JP6512604B2 - Voltage detection sensor and measuring device - Google Patents

Description

  The present invention relates to a clip type voltage detection sensor capable of clipping (holding) a measurement target conductor, and a measuring device having this voltage detection sensor and capable of measuring the voltage of the measurement target conductor.

  As a measurement apparatus of this type, the applicant of the present application, in Patent Document 1 below, describes the voltage (inter-line voltage as AC voltage) between two electric paths as a measurement target conductor, the metal part (core) of the electric path Discloses a measuring device capable of measuring in a non-contact state (that is, in a non-metal contact state) without being in electrical contact with the sensor. This measuring apparatus includes at least two floating circuit units, as many main circuit units as the floating circuit units connected one-to-one (individually) to these floating circuit units, a calculation unit where each main circuit unit is connected, and And a display unit connected to the calculation unit. In this measuring apparatus, the floating circuit unit and the main circuit unit connected thereto constitute one voltage detection sensor which is not a clip type, but this voltage detection sensor measures (detects) the voltage of the electric path. The voltage data indicating the waveform of the voltage is output to the calculation unit. In addition, the calculation unit and the display unit are normally housed in one case to constitute a measuring device main body in the measuring device, and the calculation unit is configured to calculate a reference voltage (each of the reference voltages) based on voltage data output from each voltage detection sensor. The voltage of each electric path is measured with respect to the common reference voltage of the main body circuit portion of the voltage detection sensor, and the voltage (inter-line voltage) between each electric path is measured based on the measured voltage of each electric path. Display the voltage between lines on the display.

  Each floating circuit unit includes at least a guard electrode, a detection electrode, and a current-voltage conversion unit (current-voltage conversion circuit and integration circuit). In the floating circuit portion, the electric circuit such as the current-voltage conversion portion is covered by the guard electrode, and thus is shielded against external noise. The detection electrode to be capacitively coupled to the metal portion of the electrical path is disposed so that at least the surface facing the metal portion of the electrical path is exposed from the guard electrode.

  Further, a voltage (applied voltage) described later output from the main body circuit unit is applied to the guard electrode of the floating circuit unit. The applied voltage is a voltage controlled (feedback control) by the main body circuit unit so that the voltage value matches the voltage value of the voltage of the electric path. Further, in the floating circuit portion, the operating voltage generated by the main body circuit portion (for example, two voltages having the same absolute value but different polarities (operating power sources)) are floating with the applied voltage as a reference voltage An electric circuit such as a current-voltage converter that is supplied as a voltage (floating power supply) and configures a floating circuit operates with this operating voltage.

  In the floating circuit portion, in a state where the detection electrode is disposed opposite to the metal portion of the electric path and capacitively coupled to the metal portion of the electric path, the current-voltage conversion portion includes the metal portion of the electric path and the detection electrode Generates a voltage detection signal whose voltage value changes in proportion to the current value of the current flowing between (current flowing due to the potential difference between the circuit and the detection electrode), and an integration signal (circuit) of this voltage detection signal And a detection signal that changes in voltage value in proportion to the potential difference between the detection signal and the detection electrode, and outputs the integration signal to the main circuit.

  In this case, the circuit of the input stage of the current-voltage conversion unit (that is, the circuit of the input stage of the current-voltage conversion circuit) is configured using an operational amplifier, its inverting input terminal is connected to the detection electrode, and its non-inverting The input terminal is connected to the guard electrode. With this configuration, in the floating circuit portion, the detection electrode is defined to have the same voltage value as the applied voltage (reference voltage for the floating voltage) applied to the guard electrode. Therefore, the integration signal output to the main body circuit unit is a signal whose voltage value changes in proportion to the potential difference between the voltage of the electric path and the applied voltage.

  In addition, usually, the floating circuit portion is formed in a clip shape capable of sandwiching an electric path like a sensor for voltage measurement disclosed in Patent Document 2 below in order to enhance the workability of voltage measurement operation. The casing (generally formed in a clip shape having a sensor substrate storage portion and a measurement target wire pressing portion and configured such that these two members function as a pair of sandwiching portions sandwiching an electric path) Are housed and configured into a single voltage detection sensor as a whole. Further, the detection electrode is disposed at a portion sandwiching the electric path in the casing (specifically, the sensor substrate accommodating portion functioning as one sandwiching portion), and the guard electrode is the back surface of the detection electrode in the casing (detection electrode When the surface on the side of the measurement target wire pressing portion in the above is the front surface, the rear surface side of this surface is disposed.

  Note that the main circuit section is housed in the casing together with the floating circuit section, or the relay box separate from the casing (a box made of resin connected to the floating circuit section in the casing via a cable) It is possible to adopt a configuration in which it is housed inside, but in either configuration, one voltage detection sensor is configured together with the floating circuit portion. With the configuration in which the floating circuit portion is accommodated in the clip-like casing, even if the voltage detection sensor is released after the voltage detection sensor is pinched the electric path, the capacitive connection between the electric path and the detection electrode is maintained. Be done. For this reason, since it becomes possible to perform another work in the voltage measurement work with a vacant hand, it is possible to improve the workability.

  On the other hand, as described in Patent Document 1, the main body circuit unit includes, for example, a processing unit, a D / A conversion circuit, a boost circuit, a voltage detection circuit (voltmeter), a main power supply circuit and a DC / DC converter. ing. In the main circuit portion, the processing portion generates the above-mentioned potential difference (potential difference between the electric path and the detection electrode (applied voltage)) which is the source of the integration signal based on the integration signal output from the floating circuit portion. Is calculated, and voltage data corresponding to the calculated voltage value is output to the D / A conversion circuit. The D / A conversion circuit generates an analog signal of a voltage value indicated by the voltage data, and the booster circuit generates an applied voltage by boosting the analog signal.

  In the voltage detection sensor provided with the floating circuit unit and the body circuit unit having such a configuration, the processing unit repeatedly executes the operation of calculating voltage data of the voltage value as described above and outputting it to the D / A conversion circuit. The applied voltage output from the booster circuit is made to match the voltage of the electric path. The voltage detection circuit generates a voltage measurement detection signal that changes in conjunction with the applied voltage by dividing the applied voltage (voltage matched to the voltage of the electric path) at a predetermined ratio. Output to the outside (calculation unit) of the voltage detection sensor. The voltage measurement detection signal may be output as it is as an analog signal, but in the present example, as described above, the voltage measurement detection signal is converted into voltage data indicating the voltage waveform of the voltage measurement detection signal and output. . Further, although not described in Patent Document 1, when the voltage detection sensor having the floating circuit portion and the main body circuit portion detects a voltage of a known reference voltage value (reference amplitude) of the electric path, this reference An adjustment circuit for adjusting the amplitude of the voltage measurement detection signal is provided in the main circuit portion so that the voltage measurement detection signal is output to the outside at a prescribed voltage value (amplitude) corresponding to the voltage value. Is possible.

JP, 2010-25918, A (page 6-16, FIG. 1-9) JP-A-2014-44168 (page 5-6, FIG. 1-6)

  However, the above-described voltage detection sensor has the following problems to be improved. That is, when this voltage detection sensor is connected to the above-mentioned measurement device main body and used as a measurement device, it is checked in advance whether this voltage detection sensor operates normally or is outputted depending on the result of the check It may be necessary to adjust the amplitude of the voltage measurement detection signal. In this case, conventionally, for example, a test conductor such as a wire or rod-like electrode to which a reference voltage (AC voltage) having a known voltage value is applied is separately prepared, and the test conductor is sandwiched by a voltage detection sensor. By monitoring the measurement result output to the display unit of the measurement device body in the state, whether the voltage detection sensor operates normally (whether the voltage measurement detection signal is output or not, its amplitude is correct Or not) is checked.

  However, as described above, in the configuration in which the test conductor is separately prepared at the time of the operation check of the voltage detection sensor, there is a problem that it takes time and cost.

  The present invention has been made to solve such problems, and it is mainly intended to provide a voltage detection sensor capable of sufficiently reducing the labor and cost required for operation check, and a measuring device provided with this voltage detection sensor. To aim.

  In order to achieve the above object, the voltage detection sensor according to claim 1 is disposed in a casing having a pair of sandwiching portions capable of sandwiching a measurement target conductor, and one of the pair of sandwiching portions, A detection electrode capacitively coupled to the measurement target conductor, a first guard electrode disposed in the one pinch portion, and a second guard electrode disposed in the other pinch portion of the pair of pinch portions; The current flowing between the conductor to be measured and the detection electrode is disposed in the casing, one input terminal is connected to the detection electrode, and the other input terminal is connected to the first guard electrode. And a voltage according to the potential difference between the voltage to be measured of the conductor under measurement and the applied voltage applied to the first guard electrode based on the voltage signal. Value is incorrect A voltage detection unit that outputs a detection signal, and the voltage value of the detection signal is generated in the casing based on the detection signal and is applied to the first guard electrode based on the detection signal. A voltage generation unit operating in a first operation mode for controlling the voltage value of the applied voltage so as to approach zero, and a detection signal for measuring a voltage value that is proportional to the voltage value of the applied voltage while detecting the applied voltage And a voltage output unit that outputs the voltage to the outside, wherein the voltage generation unit generates an AC voltage of a predetermined reference amplitude and can output it as a reference AC voltage. A voltage generating circuit, and a disconnecting switch for disconnecting between the first guard electrode and the second guard electrode, and one of the selected one of the first operating mode and the second operating mode In the first operation mode, the output of the reference AC voltage from the reference voltage generation circuit is stopped, and the connection / disconnection switch is switched to the connection state, and the first guard is configured. An electrode and the second guard electrode are connected, and in the second operation mode, the connection switch is switched to the disconnection state to disconnect the first guard electrode and the second guard electrode and generate the reference voltage The output of the reference AC voltage from the circuit is started to output the reference AC voltage to the second guard electrode, and the applied voltage is generated based on the detection signal and applied to the first guard electrode. The voltage value of the applied voltage is controlled such that the voltage value of the detection signal approaches zero.

  The voltage detection sensor according to claim 2 is the voltage detection sensor according to claim 1, wherein the voltage output unit detects the applied voltage and divides the voltage at a predetermined ratio to output as a divided voltage. The circuit includes: a circuit; and an amplifier circuit that amplifies the divided voltage with a set amplification factor and outputs the amplified voltage as the voltage measurement detection signal, and the voltage generation unit measures the voltage in the second operation mode. While detecting the amplitude of the detection signal, the amplification factor of the amplification circuit is set such that the amplitude becomes a predetermined reference output amplitude.

  The voltage detection sensor according to claim 3 is the voltage detection sensor according to claim 2, wherein the voltage generation unit is configured to be operable in a third operation mode in addition to the first operation mode and the second operation mode. In the third operation mode, the output of the applied voltage is stopped, the disconnection switch is shifted to the connection state, and the output of the reference AC voltage in the reference voltage generation circuit is started, and the reference is generated. The voltage value of the divided voltage output from the voltage output unit that detects the reference AC voltage instead of the applied voltage while outputting an AC voltage to the first guard electrode and the second guard electrode The amplitude of the reference AC voltage to be measured based on the amplitude is adjusted to match the reference amplitude.

  The measurement apparatus according to claim 4 measures the voltage to be measured based on the voltage detection sensor according to any one of claims 1 to 3 and the detection signal for voltage measurement output from the voltage detection sensor. And an apparatus body.

  According to the voltage detection sensor of claim 1 and the measurement apparatus of claim 4, when the voltage generation unit is in the second operation mode, the reference alternating current of the second guard electrode functioning as a pseudo measurement target conductor A voltage measurement detection signal having an amplitude (reference output amplitude) proportional to the reference amplitude of the voltage can be output, whereby the operation check of the voltage detection sensor based on the voltage measurement detection signal output from the voltage detection sensor As a result, the operator does not need to separately prepare a signal generator or the like, so that the time and cost required for the operation check can be sufficiently reduced. ,

  According to the voltage detection sensor of claim 2 and the measurement apparatus of claim 4, when the voltage generation unit is in the second operation mode, detection for voltage measurement is performed while executing the same operation as in the first operation mode. Since the voltage output unit is adjusted so that the amplitude becomes the reference output amplitude while detecting the amplitude of the signal, the adjustment of the amplitude of the voltage measurement detection signal can be automated.

  According to the voltage detection sensor of claim 3 and the measuring apparatus of claim 4, from the voltage output unit which operates in the third operation mode and detects the reference AC voltage instead of the applied voltage. Since the amplitude of the reference AC voltage measured based on the voltage value of the output divided voltage can be exactly matched to the reference amplitude, the operation check of the voltage detection sensor can be performed more accurately.

It is a block diagram (a schematic diagram about the clip part 11) for demonstrating the structure of the measuring apparatus 1. FIG. It is a block diagram of voltage detection sensor 2 (3) of FIG.

  Hereinafter, embodiments of a voltage detection sensor and a measuring device will be described with reference to the attached drawings.

  First, the configuration of the measuring device 1 as the measuring device shown in FIG. 1 will be described with reference to the drawings.

  As shown in FIG. 1, this measuring device 1 includes, as an example, voltage detecting sensors 2 and 3 as voltage detecting sensors, and a measuring device main body 4 to which each of the voltage detecting sensors 2 and 3 is connected. It is configured as a voltage measuring device capable of measuring a potential difference (line voltage) Vlv between two electric paths 5 and 6 as an example of a measurement target conductor clipped (sandwiched) by the sensors 2 and 3.

  As shown in FIGS. 1 and 2, each of the voltage detection sensors 2 and 3 has the same configuration, and via the clipped measurement target conductor (electrical path 5 or electrical path 6) and the coupling capacitance (capacitance Ca or capacitance Cb) The capacitive coupling is performed, and the voltage to be measured of the conductor to be measured (the voltage V1a of the electric path 5 and the voltage V1b of the electric path 6. When the voltages V1a and V1b are not distinguished, it is also referred to as "voltage V1"). The voltage measuring detection signal S6, which will be described later, has a voltage value proportional to the voltage value of V.sub.5, and has the same function as outputting the measuring signal S.sub.6 to the measuring apparatus main body 4 via the connection connector 13 described below. Therefore, the configuration of each of the voltage detection sensors 2 and 3 will be described by taking the voltage detection sensor 2 as an example.

  The voltage detection sensor 2 includes, as an example, a clip portion 11, a relay box 12, and a connector 13 as shown in FIG. 1, and the connector 13 is disposed on the panel surface of the measuring apparatus main body 4 or the like described later. By being connected to the input connector 52, it is configured to be connectable to the measuring device main body 4. The clip portion 11 and the relay box 12 constitute a casing as a whole, and are connected by a multi-core cable 14 as an example. Further, the relay box 12 and the connection connector 13 are connected by another multicore cable 15 as an example. In addition, the structure which accommodates the below-mentioned each component arrange | positioned in the relay box 12 in the clip part 11 is also employable. In this configuration, the relay box 12 can be omitted, and the connection connector 13 is connected to the clip portion 11 via a multicore cable.

  The clip portion 11 includes a pair of clip pieces 21 and 31 formed of an electrically insulating material such as a synthetic resin material, as shown in a schematic view shown in FIG. Is configured to be able to clip the conductor to be measured.

  Specifically, one end of the clip piece 21 is formed at the pinching portion 22 and the other end is formed at the pinching portion 23 as one example, and one end of the clip piece 31 is formed at the pinching portion 32 as one example. The other end is formed in the knob 33 while being formed. Further, the clip pieces 21 and 31 center around the pivot axis A defined at the central portion of each other in a state in which the pinching portions 22 and 32 face each other and the pinching portions 23 and 33 face each other. It is connected rotatably as. Further, a torsion spring (not shown) is disposed in each of the clip pieces 21 and 31 to always bias the clip pieces 21 and 31 in the direction in which the pinching portions 22 and 32 approach each other. With this configuration, the clip portion 11 is configured to be able to clip the conductor to be measured (in this example, the electric path 5 or the electric path 6) between the clip portion 22 of the clip piece 21 and the clip portion 32 of the clip piece 31 ing.

  Further, a guard electrode (second guard electrode) 26 is disposed in the sandwiching portion 22 (the other sandwiching portion) of the clip piece 21. The guard electrode 26 is formed of, for example, a flat metal plate, and is connected to a first switch 41 d described later in the relay box 12 via the multicore cable 14 as shown in FIG. 2.

  In addition, a detection electrode 34 is disposed in the pinching portion 32 (one pinching portion) of the clip piece 31. The detection electrode 34 is formed of, for example, a flat metal plate, and is pinched so that capacitive coupling with the measurement target conductor clipped between the pair of pinching portions 22 and 32 is performed in a good state. 32 is disposed in the vicinity of the surface facing the sandwiching portion 22 (the contact surface with the conductor to be measured; the upper surface in FIG. 1).

  Further, in the clip piece 31 on which the detection electrode 34 is disposed, a voltage detection unit 35 configured of a plurality of electronic components (not shown) mounted on a substrate (not shown) is disposed. Further, in the clip piece 31, a guard electrode (first guard electrode) is provided between the detection electrode 34 and the voltage detection unit 35 and the non-facing surface (lower surface in FIG. 1) of the clip piece 31 with the clip piece 21. ) 36 are provided. The guard electrode 36 is formed of, for example, a flat metal plate, and has a width that covers the entire detection electrode 34 and the voltage detection unit 35 when the clip piece 31 is viewed from the non-facing surface side. There is. Further, as shown in FIG. 2, the guard electrode 36 is a booster circuit 41 b described later in the relay box 12 via the multi-core cable 14 (an output terminal (not shown for the applied voltage V4 described later in the booster circuit 41 b)). It is connected to the.

  Although it is preferable that the guard electrode 36 be formed so as to cover the whole of the detection electrode 34 and the voltage detection unit 35 as in this example, if it is formed so as to cover at least the detection electrode 34. Alternatively, the voltage detection unit 35 may not be covered. Further, when the substrate on which the electronic component constituting the voltage detection unit 35 is mounted is a multilayer substrate, a reference voltage for an operation power supply (positive voltage Vf + and negative voltage Vf−) described later supplied to the electronic component The ground layer of the substrate to which G is applied may be used as a guard electrode.

  In the clip unit 11 configured as described above, when the detection target conductor is clipped between the pair of sandwiching portions 22 and 32, the detection electrode 34 capacitively couples with the measurement target conductor in a good state. On the other hand, when the detection electrode 34 does not clip the conductor to be measured between the pair of sandwiching portions 22 and 32 (that is, when the sandwiching portions 22 and 32 are in contact with each other), the guard electrode 26 When separated from the guard electrode 36, it is capacitively coupled to the opposing guard electrode 26.

  As an example, as shown in FIG. 2, the voltage detection unit 35 includes a current / voltage conversion circuit 35a, an integration circuit 35b, and an isolator (insulation circuit) 35c, and is a positive voltage supplied from the relay box 12 through the multicore cable 14. The voltage Vf + and the negative voltage Vf− (all are floating voltages with the applied voltage V4 as a reference voltage G and are operated by an operation power supply (floating power supply) for the voltage detection unit 35). The applied voltage V4 to be the reference voltage G in the voltage detection unit 35 is a voltage output from the booster circuit 41b in the relay box 12, and as described above, the voltage V4 in the clip piece 31 via the multicore cable 14 is The voltage is applied to the guard electrode 36. In the clip portion 11, as shown in FIG. 1, the detection electrode 34 is shown in FIGS. 1 and 2 in a state in which the conductor to be measured (the electric path 5 in the figure) is held between the sandwiching portions 22 and 32 as shown in FIG. The guard electrode 26 in the sandwiching portion 22 and the guard electrode 36 in the sandwiching portion 32 are sandwiched. With this configuration, when the guard electrode 26 is connected to the guard electrode 36, occurrence of a situation in which the detection electrode 34 capacitively couples with another conductor other than the measurement target conductor (electrical path 5) 26 and 36 make it possible to reduce significantly.

  In the current-voltage conversion circuit 35a, as shown in FIG. 2, the inverting input terminal as one input terminal is connected to the detection electrode 34, and the non-inverting input terminal as the other input terminal is the reference voltage G (even if the applied voltage V4. Specified (specifically, specified as the reference voltage G by being connected to the guard electrode 36 directly or through a resistor), and a feedback resistance is connected between the inverting input terminal and the output terminal. And an operational amplifier (op amp). Therefore, the detection electrode 34 is regulated to the same voltage as the reference voltage G. With this configuration, as shown in FIG. 2, the current-voltage conversion circuit 35 a has a potential difference between the voltage (AC voltage) V1 a of the electric path 5 as the measurement target conductor and the voltage of the detection electrode 34 (that is, the reference voltage G). Due to Vdi, the current I1a flowing between the electric path 5 and the detection electrode 34 is detected via the coupling capacitance Ca between the electric path 5 and the detection electrode 34, and is converted into a voltage signal S1 and output.

  The integration circuit 35b integrates the voltage signal S1 to output a detection signal S2 whose voltage value changes in accordance with the potential difference Vdi. The isolator 35c receives the detection signal S2 and is electrically isolated from the detection signal S2 (as an example, the amplitude is proportional to the amplitude of the detection signal S2 and has the same phase as the detection signal S2). A voltage signal, that is, a voltage signal whose voltage value changes in accordance with the potential difference Vdi in the same manner as the detection signal S2, is output to the relay box 12 via the multicore cable 14.

  With the above configuration, the clip portion 11 of the voltage detection sensor 2 electrically connects the detection electrode 34 to the metal portion of the electric path 5 (for example, when the electric path 5 is formed of a coated electric wire) as the conductor to be measured The voltage V1a of the electric path 5 is detected in a non-contact state (that is, a metal non-contact state) without being brought into contact with the relay box 12, and a detection signal S3 whose voltage value changes according to the potential difference Vdi It is possible to output.

  As shown in FIG. 2, the relay box 12 includes, as an example, a voltage generation unit 41, a voltage output unit 42, and a DC / DC converter (hereinafter, also simply referred to as a "converter") 43. It is accommodated and comprised in the box main body 44 (refer FIG.1, 2) formed with the material which has electrical insulation, such as a resin material. Each component such as voltage generation unit 41 disposed in relay box 12 is supplied with positive voltage Vc + and negative voltage Vc− (all of which are reference voltage G1 supplied from measurement apparatus main body 4 via multi-core cable 15). Operates at a voltage based on The reference voltage G1 is a reference voltage in the measuring device main body 4, and when the measuring device main body 4 is grounded, it is defined as a voltage (ground voltage) of the ground.

  Specifically, the voltage generation unit 41 includes a processing circuit 41a, a booster circuit 41b, a reference voltage generation circuit 41c, a first switch 41d, a second switch 41e, and a third switch 41f (disconnection switch).

  The processing circuit 41a includes a CPU, an A / D converter, a D / A converter, etc. (all not shown) as an example, and outputs a drive signal Sd1 for driving the booster circuit 41e from the clip unit 11. Signal generation processing that generates the amplitude (voltage value) by changing the amplitude (voltage value) according to the voltage value of the detection signal S3, and changes the amplitude (voltage value) of the drive signal Sd2 for driving the reference voltage generation circuit 41c as necessary. Reference signal generation processing to generate the first switch 41d, the second switch 41e, and the third switch 41f independently of each other (switching to any one of the connection state and the disconnection state) switching processing of the voltage output unit 42 Gain setting processing for setting (or adjusting) the gain (amplification factor) of the amplification circuit 42b described later, and application based on the voltage value of the divided voltage V5 output from the voltage output unit 42 Performing a voltage measurement process for measuring the voltage value of the voltage measurement detection signal S6 outputted from the measurement and the voltage output unit 42 of the voltage value of the pressure V4 and the reference alternating voltage V6.

  The booster circuit 41b boosts the input drive signal Sd1 (boosts the voltage at a predetermined constant boosting rate) to generate an applied voltage V4, and outputs the generated applied voltage V4 to the first switch 41d. The reference voltage generation circuit 41c generates a reference AC voltage V6 (AC voltage of a predetermined reference amplitude) by boosting the input drive signal Sd2 (step up the voltage at a predetermined constant boosting rate). The reference AC voltage V6 is output to the second switch 41e. With this configuration, the processing circuit 41a changes the amplitude (voltage value) of the applied voltage V4 output from the booster circuit 41b by changing the amplitude (voltage value) of the drive signal Sd1 in the above-described signal generation process. Is possible. Further, the processing circuit 41a adjusts the amplitude (voltage value) of the drive signal Sd2 in the above-described reference signal generation process to obtain the reference amplitude (voltage value) of the reference AC voltage V6 output from the reference voltage generation circuit 41c. It is possible to adjust.

  One end of the first switch 41d is connected to the output terminal (not shown) of the applied voltage V4 in the booster circuit 41b, and the other end is connected to the guard electrode 36 of the clip portion 11 via the multicore cable 14 There is. With this configuration, when the first switch 41d is switched to the connected state by the processing circuit 41a, the first switch 41d applies the applied voltage V4 output from the booster circuit 41b to the guard electrode 36 via the multicore cable 14 to process the processing circuit. When switched to the disconnected state by 41a, the output of the applied voltage V4 to the multicore cable 14 is stopped.

  The second switch 41 e has one end connected to the output terminal (not shown) of the reference AC voltage V 6 in the reference voltage generation circuit 41 c and the other end connected to the guard electrode 26 of the clip portion 11 via the multicore cable 14. It is connected. With this configuration, when the second switch 41e is switched to the connected state by the processing circuit 41a, the reference AC voltage V6 output from the reference voltage generation circuit 41c is used as a guard voltage at the guard electrode 26 via the multicore cable 14. When applied as Vg and switched to the disconnected state by the processing circuit 41a, the output of the reference AC voltage V6 to the multicore cable 14 is stopped.

    One end of the third switch 41f is connected to the other end of the first switch 41d, and the other end is connected to the other end of the second switch 41e. With this configuration, the third switch 41 f can connect and disconnect the guard electrodes 26 and 36 of the clip portion 11 via the multicore cable 14. Specifically, when the third switch 41 f is switched to the connected state by the processing circuit 41 a, the third switch 41 f electrically connects the guard electrodes 26 and 36 of the clip unit 11 via the multicore cable 14 to process the processing circuit 41 a. When the state is switched to the cut state by this, the electrical connection state of each guard electrode 26, 36 is released (electrically separated (disconnected)).

  Further, in the voltage generation unit 41 of the present example, the processing circuit 41a is configured to be operable in the following three operation modes (a first operation mode, a second operation mode, and a third operation mode). The operation mode of the processing circuit 41a is configured to be switchable by the mode switching signal Sm input to the processing circuit 41a. The mode switching signal Sm is provided with a switch for mode switching which outputs the mode switching signal Sm in the relay box 12 and is output from the switch to the processing circuit 41 a or a switch for switching the mode. Are arranged in the clip unit 11 and output from the switch to the processing circuit 41a through the multi-core cable 14 or a switch for mode switching is arranged in the measuring apparatus main body 4 It is possible to adopt any one of the configurations to be output to the processing circuit 41 a via the core cable 15.

  First, the first operation mode is an operation mode for causing the voltage detection sensor 2 to execute a measurement operation for detecting the voltage V1a of the electric path 5 clipping between the pair of sandwiching portions 22 and 32. In the first operation mode, the processing circuit 41a performs switching processing to switch the first switch 41d and the third switch 41f to the connection state, and switches the second switch 41e to the disconnection state. That is, the processing circuit 41a disconnects the guard electrode 26 of the clip unit 11 from the reference voltage generation circuit 41c, applies the applied voltage V4 output from the booster circuit 41b to the guard electrode 36 of the clip unit 11, and It switches to the state which can be applied to 11 guard electrodes 26 as guard voltage Vg.

  Further, in the first operation mode, the processing circuit 41a detects the voltage value of the detection signal S3 output from the clip unit 11 in this switching state, and generates the drive signal Sd1 based on the detected voltage value. At the same time, a signal generation process is performed to control the voltage value of the drive signal Sd1 so that the voltage value of the detection signal S3 approaches zero. Therefore, in the first operation mode, the voltage generation unit 41 controls the voltage value of the applied voltage V4 such that the voltage value of the detection signal S3 (that is, the potential difference Vdi described above) approaches zero, that is, the applied voltage An operation is performed to match the voltage value of V4 with the voltage of the measurement target conductor (in this example, the voltage V1a of the electric path 5). Thus, the voltage measurement detection signal S6 output from the voltage output unit 42 when the processing circuit 41a is operating in the first operation mode has a voltage value equal to that of the applied voltage V4 (that is, It becomes a state of being output as a signal of a voltage value proportional to the voltage value of the voltage V1a, and the voltage value of the voltage V1a can be measured on the side of the measuring device body 4 based on the voltage measurement detection signal S6.

  Further, in the second operation mode, when the voltage detection sensor 2 is detecting the AC voltage of the conductor generating the AC voltage of the above reference amplitude (the same amplitude as the reference AC voltage V6), The voltage detection sensor is a gain setting process for setting the gain of the voltage measurement detection signal S6 in the voltage output unit 42 so that the voltage measurement detection signal S6 is output from the detection sensor 2 at a predetermined reference output amplitude. It is an operation mode for making 2 execute.

  In the second operation mode, the measurement target conductor (electrical path 5) is not clipped between the pair of sandwiching portions 22 and 32, that is, the detection electrode 34 in the sandwiching portion 32 is the guard electrode 26 in the sandwiching portion 22 and It is carried out in a state in which capacitive coupling is possible (a state in which the guard electrode 26 can be a pseudo measurement target conductor for the detection electrode 34). In the second operation mode, the processing circuit 41a first performs switching processing to switch the first switch 41d and the second switch 41e to the connection state, and switches the third switch 41f to the disconnection state. That is, the processing circuit 41a separates the guard electrode 26 of the clip unit 11 from the guard electrode 36, and the applied voltage V4 output from the booster circuit 41b is applied only to the guard electrode 36, and the reference output from the reference voltage generation circuit 41c. The AC voltage V6 is switched to a state where it is applied only to the guard electrode 26 as the guard voltage Vg.

  Next, in the second operation mode, the processing circuit 41a executes the reference signal generation processing to generate the drive signal Sd2 and outputs the drive signal Sd2 to the reference voltage generation circuit 41c, whereby the reference voltage reference from the reference voltage generation circuit 41c. An alternating voltage V6 is output and applied to the guard electrode 26 as a guard voltage Vg. The processing circuit 41a detects the voltage value of the detection signal S3 output from the clip unit 11 together with the reference signal generation processing, and generates the drive signal Sd1 based on the detected voltage value, while detecting the detection signal. A signal generation process is performed to control the voltage value of the drive signal Sd1 such that the voltage value of S3 approaches zero. The potential difference Vdi in the above-described first operation mode is the potential difference between the applied voltage V4 and the reference AC voltage V6 in this second operation mode. Therefore, the potential difference Vdi in the second operation mode is a potential difference between the applied voltage V4 and the reference AC voltage V6.

  Therefore, in the second operation mode, the voltage generation unit 41 performs the signal generation processing to cause the voltage value of the detection signal S3 (that is, the potential difference Vdi described above) to approach zero, the voltage of the applied voltage V4. Operation of controlling the value (operation of controlling the voltage value of the applied voltage V4 in the same manner as in the first operation mode), that is, the reference applied to the guard electrode 26 functioning as a pseudo measurement target conductor An operation is performed to match the voltage value of the applied voltage V4 with the voltage value of the AC voltage V6.

  Further, in the second operation mode, the processing circuit 41a performs the same operation as in the first operation mode as described above (as described above) to set the voltage value of the applied voltage V4 to the voltage value of the reference AC voltage V6. In the state where they coincide with each other, voltage measurement processing is executed, and the voltage measurement detection signal S6 output from the voltage output unit 42 (specifically, the third amplification circuit 42b described later of the voltage output unit 42) The gain setting process is performed while measuring the voltage value (amplitude), and the gain of the amplification circuit 42b, which will be described later, is set such that the amplitude of the voltage measurement detection signal S6 being measured becomes a predetermined reference output amplitude. Set (adjust).

  The third operation mode is an operation mode for causing the voltage detection sensor 2 to automatically adjust the amplitude of the reference AC voltage V6 output from the reference voltage generation circuit 41c to a predetermined reference amplitude. In the third operation mode, the processing circuit 41a executes the switching process to switch the first switch 41d to the disconnection state and to switch the second switch 41e and the third switch 41f to the connection state. As a result, the voltage output unit 42 shifts to a state of detecting the reference AC voltage V6 instead of the applied voltage V4.

  Further, in the third operation mode, the processing circuit 41a executes the reference signal generation processing to generate the drive signal Sd2 and outputs the drive signal Sd2 to the reference voltage generation circuit 41c, whereby the reference amplitude from the reference voltage generation circuit 41c (initial setting The reference AC voltage V6 is output. In this state, the processing circuit 41a executes the voltage measurement process and outputs the voltage value of the divided voltage V5 output from the voltage output unit 42 (specifically, the voltage dividing circuit 42a described later of the voltage output unit 42) When the amplitude of the reference AC voltage V6 being measured deviates from the original reference amplitude while measuring the amplitude of the reference AC voltage V6 based on the measured voltage value of the divided voltage V5 while measuring the amplitude) The amplitude of the generated drive signal Sd2 is adjusted to match the amplitude of the reference AC voltage V6 with a predetermined reference amplitude (the original reference amplitude).

  Thus, when the processing circuit 41a generates the drive signal Sd2 for outputting the reference AC voltage V6 of the reference amplitude from the reference voltage generation circuit 41c with the amplitude (voltage value) of the initial setting, for example, in the processing circuit 41a. When the amplitude of the reference AC voltage V6 output from the reference voltage generation circuit 41c deviates from the original reference amplitude due to the variation of the D / A converter and the electronic components constituting the reference voltage generation circuit 41c. Even in this case, the operation in the third operation mode makes it possible to output the reference AC voltage V6 from the reference voltage generation circuit 41c with the original reference amplitude. From the above, first, the processing circuit 41a is operated in the third operation mode to make the amplitude of the reference AC voltage V6 exactly match the reference amplitude, and then the processing circuit 41a is operated in the second operation mode to output voltage Preferably, the gain in section 42 is set.

  As an example, as shown in FIG. 2, the voltage output unit 42 includes a voltage dividing circuit 42a and an amplifier circuit 42b, and detects an applied voltage V4 and also applies the applied voltage V4 in the first operation mode and the second operation mode. The voltage measurement detection signal S6 having a voltage value proportional to the voltage value of V.sub.1 is generated and output to the outside (in this example, to the measuring apparatus main body 4 via the multicore cable 15 and the connector 13). On the other hand, in the third operation mode, voltage output unit 42 detects reference AC voltage V6 instead of applied voltage V4 and detects voltage measurement detection signal S6 having a voltage value proportional to the voltage value of reference AC voltage V6. Generate and output to the outside

  The voltage dividing circuit 42a is configured, for example, by connecting a plurality of resistors in series, and one end thereof is connected to one end of the third switch 41f (also connected to the other end of the first switch 41d), and the other end is The reference voltage G1 is defined. With this configuration, the voltage dividing circuit 42a generates the application voltage V4 generated based on the reference voltage G1 and the connection state of the switches 41d to 41f of the reference AC voltage V6 generated based on the reference voltage G1. A divided voltage V5 is output by dividing one of the selected voltages at a predetermined ratio. The amplification circuit 42b amplifies the input divided voltage V5 by the gain set by the processing circuit 41a, and outputs the amplified divided voltage V5 to the multicore cable 15 as a voltage measurement detection signal S6.

  Converter 43 operates on the basis of positive voltage Vc + and negative voltage Vc− to operate the primary winding of this transformer, based on an insulated transformer having a primary winding and a secondary winding electrically isolated from each other as an example. A reference voltage G1 on the primary side, a positive voltage Vc +, and a negative voltage, including a drive circuit to be driven and a DC conversion unit (both not shown) for rectifying and smoothing an AC voltage induced in the secondary winding of the transformer It is configured as an isolated power supply that outputs a positive voltage Vf + and a negative voltage Vf- as a floating voltage based on the applied voltage V4 from the secondary side electrically isolated from Vc-. The positive voltage Vf + and the negative voltage Vf− are DC voltages having substantially the same absolute value and different polarities, and are supplied to the clip unit 11 through the multicore cable 14.

  As an example, as shown in FIG. 1, the measuring device body 4 includes a casing 51 and a plurality of input connectors disposed on a panel surface (not shown) of the casing 51 (in the present example, two input connectors 52 a and 52 b Hereinafter, when not particularly distinguished, it is also referred to as the input connector 52), the power supply unit 53 and the processing unit 54 disposed in the casing 51, and the display unit disposed on the panel surface of the casing 51 (for example, liquid crystal display device Etc.) equipped with 55.

  Each input connector 52 includes a plurality of contacts, some of which are connected as ground contacts to the reference voltage G1 in the measuring apparatus body 4, and other parts of them as positive power contacts, Of the positive voltage Vc + and the negative voltage Vc- described later output from the power supply unit 53, the positive voltage Vc + is applied, the other part thereof is applied as the negative power supply contact, and the negative voltage Vc- is applied. A part of the voltage detection detection signal S6 is input as a detection voltage contact.

  The power supply unit 53 includes, for example, a battery, a converter, and the like, and operates on each component in the measuring apparatus main body 4 (in the present example, based on the reference voltage G1 in the measuring apparatus main body 4). Power supply for operation of positive voltage Vc + and negative voltage Vc- which are DC voltages of almost the same absolute value and different in polarity mutually different. Note that depending on the specification of each component, only positive voltage Vc + may be generated. . Further, the operation voltages (in this example, the positive voltage Vc + and the negative voltage Vc−) and the reference voltage G1 are applied to the specified contacts in each input connector 52 as described above.

  As an example, the processing unit 54 is configured to include an A / D converter and a computer, and converts the voltage measurement detection signal S6 input from each input connector 52 into digital data indicating the instantaneous value, and this digital Based on the data, measurement processing is performed to measure the voltages V1a and V1b of the electric paths 5 and 6 clipped by the voltage detection sensors 2 and 3 connected to the input connectors 52, respectively. Further, in the measurement process, the processing unit 54 measures a potential difference (line voltage) Vlv between the electric paths 5 and 6 based on the measured both voltages V1a and V1b to obtain the voltages V1a and V1b and the potential difference Vlv. At least the potential difference Vlv is output to the display unit 55.

  Next, the operation of the measuring device 1 will be described along with the operation of each of the voltage detection sensors 2 and 3. First, an operation when measuring a potential difference Vlv between the two electric paths 5 and 6 (hereinafter, also referred to as a line voltage Vlv) will be described.

  First, as shown in FIG. 1, the connection connectors 13 of the voltage detection sensors 2 and 3 are connected to the input connectors 52 of the measuring device body 4. Due to the connection to the measuring device main body 4, the voltage detecting sensors 2 and 3 receive operating voltages (positive voltage Vc + and negative voltage Vc− based on the reference voltage G1 from the measuring device main body 4 via the multicore cable 15). Is supplied, and the voltage generation unit 41, the voltage output unit 42 and the converter 43 in each of the relay boxes 12 of the voltage detection sensors 2 and 3 start operation. In addition, the positive voltage Vf + and the negative voltage Vf− (a floating power supply that uses the applied voltage V4 as a reference voltage G) output from the converter 43 that has started operation in this way are voltage detection sensors via the multicore cable 14 The voltage is supplied to each of the two or more clip units 11 and the voltage detection unit 35 in each of the clip units 11 starts operation.

  In this state, before clipping the corresponding electric paths 5 and 6 by the clip portions 11 of the voltage detection sensors 2 and 3, first, the operator operates the mode switching switch to set the voltage detection sensors 2 and 3 to each other. The mode switching signal Sm for operating in the third operation mode is input to the processing circuit 41 a of the voltage generation unit 41 in each of the relay boxes 12. At this time, each of the voltage detection sensors 2 and 3 starts an operation to make the amplitude of the reference AC voltage V6 output from the reference voltage generation circuit 41c of the voltage generation unit 41 exactly match the reference amplitude.

  Specifically, in the voltage detection sensors 2 and 3, the processing circuit 41a executes the operation in the third operation mode described above, and the reference AC voltage V6 output from the reference voltage generation circuit 41c is output from the voltage output unit 42. In order to be able to detect, switching processing is performed to switch the first switch 41d to the disconnection state and to switch the second switch 41e and the third switch 41f to the connection state. Further, in this state, the processing circuit 41a causes the reference voltage generation circuit 41c to output the reference AC voltage V6 of the reference amplitude by executing the reference signal generation processing and outputting the drive signal Sd2 to the reference voltage generation circuit 41c. Let's do it. In this state, the processing circuit 41a executes a voltage measurement process to measure the voltage value (amplitude) of the divided voltage V5 output from the voltage dividing circuit 42a of the voltage output unit 42, and also measures the divided voltage V5. While the amplitude of the reference AC voltage V6 being measured deviates from the reference amplitude while adjusting the amplitude of the generated drive signal Sd2 while measuring the amplitude of the reference AC voltage V6 based on the voltage value of The amplitude of the reference AC voltage V6 is matched to a predetermined reference amplitude (the original reference amplitude).

  Further, next, before clipping the corresponding electric paths 5 and 6 by the clip portions 11 of the voltage detection sensors 2 and 3, the operator operates the mode switching switch to set each of the voltage detection sensors 2 and 3. A mode switching signal Sm for operating in the second operation mode is input to the processing circuit 41 a of the voltage generation unit 41 in the relay box 12. At this time, each of the voltage detection sensors 2 and 3 starts an operation to make the amplitude of the reference AC voltage V6 output from the reference voltage generation circuit 41c of the voltage generation unit 41 exactly match the reference amplitude.

  Specifically, in the voltage detection sensors 2 and 3, the processing circuit 41a executes the operation in the above-described second operation mode to separate the guard electrode 26 of the clip unit 11 from the guard electrode 36 and output it from the booster circuit 41b. The first switch 41d is set such that the applied voltage V4 to be applied is applied only to the guard electrode 36, and the reference AC voltage V6 output from the reference voltage generation circuit 41c is applied as the guard voltage Vg only to the guard electrode 26. The second switch 41 e is switched to the connected state, and the switching process to switch the third switch 41 f to the disconnected state is executed.

  Further, in this state, the processing circuit 41a executes the reference signal generation processing to generate the drive signal Sd2 and outputs the drive signal Sd2 to the reference voltage generation circuit 41c, whereby the reference AC voltage V6 of the reference amplitude is generated from the reference voltage generation circuit 41c. Are output to the guard electrode 26 as a guard voltage Vg. Further, the processing circuit 41a detects the voltage value of the detection signal S3 output from the clip unit 11, and generates the drive signal Sd1 based on the detected voltage value, and the voltage value of the detection signal S3 is zero. A signal generation process is performed to control the voltage value of the drive signal Sd1 so as to approach. By this signal generation processing, the voltage value of the applied voltage V4 is made to coincide with the voltage value of the reference AC voltage V6 of the guard electrode 26 functioning as a pseudo measurement target conductor.

  Further, the processing circuit 41a executes the voltage measurement process in the state where the voltage value of the applied voltage V4 is thus made to coincide with the voltage value of the reference AC voltage V6, and the voltage output from the voltage output unit 42 Gain setting processing is performed while measuring the voltage value (amplitude) of the measurement detection signal S6, and amplification is performed such that the amplitude of the voltage measurement detection signal S6 being measured becomes a predetermined reference output amplitude. The gain of the circuit 42b is set (adjusted). Thereby, the voltage detection sensors 2 and 3 detect the AC voltage of the measurement target conductor to which the AC voltage of the reference amplitude is applied, and the amplitude of the voltage measurement detection signal S6 output becomes the reference output amplitude. To be adjusted automatically.

  Subsequently, the operator clips the electric path 5 with the clip portion 11 of the voltage detection sensor 2, clips the electric path 6 with the clip portion 11 of the voltage detection sensor 3, and operates the mode switching switch to detect voltage. A mode switching signal Sm for operating in the first operation mode is input to the processing circuit 41 a of the voltage generation unit 41 in each relay box 12 of the sensors 2 and 3. At this time, each of the voltage detection sensors 2 and 3 starts a measurement operation for detecting the voltages V1a and V1b of the electric paths 5 and 6 which are respectively clipped.

  Specifically, in the voltage detection sensors 2 and 3, the processing circuit 41a executes the operation in the above-described first operation mode to separate the guard electrode 26 of the clip unit 11 from the reference voltage generation circuit 41c, and The first switch is applied so that the applied voltage V4 output from 41b can be applied to the guard electrode 36 of the clip unit 11, and the applied voltage V4 can be applied as the guard voltage Vg to the guard electrode 26 of the clip unit 11. While switching 41 d and the 3rd switch 41 f to a connection state, the switching process which switches the 2nd switch 41 e to a disconnection state is performed.

  Thereby, in the voltage detection sensor 2, the detection electrode 34 in the clip portion 11 capacitively couples with the electric path 5, and the voltage detection portion 35 in the clip portion 11 receives the voltage V1 a of the electric path 5 and the voltage of the detection electrode 34 (that is, the voltage And generates a detection signal S3 whose voltage value changes in accordance with the potential difference Vdi with the reference voltage G), and outputs the detection signal S3 to the relay box 12. Also in the voltage detection sensor 3, the detection electrode 34 in the clip portion 11 capacitively couples with the electric path 6, and the voltage detection portion 35 in the clip portion 11 detects the voltage V1 b of the electric path 6 and the voltage of the detection electrode 34 (that is, A detection signal S3 whose voltage value changes in accordance with the potential difference Vdi with the reference voltage G) is generated and output to the relay box 12.

  In this state, in the voltage detection sensor 2, the processing circuit 41a in the relay box 12 detects the voltage value of the detection signal S3 output from the clip unit 11, and the drive signal Sd1 is output based on the detected voltage value. While generating, a signal generation process is performed to control the voltage value of the drive signal Sd1 such that the voltage value of the detection signal S3 (that is, the above-mentioned potential difference Vdi) approaches zero. Thus, in the state where the processing circuit 41a is operating in the first operation mode, the voltage value of the applied voltage V4 output from the booster circuit 41b is made to coincide with the voltage value of the voltage V1a of the electric path 5. Further, in the voltage detection sensor 2, the voltage output unit 42 in the relay box 12 detects the applied voltage V 4 and a voltage proportional to the voltage value of the applied voltage V 4 (that is, the voltage value of the voltage V 1 a of the electric path 5). A voltage measurement detection signal S6 of a value is generated and output to the measurement apparatus main body 4 through the multicore cable 15 and the connection connector 13.

  Further, in the voltage detection sensor 3 as well, the processing circuit 41a performs the same operation as the processing circuit 41a of the voltage detection sensor 2 described above, so the voltage value of the applied voltage V4 output from the booster circuit 41b is the voltage of the electric path 6. It is matched to the voltage value of V1b. Also in the voltage detection sensor 3, the voltage output unit 42 in the relay box 12 detects the applied voltage V 4 and a voltage proportional to the voltage value of the applied voltage V 4 (that is, the voltage value of the voltage V 1 b of the electric path 6) A voltage measurement detection signal S6 of a value is generated and output to the measurement apparatus main body 4 through the multicore cable 15 and the connection connector 13.

  In the measuring device body 4, the processing unit 54 executes the measuring process to measure the voltage V1a of the electric path 5 with reference to the reference voltage G1 based on the voltage measurement detection signal S6 from the voltage detection sensor 2 Based on the voltage measurement detection signal S6 from the detection sensor 3, the voltage V1b of the electric path 6 with reference to the reference voltage G1 is measured. Further, the processing unit 54 measures a potential difference (inter-line voltage) Vlv between the electric paths 5 and 6 based on the measured voltages V1a and V1b, and outputs the same to the display unit 55 for display. Thereby, the measurement of the potential difference (line voltage) Vlv between the electric paths 5 and 6 is completed. In this example, since the reference voltage G1 is defined to the voltage of the ground (ground voltage), the voltages V1a and V1b measured in this measurement process are determined on the basis of the voltage of the ground. It represents the voltage. Therefore, together with the measured potential difference (line voltage) Vlv, the voltages V1a and V1b may be output to the display unit 55 as the voltages of the electric paths 5 and 6, respectively. On the other hand, when the reference voltage G1 is in a floating state with respect to the voltage of the ground, the processing unit 54 displays only the potential difference (line voltage) Vlv between the electric paths 5 and 6 calculated from the voltages V1a and V1b.

  Further, in each of the voltage detection sensors 2 and 3, the voltage detected by the voltage output unit 42 in the state where the processing circuit 41 a is operating in any of the above-described second and third operation modes. A voltage measurement detection signal S6 having an amplitude proportional to the voltage value of (the applied voltage V4 or the reference AC voltage V6) is output to the measurement apparatus main body 4.

  Specifically, in the state where the processing circuit 41a is operating in the above-described third operation mode, the voltage output unit 42 detects the reference AC voltage V6, and measures voltage having an amplitude proportional to the voltage value. The detection signal S6 is output to the measuring device body 4. In this case, when the voltage detection sensors 2 and 3 (specifically, the reference voltage generation circuit 41c thereof) operate normally, the amplitude of the voltage measurement detection signal S6 is proportional to the reference amplitude of the reference AC voltage V6. And the reference output amplitude. Therefore, the processing unit 54 of the measuring device body 4 measures and measures an electrical parameter (for example, at least one of the amplitude, the average value, and the effective value) of the voltage measurement detection signal S6. An operation check is performed as to whether or not the voltage detection sensors 2 and 3 are operating normally in the third operation mode by comparing with threshold values stored in advance corresponding to the parameters.

  Generally, the electrical parameters measured when there is an abnormality in operation are lower than the electrical parameters measured when the voltage detection sensors 2 and 3 are operating normally. Therefore, the processing unit 54 sets the voltage detection sensors 2 and 3 based on the measured electric parameter and the threshold value by setting the minimum value of the electric parameter measured when operating normally as the threshold value. Can be checked whether it is operating normally in the third operating mode.

  The processing unit 54 outputs the result of the operation check on the voltage detection sensors 2 and 3 performed in this way to the display unit 55. Thereby, the operator can check whether the voltage detection sensors 2 and 3 can operate normally in the third operation mode based on the check result displayed on the display unit 55. .

  Moreover, in the state where the processing circuit 41a is operating in the above-described second operation mode, the voltage output unit 42 applies the state in which the voltage value matches the same voltage value as the reference AC voltage V6 as described above. The voltage V4 is detected, and a voltage measurement detection signal S6 having an amplitude proportional to the voltage value is output to the measurement apparatus main body 4. Therefore, when the voltage detection sensors 2 and 3 are operating normally, the amplitude of the voltage measurement detection signal S6 is a reference output amplitude proportional to the reference amplitude of the reference AC voltage V6. Therefore, by configuring the processing unit 54 of the measuring apparatus main body 4 to operate in the same manner as in the above-described third operation mode, the operator can check the display unit 55 based on the check result displayed on the display unit 55. It is possible to check whether the voltage detection sensors 2 and 3 can operate normally in the second operation mode (the operation mode including the same operation as the operation in the first operation mode as described above) .

  As described above, in the voltage detection sensors 2 and 3, the voltage generation unit 41 generates the boost circuit 41 b capable of outputting the applied voltage V 4 and generates the alternating voltage of the reference amplitude and generates the reference voltage capable of outputting as the reference alternating voltage V 6. A circuit 41c, and a third switch 41f connecting and disconnecting the guard electrode 26 and the guard electrode 36, and configured to be operable in one of the above-described first and second operation modes. It is done.

  Therefore, according to the voltage detection sensors 2 and 3 (specifically, according to the measurement device main body 4 to which the voltage detection sensors 2 and 3 are connected, that is, according to the measurement device 1), In the first operation mode, the voltage generation unit 41 stops the generation of the reference AC voltage V6 in the reference voltage generation circuit 41c (the output of the reference AC voltage V6 from the reference voltage generation circuit 41c) and the third switch 41f. In the connection state, when the guard electrodes 26 and 36 are connected, the applied voltage V4 is generated based on the detection signal S3 and applied to the guard electrodes 26 and 36 while the voltage value of the detection signal S3 (above By operating to control the voltage value of the applied voltage V4 so that the potential difference Vdi) approaches zero, in the voltage detection sensor 2, the voltage value of the voltage V1a of the electric path 5 and the voltage detection sensor 3 Can output a voltage measurement detection signal S6 of the voltage value proportional to the voltage value of the voltage V1b of path 6 to generate respectively, to the measuring device main body 4 via a multi-core cable 15 and the connector 13.

  Further, according to the voltage detection sensors 2 and 3 (specifically, according to the measurement device main body 4 to which the voltage detection sensors 2 and 3 are connected, that is, according to the measurement device 1), In the second operation mode, the voltage generation unit 41 switches the third switch 41 f to the disconnection state to separate the guard electrodes 26 and 36, and generates the reference AC voltage V 6 in the reference voltage generation circuit 41 c (reference voltage generation circuit The output of the reference AC voltage V6 from 41c is started and output to the guard electrode 26, and the applied voltage V4 is generated based on the detection signal S3 and applied to the guard electrode 36 while the voltage value of the detection signal S3 (above Operation of controlling the voltage value of the applied voltage V4 such that the potential difference Vdi) in the second operation mode of the present invention approaches zero, that is, the basis of the guard electrode 26 functioning as a pseudo measurement target conductor An operation to match the voltage value of the applied voltage V4 to the voltage value of the AC voltage V6 is executed, and the voltage measurement detection signal S6 of the amplitude (reference output amplitude) proportional to the reference amplitude of the reference AC voltage V6 is measured. Can be output to

  In addition, at this time, the voltage measurement detection signal of the reference output amplitude output from the voltage detection sensors 2 and 3 operating in the second operation mode is sent to the measurement device main body 4 to which the voltage detection sensors 2 and 3 are connected Since the operation check results for the voltage detection sensors 2 and 3 executed by the processing unit 54 in the measurement apparatus main body 4 are displayed based on S6, the operator can detect the voltage without separately preparing a signal generation device or the like. Whether the voltage detection sensors 2 and 3 are operating normally in the second operation mode (an operation mode including the same operation as the operation in the first operation mode) only with the sensors 2 and 3 and the measuring device body 4 It can check based on the check result. Therefore, according to the voltage detection sensors 2 and 3 and the measuring device 1 including the voltage detection sensors 2 and 3, it is not necessary to separately prepare a signal generation device or the like when checking the operation of the voltage detection sensors 2 and 3 Therefore, the time and cost required for the operation check can be sufficiently reduced.

  Further, in the voltage detection sensors 2 and 3, the voltage generation unit 41 detects the amplitude of the voltage measurement detection signal S6 in the above-described second operation mode, and detects the amplitude of the voltage measurement detection signal S6 in advance. The gain of the amplification circuit 42 b in the voltage output unit 42 is set to be Therefore, according to the voltage detection sensors 2 and 3 (specifically, according to the measurement device main body 4 to which the voltage detection sensors 2 and 3 are connected, that is, according to the measurement device 1), a signal generator and the like are separately prepared. It is possible to automatically execute adjustment of the amplitude of the own voltage measurement detection signal S6 (specifically, adjustment of the gain (amplification factor) of the amplification circuit 42b). That is, automatic adjustment of the voltage measurement detection signal S6 output from the voltage detection sensors 2 and 3 can be enabled.

  Further, in the voltage detection sensors 2 and 3, the voltage generation unit 41 is configured to be operable in the third operation mode in addition to the first operation mode and the second operation mode, and is applied in the third operation mode. The generation (output) of the voltage V4 is stopped, the third switch 41f is switched to the connection state, and the generation (output) of the reference AC voltage V6 in the reference voltage generation circuit 41c is started, and the guard electrodes 26 and 36 are generated. The amplitude of the reference AC voltage V6 measured based on the voltage value of the divided voltage V5 output from the voltage output unit 42 that detects the reference AC voltage V6 instead of the applied voltage V4 while outputting is used as the reference amplitude Adjust to match.

  Therefore, according to the voltage detection sensors 2 and 3 (specifically, according to the measurement device main body 4 to which the voltage detection sensors 2 and 3 are connected, that is, according to the measurement device 1), the reference in the second operation mode Since the amplitude of the reference AC voltage V6 output from the voltage generation circuit 41c can be exactly matched to the reference amplitude, the operation check in the second operation mode of the voltage detection sensors 2 and 3 can be performed more accurately. it can.

  In the above example, the voltage detection sensors 2 and 3 perform the operation of matching the voltage value of the applied voltage V4 with the voltage value of the reference AC voltage V6 during the operation in the second operation mode. The operation of setting the gain of the amplification circuit 42b in the voltage output unit 42 so that the amplitude of the voltage measurement detection signal S6 becomes the reference output amplitude in a state where the voltage value matches the voltage value of the reference AC voltage V6. Although the configuration to be performed is adopted, for example, when the gain adjustment of the amplification circuit 42b is unnecessary as in the case where the gain of the amplification circuit 42b can be accurately set in the adjustment operation at the time of manufacture, the voltage in the second operation mode The execution of the gain setting operation for the output unit 42 can be omitted.

  Further, in the above example, voltage detection sensors 2 and 3 are configured to be operable in the third operation mode in addition to the first and second operation modes, but the reference output from reference voltage generation circuit 41 c When the amplitude of the AC voltage V6 is sufficiently close to the reference amplitude with the initial setting, the third embodiment can be configured not to operate in the third operation mode.

  Further, as described above, even in the configuration in which the gain setting operation for the voltage output unit 42 is performed and the operation in the third operation mode is omitted, the processing unit 54 in the measuring apparatus main body 4 operates in the second operation mode. Since the operation check for the voltage detection sensors 2 and 3 can be executed based on the voltage measurement detection signal S6 output from the voltage detection sensors 2 and 3 to be displayed, the operator can generate a signal. It is possible to check whether the voltage detection sensors 2 and 3 are operating normally only with the voltage detection sensors 2 and 3 and the measuring device main body 4 without separately preparing a device or the like.

  Further, in the above example, the measuring apparatus 1 is a voltage measuring apparatus that measures the potential difference (line voltage) Vlv between the two electric paths 5 and 6 by connecting the two voltage detection sensors 2 and 3 to the measuring apparatus body 4 However, even in the configuration in which one voltage detection sensor (voltage detection sensor 2 or voltage detection sensor 3) is connected to the measuring apparatus main body 4, this one voltage detection sensor is added to the above-described first operation mode Can be operated in the second operation mode and the third operation mode, so the operation check that can be performed in the operation in the second operation mode and the third operation mode described above, and setting of the reference amplitude of the reference AC voltage V6 Also, the gain setting of the voltage output unit 42 can be automatically performed.

  Although the voltage detection sensors 2 and 3 employ the configuration in which the converter 43 is provided in the relay box 12, the present invention is not limited to this, and the configuration in which the converter 43 is provided in the clip portion 11 is employed. You can also In this configuration, converter 43 in clip unit 11 operates from relay box 12 through multi-core cable 14 based on positive voltage Vc + and negative voltage Vc− based on reference voltage G1, and A positive voltage Vf + and a negative voltage Vf- as floating voltages with reference to the applied voltage V4 are output from the next side and supplied to each component in the clip unit 11.

  Further, the measuring apparatus 1 may be configured to have a current measuring function in addition to the voltage measuring function, and further measure a resistance measuring function or electric power that measures resistance based on the measured voltage value and current value. It may be configured to include other measurement functions such as a power measurement function.

1 Measuring device
2, 3 voltage detection sensor
4 Measuring device body
5, 6 electric path (conductor to be measured)
DESCRIPTION OF SYMBOLS 11 Clip part 12 Relay box 26, 36 Guard electrode 34 Detection electrode 35 Voltage detection part 41 Voltage generation part 42 Voltage output part 42a Voltage division circuit 42b Amplifier circuit I1a Current S1 Voltage signal S3 Detection signal S6 Detection signal for voltage measurement V1a, V1b Voltage Vdi potential difference

Claims (4)

A casing having a pair of sandwiching portions capable of sandwiching a measurement target conductor;
A detection electrode disposed in one of the pair of sandwiching portions and capacitively coupled to the measurement target conductor;
A first guard electrode disposed in the one sandwiching portion;
A second guard electrode disposed in the other of the pair of sandwiching portions;
The current flowing between the conductor to be measured and the detection electrode is disposed in the casing, one input terminal is connected to the detection electrode, and the other input terminal is connected to the first guard electrode. And a voltage according to the potential difference between the voltage to be measured of the conductor under measurement and the applied voltage applied to the first guard electrode based on the voltage signal. A voltage detection unit that outputs a detection signal whose value changes;
The voltage value of the applied voltage is generated so that the voltage value of the detected signal approaches zero while being applied to the first guard electrode while generating the applied voltage based on the detected signal in the casing. A voltage generation unit operating in a first operation mode for controlling
A voltage detection sensor comprising: a voltage output unit that detects the applied voltage and generates a voltage measurement detection signal of a voltage value proportional to the voltage value of the applied voltage and outputs the detection signal to the outside;
The voltage generation unit generates a reference voltage with a reference voltage defined in advance and outputs the reference voltage as a reference voltage generation circuit, and a connection between the first guard electrode and the second guard electrode. And a switch, configured to be operable in one of the first and second operating modes selected from the first operating mode and the second operating mode,
In the first operation mode, the output of the reference AC voltage from the reference voltage generation circuit is stopped, and the disconnection switch is shifted to the connection state to set the first guard electrode and the second guard electrode. connection,
In the second operation mode, the connection switch is switched to the disconnection state to disconnect the first guard electrode and the second guard electrode and to start the output of the reference AC voltage from the reference voltage generation circuit. To output the reference AC voltage to the second guard electrode, generate the applied voltage based on the detection signal, and apply it to the first guard electrode so that the voltage value of the detection signal approaches zero. A voltage detection sensor that controls the voltage value of the applied voltage. The voltage output unit detects the applied voltage and divides the voltage at a predetermined ratio to output as a divided voltage, and the divided voltage is amplified by a set amplification factor to measure the voltage And an amplification circuit that outputs the detection signal as
The voltage generation unit detects the amplitude of the voltage measurement detection signal in the second operation mode, and sets the amplification factor of the amplification circuit such that the amplitude becomes a predetermined reference output amplitude. The voltage detection sensor according to claim 1.   The voltage generation unit is configured to be operable in a third operation mode in addition to the first operation mode and the second operation mode, and stops outputting the applied voltage in the third operation mode. The disconnection switch is shifted to the connection state, and the output of the reference AC voltage in the reference voltage generation circuit is started, and the reference AC voltage is output to the first guard electrode and the second guard electrode. The amplitude of the reference AC voltage measured based on the voltage value of the divided voltage output from the voltage output unit that detects the reference AC voltage instead of the applied voltage is made to coincide with the reference amplitude. The voltage detection sensor according to claim 2, wherein adjustment is performed.   A measuring apparatus comprising: the voltage detection sensor according to any one of claims 1 to 3; and a measuring apparatus main body which measures the voltage to be measured based on the detection signal for voltage measurement output from the voltage detection sensor. .

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