I. Project Overview
my country's sewage pipe network automation technology started relatively late, and research on sewage pump station automation technology also lags behind developed countries. For a large developing country with severe pollution and limited resources, developing a sewage system that meets emission requirements, has good treatment effect, low operating cost, and is domestically produced with a high degree of automation is of great practical significance to economic development and also contributes to the country's energy conservation and emission reduction efforts.
Cixi City is located in eastern Zhejiang Province, northern Ningbo City, and on the south bank of Hangzhou Bay, with a total administrative area of 1,361 square kilometers. The city's sewage pipelines are divided into eastern, western, central, and central urban lines. In recent years, in conjunction with the Cixi Drainage Company's intensive pump station operation and management model of "on-site security and cleaning and automated control, and inspection, maintenance, and unified dispatching of the pipelines," a SCADA system has been designed and established for all sewage pump stations and sewage treatment plants within the city's jurisdiction. This system monitors the operational status of drainage pump stations and sewage treatment plants in real time. Based on this, a "pipeline intelligent dispatching" auxiliary decision-making system has been built to achieve automated control of pump stations, remote online control, unified dispatching of pump stations at all levels, and emergency linkage between the pipeline network and sewage treatment plants, maximizing economic and social benefits.
The project applies advanced computer control technology, programmable logic controllers (PLCs), industrial automation configuration software technology, and network communication technology. Combined with the existing characteristics of the sewage pipe network, it designs a high-performance and highly reliable sewage pipe network scheduling system that can automatically detect and control the operating status and parameters, has automatic fault emergency handling capabilities, and has network communication capabilities.
II. Project Design
● Establish a system that integrates monitoring, configuration, operation, scheduling, management, real-time data storage, historical data query, and system maintenance.
● Collect process parameters, electrical parameters, operating status of major equipment, and important environmental indicators of all sewage pumping stations and sewage treatment plants in Cixi City.
● To achieve automatic detection and control of the process and all operating equipment of all sewage pumping stations in the entire Cixi city area.
●Based on wastewater treatment plants as the basic unit, it can display the sewage trend map of the pipeline network by region, with dynamic parameter display, trend report display, and automatic generation of various reports.
● After long-term storage of liquid level data from each pumping station, the data will be organized and analyzed to provide a reference for the scheduling decision-making system;
● The alarm system will provide audible and visual alarms for various faults in the field equipment in the central control room, and can print out the faults according to the pre-designed categories.
● Gradually achieve the goal of "no one or few people on duty at the sewage pumping station" to reduce the workload and labor intensity of operators.
● By installing video surveillance and security equipment, the safety of process equipment and personnel within the pumping station is maximized.
III. System Architecture
The pipeline dispatch center is located in the pipeline operation department of Cixi City Drainage Company. It uses data servers and application servers to monitor and control the operation of all drainage pumping stations within its jurisdiction. The stations are distributed throughout the entire Cixi City area, and the hardware used includes various types such as Siemens S7-200 and S7-300 PLCs, Hollysys LK-210 and LK-207 PLCs, and Beijing Ankong PLCs. The system diagram is shown in Figure 1; the specific implementation details of the project are as follows:
IV. System Functions
The SCADA monitoring system software of the pipeline dispatch center adopts the eForceCon Server V2.0 configuration software from Beijing Sanwei Likong Company. It is installed on two operator station monitoring computers in a dual-machine redundancy mode, and connected to the PLC control system of each pump station via a 1000M fiber optic industrial Ethernet. The dispatch center collects the operating data of each level of pump station in real time and displays it in text or graphic form. The collected data is written to the databases of the data server and the modeling and calculation server. When the equipment is in "remote" mode, the start and stop of the equipment in the pump station can be remotely controlled through the operator station in the central control room. The analog parameters of the controlled objects are set with range limits, and an alarm is triggered when the range is exceeded. Important data is archived to ensure the reliability and safety of operation. Configuration reports are printed, and various operation reports of the pump stations are customized according to the operation management format requirements of the drainage company.
4.1 Monitoring of the process of the booster pump station; Figure 2 shows the main monitoring screen of the SCADA system, which is used to monitor the entire process of the sewage booster pump station. The monitoring screen displays real-time operating data of the pump station, such as changes in the liquid level in the pump pit, the operating current of the pumps, hydrogen sulfide levels, and pump operating time; it also monitors the operating status and real-time alarms of various equipment within the pump station, such as the start and stop of pumps, the start and stop of bar screens, the opening and closing of gates, and real-time alarm information for corresponding equipment malfunctions.
The main monitoring screen also provides connections to the screens of each sub-device. If you want to operate a certain device, you can switch to the monitoring screen of the corresponding device by using the switch button.
4.2 Remote monitoring of water pumps in the pumping station; In the main monitoring screen, switch to the remote control window of the water pump through the associated button, as shown in Figure 3, which is the control screen of the water pump in the pumping station; In the operation screen, you can select the operation mode of the water pump as "central control" or "automatic";
When "central control" is selected, the water pumps of the remote pumping station can be started and stopped using the "central control start" and "central control stop" buttons on the control screen;
When "automatic" control is selected, the water pumps in the remote pumping station can automatically start and stop according to the changes in the water level in the pump pit, based on the preset control mode.
4.3 Remote monitoring of auxiliary equipment within the pumping station; In the main monitoring screen, switch to the control screen of the auxiliary equipment via the associated button, as shown in Figure 4. In the operation screen, the current status of auxiliary equipment such as deodorization, bar screen, gate, and conveyor can be monitored; At the same time, the corresponding control mode can be selected according to the different processes of each auxiliary equipment.
The gate shown in the diagram only has a manual control mode. The gate in the remote pumping station can be controlled by the "manual open" and "manual close" buttons at the pipeline dispatch center. Other equipment has both manual and automatic control modes. When "central control manual" is selected, the start and stop of the corresponding equipment on site can be controlled by the "manual open" and "manual close" buttons of the corresponding equipment. When "central control automatic" is selected, the on-site equipment will operate automatically according to the preset operating mode.
4.4 Liquid level trend report query; Switch to the trend report query screen via the taskbar navigation button, as shown in Figure 5, which is the pump station liquid level trend query screen; The trend report can query the real-time trend and historical trend of liquid level, and can also display the liquid level trend of different pump stations in the same report for comparison and analysis;
When performing a historical query, first add the name of the pump station to be queried, then determine the start time of the query, set the query interval, and you can then query the liquid level trend chart of the corresponding pump station during a certain historical period.
4.5 Pump Station Linkage Function; In the previous operation mode, it was common for the level of the downstream pump station to reach the warning level in the same sewage transmission pipeline, while the upstream pump station was still pumping water. This often resulted in sewage overflow, backflow, and even flooding of farmland, which adversely affected the lives of surrounding residents and caused significant economic losses to the drainage company. Considering this situation, a pump station linkage function was added to the monitoring system. Figure 6 shows the sewage pipeline pump station linkage control screen. After the linkage function is activated, if the level of the downstream pump station reaches the warning level, the upstream pump station will automatically switch the pump to a stop state to ensure that the pipeline's water transmission capacity remains within the normal range.
4.6 Customizable Statistical Reports; The monitoring system can customize pump station operation reports according to the drainage company's operation and management format requirements, as shown in Figure 7, which is the shift section of the daily report for Western Pump Station No. 2. Customizable reports allow for data statistical queries in daily, monthly, and annual report formats, with query indicators added through configuration. The daily report query is further categorized by morning, afternoon, and evening shifts based on the actual operation and management of the pump station. The daily report shown in the figure includes indicators such as weather, liquid level, pump running time, and estimated power consumption. The summary of each shift report also shows the average change in liquid level in the pump station during the shift, the cumulative running time of the pumps in the pump station, and the power consumption of the pump station during the shift. The display style, format, and framework of the statistical reports can be customized.
4.7 Pump Station Information Management; Primarily used to manage the infrastructure data and operation and maintenance status of pump stations; During the long-term operation and management of pump stations, poor management due to personnel changes or other circumstances can lead to the continuous loss of initial construction information, gradually increasing the difficulty of later operation and maintenance. To prevent this from continuing, a pump station information management module has been added. Figure 8 shows the information management interface of Western Pump Station No. 4. System maintenance personnel can use this interface to enter basic construction information such as pump station address, scale, construction time, geographical coordinates, automatic control network/video address, pipe diameter, inlet elevation, and outlet elevation; When maintenance or repairs occur during normal operation of the pump station, the maintenance and repair status of specific equipment can be recorded.
4.8 Pipeline liquid level analysis function; it indicates that the operation of equipment such as pump start-up and shutdown, pump group switching, bar screen opening, valve opening and closing in the pumping station is closely related to the changes in the liquid level in the station, which shows the importance of liquid level in the process of improving the automated operation of the pumping station;
Figure 9 shows the monitoring system analyzing, comparing, and querying the liquid levels of each pump station in the same sewage pipeline according to the distribution of the sewage pipeline network. In the figure, the liquid levels of all pump stations on the same sewage pipeline are displayed in a three-dimensional and dynamic manner according to the Huanghai elevation standard, which helps the operation and maintenance personnel to analyze the real-time distribution of sewage in each pump station on the entire pipeline and make judgments for correct operation and management.
4.9 Alarm Query Function; Switch to the alarm query screen via the associated button on the main monitoring screen, as shown in Figure 10, which is the alarm query screen of the SCADA monitoring system; In the operation screen, you can select to view the historical alarm information of the corresponding booster pump station through the tree menu, and print the pump station alarm information as required;
4.10 Scheduling Function Description
To achieve production management and macro-schedule functions for pumping stations, intelligent control methods were used to optimize the control of the sewage network based on the dynamic changes in sewage flow and the changes in the water level of the pumping station's collection well, based on the SCADA monitoring platform. This enabled optimal regulation and control of the network water level, flow, and the sewage treatment plant's water receiving capacity, and effectively solved the problem of matching the transport flow of each sewage pipeline.
4.10.1 Scheduling Strategy: As shown in Figure 11, the system scheduling strategy is implemented by taking historical operating data of the sewage network and user scheduling instructions as inputs and outputting the optimal start/stop liquid level group for each pump station. After the scheduling decision instructions are sent to the LCS control system of each pump station, the LCS control system of each pump station automatically adjusts and controls the local submersible pumps according to the received optimal start/stop liquid level group. At the same time, the operating status information of the sewage network is fed back to the network scheduling center in real time through the monitoring system, which serves as a reference for further scheduling adjustments and data accumulation.
4.10.2 Scheduling Plan Configuration; Based on operational experience, the scheduling strategies required for sewage pipe networks vary depending on the season, time period, and climate conditions. Figure 12 shows the scheduling plan configuration window. Different scheduling strategies can be manually set and stored in advance according to the seasonal or climatic changes, such as normal scheduling, peak scheduling, off-peak scheduling, and thunderstorm scheduling. The set scheduling strategies are then integrated and added to the normal scheduling plan for execution. For example, when executing a daily scheduling plan, the day can be divided into several different time periods. By analyzing historical data as a reference, the start/stop liquid levels of pump units in the pumping station can be set for different time periods.
The scheduling strategy incorporates a weather forecast interlock function. When selected for operation, the scheduling plan can be determined based on the weather conditions in the next 6-24 hours. During the rainy season, sewage in the sewage lift pump station and sewage transmission pipeline can be emptied in advance, making full use of the sewage network's water storage capacity and transporting the collected sewage to the sewage treatment plant for treatment as much as possible, thus reducing the amount discharged into the river. The introduction of this function realizes a leap from automation to intelligence in pump station operation.
V. Project Summary
With the installation and deployment of eForceCon Server software, the control of pumping stations can now be managed centrally in the dispatch center. The SCADA monitoring system can remotely collect data and monitor the operation of equipment at all levels of pumping stations from the center. The dispatch management system processes, stores, and analyzes the collected data and sends it to the dispatch auxiliary decision module. The dispatch auxiliary decision module then performs reasonable dispatch management according to the sewage matching situation in the pipeline network and the pre-set dispatch plan.
The implementation of information technology infrastructure for the sewage pipe network and booster pump stations has truly realized an integrated dispatching model encompassing monitoring, management, and control. Since its completion and operation, the system has significantly improved the operational efficiency of the drainage company. It provides a clear overview of the pump station equipment's operating status, timely and accurate early warning information, and allows central dispatch personnel to monitor the work status of pump station staff and the on-site conditions of pump station facilities in real time. This not only solves the overall pipeline dispatching problem but also enables timely response to emergencies. While improving management efficiency, it minimizes risks and ensures the safe operation of the system, receiving high praise from users.
