A control rod drive mechanism online monitoring method

Abstract

The present invention belongs to the control rod technology of nuclear power plants, and specifically relates to an online monitoring method for a rod driving mechanism, which collects the current value in the control rod driving mechanism loop and converts it into a voltage signal, obtains a voltage signal real-time display curve, filters it, and then determines whether there are moving rod feature points, extracts the moving rod feature points that exist after determination, obtains a moving rod curve, and performs online curve monitoring through pit identification and out-of-tolerance comparison. An alarm is given to the driving mechanism that deviates from the preset value, and a judgment is made in advance to avoid rod drop due to module performance degradation. It is capable of monitoring 103 control rod driving mechanisms at the same time and processing high-concurrency data; the accuracy of judgment is improved by reducing the deviation of the characteristic value of the power supply action curve of the control rod driving mechanism and identifying the characteristic curve of the "pit".

Description

Technical Field

[0001] The invention belongs to the control rod technology of nuclear power plants, and in particular relates to an online monitoring method for a rod making driving mechanism. Background Art

[0002] Control rods are an important means of controlling reactivity in nuclear power plants. Their operation is related to the stable power generation of nuclear power plants. In order to analyze the operating trends of control rods and summarize their fault conditions, it is necessary to develop and implement monitoring functions.

[0003] The control rods of a nuclear power plant are controlled by the control rod drive mechanism, and move in the core with the drive rod of the control rod drive mechanism. The power supply of the control rod drive mechanism is realized by energizing the three electromagnet coils installed on it, and its movement is achieved by providing a timing current to the electromagnet coils, and the three coils are energized and de-energized in order to realize the functions of holding, lifting and inserting the control rods, thereby realizing the regulation of reactor power. The power supply of the control rod drive mechanism comes from the 0.4kV reliable busbar in the nuclear power plant area, and is realized through the control rod power supply cabinet in the rod control rod position system. Each cabinet is equipped with three AC power supply modules, and one AC power supply module corresponds to the three electromagnet coils of a bundle of control rods.

[0004] The control rod only takes 1 second to move one step. The three electromagnet coils of the drive mechanism have to coordinate multiple times within 1 second. If there is an abnormal power supply to one coil, it will inevitably affect the normal operation of the control rod, and even risk the control rod falling. Therefore, it is necessary to add online monitoring equipment at the power supply end of the control rod to monitor the current of the control rod drive mechanism online. Summary of the invention

[0005] The object of the present invention is to provide an online monitoring method for a control rod drive mechanism, which can automatically monitor the control rod drive mechanism in a pressurized water reactor nuclear power plant online to avoid rod drop due to module performance degradation.

[0006] The technical solution of the present invention is as follows:

[0007] A control rod drive mechanism online monitoring method comprises the following steps:

[0008] 1) Collect the current value in the control rod drive mechanism circuit and convert the current signal into a voltage signal;

[0009] 2) Draw a real-time display curve of the voltage signal and convert it into a real-time display curve of the current signal;

[0010] 3) Read the current signal in real time;

[0011] 4) Signal filtering;

[0012] 5) Determine whether there are moving rod feature points, which include rod lifting feature points and rod inserting feature points;

[0013] If there are moving rod feature points, that is, there are rod lifting feature points or rod inserting feature points, execute step 6);

[0014] Otherwise, execute step 3);

[0015] 6) Extract the existing moving rod feature points after determination to obtain a moving rod curve;

[0016] 7) Perform concave pit recognition and out-of-tolerance comparison on the moving rod curve;

[0017] If there is a concave pit, execute step 3);

[0018] If there is no concave pit, execute step 8);

[0019] If there is no out-of-tolerance, execute step 4);

[0020] If there is out-of-tolerance, execute step 8).

[0021] The judgment method of the rod lifting feature points in step 5) is specifically as follows:

[0022] According to the real-time display curve of the current signal, set a, b, and c as three time points for feature judgment;

[0023] If at a certain time point, the corresponding lifting coil value PM, holding coil value BM, and transfer coil value FM at this point simultaneously satisfy: pm1 < PM < pm2, bm1 < BM < bm2, fm1 < FM < fm2, then this point is considered as the first judgment time point, point a; if the above three conditions are not satisfied, then there is no point a and no rod lifting feature point;

[0024] After determining the existence of point a, judge the respective characteristic values corresponding to the second time point b after point a: If the lifting coil value PM(b), holding coil value BM(b), and transfer coil value FM(b) at point b satisfy pm3 < PM(b) < pm4, bm3 < BM(b) < bm4, fm3 < FM(b) < fm4, then judge the lifting coil value PM(c), holding coil value BM(c), and transfer coil value FM(c) at point c after point b; if not satisfied, then there is no rod lifting feature point;

[0025] If the respective corresponding values at point c satisfy: pm5 < PM(c) < pm6, bm5 < BM(c) < bm6, fm5 < FM(c) < fm6, then it is determined that points a, b, and c are rod lifting feature points and the rod lifting action occurs.

[0026] The time interval between points a, b, and c is 0.3 - 0.6 s.

[0027] pm1 is the lower limit of the lifting coil value PM corresponding to time point a, and its value is -0.2A;

[0028] pm2 is the upper limit of the lifting coil value PM corresponding to time point a, and its value is 0.2A;

[0029] bm1 is the lower limit of the holding coil value BM corresponding to time point a, and its value is 1.0A;

[0030] bm2 is the upper limit of the holding coil value BM corresponding to time point a, and its value is 2.0A;

[0031] fm1 is the lower limit of the loop value FM corresponding to time point a, and its value is 5.5A;

[0032] fm2 is the upper limit of the loop value FM corresponding to time point a, and its value is 6.5A;

[0033] pm3 is the lower limit of the lifting coil value PM(b) corresponding to time point b, and its value is 13.5A;

[0034] pm4 is the upper limit of the lifting coil value PM(b) corresponding to time point b, and its value is 14.5A;

[0035] bm3 is the lower limit of the holding coil value BM(b) corresponding to time point b, and its value is 12.5A;

[0036] bm4 is the upper limit of the holding coil value BM(b) corresponding to time point b, and its value is 13.5A;

[0037] fm3 is the lower limit of the loop value FM(b) corresponding to time point b, and its value is -0.2A;

[0038] fm4 is the upper limit of the loop value FM(b) corresponding to time point b, and its value is 0.2A;

[0039] pm5 is the lower limit of the lifting coil value PM(c) corresponding to time point c, and its value is 5.0A;

[0040] pm6 is the upper limit of the lifting coil value PM(c) corresponding to time point c, and its value is 6.0A;

[0041] bm5 is the lower limit of the holding coil value BM(c) corresponding to time point c, and its value is -0.2A;

[0042] bm6 is the upper limit of the holding coil value BM(c) corresponding to time point c, and its value is 0.2A;

[0043] fm5 is the lower limit of the transfer coil value FM(c) corresponding to time point c, with a value of 8.5 A;

[0044] fm6 is the upper limit of the transfer coil value FM(c) corresponding to time point c, with a value of 9.5 A.

[0045] The determination method of the plunger feature points in step 5) is specifically as follows:

[0046] According to the real-time display curve of the voltage signal, set d, e, and f as three time points for feature determination;

[0047] If at a certain time point, the corresponding lift coil value PM, hold coil value BM, and transfer coil value FM at this point simultaneously satisfy: pm7 < PM(d) < pm8, bm7 < BM(d) < bm8, fm7 < FM(d) < fm8, then this point is considered the first determination time point d; if the above three conditions are not met, there is no point d, and there is no plunger feature point;

[0048] After determining that there is a point d, judge the value of point e after point d: if the lift coil value PM(e), hold coil value BM(e), and transfer coil value FM(e) at point e satisfy pm9 < PM(e) < pm10, bm9 < BM(e) < bm10, fm9 < FM(e) < fm10, then judge the lift coil value PM(f), hold coil value BM(f), and transfer coil value FM(f) at point f after point e; if not, there is no plunger feature point;

[0049] If it satisfies: pm11 < PM(f) < pm12, bm11 < BM(f) < bm12, fm11 < FM(f) < fm12, then it is determined that points d, e, and f are plunger feature points, and it is determined that the plunger action occurs.

[0050] The time interval between points d, e, and f is 0.3 - 0.6 s.

[0051] pm7 is the lower limit of the lift coil value PM(d) corresponding to time point d, with a value of 6.0 A;

[0052] pm8 is the upper limit of the lift coil value PM(d) corresponding to time point d, with a value of 8.0 A;

[0053] bm7 is the lower limit of the hold coil value BM(d) corresponding to time point d, with a value of 1.0 A;

[0054] bm8 is the upper limit of the hold coil value BM(d) corresponding to time point d, with a value of 3.0 A;

[0055] fm7 is the lower limit of the loop value FM(d) corresponding to the time point d, and its value is 5.5A;

[0056] fm8 is the upper limit of the loop value FM(d) corresponding to the time point d, and its value is 6.5A;

[0057] pm9 is the lower limit of the lifting coil value PM(e) corresponding to time point e, and its value is 12.5A;

[0058] pm10 is the upper limit of the lifting coil value PM(e) corresponding to time point e, and its value is 13.5A;

[0059] bm9 is the lower limit of the holding coil value BM(e) corresponding to time point e, and its value is 7.5A;

[0060] bm10 is the upper limit of the holding coil value BM(e) corresponding to time point e, and its value is 8.5A;

[0061] fm9 is the lower limit of the loop value FM(e) corresponding to the time point e, and its value is -0.5A;

[0062] fm10 is the upper limit of the loop value FM(e) corresponding to the time point e, and its value is 0.5A;

[0063] pm11 is the lower limit of the lifting coil value PM(f) corresponding to time point f, and its value is -0.5A;

[0064] pm12 is the upper limit of the lifting coil value PM(f) corresponding to time point f, and its value is 0.5A;

[0065] bm11 is the lower limit of the holding coil value BM(f) corresponding to time point f, and its value is 7.5A;

[0066] bm12 is the upper limit of the holding coil value BM(e) corresponding to time point f, and its value is 8.5A;

[0067] fm11 is the lower limit of the loop value FM(f) corresponding to the time point f, and its value is -0.5A;

[0068] fm12 is the upper limit of the loop value FM(f) corresponding to the time point f, and its value is 0.5A.

[0069] The determination method for identifying the pits on the moving rod curve in step 7) is:

[0070] Determine a pit feature point recognition decision diagram, where the horizontal axis is time and the vertical axis is the coil current value;

[0071] Select point A corresponding to the minimum current value within the time period T, read the current value data of the time period Δt before point A, and the current value data of the time period Δt after point A, select point D with the maximum current value on the curve from point B to point A, point E with the maximum current value on the curve from point A to point C, and the starting point F and ending point G of the data segment with a time length of T;

[0072] Determine the relationship between point A and points F and G, specifically including:

[0073] If point A and point F coincide, then it is necessary to continue to determine the relationship between point A and point D: (1) If the value of point D is less than or equal to the value of point A, it is determined that there is no pit; (2) If the value of point D is greater than the value of point A, it is necessary to continue to determine the relationship between the numerical difference between points D and A and the numerical difference between points E and A: If the difference is greater than δ, it is determined that a pit exists, otherwise the pit does not exist;

[0074] If point A and point G coincide, then it is necessary to compare the values ​​of point A and point E: (1) If the value of point E is less than or equal to the value of point A, it is determined that the pit does not exist; (2) If the value of point E is greater than the value of point A, it is necessary to continue to determine the relationship between the value difference between points D and A and the value difference between points E and A: If the difference is greater than δ, it is determined that the pit exists, otherwise the pit does not exist;

[0075] When point A does not coincide with points F and G, it is necessary to determine the numerical difference between points D and A and the numerical difference between points E and A: if the differences are both greater than δ, it is determined that the pit exists; otherwise, the pit does not exist.

[0076] The T value range is 300-500ms, and the δ value range is 0.2-0.5.

[0077] The method for determining the deviation of the moving rod curve in step 7) is as follows:

[0078] Determine the standard curves for lifting and inserting rods according to the driving mechanism equipment;

[0079] Process the standard curve: multiply the ordinate value of the standard curve (i.e., coil current value) by 1.05 to form the upper range curve X1, and multiply the value of the standard curve by 0.95 to form the lower range curve X2; curves X1 and X2 form a two-dimensional array with a time interval of h, which are recorded as XA = {(a0, t0), (a1, t1) ... (aNA, tNA), XB = {(b0, t0), (b1, t1) ... (bNB, tNB)}; the moving rod curve extracted in step 6) forms an array XC = {(c0, t0), (c1, t1) ... (cNC, tNC)} with a time interval of h; NA, NB, NC are the number of points in each array, and the same value is 100-2000; a, b, c in the array represent the ordinate on each curve, i.e., the coil current value, t represents the abscissa, i.e., the time point, and the suffix number represents the data sequence number of the interval;

[0080] Compare each two-dimensional array XC with XA and XB according to the ordinates corresponding to the interval time points: if the array value of XC, that is, the ordinate value, exceeds the range limited by the ordinate value of XA and the ordinate value of XB, it is considered that an out-of-tolerance exists; otherwise, the curve is normal.

[0081] In the step 5), high-frequency ripples above 5 Hz are filtered out.

[0082] The significant effects of the present invention are as follows: it will realize the online monitoring of the current value of the rod position and rod control system, automatically extract the moving rod curve and store and analyze it, give an alarm to the drive mechanism that deviates from the preset value, make a judgment in advance, and avoid the rod falling due to the degradation of module performance. It can monitor 103 control rod drive mechanisms at the same time and process high-concurrency data; by reducing the deviation of the characteristic value of the power supply action curve of the control rod drive mechanism and identifying the characteristic curve of the "pit", the accuracy of the judgment is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 A flow chart for implementing an online detection method for a control rod drive mechanism;

[0084] Figure 2 To provide a rod curve feature point recognition decision diagram;

[0085] Figure 3 It is the identification and judgment diagram of the characteristic points of the plug-in curve;

[0086] Figure 4 It is a determination map for pit feature point recognition;

[0087] Figure 5 This is the timing diagram of the standard curve for lifting and inserting the rod; DETAILED DESCRIPTION

[0088] The present invention will be further described below through the accompanying drawings and specific implementation methods.

[0089] like Figure 1 As shown, the implementation process of this method is described in steps.

[0090] Step 1: Continuous signal acquisition

[0091] The current value in the control rod drive mechanism circuit is collected by the Hall sensor, and the current signal is converted into a voltage signal.

[0092] In this embodiment, the Hall sensor outputs a 4-20A current signal, and the 4-20A signal is converted into a 1-5V voltage.

[0093] Step 2: Data cache and update

[0094] The collected and converted voltage signals are stored as data and updated in real time according to the collection time;

[0095] In this step, curves can be drawn based on signal data and time tags to obtain real-time display curves of voltage signals. The collected signals can also be recorded and recorded in a historical database for subsequent processing and analysis, and to prepare for subsequent data queries.

[0096] The above-mentioned voltage signal is converted into a current signal, which is the vertical coordinate in the subsequent feature point determination diagram, representing the dynamic rod information corresponding to each time (1-5V voltage signal corresponds to 0-50A current signal), which is the real-time display curve of the current signal required in the subsequent steps.

[0097] Step 3: Read the cache signal

[0098] Retrieve the above cached signal in real time for calculation in subsequent steps

[0099] Step 4: Signal filtering

[0100] Filter the waveform and use wavelet analysis method to filter out high-frequency ripples;

[0101] In this embodiment, high-frequency ripples above 5 Hz are filtered out.

[0102] Step 5: Determine whether there are moving rod feature points

[0103] The moving rod feature points are the feature points of lifting and inserting the rod

[0104] like Figure 2 As shown in the figure, the judgment criteria for the lifting feature point are:

[0105] The curve is displayed in real time according to the current signal obtained above, where abc are three time points for feature judgment;

[0106] If at a certain point in time, the corresponding pickup coil value PM, holding coil value BM, and transfer coil value FM at this point simultaneously satisfy: pm1 < PM < pm2, bm1 < BM < bm2, fm1 < FM < fm2, then this point is considered the first judgment time point, point a; if the above three conditions are not met, then there is no point a, and there is no rod-lifting characteristic point either.

[0107] pm1 is the lower limit of the pickup coil value PM corresponding to time point a, and its value is -0.2 A.

[0108] pm2 is the upper limit of the pickup coil value PM corresponding to time point a, and its value is 0.2 A.

[0109] bm1 is the lower limit of the holding coil value BM corresponding to time point a, and its value is 1.0 A.

[0110] bm2 is the upper limit of the holding coil value BM corresponding to time point a, and its value is 2.0 A.

[0111] fm1 is the lower limit of the transfer coil value FM corresponding to time point a, and its value is 5.5 A.

[0112] fm2 is the upper limit of the transfer coil value FM corresponding to time point a, and its value is 6.5 A.

[0113] After determining the existence of point a, judge the respective characteristic values corresponding to the second time point b, 0.4 s after point a: If the pickup coil value PM(b), holding coil value BM(b), and transfer coil value FM(b) at point b satisfy pm3 < PM(b) < pm4, bm3 < BM(b) < bm4, fm3 < FM(b) < fm4, then judge the pickup coil value PM(c), holding coil value BM(c), and transfer coil value FM(c) at point c, 0.4 s after point b; if not, then there is no rod-lifting characteristic point.

[0114] Among them

[0115] pm3 is the lower limit of the pickup coil value PM(b) corresponding to time point b, and its value is 13.5 A.

[0116] pm4 is the upper limit of the pickup coil value PM(b) corresponding to time point b, and its value is 14.5 A.

[0117] bm3 is the lower limit of the holding coil value BM(b) corresponding to time point b, and its value is 12.5 A.

[0118] bm4 is the upper limit of the holding coil value BM(b) corresponding to time point b, and its value is 13.5 A.

[0119] fm3 is the lower limit of the transfer coil value FM(b) corresponding to time point b, with a value of -0.2 A;

[0120] fm4 is the upper limit of the transfer coil value FM(b) corresponding to time point b, with a value of 0.2 A;

[0121] If the corresponding values at point c satisfy: pm5 < PM(c) < pm6, bm5 < BM(c) < bm6, fm5 < FM(c) < fm6, then it is determined that points a, b, and c are the rod-lifting characteristic points, and the rod-lifting action occurs.

[0122] Among them

[0123] pm5 is the lower limit of the lifting coil value PM(c) corresponding to time point c, with a value of 5.0 A;

[0124] pm6 is the upper limit of the lifting coil value PM(c) corresponding to time point c, with a value of 6.0 A;

[0125] bm5 is the lower limit of the holding coil value BM(c) corresponding to time point c, with a value of -0.2 A;

[0126] bm6 is the upper limit of the holding coil value BM(c) corresponding to time point c, with a value of 0.2 A;

[0127] fm5 is the lower limit of the transfer coil value FM(c) corresponding to time point c, with a value of 8.5 A;

[0128] fm6 is the upper limit of the transfer coil value FM(c) corresponding to time point c, with a value of 9.5 A;

[0129] As Figure 3 shown, the judgment criterion for the rod-inserting characteristic points is:

[0130] According to the real-time display curve of the voltage signal obtained above, d, e, and f are three time points for feature judgment;

[0131] If at a certain time point, there exist the lifting coil value PM, the holding coil value BM, and the transfer coil value FM corresponding to this point that simultaneously satisfy: pm7 < PM(d) < pm8, bm7 < BM(d) < bm8, fm7 < FM(d) < fm8, then this point is considered as the first judgment time point d; if the above three conditions are not satisfied, then there is no d point, and there is no rod-inserting characteristic point either;

[0132] pm7 is the lower limit of the lifting coil value PM(d) corresponding to time point d, with a value of 6.0 A;

[0133] pm8 is the upper limit of the lifting coil value PM(d) corresponding to time point d, with a value of 8.0 A;

[0134] bm7 is the lower limit of the holding coil value BM(d) corresponding to time point d, with a value of 1.0 A;

[0135] bm8 is the upper limit of the holding coil value BM(d) corresponding to time point d, with a value of 3.0 A;

[0136] fm7 is the lower limit of the transfer coil value FM(d) corresponding to time point d, with a value of 5.5 A;

[0137] fm8 is the upper limit of the transfer coil value FM(d) corresponding to time point d, with a value of 6.5 A;

[0138] After determining the existence of point d, the value of point e 0.4 s after point d is judged: If the lifting coil value PM(e), holding coil value BM(e), and transfer coil value FM(e) at point e satisfy pm9 < PM(e) < pm10, bm9 < BM(e) < bm10, and fm9 < FM(e) < fm10, then the lifting coil value PM(f), holding coil value BM(f), and transfer coil value FM(f) at point f 0.4 s after point e are judged; if not satisfied, there is no plunger feature point;

[0139] pm9 is the lower limit of the lifting coil value PM(e) corresponding to time point e, with a value of 12.5 A;

[0140] pm10 is the upper limit of the lifting coil value PM(e) corresponding to time point e, with a value of 13.5 A;

[0141] bm9 is the lower limit of the holding coil value BM(e) corresponding to time point e, with a value of 7.5 A;

[0142] bm10 is the upper limit of the holding coil value BM(e) corresponding to time point e, with a value of 8.5 A;

[0143] fm9 is the lower limit of the transfer coil value FM(e) corresponding to time point e, with a value of -0.5 A;

[0144] fm10 is the upper limit of the transfer coil value FM(e) corresponding to time point e, with a value of 0.5 A;

[0145] If satisfied: pm11 < PM(f) < pm12, bm11 < BM(f) < bm12, fm11 < FM(f) < fm12, then it is determined that points d, e, and f are plunger feature points, and it is determined that the plunger action occurs.

[0146] pm11 is the lower limit of the lifting coil value PM(f) corresponding to time point f, with a value of -0.5 A;

[0147] pm12 is the upper limit of the lifting coil value PM(f) corresponding to time point f, and its value is 0.5A;

[0148] bm11 is the lower limit of the holding coil value BM(f) corresponding to time point f, and its value is 7.5A;

[0149] bm12 is the upper limit of the holding coil value BM(e) corresponding to time point f, and its value is 8.5A;

[0150] fm11 is the lower limit of the loop value FM(f) corresponding to the time point f, and its value is -0.5A;

[0151] fm12 is the upper limit of the loop value FM(f) corresponding to the time point f, and its value is 0.5A;

[0152] If there are feature points for lifting or inserting the rod, execute step 6;

[0153] Otherwise, go to step 3;

[0154] Step 6: Extract the moving rod curve

[0155] The characteristic points of the rod lifting or rod insertion that exist after the judgment are extracted to obtain the rod moving curve (the horizontal axis of the curve is time, and the vertical axis is the coil current value) as the rod moving record.

[0156] Step 7: Identify the pits on the moving rod curve and compare the deviations

[0157] When performing pit recognition:

[0158] The determination method is:

[0159] like Figure 4 As shown, the pit feature point recognition and determination diagram has a horizontal axis representing time and a vertical axis representing coil current value, which can indicate that in the actual moving rod curve, a characteristic curve (i.e., a pit) pattern should appear within a certain period of time.

[0160] The pit identification is to determine the minimum value and the value in the time period before and after it in a specific curve area (taking the pit feature point identification determination diagram as an example). When the difference between the before and after exceeds the set range, it is determined that the pit exists, otherwise it is determined that the pit does not exist.

[0161] a) Determine the data segment of time length T and its features Judgment Point

[0162] Determine a data segment of time length T, generally T is in the range of 300-500ms, and in this embodiment, it is 340ms;

[0163] Select point A corresponding to the minimum current value within the time period T, read the current value data of the time period Δt before point A (the curve part from point B to point A), and the current value data of the time period Δt after point A (curve point A to point C), select point D with the maximum current value on the curve from point B to point A, point E with the maximum current value on the curve from point A to point C, the starting point F and the ending point G of this data segment with a time length of T.

[0164] The value range of Δt is 35-50ms, and the value in this embodiment is 40ms;

[0165] b) First determine the relationship between point A and points F and G

[0166] If point A and point F coincide, you need to continue to determine the relationship between point A and point D:

[0167] (1) If the value of point D is less than or equal to the value of point A, it is determined that there is no pit;

[0168] (2) If the value of point D is greater than the value of point A, it is necessary to continue to determine the relationship between the numerical difference between points D and A and the numerical difference between points E and A: if the difference is greater than δ (δ is a positive number), it is determined that the pit exists, otherwise the pit does not exist. Generally, the value range of δ is 0.2-0.5, and the value in this embodiment is 0.3;

[0169] If point A coincides with point G, then you need to compare the values ​​of point A with point E:

[0170] (1) If the value of point E is less than or equal to the value of point A, it is determined that the pit does not exist;

[0171] (2) If the value of point E is greater than the value of point A, it is necessary to continue to determine the relationship between the numerical difference between points D and A and the numerical difference between points E and A: if the differences are all greater than δ, it is determined that the pit exists; otherwise, the pit does not exist.

[0172] When point A does not coincide with points F and G, it is necessary to determine the numerical difference between points D and A and the numerical difference between points E and A: if the differences are both greater than δ, it is determined that the pit exists; otherwise, the pit does not exist.

[0173] If there is a pit, execute step 3;

[0174] If there is no pit, proceed to step 8;

[0175] When performing out-of-tolerance comparison:

[0176] First determine whether it is out of tolerance

[0177] The specific method of determination is:

[0178] like Figure 5The standard curve of rod lifting and rod insertion is shown (this curve is provided by the equipment related to the drive mechanism and is included with the equipment product. The figure shows the standard timing curve of the control rod drive mechanism of the Tianwan Nuclear Power Plant).

[0179] First, the standard curve is processed: the ordinate value of the standard curve (i.e., the coil current value) is multiplied by 1.05 to form the upper range curve X1, and the value of the standard curve is multiplied by 0.95 to form the lower range curve X2;

[0180] The curve X1 is formed into a two-dimensional array XA = {(a0, t0), (a1, t1) ... (aNA, tNA)} at a time interval of 1 ms; the curve X2 is formed into a two-dimensional array XB = {(b0, t0), (b1, t1) ... (bNB, tNB)} at a time interval of 1 ms;

[0181] Where a represents the ordinate of each point on curve X1, b represents the ordinate of each point on curve X2, t represents the abscissa (time point), the subsequent digital numbers represent the data sequence number of the interval, NA is the number of points on curve X1; NB is the number of points on curve X2;

[0182] The moving rod curve extracted in step 6 is formed into an array XC = {(c0, t0), (c1, t1) ... (cNC, tNC)} at a time interval of 1 ms; c represents the ordinate of each point in the moving rod curve (coil current value), t represents the abscissa (time point), the subsequent digital labels represent the data sequence number of the interval, and NC is the number of points taken in the moving rod curve;

[0183] In this embodiment, the values ​​of NA, NB, and NC are the same, ranging from 100 to 2000, and the value in this embodiment is 999.

[0184] The arrays of XC, XA and XB are compared one by one according to the time digital labels: if the array value of XC exceeds the range of XA and XB, it is considered that an error exists; if the array value of XC is between XA and XB, the data is normal.

[0185] For example, if the value of c1 is in [a1,b1], then the point is normal;

[0186] If it is not within the interval, then the point is an out-of-tolerance point. As long as there is a point that is an out-of-tolerance point, the moving bar curve out-of-tolerance exists.

[0187] If the moving rod curve does not exceed the tolerance, proceed to step 4;

[0188] If the moving rod curve is out of tolerance, execute step 8;

[0189] Step 8: Generate events and alarm reminders.

Claims

1. A control rod drive mechanism online monitoring method, characterized in that: It includes the following steps: 1) Collect the current value in the control rod drive mechanism loop and convert the current signal into a voltage signal; 2) Draw a real-time display curve of the voltage signal and convert it into a real-time display curve of the current signal; 3) Read the current signal in real time; 4) Signal filtering; 5) Determine whether there are moving rod characteristic points, including rod lifting characteristic points and rod inserting characteristic points; If there are moving rod characteristic points, that is, there are rod lifting characteristic points or rod inserting characteristic points, execute step 6); Otherwise, execute step 3); 6) Extract the existing moving rod characteristic points after determination to obtain a moving rod curve; 7) Identify the pits on the moving rod curve and compare with the tolerance; If there are pits, execute step 3); If there are no pits, execute step 8); If there is no out-of-tolerance, execute step 4); If there is out-of-tolerance, execute step 8).

2. The online monitoring method for a control rod drive mechanism according to claim 1, characterized in that: The specific method for judging the rod lifting characteristic points in step 5) is as follows: According to the real-time display curve of the current signal, set a, b, and c as three time points for feature judgment; If at a certain time point, the corresponding lifting coil value PM, holding coil value BM, and transfer coil value FM at this point simultaneously satisfy: pm1 < PM < pm2, bm1 < BM < bm2, fm1 < FM < fm2, then this point is considered as the first judgment time point, point a; if the above three conditions are not met, then there is no point a and no rod lifting characteristic points; After determining the existence of point a, judge the respective characteristic values corresponding to the second time point b after point a: if the lifting coil value PM(b), holding coil value BM(b), and transfer coil value FM(b) at point b satisfy pm3 < PM(b) < pm4, bm3 < BM(b) < bm4, fm3 < FM(b) < fm4, then judge the lifting coil value PM(c), holding coil value BM(c), and transfer coil value FM(c) at point c after point b; if not satisfied, then there are no rod lifting characteristic points; If the respective corresponding values at point c satisfy: pm5 < PM(c) < pm6, bm5 < BM(c) < bm6, fm5 < FM(c) < fm6, then it is determined that points a, b, and c are rod lifting characteristic points and the rod lifting action occurs.

3. The method for online monitoring of a control rod drive mechanism according to claim 2, characterized in that: The time interval between points a, b, and c is 0.3 - 0.6 s.

4. The on-line monitoring method of a control rod drive mechanism according to claim 2, characterized in that: pm1 is the lower limit of the lifting coil value PM corresponding to time point a, and its value is -0.2 A; pm2 is the upper limit of the lifting coil value PM corresponding to time point a, and its value is 0.2 A; bm1 is the lower limit of the holding coil value BM corresponding to time point a, and its value is 1.0 A; bm2 is the upper limit of the holding coil value BM corresponding to time point a, and its value is 2.0 A; fm1 is the lower limit of the transfer coil value FM corresponding to time point a, and its value is 5.5 A; fm2 is the upper limit of the transfer coil value FM corresponding to time point a, and its value is 6.5 A; pm3 is the lower limit of the lifting coil value PM(b) corresponding to time point b, and its value is 13.5 A; pm4 is the upper limit of the lifting coil value PM(b) corresponding to time point b, and its value is 14.5 A; bm3 is the lower limit of the holding coil value BM(b) corresponding to time point b, with a value of 12.5 A; bm4 is the upper limit of the holding coil value BM(b) corresponding to time point b, with a value of 13.5 A; fm3 is the lower limit of the transfer coil value FM(b) corresponding to time point b, with a value of -0.2 A; fm4 is the upper limit of the transfer coil value FM(b) corresponding to time point b, with a value of 0.2 A; pm5 is the lower limit of the lifting coil value PM(c) corresponding to time point c, with a value of 5.0 A; pm6 is the upper limit of the lifting coil value PM(c) corresponding to time point c, with a value of 6.0 A; bm5 is the lower limit of the holding coil value BM(c) corresponding to time point c, with a value of -0.2 A; bm6 is the upper limit of the holding coil value BM(c) corresponding to time point c, with a value of 0.2 A; fm5 is the lower limit of the transfer coil value FM(c) corresponding to time point c, with a value of 8.5 A; fm6 is the upper limit of the transfer coil value FM(c) corresponding to time point c, with a value of 9.5 A.

5. The method for online monitoring of a control rod drive mechanism according to claim 1, characterized in that: The judgment method of the plunger feature points in step 5) is specifically as follows: According to the real-time display curve of the voltage signal, set d, e, and f as three time points for feature judgment; If at a certain time point, the corresponding lifting coil value PM, holding coil value BM, and transfer coil value FM at this point simultaneously satisfy: pm7 < PM(d) < pm8, bm7 < BM(d) < bm8, fm7 < FM(d) < fm8, then this point is considered as the first judgment time point d; if the above three conditions are not met, then there is no d point, and there is no plunger feature point; After determining the existence of point d, judge the value of point e after point d: If the lifting coil value PM(e), holding coil value BM(e), and transfer coil value FM(e) at point e satisfy pm9 < PM(e) < pm10, bm9 < BM(e) < bm10, fm9 < FM(e) < fm10, then judge the lifting coil value PM(f), holding coil value BM(f), and transfer coil value FM(f) at point f after point e; if not, there is no plunger feature point; If it satisfies: pm11 < PM(f) < pm12, bm11 < BM(f) < bm12, fm11 < FM(f) < fm12, then determine that points d, e, and f are plunger feature points, and determine that the plunger action occurs.

6. The method for online monitoring of a control rod drive mechanism according to claim 5, characterized in that: The time interval between points d, e, and f is 0.3 - 0.6 s.

7. A method for on-line monitoring of a control rod drive mechanism according to claim 5, characterized in that: pm7 is the lower limit of the lifting coil value PM(d) corresponding to time point d, with a value of 6.0 A; pm8 is the upper limit of the lifting coil value PM(d) corresponding to time point d, with a value of 8.0 A; bm7 is the lower limit of the holding coil value BM(d) corresponding to time point d, with a value of 1.0 A; bm8 is the upper limit of the holding coil value BM(d) corresponding to time point d, with a value of 3.0 A; fm7 is the lower limit of the loop value FM(d) corresponding to the time point d, and its value is 5.5A; fm8 is the upper limit of the loop value FM(d) corresponding to the time point d, and its value is 6.5A; pm9 is the lower limit of the lifting coil value PM(e) corresponding to time point e, and its value is 12.5A; pm10 is the upper limit of the lifting coil value PM(e) corresponding to time point e, and its value is 13.5A; bm9 is the lower limit of the holding coil value BM(e) corresponding to time point e, and its value is 7.5A; bm10 is the upper limit of the holding coil value BM(e) corresponding to time point e, and its value is 8.5A; fm9 is the lower limit of the loop value FM(e) corresponding to the time point e, and its value is -0.5A; fm10 is the upper limit of the loop value FM(e) corresponding to the time point e, and its value is 0.5A; pm11 is the lower limit of the lifting coil value PM(f) corresponding to time point f, and its value is -0.5A; pm12 is the upper limit of the lifting coil value PM(f) corresponding to time point f, and its value is 0.5A; bm11 is the lower limit of the holding coil value BM(f) corresponding to time point f, and its value is 7.5A; bm12 is the upper limit of the holding coil value BM(e) corresponding to time point f, and its value is 8.5A; fm11 is the lower limit of the loop value FM(f) corresponding to the time point f, and its value is -0.5A; fm12 is the upper limit of the loop value FM(f) corresponding to the time point f, and its value is 0.5A.

8. The method for online monitoring of a control rod drive mechanism according to claim 1, characterized in that: The determination method for identifying the pits on the moving rod curve in step 7) is: Determine a pit feature point recognition decision diagram, where the horizontal axis is time and the vertical axis is the coil current value; Select point A corresponding to the minimum current value within the time period T, read the current value data of the time period Δt before point A, and the current value data of the time period Δt after point A, select point D with the maximum current value on the curve from point B to point A, point E with the maximum current value on the curve from point A to point C, and the starting point F and ending point G of the data segment with a time length of T; Determine the relationship between point A and points F and G, specifically including: If point A and point F coincide, it is necessary to continue to determine the relationship between point A and point D: (1) If the value of point D is less than or equal to the value of point A, it is determined that there is no pit; (2) If the value of point D is greater than the value of point A, it is necessary to continue to determine the relationship between the numerical difference between points D and A and the numerical difference between points E and A: If the difference is greater than δ, it is determined that a pit exists, otherwise the pit does not exist; If point A and point G coincide, then it is necessary to compare the values ​​of point A and point E: (1) If the value of point E is less than or equal to the value of point A, it is determined that the pit does not exist; (2) If the value of point E is greater than the value of point A, it is necessary to continue to determine the relationship between the value difference between points D and A and the value difference between points E and A: If the difference is greater than δ, it is determined that the pit exists, otherwise the pit does not exist; When point A does not coincide with points F and G, it is necessary to determine the numerical difference between points D and A and the numerical difference between points E and A: if the differences are both greater than δ, it is determined that the pit exists; otherwise, the pit does not exist.

9. The method for online monitoring of a control rod drive mechanism according to claim 8, characterized in that: The T value range is 300-500ms, and the δ value range is 0.2-0.

5.

10. The online monitoring method for a control rod drive mechanism according to claim 1, characterized in that: The method for determining the deviation of the moving rod curve in step 7) is as follows: Determine the standard curves for lifting and inserting rods according to the driving mechanism equipment; Process the standard curve: multiply the ordinate value of the standard curve (i.e., coil current value) by 1.05 to form the upper range curve X1, and multiply the value of the standard curve by 0.95 to form the lower range curve X2; curves X1 and X2 form a two-dimensional array with a time interval of h, which are recorded as XA = {(a0, t0), (a1, t1) ... (aNA, tNA), XB = {(b0, t0), (b1, t1) ... (bNB, tNB)}; the moving rod curve extracted in step 6) forms an array XC = {(c0, t0), (c1, t1) ... (cNC, tNC)} with a time interval of h; NA, NB, NC are the number of points in each array, and the same value is 100-2000; a, b, c in the array represent the ordinate on each curve, i.e., the coil current value, t represents the abscissa, i.e., the time point, and the suffix number represents the data sequence number of the interval; Compare each two-dimensional array XC with XA and XB according to the ordinates corresponding to the interval time points: if the array value of XC, that is, the ordinate value, exceeds the range limited by the ordinate value of XA and the ordinate value of XB, it is considered that an out-of-tolerance exists; otherwise, the curve is normal.

11. The online monitoring method for a control rod drive mechanism according to claim 1, characterized in that: In the step 5), high-frequency ripples above 5 Hz are filtered out.

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