International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Issue: 07 | July -2017
p-ISSN: 2395-0072
www.irjet.net
DVR AND ITS VARIOUS CONTROL SCHEMES: A SURVEY Shruti Agrawal1, Lumesh Kumar Sahu2 1M.tech
Scholar, Dept. of Electrical Engineering, Kalinga University, Raipur Professor, Dept. Of Electrical Engineering, Kalinga University, Raipur ---------------------------------------------------------------------***--------------------------------------------------------------------2Asst.
Abstract - One of the major concerns in industries is the quality of the power in main line. This has become more important with the inclusion of new advanced power quality devices which are sensitive for small changes in the quality. Main cause of the power quality problem is poor standard voltage, current or frequency which may cause the failure of the hardware. Power sagging and power swellings are the two main issues which are most prevalent in industries. Custom power devices are one of the solutions of this problem. Dynamic voltage restorer (DVR) is one of such custom power device which is used most frequently in the power distribution. This paper is an attempt to present a review work on the DVR technology along with the various applications proposed in the past.
Practically the magnitude of the voltage during the sag interval has more influence than the duration of the sag on the system. It was observed that the voltage sag occurs in the industries are generally within the 40% limit of the nominal voltage. Sagging of the voltage may cause the damage of million dollar which include the breakdown, production lost etc [2] [3]. Generally the main cause of the voltage sag is fault in short circuit, starting the motor, energizing the motor via transformer. This fault generally increases the current in the line which causes voltage sag on the line.
Key Words: DVR, Voltage Sag, Voltage Swell, Filter, Power Quality, VSC. 1. INTRODUCTION The performance of many industrial applications like in advanced control, automation, precise manufacturing application, power quality play very important role. Most of the above application requires precise shape of the sine wave constant frequency and symmetrical voltage along with the constant root mean square value (RMS). It is therefore essential to eliminate such type of disturbances. Some of the common power quality degradations are voltage sag, voltage swell, phase shift, harmonics and transients [1] [2]. Among all type of power quality problems, voltage sag is considered as the most severe problem. It is due to the facts that the sensitive loads are very susceptible to even smaller changes in the voltage. Reduction in the voltage magnitude for a small interval of time is called voltage sag. The magnitude of the voltage suddenly drops to the lower value and comes back to the original value after approx. 150 mili-seconds. Though such kind of disturbance last for short duration even if it causes serious problems for a large rand of equipments [1][3]. Two very important characteristics which is related with the voltage sagi. ii.
Figure 1 Basic Configuration of DVR For most of the sensitive equipment, voltage correction device is the only cot effective solution. Different type of approach and methods are available to fight this type of the voltage dip problem. One of the advanced approach is to apply the voltage source converter in series between the sensitive load and supply system. This type of device is generally termed as the dynamic voltage restorer (DVR).
Duration of the sag. Magnitude of the voltage during the sag interval.
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