Hydropower station air cushion type surge chamber air system air compressor selection method

Abstract

The invention relates to the field of water conservancy and hydropower engineering, discloses a method for selecting an air compressor of an air cushion type surge chamber air system of a hydropower station, and solves the problems of low equipment utilization rate and high investment and operation and maintenance cost of an air compressor selection scheme in the prior art. According to the scheme, the method comprises the steps that the expected number of inflation air compressors and the expected number of work air supply air compressors are calculated, and the standby number of the air supply air compressors is selected; and determining the number of the finally selected air compressors according to the expected number of the inflation air compressors, the expected number of the working air supply air compressors and the number of the standby air supply air compressors, and selecting the rated exhaust pressure of the air compressors by considering the air pressure loss of an air supply pipeline. The selected air compressors can be used for air inflation and pressure building and can also be used for air supply and pressure maintaining, so that configuration of the air compressors and accessory equipment of the air system is simplified, equipment arrangement and needed space are simplified, the equipment utilization rate is increased, and investment and operation and maintenance cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of water conservancy and hydropower engineering, and in particular to a method for selecting an air compressor (air compressor) in an air system of an air cushion type surge chamber of a hydropower station. Background Art

[0002] The air cushion surge chamber of a hydropower station is a water hammer and surge control engineering facility with excellent performance, which uses high-pressure air in a closed air chamber to form an "air cushion" to suppress the water level height and water level fluctuation amplitude in the surge chamber. The air cushion surge chamber of a hydropower station has significant advantages over conventional surge chambers in terms of ecological protection and investment. The use of air cushion surge chambers in hydropower stations with high head, small flow, and good geological conditions along the water diversion system can reduce the length of the construction road and reduce the difficulty of construction. It is not only beneficial to the protection of the ecological environment around the water diversion system, but also saves construction time and investment.

[0003] Since the successful application of air cushion surge chambers in Norwegian hydropower stations in the 1970s, my country began to use air cushion surge chambers in hydropower stations with conditions in the 1990s. At present, they have been successfully put into operation in hydropower stations such as Ziyili, Xiaotiandu, and Yamansu. With the advancement of science and technology and the improvement of ecological and environmental protection requirements, the innovative technology of air cushion surge chambers in hydropower stations will be promoted and applied in the increasingly advocated construction of environmentally friendly hydropower stations.

[0004] The air cushion surge chamber of a hydropower station needs to be inflated and pressure-built with an air compressor after the first filling of water or after overhaul. During operation, when the air pressure in the air cushion surge chamber drops due to air leakage in the air chamber or water hammer and surge waves in the hydraulic transition process, an air compressor needs to be used to automatically replenish air and maintain pressure. Therefore, the air system of the air cushion surge chamber of a hydropower station is the technical support and guarantee for the successful application and safe and reliable operation of the power station, and the air compressor is the key core equipment of the air system. It should be ensured that the selection method of the air compressor is correct, the parameters and number of the selected air compressor are appropriate, safe, reliable and economical, and can meet the needs of the air system for inflation and pressure building, as well as the requirements of the air system for automatic air replenishment and pressure maintenance.

[0005] At present, in the prior art, the selection scheme for the air compressor of the air cushion surge chamber gas system of the hydropower station is: calculate the productivity and number of the inflation air compressor and the productivity and number of the air supply air compressor respectively, and configure the inflation air compressor and the air supply air compressor and their auxiliary equipment accordingly. Since the inflation air compressor and the air supply air compressor operate in different time periods of the air cushion surge chamber respectively, the equipment utilization rate is low, and the investment and operation and maintenance costs are high. Summary of the invention

[0006] The technical problem to be solved by the present invention is to propose a method for selecting an air compressor for an air cushion surge chamber gas system in a hydropower station, so as to solve the problems of low equipment utilization, high investment and operation and maintenance costs in the selection scheme of air compressors in the prior art.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: The method for selecting an air compressor for an air cushion surge chamber gas system of a hydropower station comprises the following steps: S1. Calculate the expected total production rate of the air compressor; S2. Calculating the expected number of air compressors according to the expected total productivity of the air compressors and the productivity of a single air compressor; S3, calculate the expected total productivity of the air compressor when it is working; S4, calculating the expected number of working air compressors according to the expected total productivity of the air compressors and the productivity of a single air compressor; S5. Selecting the number of spare air compressors according to the desired number of working air compressors; S6. Determine the number of air compressors to be finally selected according to the expected number of inflation air compressors, the expected number of working air compressors and the number of spare air compressors: the number of air compressors to be finally selected = max (the expected number of inflation air compressors, the expected number of working air compressors + the number of spare air compressors); S7. Consider the air pressure loss in the air supply pipeline and select the rated exhaust pressure of the air compressor.

[0008] Furthermore, in step S1, the desired total productivity of the air compressor is calculated as follows: ; ; ; ;

[0009] in, is the expected total production rate of the air compressor, in units of , free air; is the air chamber control constant, in units of ; is the local atmospheric pressure, in m of water column; is the air chamber inflation time, in minutes, which should not exceed 21600 minutes; q is the air chamber leakage, in minutes , free air; The correction coefficient of the local altitude to the air compressor productivity is selected from the preset table of correspondence between different altitudes and correction coefficients; The absolute pressure of the indoor gas under the static working condition of the air chamber design, in m water column; The indoor gas volume of the air chamber under static working conditions, in units of ; The highest reservoir water level for normal power generation of the hydropower station, in m; The indoor water level of the air chamber under static working conditions, in m; is the local altitude, in meters.

[0010] Furthermore, the correspondence table between the preset different altitudes and the correction coefficients is shown in Table 1 below: Table 1 Correspondence between different altitudes and correction coefficients .

[0011] Furthermore, in step S2, the desired number of air compressors is calculated as follows: ;

[0012] in, is the expected number of air compressors, in units; is the expected total production rate of the air compressor, in units of , free air; is the productivity of a single air compressor, in units of , free air; Indicates rounding up.

[0013] Furthermore, in step S3, the desired total productivity of the air compressor when in operation is calculated as follows: ;

[0014] in, is the expected total production rate of the air compressor when it is working, in units of , free air; is the air chamber control threshold, in units of , is the absolute pressure of gas in the air chamber during air replenishment With gas volume The product of The unit is m water column, The unit is ; It is the air chamber replenishment time, in minutes, generally ranging from 1440 minutes to 4320 minutes.

[0015] Furthermore, in step S4, the desired number of working air compressors is calculated as follows: ;

[0016] in, The expected number of air compressors to be in operation, in units; is the expected total production rate of the air compressor when it is working, in units of , free air; is the productivity of a single air compressor, in units of , free air; Indicates rounding up.

[0017] Furthermore, in step S5, the number of spare air compressors is selected according to the desired number of working air compressors, including: If the desired number of air compressors is If the number is 1 to 3, select the number of spare air compressors 1 unit; If the desired number of air compressors is If there are 4 to 5 units, select the number of spare air compressors For 2 units; If the desired number of air compressors is If the number of air compressors is 6 or more, select the number of spare air compressors. For 3 units.

[0018] Further, in step S6, the number of air compressors finally selected is set to ,but An air compressor with the same model parameters can be used for both inflation and replenishment.

[0019] Furthermore, in step S7, the selected air compressor rated exhaust pressure is 1.0 MPa to 2.0 MPa higher than the maximum air pressure in the air chamber during the hydraulic transition process of the water transmission and power generation system of the hydropower station.

[0020] The beneficial effects of the present invention are: According to the characteristics that the inflation and air replenishment of the air cushion type surge chamber are respectively in different operating periods of the hydropower station, the present invention organically unifies the selection and configuration of the air compressors for inflation and air replenishment of the gas system and comprehensively considers them, and preferably selects an air compressor that can be used for inflation to meet the needs of inflation and pressure building of the gas system, and can also be used for air replenishment to meet the requirements of automatic air replenishment and pressure maintenance of the gas system, thereby reducing the configuration of the air compressor and its ancillary equipment of the gas system, simplifying the equipment layout and the required space, improving the equipment utilization rate, saving the investment and operation and maintenance costs of the air compressor and its ancillary equipment, and providing strong technical support for the successful application of the innovative technology of the air cushion type surge chamber of the hydropower station and its safe, reliable and economical operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a method for selecting an air compressor for an air system of an air cushion surge chamber in a hydropower station according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention aims to propose a method for selecting an air compressor for the air system of an air cushion surge chamber of a hydropower station, so as to solve the problems of low equipment utilization, high investment and operation and maintenance costs in the selection scheme of air compressors in the prior art. The core idea is: since the inflation and air replenishment of the air cushion surge chamber are respectively in different operating periods of the hydropower station, and the inflation air compressor and the air replenishment air compressor can completely use the same model parameters, based on this, the selection of the inflation air compressor and the selection of the air replenishment air compressor can be organically unified and comprehensively considered, and an air compressor that can be used for inflation to meet the needs of inflation and pressure building of the gas system and an air compressor that can be used for air replenishment to meet the requirements of automatic air replenishment and pressure maintenance of the gas system can be selected, thereby simplifying the configuration of the gas system air compressor and its ancillary equipment, simplifying the equipment layout and the required space, improving equipment utilization, and thus reducing investment and operation and maintenance costs.

[0023] The scheme of the present invention is specifically described below in conjunction with the accompanying drawings and embodiments.

[0024] Example

[0025] Taking the application of the present invention to a hydropower station as an example, the following method is used to select the air compressor in the air system of the air cushion surge chamber. The implementation process is shown in Figure 1 : S1. Calculate the expected total productivity of the air compressor: In this step, the expected total production rate of the air compressor is recorded as , the unit is , free air; Expected total compressor productivity The calculation is as follows: ; ; ; ; in, is the air chamber control constant, ; The absolute pressure of the indoor gas for the static working condition of the air chamber design is 474.4m water column; is the local atmospheric pressure, which is 6.9 m water column; is the air chamber inflation time, in minutes, using 21600 minutes; q is the air chamber leakage, , free air, selected by reference to similar projects; is the correction coefficient of the local altitude to the air compressor productivity, and 0.675 is selected according to the corresponding relationship table between different altitudes and correction coefficients; The indoor gas volume for the static working condition of the air chamber design is ; The maximum reservoir water level for normal power generation operation of the hydropower station is 3723m; The indoor water level for static working condition of the air chamber design is 3255.5m; is the local altitude, which is 3250m.

[0026] S2. Calculate the desired number of air compressors: In this step, the desired number of air compressors is recorded as , the unit is Taiwan; Expected number of air compressors The calculation is as follows: ; in, is the expected total production rate of the air compressor, , free air; is the productivity of a single air compressor, , free air.

[0027] S3. Calculate the expected total productivity of the air compressor when it is working: In this step, the expected total productivity of the air compressor during operation is recorded as , the unit is , free air; Expected total production rate of the air compressor during operation The calculation is as follows: ; in, is the air chamber control threshold, , is the absolute pressure of gas in the air chamber during air replenishment (unit: m water column) and gas volume (Unit: ) It is the air chamber replenishment time, in minutes, generally ranging from 1440 minutes to 4320 minutes.

[0028] S4. Calculate the expected number of air compressors to be used: In this step, the desired number of air compressors is recorded as , the unit is Taiwan; Expected number of air compressors to be used The calculation is as follows: ; in, is the expected total production rate of the air compressor when it is working, , free air; is the productivity of a single air compressor, , free air.

[0029] S5. Select the number of spare air compressors: In this step, the number of spare air compressors is recorded as , the unit is Taiwan; According to the desired number of air compressors 7 to 3 units, select the number of spare air compressors 3 units to 1 unit.

[0030] S6. Determine the number of air compressors to be selected: In this step, the number of air compressors finally selected is recorded as , the unit is Taiwan; Number of air compressors finally selected The calculation method is as follows: Take the maximum value of the expected number of charging air compressors (15) and (the expected number of working air compressors (7 to 3) + the number of spare air compressors (3 to 1)), that is, 15, which is the number of air compressors finally selected. These 15 air compressors use the same model parameters and productivity , free air.

[0031] S7. Select the rated exhaust pressure of the air compressor: In this step, the rated exhaust pressure of the air compressor is recorded as , unit is MPa; Select the rated exhaust pressure of the air compressor The method is: Since the maximum air pressure in the air chamber during the hydraulic transition of the water transmission and power generation system of the hydropower station is about 5.5MPa, and considering the air pressure loss of the air supply pipeline, the rated exhaust pressure of the air compressor of the air system is selected to be 7MPa.

[0032] According to the above scheme, the hydropower station air cushion surge chamber gas system of the embodiment of the present invention only needs to be equipped with 15 units with a production capacity of , free air, rated exhaust pressure of 7MPa air compressor, for inflation and replenishment, thus saving the need to configure 10 to 4 additional production capacity , free air, air supply special air compressor with rated exhaust pressure of 7MPa and its auxiliary equipment, simplified the equipment layout and required space, improved equipment utilization, saved equipment investment of approximately RMB 25 million to RMB 10 million and operation and maintenance costs.

[0033] Finally, it should be noted that the above embodiments are only preferred implementations and are not intended to limit the present invention. It should be pointed out that for those skilled in the art, several modifications, equivalent replacements, improvements, etc. can be made without departing from the scope of the present invention and the scope of protection of the claims, and all of these should be included in the protection scope of the present invention.

Claims

1. The method for selecting air compressors for the air cushion surge chamber gas system of a hydropower station is characterized in that: The following steps are involved: S1. Calculate the expected total production rate of the air compressor; S2. Calculating the expected number of air compressors according to the expected total productivity of the air compressors and the productivity of a single air compressor; S3, calculate the expected total productivity of the air compressor when it is working; S4, calculating the expected number of working air compressors according to the expected total productivity of the air compressors and the productivity of a single air compressor; S5. Selecting the number of spare air compressors according to the desired number of working air compressors; S6. Determine the number of air compressors to be finally selected according to the expected number of inflation air compressors, the expected number of working air compressors and the number of spare air compressors: the number of air compressors to be finally selected = max (the expected number of inflation air compressors, the expected number of working air compressors + the number of spare air compressors); S7. Consider the air pressure loss in the air supply pipeline and select the rated exhaust pressure of the air compressor.

2. The method for selecting an air compressor for an air cushion surge chamber of a hydropower station according to claim 1, characterized in that: In step S1, the desired total productivity of the air compressor is calculated as follows: ； ； ； ； in, is the expected total production rate of the air compressor, in units of , free air; is the air chamber control constant, in units of ; is the local atmospheric pressure, in m of water column; is the air chamber inflation time, in minutes, not exceeding 21600 minutes; q is the air chamber leakage, in minutes , free air; The correction coefficient of the local altitude to the air compressor productivity is selected from the preset table of correspondence between different altitudes and correction coefficients; The absolute pressure of the indoor gas under the static working condition of the air chamber design, in m water column; The indoor gas volume of the air chamber under static working conditions, in units of ; The highest reservoir water level for normal power generation of the hydropower station, in m; The indoor water level of the air chamber under static working conditions, in m; is the local altitude, in meters.

3. The method for selecting an air compressor for an air cushion surge chamber of a hydropower station according to claim 1, characterized in that: In step S2, the desired number of air compressors is calculated as follows: ； in, is the expected number of air compressors, in units; is the expected total production rate of the air compressor, in units of , free air; is the productivity of a single air compressor, in units of , free air; Indicates rounding up.

4. The method for selecting an air compressor for an air cushion surge chamber of a hydropower station as claimed in claim 2, characterized in that: In step S3, the desired total productivity of the air compressor when in operation is calculated as follows: ； in, is the expected total production rate of the air compressor when it is working, in units of , free air; is the air chamber control threshold, in units of , is the absolute pressure of gas in the air chamber during air replenishment With gas volume The product of The unit is m water column, The unit is ; It is the air replenishment time of the air chamber, in minutes, ranging from 1440 minutes to 4320 minutes.

5. The method for selecting an air compressor for an air cushion surge chamber of a hydropower station as claimed in claim 4, characterized in that: In step S4, the desired number of working air compressors is calculated as follows: ； in, The expected number of air compressors to be in operation, in units; is the expected total production rate of the air compressor when it is working, in units of , free air; is the productivity of a single air compressor, in units of , free air; Indicates rounding up.

6. The method for selecting an air compressor for an air cushion surge chamber gas system of a hydropower station as claimed in claim 5, characterized in that: In step S5, according to the desired number of working air compressors, the number of spare air compressors is selected, including: If the desired number of air compressors is If the number is 1 to 3, select the number of spare air compressors 1 unit; If the desired number of air compressors is If there are 4 to 5 units, select the number of spare air compressors For 2 units; If the desired number of air compressors is If the number of air compressors is 6 or more, select the number of spare air compressors. For 3 units.

7. The method for selecting an air compressor for an air cushion surge chamber of a hydropower station as claimed in claim 1, characterized in that: In step S6, the number of air compressors finally selected is ,but An air compressor with the same model parameters can be used for both inflation and replenishment.

8. The method for selecting an air compressor for an air system of an air cushion surge chamber of a hydropower station according to any one of claims 1 to 7, characterized in that: In step S7, the selected air compressor rated exhaust pressure is 1.0 MPa to 2.0 MPa higher than the maximum air pressure in the air chamber during the hydraulic transition process of the water transmission and power generation system of the hydropower station.

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