Hydropower station operation corridor radon concentration-fan frequency conversion linkage prevention and control method

Abstract

The invention discloses a hydropower station operation corridor radon gas concentration-fan frequency conversion linkage prevention and control method. The method comprises the following steps that S1, ventilation systems are evenly distributed in all ventilation branches of a corridor; s2, establishing an air volume database of the ventilator of each ventilation branch running at different frequencies; s3, acquiring data in real time, and predicting the data; s4, the upper computer monitoring platform sets the priority according to the real-time detection data and the predicted value of each ventilation branch, and determines the number of started ventilators and the starting sequence of the ventilators of each ventilation branch; and S5, controlling the ventilation system of each ventilation branch according to the priority. Radon discharge information in the corridor can be detected, the radon emission amount in the next time period can be predicted, and the operation frequency of a ventilator required by radon dilution can be dynamically adjusted in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilation of hydropower stations, and in particular to a linkage prevention and control method of radon gas concentration and fan frequency conversion in an operating gallery of a hydropower station. Background Art

[0002] Radon is a naturally occurring radioactive gas primarily derived from the decay of uranium and thorium in soil and rock. In the confined spaces of hydropower station operating corridors, particularly in bedrock caverns with poor ventilation in underground powerhouses, radon can easily accumulate. Excessive radon levels pose a health threat to workers and can lead to various diseases, including lung cancer, myeloid leukemia, stomach cancer, and skin cancer. To protect the health of workers, online monitoring of radon levels in underground corridors is necessary, along with the implementation of necessary ventilation measures to reduce radon levels. Traditional radon monitoring and control systems rely on static monitoring, adjusting airflow to increase airflow in specific areas by modifying ventilation facilities. However, this approach has a relatively long adjustment cycle. Furthermore, because radon outflow rates vary across different dam sections and water levels in the corridor, variable frequency control of the fans cannot be tailored to radon concentrations. This, in turn, requires intelligent variable frequency control of the mine ventilation fan branches to adjust airflow through the ventilation network system and the mine ventilation monitoring system. Summary of the Invention

[0003] The present invention aims to solve the technical problems existing in the prior art. In particular, it innovatively proposes a linkage prevention and control method of radon gas concentration and fan frequency conversion in the operating corridor of a hydropower station. The method can detect radon exhaust information in the corridor, predict the radon gas outflow in the next period, and dynamically adjust the operating frequency of the fan required to dilute the radon gas in real time.

[0004] To achieve the above objectives, the present invention provides a method for controlling radon gas concentration in a hydropower station operation gallery and fan frequency conversion, comprising the following steps:

[0005] S1: A ventilation system is arranged in each ventilation branch of the corridor, the ventilation system includes a plurality of ventilators arranged at intervals along the extension direction of the corridor, the ventilators are equipped with a frequency converter, a radon gas detection point is arranged at each ventilator and at the midpoint of two adjacent ventilators, each radon gas detection point is provided with a radon gas detection sensor, and an air volume sensor is provided at the entrance and exit of each ventilation branch;

[0006] The ventilation system is further provided with a PLC control substation and a signal transceiver in the ventilation branch, the ventilator drive signal input end is connected to the ventilation drive signal output end of the PLC control substation, the frequency converter frequency conversion signal input end is connected to the frequency conversion signal output end of the PLC control substation, the detection output end of the radon gas detection sensor in the same corridor is connected to the detection signal input end of the signal transceiver of the corridor, and the detection signal output end of the signal transceiver is connected to the detection signal input end of the PLC control substation of the corridor;

[0007] It also includes a PLC control main station. The signal output terminals of the PLC control substations of each ventilation branch are connected to the signal input terminals of the PLC control main station. The signal output terminals of the PLC control main station are connected to the signal input terminals of the upper computer monitoring platform.

[0008] S2: Establish a database of air volume of each ventilation branch fan operating at different frequencies;

[0009] S3: Acquire data in real time and make predictions on the data;

[0010] S4: The upper computer monitoring platform sets the priority according to the real-time detection data and predicted value of each ventilation branch, and determines the number and startup sequence of the fans in each ventilation branch;

[0011] S5: Control the ventilation system of each ventilation branch according to priority.

[0012] In the above scheme, step S2 includes the following contents:

[0013] S2-1: Set the initial normal air volume Q0, radon concentration C0 and radon concentration safety threshold C of each ventilation branch according to the length, temperature and safety factor of each ventilation branch. a , and calculate the radon gas emission threshold of each corridor;

[0014] Calculated by the following formula:

[0015] w0=Q0C a

[0016] Where w0 is the radon gas outburst threshold;

[0017] S2-2: Randomly select one ventilator from each ventilation branch for fitting;

[0018] S2-3: The PLC control substation sends a frequency signal to the frequency converter of the ventilator to adjust the frequency of the ventilator, and the air volume sensor detects the air volume data of the ventilator at different frequencies;

[0019] S2-4: Establish the functional relationship between air volume and fan operating frequency as follows:

[0020] Qn =kf n +m

[0021] Among them, n represents different corridors, Q n is the ventilation volume of the nth corridor, f n is the frequency of the fan in the nth corridor, k is the coefficient, and m is a constant.

[0022] In the above scheme, step S3 includes the following contents:

[0023] S3-1: Radon gas concentration C at different locations of ventilation branches is collected in real time through radon gas detection sensors and air volume sensors. i and air volume Q i The signal is sent to the PLC control substation through the signal transceiver. The PLC control substation calculates the real-time average radon gas concentration and real-time average air volume of the ventilation branch, and calculates the average value of the radon gas outflow in the current period by the following formula:

[0024] w i ′=Q i 'C i '

[0025] Where w′ i is the average radon gas outflow in the current period, Q′ i is the average wind volume in the current period, C′ i is the average value of radon concentration in the current period;

[0026] S3-2: Based on the average value w′ of radon gas outflow in the current period i and the average value of radon gas outflow in the previous period w i-1 ′, predict the average value of radon gas outflow in the next period w i+1 ';

[0027] Calculated using the following formula:

[0028] w i+1 ′=w i ′+α

[0029] Where α is the adjustment coefficient, which is dynamically corrected according to environmental parameters;

[0030] S3-3: Predict the average radon concentration in the next period of time, calculated using the following formula:

[0031]

[0032] Where w i+1 ' is the average value of radon gas outflow in the next period, Q' i is the average wind volume in the current period, C i+1′ is the average radon concentration in the next period.

[0033] In the above solution: step S4 also includes:

[0034] If the average radon concentration C' detected in real time by the ventilation branch i Or the predicted average radon concentration C for the next period i+1 ′ is greater than the radon concentration safety threshold C a If the ventilation branch priority is 120%, the ventilation branch priority is set to level 1, and the ventilator of this ventilation branch is started or adjusted first;

[0035] If the average radon concentration of a ventilation branch is greater than 80% of the safety threshold and less than 120% of the safety threshold, the priority of the ventilation branch is set to level 2. After all ventilation branches with a priority of level 1 are started or adjusted, the ventilator of this ventilation branch is started or adjusted.

[0036] If the average radon gas concentration of the ventilation branch is less than 80% of the set safety threshold, the priority of the ventilation branch is set to level 3. After all ventilation branches with priorities 1 and 2 are started or adjusted, the ventilator of the ventilation branch is started or adjusted and operates normally.

[0037] Repeat this step until all ventilation branches have their priorities set.

[0038] In the above scheme, step S5 includes the following contents:

[0039] S5-1: Start the ventilation system of the ventilation branch with priority level 1;

[0040] S5-1-1: Execute steps S5-1-2 and S5-1-3 simultaneously;

[0041] S5-1-2: Immediately start all fans of the ventilation branch;

[0042] S5-1-2-1: Calculate the operating frequency of each fan in the ventilation branch;

[0043] S5-1-2-2: The average value w of the radon gas outflow in the next period predicted in step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 ';

[0044] Calculated using the following formula:

[0045]

[0046] Where Q i+1' is the average air volume required for the next period of the ventilation branch;

[0047] S5-1-2-3: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-1-2-5;

[0048] S5-1-2-4: Predict the operating frequency f of the ventilator in the ventilation branch by using the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator established in step S2-4. i+1 ;

[0049] If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan, the PLC control substation sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan to n Hz;

[0050] Execute S5-1-3;

[0051] S5-1-2-5: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-1-2-4; otherwise, run according to the current frequency;

[0052] S5-1-3: Start some of the fans in the adjacent ventilation branch that are close to the ventilation branch; the number of these fans is half of the number of fans in the adjacent ventilation branch;

[0053] S5-2: Start the ventilation system of the ventilation branch with priority level 2;

[0054] S5-3: Start the ventilation system of the ventilation branch with priority level 3.

[0055] In the above solution, step S5-2 includes:

[0056] S5-2-1: Determine the start-up sequence of the ventilators; obtain the radon gas concentration at different locations of the ventilation branch through the radon gas detection sensor and send it to the PLC control substation. The PLC control substation will prioritize driving the ventilator at the location with the highest concentration, and then start the remaining ventilators on both sides of the nearest ventilator in sequence. The start-up interval between adjacent fans should be ≥ 10 seconds, and the air volume and radon gas concentration values ​​of the adjacent ventilation branches should be dynamically monitored;

[0057] S5-2-2: Determine the operating frequency of each ventilator and drive each ventilator according to the starting sequence;

[0058] The average value w of the radon gas outflow in the next period predicted in step S3-2 i+1 ′ and the set radon concentration safety threshold C a, predict the average air volume Q required for the ventilation branch in the next period i+1 ';

[0059] Calculated using the following formula:

[0060]

[0061] Where Q i+1 ' is the average air volume required for the next period of the ventilation branch;

[0062] S5-2-2-1: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-2-2-3;

[0063] S5-2-2-2: Predict the operating frequency f of the ventilator in the ventilation branch by using the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator established in step S2-4. i+1 ;

[0064] If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan, the PLC control substation sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan to n Hz;

[0065] S5-2-2-3: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, execute S5-2-2-2; otherwise, run according to the current frequency.

[0066] In the above scheme, step S5-3 includes:

[0067] S5-3-1: Determine the number and order of activating the fans in the ventilation branch; maintain operation at the lowest total power, shut down redundant fans in the ventilation branch, and prioritize activating the fan with the shortest operating time among all fans in the ventilation branch. If the operating times are the same, rotate them in order of fan number.

[0068] S5-3-2: Determine the power sequence of the activated fans of the ventilation branch;

[0069] S5-3-2-1: The average value w of the radon gas outflow in the next period predicted according to step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 ';

[0070] Calculated using the following formula:

[0071]

[0072] Where Q i+1 ' is the average air volume required for the next period of the ventilation branch;

[0073] S5-3-2-2: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-3-2-4;

[0074] S5-3-2-3: Predict the operating frequency f of the ventilator in the ventilation branch by using the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator established in step S2-4. i+1 ;

[0075] If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan, the PLC control substation sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan to n Hz;

[0076] S5-3-2-4: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-3-2-3; otherwise, run according to the current frequency;

[0077] S5-3-3: Obtain the radon gas concentration of the ventilation branch in real time through the PLC control substation, calculate the average value of the radon gas concentration of the ventilation branch, and send the average value of the radon gas concentration to the PLC control main station. If the average value of the radon gas concentration does not change, repeat this step; if the average value of the radon gas concentration changes, execute S3.

[0078] In the above solution: the spacing between the ventilators is 140m, and the ventilators are all fixed on the ground of the ventilation branch.

[0079] In the above scheme, two radon gas detection sensors are installed at each radon gas detection point, and the two radon gas detection sensors are installed vertically and spaced apart on the inner wall of the ventilation branch. Due to the mechanical ventilation near the ventilator 2 in the corridor, the airflow is relatively turbulent. To avoid inaccurate radon gas concentration detection, two radon gas detection sensors are specially installed.

[0080] In the above scheme: the host computer monitoring platform is equipped with a priority scheduling module, the host computer monitoring platform and the PLC control station communicate using industrial Ethernet, and the PLC control substations of each corridor communicate with the PLC control station using RS485 bus.

[0081] In summary, the beneficial effects of the present invention are as follows: according to the ventilation environment monitoring requirements of the hydropower station corridor, radon gas detection sensors and air volume sensors are installed in the corridors, ventilation passages and other areas where people are present in the hydropower station to monitor the radon gas concentration and air volume in the hydropower station, and a layout method for sensors, ventilators, PLC control cabinets and signal transceiver devices in the corridor is provided. The number of fans to be started and the order of starting are determined according to the current environmental parameters, and the air volume-frequency servo control method is used to predict the air volume required to dilute the radon gas concentration to the safety threshold, and the ventilator frequency is dynamically adjusted in real time according to the air volume requirements. The radon exhaust environment information in the ventilation branch is detected by multiple radon gas sensors, and the radon gas outflow volume and air volume parameters of a certain branch in the current period are used to iteratively calculate and predict the radon gas outflow volume in the next period, and then calculate the air volume required to dilute the current radon gas volume to the safety threshold, and determine the corresponding frequency through the established air volume-frequency function relationship of each ventilation branch. This technical solution couples the ventilation branch with the fan frequency control. While monitoring the radon concentration, it dynamically adjusts the operating frequency of the fan required to dilute the radon gas in real time, realizing radon monitoring-fan frequency conversion servo closed-loop control. The frequency is intelligently adjusted according to the air volume demand, with fast adjustment speed and reduced energy consumption. At the same time, multi-fan joint control and priority scheduling function modules are added. According to the judgment conditions and priority rules for starting the fan, multi-fan integrated control is realized to ensure the stability and reliability of the ventilation system and improve the overall prevention and control effect and resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 Schematic diagram of the relationship between the air volume and frequency function of the ventilation branch of the present invention;

[0083] Figure 2 Schematic diagram of the installation position of the ventilation system of the present invention;

[0084] Figure 3 This is a schematic cross-sectional view of the installation position of the ventilation system of the present invention;

[0085] Figure 4 is a network structure diagram of each ventilation system of the present invention;

[0086] Figure 5 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0087] The present invention will be further described below by way of examples and in conjunction with the accompanying drawings:

[0088] like Figures 1 to 5 As shown, a method for controlling radon gas concentration in a hydropower station operation corridor and fan frequency conversion in a linked manner includes the following steps:

[0089] S1: A ventilation system is arranged in each ventilation branch of the corridor, and the ventilation system includes a plurality of ventilators 2 arranged at intervals along the extension direction of the corridor. The ventilators 2 of this embodiment are spaced 140m apart. The ventilators 2 are all equipped with frequency converters and fixed on the ground of the ventilation branches. A radon gas detection point is provided at each ventilator 2 and at the midpoint of two adjacent ventilators 2. Two radon gas detection sensors 6 are provided at each radon gas detection point. The two radon gas detection sensors 6 are vertically spaced apart and installed on the inner wall of the ventilation branch. An air volume sensor 5 is provided at the entrance and exit of the ventilation branch.

[0090] The ventilation system is further provided with a PLC control substation 4 and a signal transceiver 7 in the ventilation branch, the drive signal input end of the ventilator 2 is connected to the ventilation drive signal output end of the PLC control substation 4, the frequency converter frequency conversion signal input end is connected to the frequency conversion signal output end of the PLC control substation 4, the detection output end of the radon gas detection sensor 6 in the same corridor is connected to the detection signal input end of the signal transceiver 7 of the corridor, and the detection signal output end of the signal transceiver 7 is connected to the detection signal input end of the PLC control substation 4 of the corridor;

[0091] It also includes a PLC control main station. The signal output terminals of the PLC control substations 4 of each ventilation branch are connected to the signal input terminals of the PLC control main station. The signal output terminals of the PLC control main station are connected to the signal input terminals of the host computer monitoring platform. The host computer monitoring platform and the PLC control main station communicate using industrial Ethernet. The PLC control substations 4 of each corridor communicate with the PLC control main station using RS485 bus.

[0092] S2: Establish the air volume database of the fan 2 of each ventilation branch running at different frequencies, and draw a functional relationship diagram, such as Figure 1 As shown;

[0093] S2-1: Set the initial normal air volume Q0, radon concentration C0 and radon concentration safety threshold C of each ventilation branch according to the length, temperature and safety factor of each ventilation branch. a , and calculate the radon gas emission threshold of each corridor;

[0094] Calculated by the following formula:

[0095] w0=Q0C a

[0096] Where w0 is the radon gas outburst threshold;

[0097] S2-2: Randomly select one ventilator 2 from each ventilation branch for fitting;

[0098] S2-3: Sending a frequency signal to the frequency converter of the ventilator 2 via the PLC control substation 4 to adjust the frequency of the ventilator 2, and detecting the air volume data of the ventilator 2 at different frequencies via the air volume sensor 5;

[0099] S2-4: Establish the functional relationship between air volume and operating frequency of fan 2 as follows:

[0100] Q n =kf n +m

[0101] Where n represents different corridors, n = 1, 2, 3, ..., Q n is the ventilation volume of the nth corridor, f n is the frequency of fan 2 in the nth corridor, k is the coefficient, and m is a constant;

[0102] S3: Acquire data in real time and make predictions on the data;

[0103] S3-1: The radon gas concentration C at different locations of the ventilation branch is collected in real time through the radon gas detection sensor 6 and the air volume sensor 5. i and air volume Q i , and sent to the PLC control substation 4 through the signal transceiver 7. The PLC control substation 4 calculates the real-time average radon concentration and real-time average air volume of the ventilation branch, and calculates the average value of the radon outflow in the current period by the following formula:

[0104] w i ′=Q i 'C i '

[0105] Where w′ i is the average radon gas outflow in the current period, Q′ i is the average wind volume in the current period, C′ i is the average value of radon concentration in the current period;

[0106] S3-2: Based on the average value w′ of radon gas outflow in the current period i and the average value of radon gas outflow in the previous period w i-1 ′, predict the average value of radon gas outflow in the next period w i+1 ';

[0107] Calculated using the following formula:

[0108] w i+1 ′=w i ′+αw i ′-w i-1 '

[0109] Where α is the adjustment coefficient, which is dynamically corrected according to environmental parameters;

[0110] S3-3: Predict the average radon concentration in the next period of time, calculated using the following formula:

[0111]

[0112] Where w i+1 ' is the average value of radon gas outflow in the next period, Q' i is the average wind volume in the current period, C i+1 ' is the average radon concentration in the next period;

[0113] S4: The priority scheduling module of the upper computer monitoring platform sets the priority according to the real-time detection data and predicted value of each ventilation branch, and determines the number of fans to be started and the starting order of each ventilation branch;

[0114] If the average radon concentration C' detected in real time by the ventilation branch i Or the predicted average radon concentration C for the next period i+1 ′ is greater than the radon concentration safety threshold C a If the ventilation branch priority is 120%, the ventilation branch priority is set to level 1, and the fan 2 of the ventilation branch is started or adjusted first;

[0115] If the average radon concentration of the ventilation branch is greater than 80% of the safety threshold and less than 120% of the safety threshold, the priority of the ventilation branch is set to level 2. After all ventilation branches with a priority of level 1 are started or adjusted, the fan 2 of the ventilation branch is started or adjusted.

[0116] If the average radon gas concentration of the ventilation branch is less than 80% of the set safety threshold, the priority of the ventilation branch is set to level 3. After all ventilation branches with priorities 1 and 2 are started or adjusted, the ventilator 2 of the ventilation branch is started or adjusted to operate normally.

[0117] Repeat this step until all ventilation branches have their priorities set;

[0118] S5: Control the ventilation system of each ventilation branch according to priority;

[0119] S5-1: Start the ventilation system of the ventilation branch with priority level 1;

[0120] S5-1-1: Execute steps S5-1-2 and S5-1-3 simultaneously;

[0121] S5-1-2: Immediately start all fans 2 of the ventilation branch;

[0122] S5-1-2-1: Calculate the operating frequency of each fan 2 of the ventilation branch;

[0123] S5-1-2-2: The average value w of the radon gas outflow in the next period predicted in step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 ';

[0124] Calculated using the following formula:

[0125]

[0126] Where Q i+1 ' is the average air volume required for the next period of the ventilation branch;

[0127] S5-1-2-3: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-1-2-5;

[0128] S5-1-2-4: Predict the operating frequency f of the ventilator in the ventilation branch by using the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator 2 established in step S2-4. i+1 ;

[0129] If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan 2, the PLC control substation 4 sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan 2 to n Hz;

[0130] Execute S5-1-3;

[0131] S5-1-2-5: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-1-2-4; otherwise, run according to the current frequency;

[0132] S5-1-3: Start some fans 2 in adjacent ventilation branches that are close to the adjacent ventilation branches; the adjacent ventilation branches include ventilation branches connected to the adjacent ventilation branches and adjacent ventilation branches, and the number of some fans 2 is half the number of fans 2 in the adjacent ventilation branches;

[0133] The ventilator 2 of the adjacent ventilation branch adopts a soft start mode one by one;

[0134] The PLC control substation 4 of the adjacent ventilation branch starts at a distance from the average radon concentration exceeding the radon concentration safety threshold C. aThe nearest ventilator 2 of the ventilation branch, and start the remaining ventilators 2 on both sides of the nearest ventilator 2 in sequence, and the adjacent fan start interval is ≥ 10 seconds, and the air volume and radon concentration value of the adjacent ventilation branch are dynamically monitored;

[0135] S5-1-4: The PLC control substation 4 obtains the radon gas concentration detected by all radon gas detection sensors 6 of the ventilation branch in real time, calculates the average radon gas concentration of the ventilation branch, and sends the average radon gas concentration to the PLC control main station. If the average radon gas concentration does not change, repeat this step; if the average radon gas concentration changes, execute S3;

[0136] S5-2: Start the ventilation system of the ventilation branch with priority level 2;

[0137] S5-2-1: Determine the startup sequence of the ventilators 2; obtain the radon gas concentration at different locations of the ventilation branch through the radon gas detection sensor 6 and send it to the PLC control substation 4. The PLC control substation 4 preferentially drives the ventilator 2 at the location with the highest concentration, and sequentially starts the remaining ventilators 2 on both sides of the nearest ventilator 2 in order, with the startup interval of adjacent fans being ≥10 seconds, and dynamically monitors the air volume and radon gas concentration values ​​of the adjacent ventilation branches;

[0138] S5-2-2: Determine the operating frequency of each ventilator 2 and drive each ventilator 2 according to the starting sequence;

[0139] The average value w of the radon gas outflow in the next period predicted in step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 ';

[0140] Calculated using the following formula:

[0141]

[0142] Where Q i+1 ' is the average air volume required for the next period of the ventilation branch;

[0143] S5-2-2-1: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-2-2-3;

[0144] S5-2-2-2: Predict the operating frequency f of the ventilator in the ventilation branch by using the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator 2 established in step S2-4. i+1 ;

[0145] If the predicted operating frequency f i+1When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan 2, the PLC control substation 4 sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan 2 to n Hz;

[0146] S5-2-2-3: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-2-2-2; otherwise, run according to the current frequency;

[0147] S5-3: Start the ventilation system of the ventilation branch with priority level 3;

[0148] S5-3-1: Determine the number and order of activating the ventilators 2 of the ventilation branch; maintain operation at the lowest total power, shut down the redundant ventilators 2 of the ventilation branch, and prioritize activating the ventilator 2 with the shortest operating time among all the ventilators 2 in the ventilation branch. If the operating times are the same, rotate the ventilators 2 in order of their serial numbers;

[0149] S5-3-2: Determine the power sequence of the activated fans 2 of the ventilation branch;

[0150] S5-3-2-1: The average value w of the radon gas outflow in the next period predicted according to step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 ';

[0151] Calculated using the following formula:

[0152]

[0153] Where Q i+1 ' is the average air volume required for the next period of the ventilation branch;

[0154] S5-3-2-2: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-3-2-4;

[0155] S5-3-2-3: Predict the operating frequency f of the ventilator in the ventilation branch by using the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator 2 established in step S2-4. i+1 ;

[0156] If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan 2, the PLC control substation 4 sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan 2 to n Hz;

[0157] S5-3-2-4: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-3-2-3; otherwise, run according to the current frequency;

[0158] S5-3-3: The radon gas concentration of the ventilation branch is obtained in real time through the PLC control substation 4, and the average value of the radon gas concentration of the ventilation branch is calculated, and the average value of the radon gas concentration is sent to the PLC control main station. If the average value of the radon gas concentration does not change, repeat this step; if the average value of the radon gas concentration changes, execute S3.

Claims

1. A method for controlling radon gas concentration in a hydropower station's operating gallery and fan frequency conversion, characterized by: The following steps are involved: S1: A ventilation system is arranged in each ventilation branch of the corridor, the ventilation system comprises a plurality of ventilators (2) arranged at intervals along the extension direction of the corridor, the ventilators (2) are all equipped with a frequency converter, a radon gas detection point is arranged at each ventilator (2) and at the midpoint of two adjacent ventilators (2), a radon gas detection sensor (6) is arranged at each radon gas detection point, and an air volume sensor (5) is arranged at the inlet and outlet of each ventilation branch; The ventilation system is further provided with a PLC control substation (4) and a signal transceiver (7) in the ventilation branch, wherein the drive signal input end of the ventilator (2) is connected to the ventilation drive signal output end of the PLC control substation (4), the frequency converter frequency conversion signal input end is connected to the frequency conversion signal output end of the PLC control substation (4), the detection output end of the radon gas detection sensor (6) in the same corridor is connected to the detection signal input end of the signal transceiver (7) in the corridor, and the detection signal output end of the signal transceiver (7) is connected to the detection signal input end of the PLC control substation (4) in the corridor; It also includes a PLC control main station, the signal output terminals of the PLC control substations (4) of each ventilation branch are connected to the signal input terminals of the PLC control main station, and the signal output terminals of the PLC control main station are connected to the signal input terminals of the host computer monitoring platform; S2: Establishing a database of air volume of fans (2) of each ventilation branch running at different frequencies; S3: Acquire data in real time and make predictions on the data; S4: The upper computer monitoring platform sets the priority according to the real-time detection data and predicted value of each ventilation branch, and determines the number and startup sequence of the fans in each ventilation branch; S5: Control the ventilation system of each ventilation branch according to priority.

2. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 1 is characterized by: Step S2 includes the following contents: S2-1: Set the initial normal air volume Q0, radon concentration C0 and radon concentration safety threshold C of each ventilation branch according to the length, temperature and safety factor of each ventilation branch. a , and calculate the radon gas emission threshold of each corridor; Calculated by the following formula: w0=Q0C a Where w0 is the radon gas outburst threshold; S2-2: Randomly select one ventilator (2) from each ventilation branch for fitting; S2-3: sending a frequency signal to the frequency converter of the ventilator (2) through the PLC control substation (4), adjusting the frequency of the ventilator (2), and detecting the air volume data of the ventilator (2) at different frequencies through the air volume sensor (5); S2-4: Establish the functional relationship between air volume and operating frequency of the ventilator (2) as follows: Q n =kf n +m Where n represents different corridors, n = 1, 2, 3, ..., Q n is the ventilation volume of the nth corridor, f n is the frequency of the fan (2) in the nth corridor, k is the coefficient, and m is a constant.

3. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 1 is characterized in that: Step S3 includes the following contents: S3-1: The radon gas concentration C at different locations of the ventilation branch is collected in real time through the radon gas detection sensor (6) and the air volume sensor (5). i and air volume Q i and sent to the PLC control substation (4) via the signal transceiver (7). The PLC control substation (4) calculates the real-time average radon concentration and the real-time average air volume of the ventilation branch, and calculates the average value of the radon outflow in the current period by the following formula: w i ′=Q i ′C i ′ Where w i ′ is the average value of radon gas outflow in the current period, Q i ′ is the average wind volume in the current period, C i ′ is the average radon concentration in the current period; S3-2: Based on the average value of radon gas outflow in the current period w i ′ and the average value of radon gas outflow in the previous period w i-1 ′, predict the average value of radon gas outflow in the next period w i+1 '; Calculated using the following formula: w i+1 ′=w i ′+α(w i ′-w i-1 ′) Where α is the adjustment coefficient, which is dynamically corrected according to environmental parameters; S3-3: Predict the average radon concentration in the next period of time, calculated using the following formula: Where w i+1 ′ is the average radon gas outflow in the next period, Q i ′ is the average wind volume in the current period, C i+1 ′ is the average radon concentration in the next period.

4. The method for controlling radon gas concentration in a hydropower station operation gallery and fan frequency conversion according to claim 1 is characterized in that: Step S4 further includes: If the average radon concentration C' detected in real time by the ventilation branch i Or the predicted average radon concentration C for the next period i+1 ′ is greater than the radon concentration safety threshold C a If the ventilation branch has a priority of 120%, the priority of the ventilation branch is set to level 1, and the fan of the ventilation branch is started or adjusted first (2); If the average radon gas concentration of the ventilation branch is greater than 80% of the safety threshold and less than 120% of the safety threshold, the priority of the ventilation branch is set to level 2, and after all ventilation branches with a priority of level 1 are started or adjusted, the ventilator of the ventilation branch is started or adjusted (2); If the average radon gas concentration of the ventilation branch is less than 80% of the set safety threshold, the priority of the ventilation branch is set to level 3. After all ventilation branches with priorities 1 and 2 are started or adjusted, the ventilator (2) of the ventilation branch is started or adjusted to operate normally. Repeat this step until all ventilation branches have their priorities set.

5. The method for controlling radon concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 1 is characterized in that: Step S5 includes the following contents: S5-1: Start the ventilation system of the ventilation branch with priority level 1; S5-1-1: Execute steps S5-1-2 and S5-1-3 simultaneously; S5-1-2: Immediately start all fans (2) of the ventilation branch; S5-1-2-1: Calculate the operating frequency of each ventilator (2) of the ventilation branch; S5-1-2-2: The average value w of the radon gas outflow in the next period predicted in step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 '; Calculated using the following formula: Where Q i+1 ' is the average air volume required for the next period of the ventilation branch; S5-1-2-3: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-1-2-5; S5-1-2-4: Based on the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator (2) established in step S2-4, the operating frequency f of the ventilator of the ventilation branch is predicted. i+1 ; If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan (2), the PLC control substation (4) sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan (2) to n Hz; Execute S5-1-3; S5-1-2-5: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-1-2-4; otherwise, run according to the current frequency; S5-1-3: starting some of the fans (2) in the adjacent ventilation branch that are close to the ventilation branch; the number of the some of the fans (2) is half the number of the fans (2) in the adjacent ventilation branch; S5-2: Start the ventilation system of the ventilation branch with priority level 2; S5-3: Start the ventilation system of the ventilation branch with priority level 3.

6. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 5 is characterized by: Step S5-2 includes: S5-2-1: Determine the start-up sequence of the ventilators (2); obtain the radon gas concentration at different locations of the ventilation branch through the radon gas detection sensor (6), and send it to the PLC control substation (4); the PLC control substation (4) preferentially drives the ventilator (2) at the location with the highest concentration, and sequentially starts the remaining ventilators (2) on both sides of the nearest ventilator (2), and the start-up interval between adjacent fans is ≥10 seconds, and dynamically monitors the air volume and radon gas concentration value of the adjacent ventilation branches; S5-2-2: Determine the operating frequency of each ventilator (2), and drive each ventilator (2) according to a starting sequence; The average value w of the radon gas outflow in the next period predicted in step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 '; Calculated using the following formula: Where Q i+1 ' is the average air volume required for the next period of the ventilation branch; S5-2-2-1: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-2-2-3; S5-2-2-2: Based on the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator (2) established in step S2-4, the operating frequency f of the ventilator of the ventilation branch is predicted. i+1 ; If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan (2), the PLC control substation (4) sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan (2) to n Hz; S5-2-2-3: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, execute S5-2-2-2; otherwise, run according to the current frequency.

7. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 5 is characterized by: Step S5-3 includes: S5-3-1: Determine the number and order of starting each ventilator (2) of the ventilation branch; maintain operation according to the lowest total power, shut down the redundant ventilators (2) of the ventilation branch, and give priority to starting the ventilator (2) with the shortest running time among all the ventilators (2) in the ventilation branch; if the running time is the same, rotate the ventilators (2) in the order of the number of the ventilators (2); S5-3-2: Determine the power sequence of the activated ventilators (2) of the ventilation branch; S5-3-2-1: The average value w of the radon gas outflow in the next period predicted according to step S3-2 i+1 ′ and the set radon concentration safety threshold C a , predict the average air volume Q required for the ventilation branch in the next period i+1 '; Calculated using the following formula: Where Q i+1 ' is the average air volume required for the next period of the ventilation branch; S5-3-2-2: If the ventilation branch is started for the first time, proceed to the next step; otherwise, proceed to S5-3-2-4; S5-3-2-3: Based on the functional relationship between the air volume of the ventilation branch and the operating frequency of the ventilator (2) established in step S2-4, the operating frequency f of the ventilator of the ventilation branch is predicted. i+1 ; If the predicted operating frequency f i+1 When the frequency is greater than the maximum operating frequency n Hz of the ventilation branch fan (2), the PLC control substation (4) sends an alarm signal to the PLC control main station and adjusts the operating frequency of the fan (2) to n Hz; S5-3-2-4: If the average air volume required for the next period is predicted to be Q i+1 ' is greater than or less than Q i 'The average air volume of the current period, then execute S5-3-2-3; otherwise, run according to the current frequency; S5-3-3: The radon gas concentration of the ventilation branch is obtained in real time through the PLC control substation (4), and the average value of the radon gas concentration of the ventilation branch is calculated, and the average value of the radon gas concentration is sent to the PLC control main station. If the average value of the radon gas concentration does not change, repeat this step; if the average value of the radon gas concentration changes, execute S3.

8. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 1 is characterized by: The ventilators (2) are spaced apart at a distance of 140 m, and the ventilators (2) are all fixed on the ground of the ventilation branch.

9. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 1 is characterized by: There are two radon gas detection sensors (6) at each radon gas detection point, and the two radon gas detection sensors (6) are installed vertically at intervals on the inner wall of the ventilation branch.

10. The method for controlling radon gas concentration in the operating gallery of a hydropower station and fan frequency conversion according to claim 1, characterized in that: The host computer monitoring platform is equipped with a priority scheduling module. The host computer monitoring platform and the PLC control main station communicate with each other using industrial Ethernet, and the PLC control substation (4) of each corridor and the PLC control main station use RS485 bus communication.

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