DESIGN AND CONSTRUCTION A THREE PHASE AUTOMATIC VOLTAGE STABILIZER
This project is titled the design and construction of a three phase Voltage Stabilizer. It is designed to meet up with the AC voltage safety, stability and accuracy demand in industries and in homes. Three phase automatic Voltage stabilizers are useful in devices or load that have three phase such as computer Power supplies, alternators and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution system, three phase voltage regulators may be installed at a substation or along distribution lines so that all customers receive steady voltage independent of how much power is drawn from the line.Three phase stabilizer is more versatile and is the most commonly used type for use with three phase loads. This basically consists of 3 single phase units of 1/3rd capacity each. In this type, the output voltage on all three phases is equal even if the input voltage and the loads connected on the three phases are entirely different (unbalanced). An AC Automatic voltagestabilizer is designed to automatically maintain a constant AC voltage level. An AC Voltage Stabilizer may be a simple “feed-forward” design or may include negative feedback control loops. It makes use an electromechanical mechanism, and other electronic components. It is used to regulate three different AC voltages. The aim of this project is to design a three phase stabilizer which can stabilize an AC input voltage of 160-250V to give three output AC output voltages of 220V at 50Hz automatically. The automatic feature can be achieved by the electronics devices used such voltage comparator IC, electro-magnetic device (relay), three phase transformer and other electronics devices.
TABLE OF CONTENTS
TABLE OF CONTENTS
LIST OF TABLE
AIM AND OBJECTIVE OF THE PROJECTTRANSFORMER CONFIGURATIONSIGNIFICANCE OF THE PROJECTSCOPE OF THE PROJECTLIMITATION OF THE PROJECTPROJECT ORGANISATION
2.0 LITERATURE REVIEW
HISTORY OF THE PROJECTTHE POWER SUPPLYTHEORY OF TRANSFORMEROPERATION OF THE TRANSFORMERVOLTAGE TRANSFORMATION RATIONTRANSFORMER LOSSES
3.0 CONSTRUCTION OF THE SYSTEM
SYSTEM CIRCUIT DIAGRAMCIRCUIT OPERATIONMODE OF OPERATIONCONTRUCTION PROCEDUREDESIGN FO THE TRANSFORMER PROPERSUMMARY OF THE SPECIFICATION OF TRANSISFORMERSHORT CIRCUIT TESTTESTING OF THE TRANSFORMEROPEN CIRCUIT TESTDESCRIPTION OF TRANSFORMER USED.
4.0 RESULT ANALYSIS
TESTING ANALYSISSYSTEM POWER-UPINSTALLATION OF THE SYSTEMUNPACKING AND INSPECTIONTROUBLESHOOTING METHOD OF THREE PHASE AUTOMATIC VOLTAGE REGULATOR.MAINTENANCE OF THE SYSTEM
There are many fundamental different types of stabilizers in use some of which are electron mechanically tap changer, solid state tap changer etc. voltage, stabilizer came into being not by normal design and plain, but as a means of solving electrical “Crisis” situation. This crisis situation does rarely occur in developed countries of the world such as Britain, American, Germany etc, why?
Their system of generation, transmission and distribution of electricity is such that a devoid of variation of fluctuation in the supplied voltage. Now, by the definition given by K.G Jackson and R. Feinberg, a voltage stabilizer is a piece device incorporated in a circuit to maintain a constant output voltage from a poorly generated power supply. A voltage stabilizer like any other piece of equipment is a combination of many electrical and like any other piece of equipment is a combination of many electrical and electronic and circuit with the aim of getting the assemble to perform a specified desired task or the function.
Referring the topic at hand, which is three phase automatic three phase voltage stabilizer which is the type of automatic voltage stabilizer with three phase output. This three phase AVR is fitted with isolation transformers in a delta-star configuration. This provides and clean, isolated supply to the load with a ‘new’ neutral connection. The AVR is made up from three identical single phase regulator units. Each of these monitors its own output voltage and adjusts for variations in mains supply voltage so as to maintain an output voltage within close limits.
When the AVS function is fitted, the outputs from the regulator are connected through a contactor to the load. The contactor is controlled by a three phase Automatic Voltage Switcher PCB which monitors the AVR outputs. This connects the load only when all the phase voltages are within acceptable limits. There is a delay function in the AVS to prevent frequent switching of the load.
A change-over switch is provided to by-pass the AVR in the event of needing to perform maintenance on the AVR.
An output circuit breaker is provided to protect the AVR from overload current and short circuit loads. Fans and thermal switches provide temperature control and protection. Filters, suppressors and fuse provide electrical protection.
1.2 AIM AND OBJECTIVE OF THE PROJECT
Most electrical appliance this day highly sophisticated to the entreated that cases of intermitted or regular power outages, under voltages or over voltages are not tolerate in them. The initial outlay and the cost or repair (in case of damage) are so economical that is means of maintain steady or regulated a.c power supply to these expensive appliance/equipment must sought for.
The cost of purchasing some already made imported voltage stabilizer is enormous. Not readily available in our local markets while importing them requires high foreign exchange, the sown tunes is also much before, there is need to embark on this project work the design and construction automatic voltage stabilizer any form of voltage fluctuating (under voltage or over voltage) from the NEPA mains supply to domestic and industrial consumer premise. It is also one of the objectives of this project work that cost comparison between the imported or factory assembled voltage stabilizer e.g SORTEX OR BINATONE products and a locally fabricated voltage stabilizer be embarked on and that work be done on this project in order to finally produce a device that would perform optimally and also relatively cheaper.
1.2 TRANSFORMER CONFIGURATION
These AVRs are fitted with isolating transformers, one per phase. These provide a high degree of isolation from input to output. They also greatly attenuate common mode noise from the supply and prevent it reaching the load.
The primaries are each nominally 415V rated and are connected in a delta configuration. Indoor 50A and outdoor 50A AVRs, the primaries are made up of two coils connected in parallel. The 12A and 20A transformers have single coils.
The secondary voltages are nominally 230V rated and are connected in a star configuration so as to generate a new neutral point. The secondary are in fact made of two coils each connected in parallel.
A further advantage of the delta input configuration is that an incoming neutral connection is not required from the supply. Often neutral supply connection are poor or missing and this can cause damage to loads and regulators due to high phase to neutral voltages that result.
1.3 SIGNIFICANCE OF THE PROJECT
The Automatic voltage regulator is a voltage regulator planned to mechanically sustain a constant voltage level. It is very device to maintain a constant voltage level. It can also use electromechanical components. It can be used majorly to regulate one or more DC or AC depending on the design. Therefore, the functions of this equipment are very wide and can be used majorly for various purposes. Electronic voltage regulators can be used majorly for various purposes. It has various functions like it can be used mainly for stabilizing the DC voltages that can be used by the processor and its main parts. In central power station generator plants and automobile alternators, voltage regulators control the output of the plant. In this distribution system, it may be installed at along distribution lines so that all clients recognize steady voltage self-regulating of how much power is drawn from the line. There are many functions of operating the AC depending upon the design. It is very good option to maintain the constant voltage level. Automatic voltage regulator is a superb invention of science, which is an electric device designed to authorize a constant voltage in a settable level. It is very helpful to maintain the preferred voltage for the generators within particular limits. The main working of it depends upon the laws of electromechanical physics. It consists of numerous vigorous and unreceptive electrical parts like thermostats, adopters and diodes. Apart from this, there are many reliable Automotive Suppliers in India that produce many kinds of equipments like generator, regulator and other major parts. They are well known for various kinds of functions and various specifications. They not only produce higher quality products, but also they will provide some additional benefits with the parts of these equipments. Auto Voltage Regulator Generator is the most important part for great amplifier to work. Its types are many, but they are highly in functionality and better performance. They are well equipped with self functioning controls and starts up functions which make them very easy and useful to handle easily and completely. They have different sizes, shapes and colors. There are also automatic regulators which are so small that they can be easily places on a small printed circuit board. They are very easy and portable to handle. They may cover a higher volume of small house sometimes. Therefore, there is a wide variety in the automatic voltage regulator sand each has its own specifications.
1.4 THE SCOPE OF THE PROJECT
The design and construction of an Automatic Voltage Regulator is the project we are construction. We are working on this machine because we have some idea on how this machine can be constructed and also on how it works. We are also doing this because we want to learn more about it.
As we have mentioned earlier, this device is a protective device that protects our electrical and electronic appliances out of current and voltage fluctuation. This is how it works. When this system is plugged into the socket or supply, it will receive a minimum voltage of 100v and filter the current and voltage thereby brings out suitable voltage output to be used by the devices in it.
So, we are building or constructing this device to reduce risk and damages the fluctuation of current / voltage caused by power fluctuations.
1.5 LIMITATION OF THE PROJECT
The system design shall be capable of operating at an input frequency range of -15% to +10% of nominal, without clearing protective devices or causing component failure within the AVR. When generator or utility power is restored, the AVR shall automatically restart. Upon turn on or restart, the output of the AVR shall not exceed the specified output regulation limits.
If the input voltage or frequency exceeds programmable minimum or maximum set points for a programmable time period (factory set for 10 seconds), the AVR shall electronically shut off. When electrical parameters are back within acceptable limits for a programmable time period (factory set for 60 seconds), the AVR shall automatically restart to provide conditioned power to the load. If the input parameters are within acceptable limits, but the output voltage is outside of acceptable programmed limits, the AVR shall electronically shut off and require a manual restart.
The AVR shall be capable of operating at 100% rated load capacity continuously, 200% rated load for 10 seconds, 500% rated load for 1 second and 1000% rated load for 1 cycle. Operating efficiency shall be a minimum of 96%, typical at full load.
Transformer winding shall be continuous copper with electrostatic tripled shielding and K-13 rated for the purpose of handling harmonic currents.
Response Time: The AVR shall respond to any line voltage variation in 1/2 cycle while operating linear or non-linear loads, with a load power factor of 0.60 of unity. Peak detection of the voltage sine wave shall not be permitted to avoid inaccurate tap switching due to input voltage distortion.
Operating Frequency: The AVR shall be capable of operating at +10% to -15% of the nominal frequency, 50Hz or 60Hz.
Rating: this device shall be rated at kVA.
Access Requirements: The AVR shall have removable panels on the front, rear and sides as required for ease of maintenance and/or repair.
Metering: An input meter is provided to display line voltages
Ventilation: The AVR isolation transformer shall be designed for convection cooling. If fan cooling is required for the solid state electronic switching devices.
1.6 PROJECT WORK ORGANISATION
The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:
Chapter one of this work is on the introduction to the study. In this chapter, the background, significance, objective limitation and problem of the study were discussed.
Chapter two is on literature review of this study. In this chapter, all the literature pertaining to this work was reviewed.
Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.
Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.
Chapter five is on conclusion, recommendation and references.
DESIGN AND CONSTRUCTION A THREE PHASE AUTOMATIC VOLTAGE STABILIZER
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