Discussion on the control and structure of sewage

A brief talk on the control and structure of sewage pump station automation system

the sewage pump station automation system in most sewage treatment plants in China mainly adopts the distributed calculation based on programmable logic controller (PLC), otherwise the cooling speed is accelerated by the machine monitoring system. The configuration of PLC is flexible and has strong safety, reliability and adaptability. However, there are also some problems in the pump station using the automatic system at present, such as the imperfect overall system, unreasonable function design, lack of equipment maintenance measures, and the lack of technicians, which make it impossible to play its function in actual operation

1. Problems in the control and structure of the sewage pump station automation system

1.1 the liquid level is unstable

the sewage pump station used in some cities is started by the pump controlled by the liquid level meter. When the sewage enters the pump station, the water level is unstable. Under the influence of the unstable water level, the pump will start continuously, pause continuously or start and stop continuously. This situation will affect the stability of the operation of the sewage pump station and shorten the service life of the pump station

1.2 the utilization rate of the standby pump is not high

under the use of the sewage pump station automation system, each pump station is equipped with a standby pump. The function of the standby pump is mainly to ensure the normal operation of the pump when the pump needs repair or maintenance in case of failure, without affecting all links of sewage treatment. If the standby water pump is not used for a long time, the standby water pump in the water collecting well may reduce the insulation resistance of the motor of the operating system and reduce the service life of the sewage pump for a long time

1.3 the increase of water level of the water collecting pump is unstable

the precipitation changes with the seasons, and there are obvious differences in the precipitation in different seasons. The water level in the pump pit of the sewage pump station is affected by the change of water level. For example, in the rainy season, the water level of the water collecting pump increases too fast, which is easy to cause the interval of each start-up of the pump to be short, and the instantaneous current caused by the start-up in a short time is too large, which is very easy to cause the tripping failure of the distribution cabinet

1.4 problems caused by manual control

at present, some sewage pump stations still use the traditional manual control method on the opening and closing of valves. Due to the influence of manual negligence or other factors, in the valve control, the control will be delayed due to the experiment of personal drainage, including the tension, contraction, low cycle and high cycle fatigue of materials and parts, resulting in the problems of excessive water collection in the pump pit and high water level rise, and the pump room will be flooded in serious cases, Affect the normal operation of the pump station

1.5 the automatic control system is imperfect

some sewage pumping stations lack perfect control system lines, which can not fully protect the main settings of the system, affecting the function of the automatic control system. The maintenance work of the system equipment is not in place, resulting in the obsolete structure of the system grid, which is easy to cause the loss of important data between the pump station and the central control room, and affect the integrity and accuracy of automatic control data. In addition, the system lacks dynamic monitoring and management of the specific operation of the pump station, which is not conducive to the integrity of information

2. Control solution of sewage pump station automation system

in order to solve the current situation and problems of sewage pump station automation system in China, this paper proposes a sewage pump station automation system based on intelligent controller. Its main functions include pump station electrical quantity collection, water level collection, alarm, one key start-up, automatic start-up, remote control, etc. The conventional operation buttons of the pump station automation system based on the intelligent controller are consistent with the operation of the general control system, which is conducive to the rapid realization of the intelligent operation of operators

2.1 optimization of liquid level meter and water pump

set a new stop liquid level meter, install the stop liquid level meter below the original liquid level meter, reduce the impact of large water flow impact on the start of water pump at the beginning of water inflow, alleviate the frequent failure of water pump start, and thus improve the service time of water pump. The traditional sewage pump station mainly uses the liquid level in the pool to control the switch of the water pump, so the position of the water pump level gauge should not be set at the position where the water flow is fast and the maintenance is difficult, which is conducive to reducing the start-up failure of the water pump caused by the excessive water flow, and also convenient for the maintenance and repair of the level gauge. Reasonably set the water level for the start and stop of the water pump, avoid equipment failure caused by frequent start and stop of the water pump, and improve the service life of the equipment. Only when the water volume of the sewage pump station is too large in the rainy season, all pumps will operate at the same time. The operation time of each pump at other times should be balanced and reasonable to ensure that each pump operates alternately and improve the utilization rate and service life of each pump

2.2 central control system

the controller of the automation system of the sewage pump station is set in the conventional electrical cabinet. The two are integrated, eliminating the steps of setting a separate control cabinet, effectively saving space and wiring. The core of the system is the controller. The intelligent system of the pump station is mainly composed of incoming cabinet, pump control cabinet, reactive power compensation cabinet, station power distribution cabinet, safety prevention system, etc. Among them, the functions of the incoming starting cabinet mainly include connecting to the main incoming power supply, incoming relay protection, intelligent control of the pump station, collection and exchange of information and data, operation status, parameter reminder, etc; The functions of pump station control cabinet in the whole system include automatic start and stop, relay protection of motor, operation status and parameter reminder, etc; The power distribution of the pump station is completed by the station power distribution cabinet; The safety prevention system can ensure the safety of the system and play the role of warning signal. We should strengthen the update and improvement of the system software, and automatically improve it from its integration level; When the speed drops below 70km/h, the hardware equipment of the system is regularly maintained and the version is sampled to ensure the smooth operation of the automation of the sewage pump station

2.3 transformation of electrical equipment and lines

in the transformation of electrical equipment, the focus is to add the functions of grid over-current and over torque protection and alarm in the system control box to ensure that the grid failure will not have a huge impact on the operation of the water pump. In addition, it is also necessary to strengthen the independent control of the grid. The pump control motor is prone to excessive current fault, so the current detection instrument of the line can be added in its main circuit to ensure the smooth operation of the overcurrent. An intelligent power detection device is set in the low-voltage operation cabinet, which is connected in series to the system server network to monitor the main power at the low-voltage side of the pump station. In terms of the control circuit of the pump station control system, we will focus on the maintenance and transformation of the line, check the setting of the main circuit, control circuit, signal circuit and other wiring one by one, and reduce the line transmission problems caused by the electromagnetic interference between lines. We should increase the centralized control capability of the whole equipment, and focus on the transformation of equipment without centralized control function

234 automatic monitoring system

the sewage pump station automation system uses advanced pump station expert control system technology, which can continuously improve and optimize the combination of pump unit equipment according to the data information such as the environment and the operation changes of pump unit equipment, realize the role of energy conservation and consumption reduction by increasing the utilization rate of equipment, and improve the economic benefits of pump station operation. The automatic control system of the pump station also uses the safety prevention technology of the pump station, which can intelligently identify and detect safety faults; This technology can automatically detect whether the management area is safe before starting up. If there is an unsafe fault or situation, the system will automatically shut down the pump set and send a warning signal to ensure the safety of staff; During the unattended period, the automatic detection function is used to ensure the safety of the area and prevent the loss and damage of property and equipment. The intelligent system of the pump station also uses the advanced technology of wireless customized on-demand and push of hot spot data of the pump station. The system management and operators can use the network to understand all kinds of hot spot information in real time, realizing the intelligent and network management of the pump station; The system uses advanced cloud computing technology to effectively improve the intelligent management level and system operation efficiency, and save management costs. The operation of the pump station automation system is basically the same as the conventional operation, and its button settings are consistent, so as to promote the operators to be proficient in intelligent operation as soon as possible and avoid the system operation failure caused by personal factors

in a word, modern sewage pumping stations are widely used in urban sewage treatment and are closely related to production and life. The improvement of the automation system of the sewage pump station is conducive to the safety and stability of the operation of the sewage pump station. The inertia cover and pulley cover should be opened regularly to remove the ash outlet under the flange, and the modernization of the management of the pump station can be realized. With the development and improvement of automation technology, the automatic control system of pump station can integrate control, operation and management, and realize the automation and intellectualization of pump station control. Therefore, it is necessary to strengthen the research and improvement of the problems in the control and structure of sewage pump station automation system, use advanced intelligent control technology to realize the automatic operation of sewage pump station operation management, and ensure the safety and stability of pump station system equipment