A "three out of two" logic algorithm for guide vane displacement signal of a hydraulic turbine governor

Abstract

The application discloses a kind of water turbine governor guide vane displacement signal " three selects two " logic algorithm, it includes the following steps: step 1: to water turbine governor guide vane displacement signal " three selects two " device is connected;Step 2: to the quality judgment of three sensors in water turbine governor guide vane displacement signal " three selects two " device;Step 3: in the case where three sensors are all without fault, to three sensors is compared with two two difference;According to the above steps, select two sensors from three sensors and output its signal;The purpose of the application is to solve the existing guide vane position sensor signal " three selects two " judgment method can only judge the sampling credibility of main sensor, after main sensor body damage, need to switch governor to reduce the influence of failure, thereby leading to the technical problem of lower failure redundancy, and provide a kind of water turbine governor guide vane displacement signal " three selects two " method.

Description

Technical Field

[0001] This invention belongs to the field of hydropower station unit technology, specifically relating to a "two-out-of-three" logic algorithm for the displacement signal of the turbine governor guide vane. Background Technology

[0002] The turbine servo displacement sensor reflects the opening degree of the turbine guide vanes. The guide vane opening degree determines the frequency (speed) variation of the turbine, and the reliability of its signal plays a crucial role in the stable operation of the unit. The servo displacement is acquired by local sensors and directly input to the governor's analog signal acquisition module via a shielded cable. The servo displacement sensor signal can quickly and directly reflect the servo travel, and the calculated guide vane opening value is a key control variable involved in the governor's PID calculation and control.

[0003] Currently, various hydropower station governor manufacturers offer a variety of different guide vane displacement sensor signal selection logics. These logics are relatively simple. For systems with two sets of guide vane displacement signals, high-order selection logic is often used. For systems with three sets of guide vane displacement signals, the selection logic compares the sensor deviation value with a set threshold.

[0004] Currently, the guide vane opening value is acquired by the governor controller of a hydropower station through displacement sensors measuring the stroke of the relay. Generally, a hydropower station governor is equipped with two or three sets of guide vane relay displacement sensors (hereinafter referred to as guide vane position sensors). Taking three sets as an example, they are labeled A, B, and C. Set A is used by governor A, set B by governor B, and set C serves as a common reference sensor. After receiving the guide vane position sensor signals, the governor A and B controllers exchange guide vane position signals via A / B communication. The guide vane position sensor signal from set C is transmitted to governor A and B controllers via a divider. Thus, each controller receives signals from all three sets of guide vane position sensors and uses a 3-to-2 multiplexer logic to verify the reliability of the received guide vane position sensor signals. The 3-to-2 multiplexer logic control structure is as follows: Figure 1 As shown.

[0005] For ease of explanation, sensor set A will be abbreviated as A, sensor set B as B, and reference sensor set C as C. The speed controller A uses sensor set A. To add fault detection for sensor A, the logic block diagram for a 3-to-2 selection is as follows: Figure 2 As shown:

[0006] If none of the three sensors have a feedback signal fault, and |AB| < the deviation setpoint or |AC| < the deviation setpoint, then set A is selected as the primary sensor. If |AB| > the deviation setpoint, |AC| > the deviation setpoint, or |BC| > the deviation setpoint, a sensor over-tolerance alarm is triggered. If both |AB| and |AC| > the deviation setpoint, then set A is judged to be faulty and an alarm is triggered, and the master / slave switching between controllers A and B is performed. For the guide vane opening signal, in the program calculation, controller A still uses the signal from the primary sensor connected to set A as the main signal source. The three-to-two selection logic only performs auxiliary judgment on the feasibility of signals from set A and set B, and does not affect the analog output result. The fault judgment logic for sensor B is the same as that for set A.

[0007] The "three-to-two" judgment logic for guide vane position sensor signals significantly improves the reliability of the primary sensor and provides a more reasonable fault diagnosis basis, supplementing the previous "two-to-one" logic. However, this "three-to-two" selection logic only judges the deviation values ​​of the two guide vane sensors against a set threshold. If the deviation values ​​of the two guide vane sensors are less than the set threshold, sensor A and sensor B are defaulted as the primary sensor outputs. This algorithm only judges the sampling reliability of the primary sensor based on the guide vane deviation value and does not change the output result of the primary sensor. After the primary sensor body is damaged, speed controller A will still be unable to monitor the actual guide vane opening value, and speed controllers A and B still need to be switched to reduce the impact of the fault, resulting in low fault redundancy. Summary of the Invention

[0008] The purpose of this invention is to solve the technical problem that the existing "two-out-of-three" judgment method for guide vane position sensor signals can only judge the sampling reliability of the main sensor. After the main sensor body is damaged, the governor needs to be switched to reduce the impact of the fault, resulting in low fault redundancy. The invention provides a "two-out-of-three" method for guide vane displacement signals of a turbine governor.

[0009] A logic algorithm for selecting two out of three displacement signals from the guide vane of a water turbine governor includes the following steps:

[0010] Step 1: Connect the wiring to the "three-to-two" device for the guide vane displacement signal of the turbine governor;

[0011] Step 2: Perform quality assessment on the three sensors in the "two-out-of-three" device for the displacement signal of the turbine governor guide vane;

[0012] Step 3: Assuming all three sensors are functioning correctly, perform pairwise difference comparisons between the three sensors.

[0013] Based on the above steps, select two sensors from the three sensors and output their signals to the governor AI channel for calculating the unit's guide vane opening.

[0014] In step 1, the "two out of three" device for the guide vane displacement signal of the turbine governor includes set A of guide vane position sensors, set B of guide vane position sensors, and set C of guide vane position sensors; the output end of set A of guide vane position sensors is connected to the input end of the first signal distributor, and the output ends of the first signal distributor are respectively connected to the input ends of the governor A machine controller and the governor B machine controller; the output end of set B of guide vane position sensors is connected to the input end of the second signal distributor, and the output ends of the second signal distributor are respectively connected to the input ends of the governor A machine controller and the governor B machine controller; the output end of set C of guide vane position sensors is connected to the input end of the third signal distributor, and the output ends of the third signal distributor are respectively connected to the input ends of the governor A machine controller and the governor B machine controller.

[0015] In step 3, when making pairwise difference comparisons, the difference between set A of guide vane position sensors and set B of guide vane position sensors is represented by Yab, the difference between set A of guide vane position sensors and set C of guide vane position sensors is represented by Yac, and the difference between set B of guide vane position sensors and set C of guide vane position sensors is represented by Ybc. At this time, Yab, Yac, and Ybc are further compared with the preset deviation value Yp of the sensor. If Yab > Yp, record the true value of Yab as 1; if Yab < Yp, record the true value of Yab as 0; if Yac > Yp, record the true value of Yac as 1; if Yac < Yp, record the true value of Yac as 0; if Ybc > Yp, record the true value of Ybc as 1; if Ybc < Yp, record the true value of Ybc as 0.

[0016] In step 3, as Figure 4 shown, the judgment steps are as follows:

[0017] 1) First, judge whether Yab is greater than Yp. If Yab > Yp, then judge whether Ybc is greater than Yp. If Ybc > Yp, then continue to judge whether Yac is greater than Yp. If Yac > Yp, it is determined that there is a large deviation fault in the sensor, and the sensor value remains unchanged before the fault; if Yac < Yp, it is determined that there is a fault in set B of guide vane position sensors, and the signal outputs of set A and set C of guide vane position sensors.

[0018] 2) If it is determined that Yab > Yp, then judge whether Ybc is greater than Yp. If it is determined that Ybc < Yp, then continue to judge whether Yac is greater than Yp. If Yac > Yp, it is determined that there is a fault in set A of guide vane position sensors, and the signal outputs of set B and set C of guide vane position sensors; if Yac < Yp, it is determined that the deviation between set A and set B of guide vane position sensors is large, and the signal output of set C of guide vane position sensors.

[0019] 3) Determine that Yab < Yp, then check if Ybc is greater than Yp. If it is determined that Ybc > Yp, then continue to check if Yac is greater than Yp. If Yac > Yp, then it is determined that the C set of guide vane position sensors fails, and the sampling values of the A and B sets of guide vane position sensors are output; if Yac < Yp, then the deviation between the B and C sets of guide vane position sensors is large, and the signal of the A set of guide vane position sensors is output.

[0020] 4) Determine that Yab < Yp, then check if Ybc is greater than Yp. If it is determined that Ybc < Yp, then continue to check if Yac is greater than Yp. If Yac > Yp, then it is determined that the deviation between the A and C sets of guide vane position sensors is large, and the signal of the B set of guide vane position sensors is output; if Yac < Yp, then there is no deviation fault, and the judgment process jumps to S1 to enter the parameter optimization judgment, as Figure 5 shown.

[0021] In step 2, if Yab < Yp, Yac < Yp, and Ybc < Yp, that is, the deviations of the A, B, and C sets of guide vane position sensors are all within the deviation threshold range. By comparing the magnitudes of Yab, Yac, and Ybc, arrange them in descending order;

[0022] The total number of sorting methods that can be obtained is as follows: Yab > Yac > Ybc, Yab > Ybc > Yac, Yac > Ybc > Yab, Yac > Yab > Ybc, Ybc > Yac > Yab, Ybc > Yab > Yac, a total of 6 sorting methods;

[0023] Remove the one with the largest difference between the output value and the other two among the three sensors, and select the remaining two for output, specifically as follows;

[0024] (1) If the sorting method is Yab > Yac > Ybc or Yac > Yab > Ybc, then remove the A set of guide vane position sensors and select the B and C sets of guide vane position sensors for output;

[0025] (2) If the sorting method is Yab > Ybc > Yac or Ybc > Yab > Yac, then remove the B set of guide vane position sensors and select the A and C sets of guide vane position sensors for output;

[0026] (3) If the sorting method is Yac > Ybc > Yab or Ybc > Yac > Yab, then remove the C set of guide vane position sensors and select the A and B sets of guide vane position sensors for output.

[0027] In step 3, as Figure 5 shown, the judgment steps are as follows:

[0028] 1) First, determine whether Yab is greater than Yac. If Yab > Yac, then determine whether Yac is greater than Ybc. If Yac > Ybc, it is determined that Yab > Yac > Ybc, and then the guide vane position sensor of set A is removed, and the outputs of the guide vane position sensors of set B and set C are selected;

[0029] 2) If it is determined that Yab > Yac, then determine whether Yac is greater than Ybc. If Yac < Ybc, then continue to determine whether Yab is greater than Ybc. If Yab > Ybc, it is determined that Yab > Ybc > Yac; if Yab < Ybc, it is determined that Ybc > Yab > Yac, and then the guide vane position sensor of set B is removed, and the outputs of the guide vane position sensors of set A and set C are selected;

[0030] 3) If it is determined that Yab < Yac, then determine whether Yab is greater than Ybc. If Yab > Ybc, it is determined that Yac > Yab > Ybc, and then the guide vane position sensor of set A is removed, and the outputs of the guide vane position sensors of set B and set C are selected;

[0031] 4) If it is determined that Yab < Yac, then determine whether Yab is greater than Ybc. If Yab < Ybc, then continue to determine whether Yac is greater than Ybc. If Yac > Ybc, it is determined that Yac > Ybc > Yab; if Yac < Ybc, it is determined that Ybc > Yac > Yab, and then the guide vane position sensor of set C is removed, and the outputs of the guide vane position sensors of set A and set B are selected.

[0032] In step 2, when judging the quality of the three sensors, if one or more of the faults such as "broken wire", "out-of-limit", dead value, and jump change are found in the sensors, a fault determination is made, and the sensors marked as "fault" are excluded.

[0033] Compared with the prior art, the present invention has the following technical effects:

[0034] The present invention proposes a new "two-out-of-three" logic algorithm for the guide vane displacement signal of a hydroturbine governor. This logic algorithm compares the sampling values of three guide vane displacement sensors with a preset deviation threshold. Within the range of satisfying the deviation threshold, through the deviation calculation values of two sensors, the two sets of sensor sampling values with the smallest error are selected for output, and the sensor sampling values are always output from the same sensor. By judging the preferred logic, the most authentic and reliable sensor sampling values are screened out. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following further illustrates the present invention in conjunction with the drawings and embodiments:

[0036] Figure 1 It is the "two-out-of-three" logic control structure diagram of the unit governor in the prior art;

[0037] Figure 2 This is a logic block diagram of the "two-out-of-three" configuration for generator units in existing technology.

[0038] Figure 3 This is a schematic diagram of the "three-to-two" displacement signal selection device for the turbine governor guide vane in this invention;

[0039] Figure 4 This is a flowchart of the "three-to-two" logic sensor deviation threshold judgment process in this invention;

[0040] Figure 5 This is a flowchart of the "two-out-of-three" logic sensor selection process in this invention. Detailed Implementation

[0041] like Figures 1 to 5 As shown, a "three-to-two" logic algorithm for the displacement signal of the guide vane of a water turbine governor includes the following steps:

[0042] Step 1: Connect the wiring to the "three-to-two" device for the guide vane displacement signal of the turbine governor;

[0043] Step 2: Perform quality assessment on the three sensors in the "two-out-of-three" device for the displacement signal of the turbine governor guide vane;

[0044] Step 3: Assuming all three sensors are functioning correctly, perform pairwise difference comparisons between the three sensors.

[0045] Based on the above steps, select two sensors from the three sensors and output their signals to the governor AI channel for calculating the unit's guide vane opening.

[0046] In step 1, the "two-out-of-three" device for the turbine governor guide vane displacement signal includes a set of guide vane position sensors 1 (A set), 2 (B set), and 3 (C set). The output of the guide vane position sensor 1 (A set) is connected to the input of the first signal distributor 4, and the output of the first signal distributor 4 is connected to the inputs of the governor A controller 7 and the governor B controller 8, respectively. The output of the guide vane position sensor 2 (B set) is connected to the input of the second signal distributor 5, and the output of the second signal distributor 5 is connected to the inputs of the governor A controller 7 and the governor B controller 8, respectively. The output of the guide vane position sensor 3 (C set) is connected to the input of the third signal distributor 6, and the output of the third signal distributor 6 is connected to the inputs of the governor A controller 7 and the governor B controller 8, respectively.

[0047] In step 2, when the quality of the three sensors is judged, if one or more of the following faults are found: "open wire", "out of limit", dead value, or jump, a fault determination is made and the sensor marked as "faulty" is removed.

[0048] In step 3, when making pairwise difference comparisons, the difference between the guide vane position sensors of set A and set B is represented by Yab, the difference between the guide vane position sensors of set A and set C is represented by Yac, and the difference between the guide vane position sensors of set B and set C is represented by Ybc. At this time, Yab, Yac, and Ybc are compared with the preset deviation value Yp of the sensor. If Yab > Yp, record the true value of Yab as 1; if Yab < Yp, record the true value of Yab as 0; if Yac > Yp, record the true value of Yac as 1; if Yac < Yp, record the true value of Yac as 0; if Ybc > Yp, record the true value of Ybc as 1; if Ybc < Yp, record the true value of Ybc as 0.

[0049] The true value lists of Yab, Yac, and Ybc are as follows:

[0050] Yab>Yp Yac>Yp Ybc>Yp Alarm output Sensor sample value output 0 0 0 No alarm Three-choice-two-optimized-output 0 0 1 Large deviation of sensor BC Sensor A output 0 1 0 Large AC deviation of the sensor Sensor B output 0 1 1 Sensor C fault Sensors A and B output 1 0 0 Large AB deviation of the sensor Sensor C output 1 0 1 Sensor B malfunction Sensor A and C outputs 1 1 0 Sensor A fault Sensors B and C output 1 1 1 Sensor total deviation Sensor failure pre-failure value

[0051] In step 3, as Figure 4 shown, the judgment steps are as follows:

[0052] 1) First, judge whether Yab is greater than Yp. If Yab > Yp, then judge whether Ybc is greater than Yp. If Ybc > Yp, then continue to judge whether Yac is greater than Yp. If Yac > Yp, it is determined that there is a large deviation fault in the sensor, and the sensor value remains unchanged before the fault; if Yac < Yp, it is determined that there is a fault in the guide vane position sensor of set B, and the signal outputs of the guide vane position sensors of set A and set C.

[0053] 2) If it is determined that Yab > Yp, then judge whether Ybc is greater than Yp. If it is determined that Ybc < Yp, then continue to judge whether Yac is greater than Yp. If Yac > Yp, it is determined that there is a fault in the guide vane position sensor of set A, and the signal outputs of the guide vane position sensors of set B and set C; if Yac < Yp, it is determined that the deviation between the guide vane position sensors of set A and set B is large, and the signal output of the guide vane position sensor of set C.

[0054] 3) If it is determined that Yab < Yp, then judge whether Ybc is greater than Yp. If it is determined that Ybc > Yp, then continue to judge whether Yac is greater than Yp. If Yac > Yp, it is determined that there is a fault in the guide vane position sensor of set C, and the sampled values of the guide vane position sensors of set A and set B are output; if Yac < Yp, the deviation between the guide vane position sensors of set B and set C is large, and the signal output of the guide vane position sensor of set A.

[0055] 4) Determine that Yab < Yp, then determine whether Ybc is greater than Yp. If it is determined that Ybc < Yp, then continue to determine whether Yac is greater than Yp. If Yac > Yp, then it is determined that there is a large deviation between the guide vane position sensors of set A and set C, and the signal of the guide vane position sensor of set B is output; if Yac < Yp, then there is no deviation fault, and the judgment process jumps to S1 to enter the parameter optimization judgment, as Figure 5 shown.

[0056] In step 3, if Yab < Yp, Yac < Yp, and Ybc < Yp, that is, the deviations of the guide vane position sensors of set A, set B, and set C are all within the deviation threshold range, compare the magnitudes of Yab, Yac, and Ybc and arrange them from largest to smallest;

[0057] The total sorting methods that can be obtained are as follows: Yab > Yac > Ybc, Yab > Ybc > Yac, Yac > Ybc > Yab, Yac > Yab > Ybc, Ybc > Yac > Yab, Ybc > Yab > Yac, a total of 6 sorting methods;

[0058] Remove the one with the largest difference between the output value and the other two among the three sensors, and select the remaining two for output, specifically as follows;

[0059] (1) If the sorting method is Yab > Yac > Ybc or Yac > Yab > Ybc, then remove the guide vane position sensor of set A and select the guide vane position sensors of set B and set C for output;

[0060] (2) If the sorting method is Yab > Ybc > Yac or Ybc > Yab > Yac, then remove the guide vane position sensor of set B and select the guide vane position sensors of set A and set C for output;

[0061] (3) If the sorting method is Yac > Ybc > Yab or Ybc > Yac > Yab, then remove the guide vane position sensor of set C and select the guide vane position sensors of set A and set B for output.

[0062] In step 3, as Figure 5 shown, the judgment steps are as follows:

[0063] 1) First, determine whether Yab is greater than Yac. If Yab > Yac, then determine whether Yac is greater than Ybc. If Yac > Ybc, it is determined as Yab > Yac > Ybc, then remove the guide vane position sensor of set A and select the guide vane position sensors of set B and set C for output;

[0064] 2) Determine that Yab > Yac, then judge whether Yac is greater than Ybc. If Yac < Ybc, then continue to judge whether Yab is greater than Ybc. If Yab > Ybc, then determine that Yab > Ybc > Yac; if Yab < Ybc, then determine that Ybc > Yab > Yac, then remove the B set of guide vane position sensors and select the outputs of the A set of guide vane position sensors and the C set of guide vane position sensors.

[0065] 3) Determine that Yab < Yac, then judge whether Yab is greater than Ybc. If Yab > Ybc, then determine that Yac > Yab > Ybc, then remove the A set of guide vane position sensors and select the outputs of the B set of guide vane position sensors and the C set of guide vane position sensors.

[0066] 4) Determine that Yab < Yac, then judge whether Yab is greater than Ybc. If Yab < Ybc, then continue to judge whether Yac is greater than Ybc. If Yac > Ybc, then determine that Yac > Ybc > Yab; if Yac < Ybc, then determine that Ybc > Yac > Yab, then remove the C set of guide vane position sensors and select the outputs of the A set of guide vane position sensors and the B set of guide vane position sensors.

[0067] The "two out of three" logic algorithm for the guide vane displacement signal of the hydraulic turbine governor proposed by the present invention first performs channel quality judgment on the sampling values of the three sets of sensors to exclude faulty sensors; then calculates the guide vane deviation value through the comparison of the sampling values of two sensors, and compares the guide vane deviation value with the artificially set deviation threshold to eliminate the sensor with a large deviation; finally, the sampling values of the three sets of sensors are optimized, and the sensor with a large deviation from the sampling values of the other two sets among the three sets of sensors is eliminated, and finally the sampling values of two sensors with similar deviations are output.

[0068] This invention judges from the single-channel quality of the signal to the deviation judgment of the sampling values of each channel, eliminates the sensors with larger deviation from the sampling values, and finally selects the sensors with more real and reliable sampling values for output. Through comprehensive intelligent judgment and algorithms, this logic optimizes and outputs the signal of the guide vane position sensor that is more real and reliable among the three sets of sensors. The final output of the guide vane position sensor signal is not affected by the withdrawal of any one of the sensors.

Claims

1. A method for optimizing guide vane displacement signal of a hydro-turbine governor, characterized in that, It includes the following steps: Step 1: Connect the "two-out-of-three" device for the guide vane displacement signal of the turbine governor. Step 2: Judge the quality of the three sensors in the "two-out-of-three" device for the guide vane displacement signal of the turbine governor. Step 3: When all three sensors are free of faults, compare the differences between every two of the three sensors. Select two sensors from the three sensors according to the above steps and output their signals. In Step 1, the "two-out-of-three" device for the guide vane displacement signal of the turbine governor includes Guide Vane Position Sensor Set A (1), Guide Vane Position Sensor Set B (2), and Guide Vane Position Sensor Set C (3); the output end of Guide Vane Position Sensor Set A (1) is connected to the input end of the First Signal Distributor (4), and the output ends of the First Signal Distributor (4) are respectively connected to the input ends of Governor A Controller (7) and Governor B Controller (8); the output end of Guide Vane Position Sensor Set B (2) is connected to the input end of the Second Signal Distributor (5), and the output ends of the Second Signal Distributor (5) are respectively connected to the input ends of Governor A Controller (7) and Governor B Controller (8); the output end of Guide Vane Position Sensor Set C (3) is connected to the input end of the Third Signal Distributor (6), and the output ends of the Third Signal Distributor (6) are respectively connected to the input ends of Governor A Controller (7) and Governor B Controller (8). In Step 3, when comparing the differences between every two, the difference between Guide Vane Position Sensor Set A and Guide Vane Position Sensor Set B is represented by Yab, the difference between Guide Vane Position Sensor Set A and Guide Vane Position Sensor Set C is represented by Yac, and the difference between Guide Vane Position Sensor Set B and Guide Vane Position Sensor Set C is represented by Ybc. At this time, compare Yab, Yac, and Ybc with the preset deviation value Yp of the sensor. If Yab>Yp, record the true value of Yab as 1. If Yab<Yp, record the true value of Yab as 0. If Yac>Yp, record the true value of Yac as 1. If Yac<Yp, record the true value of Yac as 0. If Ybc>Yp, record the true value of Ybc as 1. If Ybc<Yp, record the true value of Ybc as 0. In Step 3, the comparison steps are as follows: 1) First, judge whether Yab is greater than Yp. If Yab>Yp, then judge whether Ybc is greater than Yp. If Ybc>Yp, then continue to judge whether Yac is greater than Yp. If Yac>Yp, it is determined that there is a large deviation fault in the sensor, and the sensor value remains unchanged before the fault. If Yac<Yp, it is determined that there is a fault in Guide Vane Position Sensor Set B, and the signals of Guide Vane Position Sensor Set A and Guide Vane Position Sensor Set C are output. 2) If it is determined that Yab>Yp, then judge whether Ybc is greater than Yp. If it is determined that Ybc<Yp, then continue to judge whether Yac is greater than Yp. If Yac>Yp, it is determined that there is a fault in Guide Vane Position Sensor Set A, and the signals of Guide Vane Position Sensor Set B and Guide Vane Position Sensor Set C are output. If Yac<Yp, it is determined that there is a large deviation between Guide Vane Position Sensor Set A and Guide Vane Position Sensor Set B, and the signal of Guide Vane Position Sensor Set C is output. 3) If it is determined that Yab < Yp, then check whether Ybc is greater than Yp. If it is determined that Ybc > Yp, then continue to check whether Yac is greater than Yp. If Yac > Yp, then it is determined that the C set of guide vane position sensors fails, and the sampled values of the A and B sets of guide vane position sensors are output; if Yac < Yp, then the deviation between the B and C sets of guide vane position sensors is large, and the signal of the A set of guide vane position sensors is output. 4) If it is determined that Yab < Yp, then check whether Ybc is greater than Yp. If it is determined that Ybc < Yp, then continue to check whether Yac is greater than Yp. If Yac > Yp, then it is determined that the deviation between the A and C sets of guide vane position sensors is large, and the signal of the B set of guide vane position sensors is output; if Yac < Yp, then there is no deviation fault, and proceed to the next comparison.

2. The method of claim 1, wherein, In step 3, if Yab < Yp, Yac < Yp, and Ybc < Yp, that is, the deviations of the A set of guide vane position sensors, the B set of guide vane position sensors, and the C set of guide vane position sensors are all within the deviation threshold range. By comparing the magnitudes of Yab, Yac, and Ybc, arrange them in descending order. The total number of sorting methods that can be obtained is as follows: Yab > Yac > Ybc, Yab > Ybc > Yac, Yac > Ybc > Yab, Yac > Yab > Ybc, Ybc > Yac > Yab, Ybc > Yab > Yac, a total of 6 sorting methods. Remove the one with the largest difference between the output value of one of the three sensors and the other two, and select the remaining two for output, specifically as follows: (1) If the sorting method is Yab > Yac > Ybc or Yac > Yab > Ybc, then remove the A set of guide vane position sensors and select the B set of guide vane position sensors and the C set of guide vane position sensors for output. (2) If the sorting method is Yab > Ybc > Yac or Ybc > Yab > Yac, then remove the B set of guide vane position sensors and select the A set of guide vane position sensors and the C set of guide vane position sensors for output. (3) If the sorting method is Yac > Ybc > Yab or Ybc > Yac > Yab, then remove the C set of guide vane position sensors and select the A set of guide vane position sensors and the B set of guide vane position sensors for output.

3. The method of claim 2, wherein, In step 3, the comparison steps are as follows: 1) First, check whether Yab is greater than Yac. If Yab > Yac, then check whether Yac is greater than Ybc. If Yac > Ybc, it is determined as Yab > Yac > Ybc, then remove the A set of guide vane position sensors and select the B set of guide vane position sensors and the C set of guide vane position sensors for output. 2) If it is determined that Yab > Yac, then check whether Yac is greater than Ybc. If Yac < Ybc, then continue to check whether Yab is greater than Ybc. If Yab > Ybc, it is determined as Yab > Ybc > Yac; if Yab < Ybc, it is determined as Ybc > Yab > Yac, then remove the B set of guide vane position sensors and select the A set of guide vane position sensors and the C set of guide vane position sensors for output. 3) Determine that Yab < Yac, then judge whether Yab is greater than Ybc. If Yab > Ybc, then determine that Yac > Yab > Ybc, and remove the A set of guide vane position sensors, and select the outputs of the B set of guide vane position sensors and the C set of guide vane position sensors. 4) Determine that Yab < Yac, then judge whether Yab is greater than Ybc. If Yab < Ybc, then continue to judge whether Yac is greater than Ybc. If Yac > Ybc, then determine that Yac > Ybc > Yab; if Yac < Ybc, then determine that Ybc > Yac > Yab, and remove the C set of guide vane position sensors, and select the outputs of the A set of guide vane position sensors and the B set of guide vane position sensors.

4. The method according to claim 1, characterized in that, In step 2, when judging the quality of the three sensors, if one or more of the faults of "broken wire", "out-of-limit", dead value, and jump change are found in the sensors, a fault determination is made, and the sensors marked as "fault" are excluded.

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