Anomaly detection device, anomaly detection method, and program for a control rod drive system.

Abstract

This system prevents the failure to detect abnormalities in the drive system due to the electrical parameters of the electric motor used in the drive system and the mechanical parameters of the drive system itself. [Solution] The anomaly detection device 20 comprises a specific section extraction unit 22, a feature quantity calculation unit 24, and an anomaly diagnosis unit 25. The specific section extraction unit 22 divides and extracts the phase current (motor phase current 31) flowing through the motor 11 used in the control rod drive device 10 into specific section data (section current data 32). The feature quantity calculation unit 24 calculates feature quantities to be used for diagnosis in the anomaly diagnosis unit 25. The anomaly diagnosis unit 25 diagnoses whether or not there is an anomaly in the control rod drive device 10 based on the feature quantities. The feature quantity calculation unit 24 calculates the natural frequency of the entire control rod drive device 10 based on the electrical parameters of the motor 11 and the mechanical parameters of the control rod drive device 10, and calculates feature quantities using the natural frequency and the applied voltage frequency to the motor 11.

Description

Technical Field

[0001] The present invention relates to an abnormality detection device for a control rod drive device, an abnormality detection method, and a program.

Background Art

[0002] In recent years, the spread of IoT (Internet of Things) and the advancement of AI (Artificial Intelligence) have coincided with a decrease in the working population. As a result, technologies that actively use information obtained by sensors and the like in maintenance work have attracted attention for the purpose of improving the efficiency and reducing the manpower of maintenance work. Among them, in the control rod drive device of nuclear power generation facilities, diagnostic methods using sensor information have been proposed to reduce the amount of inspection work. Representative examples of sensor types include vibration sensors and position sensors, but a method using a current sensor has attracted particular attention due to ease of installation.

[0003] For example, in Patent Document 1, a method has been proposed for diagnosing a low-speed abnormal operation by detecting that the current of an electric motor (motor) that drives a control drive device is lower than a reference value.

[0004] Further, in Patent Document 2, although not specific to nuclear power generation facilities, a method for diagnosing an abnormality of a speed reducer is presented by extracting the amplitude peak value in the frequency region corresponding to the natural frequency of the speed reducer connected to the electric motor from the frequency spectrum of the current of the electric motor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the prior art described in Patent Document 1 has a problem in that it may not be possible to detect abnormalities in the control drive device depending on the electrical parameters of the electric motor used in the control drive device. For example, the prior art described in Patent Document 1 may not be able to detect abnormalities depending on the ratio of the D-axis current Id, which contributes to the generation of magnetic flux in the electric motor, and the Q-axis current Iq, which contributes to the generation of torque. This point will be explained below with reference to Figures 8A and 8B. Figure 8A is an explanatory diagram showing the current change when the Q-axis current Iq >> D-axis current Id. Figure 8B is an explanatory diagram showing the current change when the D-axis current Id >> Q-axis current Iq. Note that "D-axis" refers to the same direction as the magnetic field lines from the N pole to the S pole of a permanent magnet. Also, "Q-axis" refers to the direction that intersects the D-axis at a 90-degree angle.

[0007] For example, as shown in Figure 8A, suppose the Q-axis current Iq changes while the Q-axis current Iq is greater than the D-axis current Id. In this case, the Q-axis current Iq reacts to the load change, and the amount of change ΔIq in the Q-axis current Iq affects the entire motor current Ia to a similar extent. Therefore, the prior art described in Patent Document 1 can detect abnormalities using the effective value of the motor's phase current, etc. However, for example, as shown in Figure 8B, if the Q-axis current Iq is sufficiently smaller than the D-axis current Id, even if the Q-axis current Iq changes, the effect of the amount of change ΔIq in the Q-axis current Iq on the entire motor current Ia becomes small. In this case, even if an abnormality occurs in the control rod drive device accompanied by pulse-like load fluctuations, the instantaneous current change becomes small due to the principle described above, and furthermore, if the effective value or average value of the phase current is calculated in this state, the amount of change ΔIq in the Q-axis current Iq becomes even smaller. Therefore, depending on the ratio of the D-axis current to the Q-axis current, the change in the Q-axis current Iq, ΔIq, may be obscured by measurement noise, potentially preventing the detection of abnormalities in the control rod drive mechanism.

[0008] Furthermore, the conventional technology described in Patent Document 2 has the problem that abnormalities in the drive unit may not be detectable depending on the mechanical parameters of the drive unit. For example, in the conventional technology described in Patent Document 2, it may be difficult to capture vibrations with the motor current when the drive unit has a structure that makes it difficult for resonance to occur. For example, the conventional technology described in Patent Document 2 performs diagnosis by utilizing the increase in the amplitude of the natural frequency of the mechanical device being diagnosed when an abnormality occurs. However, some mechanical devices being diagnosed have small spring and damper components and a structure that makes it difficult for resonance to occur. Therefore, when the drive unit has a structure that makes it difficult for resonance to occur, it may be difficult to capture vibrations with the motor current even if pulse-like load fluctuations occur.

[0009] The present invention was made to solve the aforementioned problems, and its main objective is to provide an abnormality detection device, an abnormality detection method, and a program that suppress the inability to detect abnormalities in a drive system due to the electrical parameters of the electric motor used in the drive system and the mechanical parameters of the drive system. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides an abnormality detection device for a control rod drive device, comprising: a specific section extraction unit that divides and extracts the phase current flowing through an electric motor used in a control rod drive device that performs insertion and withdrawal operations of control rods into the reactor core into specific section data; a feature quantity calculation unit that calculates feature quantities used for diagnosing the control rod drive device; and an abnormality diagnosis unit that diagnoses whether or not there is an abnormality in the control rod drive device based on the feature quantities, wherein the feature quantity calculation unit calculates the natural frequency of the entire control rod drive device based on the electrical parameters of the electric motor and the mechanical parameters of the control rod drive device, and calculates the feature quantities using the natural frequency and the applied voltage frequency to the electric motor. Other methods will be described later. [Effects of the Invention]

[0011] According to the present invention, it is possible to suppress the situation in which abnormalities in the drive system cannot be detected due to the electrical parameters of the electric motor used in the drive system and the mechanical parameters of the drive system. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of the control rod drive device and the abnormality detection device according to this embodiment. [Figure 2] This is a schematic diagram of the control rod drive system. [Figure 3] This is a hardware configuration diagram showing an example of a computer that implements the functions of an anomaly detection device. [Figure 4] This is a flowchart showing the operation of the anomaly detection device. [Figure 5] This is a graph showing time-series data of electric motor current. [Figure 6] This is an explanatory diagram showing an example of the first feature. [Figure 7] This is an explanatory diagram showing an example of the second feature. [Figure 8A] This diagram illustrates the current change when the Q-axis current Iq >> D-axis current Id. [Figure 8B] This diagram illustrates the current change when the D-axis current Id >> Q-axis current Iq. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail with reference to the drawings. Note that each figure is merely a schematic representation to the extent necessary for a thorough understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. Furthermore, in each figure, common or similar components are denoted by the same reference numerals, and their redundant descriptions are omitted.

[0014] <Configuration of the control rod drive unit and abnormality detection unit> Hereinafter, referring to FIGS. 1 and 2, the configurations of the control rod drive device 10 and the abnormality detection device 20 according to the present embodiment will be described. The abnormality detection device 20 is a device that detects the presence or absence of an abnormality in the control rod drive device 10. The control rod drive device 10 is a device for moving a control rod 16 for controlling the output power of a nuclear reactor up and down (inserting / withdrawing) in a nuclear power generation facility. FIG. 1 is a schematic configuration diagram of the abnormality detection device 20 according to the present embodiment. FIG. 2 is a schematic configuration diagram of the control rod drive device 10.

[0015] In the present embodiment, a case will be described assuming that the abnormality detection device 20 inputs a single-phase motor phase current flowing through the motor 11 (motor) used in the control rod drive device 10 to detect the presence or absence of an abnormality in the control rod drive device 10. Here, first, the configuration of the control rod drive device 10 will be described. Then, the configuration of the abnormality detection device 20 will be described.

[0016] The control rod drive device 10 performs an insertion operation and a withdrawal operation of a control rod with respect to the core in a nuclear power generation facility. As shown in FIGS. 1 and 2, as a configuration for this purpose, the control rod drive device 10 includes a motor 11, a coupler 12, a ball screw 13, a ball nut 14, a connecting rod 15, a control rod 16, and a power source 17.

[0017] The power source 17 supplies a periodic three-phase rectangular wave voltage (a voltage in a state where each phase is shifted by 120 degrees) or a sine wave voltage to the motor 11 by open-loop (feedforward) control to drive the motor 11. In the description of the present embodiment, the description will be limited to the rectangular wave voltage, but the same description will apply when driving with a sine wave voltage. The type of the motor 11 may be any of a magnet motor, a stepping motor, and an induction motor.

[0018] The shaft of the electric motor 11, driven by the power supply 17, is coupled to the ball screw 13 by the coupler 12 and rotates synchronously. The rotation of the electric motor 11's shaft causes the ball nut 14 to move up and down, and the connecting rod 15 and control rod 16 resting on the ball nut 14 also move up and down. Such a control rod drive device 10 may experience malfunctions accompanied by pulse-like load fluctuations due to, for example, the inclusion of foreign matter, insufficient lubrication, contact with the housing, or the detachment of parts.

[0019] The anomaly detection device 20 detects anomalies in the control rod drive device 10 that involve pulse-like load fluctuations. As shown in Figure 1, the anomaly detection device 20 according to this embodiment includes a specific section extraction unit 22, a frequency conversion unit 23, a feature quantity calculation unit 24, an anomaly diagnosis unit 25, and a transmission unit 26.

[0020] The specific section extraction unit 22 is a component that divides and extracts specific section data (section current data 32) from the phase current (motor phase current 31) flowing through the electric motor 11 (motor) used in the control rod drive device 10, which performs insertion and withdrawal operations of the control rods 16 into the reactor core.

[0021] The frequency conversion unit 23 is a component that converts phase current (motor phase current 31) into a frequency domain signal. The frequency conversion unit 23 converts specific section data (section current data 32) from a time domain signal into a frequency domain signal.

[0022] The feature calculation unit 24 is a component that calculates feature quantities used for diagnosis in the anomaly diagnosis unit 25. The feature calculation unit 24 calculates the natural frequency of the entire control rod drive unit 10 based on the electrical parameters of the electric motor 11 and the mechanical parameters of the control rod drive unit 10, and calculates feature quantities using this natural frequency and the applied voltage frequency to the electric motor 11.

[0023] The abnormality diagnosis unit 25 is a component that diagnoses whether or not there is an abnormality in the control rod drive device 10 based on characteristic quantities.

[0024] The transmission unit 26 is a component that transmits arbitrary information to the outside. The transmission unit 26 transmits the diagnostic results of the control rod drive unit 10, performed by the abnormality diagnosis unit 25, to one or more of the following: the control device (not shown) of the control rod drive unit 10, the control device (not shown) of the electric motor 11, and the control system (not shown) of the power plant (not shown), display (not shown), speaker (not shown), and lamp (not shown).

[0025] The abnormality detection device 20 is electrically connected to the control rod drive device 10 via a current sensor 21. The current sensor 21 is a component that functions as a current acquisition unit to acquire the motor phase current 31 flowing through the electric motor 11 used in the control rod drive device 10.

[0026] The anomaly detection device 20 according to this embodiment is implemented by a computer 900 having a configuration such as that shown in Figure 3. Figure 3 is a hardware configuration diagram showing an example of a computer 900 that implements the functions of the anomaly detection device 20. The computer 900 includes a CPU 901, ROM 902, RAM 903, SSD 904, input / output interface 905 (labeled as input / output I / F (Interface) in Figure 3), communication interface 906 (labeled as communication I / F in Figure 3), and media interface 907 (labeled as media I / F in Figure 3). The computer 900 may be equipped with an HDD (Hard Disk Drive) instead of the SSD 904, or it may be equipped with an HDD in addition to the SSD 904. The computer 900 is also connected to input devices 910 such as a keyboard and mouse, and output devices 911 such as a display.

[0027] The CPU 901 operates based on the control program PR20 stored in the ROM 902 or SSD 904, and realizes each component shown in Figure 1. The ROM 902 stores the boot program executed by the CPU 901 when the computer 900 starts up, as well as programs related to the computer 900's hardware. The control program PR20 is stored in the recording medium 912 and installed from the recording medium 912 to the computer 900. Alternatively, the control program PR20 is stored in a server (not shown) and downloaded from the server to the computer 900 via a network (not shown).

[0028] <Operation of the abnormality detection device> The operation of the anomaly detection device 20 will be explained below with reference to Figure 4. Figure 4 is a flowchart showing the operation of the anomaly detection device 20.

[0029] The abnormality detection device 20 receives at least one phase motor phase current 31 from the control rod drive unit 10 as current data (time-series data) via the current sensor 21 (current acquisition unit). The motor phase current 31 is the multi-phase (e.g., 3-phase) current that flows through the motor 11. The motor phase current 31 input to the abnormality detection device 20 as current data (time-series data) is input to the steady-state standby unit 22a of the specific section extraction unit 22. Then, as shown in Figure 4, the abnormality detection device 20 waits in the steady-state standby unit 22a of the specific section extraction unit 22 until the motor phase current 31 of the motor 11 reaches a steady state (step S110).

[0030] The process of step S110 will be explained with reference to Figure 5. Figure 5 is a graph showing the time-series data of the motor phase current 31. In the control rod drive unit 10, the motor 11 accelerates and decelerates immediately after starting operation (start of driving of the ball screw 13) and just before stopping. Therefore, as shown in Figure 5, the frequency and amplitude of the motor phase current 31 change transiently. The transient state of the motor phase current 31 is unstable in terms of phase and amplitude, making it unsuitable as data to be used to diagnose (detect) the presence or absence of abnormality in the control rod drive unit 10. Therefore, the abnormality detection device 20 waits using the steady-state standby unit 22a of the specific section extraction unit 22 until the amplitude and frequency of the motor phase current 31 fall within a certain range (for example, within ±1%), that is, until the motor phase current 31 reaches a steady state. In this case, the abnormality detection device 20 may not wait for the amplitude or frequency of the motor phase current 31 to fall within a certain range, but rather wait until a specific time or period has elapsed since the start of operation of the control rod drive device 10. In other words, the abnormality detection device 20 waits until the phase current (motor phase current 31) reaches a steady state after a specific time has elapsed since the start of operation of the motor 11, or after the periodic fluctuation of the current has reached a specific number of times.

[0031] Returning to Figure 4, after step S110, the abnormality detection device 20 divides and holds the motor phase current 31 at specific time intervals using the current holding unit 22b of the specific section extraction unit 22, thereby extracting it as section current data 32 (specific section data) (step S120). The section current data 32 (specific section data) extracted at this time is a time-domain signal representing current data in time-series format (time-series data of phase current). The "specific time" is a time width calculated in advance, taking into account the noise level and other factors necessary for diagnosing (detecting) the presence or absence of abnormalities in the control rod drive device 10 in the frequency conversion performed later, and is, for example, a few seconds.

[0032] After step S120, the anomaly detection device 20 uses the frequency conversion unit 2 to convert the section current data 32 (specific section data) extracted in step S120 from a time-domain signal to a frequency-domain signal (step S130). In other words, the anomaly detection device 20 converts the section current data 32 from time-series current data to frequency-format current data. Possible conversion methods include, for example, the Fast Fourier Transform (FFT).

[0033] After step S130, the anomaly detection device 20 uses the feature calculation unit 24 to calculate the natural frequency of the entire control rod drive device 10 based on the electrical parameters of the electric motor 11 and the mechanical parameters of the control rod drive device 10 (step S140). The process in step S140 is performed by calculating / extracting values ​​related to the amplitude values ​​of the reference frequency band used to extract features for diagnosing (detecting) the presence or absence of anomalies in the control rod drive device 10. The reference frequency for extracting features is the natural frequency fr determined from the electrical parameters of the electric motor 11 used in the control rod drive device 10 and the mechanical parameters of the control rod drive device 10. The reference frequency for extracting features is expressed by the following equation (1), and the feature calculation unit 24 calculates it in advance by calculation or simulation.

[0034]

number

[0035] After step S140, the anomaly detection device 20 uses the feature calculation unit 24 to calculate feature quantities using the natural frequency of the entire control rod drive device 10 and the applied voltage frequency to the electric motor 11, which were calculated in step S140 (step S150).

[0036] After step S150, the anomaly detection device 20, using the anomaly diagnosis unit 25, diagnoses (detects) whether or not there is an anomaly in the control rod drive unit 10 based on the feature quantities calculated in step S150 (step S160). The anomaly diagnosis unit 25 diagnoses (detects) whether or not there is an anomaly in the control rod drive unit 10 using machine learning, statistical methods, etc.

[0037] After step S160, the abnormality detection device 20 transmits the diagnostic result of the control rod drive device 10 to any external component via the transmission unit 26 (step S170). The transmission unit 26 transmits the diagnostic result of the control rod drive device 10 to a worker or other system.

[0038] The natural frequencies of this embodiment differ from those described in Patent Document 2 in the following respects. The natural frequencies described in Patent Document 2 are resonant frequencies determined solely by the structure of the mechanical device. In contrast, the natural frequencies of this embodiment are natural vibration frequencies generated in the electrical system (electrical parameters of the electric motor 11) and the mechanical system (mechanical parameters of the control rod drive device 10), with the input considered as torque and the output as phase current. When there is a pulse-like load fluctuation (torque fluctuation), the speed of the electric motor shaft changes sharply due to the torque fluctuation, and this speed change changes the induced voltage of the electric motor, thereby changing the Q-axis current Iq. The vibration frequency generated by this sharp speed change becomes the natural frequency fr shown in equation (1) above. Furthermore, when the Q-axis current Iq is converted to a phase current, the natural frequency is divided into two frequencies, "natural frequency in equation (1) ± applied voltage frequency," according to the principle of two-phase to three-phase conversion. Based on these premises, the features extracted by the feature calculation unit 24 are described below. The feature calculation unit 24 can extract either the first feature shown in Figure 6 or the second feature shown in Figure 7.

[0039] The first feature is the amplitude component at the natural frequency ± applied voltage frequency in equation (1). Figure 6 is an explanatory diagram showing an example of the first feature. In the example shown in Figure 6, the feature calculation unit 24 extracts either or both of the amplitude components of (natural frequency + applied voltage frequency) and (natural frequency - applied voltage frequency) as features. In other words, when diagnosing an anomaly, the feature calculation unit 24 extracts either or both of the peak values ​​of the two frequencies shown in Figure 6 as features.

[0040] The second feature is the integral value of the range where the natural frequency is separated by a predetermined frequency width delta [Hz]. Figure 7 is an explanatory diagram illustrating an example of the second feature. In the example shown in Figure 7, the feature calculation unit 24 uses a predetermined frequency width delta and calculates the integral value of the frequency amplitude component in the range from (natural frequency - frequency width delta) to (natural frequency + frequency width delta) as the feature. It is advisable to use the power supply frequency as the reference value for the frequency width delta. Here, we will explain assuming that the frequency width delta is predetermined to an arbitrary value in the range of tens to hundreds of Hz. Note that the difference between the values ​​of the feature in the second example and the values ​​of the abnormal state tends to be larger than that of the feature in the first example. Therefore, it is better to use the integral, which is the second feature, when detection sensitivity is required.

[0041] Here, we will provide some additional information regarding the operation of the abnormality diagnosis unit 25. Here, we will explain assuming that the abnormality diagnosis unit 25 performs abnormality diagnosis using one of the following methods: (1), (2), or (3).

[0042] (1) The abnormality diagnosis unit 25 may, for example, determine whether the aforementioned feature quantity is above a threshold and output binary data of normal / abnormal.

[0043] (2) Alternatively, the normal features may be obtained from multiple samples, the mean and variance may be calculated in advance, and the Mahalanobis distance (MTD) may be calculated using the following equation (2). The calculated continuous value may then be output as the abnormality score of the control rod drive unit 10. Note that the method for calculating the abnormality score of the control rod drive unit 10 is not limited to the method using equation (2); machine learning or deep learning methods such as One Class SVM may also be used.

[0044]

number

[0045] (3) Furthermore, if both the mean and variance values ​​of the features of the specific interval data under normal conditions and the specific interval data to be diagnosed are calculated, a test of the difference in means (a two-sample t-test) can be performed. Therefore, the results of that test may also be output.

[0046] Furthermore, the operation of the transmission unit 26 will be explained here. The transmission unit 26 transmits the abnormality diagnosis result of the abnormality diagnosis unit 25, which was performed in step S160, to the display (not shown), speaker (not shown), lamp (not shown), etc. of the abnormality detection device 20. In this way, the abnormality detection device 20 informs the worker of the status of the control rod drive unit 10. In addition to these, the transmission unit 26 may also transmit the abnormality diagnosis result of the abnormality diagnosis unit 25 to the control device (not shown) of the control rod drive unit 10, the control device (not shown) of the electric motor 11 (motor), and the control system (not shown) of the power plant (not shown). The abnormality detection device 20 may also use the abnormality diagnosis result of the abnormality diagnosis unit 25 as feedback data for equipment control such as emergency stop or degraded operation.

[0047] Such anomaly detection device 20 can detect anomalies in the control rod drive device 10 that involve pulse-like load fluctuations.

[0048] <Main features of the anomaly detection device> The anomaly detection device 20 according to this embodiment can be configured to have the following features. (1) As shown in Figure 1, the anomaly detection device 20 according to this embodiment comprises a specific section extraction unit 22, a feature quantity calculation unit 24, and an anomaly diagnosis unit 25. The specific section extraction unit 22 is a component that divides and extracts the phase current (motor phase current 31) flowing through the electric motor 11 (motor) used in the control rod drive device 10, which performs insertion and withdrawal operations of control rods 16 into specific section data (section current data 32). The feature quantity calculation unit 24 is a component that calculates feature quantities used for diagnosis in the anomaly diagnosis unit 25. The anomaly diagnosis unit 25 is a component that diagnoses whether or not there is an anomaly in the control rod drive device 10 based on the feature quantities. The feature quantity calculation unit 24 calculates the natural frequency of the entire control rod drive device 10 based on the electrical parameters of the electric motor 11 (motor) and the mechanical parameters of the control rod drive device 10, and calculates feature quantities using the natural frequency and the applied voltage frequency to the electric motor 11 (motor).

[0049] The abnormality detection device 20 according to this embodiment can detect abnormalities accompanied by pulse-like load fluctuations occurring in the control rod drive device 10, even under motor driving conditions such as D-axis current Id >> Q-axis current Iq, or in situations where resonance of the mechanical device to be diagnosed is unlikely to occur. Such an abnormality detection device 20 can suppress the inability to detect abnormalities in the control rod drive device 10 due to the electrical parameters of the motor 11 used in the control rod drive device 10 and the mechanical parameters of the control rod drive device 10.

[0050] (2) In the abnormality detection device 20 described in item (1) above, the electric motor 11 is one of a stepping motor, a magnet motor, or an induction motor.

[0051] In this embodiment, the abnormality detection device 20 can detect abnormalities accompanied by pulse-like load fluctuations occurring in the control rod drive device 10, since the electric motor 11 is one of a stepping motor, a magnet motor, or an induction motor.

[0052] (3) The abnormality detection device 20 described in item (1) above is further provided with a frequency conversion unit 23 that converts the phase current (motor phase current 31) into a frequency domain signal. The phase current (motor phase current 31) enters a steady state after a specific time has elapsed since the motor 11 started to drive, or after the periodic fluctuation of the current has reached a specific number of times. Thereafter, the specific section extraction unit 22 extracts specific section data (section current data 32) by dividing the phase current (motor phase current 31) into predetermined time widths. The frequency conversion unit 23 converts the specific section data from a time domain signal into a frequency domain signal. The feature calculation unit 24 calculates the natural frequency of the entire control rod drive device 10 based on the electrical parameters of the motor 11 and the mechanical parameters of the control rod drive device 10.

[0053] The abnormality detection device 20 according to this embodiment extracts specific section data (section current data 32) after the phase current (motor phase current 31) has reached a steady state, and converts this specific section data into a frequency domain signal. The abnormality detection device 20 then calculates the natural frequency of the entire control rod drive device 10 based on the electrical parameters of the motor 11 and the mechanical parameters of the control rod drive device 10. Such an abnormality detection device 20 can prevent the abnormality of the control rod drive device 10 from becoming undetectable due to the electrical parameters of the motor 11 used in the control rod drive device 10 and the mechanical parameters of the control rod drive device 10.

[0054] (4) As shown in Figure 6, in the anomaly detection device 20 described in item (3) above, the feature quantity calculation unit 24 extracts either or both of the amplitude components of (natural frequency + applied voltage frequency) and (natural frequency - applied voltage frequency) as feature quantities.

[0055] The anomaly detection device 20 according to this embodiment can extract (calculate) characteristic quantities using the natural frequency and the applied voltage frequency. Based on these characteristic quantities, the anomaly detection device 20 can diagnose whether or not there is an anomaly in the control rod drive device 10.

[0056] (5) As shown in Figure 7, in the anomaly detection device 20 described in item (3) above, the feature calculation unit 24 calculates the integral value of the frequency amplitude component in the range from (natural frequency - frequency width delta) to (natural frequency + frequency width delta) as a feature, with a predetermined frequency width delta.

[0057] The anomaly detection device 20 according to this embodiment can calculate feature quantities using the natural frequency and the frequency width delta. Based on these feature quantities, the anomaly detection device 20 can diagnose whether or not there is an anomaly in the control rod drive device 10.

[0058] (6) In the anomaly detection device 20 described in item (4) or item (5) above, the feature calculation unit 24 calculates the natural frequency of the entire control rod drive device 10 using the following function. This function includes the number of pole pairs and inductance of the motor 11 as electrical parameters of the motor, and the combined inertia of the control rod drive device 10 and the motor 11 as mechanical parameters of the control rod drive device 10.

[0059] The abnormality detection device 20 according to this embodiment calculates the natural frequency of the entire control rod drive unit 10 using a function that includes the number of pole pairs and inductance of the electric motor 11, as well as the combined inertia of the control rod drive unit 10 and the electric motor 11. Such an abnormality detection device 20 can suppress the inability to detect abnormalities in the control rod drive unit 10 due to the electrical parameters of the electric motor 11 used in the control rod drive unit 10 and the mechanical parameters of the control rod drive unit 10.

[0060] (7) The abnormality detection device 20 described in item (6) above further comprises a transmission unit 26 for transmitting arbitrary information to the outside. The transmission unit 26 transmits the diagnostic results of the control rod drive device 10 performed by the abnormality diagnosis unit 25 to one or more of the following: the display (not shown), speaker (not shown), lamp (not shown) of the abnormality detection device 20, and the control device of the control rod drive device 10 (not shown), the control device of the electric motor 11 (motor) (not shown), and the control system of the power plant (not shown).

[0061] The abnormality detection device 20 according to this embodiment can transmit the diagnostic results of the control rod drive device 10 to any component.

[0062] (8) In the abnormality detection device 20 described in item (1) above, the abnormality diagnosis unit 25 acquires multiple normal characteristic quantities as sample values ​​and calculates the mean and variance values ​​in advance, and calculates the Mahalanobis distance at the time of diagnosis. The abnormality diagnosis unit 25 then diagnoses whether or not there is an abnormality in the control rod drive device 10 based on the Mahalanobis distance.

[0063] The abnormality detection device 20 according to this embodiment can diagnose whether or not there is an abnormality in the control rod drive device 10 based on the Mahalanobis distance.

[0064] (9) In the abnormality detection device 20 described in item (1) above, the abnormality diagnosis unit 25 acquires the normal characteristic values ​​as sample values, and at the time of diagnosis calculates the mean and variance of the normal characteristic values ​​and the characteristic values ​​of the specific interval data (interval current data 32) to be diagnosed. Then, the abnormality diagnosis unit 25 performs a test of the difference in mean values ​​(two-sample t-test) based on the mean and variance of the characteristic values ​​of the specific interval data (interval current data 32) to diagnose whether or not there is an abnormality in the control rod drive device 10.

[0065] The abnormality detection device 20 according to this embodiment can diagnose whether or not there is an abnormality in the control rod drive device 10 based on the mean and variance values ​​of the feature quantities of specific section data (section current data 32).

[0066] (10) As shown in Figure 4, the anomaly detection method according to this embodiment includes a specific interval extraction step (step S120), a feature quantity calculation step (step S150), and an anomaly diagnosis step (step S160). The specific interval extraction step (step S120) is a step of dividing and extracting the phase current (motor phase current 31) flowing through the motor 11 (motor) used in the control rod drive device 10 that performs insertion and withdrawal operations of the control rods 16 into specific interval data (interval current data 32). The feature quantity calculation step (step S150) is a step of calculating feature quantities used for diagnosing the control rod drive device 10. The anomaly diagnosis step (step S160) is a step of diagnosing whether or not there is an anomaly in the control rod drive device 10 based on the feature quantities. In the feature calculation process (step S150), the natural frequency of the entire control rod drive unit 10 is calculated based on the electrical parameters of the electric motor 11 and the mechanical parameters of the control rod drive unit 10, and feature quantities are calculated using this natural frequency and the applied voltage frequency to the electric motor 11.

[0067] The abnormality detection method according to this embodiment can detect abnormalities accompanied by pulse-like load fluctuations occurring in the control rod drive unit 10, even under motor driving conditions such as D-axis current Id >> Q-axis current Iq, or in situations where resonance of the mechanical device being diagnosed is unlikely to occur. Such an abnormality detection method can suppress the possibility that abnormalities in the control rod drive unit 10 may become undetectable due to the electrical parameters of the motor 11 used in the control rod drive unit 10 and the mechanical parameters of the control rod drive unit 10.

[0068] (11) The program according to this embodiment (control program PR20) is a program that causes a computer to perform a specific interval extraction step (step S120), a feature calculation step (step S150), and an anomaly diagnosis step (step S160).

[0069] The program according to this embodiment can implement the anomaly detection method described in item (10) above.

[0070] As described above, the abnormality detection device 20 according to this embodiment can suppress the situation in which abnormalities in the control rod drive device 10 cannot be detected due to the electrical parameters of the electric motor 11 used in the control rod drive device 10 and the mechanical parameters of the control rod drive device 10.

[0071] The present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace some of the configurations of the embodiments with other configurations, and it is also possible to add other configurations to the configurations of the embodiments. In addition, it is possible to add, delete, or replace some of the configurations of each configuration with other configurations. [Explanation of Symbols]

[0072] 10 Control rod drive device 11. Electric motor 12 Coupler 13 Ball screw 14 Ball Nut 15 Connecting rod 16 control rods 17 Power supply 20 Anomaly detection device (computer) 21 Current sensor (current acquisition unit) 22 Specific interval extraction unit 22a Steady-state standby section 22b Current holding part 23 Frequency conversion section 24 Feature Calculation Unit 25. Department of Abnormal Diagnosis 26 Transmission section 31 Motor phase current (phase current) 32 Section Current Data (Specific Section Data) 900 Computers 901 CPU 902 ROM 903 RAM 904 SSD 905 Input / Output Interface 906 Communication Interface 907 Media Interface 910 Input device 911 Output device 912 Recording media PR20 Control Program

Claims

1. A specific section extraction unit divides and extracts the phase current flowing through the electric motor used in the control rod drive device, which performs the insertion and withdrawal operations of control rods into the reactor core, into specific section data. A feature quantity calculation unit that calculates feature quantities used for diagnosing the control rod drive device, The system includes an abnormality diagnosis unit that diagnoses whether or not there is an abnormality in the control rod drive device based on the aforementioned feature quantities, The feature calculation unit calculates the natural frequency of the entire control rod drive system based on the electrical parameters of the electric motor and the mechanical parameters of the control rod drive system, and calculates the feature quantity using the natural frequency and the voltage frequency applied to the electric motor. An abnormality detection device for a control rod drive system, characterized by the above.

2. In the abnormality detection device for the control rod drive device according to claim 1, The electric motor is one of a stepping motor, a magnet motor, or an induction motor. An abnormality detection device for a control rod drive system, characterized by the above.

3. In the abnormality detection device for the control rod drive device according to claim 1, The unit further comprises a frequency conversion unit that converts the aforementioned phase current into a frequency domain signal, The specified interval extraction unit extracts the specified interval data by dividing the phase current into predetermined time intervals after a specific time has elapsed since the motor started driving or after the current periodic fluctuation has reached a specific number of times, and after the phase current has reached a steady state. The frequency conversion unit converts the specific interval data from a time-domain signal to a frequency-domain signal. The feature calculation unit calculates the natural frequency of the entire control rod drive system based on the electrical parameters of the electric motor and the mechanical parameters of the control rod drive system. An abnormality detection device for a control rod drive system, characterized by the above.

4. In the abnormality detection device for the control rod drive device according to claim 3, The feature calculation unit extracts either or both of the amplitude components of (natural frequency + applied voltage frequency) and (natural frequency - applied voltage frequency) as features. An abnormality detection device for a control rod drive system, characterized by the above.

5. In the abnormality detection device for the control rod drive device according to claim 3, The feature calculation unit calculates the integral value of the frequency amplitude components in the range from (natural frequency - frequency width delta) to (natural frequency + frequency width delta) as a feature, with a predetermined frequency width of delta. An abnormality detection device for a control rod drive system, characterized by the above.

6. In the abnormality detection device for the control rod drive device according to claim 4 or claim 5, The feature calculation unit calculates the natural frequency of the entire control rod drive system using a function that includes the number of pole pairs and inductance of the motor as electrical parameters of the motor, and the combined inertia of the control rod drive system and the motor as mechanical parameters of the control rod drive system. An abnormality detection device for a control rod drive system, characterized by the above.

7. In the abnormality detection device for the control rod drive device according to claim 6, It further includes a transmission unit for transmitting arbitrary information to the outside, The transmission unit transmits the diagnostic results of the control rod drive unit, performed by the abnormality diagnosis unit, to one or more of the following: the display, speaker, and lamp of the abnormality detection device, and the control device of the control rod drive unit, the control device of the electric motor, and the power plant control system. An abnormality detection device for a control rod drive system, characterized by the above.

8. In the abnormality detection device for the control rod drive device according to claim 1, The abnormality diagnosis unit acquires multiple normal characteristic quantities as sample values, calculates the mean and variance values ​​in advance, calculates the Mahalanobis distance at the time of diagnosis, and diagnoses whether or not there is an abnormality in the control rod drive device based on the Mahalanobis distance. An abnormality detection device for a control rod drive system, characterized by the above.

9. In the abnormality detection device for the control rod drive device according to claim 1, The abnormality diagnosis unit acquires the normal characteristics as sample values, calculates the mean and variance of the normal characteristics and the characteristics of the specific interval data to be diagnosed during diagnosis, performs a test of the difference between the mean and variance, and diagnoses whether or not there is an abnormality in the control rod drive device. An abnormality detection device for a control rod drive system, characterized by the above.

10. A specific section extraction process is performed to divide the phase current flowing through the electric motor used in the control rod drive system, which performs the insertion and withdrawal operations of control rods into the reactor core, into specific section data and extract it; A feature calculation step for calculating feature quantities used in diagnosing the control rod drive device, The process includes an abnormality diagnosis step for diagnosing whether or not there is an abnormality in the control rod drive device based on the aforementioned feature quantities, In the feature calculation step, the natural frequency of the entire control rod drive unit is calculated based on the electrical parameters of the electric motor and the mechanical parameters of the control rod drive unit, and the feature quantity is calculated using the natural frequency and the applied voltage frequency to the electric motor. A method for detecting abnormalities in a control rod drive device, characterized by the features described above.

11. On the computer, A specific section extraction process is performed to divide the phase current flowing through the electric motor used in the control rod drive system, which performs the insertion and withdrawal operations of control rods into the reactor core, into specific section data and extract it; A feature calculation step for calculating feature quantities used in diagnosing the control rod drive device, A program that performs an abnormality diagnosis step, which diagnoses whether or not there is an abnormality in the control rod drive device based on the aforementioned feature quantities, In the feature calculation step, the natural frequency of the entire control rod drive unit is calculated based on the electrical parameters of the electric motor and the mechanical parameters of the control rod drive unit, and the feature quantity is calculated using the natural frequency and the voltage frequency applied to the electric motor. A program for that purpose.

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