Method and system for judging main distributing twitching fault of FC main distributing valve

Abstract

The invention discloses a method and a system for judging a main distributing twitching fault of an FC (Fiber Channel) main distributing valve, which are used for monitoring the state of a valve core of the main distributing valve, collecting signals through a displacement sensor, analyzing the law of the collected signals, fitting and matching with twitching characteristics, and identifying and judging according to set parameters. And finally, the main and distribution valve element twitching fault is accurately and timely judged. And support is provided for fault switching and redundancy of the water turbine governor system. According to the method for judging the master-slave twitch fault, the master-slave twitch fault can be automatically and rapidly diagnosed, redundancy switching of the master / slave controller is carried out, stability of a control system can be rapidly recovered, accident expansion is prevented, safe and stable operation of a unit is guaranteed, and the method has important significance.

Description

Technical Field

[0001] The invention relates to a control technology of a main pressure regulating valve of a turbine speed regulator, and in particular to a method and a system for judging a main pressure regulating valve twitching fault of an FC main pressure regulating valve. Background Art

[0002] The control of the turbine mainly relies on the speed governor, and one of the core devices of the speed governor is the main pressure regulating valve. The main pressure regulating valve is a mechanical hydraulic amplification mechanism, and the basic structure includes a valve body, a valve sleeve and a valve core. There are many types of main pressure regulating valves. The commonly used FC valve has a large internal oil pressure leakage and is more common. During the operation of the unit, the main pressure regulating valve will cause the relay to reciprocate, eventually causing power fluctuations, causing unstable power output of the unit, and even affecting the safety of the power grid.

[0003] At present, most speed governors in the industry do not have special monitoring and fault judgment for the main distribution valve core twitching. Some power stations use the method of using the main distribution valve core displacement sensor to count back and forth. If the number of times reaches the specified time, it is considered that the main distribution is twitching. This method is inaccurate, and the characteristic analysis of the twitching is insufficient. When the measurement data of the unit operation characteristics has a gross error, it is easy to make a misjudgment, and at the same time affect the calculation accuracy of all parameters in the surrounding grid.

[0004] Therefore, it is necessary to develop a method for judging the twitching fault of the main distribution valve core according to the twitching characteristics. Summary of the invention

[0005] Purpose of the invention: In order to solve the problems of inaccurate twitching fault judgment and insufficient twitching feature analysis in existing methods, which are prone to misjudgment, the present invention discloses a method and system for fault judgment based on sampling statistics by identifying the twitching characteristics of the main valve core.

[0006] Technical solution: The present invention discloses a method for judging the main distribution twitching fault of the FC main distribution pressure valve, the method comprising the following steps:

[0007] Step 1: Connect the main pressure distribution valve spool displacement signal to the detection device and define the spool opening position threshold θ 开 , Close position threshold θ 关 , set the detection cycle and start the timer;

[0008] Step 2: In one detection cycle, detect the relationship between the valve core position and the threshold value, and record the total number of times the valve core reaches the open and closed position thresholds;

[0009] Step 3: within a detection cycle, draw a displacement-time curve of the valve core to detect the twitching frequency and the deviation of the frequencies of two adjacent twitchings;

[0010] Step 4: According to the test results obtained in step 2 and step 3, determine whether the twitching fault condition is met. If the test results obtained in step 2 and step 3 are both met, output a main pressure distribution twitching fault signal to the main pressure distribution valve control end; if not met, reset the timer, return to step 2, and restart the test.

[0011] Furthermore, step 1 defines the fully open position of the valve core as 100%, the fully closed position as -100%, and the center position as 0. On this basis, the displacement of the valve core is positioned in the form of percentage, and θ 开 >0>θ 关 .

[0012] Furthermore, the detection of the relationship between the valve core position and the threshold value in step 2 is to simultaneously detect the relationship between the valve core displacement and the open and closed position thresholds within one detection cycle.

[0013] The specific process of detecting the relationship between the valve core position and the open position threshold is as follows: If the valve core displacement value is greater than the set value θ 开 , set a Boolean variable A to 1, which is less than θ 开 When A returns to 0, and the valve core displacement is greater than θ 开 Once, the integer variable B is incremented by 1.

[0014] The specific process of detecting the relationship between the valve core position and the closed position threshold is as follows: If the valve core displacement value is less than the set value θ 关 , set a Boolean variable C to 1, which is greater than θ 关 When C returns to 0, and the valve core displacement is less than θ 关 Once, the integer variable D is incremented by 1.

[0015] Furthermore, the adjacent means in step 3 means that the time interval between two twitches is less than half a twitch cycle.

[0016] Furthermore, the specific method of determining whether the detection result of step 2 meets the twitching fault condition in step 4 is to set a twitching number threshold γ. Within one detection cycle, if the cumulative values ​​of B and D are greater than γ, and the absolute value of the deviation of BD is less than 3, then the detection result of step 2 meets the twitching fault condition; if the twitching fault condition is not met within one detection cycle, wait for the timer to refresh.

[0017] Furthermore, the specific method of determining whether the detection result of step 3 satisfies the twitching fault condition in step 4 is to set the empirical frequency range and the frequency deviation threshold α. Within a detection cycle, if the twitching frequency is within the empirical frequency range and the absolute value of the adjacent frequency deviation is less than α, then the detection result of step 3 satisfies the twitching fault condition; if the twitching fault condition is not met within a detection cycle, then wait for the timer to refresh.

[0018] Furthermore, after step 4 outputs the main pressure regulating valve twitching fault signal to the main pressure regulating valve control end, the turbine speed governor corresponding to the main pressure regulating valve switches control, starts the backup equipment, and cuts off the fault point.

[0019] The present invention also discloses a judgment system for a main distribution twitching fault of a FC main distribution pressure valve, which is characterized by comprising:

[0020] Preparation module, used to connect the main pressure distribution valve spool displacement signal to the detection device and define the spool opening position threshold θ 开 , Close position threshold θ 关 , set the detection cycle and start the timer;

[0021] The twitch frequency detection module is used to detect the relationship between the valve core position and the threshold value within a detection cycle, and record the total number of times the valve core reaches the open and closed position thresholds;

[0022] A twitching frequency detection module is used to draw a displacement-time curve of the valve core within a detection cycle, and detect the twitching frequency and the deviation of adjacent twitching frequencies;

[0023] The fault judgment module is used to judge whether the twitching fault conditions are met based on the detection results obtained in the twitching number detection module and the twitching frequency detection module. If the detection results obtained by the aforementioned modules are all met, the main and auxiliary twitching fault signal is output; if not, the timer is reset and the detection is restarted.

[0024] Beneficial effects: The present invention proposes a method and system for judging the main distribution twitching fault of the FC main distribution pressure valve. The method collects signals through a displacement sensor, analyzes the rules of the collected signals, fits and matches them with the twitching characteristics, and identifies and judges according to the set parameters, and finally obtains accurate and timely judgment of the main distribution valve core twitching fault.

[0025] The present invention discloses a method for judging a twitching fault of a main distribution valve core according to twitching characteristics, which can effectively monitor the stability of the main distribution valve, thereby accurately and timely reporting faults and reducing the risk of faults in unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the FC main pressure regulating valve.

[0027] Figure 2 It is a flow chart of an embodiment of a method for judging a main distribution twitching fault of a FC main distribution pressure valve according to the present invention.

[0028] Figure 3 It is a schematic diagram of the main valve core twitching recording curve-amplitude discrimination.

[0029] Figure 4It is a schematic diagram of the main valve core twitching recording curve-periodic characteristics judgment. DETAILED DESCRIPTION

[0030] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0031] like Figure 1 The figure shows the structure of the FC main pressure regulating valve. The control of the turbine mainly relies on the speed governor, and one of the core devices of the speed governor is the main pressure regulating valve. The main pressure regulating valve is a mechanical hydraulic amplification mechanism, including a valve body, a valve sleeve and a valve core. The main pressure regulating valve twitching refers to the main pressure regulating valve making up and down or left and right reciprocating movements relative to a reference point. The parameters that characterize its characteristics include the twitching cycle and the twitching amplitude.

[0032] like Figure 2 The flowchart of the method for judging the main distribution twitching fault of the FC main distribution pressure valve according to a specific embodiment of the present invention is shown. The specific steps of the method will be described below in conjunction with the embodiment.

[0033] Step 1: Connect the main pressure distribution valve spool displacement signal to the detection device and define the spool opening position threshold θ 开 , Close position threshold θ 关 , set the detection cycle and start the timer.

[0034] This embodiment introduces the main and distribution valve core position feedback signal into two sets of controllers, and uses programming language to implement the recognition algorithm of feedback signal alternation. The prerequisites for the adaptation of the main and distribution pumping intelligent diagnosis are: the unit is in "autonomous state", "generating state or no-load state", "no external pulse increase or decrease signal", and "primary frequency modulation is not in action".

[0035] In this embodiment, the two extreme positions of the main distribution valve core, open and closed, are first located and calibrated in percentage, that is, the main distribution fully open position is sampled and recorded as Semple_Open; the main distribution fully closed position is sampled and recorded as Semple_Close; the center position is sampled and recorded as Semple_Zero.

[0036] Therefore, assuming that the real-time sampling is Real_Time_Semple, we have

[0037] Percentage of travel in open direction:

[0038] y_open=(Real_Time_Semple-Semple_Open) / (Semple_Open-Semple_Zero)

[0039] Percentage of travel in closing direction:

[0040] y_Close=(Real_Time_Semple-Semple_Close) / (Semple_Close-Semple_Zero)

[0041] Step 2: In one detection cycle, detect the relationship between the valve core position and the threshold value, and record the total number of times the valve core reaches the open and closed position thresholds. Set the amplitude of the opening and closing directions of the twitch, and within the specified time, refer to the inherent characteristics of the mechanical twitch, and use the number accumulation method for both the opening and closing directions; and when the cumulative number deviation in the two directions is less than a certain threshold, it is considered to be one of the characteristics of the twitch.

[0042] Step 3: Draw the displacement-time curve of the valve core within a detection cycle, and detect the twitching frequency and the adjacent twitching frequency deviation. Adjacent means that the time interval between two twitches is less than half a detection cycle. Identify the twitching cycle of the valve core, set the twitching frequency within a certain range based on experience within the specified time, and continuously compare the adjacent frequency deviations. If the deviation is less than the threshold, it is considered to be one of the characteristics of twitching.

[0043] Step 4: According to the test results obtained in step 2 and step 3, determine whether the twitching fault condition is met. If the test results obtained in step 2 and step 3 are both met, output the main valve core twitching fault signal; if not, reset the timer, return to step 2, and restart the test.

[0044] Figure 3 It is a schematic diagram showing the determination of the detection result obtained in step 2 in step 4. In this embodiment, the detection period is set to 20 seconds, the twitch number threshold is Γ, and the opening direction and closing direction positions are detected simultaneously.

[0045] Open direction counting method: If the open direction value is greater than the set value θ 开 , a Boolean variable A becomes 1, and when it is less than this value, A returns to 0; each time it is greater than the set value θ 开 , an integer variable B is accumulated once.

[0046] Closing direction counting method: If the closing direction value is less than the set value θ 关 , a Boolean variable C becomes 1, and when it is greater than this value, C returns to 0; each time it is less than the set value θ 关 , an integer variable D is accumulated once.

[0047] In this way, if both B and D are greater than Γ within 20 seconds, and the deviation between B and D is less than 3, then the test result obtained in step 2 is judged to meet the twitching fault condition. If both B and D are not greater than Γ within 20 seconds, or the deviation between the cumulative number of opening direction and the cumulative number of closing direction is greater than 3 times, it is deemed that the twitching fault condition is not met.

[0048] The schematic procedure is as follows:

[0049]

[0050]

[0051] In step 4, the theoretical basis for judging the test results obtained in step 3 is that the twitching of the main distribution valve core is periodic. According to the mechanical characteristics of the main distribution valve core itself, it is a low-frequency twitching, and its twitching frequency is within a fixed range. The common twitching frequency is 2 times / s-1 time / 2s, that is, the empirical frequency range is 0.5Hz-2Hz. In practice, the speed governor configuration of each unit is different, and the jitter frequency is also different.

[0052] like Figure 4 As shown, the time of one twitching cycle is between 0.5s and 2s. If it is less than 0.5s, it means that the sampling has jumped and distorted, and it is not a mechanical twitch. If it is greater than 2s, it means that there is a problem with the relay of the main pressure distribution valve, resulting in a large-scale adjustment of the main distribution, which is not within the scope of main distribution fault judgment.

[0053] Therefore, based on the valve core twitching frequency, the logic for judging whether the valve core has a main distribution twitching fault is to draw a twitching curve based on the real-time sampling data within a detection cycle, and record the time point when the valve core crosses the center position for the nth time as t n , the total number of times crossing the center position is N, and the time difference between each two time points is recorded as T n ,have

[0054] T n =t n+2 -t n ,n∈[1,N]

[0055] Detection of twitch frequency F i Whether it is within the empirical frequency range, and at the same time judge whether two adjacent T n Is the frequency deviation less than the set value α? i Within the empirical frequency range and between two adjacent T n The frequency deviation is less than α, which means that the detection result of step 3 satisfies the twitching fault condition.

[0056] Assuming the detection period is 30s, and the total number of times N of crossing the center position is 12, the schematic procedure is as follows:

[0057]

[0058]

[0059] According to the detection results obtained in the above steps 2 and 3, the twitching amplitude and twitching frequency are judged in step 4, thereby outputting a twitching fault signal. After receiving the output fault signal, the turbine governor control switches to the backup device and working mode, removes the fault point, and ensures the overall stability of the governor system.

[0060] The twitch amplitude, cumulative number of times, cumulative number of times deviation, and frequency deviation involved in the present invention are all variable and can be set and adjusted according to actual conditions.

[0061] The present invention extracts and analyzes the twitching characteristics of the main pressure distribution valve of the speed regulator, and compares the cumulative number of twitching, the twitching frequency, and the deviation of the twitching frequency before and after according to the empirical frequency and amplitude of the twitching of the main distribution valve core, thereby accurately identifying the twitching characteristics and faults. Accurate identification of the main distribution twitching fault can assist the speed regulator in fault redundancy switching and ensure the long-term safe and stable operation of the hydropower unit.

Claims

1. A method for judging the main distribution twitching failure of the FC main distribution valve, characterized in that: The method comprises the following steps: Step 1: Connect the main pressure distribution valve spool displacement signal to the detection device and define the spool opening position threshold θ 开 , Close position threshold θ 关 , set the detection cycle and start the timer; Step 2: In one detection cycle, detect the relationship between the valve core position and the threshold value, and record the total number of times the valve core reaches the open and closed position thresholds; Step 3: within a detection cycle, draw a displacement-time curve of the valve core to detect the twitching frequency and the deviation of the frequencies of two adjacent twitchings; Step 4: According to the test results obtained in step 2 and step 3, determine whether the twitching fault condition is met. If the test results obtained in step 2 and step 3 are both met, output a main pressure distribution twitching fault signal to the main pressure distribution valve control end; if not met, reset the timer, return to step 2, and restart the test.

2. The method for determining a twitching fault according to claim 1, characterized in that: Step 1 defines the fully open position of the valve core as 100%, the fully closed position as -100%, and the center position as 0. On this basis, the displacement of the valve core is positioned in the form of percentage, and θ 开 >0>θ 关 .

3. The method for determining a twitching fault according to claim 2, characterized in that: The detection of the relationship between the valve core position and the threshold value in step 2 is to simultaneously detect the relationship between the valve core displacement and the open and closed position thresholds within one detection cycle.

4. The method for determining a twitching fault according to claim 3, characterized in that: The specific process of detecting the relationship between the valve core position and the open position threshold is as follows: If the valve core displacement value is greater than the set value θ 开 , set a Boolean variable A to 1, which is less than θ 开 When A returns to 0, and the valve core displacement is greater than θ 开 Once, the integer variable B is incremented by 1.

5. The method for determining a twitching fault according to claim 4, characterized in that: The specific process of detecting the relationship between the valve core position and the closed position threshold is as follows: If the valve core displacement value is less than the set value θ 关 , set a Boolean variable C to 1, which is greater than θ 关 When C returns to 0, and the valve core displacement is less than θ 关 Once, the integer variable D is incremented by 1.

6. The method for determining a twitching fault according to claim 5, characterized in that: The adjacent state described in step 3 refers to that the time interval between two twitches is less than half a cycle.

7. The method for determining a twitching fault according to claim 6, characterized in that: The specific method of judging whether the detection result of step 2 meets the twitching fault condition in step 4 is to set the twitching number threshold value γ. Within one detection cycle, if the cumulative value of B and D is greater than γ, and the absolute value of the deviation of BD is less than 3, then the detection result of step 2 meets the twitching fault condition; if the twitching fault condition is not met within one detection cycle, wait for the timer to refresh.

8. The method for determining a twitching fault according to claim 7, characterized in that: The specific method of determining whether the detection result of step 3 satisfies the twitching fault condition in step 4 is to set the empirical frequency range and the frequency deviation threshold α. Within a detection cycle, if the twitching frequency is within the empirical frequency range and the absolute value of the adjacent frequency deviation is less than α, then the detection result of step 3 satisfies the twitching fault condition; if the twitching fault condition is not met within a detection cycle, then wait for the timer to refresh.

9. The method for determining a twitching fault according to claim 8, characterized in that: After step 4 outputs the main pressure regulating valve twitching fault signal to the main pressure regulating valve control end, the turbine speed governor corresponding to the main pressure regulating valve switches control, starts the backup equipment, and cuts off the fault point.

10. A judgment system for FC main pressure distribution valve main distribution twitching failure, characterized in that: include: Preparation module, used to connect the main pressure distribution valve spool displacement signal to the detection device and define the spool opening position threshold θ 开 , Close position threshold θ 关 , set the detection cycle and start the timer; The twitch frequency detection module is used to detect the relationship between the valve core position and the threshold value within a detection cycle, and record the total number of times the valve core reaches the open and closed position thresholds; A twitching frequency detection module is used to draw a displacement-time curve of the valve core within a detection cycle, and detect the twitching frequency and the deviation of adjacent twitching frequencies; The fault judgment module is used to judge whether the twitching fault conditions are met based on the detection results obtained in the twitching number detection module and the twitching frequency detection module. If the detection results obtained by the aforementioned modules are all met, the main and auxiliary twitching fault signal is output; if not, the timer is reset and the detection is restarted.

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