This project report describes on the design, development and fabrication of one demonstration unit of the project work “Transformer Failure Preventer with Data Transmission Using Microcontroller”.
In this contribution a new device for protecting and monitoring of dry type transformers will be presented. In addition to monitoring and control of power transformer, the failure information, i.e., due to what reason the transformer has been failed can be transmitted to the centralized monitoring station, from where the condition of the transformer is monitored remotely.
The over all system is designed with Microcontrollers, one used in the transmitting module and the other in the receiver performs as decoder.
Output of this Microcontroller is displayed on the LCD. In the system lot of care is taken to protect the power transformer, burning due to the overload and over temperature. Using semiconductor sensor performs an online overheating protection.
* The developed monitoring system is efficient and cost-effective and can be easily installed on almost all categories of dry type transformers.
Nowadays, we find lot of transformers are burning because of
- over loads,
- voltage variations and
- Over heating.
The body temperature of a transformer rises due to overloads and continuous long run, because of these reasons the transformer may shutdown .In the rural areas transformers shutdown due to agricultural pump-sets, and we know it takes lot of time to repair and it involves lot of cost.
Hence, the transformer failure prevention has become essential for smooth transmission and distribution. For simulation of the faults in the demonstration unit a step-down transformer of 1amp current rating is used and above parameters are carried over this transformer and the corrective action is initiated when the parameters crosses its limits.
For monitoring the transformer body temperature, semi-conducting device is used as a temperature sensor and this transducer is wired with operational amplifier. Similarly for monitoring the load current, the current transformer (CT) is used which gives the secondary voltage proportional to the current flowing in the primary. The primary of the CT is connected in series with the load.
Thus, this project work simulates the substation environment and any transformer crosses any of these parameters, then the input to the transformer is disconnected and prevents from burning the transformer. Hence this project work is titled as Transformer Failure preventer with Data Transmitter.
Now coming to the transformers, a transformer is a static piece of apparatus by means of which AC power in one circuit is transferred to AC power of the same frequency in another circuit. This transformation of Electric power usually takes place with a change in voltage level. When the transformer raises the voltage i.e., output voltage is higher than the input voltage, it is called a step-up transformer, on the other hand, when it lowers the voltage, it is called a step-down transformer.
Distribution transformer failures have been an expensive problem for the Electricity boards, mainly in rural networks. Transformer failures have many causes and variables involved, like natural phenomena (lightning, wind, forest), no natural phenomena (human errors), design, build (manufacturing problems, materials defects) and transformers and networks (lines, protection equipment, structures) maintenance.
- Research centers and consultants have done particular diagnosis studies and punctual solutions in order to reduce transformer failures and improve network performance.
- The developed monitoring system is efficient and cost-effective and can be easily installed on almost all categories of dry type transformers.
Block diagram and its description:
The block diagram and its brief description of the project work “Transformer Failure Preventer With Data Transmission using Microcontroller” is explained in block wise. The total block diagram of this project work is provided at the end of this chapter and this block diagram consists the following blocks.
- Load Monitoring Circuit
- High Voltage Monitoring Circuit
- Temperature Sensing Circuit
- Low Frequency Oscillators
- F.M. Transmitter
- F.M. Receiver
- Signal Amplifier
- Frequency to Voltage Converter
- Analog to Digital Converter
- Clock Generator
- .LCD Panel
TRANSFORMER FAILURE PREVENTER WITH DATA TRASMISSON USING MICROCONTROLLERS
Load Monitoring And Control Circuit
The voltage induced in CT is proportional to the load current. The variable voltage from the CT secondary is fed to analog to digital converter for converting the analog information into digital information.The output of the A/D converter is fed to Micro-controller unit. When the load current exceeds the prescribed value, Micro-controller unit energizes the common relay and current relay.
High Voltage Monitoring Circuit:
the output of the line voltage sensing circuit is fed to micro-controller unit through the A/D converter, so that according to the received digital information form the ADC, the micro- controller energizes relay. This relay contact is used to break the supply to the feeder cable.
Temperature Sensing Circuit:
The temperature sensing circuit, which monitors the distribution transformer body temperature, at the transmitting end is designed in such a way so that, if the temperature exceeds a preset value, automatically, relay-2 will be energized and 2KHz tone signal will be produced, which is super imposed over the carrier frequency of 100MHz and it is transmitted along with the carrier.
Low Frequency Oscillators:
In this project work, three different Tone generators are constructed using three 555 timer IC's and generated three different tone frequencies for identifying the failure parameter at the receiving end. These timers are configured in astable mode of operation (free running oscillators).
This circuit design, the instantaneous frequency of the carrier is varied directly in accordance with the base band signal by means of a device known as VCO (Voltage controlled oscillator) one way of implementing such a device is to use a sinusoidal oscillatory having a relatively high - Q frequency. Determining net work and to control the oscillator by symmetrical incremental variation of the reactive components. Thus the tone signal modulated at 100 MHz carrier. Radio wave are generated and radiated into space through the antenna.
The FM receiver is located at the remote end. The first stage of this remote end unit is the F.M. Radio Receiver, which is designed with Phillips IC TEA 5591A. Which operates at 100 MHz, This IC consists of a built in RF amplification circuit. It matches the input impedance of the antenna. This IC consists of F.M. Detector including amplifier of modulated signal (RF amplification).
For maximum power output and impedance matching the audio frequency driver transformer is used in the signal amplifier circuit. The signal, which is detected by the receiver, is further amplified with the help of audio amplifier. The output of this signal amplifier is fed to the F/V converter.
Frequency to Voltage Converter:
The output of the signal amplifier is converted into DC voltage in proportion to the tone frequency, with the help of phase locked loop IC 4046 and Multi-plexer IC4053. The output of the F/V converter is fed to the Analog to digital converter circuit for converting the Analog information into digital pulses.
Analog to Digital Converter:
The output (Frequency proportional DC voltage) of frequency to voltage converter is fed to the ADC 0809. Analog to digital converter and the clock rate at which the conversion is fed from the IC 555 timer configured as astable multi-vibrator. The digital output after conversion is fed to controller
Software Requirements and Relays:
Keil development tools for the 8051 Microcontroller Architecture support every level of software developer from the professional applications engineer to the student just learning about embedded software development. The industry-standard Keil C Compilers, Macro Assemblers, Debuggers, Real-time Kernels, Single-board Computers, and Emulators support all 8051 derivatives and help you get your projects completed on schedule.
A relay is an electrical switch that opens and closes under control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad sense, to be a form of electrical amplifier. These contacts can be either normally-open, normally-closed, or change-over. Acts connect the circuit when the relay is activated; the circuit is disconnected when the relay is inactive. Normally-closed contacts disconnect the circuit when the relay is activated; the circuit is connected when the relay is inactive. Change-over contacts control two circuits: one normally-open contact and one normally-closed contact.
TYPES OF RELAYS:
- Latching Relay
- Reed Relay
- Mercury Wetted Relay
- Machine Tool Relay
- Solid State Relay (SSR)
The micro-controller is a chip, which has a computer processor with all its support functions, memory (both program storage and RAM), and I/O built in to the device. These built in functions minimize the need for external circuits and devices to be designed in the final application. The 89C51 manufacturer's products taken into account, there are over two hundred different 89C51 part numbers, each with different features and capabilities. For most applications, we will be able to find a device within the family that meets our specifications with a minimum of external devices, or an external but which will make attaching external devices easier, both in terms of wiring and programming.
Work Plan and Tasks
The tasks and their respective duration have been planned to execute within the period of four months from 13th March 2009 to 14th July 2009.
- Ordering software like Keil
- Referencing books and journels for designing controller module
- Get internship with the corresponding power station
- Planning the design in simulation software Keil
- Practical design of the controller module
- Practical implementation of the controller kit and waiting for the approval
Funding and Budget
For the start and complete of this successful project, we shall request funding from HBL Power systems Pvt Ltd, India, this organization is been principal support for executing this project and make it successful.
The budget required for this completing the project is as shown below
Micro Controllers and other electronic chips
FM, transmitter and receiver
Manuals and books
Flight Fare to India
Project Impact, project Limitations and ethical considerations.
The project work “Microcontroller Based Transformer Failure Preventer with Data Transmission using Microcontroller” is successfully designed, tested and a demo unit is fabricated.
the limitation is being made in this project work is to monitor the three important parameters, such as load current, temperature and input high voltage. Apart from these three parameters, various other parameters, such as line frequency, power factor, power leakage, Energy measurement etc; can be incorporated in this project work.
Apart from using Micro-controller, Microprocessor or Computer also can be used. The advantage of using PC is, the parameters not only monitored, but also periodically the data can be logged and the same data can be stored. So that details of the parameters can be monitored on the screen. There by this data can be used for taking suitable decisions. The control circuit used in this project work can be utilized for the real applications with minimum modifications.
(1) Linear Integrated Circuits - By: D. Roy Choudhury,
(2) Power Electronics - By: SEN
(3) Relays and their applications - By: M.C.SHARMA
(4) Op-Amps Hand Book - By: MALVIND
(5) Mechanical and Industrial Measurements - By: R.K. Jain
(6) Digital and Analog Communication System By: K. sam Shanmugam
(7) Programming and Customizing the 8051 Micro-controller
- By: Myke Predko
(8) The concepts and Features of Micro-controllers - By: Raj Kamal
(9). The 8051 Micro-controller Architecture, programming & Applications
By: Kenneth J. Ayala
(10). The IC 555 Timer Applications Source book By: HOWARD M. BERLIN
With the help of this book 1KHz & 2KHz tone generator circuits are designed.
(1) TEXAS - LINEAR IC's manual
(2) SIGNETICS - DIGITAL IC's manual
(1) Electronic Design
(2) Electronics for you
(3) Electronics Text.
(4) Practical Electronics