Dynamic Voltage Restorer (DVR)

SUMMARY: Power quality is one of major concerns in the present era. It has become important, especially, with the introduction of sophisticated(sensitive) devices, whose performance is very sensitive to the quality of power supply. Power quality problem is an occurrence manif

Project Title

Dynamic Voltage Restorer (DVR)

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

SUMMARY:

Power quality is one of major concerns in the present era. It has become important, especially, with the introduction of sophisticated(sensitive) devices, whose performance is very sensitive to the quality of power supply. Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure of end use equipment. One of the major problems dealt here is the power sag.

1. Voltage Sags 2. Phase Outages 3. Voltage Interruptions 4. Transients due to Lighting loads, capacitor switching, non-linear loads, etc. 5. Harmonics 6. Dips or Surges 7. Burnouts

Therefore, it is necessary to recognize and compensate all types of disturbances at an earliest time to ensure normal and efficient operation of the power system. To solve these problems, many types of power devices are used. At the present time, one of those devices, Dynamic Voltage Restorer (DVR) is the most efficient and effective device used in power distribution systems.

Project Objectives

Objectives:

The author of research paper "Thangellamudi Devaraju" has done simulations of this

technique on Simulink for three phase system but hasn't yet implemented it on hardware.

Our goals in this project were:

• To do the simulations for single phase system.
• To implement this technique on hardware for the very fast time and see its limitations.

Project Implementation Method

Implementation:

We successfully implemented this technique on MATLAB software in the form of simulation. Then next challenge was to implement this technique on hardware in order to validate the results obtained in simulations. During implementation of this technique on hardware we faced some issues. Some of them were resolved but issues require more in order to make this device available for full practical use.

Then the biggest challenge was to design a freewheeling circuit for our system. As transformer used at load end to step up the voltage had leakage inductance and also to account the inductive loads. Due to chopping of sine wave inductor produces spikes in both positive and negative cycle of supply voltage.

The idea was to allow the negative spikes in voltage waveform during positive half cycle to pass through lower IGBT as above and positive spikes in voltage waveform during negative half cycle to pass through upper IGBT above. Upper IGBT would conduct from drain to source for positive spikes of voltage while lower IGBT would conduct from source to drain for negative spikes of voltage.

There are some advantages and dis-advantages associated with each technique. As in case of IGBTs voltage spikes of larger values could turn on those IGBTs without gate signal hence may sometimes result in severe harm to whole circuit but driver circuit is not too much complex as we have to turn on IGBT by applying gate signal but to turn IGBT doesn’t require any explicit supply rather logic zero on gate terminal. As there is inbuilt diode in IGBT package so extra circuitry is required to avoid conduction by that diode.

Phase #1:

Hardware Implementation:

1 Components Selection

1.1 AC-AC matrix converter

1.2 Step up Transformer

1.3 Filter Design

1.4 Op-to-coupler and Gate Driver

1.5 ADC Circuit

1.6 Designing Components for Voltage Sensor

1.7 Relay Controlled Switch

1.8 Load

Phase #2:

Programming and Software:

2.1 Software

2.2 LCD interfacing with Micro-controller

2.3 ADC and Conversion to Actual Load Voltage

2.4 PI Controller

2.5 PWM Generation

Benefits of the Project

PROBLEMS AND BENEFITS:

The problem of voltage sags and swells and its severe impact on sensitive loads is well known.

• Voltage sags
• swells
•  flicker
• voltage notch,
• harmonic distortions,
•  transients and momentary interruptions
• Phase Outages
• Voltage Interruptions
• Transients due to Lighting loads,
• capacitor switching,
• non-linear loads

Using DVR we can removed all above problems and, save power and devices safety.

Technical Details of Final Deliverable

Deliverable Propitious choice of DVR:

          There are numerous reasons why DVR is preferred over other devices:

1. Although, SVC predominates the DVR but the latter is still preferred because the SVC has no ability to control active power flow.
2. DVR is less expensive compared to the UPS.
3. UPS also needs high level of maintenance because it has problem of battery leak and have to be replace as often as five years.
4. DVR has a relatively higher energy capacity and costs less compared to SMES device.
5. DVR is smaller in size and costs less compared to DSTATCOM
6. DVR is power efficient device compared to the UPS
7. DVR is very fast and efficient device as compare to other device.
8. The DVR handles both balanced and unbalanced situations without any difficulties.
9. The energy capacity of the DVR is higher than that of the UPS which has the same power rating.
10. the size of a DVR is smaller than that of the DSTATCOM.
11. Furthermore, it is the cheapest in comparison with the UPS and the DSTATCOM

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Energy

Other Industries

Others , Security

Core Technology

Internet of Things (IoT)

Other Technologies

Shared Economy, Others, Big Data

Sustainable Development Goals

Affordable and Clean Energy, Industry, Innovation and Infrastructure, Responsible Consumption and Production, Partnerships to achieve the Goal

Required Resources

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