JP2005345335A - Voltage measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage measuring device capable of detecting surely a surge voltage. <P>SOLUTION: This device is equipped with a voltage measuring part 2 having a low-pass filter 21 for removing a high frequency component in an alternating-current signal S0, an A/D converter 22 for sampling an alternating-current signal S1 passing the low-pass filter 21 and outputting data Dw for voltage operation, and a measuring circuit 23 for measuring the voltage of the alternating-current signal S0 based on the data Dw for voltage operation; and a surge voltage detecting measuring part 3 having an A/D converter 31 for sampling the alternating-current signal S0 and outputting data D0 for surge voltage operation, a high-pass filter 32 for generating surge voltage data Dn corresponding to the surge voltage from the data D0 for surge voltage operation, and a detecting measuring circuit 33 for comparing the voltage of the surge voltage shown by the surge voltage data Dn with a reference value and outputting a pulse signal Sp when the voltage of the surge voltage exceeds the reference value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a voltage measuring device that measures the voltage of an input signal.

  As this type of voltage measuring apparatus, the applicant discloses a voltage measuring device for a power line in Japanese Patent Application Laid-Open No. 2002-90397. This voltage measuring instrument includes a low-speed A / D conversion circuit, a high-speed A / D conversion circuit, a control unit, and a memory, and is configured to be able to simultaneously measure a voltage waveform of a power line and a sudden impulse waveform (surge voltage). ing. In this voltage measuring device, a low-speed A / D conversion circuit digitally converts an analog voltage waveform, which is input from a commercial power supply line and from which noise has been removed by a low-pass filter, at a slow sampling period of 256 or 512 per wave. At this time, the control unit writes the low-speed conversion data digitally converted by the low-speed A / D conversion circuit to the first memory area in the memory.

On the other hand, in parallel with the digital conversion by the low-speed A / D conversion circuit, the high-speed A / D conversion circuit digitally converts the voltage waveform with a high-speed sampling clock of about 2 MHz, for example. At this time, each time the high speed conversion data output from the high speed A / D conversion circuit is input, the control unit calculates the difference between the high speed conversion data and the low speed conversion data output from the low speed A / D conversion circuit. Then, when this difference exceeds a predetermined trigger level, the generation of an impulse waveform is detected. At this time, the control unit writes the high-speed conversion data before and after the point in time when it is determined that the impulse waveform is generated in the second memory area in the memory. Thereby, the voltage waveform and impulse waveform of a power line are measured simultaneously.
JP 2002-90397 A (page 3-4, FIG. 3-4)

  However, this voltage measuring instrument has the following problems to be improved. That is, in this voltage measuring device, the impulse waveform (surge voltage) is calculated by calculating the difference between the low-speed conversion data output from the low-speed A / D conversion circuit and the high-speed conversion data output from the high-speed A / D conversion circuit. Detected. However, when the surge voltage that could not be removed by the low-pass filter connected to the low-speed A / D conversion circuit is superimposed on the low-speed conversion data, the superposed amount is the difference value between the low-speed conversion data and the high-speed conversion data. Is included as a measurement error. Therefore, there is a possibility that erroneous detection such as detection failure of the surge voltage may occur due to this measurement error, and it is preferable to improve this. Further, based on the calculated difference value, a period in which the difference value exceeds a predetermined trigger level is defined as a surge voltage signal length (pulse width), and a period in which the difference value exceeds a predetermined trigger level. If the maximum value of the difference value is the peak value of the surge voltage, the measurement error is included in the signal length of the surge voltage and the peak value of the surge voltage due to the measurement error included in the difference value. It is preferable to improve.

  This invention is made | formed in view of this subject, and it aims at providing the voltage measuring device which can detect a surge voltage reliably.

  In order to achieve the above object, a voltage measuring apparatus according to claim 1 is a low-pass filter that removes a high-frequency component of an input signal, an A / D converter that samples a signal that has passed through the low-pass filter and outputs voltage calculation data, And a voltage measurement unit having a measurement circuit for measuring the voltage of the input signal based on the voltage calculation data, an A / D converter that samples the input signal and outputs surge voltage detection data, and the surge voltage detection A high-pass filter that generates surge voltage data corresponding to the surge voltage superimposed on the input signal from the data for comparison, and the voltage of the surge voltage indicated by the surge voltage data is compared with a reference value to compare the surge voltage A surge voltage detector having a detection circuit that outputs a detection signal when the voltage exceeds the reference value. To have.

  According to a second aspect of the present invention, there is provided the voltage measuring device according to the first aspect, wherein the first storage unit and a predetermined time before and after the output time when the detection signal is output from the detection circuit. And a control unit for storing the surge voltage data in the first storage unit.

  The voltage measuring device according to claim 3 is the voltage measuring device according to claim 1 or 2, wherein when the detection signal is output from the second storage unit and the detection circuit, a predetermined value is output before and after the output time point. A control unit that stores the voltage calculation data for a time in the second storage unit.

  According to the voltage measuring apparatus of claim 1, the voltage measuring unit having the low-pass filter, the A / D converter and the measuring circuit measures the voltage of the input signal, and the surge voltage having the A / D converter, the high-pass filter and the detecting circuit. The detection unit generates surge voltage data corresponding to the surge voltage, compares the surge voltage indicated by the surge voltage data with the reference value, and outputs a detection signal when the surge voltage exceeds the reference value Therefore, the surge voltage can be reliably detected because the above measurement error is not included in the surge voltage data that is directly generated in response to the surge voltage while accurately measuring the voltage of the input signal. it can. Further, the signal length of the surge voltage and the peak value of the surge voltage can be accurately measured based on the generated surge voltage data.

  According to the voltage measuring device of claim 2, the control unit stores the surge voltage data for a predetermined time before and after the output time when the detection signal is output from the detection circuit in the first storage unit, thereby causing the surge The change in the signal waveform of the surge voltage before and after the voltage detection time can be reliably recorded. Therefore, the measurer can accurately determine the cause of the surge voltage by displaying the recorded change in the signal waveform on the display unit or by processing the surge voltage data stored in the first storage unit. Can be analyzed.

  According to the voltage measuring device of claim 3, the control unit stores the voltage calculation data for a predetermined time before and after the output time when the detection signal is output from the detection circuit in the second storage unit, Since the input signal can be recorded over a relatively long time, the temporal positional relationship with respect to the input signal at the time when the surge voltage is generated can be reliably recorded. Therefore, the measurer displays the signal waveform of the recorded input signal and the position where the surge voltage is generated with respect to the signal waveform, for example, on the display unit, or performs signal processing on the voltage calculation data stored in the second storage unit. By doing so, the cause of the surge voltage can be accurately analyzed.

  The best mode of a voltage measuring apparatus according to the present invention will be described below with reference to the accompanying drawings.

  First, the configuration of the voltage measuring apparatus 1 to which the present invention is applied will be described. As shown in FIG. 1, the voltage measuring device 1 includes a voltage measuring unit 2, a surge voltage detection measuring unit 3, a control unit 4, a voltage calculation data storage unit 5, a surge voltage data storage unit 6, and a display unit 7. It is configured. The voltage measurement unit 2 includes a low-pass filter 21, an A / D converter 22, and a measurement circuit 23. The low-pass filter 21 is an anti-aliasing filter (anti-aliasing filter), and for example, receives an AC signal S0 (an example of an input signal in the present invention, see FIG. 2) supplied via a commercial power line. The low frequency component of 1/2 or less of the sampling clock used for the / D converter 22 is passed. The A / D converter 22 performs analog-to-digital conversion on the commercial signal AC signal S1 (see FIG. 3) that has passed through the low-pass filter 21 at a slightly slower (slower) sampling period, for example, 15360 Hz, and generates voltage calculation data Dw Generated and output to the measurement circuit 23 and the control unit 4. The measurement circuit 23 measures the voltage of the AC signal S0 (effective voltage, average voltage, peak voltage, etc., for example, effective voltage Ve) based on the voltage calculation data Dw under the control of the control unit 4.

  The surge voltage detection measurement unit 3 is a surge voltage detection unit according to the present invention, and includes an A / D converter 31, a high-pass filter 32, and a detection measurement circuit 33 as shown in FIG. The A / D converter 31 performs analog-to-digital conversion on the AC signal S0 supplied via the commercial power line, for example, at a fast sampling rate of 2 MHz (faster than the A / D converter 22), and detects a surge voltage. Data D0 (see FIG. 4) is generated and output to the high pass filter 32. The high-pass filter 32 is a digital high-pass filter that functions as a high-pass filter by digital signal processing, and is higher than the commercial power supply frequency (60 Hz in this example) from the surge voltage detection data D0 output by the A / D converter 31. Surge voltage data Dn (see FIG. 5) corresponding to the frequency component (noise or surge voltage) is output to the detection measurement circuit 33 and the control unit 4. The detection measurement circuit 33 is a detection circuit according to the present invention, and, based on the surge voltage data Dn, the absolute value of the surge voltage indicated by the surge voltage data Dn is a predetermined reference value Vr (same as the control circuit 4). When it exceeds (see the figure), a high level pulse signal Sp (see the figure) is output. Further, the detection measurement circuit 33 detects a period in which the absolute value of the surge voltage indicated by the surge voltage data Dn continuously exceeds the reference value Vr, for example, the signal length T2 ( Hereinafter, the surge voltage signal length T2) is measured. Further, the detection measurement circuit 33 detects the maximum value of the surge voltage continuously exceeding the reference value Vr, for example, the peak voltage Vp of the surge voltage shown in FIG. 5 (hereinafter also referred to as the surge voltage peak value Vp). taking measurement.

  The control unit 4 controls the voltage measurement unit 2 to measure, for example, the effective voltage Ve of the AC signal S0 as the measurement target. In addition, the control unit 4 temporarily stores the voltage calculation data Dw output from the voltage measurement unit 2 in the buffer 51 of the voltage calculation data storage unit 5. Further, the control unit 4 temporarily stores the surge voltage data Dn output from the surge voltage detection / measurement unit 3 in the buffer 61 of the surge voltage data storage unit 6. In addition, the control unit 4 controls the detection measurement circuit 33 of the surge voltage detection measurement unit 3 to detect the pulse signal Sp, and detects the superposition of the surge voltage on the AC signal S0 based on the detected pulse signal Sp. . Further, the control unit 4 controls the detection measurement circuit 33 to measure the surge voltage signal length T2 and the surge voltage peak value Vp, and stores the measured surge voltage signal length T2 and the surge voltage peak value Vp in the RAM 62. . Further, when the pulse signal Sp is output from the detection / measurement circuit 33, that is, when a surge voltage is detected, the control unit 4 detects the pulse signal Sp from the measurement start time (in this example, the measurement start time of the effective voltage Ve). Time (hereinafter also referred to as “surge voltage detection time T1”, see FIG. 5) is stored in the RAM 52 of the voltage calculation data storage unit 5 and also stored in the buffer 51. The voltage calculation data Dw for a predetermined time (for example, ± 10 mS centering on the output time) before and after the output time of the pulse signal Sp in the voltage calculation data Dw being stored is stored in the RAM 52. Furthermore, when the pulse signal Sp is output from the detection / measurement circuit 33, the control unit 4 includes a predetermined amount of time before and after the output time of the pulse signal Sp in the surge voltage data Dn stored in the buffer 61 (for example, The surge voltage data Dn of −100 μS to +200 μS from the output time point is stored in the RAM 62.

  The voltage calculation data storage unit 5 includes a buffer 51 and a RAM 52 corresponding to the second storage unit in the present invention. The buffer 51 temporarily stores voltage calculation data Dw transferred from the control unit 4. The RAM 52 stores the effective voltage Ve, the surge voltage detection time T1 and the surge voltage signal length T2 transferred from the control unit 4, and stores the voltage calculation data Dw stored in the buffer 51 according to the control of the control unit 4. To do. The surge voltage data storage unit 6 includes a buffer 61 and a RAM 62 corresponding to the first storage unit in the present invention. The buffer 61 temporarily stores the surge voltage data Dn transferred from the control unit 4. In this case, the buffer 61 stores the latest data of the input surge voltage data Dn while overwriting a predetermined recording area under the control of the control unit 4. The RAM 62 stores the surge voltage signal length T2 and the surge voltage peak value Vp transferred from the control unit 4 and stores the surge voltage data Dn stored in the buffer 61 according to the control of the control unit 4. The display unit 7 is configured by, for example, an LCD panel, and under the control of the control unit 4, the signal waveform of the input signal (in this example, the AC signal S1) based on the voltage calculation data Dw, the surge based on the surge voltage data Dn The voltage signal waveform, effective voltage Ve, surge voltage detection time T1, surge voltage signal length T2, surge voltage peak value Vp, and surge voltage generation position are displayed.

  Next, the overall operation of the voltage measuring apparatus 1 will be described.

  First, the low-pass filter 21 of the voltage measuring unit 2 inputs, for example, a 60 Hz AC signal S0 (see FIG. 2) supplied via a commercial power line, and the sampling clock used in the A / D converter 22 is input. An AC signal S1 (see FIG. 3) is output by removing frequency components exceeding 1/2. Next, the A / D converter 22 outputs the voltage calculation data Dw obtained by analog-digital conversion of the AC signal S1 in synchronization with a sampling clock of 15360 Hz, for example, to the measurement circuit 23 and the control unit 4. Subsequently, the measurement circuit 23 measures the effective voltage Ve of the AC signal S1 (that is, the AC signal S0) based on the voltage calculation data Dw under the control of the control unit 4, and outputs the effective voltage Ve to the control unit 4. In addition, the control unit 4 stores the voltage calculation data Dw in the buffer 51 of the voltage calculation data storage unit 5 and also stores the effective voltage Ve output from the measurement circuit 23 in the RAM 52 of the voltage calculation data storage unit 5. Let

  On the other hand, the A / D converter 31 of the surge voltage detection and measurement unit 3 inputs an AC signal S0 in parallel with the low-pass filter 21, and the AC signal S0 is analog-to-digital converted in synchronization with a sampling clock of 2 MHz, for example. The voltage detection data D0 is output to the high pass filter 32. Next, the high-pass filter 32 mainly removes the frequency component below the frequency of the AC signal S0 from the frequency component indicated by the surge voltage detection data D0 to generate surge voltage data Dn (see FIG. 5) corresponding only to the surge voltage. And output. Subsequently, the detection measurement circuit 33 compares the absolute value of the surge voltage indicated by the surge voltage data Dn with the reference value Vr. In this case, the detection measurement circuit 33 outputs a high-level pulse signal Sp to the control unit 4 when the absolute value of the surge voltage exceeds the reference value Vr. At this time, the control unit 4 detects the superposition of the surge voltage on the AC signal S0 based on the input of the pulse signal Sp, and detects the surge voltage from the measurement start time of the effective voltage Ve to the output time of the pulse signal Sp. The time T1 is stored in the RAM 52 of the voltage calculation data storage unit 5 and the voltage calculation data Dw stored in the buffer 51 of the voltage calculation data storage unit 5 before and after the output time point of the pulse signal Sp. The voltage calculation data Dw for a predetermined time is stored in the RAM 52. In addition, the control unit 4 determines, based on the input of the pulse signal Sp, for the predetermined time before and after the output time of the pulse signal Sp from the surge voltage data Dn stored in the buffer 61 of the surge voltage data storage unit 6. The surge voltage data Dn is stored in the RAM 62. Subsequently, the detection measurement circuit 33 measures a period in which the absolute value of the surge voltage continuously exceeds the reference value Vr as the surge voltage signal length T2 (see FIG. 5), outputs the surge voltage to the control unit 4, and The maximum value of the absolute value of the surge voltage during the period of the voltage signal length T2 is detected, and the surge voltage data Dn indicating the maximum value is output to the control unit 4 as the surge voltage peak value Vp. In response to this, the control unit 4 stores the surge voltage signal length T2 and the surge voltage peak value Vp in the RAM 62 of the surge voltage data storage unit 6.

  On the other hand, when the waveform display is instructed by the operation of the operation unit (not shown), the control unit 4 reads the voltage calculation data Dw, the surge voltage detection time T1 and the effective voltage Ve from the RAM 52, and the surge voltage data Dn, surge from the RAM 62. The voltage signal length T2 and the surge voltage peak value Vp are read and output to the display unit 7. In response to this, the display unit 7 displays the signal waveform of the AC signal S1 based on the voltage calculation data Dw, the effective voltage Ve, and the surge voltage generation position based on the surge voltage detection time T1 on the lower half of the LCD panel, for example. At the same time, the signal waveform of the surge voltage based on the surge voltage data Dn, the surge voltage signal length T2, and the surge voltage peak value Vp are displayed on the upper half of the LCD panel, for example. In this case, with respect to the position where the surge voltage is generated, for example, the position where the surge voltage is generated is directly indicated on the signal waveform of the AC signal S1 so that the position where the surge voltage is generated can be grasped with respect to the signal waveform of the AC signal S1. In addition, the time from a predetermined portion of the signal waveform can be displayed separately from the signal waveform. Accordingly, the measurer grasps the effective voltage Ve of the AC signal S0, the signal waveform of the AC signal S1 over a relatively long time before and after the occurrence of the surge voltage, and the positional relationship between the signal waveform and the surge voltage. It is possible to grasp the detailed signal waveform of the surge voltage having a relatively short time width, the surge voltage signal length T2, and the surge voltage peak value Vp. Therefore, the measurer can analyze the cause of the surge voltage by confirming the signal waveform of the AC signal S1 before and after the point of time when the surge voltage is generated, and confirming the detailed waveform of the surge voltage. It becomes.

  As described above, according to the voltage measuring apparatus 1, the voltage measuring unit 2 including the low-pass filter 21, the A / D converter 22, and the measuring circuit 23 measures the effective voltage Ve of the AC signal S 0 under the control of the control unit 4. The surge voltage detection / measurement unit 3 including the A / D converter 31, the high-pass filter 32, and the detection measurement circuit 33 generates the surge voltage data Dn corresponding to the surge voltage, and the surge voltage indicated by the surge voltage data Dn The voltage of the AC signal S0 (in this example, the effective voltage Ve) is accurately measured by comparing the voltage of the current and the reference value Vr and outputting the pulse signal Sp when the surge voltage exceeds the reference value Vr. However, since the measurement error described above is not included in the surge voltage data Dn directly generated in response to the surge voltage, the surge voltage can be detected reliably. That. Further, the surge voltage signal length T2 and the surge voltage peak value Vp can be accurately measured based on the generated surge voltage data Dn.

  Further, according to the voltage measuring apparatus 1, the control unit 4 stores the surge voltage data Dn for a predetermined time before and after the output time when the pulse signal Sp is output from the detection measurement circuit 33 in the RAM 62 of the surge voltage data storage unit 6. By doing so, changes in the signal waveform of the surge voltage before and after the detection point of the surge voltage can be reliably recorded. Therefore, the measurer displays the change in the recorded signal waveform on the display unit 7, for example, or processes the surge voltage data Dn stored in the RAM 62, thereby accurately analyzing the cause of the surge voltage. can do.

  Further, according to the voltage measuring apparatus 1, the voltage calculation data Dw for a predetermined time before and after the time when the control unit 4 outputs the pulse signal Sp from the detection measurement circuit 33 is output to the RAM 52 of the voltage calculation data storage unit 5. Since the AC signal S1 can be recorded over a relatively long period of time, the temporal positional relationship with respect to the AC signal S1 when the surge voltage is generated can be reliably recorded. Therefore, the measurer displays the signal waveform of the recorded AC signal S1 and the position where the surge voltage is generated with respect to the signal waveform, for example, on the display unit 7 or performs signal processing on the voltage calculation data Dw stored in the RAM 52. As a result, the cause of the surge voltage can be accurately analyzed.

1 is a block diagram showing a configuration of a voltage measuring device 1. FIG. It is a wave form diagram which shows the signal waveform of alternating current signal S0. 3 is a waveform diagram showing a signal waveform of an AC signal S1 that has passed through a low-pass filter 21. FIG. 3 is a waveform diagram showing a signal waveform of an AC signal S0 and a sampling position of surge voltage detection data D0 generated by an A / D converter 31. FIG. It is a wave form diagram which shows the signal waveform of the surge voltage, the sampling position of the surge voltage data Dn, and the pulse signal Sp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage measurement apparatus 2 Voltage measurement part 3 Surge voltage detection measurement part 4 Control part 5 Data storage part for voltage calculation 6 Data storage part for surge voltage detection 21 Low-pass filter 22, 31 A / D converter 23 Measurement circuit 32 High-pass filter 33 Detection Test circuit D0 Surge voltage detection data Dn Surge voltage data Dw Voltage calculation data S0, S1 AC signal Sp Pulse signal Ve Effective voltage Vr Reference value

Claims (3)

A low-pass filter that removes high-frequency components of the input signal, an A / D converter that samples the signal that has passed through the low-pass filter and outputs voltage calculation data, and measures the voltage of the input signal based on the voltage calculation data A voltage measurement unit having a measurement circuit to perform,
An A / D converter that samples the input signal and outputs surge voltage detection data; a high-pass filter that generates surge voltage data corresponding to the surge voltage superimposed on the input signal from the surge voltage detection data; and A surge voltage detector having a detection circuit that compares the voltage of the surge voltage indicated by the surge voltage data with a reference value and outputs a detection signal when the voltage of the surge voltage exceeds the reference value; Voltage measuring device. A first storage unit;
2. The voltage measurement according to claim 1, further comprising: a control unit that stores the surge voltage data for a predetermined time before and after the output time point when the detection signal is output from the detection circuit in the first storage unit. apparatus. A second storage unit;
3. A control unit that stores, in the second storage unit, the voltage calculation data for a predetermined time before and after the output time when the detection signal is output from the detection circuit. Voltage measuring device.

Images