In recent years, frequent urban flooding disasters in our country have caused severe casualties and economic losses, posing a significant threat to city safety. Data shows that from 2015 to 2018, the number of cities affected by flooding or experiencing internal flooding accounted for about one-fifth of the total number of cities in our country each year; there have also been significant losses of people's lives and property. Statistics indicate that as of the first half of 2021, 26 people have died or gone missing due to flood disasters in our country, resulting in economic losses of 13.5 billion yuan. On one hand, we need to actively construct and manage drainage facilities; on the other hand, we should establish a city flood control and drainage monitoring and early warning system. This system not only provides real-time information on river and road water levels for management authorities but also offers technical and data support for urban flood control management. The pump station remote monitoring system, based on technologies like the Internet of Things and edge computing, combines local self-control with a big data remote monitoring platform, providing solutions for urban flood monitoring, internal flooding early warnings, and treatment.
Classification of Urban Pumping Stations
City pump stations can be divided into three main categories based on application scenarios: drainage pump stations, sewage pump stations, and water supply pump stations. Drainage pump stations are primarily used for drainage and flood prevention; sewage pump stations are used to transport domestic wastewater; and water supply pump stations are mainly for urban domestic water supply. These three types of pump stations are crucial for the operation of cities, and ensuring their efficient, safe, and low-energy operation is a top priority for managers. The pump station management platform provides a solution for urban pump station management by integrating on-site monitoring and control sensors, edge computing, cloud platforms, and local PLCs.
Electrical Design for Urban Sewage Pump Stations
According to the DJG 08-22-2018 "Urban Drainage Pump Station Design Standard," drainage pump stations are typically powered by 35kV or 10kV, depending on power requirements and local electrical supply conditions. Urban drainage pump stations are classified as Class II load, with pump stations in important areas designed as Class I. Class II load stations generally require dual power sources with one as a backup, while Class I load stations need two independent power sources. In the event of a power failure, the alternate source can supply power independently. In special cases, a self-generated power source is also required. Taking a drainage pump station as an example, it is equipped with three 10kV high-voltage asynchronous motors and two 0.4kV asynchronous motors. Normally, the operation of the two 0.4kV motors is sufficient for drainage needs. During the flood season, up to five motors can run simultaneously, as shown in Figure 1.
The 10kV busbars employ single-busbar segmented wiring, while the 0.4kV busbars use either a single busbar or single-busbar segmented wiring. To minimize the impact of motor startups on the system, soft starters are utilized for motors with higher power ratings. The 10kV motors' reactive power compensation utilizes on-site compensation mechanisms, ensuring a power factor of approximately 0.95 post-compensation; for the 0.4kV motors, centralized reactive power compensation is employed, with a post-compensation power factor of not less than 0.9.
Pump Station Electrical Automation Second Design
3.1 The automatic control, measurement, protection, monitoring, and communication of pump station electrical equipment. This includes: high-voltage transmission and transformation systems at the pump station; 0.4kV distribution systems at the pump station; DC systems at the pump station; and the comprehensive protection system for motors. The configuration of the protection and measurement devices for the pump station is shown in Figure 2. All devices are equipped with communication interfaces and can be connected to the local monitoring system or regional pump station management platform through an intelligent gateway. The intelligent gateway is equipped with edge computing and logical control functions, enabling automatic control based on the actual operating conditions on site.
3.2 The automatic control, measurement, monitoring, and communication of pump stations and key auxiliary systems. This includes: control of oil systems for the main equipment (e.g., pump impeller regulating pressure oil system, rapid gate hydraulic (oil) control system, oil system, gearbox cooling oil system, etc.); control of gas systems for the main equipment (low-pressure gas system for vacuum breaker valves [suction pump stations], pressure oil system for pump impeller regulation, and medium-pressure energy storage gas system for other pneumatic tools); water system of the pump station (cooling water system, pump station drainage system, and fire-fighting water system for the main equipment set).
3.3 Automatic measurement, monitoring, and communication in various non-electrical fields. This includes: displacement, settlement, uplift pressure, and stress monitoring in hydraulic safety; hydrological, water level, water condition, water volume, and water quality monitoring; various temperature and humidity monitoring; insulation monitoring; gate opening and load monitoring, etc.
These signals are output in both analog and digital form, with the collected signals being 4-20mA analog and digital signals. These signals are primarily collected by PLC devices for corresponding alarms and control, and the data can be uploaded to the pumping station management platform.
To enhance reliability, signal isolation devices are required to be added to 4-20mA or 0-5V analog signals to implement measures such as voltage and current limiting, as well as isolation, thereby increasing the system's anti-interference capability.
3.4 Full-site video surveillance system and video information upload.
Pump Station Management System
The pumping station management platform consists of local protection measurement and control devices, measurement and collection instruments, PLC automatic control devices, video security, local control systems, and regional pumping station management platforms. The platform enables data collection, operation monitoring, control adjustment, energy consumption analysis, accident early warning and alarm, event recording, and maintenance management for pumping stations within the area. This facilitates unattended operation and centralized maintenance management of the pumping stations, enhancing their operational reliability.
4.1 Pump Station Management System (On-Site Deployment)
The Acrel-2000M pump station management system is deployed within the pump station, providing comprehensive monitoring, control, and operational recording. It can promptly issue alarm signals during anomalies, ensuring the safety of pump station operations.
Pump Gate Panorama
A pump gate panoramic view assists users in comprehensively monitoring the full operation status of the pump gate, including both the inner and outer river water levels, the opening degrees of the regulating gates in the east-west direction, the opening degrees of the gates on both sides, the operating status of the water pumps, and the current.
Pump Station Overview and Single Line Diagram
Inspect the distribution and connection of the pump station's power distribution circuit, as well as the main electrical parameters. Key data includes: three-phase current, three-phase voltage, power, energy, power factor, and circuit name.
Regulating Gate Monitoring
Monitor the operation status of regulating gates, such as gate opening degrees, lock/unlock status, and simultaneously track the trends of both inner and outer river water levels, as well as the operation of oil pumps. Additionally, this functional module allows for remote control of regulating gates and oil pumps, and provides the capability to switch between remote and on-site control.
Pump Operation Monitoring
Monitor the operational status of pump systems, such as running, stopped, and protective device failures, and enable remote control of the pumps and interlock control of drainage and water intake. Prior to implementing the remote control function, select the remote control for the pump and the PLC control cabinet of the working gate. During the interlock of drainage and water intake, the system will issue commands to open the inlet gate until it is fully open.
Gate Monitoring
Monitor the operational status of work doors and oil pumps, such as running or stopped states, and remotely control them within this functional module.
Trend Curve Analysis
The system can monitor motor operating load curves, water level curves inside and out, etc., helping users analyze and record operational trends.
Additionally, the system features alarm functions for anomalies and report generation capabilities, enabling management to promptly understand the power station's operational status.
