Urban substation rainstorm flood prediction method based on small-range hydrological characteristic unit

Abstract

The application discloses a rainstorm flood forecasting method for urban transformer substations based on small-range hydrological characteristic units, which comprises the following steps: 1, setting a water depth sensor in the urban transformer substation where flood forecasting is needed, and the water depth sensor should be set at the lowest point of the field area in the transformer substation; 2, storing all actual water depth data detected by the water depth sensor at all times in a database; 3, according to the forecasted precipitation process of meteorological forecasting, the computer system running the rainstorm flood model is used to calculate the future forecasted flood calculation results of the area where the urban transformer substation is located, and the results are stored in the database; 4, when rainstorm occurs in the area where the urban transformer substation is located and the urban transformer substation is in the phenomenon of waterlogging, the measured water depth data are compared with the corresponding forecasted simulated flood calculation results, and the deviation rate is obtained; 5, correcting the forecasted flood calculation results. The application can solve the distortion caused by unpredictable disturbance when the rainstorm flood is forecasted in the urban transformer substation.

Description

Technical Field

[0001] This invention relates to the field of flood early warning technology for urban substations, and in particular to a method for predicting rainstorm floods in urban substations based on small-scale hydrological characteristic units. Background Technology

[0002] In recent years, extreme weather events have occurred in many parts of the world, with heavy and torrential rains in many areas, damaging substations in several cities. The flood early warning capability of substations has become extremely important. Utilizing sophisticated rainstorm and flood models to forecast flood conditions at substations enables rapid forecasting and assessment of flood disasters, buying valuable time for flood prevention and emergency management at substations.

[0003] In large-scale flood modeling at the urban level, due to the large watershed area and significant water storage capacity, the predicted flood results, such as water depth, water level, and flow rate, will not differ significantly from the actual flood data in cases of abnormal conditions, such as blockages in stormwater pipe networks, clogged storm drains, or debris blocking drainage channels. The predicted results are often acceptable.

[0004] When forecasting floods in small-scale hydrological units such as substations, it is necessary to delineate the hydrological units based on the surrounding topography and geomorphology, and these units are often not very large.

[0005] However, due to the lack of regulation and storage capacity of a large watershed, the simulated flood forecasts will deviate significantly from the actual water depth, water level, flow rate, and other data when abnormal operating conditions or unforeseen accidents occur, resulting in a large discrepancy between the forecasts and the actual situation.

[0006] Furthermore, because the rainstorm and flood model is a time series model, meaning that the output data of the previous period is used as the input data of the next period, the simulation results will have accumulated errors, and the forecast results of all subsequent periods will be biased, and the bias may even increase with each period.

[0007] Therefore, how to solve the distortion caused by unforeseen disturbances in the prediction of rainstorms and floods in small hydrological units such as urban substations has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of the above-mentioned deficiencies of the prior art, the present invention provides a method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units. The purpose of this method is to solve the distortion caused by unpredictable disturbances when making rainstorm and flood predictions using small-scale hydrological characteristic units such as urban substations as the research object.

[0009] To achieve the above objectives, this invention discloses a method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units, comprising the following steps:

[0010] Step 1: Install water depth sensors within the urban substation area where flood forecasting is required. The water depth sensors should be installed at the lowest point of the substation area.

[0011] Step 2: The water depth sensor stores the actual water depth data h at all detected moments in the database;

[0012] Step 3: Based on the forecasted precipitation process, the computer system running the rainstorm and flood model calculates the future forecasted flood results h for the area where the urban substation is located. m And store it in the database;

[0013] Step 4: When a rainstorm occurs in the area where the urban substation is located, and the urban substation experiences flooding, the computer system will compare the measured water depth data h with the corresponding flood forecast simulation calculation result h. m Compare the results and obtain the deviation rate η;

[0014] Step 5: When the deviation rate η is greater than the deviation rate threshold, the flood forecast calculation result is corrected, as follows:

[0015] Step 5.1: Model the urban substation and divide it into several meshes using the finite element method;

[0016] Step 5.2: Set up a virtual sluice gate at the main outlet section of each grid, and set a virtual opening degree φ for the nth virtual sluice gate. n n is a natural number greater than or equal to 1;

[0017] Step 5.3: Calculate the virtual opening degree φ for each of the above steps. n The virtual opening degree φ of each virtual sluice gate is given. n Assignment;

[0018] Step 5.4: Based on each of the aforementioned virtual opening degrees φ n Calculate the corrected simulated water depth h' for the i-th time period. m,i ;

[0019] Step 5.5: Calculate the corrected simulated water depth h' for all subsequent time periods in sequence. m,i+1 h' m,i+2 h' m,i+3 The calculation results are stored in the database and displayed in the modeling of the urban substation.

[0020] Preferably, in step 3, the computer system running the rainstorm and flood model calculates the forecast flood results for the area where the urban substation is located for the next 24 to 72 hours each time based on the forecast precipitation process.

[0021] Preferably, in step 5.1, the urban substation is divided into finite element methods based on hydrological characteristics, and each grid includes at least one hydrological characteristic.

[0022] Preferably, the deviation rate threshold is 20%.

[0023] Preferably, in step 4, the formula for calculating the deviation rate η is as follows:

[0024]

[0025] Preferably, the rainstorm and flood model follows the principle of water balance, and the specific formula is as follows:

[0026]

[0027] Among them, P i-1 and P i , i and ii, represent the rainfall intensity for the (i-1)th and ith time periods, respectively, in mm / s; F represents the area of ​​the hydrological characteristic unit, in km². 2 Q ini-1 and Q ini These are the surface inflow volumes for the (i-1)th and ith time periods, respectively, in m³. 3 / s;Q outi-1 and Q outi These represent the outflow volumes for the (i-1)th and ith time periods, respectively, in m³. 3 / s; Z represents the evaporation intensity within the hydrological characteristic unit, in mm / s; q represents the water consumption within the hydrological characteristic unit, in m³ / s. 3 / s,f i-1 and f i These represent the water accumulation areas for the (i-1)th and ith time periods, respectively, in km². 2 .

[0028] More preferably, each of the aforementioned virtual opening degrees φ n The calculation formula is as follows:

[0029]

[0030] in, The average virtual opening degree is calculated using the following formula:

[0031]

[0032] e is the natural constant;

[0033] ω is an adjustment factor, ranging from 0.7 to 1.3.

[0034] More preferably, the simulated water depth h' of the hydrological feature unit corresponding to the nth virtual sluice gate in the i-th time period is corrected. m,i The calculation formula is as follows:

[0035]

[0036] The beneficial effects of this invention are:

[0037] This invention can solve the distortion caused by unforeseen disturbances when making rainstorm and flood predictions in small-scale hydrological characteristic units such as urban substations.

[0038] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0039] Figure 1 A flowchart of an embodiment of the present invention is shown.

[0040] Figure 2 This diagram illustrates a gridded underlying surface of an urban substation according to an embodiment of the present invention. Detailed Implementation

[0041] Example

[0042] like Figure 1 and Figure 2 As shown, the method for predicting rainstorms and floods at urban substations based on small-scale hydrological characteristic units includes the following steps:

[0043] Step 1: Install water depth sensors within the urban substation area where flood forecasting is required. The water depth sensors should be installed at the lowest point of the substation area.

[0044] Step 2: The depth sensor stores the actual water depth data h at all detected moments in the database;

[0045] Step 3: Based on the forecasted precipitation process, the computer system running the rainstorm and flood model calculates the future forecasted flood results h for the area where the urban substation is located. m And store it in the database;

[0046] Step 4: When a rainstorm occurs in the area where the urban substation is located, and the urban substation experiences flooding, the computer system will compare the measured water depth data h with the corresponding flood forecast simulation calculation result h. m Compare the results and obtain the deviation rate η;

[0047] Step 5: When the deviation rate η is greater than the deviation rate threshold, the flood forecast calculation results are corrected as follows:

[0048] Step 5.1: Model the urban substation and divide it into several meshes using the finite element method;

[0049] Step 5.2: Set up virtual sluice gates at the main outlet sections of each grid, and set a virtual opening degree φ for the nth virtual sluice gate. n n is a natural number greater than or equal to 1;

[0050] Step 5.3: Calculate each virtual opening degree φ n Give each virtual sluice gate a virtual opening / closing degree φ n Assignment;

[0051] Step 5.4: Based on each virtual opening degree φ n Calculate the corrected simulated water depth h' for the i-th time period. m,i ;

[0052] Step 5.5: Calculate the corrected simulated water depth h' for all subsequent time periods in sequence. m,i+1 h' m,i+2 h' m,i+3 The calculation results are stored in a database and displayed in the modeling of the urban substation. This invention introduces a virtual sluice gate module, which relies on real-time measured water depth data collected by a water depth sensor. When the deviation between the simulated water depth data and the measured water depth data exceeds a set threshold, the measured water depth data is substituted into the model to calculate a virtual opening and closing degree of the virtual sluice gate. In the model calculation of subsequent time periods, a virtual sluice gate is set at the key outlet section, and the virtual opening and closing degree is substituted as the virtual parameter of the virtual sluice gate.

[0053] In practical applications, the water flow at the outlet section at the end of each time period is affected by the virtual sluice gate, and the virtual opening and closing degree needs to be considered. However, the outflow at the beginning of the time period does not take into account the influence of the virtual sluice gate.

[0054] The virtual opening and closing degree of the virtual sluice gate can be greater than zero and less than 100%, indicating that there are unforeseen circumstances in the outflow channel within the simulated hydrological characteristic unit, such as blockage at the outlet or in the drainage pipe or canal, or other abnormal operating conditions. When the virtual opening and closing degree is 100%, it indicates that the outflow channel is in normal operating condition. The virtual opening and closing degree can also be greater than 100%, indicating that there are unforeseen pumping behaviors within the simulated hydrological characteristic unit.

[0055] In an urban context, floodwaters encounter numerous water-blocking channels during their journey, often consisting of buildings and bridge approach bridges.

[0056] Moreover, after floodwaters overflow river channels or bodies of water, their routes often run through urban roads, where unpredictable blockages can occur due to various obstructions.

[0057] In this scenario, a virtual sluice gate is set up at the main outflow section, and the calculation logic is consistent with the water depth simulation described above. It is important to note that using this method, the average confluence time of the studied hydrological characteristic units is... The time interval should be greater than the time interval calculated by the model (the time interval for urban rainstorm and flood models is generally chosen to be 0.5 or 1 hour) to achieve a better correction effect. This applies when the average runoff time of the hydrological characteristic unit is... When the computational response time of the model system is less than that of the model system, it becomes meaningless to use a virtual sluice gate to correct for unforeseen situations in the calculation of urban rainstorm and flooding models.

[0058] When the average confluence time of hydrological characteristic units When the time interval is less than the time interval calculated by the model, but greater than the calculation response time of the model system, the correction effect of the virtual sluice gate depends on the specific situation.

[0059] Therefore, when delineating hydrological characteristic units, it is necessary to pay attention to the average confluence time of the hydrological characteristic units under study. The calculation time interval should be greater than that of the urban rainstorm and flood model.

[0060] In some embodiments, in step 3, the computer system running the rainstorm and flood model calculates the forecast flood results for the area where the urban substation is located for the next 24 to 72 hours each time based on the forecast precipitation process.

[0061] In some embodiments, in step 5.1, the urban substation is divided into finite element units based on hydrological characteristics, and each hydrological characteristic unit includes at least one hydrological characteristic.

[0062] In practical applications, each virtual sluice gate must be set at the main outlet section of the corresponding hydrological characteristic unit, and only one virtual sluice gate can be set for each hydrological characteristic unit, not multiple ones.

[0063] In some embodiments, the deviation rate threshold is 20%.

[0064] In some embodiments, the formula for calculating the deviation rate η in step 4 is as follows:

[0065]

[0066] In some embodiments, the rainstorm flood model follows the water balance principle, with the specific formula as follows:

[0067]

[0068] Among them, Pi-1 and P i , i and ii, represent the rainfall intensity for the (i-1)th and ith time periods, respectively, in mm / s; F represents the area of ​​the hydrological characteristic unit, in km². 2 Q ini-1 and Q ini These are the surface inflow volumes for the (i-1)th and ith time periods, respectively, in m³. 3 / s;Q outi-1 and Q outi These represent the outflow volumes for the (i-1)th and ith time periods, respectively, in m³. 3 / s; Z represents the evaporation intensity within the hydrological characteristic unit, in mm / s; q represents the water consumption within the hydrological characteristic unit, in m³ / s. 3 / s,f i-1 and f i These represent the water accumulation areas for the (i-1)th and ith time periods, respectively, in km². 2 .

[0069] In some embodiments, each virtual opening degree φ n The calculation formula is as follows:

[0070]

[0071] in, The average virtual opening degree is calculated using the following formula:

[0072]

[0073] e is the natural constant;

[0074] ω is an adjustment factor, ranging from 0.7 to 1.3.

[0075] In practical applications, urban substations are divided into several hydrological characteristic units using the finite element method. The overall system of equations conforms to the water conservation formula and the momentum conservation formula. In this case, the virtual opening and closing degree calculated using a virtual sluice gate represents the average virtual opening and closing degree of the hydrological characteristic units.

[0076] A virtual sluice gate is set up in each hydrological characteristic unit. The adjustment coefficient ω needs to be determined based on the underlying surface conditions and gradient of each hydrological characteristic unit, that is, the ratio of the highest point of the corresponding hydrological characteristic unit minus the outlet elevation to the length of the water flow path.

[0077] The adjustment coefficient ω is related to the underlying surface conditions and gradient of the corresponding hydrological characteristic unit. The larger the gradient of the nth hydrological characteristic unit, the larger the value of the adjustment coefficient ω. The larger the roughness of the nth hydrological characteristic unit, which reflects the influence of boundary surface roughness on water flow resistance, the smaller the value of the adjustment coefficient ω.

[0078] When there is relatively abundant observational data on local meteorological station precipitation and flooding processes, the adjustment coefficient ω of each grid within the hydrological characteristic unit can be calibrated using historical flooding processes.

[0079] In some embodiments, the simulated water depth h' of the hydrological feature unit corresponding to the nth virtual sluice gate is adjusted for the i-th time period. m,i The calculation formula is as follows:

[0080]

[0081] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for predicting rainstorms and floods at urban substations based on small-scale hydrological characteristic units; characterized in that, Includes the following steps: Step 1: Install water depth sensors within the urban substation area where flood forecasting is required. The water depth sensors should be installed at the lowest point of the substation area. Step 2: The water depth sensor will detect the actual water depth data at all times. Stored in a database; Step 3: Based on the forecasted precipitation process, the computer system running the rainstorm and flood model calculates the future forecasted flooding results for the area where the urban substation is located. And store it in the database; The rainstorm and flood model follows the principle of water balance, and the specific formula is as follows: ； in, and The first -1 and the first Rainfall intensity for each time period, in mm / s; The area of ​​the hydrological characteristic unit is expressed in km². 2 ; and The first -1 and the first Surface inflow rate for each time period, in m³ / s. 3 / s; and The first -1 and the first Outflow rate for each time period, in m³ / s 3 / s; Evaporation intensity within a hydrological characteristic unit, in mm / s; Water consumption within a hydrological characteristic unit, in m³. 3 / s, and The first -1 and the first The area of ​​water accumulation during each time period, in km². 2 ; Each of the aforementioned virtual opening degrees The calculation formula is as follows: ； in, The average virtual opening degree; Step 4: When a rainstorm occurs in the area where the urban substation is located, and the urban substation experiences flooding, the computer system will transmit the measured water depth data. The corresponding flood forecast simulation calculation results Compare the results and obtain the deviation rate. ; Step 5, when the deviation rate When the deviation rate exceeds the threshold, the flood forecast calculation results are corrected as follows: Step 5.1: Model the urban substation and divide it into several meshes using the finite element method; Step 5.2: Set up a virtual sluice gate at the main outlet section of each grid, and for the first... Each of the aforementioned virtual sluice gates is configured with a virtual opening / closing degree. ; It is a natural number greater than or equal to 1; Step 5.3: Calculate the virtual opening degree for each of the above steps. The virtual opening / closing degree of each of the virtual sluice gates. Assignment; Step 5.4: Based on each of the aforementioned virtual opening / closing degrees Determine the subsequent steps The simulated water depth after correction for each time period ; Step 5.5: Calculate all the corrected simulated water depths for subsequent time periods in sequence. , , The calculation results are stored in the database and displayed in the modeling of the urban substation.

2. The method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units according to claim 1, characterized in that, In step 3, the computer system running the rainstorm and flood model calculates the forecast flood results for the area where the urban substation is located for the next 24 to 72 hours each time based on the forecast precipitation process.

3. The method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units according to claim 1, characterized in that, In step 5.1, the urban substation is divided into grids using finite element methods based on hydrological characteristics, and each grid includes at least one hydrological characteristic.

4. The method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units according to claim 1, characterized in that, The deviation rate threshold is 20%.

5. The method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units according to claim 1, characterized in that, In step 4, the deviation rate The calculation formula is as follows: 。 6. The method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units according to claim 1, characterized in that, Average virtual opening degree The calculation formula is as follows: ； It is a natural constant; The adjustment factor is between 0.7 and 1.

3.

7. The method for predicting rainstorms and floods in urban substations based on small-scale hydrological characteristic units according to claim 6, characterized in that, No. The hydrological feature units corresponding to the virtual sluice gates in the first... The simulated water depth after correction for each time period The calculation formula is as follows: 。

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