POWER LINE CARRIER COMMUNICATION FOR DISTRIBUTION AUTOMATION SYSTEM M.Sinduja,S.Ranjitha Department of Electrical & Electronics Engineering, Bharathiyar Institute of Engineering For Women, Deviyakurichi. ABSTRACT: In an industrial setup or a home environment very often there is a need to control electrical machines or devices from a remote location. At present many remote control techniques are available each suitable for some particular cases. But all the remote controls needs different medium to carry the control signals. Commonly, all the industrial machinery or appliances at home are connected to the power lines. Hence this paper makes use of the already existing power lines as a physical medium to control the machines and it allows the user to select the particular machine using its code and control it easily.. Key words: Power system communication, Power system modeling, attenuation, MP 8.3. INTRODUCTION Power line carrier communications (PLCC) refers to the concept of transmitting the information using electrical power distributing network as a communication channel. This technology allows a flow of information through the same cabling that supplies electrical power. This novel idea of communication helps in bridging the gap existing between the electrical and communication network. It offers the prospect of being able to construct industries, where all the devices can be monitored and their various parameters also controlled from a remote location. NEED FOR AUTOMATION Inadequately industrial network leads to, Poor performance. Tough maintenance. Decrease in life time. compensated Needs extra medium to control. Needs extra cable. Noise interference. Due to the above mentioned reasons there is a need for compensation. So we are going for automation. SCOPE OF THE PROJECT The main advantage of automation over distribution system through power line carrier communication technique is obtaining good performance. That it does not require any extra medium to carry the control signal. Moreover, the communication is transparent to the users. It displays the performance of the motor in the LCD Display. And their installation process is very simple. They are in general, cheaper and require less maintenance. ISSN: 2348-8379 www.internationaljournalssrg.org Page 32
BENEFITS PLCC integrates the transmission of communication signal and 50Hz power signal through the same electric power cable. The major benefit is that the union of two important applications on a signal system. The data link appears transparent to the user. Although the devices are connected through the power line, consumers perceive that there is a separated link available for data communications. Since the existing power lines are used for signal transmission, the initial heavy cost and investment for setting up a data communication system is avoided. HARDWARE IMPLEMENTATION Fig: RECEIVER SIDE The project comprises of monitoring and controlling the various parameters of the stepper motor using PLCC (Power Line Carrier Communication) Modem with the help of PIC Microcontroller. The input will be given to the PIC Microcontroller through the switch or keypad. Microcontroller will be programmed in such a manner using Embedded C to avoid complexity and traffic complication. Microcontroller and PLCC Modem are used in pairs at both the sides. Fig: TRANSMITTER SIDE Microcontroller produces the digital output and is fed to the PLCC Modem. PLCC Modem consists of a 555 timers, power line modulator, filter circuit, isolation circuit, etc. 555 Timer converts a single pulse into multipulse and power line modulator changes low signal into high signal that matches the power line frequency. Noise filter is used to avoid noise interference in the power line while transmitting and receiving. Isolation circuit act as a control ISSN: 2348-8379 www.internationaljournalssrg.org Page 33
circuitry which is mainly used avoid entrance of unwanted signal on either side of the system. During transmission, the digital signal from the microcontroller will pass through the 555 timer, power line modulator and isolation circuit. Then, the signal will be send through the power line with the help of isolation circuit. Isolation circuit consists of inductors and capacitors, which is used to attach the data in the power line. The transmitted signal from the power line will be received by PLCC Modem on the receiver side. Here, the signal will pass through filters to eliminate the noise from the power line and reaches the microcontroller. Microcontroller in the receiver side will produce control signal that is used to drive the driver circuit of the stepper motor. The speed of the motor can be continuously monitored by using speed sensor connected to the microcontroller. Thus the varying control signal from the microcontroller performs different control action to control the various parameters of the stepper motor. Power Line Carrier Communication System is a user transparent system, so that the performance of the motor can be monitored in the LCD display connected to the microcontroller on the transmitter side. Here the signal about the motor performance will be passed through the power line modulator and isolation circuit at the receiver side. Then the signal is passed through the power line and reaches the transmitter side where the signal is again passed through the noise filter to eliminate the noise interference from the power line. Finally, the signal will be given to the microcontroller which displays the motor action at the transmitter side. Unlike conventional systems that use multiple frequencies, it uses single frequency. Thus, this technique is highly reliable and does not require any extra medium for communication. a) PLCC MODEM The new ATL90 series Embedded PLCC modem series is based on the Direct Sequence Spread Spectrum Technology. The new technology in Power Line Carrier (PLC) communication is well known for its high immunity to electrical noise persistent in the power line. With the new solution, the form factor of the PLCC modem is further reduced and its cost lowered. The Embedded PLCC Modem is in the form of a ready-to-go circuit module, which is capable of transferring data over the power cable at the low voltage end of the power transformer. A pair of Embedded PLCC Modems connected on the power line can provide low speed bidirectional data communication at a baud rate of 300/600 bps. It is built in a small form factor that can be easily integrated into and become part of the user's power line data communication system. The modules provide bi-directional halfduplex data communication over the mains of any voltage up to 250V a. c., and for frequency of 50 or 60 Hz. Data communication of the modules is transparent to user's data terminals and protocol independent; as a result, multiple units can be connected to the mains without affecting the operation of the others. The use of DSSS modulation technique ensures high noise immunity and reliable data communication. There is no hassle of building interface circuits. Interface to user's data devices is a simple datain and data-out serial link. It has a built-in on board AC coupling circuit, which allows direct and simple connection to the mains. ISSN: 2348-8379 www.internationaljournalssrg.org Page 34
Self-reprogrammable under software control. Single supply 5V In-Circuit Serial Programming. Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable operation. Programmable code protection. Power saving SLEEP mode. LCD DISPLAY a) PIC MICROCONTROLLER AND LCD DISPLAY The term PIC, is the name given by Microchip Technologies to its single-chip microcontrollers. PIC micros have grown to become the most widely used microcontrollers in the 8- bit microcontroller segment. The PIC16F877 is 40 pin IC. There are five ports in this microcontroller. Namely PORT A, PORT B, PORT C, PORT D and PORT E. Among these ports PORT B, PORT C and PORT D contains 8-pins, where PORTA contains 6-pins and PORT E contains 3-pins. Each pin in the ports can be used as either input or output pins. Before using the port pins as input or output, directions should be given in TRIS register. For example setting all the bits in TRIS D register indicates all the pins in PORT D are used input pins. Special Microcontroller Features 100,000 erase/write cycle Enhanced FLASH program Memory typical. Data EEPROM Retention > 40 years. In this project we use LCD display to display the speed of the stepper motor in RPM at running condition. It is connected to the controller and a program has been written to display the speed sensors reading. Liquid crystal cell displays (LCD s) are used in similar applications where LEDs are used. These applications are display of numeric and alphanumeric characters in dot matrix and segmental displays. b) ISOLATION CIRCUIT Power line isolating circuitry consists of an inductive coil and the capacitor. This inductive coil and the capacitor combination acts as a LC filter. Hence the filter is so designed that its cut off frequency is above 1 KHz. So any frequency below 1 KHz is blocked. The power line frequency is about 50Hz or 60Hz. These frequencies are very low though its voltage is very high. Hence the LC filter blocks these frequencies from moving. Isolation transformers which occur in the power distribution system effectively limit the available bandwidth to a very low value. c) MP LAB MPLAB Integrated Development Environment (IDE) is a free, integrated toolset for the development of embedded applications employing Microchip's PIC and dspic microcontrollers. MPLAB IDE runs as a 32-bit application on MS Windows, is easy to use and includes a host of free software components for fast application development and super-charged ISSN: 2348-8379 www.internationaljournalssrg.org Page 35
debugging. MPLAB IDE also serves as a single, helpful, time saving and a method that we can unified graphical user interface for additional rely on the user. Microchip and third party software and hardware development tools. Moving between Future work is focused on continued benchmarking and improved accuracy of the tools is a snap, and upgrading from the free components in higher frequency ranges. Also, it software simulator to hardware debug and is recommended that simulated results be programming tools is done in a flash because compared against actual field measurements. It MPLAB IDE has the same user interface for all could be useful to develop various components tools. that facilitate frequency scans, interpret results, and make recommendations on selection of Features Of Mplab carrier frequency. MPLAB IDE contains additional features to aid in device setup, code debugging and general support. Configuration Bits Watch Window Breakpoints High-Level Language Support. APPLICATIONS Air Conditioning Control Lighting Control Status Monitoring and Control Low Speed Data Communication networks Intelligent Buildings Signs and Information Displays Fire and Security Alarm System Power Distribution Management Home automation. REFERENCE H.W. Dommel with S. Bhattacharya, V. Brandwajn, H.K. Lauw and L.Martí, Electromagnetic Transients Program Reference Manual (EMTP Theory Book), Bonneville Power Administration, Portland, USA, 1992 2nd Edition. IEEE Guide for Power-Line Carrier Applications. An American National Standard. ANSI/IEEE Std 643-1980. IEEE, 1980. B.A. Mork, D. Ishchenko, X. Wang, R.P. Quest, and C.P. Kinney Simulation of Power Line Carrier Communications Systems, presented at the EEUG Meeting, Trondheim, Norway, and October 3-5, 2004. www.scribd.com www.onlinedatasheets.com www.todayscircuits.com CONCLUSION AND EXTENSION Our project has been successfully completed and is tested at our campus. We conclude our project with the perspective that we have contributed our part in the automation on distribution system through power line. Also we hope to have given an efficient system which not only monitors the motor performance. But also helps to control the various parameters of the different motors at a remote place. This method of maintenance system moves to be very ISSN: 2348-8379 www.internationaljournalssrg.org Page 36