JP2009293931A - Device and method for assessing effect of motor system in plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an assessment device and method for easily assessing in advance the effect of noises generated in a condition where specific equipment such as an inverter is installed in a real plant. <P>SOLUTION: Power cables 22 of a motor system installed in a nuclear power generation plant includes: an electric current injection means 13 for injecting a common mode current of a high frequency; a signal wave generation device 14 for supplying a current of a high frequency to the electric current injection means in accordance with a predetermined pattern; a first current measurement means 15 for measuring a first common mode current flowing through the power cables 22; a second current measurement means 16 for measuring a second common mode current induced in a signal cable 4 of an instrumentation system in the plant by the first common mode current; and a transmissibility calculation device 17 for calculating the transmissibility of the common mode current on the basis of these measured current values. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor system and a measurement control system used in a nuclear power plant, and more particularly to an evaluation apparatus for evaluating the influence of noise. The present invention also relates to an evaluation method for evaluating the influence of noise.

  In recent nuclear power plants, the ratio of using an inverter as a power source for power equipment is increasing to improve operating efficiency. In addition, many uninterruptible power supply devices have been introduced to improve reliability. Such a power supply device generates a voltage having a desired amplitude and frequency by switching and smoothing and supplies the voltage to a load. In particular, recent switching elements can be switched at a very high speed in order to improve efficiency, and the resulting electromagnetic noise tends to have a large amplitude and a high frequency. For example, in an IGBT (Insulated Gate Bipolar Transistor) element, the switching time is shortened to about several hundred nanoseconds, and high frequency noise on the order of MHz is generated. In addition, it has been known that a contactor that has been conventionally used for on / off control of an electric device such as an electric valve generates a noise current having a high frequency and a large amplitude. With this background, the background level of electromagnetic noise in nuclear power plants has increased.

  On the other hand, means for measuring various weak signals are provided in the nuclear power plant. For example, a neutron instrumentation system may use a neutron source region monitor, an intermediate region monitor, an output region monitor to enable measurement of neutron flux and power in the reactor during the entire period when the reactor is loaded with fuel. Three types of neutron detectors are installed for handling very weak signals from these neutron detectors. In particular, among the nuclear instrumentation systems that monitor the power in the reactor, the neutron source area monitor used at the time of shutdown and startup such as during periodic inspections handles weak signals of 1 μA or less and is therefore affected by high-frequency noise. Cheap. Recently, an activation region neutron monitor in which a neutron source region monitor and an intermediate region monitor are integrated is used. Since such a nuclear instrumentation system outputs an indicated value to the reactor safety protection system, if noise is superimposed on the signal from the neutron detector, it may cause a false alarm or a false scrum. .

  Therefore, in order to identify the noise source and the intrusion location and avoid the influence on the reactor power control system, a plurality of current probes are installed in the metal conduit for storing the signal cable of the neutron detector. A noise monitoring system for a start-up area monitoring system is disclosed in which a current flowing through a conduit is detected by the current probe to detect the magnitude and position of electrical noise entering a stored coaxial cable. (For example, refer to Patent Document 1).

JP 2006-258729 A

  In recent years, work such as renewal of existing power supply facilities to high-efficiency inverters has been carried out in various plants. At that time, it is particularly important to confirm the influence of noise on this equipment before operating a new equipment such as an inverter, for example, in a nuclear power plant having a weak signal system such as a nuclear instrumentation system. .

  For this reason, as the simplest method, it is conceivable to actually operate equipment such as an inverter and measure the noise influence using, for example, a noise monitoring system disclosed in Patent Document 1.

  However, this noise monitoring system detects the current flowing through the metal conduit that houses the signal cable of the neutron detector of the start-up area monitoring system, and identifies the position and magnitude of the induction caused by electromagnetic noise. It is. Therefore, it is difficult to evaluate the influence of electromagnetic noise generated from a specific device such as an inverter on the measurement signal and control signal of the activation area monitor system in the actual plant by this noise monitoring system.

The reason is that in order to evaluate the influence of noise generated from a specific device on the target measurement system or control system, the noise must be identified from the observed waveform of the noise induced in the target measurement system or control system cable. This is because the influence of the device needs to be separated, but the influence cannot be separated for the following reason.
(1) There are various high-frequency noise sources in the plant, and they induce background noise in the measurement system and control system targeted, so it is difficult to distinguish from noise from specific equipment. . In order to distinguish it from other noise sources, it is easier to separate the effects of this specific device if it can be operated to generate noise that is larger than the original operating conditions, but such operation is usually not possible. Is possible.
(2) The noise waveform appearing in the target measurement system or control system is significantly different from the electromagnetic noise waveform originally generated by the specific device. FIG. 13 shows an example of a comparison between the noise current waveform A generated in the power cable of the inverter power supply and the noise current waveform B induced in the neutron instrumentation system cable laid in the vicinity. As described above, since the noise current induced in the measurement system and the control system normally propagates through the stray capacitance and the mutual inductance, high-frequency components among those generated by the noise source are easily transmitted.

  In other words, even if the waveform of noise generated in the target measurement system or control system is observed or the frequency characteristics are used, the contribution of electromagnetic noise from a specific device cannot be extracted.

  The present invention has been made on the basis of the above-mentioned matters, and the purpose thereof is an evaluation that can easily and beforehand evaluate the influence of noise generated when a specific device such as an inverter is installed in an actual plant. It is to provide an apparatus and an evaluation method.

  (1) In order to achieve the above object, the present invention provides an influence evaluation apparatus for an electric motor system for evaluating an influence of noise on an instrumentation system by an electric motor system installed in a nuclear power plant. A current injection means for injecting a high-frequency common mode current into the cable from the outside; a signal wave generator for supplying a high-frequency current to the current injection means according to a predetermined pattern; and a first current flowing in the power cable A first current measuring means for measuring a common mode current; and a first induced at least at one of a signal cable, a control cable, or a ground line of an instrumentation system in the nuclear power plant by the first common mode current. Second current measuring means for measuring two common mode currents, the first current measuring means and the second current measuring means. Each current value measured by the measuring means is inputted, and that a transmission rate calculation unit for calculating a transmission rate of the common mode current on the basis of these measured current.

  (2) In the above (1), preferably, the signal wave generating device outputs or stops the periodically changing current to the current injecting means and the signal generating means for generating the periodically changing current. Opening / closing means to perform, storage means for storing the output pattern of the periodically changing current, a first procedure for fetching the output pattern stored in the storage means, and an output pattern fetched in the first procedure And a control means for executing a second procedure for controlling the opening and closing of the opening and closing means, and outputting or stopping the periodically changing current to the current injecting means according to a predetermined pattern. And

  (3) In the above (1), preferably, the signal wave generating device outputs or stops the periodically changing current to the current injecting means and the signal generating means for generating the periodically changing current. Opening / closing means for performing, storage means for storing an output pattern in which the amplitude of the periodically changing current is changed at a plurality of levels, a first procedure for taking in the output pattern stored in the storage means, Control means for executing a second procedure for controlling the amplitude of the periodically changing current of the signal generating means and the opening and closing of the opening and closing means based on the output pattern taken in the procedure of 1, The output amplitude of the current supplied to the current injection means changes at a plurality of levels according to a predetermined pattern.

  (4) In the above (2) or (3), preferably, a sinusoidal current is used as the periodically changing current.

  (5) In any one of the above (1) to (4), preferably, the transmissibility calculating device includes a first and a second current measured by the first current measuring means and the second current measuring means. A band-pass filter to which two common mode current values are inputted, a first procedure for taking in the frequency of current supplied to the current injection means inputted from the signal wave generator, and taking in by the first procedure A control device that executes a second procedure for setting the pass band of each bandpass filter to the same value as the frequency of the signal, and a common mode current transfer rate based on the current value after passing through the bandpass filter. An arithmetic device for calculation is provided.

  (6) In any one of the above (1) to (5), preferably, the transmissibility calculating device is configured to input the input first and second common mode current values or the current after passing through the bandpass filter. Simultaneously with the input of the first and second common mode current values, the switching signal of the switching means, and the signal of the amplitude and frequency of the current supplied to the current injection means. A second procedure for correlating the first and second common mode current values inputted simultaneously and the state signal taken in the first procedure into data, and the second procedure From the control device that executes the third procedure for outputting and storing the data associated in the procedure to the storage device and the information stored in the storage device, the period during which the common mode current is stopped, Common mode current Output period determining means for determining a period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period during which the common mode current is output, and the common mode current is stopped. The first and second common mode current values during the period when the common mode current is output, and the first and second periods during the period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period during which the common mode current is output. And an arithmetic device that calculates a common mode current transmission rate based on the second common mode current value.

  (7) In the above (6), preferably, the transmissibility calculation device converts the input first and second common mode current values or the current value after passing through the band-pass filter into effective value data. The output value determining means is determined by the output period determining means based on the effective value calculation device, the storage device further storing the converted effective value data of the first and second common mode currents, and the information stored in the storage device. The first common mode current for each period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period during which the common mode current is stopped and the period in which the common mode current is output. Effective value calculation means for calculating the effective value data of the corresponding period of time and the effective value data of the second common mode current, and calculating the common mode current. The effective value of the second common mode current in the period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period being set, and the second common mode current in the period in which the output is stopped The effective value of the first common mode current in a period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period in which the common mode current is output, And an arithmetic unit that calculates a transmissibility of the common mode current by dividing by a value of a difference from an effective value of the first common mode current during a period in which the output is stopped.

  (8) In the above (6) or (7), it is preferable that the transmissibility calculating device includes first and second commons measured by the first current measuring unit and the second current measuring unit. A band-pass filter to which a mode current value is input, an effective value calculation device that converts first and second common mode current values that have passed through the band-pass filter into effective value data, and the converted first and second A storage device further storing effective value data of the second common mode current; a first procedure for calculating a frequency characteristic of the second common mode current during a period in which the common mode current is stopped; The second procedure for determining a frequency having a small current amplitude from the calculation result of the procedure in step 1 and the third procedure for transmitting the frequency value determined in the second procedure to the signal wave generator are executed. Background An analyzer, and the signal wave generator includes a storage unit that stores a frequency value transmitted from the transmissibility calculating device, and a first procedure that takes in the frequency value stored in the storage unit, Control means for executing a second procedure for controlling the frequency of the periodically changing current of the signal generating means based on the value of the frequency captured in the first procedure, and calculating the transfer rate It is assumed that a current having a frequency value transmitted from the apparatus is supplied to the current injector.

  (9) In order to achieve the above object, the present invention provides a motor system influence evaluation method for evaluating the influence of noise on an instrumentation system by an electric motor system installed in a nuclear power plant. A step of injecting a high-frequency common mode current into the cable according to a predetermined pattern from the outside by a current injection means; and a first common mode flowing through the power cable by a first current measurement means provided in the power cable A current measuring step and a second current measuring means provided in at least one of a signal cable, a control cable or a ground line of an instrumentation system in the nuclear power plant, induced by the first common mode current. Step of measuring the second common mode current and the transmissibility calculation device What shall comprising calculating a transmission rate of the common mode current on the basis of the first common mode current value and the second common mode current.

  According to the present invention, according to a known pattern, data of a period during which noise is applied to a power cable and data during a period during which noise is not applied can be obtained separately, and the influence of noise applied from the difference between the two can be obtained. Only can be extracted. This makes it possible to extract the contribution of electromagnetic noise from a specific device. As a result, the influence of equipment such as an inverter on a weak signal system such as a nuclear instrumentation system can be easily evaluated with simple equipment in advance.

  Embodiments of an influence evaluation apparatus for an in-plant electric motor system according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a system configuration including an embodiment of an influence evaluation apparatus for an in-plant electric motor system according to the present invention. In FIG. 1, in a nuclear power plant, a reactor pressure vessel 1, a nuclear instrumentation tube 2 inserted into the reactor pressure vessel 1, and a nuclear instrumentation tube 2 are accommodated in the reactor pressure vessel 1. A neutron detector 3 that generates a weak current by thermal neutrons, a nuclear instrumentation cable 4 that transmits a weak current signal from the neutron detector 3 to the preamplifier 5, and an output signal of the preamplifier 5 is the nuclear instrumentation cable 4 A nuclear instrumentation system comprising a neutron monitoring device 6 transmitted by the Thus, the nuclear instrumentation system measures neutrons in the reactor pressure vessel 1 using weak signals. Therefore, the neutron monitoring device 6 is grounded to the grounding trunk line 8 by the grounding wire 7 at one point for the purpose of making it less susceptible to noise from other power equipment and the like.

  In the nuclear power plant, an electric motor system including an electric motor 9, an output filter 10, and an inverter power source 11 is provided. In this electric motor system, the electric motor 9 and the inverter power supply 11 are connected to the grounding trunk line 8 by the ground lines 7 and 7, respectively. The power cable 22 connecting the electric motor 9 and the inverter power supply 11, the grounding trunk line 8, A large loop is formed by the ground lines 7 and 7. For example, a high-frequency noise current generated by the above-described inverter power supply flows in this loop as a common mode current (first common mode current). In the present invention, the first common mode current means a noise current flowing in a loop formed by the power cable 22 connecting the electric motor 9 and the inverter power supply 11, the ground trunk line 8, and the ground lines 7 and 7. .

  The first common mode current is propagated to the nuclear instrumentation system via the electromagnetic induction between the cables or the common ground trunk line, but a small amount is transmitted to the nuclear instrumentation system. ). In the present invention, the second common mode current is generated by the first common mode current, and is a loop configured between the signal cable or control cable of the instrumentation system, the ground line 7, and the ground trunk line 8. It means the flowing noise current.

  The influence evaluation device 12 of the present invention includes a current injector 13 as current injection means for injecting a first common mode current, which is a simulated noise current, into a power cable 22 of an electric motor, and a high-frequency noise current in the current injector 13. , A first current measuring instrument 15 as a first current measuring means for measuring a first common mode current injected into the power cable 22 by the current injector 13, A second current measuring device 16 as a second current measuring means for measuring a second common mode current induced in the nuclear instrumentation cable 4 or the ground line 7 by the common mode current, and the first and second And a transmissibility calculation device 17 that calculates the transmissibility of noise based on the measured value of the common mode current.

  The current injector 13 injects a high-frequency noise current applied from the signal wave generator 14 into the power cable 22 and is generally formed in a ring shape. Specifically, the probe body is made of ferrite and becomes a ring shape when coupled, a coil (not shown) wound around the probe body, and a lead cable connecting the coil and the signal wave generator 14. The power cable is configured so that the power cable 22 is inserted into the probe body. Here, the current injector 13 injects a high-frequency noise current corresponding to the applied high-frequency signal into the power cable 22 by electromagnetic induction.

  The first and second current measuring devices 15 and 16 measure the current of the power cable 22, the nuclear instrumentation cable 4, or the ground wire 7 described above, and are formed in a substantially ring shape. Specifically, the probe body is made of ferrite and becomes a ring shape when coupled, a coil (not shown) wound around the probe body, and a lead cable connecting the coil and the transmissivity calculation device 17 It is comprised and is arrange | positioned at each cable 4 and 22 so that each cable 4 and 22 mentioned above may penetrate the probe main body, respectively.

  FIG. 2 is a functional block diagram of the signal wave generator 14 constituting one embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. 2, the same reference numerals as those shown in FIG. 1 denote the same parts. The signal wave generator 14 includes a signal generator 18 as a signal generator that generates a periodically changing signal wave such as a sine wave having an arbitrary frequency, and the signal wave generated by the signal generator 18 to the outside. An SSR (solid state relay) 23 as an opening / closing means for performing output or stop by opening / closing thereof, a pattern for stopping or outputting a signal wave, an input / output interface 20 for inputting a frequency and amplitude of the signal wave in advance, and the input result The first storage device 21 as storage means for storing and the data stored in the storage device 21 are taken in, the SSR 23 is opened and closed based on this data, and the amplitude and frequency of the signal wave generated by the signal generator 18 And a control device 19 as a control means for controlling the above.

  In order to apply the signal wave generated by the signal wave generator 14 to the current injector 13, the output terminal of the SSR 23 and the current injector 13 are connected by a lead cable (see FIG. 1). In addition, the frequency and amplitude signals of the noise current applied to the open / close of the SSR 23 and the current injector 13 are transmitted from the control device 19 to the transmissibility calculation device 17 via a transmission path such as serial communication, for example. .

  FIG. 3 is a functional block diagram of the transmissibility calculation device 17 constituting an embodiment of the influence evaluation device for an in-plant electric motor system of the present invention. In FIG. 3, the same reference numerals as those shown in FIG. The transmissibility calculation device 17 receives the measured first and second common mode currents, and passes bandpass filters 24 and 24 that pass signals in a set frequency band, and the current value that has passed through the bandpass filter. A / D conversion circuits 26 and 26 for converting to digital values, RMS value calculating devices 27 and 27 for converting the digital values to RMS value data, and the noise current input through the passbands of the bandpass filters 24 and 24 At this time, the current value data passing through the band-pass filters 24 and 24 is either SSR 23 open (current stop) or closed (current output) data, and the frequency of the noise current. And the control device 25 for transmitting the amplitude value to the second storage device 28, the SSR open / close data and the frequency / amplitude of the noise current together with the effective value data. A second storage device 28 in which the data is stored, and an arithmetic circuit 29 as an arithmetic device for calculating the transmissibility of the first and second common mode currents based on the information stored in the second storage device 28 And a third storage device 30 for storing the calculated transmission rate and the frequency / amplitude value of each common mode current, and the frequency / amplitude value and transmission rate stored in the third storage device 30 as one set. And a display device 31 for displaying.

  Based on the information stored in the second storage device 28, the arithmetic circuit 29 outputs a period in which the current is stopped, a period in which the current is output, and a current output from the measured value of the first common mode current. Output period determining means for determining a period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period being set, and for each period determined by the output period determining means, the first and second Effective value calculation means for calculating the effective value of the common mode current by averaging the effective value data of the corresponding period.

  In order to capture the measured values of the first and second common mode currents into the transmissibility calculating device 17, the output ends of the first and second current measuring devices 15 and 16 and the transmissibility calculating device 17 are connected by a lead cable. Each is connected (see FIG. 1). In addition, the signal of the frequency and amplitude of the noise current applied to the opening / closing of the SSR 23 and the current injector 13 is input from the signal wave generator 14 to the controller 25.

  Next, operation | movement of one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention mentioned above is demonstrated using FIG. 1 thru | or FIG.

  First, the user inputs an output stop pattern, a frequency and an amplitude pattern of noise current injected into the power cable 22 via the input / output interface 20 of the signal wave generator 14 shown in FIG. This input result is stored in the first storage device 21 of the signal wave generator 14.

  Next, in response to a read command from the control device 19 of the signal wave generator 14, the output stop pattern of the noise current injected into the power cable 22 and the frequency and amplitude pattern are taken into the control device 19. The control device 19 sets the frequency and amplitude of the noise current to be generated by the signal generator 18 to a value obtained, and controls the opening and closing of the SSR 23 so as to obtain an output stop pattern of the taken noise current. The noise current output from the signal wave generator 14 is applied to the current injector 13. As a result, a common mode current according to a predetermined pattern can be injected into the power cable 22. In addition, the control device 19 of the signal wave generator 14 outputs an open / close signal to the SSR and a frequency and amplitude signal to the transmissibility calculator 17.

  When a current is applied to the current injector 13 by the signal wave generator 14, first and second common mode currents are respectively generated in the power cable 22 and the nuclear instrumentation cable 4 of the electric motor 9 shown in FIG. 1. The two common mode currents are measured by the first and second current measuring devices 15 and 16, and these measured current values are input to the transmissibility calculating device output device 17.

  In the transmissibility calculation device 17, as shown in FIG. 3, these current measurement values are input to the band-pass filters 24 and 24, respectively. At the same time, the controller 25 inputs the open / close signal to the SSR from the signal wave generator 14 and the data of the frequency and amplitude signals. The control device 25 sets the passband of the bandpass filters 24, 24 to the frequency transmitted from the signal wave generator 14, and at this time, the current value data passing through the bandpass filters 24, 24 is Whether the data is open (current stop) or closed (current output) of the SSR 23 and the frequency and amplitude values of the current applied to the current injector 13 are stored in the second storage device 28.

  Each current value that has passed through the band-pass filters 24, 24 is converted into a digital value by the A / D conversion circuits 26, 26, and converted into effective value data by the effective value arithmetic units 27, 27. This effective value data is stored in the second storage device 28 together with the opening / closing data and frequency / amplitude data of the SSR 23.

  The arithmetic circuit 29 calculates the transmission rates of the first and second common mode currents using the effective value calculation means and the like based on the information stored in the second storage device 28. Specifically, out of the second common mode current stored in the second storage device 28, the frequency and amplitude are the same, and two data when the SSR 23 is open and closed are extracted as a pair. Then, by taking the difference between the effective value data when the SSR 23 is closed and the effective value data when the SSR 23 is open, a substantial influence on the second common mode current by the first common mode current (after correcting this) Of the second common mode current). Similarly, a difference between two effective value data of the first common mode current having the same frequency and amplitude and when the SSR 23 is open and closed is calculated, and the substantial first common mode current is calculated. (This is called the corrected first common mode current effective value).

  Then, the transmissibility is calculated by dividing the corrected second common mode current effective value by the corrected first common mode current effective value. The calculated transmission rate is stored in the third storage device 30 together with the frequency and the amplitude value.

  The display device 31 displays the frequency, amplitude value, and transmission rate stored in the third storage device 30 as one set.

  Here, the influence of the background is excluded by subtracting the effective value of the common mode current when the SSR is opened from the effective value of the common mode current when the SSR 23 is closed, but the background noise is the original effect. Another background removal method may be used in order to improve evaluation accuracy, such as a method of taking the square root of the square of the effective value assuming that it is independent.

  According to an embodiment of the influence evaluation apparatus for an in-plant electric motor system of the present invention, according to a known pattern, the data of the period during which noise is applied to the power cable and the data during which it is not applied can be obtained separately. It is possible to extract only the influence of the applied noise from the difference between the two.

  This makes it possible to extract the contribution of electromagnetic noise from a specific device. As a result, the influence of equipment such as an inverter on a weak signal system such as a nuclear instrumentation system can be grasped in advance.

  Also, rather than actually operating a specific device and applying noise, the signal wave generator is connected to the same path as the propagation path of common mode noise that affects the measurement system and control system targeted by the device. By applying simulated common mode noise, equivalent noise can be generated with much smaller power than when actually operating the device.

  Furthermore, it becomes possible to generate noise larger than that of the actual machine, and it becomes possible to distinguish from other noise sources, so that it is easy to extract the influence of noise of this specific device. From the above, it is possible to easily evaluate the influence of noise that the motor system has on the measurement system, the control system, and the like with simple equipment.

  Next, the types of current waveforms applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for an in-plant electric motor system according to the present invention and the effects thereof will be described with reference to FIGS.

  FIG. 4 is an explanatory diagram of a first example of a current waveform applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. In FIG. 4, the signal output from the signal generator 18 is a sine wave having a frequency of 100 kHz (the upper waveform in FIG. 4). After this sine wave having a constant amplitude is output for 100 microseconds by the opening / closing operation of the SSR 23, Repeat a pattern that stops for 100 microseconds. The control device 19 transmits a sine wave frequency of 100 kHz, an amplitude of 1.0 (relative value), and an opening / closing signal value (1.0 or 0.0) at the time (lower signal in FIG. 4) to the transmissibility calculating device 17. Thus, by transmitting a sine wave signal, it is possible to calculate a common mode current transfer rate limited to a single frequency.

  FIG. 5 is an explanatory diagram of a second example of a current waveform applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. FIG. 5 shows another example of the current waveform applied from the signal wave generator 14. The signal output from the signal generator 18 has the same frequency as 100 kHz (the upper waveform in FIG. 5), but the amplitude is as shown in the amplitude signal in FIG. 5 (lower signal in FIG. 5). Furthermore, out of 100 microseconds when the open / close signal (the middle signal in FIG. 5) is 1.0, the amplitude signal is 0.5 (relative value) for the first 50 microseconds, and 1.0 (relative value) for the subsequent 50 microseconds. Change. In this way, by changing a plurality of applied current amplitudes, it is possible to improve the estimation accuracy of the noise influence due to the smaller or larger amplitudes.

  FIG. 6 is an explanatory diagram of a third example of a current waveform applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. FIG. 6 shows an example in which a rectangular wave (the upper waveform in FIG. 6) is used as the current waveform applied from the signal wave generator 14. The same period, amplitude and SSR23 opening / closing timing (lower signal in FIG. 6) as in the first example are used, but a wide frequency component is included by using a rectangular wave as a waveform generated from the signal generator 18. Therefore, it is possible to grasp the frequency component having a relatively large influence and its degree of influence relatively easily.

  FIG. 7 is an explanatory diagram of a fourth example of the current waveform applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. FIG. 7 shows an example in which a noise waveform actually generated by an electric motor is sampled and used as a current waveform applied from the signal wave generator 14 (the upper waveform in FIG. 7). In the signal wave generator 14, instead of the signal generator 18, for example, a function generator capable of storing and outputting specific waveform data can be used. By changing the amplitude, there is an advantage that the influence when the output is increased can be directly evaluated.

  FIG. 8 is an explanatory diagram of a fifth example of the current waveform applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. FIG. 8 shows a pulse wave with a narrow interval of about 0.5 microseconds at the time when the amplitude level of the current changes (or when the output / stop is switched) with respect to the current waveform of the second example shown in FIG. This is an example in which the upper waveform in FIG. There is a time delay until the applied current is received from the signal wave generator 14 through the power cable 22 of the electric motor, the nuclear instrumentation cable 4 and the second current measuring device 16 by the transmissibility calculation device 17. Precisely determining the period corresponding to each amplitude level based on the reception time of the pulse wave is effective for improving the calculation accuracy of the transmission rate.

  FIG. 9 is a designation table for sweeping the frequency of the current waveform applied to the current injector 13 used in the embodiment of the influence evaluation apparatus for the in-plant electric motor system of the present invention. The data shown in FIG. 9 is stored in the first storage device 21 of the signal wave generator 14 shown in FIG. The control device 19 is No. 1 is read sequentially from 10 kHz, and the frequency of the signal generator 18 is sequentially changed to a designated value. No. After the application of 500 5 MHz sine wave current is completed, the controller 19 completes the measurement by setting the amplitude signal to the signal generator 18 to 0.0. Thereby, the frequency designated on the display device 31 of the transmissibility calculation device 17 shown in FIG. 3 and the transmissibility of the common mode current at that time are displayed for each frequency. That is, the frequency characteristic with respect to the common mode current transfer rate can be measured. As a result, an effective countermeasure corresponding to the noise frequency can be easily performed.

  Next, a second embodiment of the influence evaluation apparatus for an in-plant electric motor system according to the present invention will be described with reference to FIG. FIG. 10 is a functional block diagram of the transmissibility calculating device 17 constituting the second embodiment of the influence evaluation device for the in-plant electric motor system of the present invention. In the following description, the same reference numerals are given to the same components as those in the embodiment of the present invention described above, and the description of the portions is omitted.

  In FIG. 10, the transmissibility calculating device 17 sequentially changes the passbands of the background mode switch 32 for designating the background mode and the bandpass filters 24 and 24 to a predetermined frequency, and converts the background mode signal to A background analysis unit 33 that transmits to the arithmetic circuit 29; an arithmetic circuit 29 that stores the effective value of the second common mode current for each frequency in the third storage device 30; a second common mode current for each frequency; And the display device 31 that displays the frequency at which the second common mode current value is minimized, the input / output interface 35 that specifies the frequency value of the noise current to be applied, and the signal wave generator 14 that transmits the specified frequency value. And a frequency designation device 34 for transmitting to the network.

  Next, the operation of the above-described second embodiment of the influence evaluation apparatus for an in-plant electric motor system according to the present invention will be described with reference to FIG. 1, FIG. 2, and FIG.

  First, the user designates the background mode via the background mode switch 32. When the background mode is designated, the background analysis unit 33 built in the control device 25 sequentially changes the passbands of the bandpass filters 24 and 24 according to the predetermined lower limit, upper limit, and interval. At this time, the value of the passing frequency of the current value data passing through the band pass filters 24 and 24 is stored in the second storage device 28. At the same time, the background analysis unit 33 transmits a background mode signal to the arithmetic circuit 29.

  Next, the arithmetic circuit 29 that has received the background mode signal extracts the information stored in the second storage device 28 and stores the effective value of the second common mode current for each frequency in the third storage device 30. To do.

  The display device 31 displays the frequency at which the second common mode current value is minimized in addition to the second common mode current for each frequency from the data stored in the third storage device 30.

  The user selects a frequency to be tested from the displayed results, and inputs a frequency value of a noise current to be applied via the input / output interface 35. This input result is input to the frequency specifying device 34, and the frequency specifying device 34 transmits the specified frequency value to the signal wave generating device 14.

  The signal wave generator 14 receives the frequency at the input / output interface 20 in FIG. 2 and stores this frequency in the first storage device 21. The control device 19 applies the current of the specified frequency to the current injector 13 by taking in and controlling the frequency value from the first storage device 21.

  According to the second embodiment of the influence evaluation apparatus for an in-plant electric motor system of the present invention described above, a frequency band with a low background noise level can be grasped by performing background analysis. As a result, a common mode current having a frequency selected from these frequency bands can be injected into the power cable. That is, the impact evaluation can be performed with noise that can be easily distinguished from noise from other noise sources (background noise). Since the transmissibility of the common mode current can be calculated in a frequency band in which the influence of the background noise is reduced, the evaluation accuracy of the transmissibility calculation device 17 can be improved.

  Next, a third embodiment of the influence evaluation apparatus for an in-plant electric motor system of the present invention will be described with reference to FIG. FIG. 11 is a functional block diagram of the transmissibility calculating device 17 constituting the third embodiment of the influence evaluation device for the in-plant electric motor system of the present invention. In the following description, the same components as those of the above-described embodiment of the present invention are denoted by the same reference numerals, and description of the portions is omitted.

  In FIG. 11, the transmissibility calculating device 17 includes a fourth storage device 36 storing the upper limit values of the first and second common mode currents separately evaluated in advance, and the calculated amplitude setting value as a third value. An arithmetic circuit 29 that stores in the storage device 31 and transmits to the amplitude signal generator 37 and an amplitude signal generator 37 that transmits the received amplitude signal to the signal wave generator 14 are provided.

  Next, the operation of the third embodiment of the influence evaluation apparatus for an in-plant electric motor system of the present invention described above will be described with reference to FIGS.

  First, in order not to affect the nuclear instrumentation system, the upper limit value of the second common mode current that has been separately evaluated is stored in the fourth storage device 36. Here, the upper limit value of the second common mode current that does not affect the nuclear instrumentation system is, for example, a second value that does not substantially affect the indication value of the nuclear instrumentation system such as the occurrence of a false alarm or an erroneous scram. Means the maximum value of common mode current.

Next, the arithmetic circuit 29 obtains the ratio of the effective values of the first common mode current and the second common mode current and takes in the upper limit value of the second common mode current from the fourth storage device 36. The amplitude set value L is calculated by multiplying the upper limit value of the second common mode current by the ratio of the effective value. The amplitude setting value L is obtained by the following equation.
L = (I _C1 / I _C2 ) × I _C2max (1)
Here, I _C1 is a first common mode current value, I _C2 is a second common mode current value, and I _C2max is a second common mode current upper limit value.

  In addition, the arithmetic circuit 29 stores the calculated amplitude set value L in the third storage device 30 and displays it on the display device 31, and transmits it to the amplitude signal generator 37.

  The amplitude signal generator 37 that has received the amplitude signal transmits the amplitude signal to the signal wave generator 14. The signal wave generator 14 receives the amplitude signal at the input / output interface 20 in FIG. 2 and stores this amplitude in the first storage device 21. The control device 19 takes in the amplitude value from the first storage device 21 and controls it to apply a current having a specified amplitude to the current injector 13.

  Further, in the transmission rate calculation device 17, the maximum generated current that has been separately evaluated in advance according to the electric motor, that is, the upper limit value for the first common mode current is stored in the fourth storage device 36.

Next, the arithmetic circuit 29 determines the effective value of the first common mode current, the effective value of the second common mode current, the upper limit value of the second common mode current captured from the fourth storage device 36, and the first value. The second common mode current when the first common mode current becomes the upper limit value, that is, the maximum noise influence is calculated using the upper limit value of the common mode current of 1. Further, a ratio of the second common mode current to the second common mode current upper limit value, that is, a noise margin is calculated. The maximum noise influence NE and the noise margin NM are obtained by the following equations.
NE = (I _C2 / I _C1 ) × I _C1max (2)
NM = NE / I _C2max (3)
Here, I _C1 is the first common mode current value, I _C2 is the second common mode current value, I _C1max is the first common mode current upper limit value, and I _C2max is the second common mode current upper limit value. .

  The arithmetic circuit 29 stores the calculated maximum noise influence NE and noise margin NM in the third storage device 30 and displays them on the display device 31.

  According to the third embodiment of the influence evaluation apparatus for an in-plant electric motor system of the present invention, the signal wave is within a range that does not substantially affect the indication value of the nuclear instrumentation system such as the occurrence of a false alarm or a false scrum. The output current value of the generator 14 can be set as large as possible. This makes it possible to accurately evaluate the influence of noise.

Further, the following values can be accurately grasped from the display of the display device 31. That is, the maximum current value of the signal wave generator 14 that can be applied within a range that does not substantially affect the instruction value of the nuclear instrumentation system can be grasped by the amplitude setting value L displayed on the display device 31.
Further, when the maximum noise current assumed by the actual operation of the device flows due to the maximum noise influence NE displayed on the display device 31, the value of the second common mode current generated in the nuclear instrumentation system can be grasped.
Furthermore, when the maximum noise current assumed by the operation of the actual device flows due to the noise margin NM displayed on the display device 31, the second common mode current generated in the nuclear instrumentation system is an instruction of the nuclear instrumentation system. It is possible to grasp the margin until the value has a substantial effect such as the occurrence of a false alarm or a false scrum.

  Furthermore, since the calculated amplitude setting value L, maximum noise influence NE, and noise margin NM are displayed on the display device 31, the evaluation after actual measurement can be seen on the spot. Therefore, even if measurement for evaluation is required again, it can be carried out easily, safely and quickly. Further, from this, for example, the period required for noise countermeasures can be shortened.

  Next, a fourth embodiment of the influence evaluation apparatus for an in-plant electric motor system according to the present invention will be described with reference to FIG. FIG. 12: is a conceptual diagram which shows the system configuration | structure provided with 4th Embodiment of the impact evaluation apparatus of the in-plant electric motor system of this invention. In the following description, the same constituent elements as those of the embodiment of the present invention described above are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, wireless transmission terminals 38 and 38 are connected to the first and second current measuring devices 15 and 16, respectively. In addition, a wireless reception terminal 39 is connected to the transmission rate calculation device 17.

  In the noise influence evaluation apparatus 12 configured as described above, for example, a position where the first common mode current is measured and a position where the second common mode current is measured are extremely separated from each other in the plant. Even when it is impossible or difficult to lay the cable, the noise influence evaluation device 12 can be operated because the signal can be exchanged.

  In addition, in this invention, although demonstrated in the electric motor system provided with the inverter power supply, it is not restricted to this. Any electric motor system in which a loop is formed by a power cable, a ground line, and a ground trunk line may be used.

It is a conceptual diagram which shows the system configuration | structure provided with one Embodiment of the impact evaluation apparatus of the in-plant electric motor system of this invention. It is a functional block diagram of the signal wave generator 14 which comprises one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is a functional block diagram of the transmission rate calculation apparatus 17 which comprises one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is explanatory drawing of the 1st example of the current waveform applied to the current injector 13 used for one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is explanatory drawing of the 2nd example of the current waveform applied to the current injector 13 used for one embodiment of the influence evaluation apparatus of the in-plant electric motor system of the present invention. It is explanatory drawing of the 3rd example of the current waveform applied to the current injector 13 used for one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is explanatory drawing of the 4th example of the current waveform applied to the current injector 13 used for one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is explanatory drawing of the 5th example of the current waveform applied to the current injector 13 used for one embodiment of the influence evaluation apparatus of the in-plant electric motor system of the present invention. It is a designation | designated table | surface figure for sweeping the frequency of the current waveform applied to the current injector 13 used for one Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is a functional block diagram of the transmission rate calculation apparatus 17 which comprises 2nd Embodiment of the impact evaluation apparatus of the in-plant electric motor system of this invention. It is a functional block diagram of the transmission rate calculation apparatus 17 which comprises 3rd Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is a conceptual diagram which shows the system configuration | structure provided with 4th Embodiment of the influence evaluation apparatus of the in-plant electric motor system of this invention. It is explanatory drawing which shows an example of the comparison with the noise current waveform which arose in the power cable of the inverter power supply, and the noise current waveform induced | guided | derived to the neutron instrumentation system cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 2 Nuclear instrumentation tube 3 Neutron detector 4 Nuclear instrumentation cable 5 Preamplifier 6 Neutron monitoring device 7 Grounding wire 8 Grounding trunk 9 Motor 10 Output filter 11 Inverter power supply 12 Influence evaluation device 13 Current injector 14 Signal wave Generating device 15 First current measuring device 16 Second current measuring device 17 Transmission rate calculating device 22 Power cable 23 SSR (solid state relay)
24 Bandpass Filter 27 RMS Value Calculation Device 33 Background Analysis Unit

Claims (9)

In the motor system impact assessment device that evaluates the impact of noise on the instrumentation system by the motor system installed in the nuclear power plant,
Current injection means for injecting a high-frequency common mode current from the outside into the power cable of the motor system;
A signal wave generator for supplying a high frequency current to the current injection means according to a predetermined pattern;
First current measuring means for measuring a first common mode current flowing in the power cable;
Second current measuring means for measuring a second common mode current induced in at least one position of a signal cable, a control cable or a ground line of an instrumentation system in the nuclear power plant by the first common mode current When,
A transmissibility calculating device for inputting each current value measured by the first current measuring means and the second current measuring means and calculating a transmissivity of a common mode current based on the measured current values; An impact evaluation apparatus for an electric motor system, comprising: In the electric motor system influence evaluation apparatus according to claim 1,
The signal wave generator is
Signal generating means for generating a periodically changing current;
Opening / closing means for outputting or stopping the periodically changing current to the current injection means;
Storage means for storing an output pattern of the periodically changing current;
A first procedure for capturing an output pattern stored in the storage means;
Control means for executing, based on the output pattern captured in the first procedure, a second procedure for controlling the opening and closing of the opening and closing means,
An apparatus for evaluating the influence of an electric motor system, wherein the periodically changing current is output to or stopped from the current injection means in accordance with a predetermined pattern. In the electric motor system influence evaluation apparatus according to claim 1,
The signal wave generator is
Signal generating means for generating a periodically changing current;
Opening / closing means for outputting or stopping the periodically changing current to the current injection means;
Storage means for storing an output pattern in which the amplitude of the periodically changing current is changed at a plurality of levels;
A first procedure for capturing an output pattern stored in the storage means;
Control means for executing a second procedure for controlling the amplitude of the periodically changing current of the signal generating means and the opening and closing of the opening and closing means based on the output pattern captured in the first procedure; Prepared,
The apparatus for evaluating the influence of an electric motor system, wherein the amplitude at the time of outputting the current supplied to the current injection means changes at a plurality of levels according to a predetermined pattern. In the electric motor system influence evaluation apparatus according to claim 2 or 3,
An apparatus for evaluating the influence of an electric motor system, wherein a sinusoidal current is used as the periodically changing current. In the electric motor system influence evaluation apparatus according to any one of claims 1 to 4,
The transmission rate calculation device includes:
A band pass filter to which the first and second common mode current values measured by the first current measuring means and the second current measuring means are input;
A first procedure for capturing the frequency of the current supplied to the current injection means input from the signal wave generator, and the passband of each bandpass filter to the same value as the frequency captured in the first procedure A control device for executing a second procedure for setting
An influence evaluation apparatus for an electric motor system, comprising: an arithmetic unit that calculates a common mode current transfer rate based on a current value after passing through the band pass filter. In the electric motor system influence evaluation apparatus according to any one of claims 1 to 5,
The transmission rate calculation device includes:
A storage device for storing the input first and second common mode current values or the current value after passing through the band-pass filter;
At the same time as the input of the first and second common mode current values, the first procedure for taking in the open / close signal of the open / close means and the signal of the amplitude and frequency of the current supplied to the current injection means is simultaneously input. A second procedure for associating the first and second common mode current values and the state signal captured in the first procedure into data, and storing the data associated in the second procedure A control device that executes a third procedure that is output to the device and stored;
From the information stored in the storage device, the amplitude has a plurality of levels in the period in which the common mode current is stopped, the period in which the common mode current is output, and the period in which the common mode current is output. An output period determining means for determining a period corresponding to each amplitude when changing;
Corresponding to the first and second common mode current values during the period when the common mode current is stopped and each amplitude when the amplitude changes at a plurality of levels during the period when the common mode current is output An influence evaluation device for an electric motor system, comprising: an arithmetic device that calculates a transmission rate of a common mode current based on the first and second common mode current values of a period. In the electric motor system influence evaluation apparatus according to claim 6,
The transmission rate calculation device includes:
An effective value calculation device for converting the input first and second common mode current values or the current value after passing through the band-pass filter into effective value data;
A storage device further storing the converted effective value data of the first and second common mode currents;
When the amplitude changes at a plurality of levels during the period when the common mode current determined by the output period determining means is stopped and during the period when the common mode current is output from the information stored in the storage device For each period corresponding to each amplitude, an effective value calculation is performed by averaging the effective value data of the corresponding period with the effective value of the first common mode current and the effective value of the second common mode current. Means,
The effective value of the second common mode current in the period corresponding to each amplitude when the amplitude changes at a plurality of levels in the period in which the common mode current is output, and the period in which the output is stopped The difference between the effective value of the second common mode current and the first common mode in a period corresponding to each amplitude when the amplitude changes at a plurality of levels during the period in which the common mode current is output. An arithmetic unit that calculates the transmissibility of the common mode current by dividing by the value of the difference between the effective value of the current and the effective value of the first common mode current during the period when the output is stopped; An impact evaluation apparatus for an electric motor system, comprising: In the electric motor system influence evaluation apparatus according to claim 6 or 7,
The transmission rate calculation device includes:
A band pass filter to which the first and second common mode current values measured by the first current measuring means and the second current measuring means are input;
An effective value calculation device that converts the first and second common mode current values that have passed through the bandpass filter into effective value data;
A storage device further storing the converted effective value data of the first and second common mode currents;
A first procedure for calculating a frequency characteristic of the second common mode current during a period when the common mode current is stopped, and a second procedure for determining a frequency having a small current amplitude from the calculation result of the first procedure. And a background analysis unit for executing a third procedure for transmitting the frequency value determined in the second procedure to the signal wave generator,
The signal wave generator is
Storage means for storing a frequency value transmitted from the transmission rate calculation device;
A first procedure for capturing a frequency value stored in the storage means;
Control means for executing a second procedure for controlling the frequency of the periodically changing current of the signal generating means based on the value of the frequency captured in the first procedure,
An influence evaluation apparatus for an electric motor system, wherein a current having a frequency value transmitted from the transmission rate calculation apparatus is supplied to the current injector. In the motor system impact assessment method for evaluating the impact of noise on the instrumentation system by the motor system installed in the nuclear power plant,
Injecting a high-frequency common mode current into a power cable of the motor system according to a predetermined pattern from the outside by a current injection means;
Measuring a first common mode current flowing in the power cable by first current measuring means provided in the power cable;
Second common mode current induced by the first common mode current by second current measuring means provided at least at one position of a signal cable, a control cable or a ground line of an instrumentation system in the nuclear power plant. Measuring steps,
A method for evaluating the influence of an electric motor system, comprising: a step of calculating a transmissibility of a common mode current based on the first common mode current value and the second common mode current value by a transmissibility calculating device. .

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