JP2021081240A - Electric signal detector - Google Patents

Abstract

To provide an inexpensive electric signal detector smaller in size and lighter in weight than a conventional one.SOLUTION: In an electric signal detector A1 which is arranged on a three-phase distribution line 9 and which detects an electric signal at a position it is arranged, three current sensors 1a, 1b, 1c are respectively arranged on distribution lines 91, 92, 93 of the three-phase distribution line 9 and output line current detection signals obtained by detecting line current flowing through the arranged distribution lines. Each of current sensors 1a, 1b, 1c is a coreless type and outputs a signal corresponding to magnetic field intensity generated around the distribution line as a line current detection signal.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electric signal detection device that detects various electric signals of a distribution line.

In order to measure various electrical characteristics such as current and voltage in the middle of the distribution line, an electric signal detection device has been developed that is placed in the middle of the distribution line and detects the current and voltage at the placed position. ing. An example of such an electric signal detection device is disclosed in Patent Document 1, for example, as a data collection device. The data collection device of Patent Document 1 detects a current flowing through a distribution line by using an instrument transformer.

Japanese Unexamined Patent Publication No. 2002-300735

Since the electric signal detection device is arranged in the middle of the distribution line, it is desired to reduce the size and weight. Further, in order to arrange the electric signal detection device for each short section of the distribution line, a large number of electric signal detection devices are required. Therefore, a low price is desired for the electric signal detector. On the other hand, a high-voltage instrument transformer is relatively large and relatively expensive because it is necessary to secure insulation and increase the turns ratio. Therefore, an electric signal detector equipped with an instrument transformer is large and expensive, and is inconvenient when a large number of electric signal detectors are arranged on distribution lines. In particular, when detecting the current of each phase of the three-phase distribution wire, three instrument transformers are required, so that the electric signal detection device becomes larger and more expensive.

The present invention has been conceived under the above circumstances, and an object of the present invention is to provide an electric signal detection device which is smaller and lighter than the conventional one and is inexpensive.

In order to solve the above problems, the following technical measures are taken in the present invention.

The electric signal detection device provided by the present invention is an electric signal detection device that is arranged on a three-phase distribution line and detects an electric signal at the arranged position, and is arranged on each distribution line of the three-phase distribution line. It is provided with three current sensors that output a line current detection signal that detects the line current flowing through the arranged distribution line, and each of the current sensors is a coreless type, depending on the magnetic field strength generated around the distribution line. The signal is output as the line current detection signal.

In a preferred embodiment of the present invention, each current sensor includes a magnetic impedance element.

In a preferred embodiment of the present invention, the electric signal detection device further includes a voltage detection unit that outputs three line voltage detection signals that detect the line voltage between the distribution lines, and the voltage detection unit. Is connected in series to each of the three electrodes in contact with the conductor wire of each distribution wire, three voltage dividing resistors connected to each of the electrodes, and one of the voltage dividing resistors at one terminal. Three differentials that output a signal corresponding to the voltage between the three measurement resistors and the two connection points of the voltage dividing resistor and the measurement resistor as an interline voltage detection signal. An amplification circuit is provided, and the other terminals of the three measurement resistors are connected to each other.

In a preferred embodiment of the present invention, a voltage detection unit that outputs three line voltage detection signals that detect the line voltage between the distribution lines is further provided, and the voltage detection unit is the distribution line of the distribution line. The first electrode, the second electrode, and the third electrode, which are in contact with the conductor wire, respectively, the first voltage dividing resistor connected to the first electrode, and one terminal connected in series to the first voltage dividing resistor. A first measurement resistor, a second voltage dividing resistor connected to the second electrode, a second measuring resistor connected in series with the second voltage dividing resistor at one terminal, and the first measuring resistor. A first connection for connecting a third measurement resistor connected between one terminal and one terminal of the second measurement resistor, the first voltage dividing resistor, and the first measurement resistor. A point, a second connection point connecting the second voltage dividing resistor and the second measurement resistor, the other terminal of the first measurement resistor, the other terminal of the second measurement resistor, and the said. It is provided with three differential amplification circuits that output a signal corresponding to the voltage between the two connection points of the third connection point to which the third electrode is connected as a line voltage detection signal.

In a preferred embodiment of the present invention, a power supply unit that supplies electric power by utilizing the voltage between the connection points in the voltage detection unit is further provided.

In a preferred embodiment of the present invention, a zero-phase voltage detection unit that outputs a zero-phase voltage signal that detects the zero-phase voltage of the three-phase distribution wire is further provided, and the zero-phase voltage detection unit uses the three-phase distribution wire. A zero-phase voltage measuring resistor connected to a Y-connected neutral point, a zero-phase voltage dividing resistor connected in series with the zero-phase voltage measuring resistor at one terminal and grounded at the other terminal, and the above. It is equipped with a zero-phase voltage differential amplification circuit that outputs a signal corresponding to the voltage between both terminals of the zero-phase voltage measurement resistor as a zero-phase voltage detection signal.

In a preferred embodiment of the present invention, a zero-phase current detection signal that detects the zero-phase current of the three-phase distribution wire is generated by synthesizing the three line current detection signals detected by each of the current sensors. It also has a compositing section.

In a preferred embodiment of the present invention, each of the current sensors is attached to a conductor wire exposed by removing the insulating coating film of the distribution line via an insulating member.

According to the present invention, each current sensor includes a magnetic impedance element and detects a signal corresponding to the magnetic field strength generated around the distribution line as a line current detection signal. Such a current sensor is smaller, lighter, and less expensive than the instrument transformer used as a conventional current sensor. Therefore, the electric signal detection device according to the present invention is smaller, lighter, and cheaper than the conventional one.

Other features and advantages of the present invention will become more apparent with the detailed description given below with reference to the accompanying drawings.

It is a block diagram which shows the whole structure of the electric signal detection apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the arrangement method of the electric signal detection device shown in FIG. 1 on a three-phase distribution line, (a) is a schematic view which shows the arrangement state on a three-phase distribution line, and (b) is a distribution line and It is a perspective view which shows the connection part of. It is a block diagram which shows the whole structure of the electric signal detection apparatus which concerns on 2nd Embodiment. It is a block diagram which shows the whole structure of the electric signal detection apparatus which concerns on 3rd Embodiment. It is a block diagram which shows the whole structure of the electric signal detection apparatus which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing the overall configuration of the electric signal detection device A1 according to the first embodiment, and shows a state in which the electric signal detection device A1 is arranged on the three-phase distribution electric wire 9. The three phases are composed of a U phase, a V phase, and a W phase. The V phase current is behind the U phase current, and the W phase current is ahead of the U phase current. In the present embodiment, a case where the electric signal detection device A1 detects various electric signals of the U-phase distribution line 91, the V-phase distribution line 92, and the W-phase distribution line 93 of the three-phase distribution line 9 will be described. FIG. 2 is a diagram for explaining a method of arranging the electric signal detection device A1 on the three-phase distribution electric wire 9. FIG. 2A is a schematic view showing a state of arrangement on the three-phase distribution electric wire 9. FIG. 2B is a perspective view showing a connection portion with the distribution line 91.

The electric signal detection device A1 detects various electric signals at the position where the three-phase distribution wire 9 is arranged and transmits them to a master unit (not shown). In the present embodiment, the electric signal detection device A1 detects the line current flowing through the distribution lines 91 to 93 and the line voltage between the distribution lines 91 to 93. The electric signal detection device A1 may detect an electric signal other than the line current and the line voltage.

The electric signal detection device A1 includes a current detection unit 1, a voltage detection unit 2, an A / D conversion unit 3, a communication unit 4, a power supply unit 5, and a main body housing 6.

The current detection unit 1 detects the line current flowing through each of the distribution lines 91 to 93, and outputs a line current detection signal which is a voltage signal corresponding to each detected line current. The current detection unit 1 includes current sensors 1a, 1b, 1c. The current sensor 1a detects the line current flowing through the U-phase distribution line 91. The current sensor 1b detects the line current flowing through the V-phase distribution line 92. The current sensor 1c detects the line current flowing through the W-phase distribution line 93.

The current sensors 1a, 1b, and 1c are coreless current sensors that do not have a magnetic core. As shown in FIG. 2B, the current sensor 1a is attached to the exposed conductor wire 9b by removing the insulating coating film 9a of the distribution line 91 via the insulating member 11. The insulating member 11 is a member for insulating the current sensor 1a from the conductor wire 9b, and is an insulator wound around the conductor wire 9b. The material of the insulating member 11 is not limited, and it is sufficient that the current sensor 1a and the conductor wire 9b can be insulated. Further, the current sensor 1a may be directly attached to the distribution line 91 from above the insulating coating film 9a. In this case, since the distance between the current sensor 1a and the conductor wire 9b becomes large, the detection accuracy deteriorates, but the mounting becomes easy. Similar to the current sensor 1a, the current sensor 1b is attached to the distribution line 92 and the current sensor 1c is attached to the distribution line 93.

In the present embodiment, the current sensors 1a, 1b, 1c include a high-sensitivity micromagnetic sensor (hereinafter, referred to as “MI sensor”) having a magnetic impedance element (Magneto-Impedance element). The MI sensor is a sensor that detects the magnetic field strength by utilizing the magnetic impedance effect of a magnetic impedance element that is a magnetic material having a high magnetic permeability alloy such as an amorphous alloy wire. The current sensor 1a (1b, 1c) responds to the line current by detecting the magnetic field generated around the distribution line 91 (92, 93) by the line current flowing through the distribution line 91 (92, 93) with the MI sensor. The line current detection signal, which is a voltage signal, is output. Since the current sensor 1a (1b, 1c) does not require a magnetic core surrounding the distribution line 91 (92, 93), it is smaller and lighter and lower than the instrument transformer. The price. Further, since the impedance is sensitively changed by the external magnetic field due to the skin effect of the high magnetic permeability alloy magnetic material, the MI sensor can detect the magnetic field strength with high accuracy. Therefore, the current sensors 1a, 1b, and 1c can detect the line current with high accuracy.

The voltage detection unit 2 detects the line voltage of each distribution line 91 to 93, and outputs a line voltage detection signal which is a voltage signal corresponding to each detected line voltage. The voltage detection unit 2 includes electrodes 21a, 21b, 21c, voltage dividing resistors 22a, 22b, 22c, measurement resistors 23a, 23b, 23c, and differential amplifier circuits 25a, 25b, 25c.

The electrodes 21a, 21b, and 21c are connected to the distribution lines 91, 92, and 93, respectively, and are electrodes for extracting voltage. As shown in FIG. 2B, the electrode 21a is connected so as to be in direct contact with the conductor wire 9b exposed by removing the insulating coating film 9a of the distribution line 91. Similar to the electrode 21a, the electrode 21b is attached to the distribution line 92 and the electrode 21c is attached to the distribution line 93.

The voltage dividing resistor 22a and the measuring resistor 23a form a voltage dividing circuit. One terminal of the voltage dividing resistor 22a is connected to the electrode 21a by a connecting wire 26a. The other terminal of the voltage dividing resistor 22a is connected to one terminal of the measuring resistor 23a. That is, the voltage dividing resistor 22a and the measuring resistor 23a are connected in series. The voltage dividing resistor 22b and the measuring resistor 23b form a voltage dividing circuit. One terminal of the voltage dividing resistor 22b is connected to the electrode 21b by a connecting wire 26b. The other terminal of the voltage dividing resistor 22b is connected to one terminal of the measuring resistor 23b. That is, the voltage dividing resistor 22b and the measuring resistor 23b are connected in series. The voltage dividing resistor 22c and the measuring resistor 23c form a voltage dividing circuit. One terminal of the voltage dividing resistor 22c is connected to the electrode 21c by a connecting wire 26c. The other terminal of the voltage dividing resistor 22c is connected to one terminal of the measuring resistor 23c. That is, the voltage dividing resistor 22c and the measuring resistor 23c are connected in series. The other terminals of the measuring resistors 23a, 23b, 23c are connected to each other at the connection point 24. That is, the connection lines 26a, 26b, and 26c branched from the distribution lines 91, 92, and 93 of the three-phase distribution line 9 are connected by a Y connection with the connection point 24 as the neutral point, respectively, via a voltage dividing circuit. There is.

Resistors with the same resistance value are used as the voltage dividing resistors 22a, 22b, and 22c. The resistance value is, for example, about 10 MΩ to 10 GΩ, and in this embodiment, it is about 10 MΩ. Further, the measuring resistors 23a, 23b and 23c use resistors having the same resistance value. The resistance value is sufficiently smaller than the resistance values of the voltage dividing resistors 22a, 22b, and 22c, for example, about 10 kΩ to 10 MΩ, and in this embodiment, about 10 kΩ. The resistance values of the voltage dividing resistors 22a, 22b and 22c and the resistance values of the measuring resistors 23a, 23b and 23c are not limited.

The voltage at the connection point 27a between the other terminal of the voltage dividing resistor 22a and one terminal of the measuring resistor 23a is the voltage of the distribution line 91 with respect to the neutral point, the resistance value of the voltage dividing resistor 22a and the measuring resistor 23a. The voltage is divided by the ratio with the resistance value. Similarly, the voltage at the connection point 27b between the other terminal of the voltage dividing resistor 22b and one terminal of the measuring resistor 23b is the voltage of the distribution wire 92 with respect to the neutral point, the resistance value of the voltage dividing resistor 22b and the measurement. The voltage is divided by the ratio with the resistance value of the resistor 23b. Further, the voltage at the connection point 27c between the other terminal of the voltage dividing resistor 22c and one terminal of the measuring resistor 23c is the voltage of the distribution wire 93 with respect to the neutral point, the resistance value of the voltage dividing resistor 22c and the measuring resistance. The voltage is divided by the ratio with the resistance value of 23c.

The differential amplifier circuit 25a detects the line voltage between the distribution line 91 and the distribution line 92. The non-inverting input terminal of the differential amplifier circuit 25a is connected to the connection point 27a, and the voltage dividing voltage of the distribution line 91 is input. The inverting input terminal of the differential amplifier circuit 25a is connected to the connection point 27b, and the voltage dividing voltage of the distribution line 92 is input. The differential amplification circuit 25a detects a voltage signal corresponding to the difference between the divided voltage of the distribution line 91 and the divided voltage of the distribution line 92, and detects the line voltage of the distribution line 91 with respect to the distribution line 92. Output as a signal. Similarly, the differential amplifier circuit 25b detects the line voltage between the distribution line 92 and the distribution line 93. The non-inverting input terminal of the differential amplifier circuit 25b is connected to the connection point 27b, and the voltage dividing voltage of the distribution line 92 is input. The inverting input terminal of the differential amplifier circuit 25b is connected to the connection point 27c, and the voltage dividing voltage of the distribution line 93 is input. The differential amplification circuit 25b detects a voltage signal corresponding to the difference between the divided voltage of the distribution line 92 and the divided voltage of the distribution line 93, and detects the line voltage of the distribution line 92 with respect to the distribution line 93. Output as a signal. Further, the differential amplifier circuit 25c detects the line voltage between the distribution line 93 and the distribution line 91. The non-inverting input terminal of the differential amplifier circuit 25c is connected to the connection point 27c, and the voltage dividing voltage of the distribution line 93 is input. The inverting input terminal of the differential amplifier circuit 25c is connected to the connection point 27a, and the voltage dividing voltage of the distribution line 91 is input. The differential amplification circuit 25c detects a voltage signal corresponding to the difference between the divided voltage of the distribution line 93 and the divided voltage of the distribution line 91, and detects the line voltage of the distribution line 93 with respect to the distribution line 91. Output as a signal. The specific circuit configuration of the differential amplifier circuits 25a, 25b, and 25c is not limited.

The A / D conversion unit 3 converts an analog signal into a digital signal. The A / D conversion unit 3 inputs each line current detection signal detected by the current detection unit 1 and each line voltage detection signal detected by the voltage detection unit 2, converts them into digital signals, and outputs the signals to the communication unit 4. .. An analog filter or an amplifier circuit may be arranged in front of the A / D conversion unit 3. Further, a digital filter may be arranged after the A / D conversion unit 3.

The communication unit 4 transmits each digitized line current detection signal and each line voltage detection signal input from the A / D conversion unit 3 to a master unit (not shown) by wireless communication. The communication unit 4 may constantly transmit various signals, or may transmit various signals only when an abnormality is detected. Further, when high sampling measurement, large-capacity data transmission, or high-frequency data transmission is required, the communication unit 4 may perform sleep / wake-up control that is activated only during communication in order to suppress power consumption. Good. The communication method in the communication unit 4 is not limited, and communication may be based on a short-range wireless communication standard such as Bluetooth (registered trademark), or long-distance wireless communication provided by a telecommunications carrier may be used. You may. The communication unit 4 may perform communication by wire communication.

The power supply unit 5 generates the electric power required by the electric signal detection device A1. The power supply unit 5 is connected to the connection points 27a, 27b, 27c of the voltage detection unit 2, and uses the divided voltage. The power supply unit 5 converts the AC power input from the connection points 27a, 27b, 27c into DC power having a predetermined voltage and supplies the AC power to the communication unit 4 and the like. The power supply unit 5 includes a rectifier circuit 51, a capacitor 52, and a DC / DC conversion circuit 53. The rectifier circuit 51 converts the AC power input from the connection points 27a, 27b, 27c into DC power and outputs it. The rectifier circuit 51 is, for example, a diode three-phase full bridge circuit and a full-wave rectifier circuit. The capacitor 52 is a smoothing capacitor that smoothes the DC voltage output from the rectifier circuit 51. The DC / DC conversion circuit 53 transforms the DC voltage output from the capacitor 52 into a predetermined voltage and outputs the DC voltage. The internal configuration of the power supply unit 5 is not limited to the above.

The main body housing 6 houses the A / D conversion unit 3, the communication unit 4, and the power supply unit 5 in addition to the electrodes 21a, 21b, and 21c of the voltage detection unit 2. The main body housing 6 and the current sensor 1a (1b, 1c) are connected by a connecting line 12a (12b, 12c), and the main body housing 6 and the electrodes 21a (21b, 21c) are connected by a connecting line 26a (26b, 26c). It is connected. As shown in FIG. 2A, the main body housing 6 is attached to any of the distribution lines 91 to 93. In FIG. 2A, the main body housing 6 is attached to the distribution line 93 arranged at the lowest position among the distribution lines 91 to 93 arranged in the vertical direction. The distribution line on which the main body housing 6 is arranged is not limited.

Next, a method of arranging the electric signal detection device A1 will be described.

In the present embodiment, the current sensors 1a, 1b, 1c and the electrodes 21a, 21b, 21c are directly arranged on the live line by the uninterruptible power supply method. First, the insulating coating film 9a of the distribution line 91 is removed by using the electric wire coating stripping tool used in the uninterruptible power supply method. Next, the insulating member 11 and the electrode 21a are arranged on the exposed conductor wire 9b, and the current sensor 1a is attached to the insulating member 11 (see FIG. 2B). Then, the insulating coating cover 81 is attached to the removed portion of the insulating coating film 9a of the distribution line 91 (see the arrow in FIG. 2B). In the same manner as in the case of the distribution line 91, the electrode 21b and the current sensor 1b are arranged on the distribution line 92 to attach the insulating coating cover 82, and the electrodes 21c and the current sensor 1c are arranged on the distribution line 93 to provide the insulating coating cover 83. Install (see FIG. 2 (a)).

Next, the main body housing 6 is attached to any of the distribution lines 91 to 93. In FIG. 2A, the main body housing 6 is attached to the distribution line 93. The method of arranging the main body housing 6 is not limited. The main body housing 6 may be arranged on any one of the distribution lines 91 to 93, or may be arranged so as to straddle between any two of the distribution lines 91 to 93. Further, it may be arranged so as to straddle the distribution lines 91 to 93. The main body housing 6 is appropriately arranged according to the arrangement direction of the distribution lines 91 to 93, the arrangement method of the other electric signal detection device A1 arranged on the same distribution lines 91 to 93, and the like.

Next, the operation and effect of the electric signal detection device A1 according to the present embodiment will be described.

According to this embodiment, the current sensor 1a (1b, 1c) includes a magnetic impedance element and detects a signal corresponding to the magnetic field strength generated around the distribution line 91 (92, 93) as a line current detection signal. The current sensors 1a, 1b, and 1c are smaller, lighter, and less expensive than the instrument transformers used as conventional current sensors. Therefore, the electric signal detection device A1 is smaller, lighter, and cheaper than the conventional electric signal detection device.

Further, according to the present embodiment, the voltage detection unit 2 divides the voltage of each of the distribution wires 91 to 93, which is divided by three voltage dividing circuits connected by a Y connection with the connection point 24 as the neutral point. A voltage signal corresponding to the voltage difference is detected as a line voltage detection signal. The voltage detection unit 2 is smaller, lighter, and less expensive than the instrument transformer used as a conventional voltage sensor. This contributes to the reduction in size and weight and the price reduction of the electric signal detection device A1.

Further, according to the present embodiment, the electric signal detection device A1 includes a power supply unit 5 that supplies electric power by using the voltage divided by the voltage dividing circuit of the voltage detecting unit 2. Therefore, the electric signal detection device A1 is easily and stably supplied with electric power. Further, the power supply unit 5 can be made smaller and lighter than the case where the voltage to ground of the distribution lines 91 to 93 is used, or when a solar cell or the like is provided, and can be configured at a low price. This contributes to the reduction in size and weight and the price reduction of the electric signal detection device A1.

Further, according to the present embodiment, the current sensors 1a, 1b, 1c and the electrodes 21a, 21b, 21c can be directly arranged on the live line by the uninterruptible power supply method. Therefore, the electric signal detection device A1 can be easily arranged later on the already used and energized distribution line. As a result, on-site measurement on distribution lines can be realized at an early stage.

Further, according to the present embodiment, the current sensor 1a (1b, 1c) is attached to the exposed conductor wire 9b by removing the insulating coating film 9a of the distribution line 91 (92, 93) via the insulating member 11. Has been done. Since the current sensor 1a (1b, 1c) can reduce the distance from the conductor wire 9b as compared with the case where the current sensor 1a (1b, 1c) is directly attached to the distribution line 91 (92, 93) from above the insulating coating film 9a, the detection accuracy Can be improved.

In the present embodiment, the case where the current sensors 1a, 1b, and 1c are provided with a high-sensitivity micromagnetic sensor (MI sensor) having a magnetic impedance element has been described, but the present invention is not limited to this. The current sensors 1a, 1b, 1c include, for example, a magnetoresistive sensor (MR element), an anisotropic magnetoresistive element (AMR element), a giant magnetoresistive element (GMR element), a tunnel magnetoresistive element (TMR element), and a hole. A magnetic sensor having an element, a superconducting quantum interference element (SQUID element), or the like may be provided. The current sensors 1a, 1b, and 1c may be coreless current sensors that do not have a magnetic core and may be attached to each distribution line as shown in FIG. 2 (b).

Further, in the present embodiment, the case where the line current detection signal and the line voltage detection signal detected by the electric signal detection device A1 are transmitted has been described, but the present invention is not limited to this. The electric signal detection device A1 may calculate the power from the detected line current and the line voltage, and transmit the power detection signal. In this case, a wattmeter IC for a smart meter incorporating an A / D converter 3, a digital filter, and a DSP (Digital Signal Processor) that calculates power may be used.

Further, in the present embodiment, the case where the electric signal detection device A1 includes the power supply unit 5 that supplies power by using the voltage divided by the voltage divider circuit of the voltage detection unit 2 has been described. Not limited. The electric signal detection device A1 may include a power supply unit having one or more types of energy harvesting elements such as a solar cell and a vibration power generation element instead of the power supply unit 5. Further, both the power supply unit and the power supply unit 5 may be provided.

Further, in the present embodiment, the case where the power supply unit 5 is connected to the connection points 27a, 27b, 27c of the voltage detection unit 2 has been described, but the present invention is not limited to this. The electric signal detection device A1 may further have the same configuration as the three voltage dividing circuits of the voltage detecting unit 2, and the power supply unit 5 may use the voltage divided by the added voltage dividing circuit. That is, the electric signal detection device A1 may be provided with separate voltage dividing circuits for power supply and line voltage detection. In this case, it is possible to prevent the line voltage detection signal from being distorted due to the influence of the power supply unit 5.

[Second Embodiment]
FIG. 3 is a diagram for explaining the electric signal detection device A2 according to the second embodiment, and is a block diagram showing the overall configuration of the electric signal detection device A2. In the figure, the same or similar elements as those of the electric signal detection device A1 (see FIG. 1) are designated by the same reference numerals, and redundant description will be omitted. In FIG. 3, the power supply unit 5 is shown in a simplified manner.

The electric signal detection device A2 according to the present embodiment is different from the electric signal detection device A1 in that the voltage detection unit 2 detects the phase voltage of each of the distribution lines 91 to 93.

The voltage detection unit 2 according to the present embodiment detects the phase voltage of each distribution line 91 to 93 and outputs a phase voltage detection signal which is a voltage signal corresponding to each detected phase voltage. The configuration of the three voltage dividing circuits constituting the voltage detection unit 2 is the same as in the case of the first embodiment. The non-inverting input terminal of the differential amplifier circuit 25a is connected to the connection point 27a, and the inverting input terminal of the differential amplifier circuit 25a is connected to the connection point 24 (neutral point). The differential amplification circuit 25a outputs a voltage signal corresponding to the difference between the voltage at the connection point 27a and the voltage at the connection point 24 as a phase voltage detection signal that detects the phase voltage of the distribution line 91 with respect to the neutral point. Similarly, the non-inverting input terminal of the differential amplifier circuit 25b is connected to the connection point 27b, and the inverting input terminal of the differential amplifier circuit 25b is connected to the connection point 24. The differential amplification circuit 25b outputs a voltage signal corresponding to the difference between the voltage at the connection point 27b and the voltage at the connection point 24 as a phase voltage detection signal that detects the phase voltage of the distribution line 92 with respect to the neutral point. Further, the non-inverting input terminal of the differential amplifier circuit 25c is connected to the connection point 27c, and the inverting input terminal of the differential amplifier circuit 25c is connected to the connection point 24 (neutral point). The differential amplification circuit 25c outputs a voltage signal corresponding to the difference between the voltage at the connection point 27c and the voltage at the connection point 24 as a phase voltage detection signal that detects the phase voltage of the distribution line 93 with respect to the neutral point.

In this embodiment, the phase voltage detection signal is a signal that accurately detects the phase voltage of each distribution line 91 to 93 when the three voltage dividing circuits of the voltage detection unit 2 are a three-phase balanced load. It is a case that can be regarded. Even when the three voltage dividing circuits of the voltage detection unit 2 cannot be regarded as a three-phase balanced load, each phase voltage detection signal can be used as a signal for detecting the balanced state of the three-phase distribution wire 9.

Also in this embodiment, the same effect as that of the first embodiment can be obtained.

[Third Embodiment]
FIG. 4 is a diagram for explaining the electric signal detection device A3 according to the third embodiment, and is a block diagram showing the overall configuration of the electric signal detection device A3. In the figure, the same or similar elements as those of the electric signal detection device A1 (see FIG. 1) are designated by the same reference numerals, and redundant description will be omitted. In FIG. 4, the power supply unit 5 is shown in a simplified manner.

The electric signal detection device A3 according to the present embodiment is an electric signal detection device A1 in that the connection lines 26a, 26b, 26c branched from the distribution lines 91, 92, 93 of the three-phase distribution line 9 are connected by V connection. Different from.

The voltage detection unit 2 according to the present embodiment does not include a voltage dividing resistor 22b. The voltage dividing resistor 22a and the measuring resistor 23a, and the voltage dividing resistor 22c and the measuring resistor 23c form a voltage dividing circuit. The measurement resistor 23b is connected between one terminal of the measurement resistor 23a and one terminal of the measurement resistor 23c. The other terminal of the measuring resistor 23a, the other terminal of the measuring resistor 23c, and the electrode 21b are connected to each other at the connection point 28. That is, the connection lines 26a, 26b, and 26c branched from the distribution lines 91, 92, and 93 of the three-phase distribution line 9 are connected by V connection. The voltage at the connection point 27a is a voltage obtained by dividing the voltage of the distribution line 91 with respect to the distribution line 92 by the ratio of the resistance value of the voltage dividing resistor 22a and the resistance value of the measuring resistor 23a. Similarly, the voltage at the connection point 27c is a voltage obtained by dividing the voltage of the distribution line 93 with respect to the distribution line 92 by the ratio of the resistance value of the voltage dividing resistor 22c and the resistance value of the measuring resistor 23c. As the voltage dividing resistors 22a and 22c, resistors having the same resistance value are used. Further, the measuring resistors 23a, 23b and 23c use resistors having the same resistance value.

The electrodes 21a, 21b, and 21c according to the present embodiment correspond to the "first electrode", "third electrode", and "second electrode" of the present invention, respectively. Further, the voltage dividing resistor 22a and the voltage dividing resistor 22c correspond to the "first voltage dividing resistor" and the "second voltage dividing resistor" of the present invention, respectively. Further, the measurement resistor 23a, the measurement resistor 23b, and the measurement resistor 23c correspond to the "first measurement resistor", "third measurement resistor", and "second measurement resistor" of the present invention, respectively. To do. Further, the connection points 27a, 27c, and 28 correspond to the "first connection point", the "second connection point", and the "third connection point" of the present invention, respectively.

The differential amplifier circuit 25a detects the line voltage between the distribution line 91 and the distribution line 92. The non-inverting input terminal of the differential amplifier circuit 25a is connected to the connection point 27a, and the inverting input terminal of the differential amplifier circuit 25a is connected to the connection point 28. The differential amplifier circuit 25a outputs a voltage signal corresponding to the difference between the voltage at the connection point 27a and the voltage at the connection point 28 as a line voltage detection signal that detects the line voltage of the distribution line 91 with respect to the distribution line 92. To do. Similarly, the differential amplifier circuit 25b detects the line voltage between the distribution line 92 and the distribution line 93. The non-inverting input terminal of the differential amplifier circuit 25b is connected to the connection point 28, and the inverting input terminal of the differential amplifier circuit 25b is connected to the connection point 27c. The differential amplifier circuit 25b outputs a voltage signal corresponding to the difference between the voltage at the connection point 28 and the voltage at the connection point 27c as a line voltage detection signal that detects the line voltage of the distribution line 92 with respect to the distribution line 93. To do. Further, the differential amplifier circuit 25c detects the line voltage between the distribution line 93 and the distribution line 91. The non-inverting input terminal of the differential amplifier circuit 25c is connected to the connection point 27c, and the inverting input terminal of the differential amplifier circuit 25c is connected to the connection point 27a. The differential amplification circuit 25c outputs a voltage signal corresponding to the difference between the voltage at the connection point 27c and the voltage at the connection point 27a as a line voltage detection signal that detects the line voltage of the distribution line 93 with respect to the distribution line 91. To do.

The power supply unit 5 is connected to the connection points 27a, 28, 27c of the voltage detection unit 2, and uses the divided voltage. The power supply unit 5 converts the AC power input from the connection points 27a, 28, 27c into DC power having a predetermined voltage and supplies the AC power to the communication unit 4 and the like.

According to the present embodiment, in the voltage detection unit 2, the connection lines 26a, 26b, 26c are connected by a V connection, and the measurement resistors 23a, 23c of the voltage dividing circuit arranged on the connection lines 26a, 26c and the measurement resistors 23a, 23c. A voltage signal corresponding to the voltage between each terminal of the measurement resistor 23b connected between the 23a and the measurement resistor 23c is detected as a line voltage detection signal. The voltage detection unit 2 is smaller, lighter, and less expensive than the instrument transformer used as a conventional voltage sensor. Therefore, the same effect as that of the first embodiment can be obtained in this embodiment as well.

[Fourth Embodiment]
FIG. 5 is a diagram for explaining the electric signal detection device A4 according to the fourth embodiment, and is a block diagram showing the overall configuration of the electric signal detection device A4. In the figure, the same or similar elements as those of the electric signal detection device A1 (see FIG. 1) are designated by the same reference numerals, and redundant description will be omitted. In FIG. 5, the power supply unit 5 is shown in a simplified manner.

The electric signal detection device A4 according to the present embodiment is different from the electric signal detection device A1 in that it detects the zero-phase voltage and the zero-phase current of the three-phase distribution wire 9.

The voltage detection unit 2 according to the present embodiment detects the zero-phase voltage of the three-phase distribution line 9 in addition to the line voltage of each distribution line 91 to 93. The voltage detection unit 2 detects the zero-phase voltage of the three-phase distribution wire 9, and outputs a zero-phase voltage detection signal which is a voltage signal corresponding to the detected zero-phase voltage. The voltage detection unit 2 further includes a voltage dividing resistor 22d, a measuring resistor 23d, and a differential amplifier circuit 25d. The voltage dividing resistor 22d and the measuring resistor 23d form a voltage dividing circuit. One terminal of the measuring resistor 23d is connected to the connection point 24 (neutral point). The other terminal of the measuring resistor 23d is connected to one terminal of the voltage dividing resistor 22d. The other terminal of the voltage dividing resistor 22d is grounded. That is, the voltage dividing resistor 22d and the measuring resistor 23d are connected in series between the neutral point and the ground. The voltage at the connection point 27d between the other terminal of the measuring resistor 23d and the one terminal of the voltage dividing resistor 22d is the voltage to ground at the neutral point, the resistance value of the voltage dividing resistor 22d and the resistance value of the measuring resistor 23d. The voltage is divided according to the ratio of. In the present embodiment, the voltage dividing resistor 22d is the voltage dividing resistor 22a, 22b so that the voltage dividing ratio of the voltage dividing resistor 22d and the measuring resistor 23d is the same as the voltage dividing ratio of the voltage dividing resistor 22a and the measuring resistor 23a. , 22c and the same resistance value resistance are used, and the measurement resistance 23d uses the same resistance value as the measurement resistances 23a, 23b and 23c.

The zero-phase voltage detector (ZPD) conventionally arranged in the distribution system is grounded via a capacitor. The ground impedance of each phase due to this grounding is about 10 MΩ. This is a sufficiently large value as compared with the ground impedance of each phase of about 10 kΩ by the ground transformer provided for ground fault detection. In the present embodiment, the resistance value of the voltage dividing resistor 22d of the voltage detection unit 2 is set to 10 MΩ or more to prevent the impedance to ground of each phase from becoming small, and the influence of the electric signal detection device A4 on the distribution system is as much as possible. I'm holding back.

The differential amplifier circuit 25d detects the zero-phase voltage of the three-phase distribution wire 9. The non-inverting input terminal of the differential amplifier circuit 25d is connected to the connection point 24, and the inverting input terminal of the differential amplifier circuit 25d is connected to the connection point 27d. The differential amplifier circuit 25d outputs a voltage signal corresponding to the difference between the voltage at the connection point 24 and the voltage at the connection point 27d as a zero-phase voltage detection signal that detects the zero-phase voltage of the three-phase distribution wire 9. The voltage dividing ratio of the voltage dividing resistor 22d and the measuring resistor 23d is the same as the voltage dividing ratio of the voltage dividing resistor 22a and the measuring resistor 23a. Therefore, the zero-phase voltage detection signal becomes a voltage signal divided by the same voltage division ratio as in the case of the line voltage signal.

In the present embodiment, the voltage detection unit 2 corresponds to the "zero-phase voltage detection unit" of the present invention. Further, the voltage dividing resistor 22d, the measuring resistor 23d, and the differential amplifier circuit 25d are the "zero-phase voltage dividing resistor", the "zero-phase voltage measuring resistor", and the "zero-phase voltage differential" of the present invention, respectively. Corresponds to "amplifier circuit".

Further, the electric signal detection device A4 further includes a synthesis unit 13. The synthesis unit 13 detects the zero-phase current of the three-phase distribution wire 9, and outputs a zero-phase current detection signal which is a voltage signal corresponding to the detected zero-phase current. The synthesis unit 13 receives line current detection signals from the current sensors 1a, 1b, and 1c, respectively, synthesizes the three input line current detection signals, and outputs them as zero-phase current detection signals.

The A / D conversion unit 3 also converts the zero-phase current detection signal synthesized by the synthesis unit 13 and the zero-phase voltage detection signal detected by the voltage detection unit 2 into digital signals and outputs them to the communication unit 4. The communication unit 4 also transmits the digitized zero-phase current detection signal and zero-phase voltage detection signal input from the A / D conversion unit 3.

According to this embodiment, the electric signal detection device A4 generates a zero-phase current detection signal by detecting each line current detection signal by the current sensors 1a, 1b, 1c and synthesizing each line current detection signal by the synthesis unit 13. To do. The current sensors 1a, 1b, and 1c are smaller, lighter, and less expensive than the zero-phase current transformer (ZCT) used as a conventional zero-phase current sensor. Therefore, the electric signal detection device A4 is smaller, lighter, and cheaper than the conventional electric signal detection device.

Further, according to the present embodiment, the voltage detection unit 2 corresponds to the zero-phase voltage of the three-phase distribution wire 9 divided by the voltage dividing circuit connected between the connection point 24 (neutral point) and the ground. The voltage signal is detected as a zero-phase voltage detection signal. The voltage detection unit 2 is smaller, lighter, and less expensive than the zero-phase voltage detection device (ZPD) used as a conventional zero-phase voltage sensor. This contributes to the reduction in size and weight and the price reduction of the electric signal detection device A4.

In the present embodiment, the case where the voltage detection unit 2 detects the line voltage of each distribution line 91 to 93 and the zero-phase voltage of the three-phase distribution line 9 has been described, but the present invention is not limited to this. The voltage detection unit 2 may detect only the zero-phase voltage of the three-phase distribution line 9 without detecting the line voltage of each distribution line 91 to 93. In this case, the voltage detection unit 2 can omit the voltage dividing resistors 22a, 22b, 22c, the measuring resistors 23a, 23b, 23c, and the differential amplifier circuits 25a, 25b, 25c.

In the first to fourth embodiments, the case where various signals detected by the electric signal detection devices A1 to A4 are transmitted to the master unit has been described, but the present invention is not limited to this. The electric signal detection devices A1 to A4 may directly transmit the detected various signals to a power distribution automation device such as a corresponding switch slave station or a control device of an automatic voltage regulator (SVR). Further, various power distribution automation devices may include electric signal detection devices A1 to A4. In this case, each distribution automation machine corresponds to the "electric signal detection device" of the present invention.

The electric signal detection device according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the electric signal detection device according to the present invention can be freely redesigned.

A1, A2, A3, A4: Electric signal detector, 1a, 1b, 1c: Current sensor 2: Voltage detector, 21a, 21b, 21c: Electrode, 22a, 22b, 22c, 22d: Pressure dividing resistor, 23a, 23b, 23c, 23d: Measurement resistor, 25a, 25b, 25c, 25d: Differential amplifier circuit, 5: Power supply unit, 13: Synthesis unit, 9: Three-phase distribution wire, 91,92,93: Distribution wire, 9a: Insulation coating film, 9b: Conductor wire, 11: Insulation member

Claims (7)

It is an electric signal detection device that is placed on a three-phase distribution wire and detects an electric signal at the placed position.
It is provided with three current sensors arranged on each distribution line of the three-phase distribution line and output a line current detection signal for detecting the line current flowing through the arranged distribution lines.
Each of the current sensors
It is a coreless type
A signal corresponding to the magnetic field strength generated around the distribution line is output as the line current detection signal.
An electric signal detection device characterized by the fact that. Each of the current sensors includes a magnetic impedance element.
The electric signal detection device according to claim 1. It is further equipped with a voltage detection unit that outputs three line voltage detection signals that detect the line voltage between each distribution line.
The voltage detection unit
Three electrodes that come into contact with the conductor wires of each distribution line,
Three voltage dividing resistors connected to each of the electrodes,
Three measuring resistors connected in series to each voltage dividing resistor at one terminal, and
Three differential amplifier circuits that output a signal corresponding to the voltage between two connection points of the connection point between the voltage dividing resistor and the measurement resistor as a line voltage detection signal, and
With
The other terminals of the three measuring resistors are connected to each other.
The electric signal detection device according to claim 1 or 2. It is further equipped with a voltage detection unit that outputs three line voltage detection signals that detect the line voltage between each distribution line.
The voltage detection unit
The first electrode, the second electrode, and the third electrode that come into contact with the conductor wire of each distribution line, respectively,
The first voltage dividing resistor connected to the first electrode and
A first measurement resistor connected in series with the first voltage dividing resistor at one terminal,
The second voltage dividing resistor connected to the second electrode and
A second measurement resistor connected in series with the second voltage dividing resistor at one terminal,
A third measurement resistor connected between one terminal of the first measurement resistor and one terminal of the second measurement resistor.
A first connection point for connecting the first voltage dividing resistor and the first measurement resistor, a second connection point for connecting the second voltage dividing resistor and the second measurement resistor, and the first measurement. The line voltage is a signal corresponding to the voltage between two connection points of the other terminal of the resistance for measurement, the other terminal of the resistance for second measurement, and the third connection point for connecting the third electrode. Three differential amplifier circuits that output as detection signals and
Is equipped with
The electric signal detection device according to claim 1 or 2. It further includes a power supply unit that supplies power by using the voltage between the connection points in the voltage detection unit.
The electric signal detection device according to claim 3 or 4. A zero-phase voltage detector that outputs a zero-phase voltage signal that detects the zero-phase voltage of the three-phase distribution wire is further provided.
The zero-phase voltage detector
A zero-phase voltage measurement resistor connected to the neutral point where the three-phase distribution wire is Y-connected,
A zero-phase voltage dividing resistor connected in series to the zero-phase voltage measuring resistor at one terminal and grounded at the other terminal.
A zero-phase voltage differential amplifier circuit that outputs a signal corresponding to the voltage between both terminals of the zero-phase voltage measurement resistor as a zero-phase voltage detection signal.
Is equipped with
The electric signal detection device according to any one of claims 1 to 3. Each of the current sensors is attached to a conductor wire exposed by removing the insulating coating film of the distribution line via an insulating member.
The electric signal detection device according to any one of claims 1 to 6.

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