30-06-2012, 01:53 PM
A REPORT ON PRACTICAL TRAINING TAKEN AT PLCC SECTION 220KV G.S.S., HEERAPURA POWER HOUSE “JAIPUR”
PLCC STAFF OF 220KV G.S.S HEERAPURA for their co-ordination & support in problem .....docx (Size: 59.23 KB / Downloads: 198)
PREFACE
The objective or main motive of this practical training is to getting a true practical knowledge about the industries, that how their industrial setups are held, and their communication techniques used in industry technologies to be made or used in the environment.
This report is presented on the basis of practical training acquired at PLCC SECTION of 220KV, HEERAPURA G.S.S.(GRID SUBSTATION). This report is on PLCC with relevant diagrams & by their proper description & explanation.
In spite of all my best efforts some unintentional errors might have eluded, it is requested toabrogated them.
ACKNOLEDGEMENT
I am very grateful to Mr. Ravindra Kr. Garg (Assistant Engineer) for his very useful guidance, technical & much advantageous lectures .
I would also like to express my sincere thanks towards PLCC STAFF OF 220KV G.S.S HEERAPURA for their co-ordination & support in problem solving .
INTRODUCTION OF R.S.E.B.
Rajasthan state electricity board started working from 1stjuly 1957. This is a body of big organization and is to function under provision electricity act,like public limited companies. The board does not have article and memorandum of association.
In order to carry out its function,it has rules and regulations ans has made other neccesaries administrative arrangement.After the action of RSEB six dimention along with 64 offices and about 300 employies were transferred to its control by the state government.
The aim of RSEB is to supply electricity to entire rajasthan state in the most economical way. There is no possibility of staking or electricity so the target of board is to distribute the energy in new area as possible. The board has to carry the bussiness on profit without losses.
INTRODUCTION
Power Line Carrier Communications (PLCC) is the use of existing electrical cables to transport data, and it has been around for a very long time. Power utilities have been using this technology for many years to send or receive data on the power grid using the existing infrastructure. For instance, the electrical power utility in London used PLCC to remotely control some of its equipment on the grid (such as high- voltage switches) in the 1920s. This technique is still employed by several utilities that use analog or digital devices to transfer 9.6 Kbits/s over many miles of electrical cable. In the 1920’s at least two patents were issued to the American Telephone an Telegraph Company in the field of “Carrier Transmission over Power Circuits”. United States Patents numbers 1,607,668 and 1,672,940 filed in 1924 show systems for transmitting and receiving communication signals over three phase AC power wiring. Other have suggested that what was required for power line communication to move into the main stream was a commercialized version of military spread spectrum technology. It has been suggested that this is what was needed in order to overcome the harsh and unpredictable characteristics of the power line communication has been the focus of research and product development at a number of companies since the early 1980’s.
Before proceeding further we have to take the knowledge about the basic concepts of transmitting the data from one place to another known as modulation.
MODULATION:-
Modulation is a process/technique, in which we can superimposed the carrier wave on the modulating wave (signal ), in the process one of the parameter of the carrier wave only be varies while keeping remaining two as constant with respect to the modulating signal. This process is known as Modulation.
Types of modulation:-
Amplitude modulation
Frequency modulation
Phase modulation
Amplitude Modulation:- In the amplitude modulation the amplitude of the carrier wave only varies, according to the modulating signal while keeping the remaining parameter’s are as constant, know as amplitude modulation.
Frequency Modulation:- In the Frequency modulation the Frequency of the carrier wave only varies, according to the modulating signal while keeping the remaining parameter’s are as constant, know as frequency modulation.
Phase Modulation:- In the phase modulation the phase of the carrier wave only varies, according to the modulating signal while keeping the remaining parameter’s are as constant, know as phase modulation.
After modulating the signal by using one of these techniques the signal is now transmitting to another station, & before distributed at another station the signal is demodulated.
Demodulation:- As than name says it’s the inverse process than modulation in which we can separate out the carrier signal to modulating signal.
PLCC technology is used for the following these places which are given below:-
1. Point to Point Communication (Hot line Communication)
2. Data telemetry purpose
3. Tele protection purpose
Point to Point Communication:- Point to Point Communication states that the communication in between two particular stations. Now the question is arises that why we go towards that communication when mobile and telephone are available. Two problems are arises in mobile communication.
First is when we are using mobile that the networking problems may arises.
Second thing is someone at any stations may busy talking with another person while/when you are try to call him.
Date Telemetry:- PLCC terminals can be used for sending and receiving data signal for telemetry etc . The input signals for this channel will be in between 2000-3000Hz.
Tele Protection:-Protection coupler Equipments can be used along with PLCC terminals for telemetry purpose.
During line fault other fault occurring between sub station trip signals can be transmitted or received by a protection coupler through PLCC terminal for activation distance protection Relaying Equipment.
In PLCC the higher mechanical strength and insulation level of high voltage power line communication and lower attenuation over long distance. The idea is to use the power line as a transmission line for communication purpose.
Basic principles of PLCC:- Telephone communication system can not be directly connected to the high voltage power line; therefore we have to suitably design the coupling devices. These usually consist of high voltage capacitor or capacitor with polaritical devices & used in the conjunction with the suitable line matching unit for matching the line impedance to that of the co axial cable connecting the PLCC Equipment.