JP2007121215A - Measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring device capable of setting accurately and surely a nominal voltage value used for monitoring a voltage or the like without a setting operation. <P>SOLUTION: The device includes a storage part 6 for storing a voltage data Dv indicating the plurality of nominal voltage values, a voltage detecting part 2 for detecting the voltage, and a computation control part 7 for determining any out of the plurality of nominal voltage values indicated by the voltage data Dv, based on the voltage detected the voltage detecting part 2, as the nominal voltage value of the voltage. The computation control part 7, for example, determines therein the nominal voltage value nearest to the detected voltage out of the plurality of nominal voltage values, as the nominal voltage value of the voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a measuring apparatus suitable for monitoring, for example, a line voltage or a phase voltage in a plurality of electric wires to which an AC voltage is applied.

As this type of measuring apparatus, a voltage monitoring apparatus disclosed in Japanese Patent Laid-Open No. 2000-74957 is known. This voltage monitoring apparatus includes a reference value setting unit configured to be able to set a nominal voltage value of a voltage to be monitored (“reference value” in the publication), and a monitoring condition configured to be able to set a monitoring condition of the voltage to be monitored A setting unit; and a notification unit that determines whether or not the monitored voltage satisfies a predetermined condition and notifies the result. In this case, the monitoring condition setting unit includes an upper limit monitoring voltage setting unit configured to be able to set the upper limit range of the monitored voltage and a lower limit monitoring voltage setting unit configured to be able to set the lower limit range of the monitored voltage. Has been. In this upper limit monitoring voltage setting section, the upper limit range for the monitoring voltage (voltage to be monitored) is set as a ratio (% numerical value) to the nominal voltage value, and in the lower limit monitoring voltage setting section, the lower limit range for the monitoring voltage is the ratio to the nominal voltage value. Set as At this time, in an abnormal state where the monitoring voltage exceeds the set upper limit range or falls below the lower limit range, the upper limit voltage monitoring operation display unit or the lower limit voltage monitoring operation display unit as a notification means lights up and the monitoring voltage is Announce abnormality.
JP 2000-74957 A (page 3, FIG. 1)

  However, the conventional voltage monitoring apparatus has the following problems. That is, in this voltage monitoring apparatus, the user must set a nominal voltage value for monitoring the voltage by himself / herself. For this reason, for example, when a nominal voltage value different from the nominal voltage value actually supplied to the electric wire is set incorrectly, the condition for monitoring the voltage is also set to an incorrect value. Therefore, this voltage monitoring device has a problem that there is a possibility that the voltage cannot be accurately monitored.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a measuring apparatus that can accurately and reliably set a nominal voltage value used for voltage monitoring or the like without performing a setting operation.

  In order to achieve the above object, the measuring apparatus according to claim 1 is configured such that the storage unit stores a plurality of nominal voltage values, the voltage detection unit detects a voltage, and the plurality of voltages based on the voltage detected by the voltage detection unit. And a control unit that determines any one of the nominal voltage values as the nominal voltage value of the voltage.

  The measuring device according to claim 2 is the measuring device according to claim 1, wherein the control unit calculates a nominal voltage value closest to the detected voltage from the plurality of nominal voltage values. Determined as voltage value.

  Further, in the measurement apparatus according to claim 3, in the measurement apparatus according to claim 1, the storage unit stores a voltage range associated with each of the plurality of nominal voltage values, and the control unit It is determined to which of the plurality of voltage ranges the detected voltage belongs, and the nominal voltage value associated with the determined voltage range is determined as the nominal voltage value of the voltage.

  According to a fourth aspect of the present invention, there is provided the measuring apparatus according to any one of the first to third aspects, further comprising a current detection unit that detects a current flowing in any of the plurality of electric wires, and the voltage detection unit. Detects the voltage between the line voltage and the phase voltage of the AC voltage in the plurality of electric wires, and the storage unit stores the plurality of nominal voltage values for each of the plurality of electric methods in the AC method. The control unit is at least one of the number of the electric wires to which the AC voltage obtained based on the voltage detected by the voltage detection unit is applied and a phase difference between the detected voltage and the current And determining one of the plurality of nominal voltage values for the determined electric method as the nominal voltage value of the voltage.

  The measuring device according to claim 5 is the measuring device according to any one of claims 1 to 4, wherein the control unit monitors a voltage value of the detected voltage, and the voltage value is the nominal voltage. It is determined that an abnormality has occurred when the voltage deviates from the value by a predetermined voltage or more.

  According to the measuring apparatus of claim 1, the control unit sets one of a plurality of nominal voltage values stored in the storage unit based on the voltage detected by the voltage detection unit as the nominal voltage value of the voltage. By determining, the nominal voltage value that best matches the voltage to be detected can be automatically determined. Therefore, compared with a conventional voltage monitoring device that manually sets the nominal voltage value, the nominal voltage value used for voltage monitoring or the like can be set accurately and reliably without performing a setting operation.

  According to the measuring apparatus of claim 2, the control unit determines the nominal voltage value closest to the detected voltage from the plurality of nominal voltage values as the nominal voltage value of the voltage, thereby simplifying processing. However, the nominal voltage value that most closely matches the voltage to be detected can be reliably set.

  According to the measuring apparatus of claim 3, the control unit determines to which of the voltage ranges associated with each of the plurality of nominal voltage values the detected voltage belongs and corresponds to the determined voltage range. By determining the assigned nominal voltage value as the nominal voltage value of the voltage, for example, by setting the upper limit value and the lower limit value of each voltage range based on the values that can be actually detected by the voltage to be detected, A suitable nominal voltage value can be set accurately. In addition, when trying to set the nominal voltage value in a state where the voltage is not within each voltage range for some reason, the control unit can determine that the voltage is an incorrect value and an abnormal state has occurred. . Therefore, for example, an error can be displayed without determining the nominal voltage value, or the user can be prompted to set the nominal voltage value. The situation where it is set can be avoided.

  According to the measurement device of claim 4, the control unit determines the electrical method based on at least one of the number of electric wires to which an AC voltage is applied and the detected voltage and current phase difference. At the same time, it is possible to automatically determine the electrical method by determining any one of a plurality of nominal voltage values for the determined electrical method as the nominal voltage value of the AC voltage, so that the setting operation is not performed. The electrical system and the nominal voltage value can be set reliably.

  According to the measuring apparatus of claim 5, the control unit determines that an abnormality has occurred when the voltage value of the detected voltage is more than a predetermined voltage from the nominal voltage value, thereby detecting the voltage to be detected. Since the occurrence of abnormality can be determined based on the nominal voltage value that best matches the above, the occurrence of abnormality can be accurately determined. In addition, the occurrence of abnormality can be accurately notified.

  Hereinafter, the best mode of a measuring apparatus according to the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the measuring apparatus 1 will be described with reference to the drawings.

  The measuring device 1 is a voltage monitoring device that monitors power supply quality (for example, a voltage waveform) in a power supply line connecting between a power supply and a load. As shown in FIG. The D conversion units 3 a, 3 b, 3 c, 5, the current detection unit 4, the storage unit 6, the calculation control unit 7, the operation unit 8, the display unit 9, and the output unit 10 are configured. In this case, the measuring apparatus 1 is used, for example, to monitor the voltage waveform of the line voltage Vab in the two electric wires La and Lb (see FIG. 2) to which an AC voltage is applied in a one-phase two-wire system. . Moreover, the measuring apparatus 1 is a voltage waveform of the line voltages Vrs, Vrt, Vst in the electric wires Lr, Ls, Lt (see FIG. 3) to which an alternating voltage is applied in a three-phase three-wire system, or a three-phase four-wire. The voltage waveforms of the phase voltages Vr, Vs, and Vt in the electric wires Lr, Ls, Lt, and Ln to which an alternating voltage is applied in the equation (see FIG. 4, hereinafter, also referred to as the electric wire L when not distinguished from each other) are monitored. Also used for.

  As shown in FIGS. 1 to 4, the voltage detection unit 2 includes six voltage probes 2a to 2f and three amplifiers 2g, 2h, and 2i, and includes electric wires La and Lb (see FIG. 2) and electric wires Lr to Lt. (See FIG. 3) and line voltages Vab, Vrs, Vrt, Vst and phase voltages Vr, Vs, Vt (voltages Vab, Vrs, Vrt, Vst, Vr, Vt) as detection targets in the electric wires Lr to Ln (see FIG. 4). When Vs and Vt are not distinguished from each other, all of the voltage V) can be detected. The voltage probes 2a and 2b have their output terminals connected to the input terminal of the amplifier 2g, the voltage probes 2c and 2d have their output terminals connected to the input terminal of the amplifier 2h, and the voltage probes 2e and 2f have their respective output terminals Is connected to the input end of the amplifier 2i. In this case, for example, as shown in FIG. 2, when monitoring the voltage waveform of the line voltage Vab, the voltage probe 2a is connected to the electric wire La, and the voltage probe 2b is connected to the electric wire Lb. The remaining voltage probes 2c to 2f are not connected to any wires. At this time, the amplifier 2g amplifies the potential of the voltage probe 2a with respect to the potential of the voltage probe 2b (hereinafter also referred to as a voltage between the voltage probes 2a and 2b) with a predetermined gain to indicate the voltage value of the line voltage Vab. The detection signal S1 is output to the A / D converter 3a. Further, the A / D conversion unit 3a performs analog-digital (A / D) conversion on the detection signal S1, generates a digital signal S2 indicating the voltage value of the line voltage Vab, and outputs the digital signal S2 to the arithmetic control unit 7.

  Further, as shown in FIG. 3, when monitoring the voltage waveforms of the line voltages Vrs, Vrt, Vst, the two voltage probes 2a, 2c are connected to the R-phase electric wire Lr, and the two voltage probes 2b, 2e are connected. Connect to the S-phase wire Ls, and connect the voltage probes 2d and 2f to the T-phase wire Lt. At this time, the amplifier 2g amplifies the voltage between the voltage probes 2a and 2b with a predetermined gain and outputs a detection signal S1 indicating the voltage value of the line voltage Vrs to the A / D converter 3a. The amplifier 2h The detection signal S3 indicating the voltage value of the line voltage Vrt by amplifying the potential of the voltage probe 2c with respect to the potential of the voltage probe 2d (hereinafter also referred to as voltage between the voltage probes 2c and 2d) with a predetermined gain is A / D. The amplifier 2i outputs to the conversion unit 3b, and the amplifier 2i amplifies the potential of the voltage probe 2f with respect to the potential of the voltage probe 2e (hereinafter also referred to as the voltage between the voltage probes 2e and 2f) with a predetermined gain to generate the voltage of the line voltage Vst A detection signal S5 indicating the value is output to the A / D converter 3b. In this case, the A / D conversion unit 3a outputs a digital signal S2 obtained by A / D converting the detection signal S1 to the arithmetic control unit 7, and the A / D conversion unit 3b converts the detection signal S3 by A / D conversion. The signal S4 is output to the calculation control unit 7, and the A / D conversion unit 3c outputs a digital signal S6 obtained by A / D converting the detection signal S5 to the calculation control unit 7.

  As shown in FIG. 4, when monitoring the voltage waveforms of the phase voltages Vr, Vs, Vt, the voltage probe 2a is connected to the R-phase electric wire Lr, the voltage probe 2c is connected to the S-phase electric wire Ls, The voltage probe 2e is connected to the T-phase wire Lt, and the three voltage probes 2b, 2d, and 2f are connected to the neutral-phase wire Ln. At this time, the amplifier 2g amplifies the voltage between the voltage probes 2a and 2b with a predetermined gain and outputs a detection signal S1 indicating the voltage value of the phase voltage Vr to the A / D converter 3a. The amplifier 2h The voltage between the voltage probes 2c and 2d is amplified with a predetermined gain and a detection signal S3 indicating the voltage value of the phase voltage Vs is output to the A / D converter 3b. The amplifier 2i is a voltage between the voltage probes 2e and 2f. And a detection signal S5 indicating the voltage value of the phase voltage Vt is output to the A / D converter 3b. In this case, the A / D conversion unit 3a outputs a digital signal S2 obtained by A / D converting the detection signal S1 to the arithmetic control unit 7, and the A / D conversion unit 3b converts the detection signal S3 by A / D conversion. The signal S4 is output to the calculation control unit 7, and the A / D conversion unit 3c outputs a digital signal S6 obtained by A / D converting the detection signal S5 to the calculation control unit 7.

  On the other hand, as shown in FIG. 1, the current detection unit 4 includes a clamp-type current probe 4a and an amplifier 4b. When the current probe 4a monitors the line voltages Vrs, Vrt, Vst (see FIG. 3) or the phase voltages Vr, Vs, Vt (see FIG. 4), the current probe 4a is connected to any of the electric wires Lr to Lt (for example, the electric wire Lr). Connected. In this case, the current probe 4a detects the current Ir flowing through the electric wire Lr and outputs a detection signal indicating the current value to the amplifier 4b. The amplifier 4b amplifies the detection signal output from the current probe 4a with a predetermined gain, and outputs a detection signal S7 indicating the current value of the current Ir to the A / D conversion unit 5. The A / D converter 5 outputs a digital signal S8 obtained by A / D converting the detection signal S7 to the calculation controller 7.

  The storage unit 6 stores voltage data Dv indicating a plurality of nominal voltage values Vn as a criterion for determining whether the power quality is good or bad. Specifically, as shown in FIG. 5, the storage unit 6 includes three one-phase two-wire type, three-phase three-wire type, and three-phase four-wire type as voltage data Dv (a plurality of examples in the present invention). A plurality of nominal voltage values Vn for each of the electrical methods in the AC method are stored. In this case, for the one-phase two-wire system, the storage unit 6 has eight nominal voltage values Vn (100V, 110V, 120V, 200V, 220V, 230V, 240V and 277V). In addition, for the three-phase three-wire system, the storage unit 6 has nine nominal voltage values Vn (110V, 200V, 220V, 347V, 380V, 400V, 415V) indicated by a circle in the three-phase three-wire system column of FIG. 480V and 600V). Further, for the three-phase four-wire system, the storage unit 6 has seven nominal voltage values Vn (120V, 200V, 220V, 230V, 240V, 277V and 347V) indicated by a circle in the three-phase four-wire system column of FIG. ) Is memorized. The storage unit 6 also stores digital signals S2, S4, S6, S8, abnormal data Du, and determined voltage data Dvd, as will be described later.

  The arithmetic control unit 7 corresponds to the control unit in the present invention, and obtains the number of electric wires L to which an AC voltage is applied based on the voltage V in the monitored electric wire L, and based on the obtained number of electric wires L. It is determined whether the electrical system in the AC system is “1-phase 2-wire system” and “3-phase 3-wire system or 3-phase 4-wire system”. Further, when the arithmetic control unit 7 determines that the electrical system is “three-phase three-wire system or three-phase four-wire system”, the arithmetic control unit 7 calculates the voltage V (exactly, for example, the line voltage Vrs or the phase voltage Vr). Based on the phase difference between the voltage waveform and the current waveform of the current Ir, it is determined whether the electrical method is “three-phase three-wire” or “three-phase four-wire”. In addition, the arithmetic control unit 7 converts any one of a plurality of nominal voltage values Vn indicated by the voltage data Dv into the nominal voltage value Vn of the AC voltage based on the voltage V in the monitored electric wire L and the determined electrical method. And the determined voltage data Dvd indicating the determined nominal voltage value Vn is stored in the storage unit 6. Furthermore, the arithmetic control unit 7 monitors the voltage waveform with reference to the nominal voltage value Vn indicated by the determined voltage data Dvd, and determines that an abnormality has occurred when the voltage V is more than a predetermined voltage away from the nominal voltage value Vn. Thus, the storage unit 6 stores the abnormality data Du indicating the type of abnormality, the date and time of occurrence, and the voltage waveform before and after that. The voltage detector 2, the A / D converters 3 a to 3 c, the storage unit 6, and the calculation controller 7 measure voltage values of line voltages and phase voltages in the plurality of electric wires L and generate voltage waveforms. The part is composed. In addition, a current measuring unit that measures the current value of the current flowing through one of the electric wires L by the current detection unit 4, the A / D conversion unit 5, the storage unit 6, and the calculation control unit 7 and generates a current waveform is configured. Is done.

  The operation unit 8 outputs an instruction signal corresponding to the operation content operated by the user to the calculation control unit 7. The display unit 9 displays the voltage waveform of the voltage V in the plurality of electric wires L to be monitored. The display unit 9 displays information such as the type of abnormality, the date and time of occurrence, the voltage waveform, and the like indicated by the abnormality data Du according to the control by the arithmetic control unit 7. The output unit 10 has a communication function for data communication with a storage device, a display device, and the like provided outside, and outputs abnormal data Du to the external device according to control by the arithmetic control unit 7.

  Next, the overall operation of the measuring apparatus 1 will be described with reference to the drawings.

  First, processing when monitoring the voltage waveform of the line voltage Vab will be described. In this case, as shown in FIG. 2, the voltage probes 2a and 2b are connected to the electric wires La and Lb, respectively. At this time, the amplifier 2g outputs a detection signal S1 indicating the voltage value of the line voltage Vab to the A / D conversion unit 3a, and the A / D conversion unit 3a converts the detection signal S1 into a digital signal. S2 is output to the arithmetic control unit 7.

  Next, the arithmetic control unit 7 stores the voltage value of the line voltage Vab indicated by the digital signal S2 in the storage unit 6 for a predetermined period of the AC voltage applied to the electric wire L. Subsequently, the arithmetic control unit 7 reads out the voltage value for one cycle of the line voltage Vab stored in the storage unit 6, and based on the read voltage value for one cycle, the effective value (the actual value of the line voltage Vab) (Corresponding to the voltage in the invention). Moreover, the arithmetic control part 7 calculates | requires the number of the electric wires L to which the alternating voltage is applied based on digital signal S2. In this case, since one digital signal S2 is input, the arithmetic control unit 7 determines that the number of the electric wires L to which the AC voltage is applied is two (one set). At this time, the arithmetic control unit 7 determines that the AC voltage applied to the monitored electric wire L based on the obtained number of electric wires L is “one-phase two-wire type” and “three-phase three-wire type or three-phase type”. It is determined whether it is “4-wire type”. Specifically, when the number of the electric wires L is two (one set) or less, the arithmetic control unit 7 determines that the one-phase two-wire system is used, and the number of the electric wires L is two (1 When it exceeds the set), it is determined that it is either “3-phase 3-wire system” or “3-phase 4-wire system”. In this case, since the number of the electric wires L is two, the arithmetic control unit 7 determines that the electric method is “one-phase two-wire type”.

  Subsequently, based on the calculated effective value of the line voltage Vab and the determined electrical method, the arithmetic control unit 7 converts any of the plurality of nominal voltage values Vn indicated by the voltage data Dv to the nominal voltage of the AC voltage. It is determined as the value Vn and is stored in the storage unit 6 as determined voltage data Dvd. Specifically, the arithmetic control unit 7 determines the nominal voltage value Vn closest to the effective value of the line voltage Vab as the nominal voltage value Vn of the AC voltage among the plurality of nominal voltage values Vn indicated by the voltage data Dv. To do. For example, when the effective value of the line voltage Vab is “104 V”, the arithmetic control unit 7 selects “100 V” closest to “104 V” from among the eight nominal voltage values Vn for the one-phase two-wire system shown in FIG. Is determined as the nominal voltage value Vn of the AC voltage.

  Next, the arithmetic control unit 7 monitors the voltage waveform of the line voltage Vab based on the nominal voltage value Vn indicated by the determined voltage data Dvd. In this case, the arithmetic control unit 7 calculates the effective value of the line voltage Vab for each cycle of the voltage value indicated by the digital signal S2, and the calculated effective value of the line voltage Vab is determined from the nominal voltage value Vn by a predetermined voltage ( For example, it is determined that an abnormality has occurred when the distance is greater than or equal to 10% of the nominal voltage value Vn. For example, the arithmetic control unit 7 determines that a dip has occurred when the effective value of the line voltage Vab is lower than the nominal voltage value Vn by a predetermined voltage (that is, 90 V or less), and the effective value of the line voltage Vab is determined. When the value exceeds the nominal voltage value Vn by a predetermined voltage (that is, 110 V or more), it is determined that a swell has occurred. In this case, since the occurrence of abnormality is determined based on the nominal voltage value Vn that most closely matches the voltage V actually applied to the wire L, the occurrence of abnormality is accurately determined. On the other hand, when an abnormality occurs, the arithmetic control unit 7 executes a storage process in which the abnormality data Du indicating the type of abnormality, the date and time of occurrence of the abnormality, and the voltage waveform before and after the abnormality is stored in the storage unit 6. When an instruction signal for displaying the information indicated by the abnormal data Du is output from the operation unit 8, the arithmetic control unit 7 executes a display process for displaying the information indicated by the abnormal data Du on the display unit 9. Further, when an instruction signal for outputting the abnormal data Du to the external device is output from the operation unit 8, the arithmetic control unit 7 outputs the abnormal data Du to the external device via the output unit 10, thereby An output process for displaying information indicated by the data Du on an external display device to notify the user or storing the abnormal data Du in an external storage device is executed.

  Next, processing when monitoring the voltage waveforms of the line voltages Vrt, Vrt, Vst will be described. In this case, as shown in FIG. 3, the voltage probes 2a to 2f are connected to the electric wires Lr to Lt, respectively, and the current probe 4a is connected to the electric wire Lr. At this time, each of the amplifiers 2g to 2i amplifies each voltage input via each of the voltage probes 2a to 2f to detect the detection signals S1, S3, and S5 indicating the voltage values of the three line voltages Vrt, Vrt, and Vst. Are output to the A / D converters 3a to 3c, and the A / D converters 3a to 3c control the digital signals S2, S4, and S6 obtained by A / D converting the detection signals S1, S3, and S5. Output to unit 7. On the other hand, the amplifier 4b outputs a detection signal S7 indicating the current value of the current Ir input via the current probe 4a to each A / D converter 5, and the A / D converter 5 outputs the detection signal S7 to the A / D. The D-converted digital signal S8 is output to the arithmetic control unit 7.

  Next, the arithmetic control unit 7 stores the voltage values of the line voltages Vrs, Vrt, Vst indicated by the digital signals S2, S4, S6 and the current value of the current Ir indicated by the digital signal S8 for a predetermined period. Remember me. Subsequently, the arithmetic control unit 7 reads out the voltage values for one cycle of the line voltages Vrs, Vrt, Vst stored in the storage unit 6 respectively, and based on the read voltage values for one cycle, the line voltage Vrs. , Vrt, and Vst are calculated as effective values. Moreover, the arithmetic control part 7 calculates | requires the number of the electric wires L to which the alternating voltage is applied based on digital signal S2, S4, S6. In this case, since the three digital signals S2, S4, S6 are input, the arithmetic control unit 7 determines that the number of the electric wires L to which the AC voltage is applied is three (three sets). At this time, since the number of the electric wires L obtained by the arithmetic control unit 7 exceeds two (one set), the electric method is either “three-phase three-wire” or “three-phase four-wire”. It is determined that Next, the arithmetic control unit 7 reads out one cycle of the digital signals S2 and S8 stored in the storage unit 6, and is specified by the voltage waveform of the line voltage Vrs specified by the digital signal S2 and the digital signal S8. When the phase difference between the current Ir and the current waveform is 30 degrees, it is determined that the electrical form is “three-phase three-wire system”, and when the phase difference is 0 degrees (both waveforms are in phase). The electrical form is determined to be “3-phase 4-wire type”. In this case, since the phase difference is 30 degrees, the arithmetic control unit 7 determines that the electrical format is “three-phase three-wire”.

  Subsequently, the arithmetic control unit 7 determines the nominal voltage value Vn of the AC voltage based on the calculated effective values of the line voltages Vrs, Vrt, Vst and the determined electrical method, and also stores the determined voltage data Dvd as the determined voltage data Dvd. Remember me. For example, when the average value of the effective values of the line voltages Vrs, Vrt, Vst is “104 V”, the arithmetic control unit 7 selects “9 nominal voltage values Vn for the three-phase three-wire system shown in FIG. “110 V” closest to “104 V” is determined as the nominal voltage value Vn of the AC voltage. Subsequently, the arithmetic control unit 7 performs the above storage process while monitoring the voltage waveforms of the line voltages Vrs, Vrt, Vst with reference to the nominal voltage value Vn indicated by the determined voltage data Dvd. In addition, when an instruction signal is output from the operation unit 8, the arithmetic control unit 7 performs display processing and output processing corresponding to the instruction signal.

  Next, processing when monitoring the voltage waveforms of the phase voltages Vr, Vs, Vt will be described. In this case, as shown in FIG. 4, the voltage probes 2a to 2f are connected to the electric wires Lr to Ln, respectively, and the current probe 4a is connected to the electric wire Lr. At this time, the amplifiers 2g to 2i amplify the voltages input through the voltage probes 2a to 2f to generate detection signals S1, S3, and S5 indicating the voltage values of the three phase voltages Vr, Vs, and Vt. The A / D converters 3a to 3c output the signals, and the A / D converters 3a to 3c calculate the digital signals S2, S4, and S6 obtained by A / D converting the detection signals S1, S3, and S5. 7 is output. On the other hand, the amplifier 4b outputs a detection signal S7 indicating the current value of the current Ir input via the current probe 4a to each A / D converter 5, and the A / D converter 5 outputs the detection signal S7 to the A / D. The D-converted digital signal S8 is output to the arithmetic control unit 7.

  Next, the arithmetic control unit 7 stores the voltage values of the phase voltages Vr, Vs, Vt indicated by the digital signals S2, S4, S6 and the current value of the current Ir indicated by the digital signal S8 in the storage unit 6 for a predetermined period. Remember me. Subsequently, the arithmetic control unit 7 reads out the voltage values for one cycle of the phase voltages Vr, Vs, and Vt stored in the storage unit 6, respectively, and based on the read voltage values for one cycle, the phase voltages Vr, Vs. , Vt effective values are calculated. Moreover, the arithmetic control part 7 calculates | requires the number of the electric wires L to which the alternating voltage is applied based on digital signal S2, S4, S6. In this case, since the three digital signals S2, S4, S6 are input, the arithmetic control unit 7 determines that the number of the electric wires L to which the AC voltage is applied is three (three sets). At this time, since the number of the electric wires L obtained by the arithmetic control unit 7 exceeds two (one set), the electric method is either “three-phase three-wire” or “three-phase four-wire”. It is determined that Subsequently, the arithmetic control unit 7 reads out one cycle of the digital signals S2 and S8 stored in the storage unit 6, and the electrical method is either “three-phase three-wire” or “three-phase four-wire”. Is determined. In this case, since the phase difference between the voltage waveform of the phase voltage Vr specified by the digital signal S2 and the current waveform of the current Ir specified by the digital signal S8 is 0 degree, the arithmetic control unit 7 has its electrical format. Is “3-phase 4-wire type”.

  Subsequently, the arithmetic control unit 7 determines the nominal voltage value Vn of the AC voltage based on the calculated effective values of the phase voltages Vr, Vs, Vt and the determined electrical method, and stores the determined voltage data Dvd in the storage unit 6. Remember me. For example, when the average value of the effective values of the phase voltages Vr, Vs, and Vt is “104 V”, the arithmetic control unit 7 selects “104 V” from the seven nominal voltage values Vn for the three-phase four-wire system shown in FIG. "120 V" closest to "" is determined as the nominal voltage value Vn of the AC voltage. Subsequently, the arithmetic control unit 7 performs the above storage process while monitoring the voltage waveforms of the phase voltages Vr, Vs, Vt with reference to the nominal voltage value Vn indicated by the determined voltage data Dvd. In addition, when an instruction signal is output from the operation unit 8, the arithmetic control unit 7 performs display processing and output processing corresponding to the instruction signal.

  Thus, according to this measuring apparatus 1, the arithmetic control unit 7 sets any one of the plurality of nominal voltage values Vn indicated by the voltage data Dv as the nominal voltage value Vn of the AC voltage based on the effective value of the voltage V. By determining, the nominal voltage value Vn that most closely matches the voltage V actually applied to the electric wire L can be automatically determined. Therefore, according to this measuring device 1, compared with the conventional voltage monitoring device that manually sets the nominal voltage value Vn, the nominal voltage value Vn used for voltage monitoring or the like can be set accurately and reliably without performing a setting operation. can do.

  Further, according to the measuring apparatus 1, the arithmetic control unit 7 sets the nominal voltage value Vn closest to the effective value of the voltage V among the plurality of nominal voltage values Vn indicated by the voltage data Dv as the nominal voltage value Vn of the AC voltage. By determining, it is possible to reliably set the nominal voltage value Vn that most closely matches the voltage V actually applied to the electric wire L, though it is a simple process.

  Furthermore, according to this measuring apparatus 1, the calculation control unit 7 determines the number of the electric wires L to which the AC voltage is applied and the detected voltage V (to be exact, either the line voltage Vrs or the phase voltage Vr). ) And the phase difference of the current Ir, and by determining one of a plurality of nominal voltage values Vn for the determined electrical method as the nominal voltage value Vn of the AC voltage, Since the method can be automatically discriminated, the electric method and the nominal voltage value Vn can be reliably set without performing the setting operation. Moreover, according to this measuring apparatus 1, the calculation control part 7 discriminate | determines that abnormality has generate | occur | produced when the voltage V left | separated more than the predetermined voltage from the nominal voltage value Vn which the determination voltage data Dvd shows, Therefore As a result of being able to determine the occurrence of an abnormality based on the nominal voltage value Vn that most closely matches the actually applied voltage V, it is also possible to accurately notify the occurrence of the abnormality.

  In addition, this invention is not limited to said structure. For example, the calculation control unit 7 has been described above with respect to an example in which the nominal voltage value Vn closest to the effective value of the voltage V is determined as the nominal voltage value Vn of the AC voltage from among the plurality of nominal voltage values Vn indicated by the voltage data Dv. It is not limited to this. For example, as shown in FIG. 6, the storage unit 6 stores voltage range data Dva indicating a voltage range (voltage value range) associated with each of the plurality of nominal voltage values Vn, and the arithmetic control unit 7 A configuration is adopted in which the effective value of the voltage V belongs to which of the plurality of voltage ranges and the nominal voltage value Vn associated with the determined voltage range is determined as the nominal voltage value Vn of the AC voltage. You can also. In this case, the upper limit value and the lower limit value of each voltage range in the voltage range data Dva are set so that the effective value of the voltage V can be actually taken. For example, as shown in FIG. 6, in the one-phase two-wire system, the voltage range in which the nominal voltage value Vn is associated with “100V” is set to “80V to 107V”, and the nominal voltage value Vn is set to “110V”. The associated voltage range is set to “108V to 115V”.

  In this case, for example, when the effective value of the line voltage Vab in the electric wires La and Lb shown in FIG. 2 is “106 V”, the arithmetic control unit 7 has eight voltage ranges for the one-phase two-wire type shown in FIG. It is determined to which “106 V” belongs, and “100 V” associated with the voltage range “80 V to 107 V” determined to belong to “106 V” is determined as the nominal voltage value Vn of the AC voltage. In this case, since the upper limit value and the lower limit value of each voltage range are set to values that the effective value of the line voltage Vab can actually take, the nominal voltage value Vn that matches the actual situation can be set accurately. In addition, the nominal voltage value Vn is set in a state where the effective value of the voltage V is not within each voltage range indicated by the voltage range data Dva (for example, “0V”) due to a disconnection or the like occurring in the electric wire L. When this occurs, the arithmetic control unit 7 can determine that the voltage V is an incorrect value and an abnormal state has occurred. Therefore, in this case, for example, an error display may be displayed on the display unit 9 without determining the nominal voltage value Vn, or the user may be prompted to set the nominal voltage value Vn using the operation unit 8. As a result, even if an abnormal state such as disconnection occurs in the electric wire L, it is possible to avoid a situation in which an incorrect nominal voltage value Vn is set. Further, when the nominal voltage value Vn determined in the past is stored in the storage unit 6 as the determined voltage data Dvd, when the arithmetic control unit 7 determines that the voltage V is an incorrect value, the determined voltage data A configuration in which the nominal voltage value Vn indicated by Dvd is determined as the nominal voltage value Vn of the AC voltage can also be adopted. In this case, for example, since the same user often monitors the electric wire L to which the AC voltage having the same nominal voltage value Vn is applied, the nominal voltage value Vn that matches the use state can be determined. .

  In addition, the electric system is determined by only one of the number of electric wires L to which an AC voltage is applied, the voltage V (exactly one of the line voltage Vrs and the phase voltage Vr, for example), and the phase difference of the current Ir. A configuration for discriminating can also be adopted. For example, the arithmetic control unit 7 determines the electrical system only by the number of the electric wires L to which the AC voltage is applied, and the electrical system is “1-phase 2-wire system” and “3-phase 3-wire system or 3-phase 4”. It is possible to adopt a configuration in which only one of “linear type” is discriminated. In this case, the arithmetic control unit 7 causes the user to set the electrical method to either “3-phase 3-wire system” or “3-phase 4-wire system” using the operation unit 8. According to this configuration, since the current probe 4a is not required, the measuring apparatus 1 can be configured simply and inexpensively. Furthermore, it is also possible to adopt a configuration in which the arithmetic control unit 7 allows the user to select an electric method from the above three electric methods without determining the electric method. Moreover, although the example which monitors an alternating voltage was demonstrated, this invention is not restricted to this, For example, the nominal voltage value arbitrarily set with respect to direct current voltage is set, and it is based on the nominal voltage value. Of course, the present invention can also be applied to a voltage monitoring device that performs voltage monitoring.

1 is a configuration diagram of a measuring device 1. FIG. It is a block diagram which shows the measurement system comprised by two electric wires La and Lb. It is a block diagram which shows a measurement system comprised with three electric wires Lr-Lt. It is a block diagram which shows the measurement system comprised by four electric wires Lr-Ln. It is a data structure figure which shows the voltage data Dv. It is a data structure figure which shows the voltage range data Dva.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 2 Voltage detection part 4 Current detection part 6 Memory | storage part 7 Operation control part 8 Operation part 9 Display part Dv Voltage data Dva Voltage range data La, Lb, Lr, Ls, Lt, Ln Electric wire Vab, Vrs, Vrt, Vst Line voltage Vr, Vs, Vt Phase voltage

Claims (5)

  A storage unit for storing a plurality of nominal voltage values, a voltage detection unit for detecting a voltage, and a nominal voltage of the voltage based on the voltage detected by the voltage detection unit. And a control unit that determines the value.   The measurement apparatus according to claim 1, wherein the control unit determines a nominal voltage value closest to the detected voltage among the plurality of nominal voltage values as a nominal voltage value of the voltage. The storage unit stores a voltage range associated with each of the plurality of nominal voltage values,
The control unit determines to which of the plurality of voltage ranges the detected voltage belongs and determines the nominal voltage value associated with the determined voltage range as a nominal voltage value of the voltage. Item 1. The measuring apparatus according to Item 1. Provided with a current detection unit that detects current flowing in any of the plurality of electric wires,
The voltage detection unit detects a voltage between a line voltage and a phase voltage of an AC voltage in the plurality of electric wires,
The storage unit stores the plurality of nominal voltage values for each of a plurality of electrical systems in an AC system,
The control unit includes at least one of the number of the electric wires to which the AC voltage obtained based on the voltage detected by the voltage detection unit is applied and the detected phase difference between the voltage and the current. The measurement according to any one of claims 1 to 3, wherein the electrical system is determined based on the determination, and any one of the plurality of nominal voltage values for the determined electrical system is determined as a nominal voltage value of the voltage. apparatus.   The said control part monitors the voltage value of the said detected voltage, and discriminate | determines that abnormality generate | occur | produced when the said voltage value leaves | separated from the said nominal voltage value more than predetermined voltage. Measuring device.

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