The centralised heating system has merits such as having high heat efficiency, energy saving, minimal pollution, and excellent heat supply efficiency. Going forward, the development of heat supply equipment will move in that direction, whereby the waste heat of the thermal power plant will be reused. The thermal power grid monitoring system comprises a primary grid system, secondary grid system, constant pressure water replenishment system, and heat measurement system. These equipment are also inter-related and there is inter-equipment interaction. The heat source enters the heat exchanger via the primary grid supply pipeline. Once it passes through the heat exchanger, it flows back to the heat source via the primary grid return pipeline. The secondary pipeline’s water enters the radiators of heating users via the secondary grid supply pipeline after the water has gone through the process of heat exchanging. Once the user obtains the heating, it re-enters the heat exchanger through a secondary grid return pipeline, circulating in this manner to provide the user with heat.
In the heat supply industry, HollySys is able to provide an integrated solution including control solutions for the heat boiler plant and heating grid heat exchange station. The company’s LK series PLC products have been successfully implemented in many heat exchange stations.
The heating plant auxiliary system comprises a bunker coal transport system, trestle coal transport system, and a boiler slag removal system. The HollySys LK series PLC is separately used for the integrated control, monitoring, and management of each sub-system, and connected to the heating plant boiler’s DCS control system. This method of “integrated monitoring and distributed control” results in the monitoring and automatic control of the production equipment and processes of the heating plant boiler auxiliary system. It completely satisfies the requirements for the heating plant’s auxiliary system to be safe and operating effectively, providing users with a type of low-cost and highly reliable control solution.
The heat supply dispatch and monitoring system monitors, controls, interlocks, sends alerts, and prints reports pertaining to the heat exchange stations’ process parameters, electric parameters, and the equipment operating status, whereby completing the necessary schedule control, time control, circuit control, and host computer monitoring, and management roles for the whole heating grid dispatch process. The whole system comprises a dispatch centre, communication transmission section, and a heat exchange station. The site monitoring equipment PLC mainly completes the real-time acquisition and control of the heat exchange stations’ different operating equipment and process parameters such as the primary and secondary grid’s temperature, pressure, flow, and water level, and send the heat exchange stations’ operating status data to the scheduling centre, and also receive the dispatch control orders issued by the dispatch centre. The dispatch centre is in charge of accepting data sent from the different site monitoring equipment, which will be saved, and the historical trends of such data will be analysed. Alerts reports will be sent if necessary and reports will be printed. Based on this, the dispatch control orders will be issued to the different field equipment.
The remote meter reading system supports the automatic computer meter reading, which is suitable for the construction of new districts and the revamping of existing districts. It possesses characteristics such as functional reliability, accurate measurements, ease of installation, effective functions, and widespread applicability, and thus is able to satisfy the different management requirements of thermal power companies. The employees of the management department need not leave their office for site visits. They will just need to use the computer’s control system, connect it directly to the GPRS network so as to accurately read the heating meters of the residents in the districts under their jurisdiction, for which management and control will be exercised.
The smart remote meter reading management system of HollySys can be divided into 4 portions.
Dispatch management system: It comprises a dispatch centre, communications network, and field monitoring station. It monitors, analyses trends, controls, interlocks, sends alerts, and prints reports on the process parameters (temperature, pressure, flow etc.), electrical parameters, and equipment operation status, thus fulfilling the necessary roles of data acquisition, data communication, and host computer monitoring and management for the whole heat supply schedulingdispatch process.
GPRS network data transmission: Once a single station’s GPRS DTU receives the PLC data, the GPRS service network is used to send these data to the central station’s operator computer.
Field acquisition equipment: The field acquisition equipment comprises mainly the M-BUS hub and PLC control system. The main function of the M-BUS hub is to carry out the PLC’s data acquisition from the different heating meters. The main role of the PLC control system is to acquire in real time process parameters of the heating users such as temperature, flow, and heat, and reflects and controls the operating status of the equipment. With support from the communication network, the field monitoring station sends data about the operation status of the heat exchanger to the dispatch centre, engaging in data communication and data exchange with the schedulingdispatch centre. If the dispatch centre’s monitoring computer were to encounter a failure, is not in use, or there is a fault in the communication network, the field measuring and control level shall continue to operate normally, and this will not affect the field equipment.
User-end heating meters: Mainly used in measuring parameters such as the accumulated flow and heating volume of the heating user.