Application of the wireless centralized monitoring system in the well group of the water source of Zhangjiakou Power Plant
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1 Overview
Zhangjiakou Power Plant is the main power supply plant in Beijing, with 8 300MW generating units. A total of 26 wells in the first and second phases of the water source were put into operation in 1989 and 2000 respectively, providing water for power generation by 8 units and water for fire fighting, production, and daily life of the entire plant. The normal operation of the water supply system equipment in the water source is a major issue directly related to the safe power generation of the entire plant and the livelihood of the entire plant’s employees. Reliable start-stop control and timely and accurate feedback of various parameters are important guarantees to ensure the safe and stable operation of water supply equipment. The start-stop control and current feedback equipment for the well location of the water source are all technologies and products in the early 1980s, some of which are cable control, and there are many problems in many aspects of the system structure. Coupled with the poor quality and low insulation strength of the equipment itself, it has caused multiple electrical accidents. The main problems are as follows:
1. The well positions of the water source are geographically dispersed and have long distances in space. The existing 20 well position control systems use long-distance overhead cables for remote control. The longest control cable is about 5.05 kilometers. Due to the long cable distance and the wind and sun , The aging condition of the control cable is extremely serious. Due to the aging of the cable insulation, one pump is started, multiple pumps are started together, and one pump is stopped and multiple pumps are connected. Due to the complex ground conditions that the secondary cable lines pass through, they are often damaged by lightning, resulting in failure of deep well pump control.
2. At present, due to severe damage to the insulation of the control cable, there is no spare channel, and the cost of re-laying the control cable is relatively high. In addition, there are still 6 wells that cannot be remotely controlled, and operators need to be on-site to start and stop operations. Faults often cause skipping trips, which seriously affect the safe operation of the unit.
3. I don’t know if the pump is down and the pump motor is running out of order. After the transformation, the response speed to this has been improved.
4. The various operating parameters of the well site cannot be monitored except for current. After the equipment is modified, the operating conditions of the well site motor current, voltage, temperature, pressure and flow rate will be monitored.
5. The mechanical and electrical equipment in the central pump room (10KV section, 380V section, electric valve at the outlet of each booster pump) has not been monitored yet. After the transformation, this part is merged into the overall monitoring system.
6. The factory has a traditional way of understanding the operating status of the equipment at the water source (by telephone inquiry). After the transformation, the network computer of the factory can query the operating status of the equipment at the water source.
2. Transformation plan
(1) Introduction
The water source well group monitoring system adopts the DT-MCS remote measurement and control system of Beijing Datang Xingye International Control Technology Co., Ltd. This system is a high-tech remote measurement and control system integrating sensing technology, automatic control technology, wireless communication technology, and network technology. The system can successfully solve the inconvenience and danger of manual remote start and stop of water source well pumps, and at the same time greatly improve the measurement accuracy, so that operators in the central pump room can intuitively monitor and control the operation status of each well position pump at the water source site at any time through the computer . Fundamentally solve the problem that the operators have worked for many years-the pump is not known, and the transformer is stolen without alarm; in addition, through the laying of optical fiber cables from the water source to the production plant, the operating parameters of each well at the water source can be transmitted to the plant. The network control center, the network control personnel can control each well position of the water source area according to the situation and through the setting of authority, and improve the automatic operation and management level of the entire system of the water source well.
(2) System structure, working principle and realization function
1. System structure
The central pump room of the water source is the control center of the system. The central main station is composed of industrial computer, system monitoring software, and network access equipment. China Mobile’s wireless data transmission equipment realizes point-to-multipoint communication, which ultimately realizes remote centralized monitoring and control of pumps at various well positions.
Schematic:
2. The working principle of the system
Install a remote remote control box at each well of the water source. The core equipment in the control box is RTU (Remote Terminal Unit) and DTU (Data Transmit Unit). RTU collects field equipment information, and DTU transfers this information from the control box to the mobile public network. And the Internet, and finally transmitted to the pump room monitoring server, the server will store, analyze, forward, and output the information obtained. The normal system operation is in the client terminal of the pump room and the client terminal of the network control.
3. The system’s data center network access method
The selection of the data center part of the network access mode occupies a particularly important part in the implementation of the entire wireless ultra-long-distance measurement and control system. If you choose it well, you will get twice the result with half the effort.
1). The network access method of the first phase (only 3 pumping stations were used in the first phase)
For the first phase of no optical cable access plan and no direct dial outside line in the pump room (access to the direct dial line requires a few kilometers of telephone line from Netcom), after negotiation, we adopted China Mobile’s GPRS APN service.As shown below
APN (Access Point Name), namely “Access Point Name”, is used to identify the type of GPRS service. Each wireless device in this system has an APN wireless network card inserted, so that each set of card-containing devices has a fixed IP address in the mobile public network. Because the khaki IPs with the same access point name are under the same network segment, the data center can realize point-to-multipoint serial port transparent access to each lower-level site.
After adopting this method, the system solves the problem of inaccessibility to the wired network of the data center, and makes the water source system form a small local area network in China Mobile’s public network. The internal and external isolation ensures the safety of data and the stability of the system.
2). Phase II network access method
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