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外文文献：

Design and Implementation of Heat Exchange Station Control System

Keywords:Heat exchange station, Control system, PLC, Inverter, Configuration software.

Abstract.This paper introduces a design and implementation of heat exchange station control system

based on PLC and industrial configuration software, which includes the contr ol scheme and principle,

hardware selection and software design, etc. The circulating pumps and re plenishing pumps in the

system can all be driven automatically by PLC and inverter. Main process parameters, such as steam

pressure and measurement temperature and so on,can all be shown on the industrial PC running

configuration software, and instructions could be sent by the engineer and operator on-the-spot via the

Human Machine Interface as well. The automatic pressures adjustment of stea m supply of the heater

by advanced PID algorithm has been realized finally. It is verified that the system is highly reliable

and stable, and it greatly enhances the level of automation and pressure control accuracy of the heat

exchange station and meets all the equipments running demands well. Introduction

With the rapid development of economy and society, heat supply systems are the key power source in

the communities and plants in China. As a media between heat sources and heat loads in the systems,

a heat exchange stations plays a very important role for the heat supply

quality. Traditionally, most of

the pumps in the heat supply systems are operated by valves manually, s o it could bring about the

power energy consuming, high labor intensity and low operation automation. I n this paper a design of

control system for heat exchange station based on PLC, inverter and indust rial configuration software

was proposed,accordingly the aim for power energy saving,hi

gh heat efficiency and operation

automation has been achieved.

Process outline and Control demands

Process outline.The process outline and control demands were put forward at first before the scheme

and design of heat exchange station control system were proposed.

Heat exchange station consists of a steam-driven heater,plus3ci rculating pumps,2replenishing

pumps and electric control valve. By adjusting the steam flux into the mixture of water and steam

according to the temperature sensors mounted indoors and outdoors, the pr ocess of heat exchange

could be completed. Among these equipments, the steam-driven heater, a heat exchanger containing

mixture of steam-and-water, is the key appliance for heat supply system.

Control demands.Major control demands for the control system were listed a s follows [1]:

(a)Pumps driving.Pumps include3circulating pumps(2

in operation,1for backup)and2

replenishing pumps (1 in operation, 1 for backup). Among circulating ones one is driven by power

frequency, the others are driven by variable frequency, with 75KW power ea ch; among replenishing

ones one is driven by power frequency, the other is driven by variable frequency, with 3KW power

each. The control signal should be originated from the pressure difference between the supply water

and return water.Pumps could be driven in stepless speed regulating when connecting variable

power;