers for improving power quality.He termed them as Custom Power Devices(CPD).Based on the VSC they are of 3 types (i)-Shunt connected D-statcom(Distribution static Compensator) (ii)-Series connected DVR(Dynamic Voltage Restorer) (iii)-combined Series & shunt connected UPQC(Unified Power Quality Conditioner)

What is DVR????? 

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A Dynamic Voltage Restorer (DVR) is a series connected solid state device that injects voltage into the system in order to regulate the load side voltage. The first DVR was installed in North America in 1996, a 12.47 kV system located in Anderson, South Carolina It is normally installed in a distribution system between the supply and the critical load feeder It controls one of the most important Power Quality issues called Voltage sag which have a bad influence on sensitive loads having semiconductors fabrication. Primary function of DVR is to minimise the voltage sags on lines that affect the sensitive equipment

Need Of DVR:

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If voltage sag is not controlled it will have severe impact on sensitive load. The DVR acts as a filter between the distribution line & the feeder to receive the clean power

Block Diagram Of DVR 1-Booster Transformer 2-Harmonic Filter 3-Voltage Source Converter (i)-Switching Devices (MOSFET,GTO,IGBT,IGCT) (ii)-Storage Devices(Batteries & Ultracapacitors) 4-Control& Protection System

Principle of Operation

Installation Of DVR Platform Mounted DVR(Demonstration):-

Platform Mounted DVR(contd…)

Interconnection Equipment

Simulation of DVR 

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In order to show the performance of the DVR in voltage sags and swells mitigation, a simple distribution network is simulated using MATLAB But for large systems the modelling &simulation of DVR is done using PSCAD(Power System Computer Aided Design) & EMTDC(Electromagnetic Transients including DC)

Advantages of DVR over others Each of Custom Power devices has its own benefits and limitations. Dynamic Voltage Restorer (DVR) is one of the most effective type of these devices. There are numerous reasons why the DVR is preferred over the others. Some of them are explained below. The SVC(Service Voltage Converter) pre-dates the DVR, but the DVR is still preferred because the SVC has no ability to control active power flow DVR has a higher energy capacity and lower costs compared to the SMES(SuperConducting Magnet Energy Storage)device

DVR is smaller in size and costs less compared to the DSTATCOM. DVR is observed to be very insensitive to the fault level but sensitive to the system load level. In terms of minimum apparent power injection or size of the coupling transformer, the performance of a DVR is found to be superio to a DSTATCOM

Benefits of DVR 

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Reduce losses associated with irregularities in the production process resulting from power disturbances. DVR plays a key role in ensuring the smooth functioning of sensitive equipments. DVRs can also be used to tackle the problem of harmonics caused by non-linear load machinery in manufacturing facilities. The insulation wear on transformers, motors and drivers caused by power irregularities can also be reduced by DVR.

Industrial Applications of DVR Utilities (transmission and distribution companies)  Process industries (semiconductor plants, paper mills, plastic manufacturers)  Automotive manufacturers(Automobile Industries)  Electronics (consumer electronic and computer manufacturers)  Chemical plants(nitrogen Plants like Bhusan,Hydrogen Plants like Indore),Steel Plants & So on 

Conclusion

The cost-effectiveness of DVR is likely to highlight the need and usefulness of sag-free transmission, as the requirements for high-quality power increase. Deregulatio in the industry and the increasing number of power producers makes it all the more important to keep the customers satisfied at any cost. At this the presence of DVR in the marketplace is bound to be noticed and it is likely to pick up even more in the near future.

References

http://www.frost.com/prod/servlet/frost-home  http://www.pdfcoke.com  http://www.netfirms.com 

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N. G. Hingorani, "Introducing CUSTOM POWER"IEEE Spectrum June 1995.

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