Abstract: How to use frequency conversion speed regulation equipment to save energy is the issue discussed in this article. The control principle of parallel running pump and speed regulation strategy and the mathematical method of controlling are discussed. The power control configuration software + PLC + VVVF control technology is used to determine the quantification of economical operation of pump station. Keywords: configuration software PLC virtual water pump water distribution industry, booster pump station frequency control energy-saving technological transformation, after the operation, generally found in the use of the following problems: 1, to meet the user's water demand and ensure In the case of water supply pressure, when the pump group is connected in parallel, the pump saves little or no electricity; when a speed regulating pump is running, it saves little or no electricity. 2, when the conditions point, the pipe network parameters and other changes, and in the pumping station system to meet the conditions of work conditions, the speed control system often appear unstable operation, resulting in energy saving can not maintain the lowest unit power consumption value. In view of the use of the water supply industry, many people blindly regard the VVVF equipment as the energy-saving equipment. In fact, they have no clear idea about the VVF technology and there is no accurate measure of the energy-saving effect. In this regard, this article discusses the parallel pump, the unit with a reasonable operation and the use of speed control mode, the use of force control configuration software + PLC control technology to solve the pump energy-saving economic operation of the quantitative problem. First, the minimum energy consumption of the parallel pump combination with the operation and speed control mode of control theory 1, the control principle of the pumping station system process parameters (flow, pressure), equipment parameters (pumps, motors, speed devices) In the case, the least squares method is used to find out the functional relationship between HQs. By using the characteristic curve fitting method of parallel pump sets, a set of running collocation and speed regulation mode with the lowest energy consumption can be automatically found, that is, the optimized pump combination scheme Reasonable pump operating conditions stable operation in the efficient range). Of course, the optimal pump combination does not necessarily mean that each pump can achieve the optimal result. In this case, it means the overall effect of the optimized combination of pumps in a pump station. It can vividly indicate that each of the optimized combinations Pump combination of programs as a pump, pump combination scheme we call the virtual pump, and a virtual pump at a certain pressure and flow, using the least squares theory to calculate the virtual pump characteristic equation and characteristic curve as a standard, Find out the range of the virtual pump efficient area. When the operating point of the "virtual water pump" is not operating in the high-efficiency area, the control system can automatically adjust the operating conditions of the variable frequency pump according to the similar theorem of the pump speed regulation and the equivalent efficiency principle so that the dynamic operation of the virtual water pump Of the working point in the high-efficiency area, then the unit flow minimum energy consumption. In order to make the working condition point of the "virtual water pump" after the speed regulation run in a high efficiency area, the characteristic curve of the "virtual water pump" after speed regulation can pass the set parameters (flow and pressure) according to the similarity theorem and the equivalent efficiency principle Point, this point is the "virtual water pump" the best condition point. Second, the technical design and implementation 1, pumping station process and control flow 1.1 pumping station process Dongzhuang with our pumping station with direct pumping of a DN800 pipeline water distribution, the final distribution flow of 2100m3 / h, outbound Pressure is 0.39MPa. The main equipment are: 2 Japan MITSUTISHI F series inverter; 4 centrifugal pump, each pump equipped with a water outlet valve, a hanging solenoid valve; 2 vertical submersible pumps (drainage); 2 Vacuum pump (water pump vacuum hanging water). In addition, there are system-related automation instrumentation and more. Starting from the goal of saving energy and reducing consumption, the final pump set of water pump station is optimized and matched with speed control scheme. Water pump in the clear water level of more than 1.8 meters when the water level for the self-filling; 1.8 meters below the need for vacuum hanging water. The number of pumps to open and close stops, according to the water level of the pool, service pressure and flow parameters automatically optimize the combination and the pump running status through the PLC's I / O interface promptly sent to the strength control configuration software real-time database so that the duty monitor at any time Pump operation; drainage pump water level under the pits, vacuum pumps according to the requirements of the vacuum hanging water to determine the open, stop pump. In the electrical circuit, high and low voltage switchgear closures are manually operated, power and instrument data records are automatically transmitted, on duty personnel can see from the display in time for each virtual pump unit flow power consumption values ​​and other parameters. 1.2 pump control process pump station within the pump control, field manual control can be used, semi-automatic control, automatic control mode, run pump failure, the standby pump automatically open. Set the parameters (flow, pressure) of "virtual water pump". The display also shows the theoretical HQ characteristic curve and pipe network characteristic curve of "virtual water pump". According to the theoretical unit flow power consumption value corresponding to each "virtual water pump", select the "virtual water pump" scheme and output the selected scheme. Before the pump is started, the system will automatically check the state of the clear water tank, the pump stop status, the pump non-fault status, the pump running status, the inverter non-fault status and the valve position status signal. If it is not normal, The signal is normal, turn on the speed control pump and the constant speed pump in sequence, and automatically open the corresponding outlet valve. After the "virtual water pump" is operating normally, the "virtual water pump" theoretical characteristic curve can be monitored from the display screen and the actual dynamic state of the "virtual water pump" If the real-time unit flow power consumption of the "virtual pump" exceeds the theoretical unit flow power consumption, the system will make a sound , Light alarm signal, promptly notify the duty staff, with local control by the duty manual control to adjust, so that the "virtual water pump" operating point in the high-efficiency area. If any of the above signals are not correct, the pressure and flow in the pipe network can not be switched on even if the requirements are met. At the same time, an alarm signal is issued. In addition, each pump running real-time current exceeds its normal rated current, and delay 8 seconds, the fault alarm signal, and emergency stop pump. If the pump fails to press the program, the alarm. Each pump motor failure, can automatically shut down the corresponding valve, and issued a fault alarm signal, while the standby pump put into operation. PLC received the closure of the pump command, first shut down the corresponding outlet valve, the pump stopped running. Drainage pump control logic and high and low voltage power distribution monitoring parameters controlled by the PLC alone. 2, the software design and implementation of three, the application effect June 2000 after the measured data statistical analysis, we found that the use of independent control frequency conversion control technology, parallel pump operation, less energy, with no use of frequency conversion equipment. April 2002 After the use of configuration software + PLC + VVVF control technology transformation, the pumping station system to meet the working conditions, automatic frequency conversion system is stable, the long-term energy saving effect to maintain the lowest unit power consumption than the original frequency After the transformation of equipment saving about 30. IV Conclusion In summary, in the water supply industry, the use of self-controlled frequency conversion equipment is energy-saving, through practice, we believe that only the application environment, the object of control and by accurate theory of how much energy-saving potential, and then what kind of automatic control The greatest potential for energy saving in retrofitting projects and the system being stable and reliable with long-term energy-saving results remain the only objective we can achieve with the current information engineering technology to transform the traditional control process. References: ①training materials preparation group control configuration software instructions. Beijing three-dimensional control Technology Co., Ltd. 1999.07. ② training materials writing group OMRON PLC Programming Manual. Shanghai OMRON Automation Co., Ltd. 1997.05. ③ Jiang Jishen eds. Water supply industry automatic control system Hohai University Press 1999.12. ④ Liu Chichia. Establishment of Pumping Station Economic Operation Plan. Pump Technology, 1998.02. ⑤ Yu Ming, Fan Shu Chang. Centrifugal pump operating conditions parallel to determine the point. Pump Technology, 1999.02. ⑥ Han Dehong Sun Wenshen. Establishment of Shenzhen Special Economic Zone Raw Water System Dispatching Model. China Water Supply Review for Fifty Years, 1999.
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