Automatic calibration and verification method for vortex signal of heat transfer tubeTechnical Field
The invention relates to the field of nuclear power station overhaul, in particular to an automatic calibration and verification method for vortex signals of a heat transfer tube.
Background
The high temperature and pressure medium used by the steam generator to cool the primary circuit of the nuclear power plant is a fragile component in the whole primary circuit, and the evaporator heat transfer tubes must be subjected to nondestructive inspection periodically according to the requirements of relevant inspection specifications. The mature and reliable detection scheme is to perform eddy current detection on the evaporator heat transfer tube, and related detection equipment and detection method have high requirements in-service detection of nuclear power equipment.
The whole eddy current detection system comprises detection hardware and related software, wherein the hardware comprises an eddy current instrument, a cable, an eddy current probe, a control box, a positioner, a puller, a communication system and the like; the software part comprises management software, acquisition software, analysis software, transmission software, cooperation management software, locator control software, puller control software and the like. When the detection of the evaporator heat exchange tube is implemented, the analysis of the defects is mainly carried out by an analysis personnel through analysis software. The main process comprises the following steps: device connection and testing, parameter setting, data analysis (primary analysis, secondary analysis, and result verification), result entry reporting, data management, and inspection report output. The parameter setting part is one of the core parts of the whole analysis process, and a calibration standard is established through the process and is used as a reference basis for judging defects. And when the collection is completed, checking the current calibrated standard is needed to be used as a necessary condition for the validity of the data. At present, the analysis result is directly affected due to the deviation of different analysts when the analysts perform setting and checking and signal acquisition and calibration. Meanwhile, manual calibration and check are required to occupy a certain analysis time, and the whole detection progress is affected.
Disclosure of Invention
1. The purpose is as follows:
the invention aims to solve the technical problems that: aiming at the problems of signal calibration and check in heat exchange tube detection, the method for determining the calibration structure and the signal range based on signal identification is provided, the calibration signal is automatically calibrated, and after data analysis is completed, the deviation of the calibration signal is automatically checked.
2. The technical scheme is as follows:
in order to achieve the purpose, the invention adopts the following technical scheme:
step one: positioning each calibration signal of the calibration tube:
1. the calibration tube signals are collected, and the calibration tube signals can be collected independently or selected from the detection signals of the whole heat transfer tube (the guide tube contains the calibration tube and the signals are successfully collected);
2. and carrying out signal characteristic analysis according to various defect signals to form a characteristic library and form a characteristic library of all defects.
3. Positioning the pipe end signals, measuring and matching the data, and according to the signal length, referring to the pipe end signal length stored in the signal feature library, allowing redundancy of plus or minus 20%, wherein the scanning steps are set to be more than 3 data points and not more than 25% of the pipe end signal length; when n pipe end signals are found, the length between the signal center points is calculated, and the point with the length closest to the actual calibration pipe length is taken as the pipe end signal.
The calculation formula of two point lengths:
length = number of data points between two points/sampling rate probe acquisition speed.
4. According to pipe end positioning, positioning the calibration signals in the two pipe ends one by one, calibrating the structural size of the pipe, referring to fig. 1, adopting an eddy current signal characteristic analysis method to perform characteristic matching, and simultaneously checking the position of the positioning signals according to the actual physical size position. The calculation method for converting the actual length into the estimated data point length comprises the following steps:
estimated data point = structure length/acquisition speed.
Step two: calibrating the calibration signal:
the automatic calibration is divided into two types: ASME and RSEM specifications.
1. Amplitude normalization, measuring 100% of through hole signals, and the measuring method comprises the following steps: the two points of the maximum peak-to-peak data point A, B are selected through VPP, the amplitude is calculated, and the formula is as follows:
calculating a normalized coefficient Beta:
ASME specification: beta=6/Vol
RSEM Specification: beta=8/Vol
2. Phase normalization, measuring 100% of through hole signals, and the measuring method comprises the following steps: the phase is calculated by VPP selecting the two points of the largest peak-to-peak data point A, B:
Phase＝180.0-(Math.Atan2((Ax-Bx),(Ay-By))*(180.0/
Math.PI))；
wherein: math.pi=3.14159
Calculating normalized rotation degrees:
Ration＝Phase-40
step three: creating a calibration curve:
the ASME calibration tube uses 100% -60% -20% of the created phase wound depth curve, and the RSEM calibration tube uses 100% -40% -10% of the drawn phase wound depth curve.
1. Selecting calibration curve points, wherein ASME standards select 100% -60% -20% of three structural points, and RSEM standards select 100% -40% -10% of three calibration points;
2. according to the phase values measured by the three calibration points; and establishing a phase depth coordinate system, connecting three points, and generating a corresponding fitting function. And calculating and displaying the phase corresponding to each depth in the middle.
Step four: defect analysis
For any defect signal, the amplitude and phase are calculated as follows:
V＝Vraw*Beta.
where Vraw is the original VPP measured amplitude.
P＝Praw–Ration
Where Vraw is the original VPP measured phase.
Step five: calibration signal checking
1. Reading the calibration data, executing the step 2.1 and determining the position of the structural signal;
2. measuring 100% through holes of the structural signal by referring to the section 2.4 to obtain amplitude Ve and phase Pe;
3. and verifying that the deviation between the result and the reference value is smaller than plus or minus 10%, wherein the reference of the ASME standard amplitude is 6V, the reference of the RSEM amplitude is 8V, and the phase reference is 40.
3. Effects of
1. The calibration information can be effectively and automatically set by the method;
2. the method can automatically check the detection state.
3. One set of data this method can reduce the manual calibration time by 2-3 minutes.
Drawings
FIG. 1 is a flow chart of a method for automatically calibrating and checking eddy current signals of a heat transfer tube
Detailed Description
As shown in fig. 1, the specific steps of the present invention are as follows:
1. selecting an acquisition data set, importing open-set calibration tube data, and comprising: (1) The signal of the calibration tube is collected, the signal of the calibration tube can be collected independently or selected from the detection signals of the whole heat transfer tube, the catheter contains the calibration tube, and the signal is successfully collected;
(2) And carrying out signal characteristic analysis according to various defect signals to form a characteristic library, wherein characteristic information comprises voltage, phase, defect length, signal 8-shaped characteristics, signal change trend, signal change speed and the like, and the characteristic library of all defects is formed.
2. Positioning the calibration tube ends and structure according to the signal characteristics, comprising: (1) Positioning the pipe end signals, measuring and matching the data, and according to the signal length, referring to the pipe end signal length stored in the signal feature library, allowing redundancy of plus or minus 20%, wherein the scanning steps are set to be more than 3 data points and not more than 25% of the pipe end signal length; when n pipe end signals are found, calculating the length between signal center points, and taking the point with the length closest to the length of the actual calibration pipe as the pipe end signal; the calculation formula of two point lengths:
length = number of data points between two points/sampling rate probe acquisition speed.
(2) Positioning the calibration signals in the two pipe ends one by one according to the pipe end positioning, performing feature matching by adopting an eddy current signal feature analysis method, and checking the position of the positioning signals according to the actual physical size position. The calculation method for converting the actual length into the estimated data point length comprises the following steps:
estimated data point = structure length/acquisition speed.
3. According to ASME standard or RSEM standard, calibrating the calibration signal automatically to generate a calibration curve, including: (1) Amplitude normalization, measuring 100% of through hole signals, and the measuring method comprises the following steps: the two points of the maximum peak-to-peak data point A, B are selected through VPP, the amplitude is calculated, and the formula is as follows:
calculating a normalized coefficient Beta:
ASME specification: beta=6/Vol;
RSEM Specification: beta=8/Vol;
(3) Phase normalization, measuring 100% of through hole signals, and the measuring method comprises the following steps: the phase is calculated by VPP selecting the two points of the largest peak-to-peak data point A, B:
Phase＝180.0-(Math.Atan2((Ax-Bx),(Ay-By))*(180.0/
Math.PI))；
wherein: math.pi=3.14159
Calculating normalized rotation degrees:
Ration＝Phase-40。
(3) Selecting calibration curve points, wherein ASME standards select 100% -60% -20% of three structural points, and RSEM standards select 100% -40% -10% of three calibration points; according to the phase values measured by the three calibration points; and establishing a phase depth coordinate system, connecting three points, and generating a corresponding fitting function. And calculating and displaying the phase corresponding to each depth in the middle.
4. Measuring the data defect of the actual detection tube according to the calibration curve and the BETA coefficient and the rotation angle set by calibration: for any defect signal, the amplitude and phase are calculated as follows:
v=vraw x Beta, where Vraw is the original VPP measured amplitude;
p=praw-station, where Vraw is the original VPP measured phase.
5. Checking the calibration signal of the end calibration tube, comprising the following steps:
(1) Reading the calibration data, executing the step 2.1 and determining the position of the structural signal;
(2) Measuring 100% through holes of the structural signal by referring to the section 2.4 to obtain amplitude Ve and phase Pe;
(3) And verifying that the deviation between the result and the reference value is smaller than plus or minus 10%, wherein the reference of the ASME standard amplitude is 6V, the reference of the RSEM amplitude is 8V, and the phase reference is 40.