INTRODUCTION TO GGSSTPR

Electrical energy occupies top position in the energy table. It can be adopted conveniently in the domestic, industrial and agriculture fields. The availability of electrical energy and its per capita consumption is regarded as an index of national standard of living in the present day civilization. The lack of electricity can hinder the economic as well as social progress of the country.

Next to food, fuel and power are the most important items on which the standard of life depends. Every effort is or has been made to utilize the various natural as well as artificial sources of energy in order to increase the power potential of the nation. The energy in the form of electricity is the most desired since it is the most economical, easy transmission, easy control, cleanliness, greater flexibility, versatile form and can be converted into heat and work as and when desired. The main sources of energy generation in India are solar, wind, tidal, hydro, thermal and nuclear.

Every effort is being made to utilize full potential of energy development available. However, if we look at the data available and compare it with the developed countries, we can say that we are still a far to go. The figures below indicate the present sources of energy and their respective division.

TOTAL INSTALLED CAPACITY : 89,798 MW

PEAK DEMAND : 67,500 MW

COAL BASED THERMAL PROJECTS : 65,000 MW

HYDRO PROJECTS : 22,000 MW

NUCLEAR PROJECTS : 2000 MW

WIND POWER : 900 MW

THERMAL POWER GENERATION

In steam power plants, the heat of combustion of fossil fuels (coal, oil or gas) is utilized by the boilers to raise steam at high temperature and pressure. The steam so produced is used in driving the steam turbines or some times steam engines coupled to the generators and thus in generating energy. Oil and natural gas reserves are small in our country, India has to import large quantities of oil, and increasing such imports for power generation is not desirable due to miserable amount of foreign exchange reserves India has. This explains the dependence on coal for generation of electricity in thermal power plants.

Large development in thermal power generation calls for proper choice of site, unit size, coal requirements, transport facility, transmission systems etc. It is normal practice to consider various alternative sites for locating power stations and work out cost comparison to arrive at economically feasible sites.

WORKING OF THE THERMAL PLANT

Thermal power station burn fuels and uses the resultant steam to drive the turbo generator. The object is to convert heat into mechanical energy in the turbine and to convert mechanical energy into electrical energy by rotating magnets inside a set of magnets. The coal brought to the station by means of trains travel from the coal handling plant by conveyor belts to the coalbunkers. From where it is fed to, pulverizing mills which grind it to a fine powder. Finely powdered coal mixed with preheated air is blown into the boiler by primary air fan where it burns more like a gas than as a solid with additional amount of air called the secondary air supplied by the secondary draft fan. As the coal has been ground finely, the resultant ash is fine powder. Some of its contents bind together to form lumps, which fall in ash pits at the bottom of the furnace. The ash mixed with water is then taken to the pits for subsequent disposal. The electrodes charged by high voltage electricity in the electrostatic precipitator trap most of the ash. The dust is then conveyed by water to the disposal area or to the bunkers while the cleaned flue gases pass on through the ID fan to discharge through the chimney. Meanwhile the heat released from the burning of coal has been absorbed by many kms of tubing which line the boiler. Inside these tubes is water, which takes the heat and is converted into steam at high temperature and pressure. This steam at high temperature and pressure is sent to the turbine where it is discharged through the nozzles on to the turbine blades. The energy of the steam striking on the blades makes the turbine to rotate. Coupled to the turbine is the rotor of the generator. Therefore, when the turbine rotates the rotor of the generator turns. The rotor is housed inside a stator having heavy coils of copper bars in which electricity is produced through the movement of magnetic field produced by the rotor. Electricity passes from stator winding to the transformer, which increases its voltage level so that it can be transmitted over the lines to far off places. The steam, which has given away its energy, is changed back into water in the condenser. Condenser contains many kms of tubing through which cold water is continuously pumped. The steam passing over the tubes continuously loses heat and is rapidly changed back into water. However, the two waters i.e. the boiler feed water and cooling water must never mix.

Boiler water must be pure otherwise the tubing of the boiler may get damaged due to the formation of salts inside the tubes due to the presence of different impurities in water. To condense large quantities of steam huge and continuous volume of water is required. In some power stations, same water has to be used repeatedly because there is not enough water. Therefore, the hot water extracts are passed through the cooling towers. The cooling towers are simply concrete shells acting as a huge chimney creating a draught of air. The design of cooling towers is such that a draught of air is created in the upward direction. The water is sprayed at the top of the tower. As it falls down the air flowing in the upward direction cools it. The water is collected in a pond from where the water is re-circulated by the pumps to the condenser. Inevitably, the draught of water in the form of vapors takes some of the water away and it is this water with familiar white clouds emerging from the cooling towers.

BRIEF HISTORY OF THE PLANT

Guru Gobind Singh Super Thermal Plant is built at a site adjacent to Nangal Hydel Channel near Sirsa Aqueduct on a piece of land bounded by Sirsa, Mansali and Sutlej rivers. It is about 55 Kms from Chandigarh near village Ghanauli on Ropar-Nangal road. Ever widening gap between power demand and its availability was one of the basic reasons for envisaging the Guru Gobind Singh Super thermal plant for the Punjab State. The historic town of Ropar was selected for this project for easy transportation of coal by railway, availability of cooling water and land. The costly cooling towers have been avoided, as the cooling water temperature is very low. Smt. Indira Gandhi laid the foundation stone in December 1980. The total installed capacity of the power station is 1260 MW with 6 units of 210 MW each in three stages each of two units and the power plant comes in the category of Super Thermal Plants in India.

This plant was awarded Meritorious Productivity Awards and cash rewards by Govt. of India for its good performance during the years: 1985,1986,1987,1990 & 1992. Special care has been taken to keep the atmosphere pollution free by providing electrostatic precipitators with an efficiency of 99.7%, which extracts ash from the flue gases going out from the boiler. Chimney height has been increased to 220 metros for wide spread of gases at longer distance from the Power Plant to keep the ambient air clean

SALIENT FEATURES OF GGSSTPR

1. Cost of the Plant: 1417 Crores

2. Date of Start: 30 December 1980

3. Land: Main Plant Area : 210 Acres Marshalling Yard : 533 Acres Railway Siding : 65 Acres Ash Disposal : 974 Acres Residential Area : 492 Acres Total area : 2274 Acres

4. Railway Track: Length of Siding from Ropar : 8.315 Km Marshalling Yard : 38.330 Km

5. Chimney Height: Unit 1 & 2 : 140 Mt Unit 3 & 4 : 220 Mt Unit 5 & 6 : 220 Mt

6. Coal: Average Daily Requirement : 3000 Mt/Unit Total Storage of Coal : 4,00,000 Mt Ash Generated Daily : 1200 Mt/Unit

7. Heavy Fuel Daily Requirement: 3000 Mt/Unit

8. Water Requirement: For Stage 1, 2, 3 : 750 Cusecs Consumptive Requirement : 21.25 Cusecs/Unit 9. Total Ash Handling: 18, 00,000 Mt/Year (Variable)

INTRODUCTION TO AUTOMATION

It is continuous process industry, which works round the clock. All the equipment is covered under the automation and its parameters and health monitoring is being monitored by the Engineers in the main control room(UCB) beside local monitoring by the operator who sits beside the equipment .The main equipment is being operated and monitored through Control and Instrumentation (C&I).The basic block diagram as below:-

BOILER TURBOGENERATOR

UNIT CONTROL ROOMUCB

TRANSFORMER

AUTOMATION BENEFITS

The main benefits of plant automation are to increase overall plant availability and efficiency. The increase of these two factors is achieved through a series of features summarized as follows:

Optimization of house load consumption during plant start-up, shutdown and operation, via: Faster plant start-up through elimination of control errors creating delays. Faster sequence of control action compared to manual ones. Figure

shows the sequence of a rapid restart using automation for a typical coal-fired station. Even a well-trained operator crew would probably not able to bring the plant to full load in the same time without considerable risks.

Co-ordination of house load to the generated power output. Ensure and maintain plant operation, even in case of disturbance in the control system, via: Co-ordinates ON/OFF and modulating control switchover capability

from a sub process to a redundant one. Prevent sub-process and process tripping chain reaction following a

process component trip. Reduce plant/process shutdown time for repair and maintenance as well as repair cost, via: Protection of individual process components against over stress in stable

or unstable plant operation. Bringing processes in safe stage of operation, where process components

are protected against overstress.

PROCESS STRUCTURE

The complex overall process is divided into individual sub processes having distinctly defined functions. These groups are termed as FUNCTIONAL GROUPS. These FUNCTIONAL GROUPS RESULT in a hierarchical process structure which is governed in the horizontal direction by the number of drives (such as motorized valves, fans, dampers, pump etc.) in the vertical direction, there is a distinction made between three fundamental levels namely:-

1. Individual control level 2. Group control level 3. Process control level

The function group is that part of the process, which fulfils a particular defined task, e.g. induced draft control, feed water control, blooming, will control, etc. Thus at the time of planning it is necessary to identify each function in a clear manner by assigning it to a particular process activity. Each function group contains a combination of its associated individual equipment drives .The drive level are subordinate to this level .The function groups are combined to obtain the overall process control function at the unit level.The above three levels are defined with regard to the process and not from the control point of view as shown in figure.

Unit Level Degree Function of Group Level Automation Drive level

Extent of Process

CONTROL SYSTEM STRUCTURE

The primary requirement to be fulfilled by any control system architecture is that it is capable of being organized and implemented on true process-oriented lines. In other words, the control system structure should map onto the hierarchical process structure. BHEL’s PROCONTROL P is a microprocessor based intelligent remote multiplexing system-meets this requirement completely.

SYSTEM OVERVEIW

BHEL’s control and automation system is a microprocessor based intelligent multiplexing system. This system is designed on modular basis, allows tightening the scope of control hardware to the particular control strategy and operating requirement of the process. Figure shows PROCONTROL P as a network control system for controlling and automating a complete power station. Regardless the type and extent of process to control, PROCONTROL P provides system uniformity and integrity for:-

Signal conditioning and transmission Modulating control ON/OFF, logic/sequential controls Individual and process protection Overall man-process interface

MAIN DESIGN CONCEPT

The PROCONTROL P system has been developed for full utilization of the serial data bus technique. The main characteristics of this technique are- Very high data transmission speed for real time control. Purely cyclic mode of operation (hence deterministic behavior and no

over load under any circumstances). Redundant, fault tolerant, multi-channel structure. Due to these characteristics, it has become possible to extend the bus technique into the process area (machine hall, boiler, coal mills etc.) and to obtain a truly distributed control system configuration having:-

Functional distribution of control functions Geographical distribution of control hardware The other main concept of PROCONTROL P is summarized as follows:-

Modular hardware and software Extended portioning Simple system configuration and programming Extended monitoring functions Hot repair capability PROCONTROL P requires no longer that the serial data exchange be confined to the electronics room, process computer and control room. The most obvious advantage of the PROCONTROL P truly distributed concept is cable saving, since most of the conventional signal cabling can be dispensed with. In addition to the signal cable cost saving, PROCONTROL P bus technique offers further benefits:-

Easy protection of signal transmission against fire, sabotage etc within the whole plant.

Very much shorter repair time in the event of major plant damage (e.g. fire, explosion).

Flexibility with respect to changes during erection and commissioning (addition of signals and actuator) and for later extensions.

Possibility of extending or linking the main control system to auxiliary

outside plant modules.

PROCONTROL P

PROCONTROL P is a registered trademark of BBC, Brown Broveri &Co. Ltd. Initially BHEL procured microprocessor based modules from BBC, Switzerland and then perfected their own processors modules namely processor PR 03. Processors modules provide plant automation with a microprocessor based intelligent remote multiplexing system utilizing a broadcast principle for fast date transmission and fault tolerance concept. By faster sequence of control action as compared to manual one. PROCONTROL P provides a uniform integrated and flexible solution for all the tasks encountered in the Distributed Digital Control and Automation of power stations and process industries.

DATA TRANSMISSION

The data transmission of PROCONTROL P is performed with simple two level bus systems (as shown in figure)-

Local bus Interplant bus The local bus interconnects all inputs, output and processing electronics modules, which are part of station. Each individual local bus is self contained, working independently from any other local or inter-plant bus. This technique enables to implement one electronics rack as a basic control hardware configuration. The inter-plant bus interconnects its related local buses via coaxial cables as shown in figure 4. This interconnection provides galvanic separation and dynamic data transfer. The local buses can be grouped together at the same location and geographically distributed over a large distance. The fault tolerant concept is also provided with data transmission. Data transmission for large plant control system is portioned over various intra-plant buses. These intra plant buses are grouped by pairs and are dedicated to certain plant areas as shown in figure 3. The local and intra-plant buses use serial communication with time division multiplexing. The message format is based on broadcasting state information in source-addressed messages. The features of this transmission are as follows:-

No side effects of function executions because each message is addressed exclusively by its source addressed and can be created only by corresponding source.

Convenient monitoring or funning systems because each message identifies its source.

Facilitation of incremental system construction and the extension of running system because added functions cannot effect the already running system part.

Natural supports of backward errors tracing because all messages carry their own identification.

Each message is cyclically transmitted over the local as well asIntra-plant buses regardless, weather the message has changed compare tothe previous transmission. The transmission frequency of each message is selectable and can be typically as low as every 10ms. The combine techniques of message broadcasting and cyclic transmission ensure-

Fast data transmission needed for real time control, regardless, where the input, output or processing modules are individually distributed along intra-plant buses. A full transmission cycle requires about 10ms only.

Active system monitoring, whereby each input, output, processing and transmission peripheral module is cyclically stimulated to respond. Failure to respond is automatically noticed and correspondingly annunciated.

Transmission path cannot be overload under any circumstances.

I = INPUT MODULE O = OUTPUT MODULE P = PROCESSING MODULE

PROCONTROL P BUSES

I O I O

LOCAL BUS

INTRAPLANT

BUS

LOCAL BUS

LOCAL BUS

I

I

O P

BENEFIT OF PROCONTROL P PARTIONING

PROCONTROL P extensive portioning concept. e.g. implementation of individual control modules dedicated to each final control element and portioned automation system presents various benefits, particularly, when process availability is of prime importance e.g. for the main plant power station. The benefits are summarized as follows:-

Degree and extent of automation can be exactly adapted to the process and operating requirement.

Process/plant can be operated at an early stage of the start up period via manual control over individual control modules, even if the automation system is not operational.

Automation islands can start up one after the other from the lower level up to the highest level.

The final control element’s permissive as well as protection function are active at individual control level. Even in manual mode operation, these signals remain active preventing final control element mis-operation.

INPUT/OUTPUT MODULES PROCONTROL P has various modules for input/output capability, which can be connected to any local bus. These modules can handle any type of signal, such as single, double throw contacts, thermocouple, RTD’s, milliamp signals, etc or to provide milliamp voltages, electronics or contract output signals. The input modules provide for a wide range of functions such as 1ms sequence of events, supply of individual power to contact, transmitters. These modules also have an extended an integrated monitoring capability to detect disturbance which may occur at the module, transmitter level (e.g. out of range) or in the field cabling. This monitoring feature has the following advantages:-

The input unit is totally self-contained and does not need the assistance of an additional microprocessor for monitoring, linearization etc. because of this feature supervision and monitoring functions do not have to be considered during system engineering or extension.

The supervision function of the input module comprises the completely measuring loop and the corresponding signal can be used in the monitoring functions of the entire control loop.

Distributed control/measurement loops can be easily and quickly isolated before wrong data are transmitted and/or processed.

The maintenance staff can be informed on any disturbance and routed to the source of disturbances.

In case of a disturbance in a measurement loop, the corresponding output module can retain the output status as it was prior to the disturbance or change its status according to a pre-determined position.

MAN PROCESS INTERFACE

PROCONTROL P over all man process interfaces is the actual interface between the plant management, operating/maintenance personal and the process as well as the control system. The function of this interface includes-

Operating station Plant monitoring system Engineering station The function of the man process interface does not include any control algorithms of the processes since these functions are the part of control and automation package. The man process interface works totally independent from the control and automation functions to keep a clear overall control system portioning. The data control and automation system is executed over the intra-plant buses. The modular concept of the man machine interface offers systems flexibility about dedicated conceptual portioning as shown in figure 9.

1. Operator station: The operator station can consists of two techniques: conventional station with push buttons, lamps and indicators or CRT based stations. Both these techniques can be implemented separately-where by redundant CRT station can be implemented-or both together. System portioning is also provided for the operator station.

The portioning of the conventional station is the duplicate of the portioning the individual drive control and automation function.

The portioning of the CRT based stations is selectable, e.g. according to plant area.

The conventional stations as well the CRT based station provide the operator with the possibility to give orders to individual control loop ( dedicated to each final control element ) and automation loops (switch on/off – manual/auto, change set – and actual value) as well as to supervise each loop in regard to control or disturbance status.

The CRT based station provides the possibility to tune individual control loop and perform interface-monitoring functions. Such simple indications functions, as tabulation, bar charts, trends, mimic displays or simple protocols.

2. Plant monitoring systems: The monitoring systems informs the plant personal overall plant behavior and historical data .this data allows the plant management, operator and maintenance personnel to take decision in regard to:-

Scheduling of further plant output Operation of plant Recording pf plant operational data Scheduling of plant maintenance outage The plant monitoring system provides via CRT, printer, hard copy unit or plotter, plant real or non real time data or calculated data, such as:-

Plant efficiency Life time calculation and monitoring Early detection of beginning deterioration of process components These data are indicated in either tabulation, bar chart, curves or mimic display form.

3. Engineering station: It has CRT, keyboard and printer as interfacing unit. The programming, fault checking is done in this station.

Man Machine Interface

Display Keyboard

Printer

Operating

StationOperating

StationOperating

StationEngineering

Station

Intra Plant

Plant Monitoring System

SYSTEM PROGRAMMING

PROCONTROL P system programming language technique has been designed to offer a simple way to power plant personnel to program, configure and maintain the entire control system. The programming technique is based on user-oriented language either using standard control symbols or filling the blank technique. This technique combined with PROCONTROL P hot repair capability and modular concept allows the power plant personnel, having no background in microprocessor of computer language, to maintain the control system on 24hr bases. Only complex calculation functions such as efficiency calculation require computer language knowledge. There calculations are a part of the plant monitoring system, which has no process\plant control or protection function. Possible program failure would not have any impact on plant or control availability. The control automation part of PROCONTROL P offers two basic ways to write programs:-

On a listing basis On a functional diagram basis These programs can be written on a CRT\keyboard station e.g. the engineering station. The programming and testing tools help in program code generation, diagnosis and trouble shooting of PROCONTROL system. The tools are classified in to three categories:-

1. Programming kit2. Indication and simulation devices3. Service kit

1. Programming Kits: These kits help in initial program generation, modification, editing and documentation. FUP & BUS ADMIN packages come under this category. The programming case serves for generation and/or modification of any programs in two or four digit hexadecimal code. The programming language P10 is written in this code. The generated code may be:

Written into a PROM/EPROM. Loaded into a test memory. Read out by way of an RS232 interface to a printer, cassette unit, a

processor etc.

2. Indication and Simulation Devices: These devices help in signal indication and signal simulation. The module 70SL01 belongs to this type. The test module for signals can receive any data word from the P13 local bus or send a data word to the local bus. Each bit of the data word is indicated with a lamp. Each bit is set with a switch for transmission. This module can be inserted into any free slot in the P13 local bus rack. The desired address is adjusted by means of the 2 digit-coding switch.

3. Service Kits: The service kit facilitates generation, modification of programs, indication and simulation of signals and parameter indication and adjustment. All programmable modules of P13 have interface through which the service kits can be connected for online modification/adjustments. SK03, SK04 &SK06 belong to this class.

ENGINEERING PRACTICE IN PROCONTROL P

Analysis of power plant process indicates the advisability of dividing the complex overall process into individual sub processes having clearly defined process functions. This provides an insight into the interdependency of the sub processes and their dependency upon associated individual subordinate functions. This division of the process into the clearly defined results in a horizontal and vertical organized hierarchical process structure. Whereas the hierarchical structure in the horizontal direction is determined by the number of drives i.e. the size of process, in vertical direction there are basically three hierarchical levels, these are being the

Individual control level Group control level Process control level

At the individual control level, there are equipment drives. The individual control system is located at the intermediate level. The group control level comprises the individual process unit and their drives. A group is that part of the process that fulfills a particular clearly defined autonomous task, e.g. the feed water supply of the feed water. At the process control level, all control groups interact for controlling the overall process. To guarantee that high quality engineering is performed in an economical way two engineering steps are followed: First step is mainly process oriented and performs all activities to

establish final function control diagram and user programs stored in EPROMS inserted in the processing modules of binary and modulating control.

Second step is hardware oriented and performs all activities necessary for the production of the control and monitoring system P13 as well as programming of the bus oriented signal marshaling. This takes care of all planning activities of locating the process cabinets in the plant and the control cabinets at the electronic room, control room and MMC.

HARDWARE DESCRIPTION

The hardware description of the PROCONTROL P is as given below:

1. Input module: The input module serves for the connections of 16standardized electronic module outputs. These modules should only be used for the acquisition of contact states from clean rooms and over short distances. The module may be plugged into any station of PROCONTROL P13 local bus. The module transmits the binary input signals in the form of telegrams via the local bus. Connected contacts are supplied from the module with the +24V operating voltage. Disturbances in the processing section are indicated as alarm fault indication by means of light emitting diode located on the module front plate and a fault indication signal SME1 is furthermore available at the module connector. The processing section continuously supervises the reception of the address. A fault-indicating signal will appear at the output SME1 is if the module address will not appear for more than 70ms on the local bus. The module transmits its data to the local bus by way of its standard interface to the local bus any time, when the address adjusted at the module appears at the local bus. Data transmission takes place in serial mode, and thus the processing section performs a parallel/serial conversion of data. The module address is adjusted by means of two coding switches A and B.

2. Output module: The output module serves as the purpose of controlling electronics module inputs, relay and lamps by means of potential-free contacts. The module may be plugged into any station of the PROCONTROL P13 system. It comprises a standard interface to the PROCONTROL P13 local bus. The module receives the signals to be issued in the form of telegrams from the local bus. The telegrams are checked in respect to validity before they are forwarded to the output circuit. the 16 output signals are forwarded to the output section. An output register with 16-memory location is provided. The register stores the values until the next output cycle from the PROCONTROL P13 local bus takes place. The module address is set by means of a code switches A and B.

3. Drive Control module: It is a compact drive unit with all the necessary connections to the control room and to the process. It is made up of a processor for binary and analog control task, programmable able in the PROCONTROL P10 programming language. The drive control module operates on a PROCONTROL P13 local bus, serving for the exchange of data with other P13 modules. The coupling to the local bus provides an exact representation of the local bus data in a data memory as well as output the calculated data to the local bus. The arithmetic unit cyclically executes the user written program according to the instruction list. The arithmetic unit is there by interrupted briefly by the local bus coupling, in order to permit the exchange of data with the local bus. A service program, which will be executed before the instruction list, scans the modules inputs.

4. Processing module: This memory module finds its application in the PROCONTROL P13 Diagnostic station. This memory module is implemented in the microcomputer sub rack. It consists of the 16-bit TMS 9900 microcomputer, a synchronization circuit for the interrupts, a start circuit and a memory field. The microcomputer sub rack bus is connected via additional line drivers and transceivers. The CPU clock frequency is 3MHz. The memory field can be configured to a maximum of 16K*16 bits and consists of low byte segment as well as high byte segment. Either RAM or EPROM memory can be implemented.

PUNJAB ENGINEERING COLLEGECHANDIGARH

Progress report on Industrial Training of B.E. student (To be filled by the section in In-charge). The student will submit the completed from in the Training and Placement Cell.

Name of the industry :

Name of the student :

Branch :

Year :

Period of Training : From To

Interest in work assigned Very Good/Good/Average

Capacity of work and intelligence Very Good/Good/Average

Punctuality and regularity Very Good/Good/Average

Remarks (over all impression):

Signature of Section Incharge Designation Official/Industrial Seal

RECORD OF ATTENDANCE

Period From ToName of studentNumber of working daysDays attendedAuthorized leaveDays of Absent

Signature of Section Incharge Designation Official/Industrial Seal