15-05-2012, 01:04 PM
SCADA for Thermal power plant.
SCADA FOR THERMAL POWER PLANT SYNOPSIS.docx (Size: 2.43 MB / Downloads: 116)
Abstract :
In earlier days distributed control systems were in use. In general DCS focused on automatic control of a process usually within a confined area. The DCS is directly connected to the equipment that it controls and is usually designed on the assumption that the instantaneous communication with the equipment is always possible. DCS often operates with a “state” paradigm: the system relies on the ability to obtain an immediate view of the current state of the system at any time.
a. DCS was very expensive.
b. It use to have more hardware parts and accumulate more space.
c. Maintainance cost was more.
d. System was not reliable in certain times.
These drawbacks led to the need for new process control system. In 1970’s a software called as SCADA was been developed this had an added advantage of monitoring the system with controlling features.
Introduction:
SCADA in thermal power plant is required to overcome the drawbacks of semi-automated thermal power plant. SCADA is implemented in the thermal power plant by having the corresponding control mechanism on each element of the plant whose output is given as input to the sensors connected to the particular element. Further, these sensors collect the information from the element and provide it to the corresponding RTU. These RTU’s further communicate with master station to update the process flow. This is how the SCADA with help of sensors, RTU’s and PLC’s not only controls but also monitors the system.
Supervision and control of the process:
a) Supervision of the natural gas:
Natural gas is the fastest growing primary energy source in the world. It is one of the popularly used fuels in the TPP. In thermal power plant , the gas undergoes several operations of preparation before being introduced in the steam generator, it must be filtered, rehash, relaxed and counted.
The different stages of interfacing and configuration of a natural gas counting system to the SCADA system are:
(1) The branching of the counters gas lighter to the SCADA system;
(2) The programming of the general counting of the gas lighter;
(3) The configuration of a new tabular circuit of the natural gas containing the new information.
We choose the input/output map, the programming and the necessary block. This operation is achieved by the standard algorithms. The proposed solution is to make the counting of impulses by the SCADA system and to program blocks of hourly and daily numbering. These impulses are given out by the generator of meter impulses to turbine.
The meter to turbine of gas lighters is installed 7.5 ms of the steam at the level, the distance between this one and the SCADA system is appraised to 160 m, the work of branching are done during the minor revision of the power station. After these works of branching, programming of the different blocks of counting of the volume gas lighters. An algorithm of numbering of the volume of natural gas has been adopted. Indeed, the AIN block permit the reading of the raw value (0 to 65535 points) a way of entrance of a module FBM217 that achieves then on a read data of conditioning functions (characterization, stake to the ladder, limitation), of filtering and alarm. The ACCUM block achieves the integration and delivers to OUT exit a quantity. The block MATH permits to achieve some arithmetic operations in definite chain in a program. For the stage of configuration, we use the ICC(Integrated Control Configuration) software. This last enables us to create and to configure programs residing in the CP60. A new display was elaborated using the Fox Draw software containing the new counters of the natural gas of the TPP