1. Speed regulation and energy saving effect:
Since the centrifugal pumping station was officially put into operation, the working methods have also undergone great changes. The design head of the pumping station unit was 37m. When it first started operation in 1994, the speed-regulating unit was being debugged, mainly running the fixed-speed unit. After the debugging of the speed control unit is completed, the main operation is the speed control unit. In the initial stage, due to the small amount of water supply and the low elevation of the water supply point, the unit works in a state of low lift and large flow. At this time, the unit has low working efficiency and is far from the high-efficiency area. With the gradual increase of water supply, the pressure of water supply gradually increased, the working head of the unit was increased from less than 20m to about 33m, and the efficiency of the unit was greatly improved. Before December 1995, the working pressure of the unit was basically the same. We sorted out the power consumption per thousand m3 of water during speed regulation and constant speed work from the original report and listed it as Table 1. From January 1996 to September 1998 In between, the way of working has changed a lot. Since October 1998, the working state has been relatively stable. We selected the data from November 1998 to June 1999 and listed them in Table 2. In Table 1, since the speed-regulated unit and the fixed-speed unit work at the same time, we do not distinguish the unit consumption of water supply for a single unit, but only classify the speed-regulated unit and the fixed-speed unit for statistics.
It can be seen from the data analysis that when the water supply head is low and the unit does not work in the high-efficiency area, by adjusting the motor speed, the working point can be changed to improve the efficiency of the unit, so the energy saving effect is very significant, and the energy saving rate is as high as 40%; when the head After the improvement, the efficiency of the unit is obviously improved, and the unit basically works in the high-efficiency area, and the energy saving rate still reaches 25%. It can be seen that the energy saving effect of the speed regulating unit is very good.
2. System maintenance experience and problems:
During the construction of the pumping station, it suffered a once-in-a-century flood, and some equipment was once submerged by water. After the system was put into operation, many problems occurred, some were technical problems, some were equipment problems, and some were left over due to incomplete treatment after flooding. In the past five years, the equipment has been operating normally, and the problems that have occurred have been solved one by one. After five years of operation and maintenance, we feel that in order to manage this system, we must first have a skilled maintenance team. In September 1995, the 2?# unit broke down, and the equipment sometimes ran normally, sometimes tripped, and burned the control insurance. Each component is tested individually, and it is normal; after the DC power is turned on, it is found that the +5V power supply is abnormal. After analyzing the drawings and testing section by section, we finally found a relatively hidden place where a piece of metal scraps was placed between the two feet of the power board.
During the operation of the equipment, we found that there are still some problems in the system:
The system is more sensitive to lightning strikes, especially some electronic components. Shenzhen is located in the Dolei area, and the place where the pumping station is located happens to be the lightning strike area in Shenzhen. In August 1995, there was a lightning strike, the 3# unit tripped, the speed control operation screen was blurred, and the DC power was restored and reset to normal. The power factor of the crosstalk system is relatively low. According to our original records, the lowest is only 0.65. Therefore, it is necessary to install a local compensation device and a harmonic absorption device, but the harmonic absorption device is very prone to failure. Under the action of harmonics, the low-voltage transformer often has the phenomenon of burning. The thyristor element generates heat during operation, which makes the temperature inside the device very high. In summer, the Shenzhen area continues to be hot, and the temperature in the control cabinet is as high as 41 °C, which is not good for the work of the equipment, so the ventilation of the equipment is very important. Now, we remove a part of the surrounding glass, which can basically guarantee the work, but when the temperature is too high, we have to solve it by other means. In order to make the system run normally, in addition to cultivating a strong team in technology, there must also be a set of effective methods in management, and strengthen management.
(1) A file must be established for each device, and managed by computer, and various parameters of the device are regularly entered as historical data for analysis and comparison. Every time the equipment is overhauled, maintained, and components replaced, it will be reflected in the file in time, so as to be confident.
(2) Regularly clean the carbon brushes, absorb the carbon powder with a vacuum cleaner, check whether the wear amount and pressure of the carbon brushes are balanced, measure the length of the carbon brushes, and replace them in time when the length is less than the specified value.
(3) Regularly clean the filter screen of the thyristor cabinet. The blockage of the filter screen may cause poor heat dissipation of the thyristor element, resulting in the burning of the thyristor. The ABB serial modulation system has been running in our station for more than five years, and it is basically normal. The system has a certain advanced nature in technology, is more convenient in operation and management, and has obvious energy-saving effect, which has achieved the expected goal.
