TWI493197B - Power meter - Google Patents

Description

Electric measuring device

The present invention relates to a power measuring device.

【Background technique】

In an office building, a retail store, or a university, the power received from the power distribution system of the power company and received by the power receiving device is shunted to a plurality of shunt circuits by a power distribution board or a distribution board to be supplied to each The load connected by the shunt circuit.

In the past, the mains current was measured at the point of introduction of the power distribution system, and the total power consumption was measured based on the main current. However, in recent years, the awareness of power saving and power saving has increased, and it is expected to measure the power consumption in each shunt circuit. Measures to save power and save electricity. For example, the multi-circuit power meter disclosed in the document 1 (Japanese Laid-Open Patent Publication No. 2005-55404) can measure the amount of power consumption at a plurality of points, or can increase the measurement point by adding an additional unit.

The multi-circuit power meter disclosed in the above-mentioned document 1 is provided on the switchboard and the distribution board, and in order to confirm the measurement result of the power consumption amount, it has to go to the installation place of the distribution board or the distribution board, and the procedure is cumbersome and time consuming.

Therefore, it is considered that the measurement result of the power consumption amount is periodically transmitted from the multi-circuit power meter to an external device (for example, a management server) that is easily accessible to the power demander or the facility manager, and the measurement result is displayed. For external devices.

In this case, the connection terminal for connecting the communication line is formed on the surface of the multi-circuit power meter The communication line is connected between the communication unit having the multi-circuit power meter and the external device.

Therefore, when any work is performed in the disc (for example, a work of connecting a communication line to a connection terminal, etc.), the operator's body may touch the connection terminal. Further, when the communication unit is not grounded, if the static electricity carried in the worker's body is discharged to the connection terminal, a surge voltage and a surge current due to static electricity may be applied to the circuit components constituting the communication unit.

Therefore, the circuit components constituting the communication portion must use high-voltage components, resulting in an increase in cost.

In view of the above problems, it is an object of the invention to provide a power measuring device capable of reducing a surge voltage or a surge current applied to a circuit component constituting a communication unit.

A power measuring device according to a first aspect of the present invention includes: a power measuring unit that measures power; a communication terminal that is used to connect a communication line; and a communication unit that outputs the power measuring unit to be connected to the communication terminal The power value measured by the communication line; the first ground terminal is connected to the ground line (the ground line is used to ground the power measuring device); the second ground terminal is connected to the shield line (the shield line makes the communication line And an electromagnetic shielding mechanism; and a surge protection mechanism connected between the first ground terminal and the second ground terminal.

In the electric energy measuring device according to the second aspect of the present invention, the surge protection mechanism in the first aspect is configured to electrically connect the first ground terminal and the second ground terminal when a surge occurs. The way it is composed.

In the electric power measuring device according to the third aspect of the present invention, the surge protection mechanism in the first or second aspect is a surge protection element.

In the electric power measuring device according to the fourth aspect of the present invention, the surge protection member in the third aspect is an air gap discharger (Gap Arrester).

In the power measuring device according to the fifth aspect of the present invention, the first or second aspect further includes a circuit board on which the first ground terminal and the second ground terminal are mounted. The surge protection mechanism includes a first conductive layer connected to the first ground terminal and a second conductive layer connected to the second ground terminal. The first conductive layer and the second conductive layer are formed on the circuit board so as to face each other with a predetermined interval therebetween. The predetermined interval is set such that the first conductive layer and the second conductive layer are electrically connected when a surge occurs.

In the power measuring device according to the sixth aspect of the present invention, the circuit board of the fifth aspect further includes the first circuit board and the second circuit board. The first ground terminal is mounted on the first circuit board. The second ground terminal is attached to the second circuit board. The first conductive layer and the second conductive layer are formed on one of the first circuit substrate and the second circuit substrate.

In the electric energy measuring device according to the seventh aspect of the present invention, the first or second aspect further includes the first circuit board having the first surface and the second circuit surface having the first surface facing the first surface. Circuit board. The first ground terminal is mounted on the first circuit board. The second ground terminal is attached to the second circuit board. The surge protection mechanism has a first protrusion and a second protrusion. The first protrusion is disposed on the first surface of the first circuit board, and is electrically connected to the first ground terminal. The second protrusion is disposed on the second surface of the second circuit board so as to face the first protrusion at a predetermined interval, and is electrically connected to the second ground terminal. The predetermined interval is set such that the first protrusion and the second protrusion are electrically connected when a surge occurs.

In the electric energy measuring device according to the eighth aspect of the present invention, the seventh aspect further includes a first casing accommodating the first circuit board and a second casing accommodating the second circuit board. The first case has a first opening that exposes the first surface of the first circuit board. The second case has a second opening that exposes the second surface of the second circuit board. The second casing is attached to the first casing such that the second opening and the first opening face each other.

In a power measuring device according to a ninth aspect of the present invention, any one of the first to eighth aspects further includes: a power supply terminal for connecting to a power supply line from an external power supply; and a power supply circuit unit, The power received from the external power source is supplied to the power measuring unit and the communication unit through the power line connected to the power terminal. The first connection terminal is connected to the power supply circuit unit.

In the electric energy measuring device according to the tenth aspect of the present invention, the first connection terminal in any one of the first to ninth aspects is connected to the electric power measuring unit.

1A‧‧‧ body unit

1B‧‧‧Additional unit

10‧‧‧Power Measurement Department

11‧‧‧ Current Measurement Department

11a‧‧‧ current comparator

12‧‧‧Voltage measurement department

13‧‧‧Power Calculation Department

14‧‧‧I/F Department for Memory Cards

15‧‧‧Communication Department

16‧‧‧Display Department

17‧‧‧Power Circuit Division

18‧‧‧air gap arrester

20, 22‧‧‧ wiring pattern

23‧‧‧1st protrusion

24‧‧‧2nd protrusion

25‧‧‧ pattern gap

50‧‧‧ body

51‧‧‧ Body Department

51d, 51c‧‧‧ rectangular holes

52‧‧‧ 盖部

52a, 52b, 52c, 53c, 53d, 54a, 54b, 55a, 55b, 55c, 62a, 65a‧‧‧ through holes

53‧‧‧Protruding

54, 55‧‧ Section

61e‧‧‧flexible film

61‧‧‧ Body Department

61f‧‧‧ claws

61g‧‧‧ditch

62‧‧‧ 盖部

62b‧‧‧through hole

63‧‧‧Protruding

66‧‧‧latch

100‧‧‧Management device

181, 182‧‧‧ terminals

251‧‧‧1st conductive layer

252‧‧‧2nd conductive layer

B1‧‧‧1st circuit substrate

B2‧‧‧2nd circuit substrate

CB1‧‧‧Power cable

CB2‧‧‧ cable

CB3‧‧‧ Grounding wire

CB4‧‧‧ output line

CB5‧‧‧ communication line

CB6‧‧‧Shielded wire

CN11, CN21‧‧‧ connector

MC1‧‧‧ memory card

SL1‧‧‧ card slot

T11, T12, T13, T15, T16, T17, T21‧‧‧ connection terminals

Fig. 1 is a block diagram showing a state in which a communication line is not connected in a main body unit of an electric power measuring device according to an embodiment of the present invention.

Fig. 2 is a block diagram showing a state in which a communication line is connected to a main body unit of the above-described electric power measuring device.

Fig. 3 is a schematic cross-sectional view showing a main body unit of the electric power measuring device.

Fig. 4 (a) is a front view of the electric power measuring device, (b) is a plan view of the electric power measuring device, and (c) is a bottom view of the electric power measuring device.

Fig. 5 is a left side view of the above power measuring device.

Fig. 6 is a right side view of the above power measuring device.

Fig. 7 is an external perspective view of the above electric power measuring device.

Fig. 8 is an external perspective view showing a state in which the main unit of the electric power measuring device is separated from the additional unit.

FIG. 9 is a schematic cross-sectional view showing a first modification of the electric power measuring device.

Fig. 10 is a schematic cross-sectional view showing a second modification of the electric power measuring device.

1. The composition of the power measuring device

The power measuring device according to an embodiment of the present invention is, for example, disposed in a ground plate such as a power distribution board or a distribution board, and is provided with a main shaft switch and a shunt switch, and is used for measuring power consumption and power of the main circuit and the shunt circuit. consumption.

As shown in FIGS. 4 to 8, the power measuring device of the present embodiment is composed of a main body unit 1A and an additional unit 1B connected to the plurality of units of the main unit 1A in response to demand.

1 and 2 are block diagrams of the body unit 1A.

The power measuring device has a method of displaying the measurement result of the power consumption on the display unit, a single-unit use method stored in the memory card, and a method of transmitting the measurement result to an external device connected via the communication line.

Fig. 1 is a view showing a wiring form in a case where the power measuring device is used in a single unit, and Fig. 2 shows a wiring form in a case where the power measuring device is connected to the management device 100 for an external device.

In general, in the initial stage of introduction of the power measuring device into the power distribution system, the power measuring device is often used in a stand-alone manner. In the case where the power measuring device is used in a stand-alone manner, in order to collect the measurement data stored in the memory card, the user must periodically go to the setting of the power measuring device to perform the operation of collecting the memory card. In the subsequent application, the user expects the measurement object to increase. If the measurement object exceeds a certain scale, in order to facilitate the collection of the measurement data, the communication line is connected between the power measuring device and the management device 100, thereby The way of communication to transmit measurement data.

The main body unit 1A constituting the electric energy measuring device according to the present embodiment includes a power measuring unit 10 (a current measuring unit 11, a voltage measuring unit 12, and a power calculating unit 13), a memory card interface 14, and a communication unit. 15. A display unit 16, a power supply circuit unit 17, and an air gap discharger (Gap Arrester) 18. Further, the main body unit 1A may include at least the electric power measuring unit 10, the communication unit 15, and the air gap discharger 18.

An output line CB4 of the current transformer 11a is connected to the current measuring unit 11. An electric wire through which a current of the measuring object flows is inserted into the core hole of the current transformer 11a. The electric current measuring unit 11 measures the current value of the measurement target based on the output signal of the current transformer 11a.

In addition, in the 3-phase 4-wire type power distribution method, each phase of the R phase, the S phase, and the T phase is measured. For the current, three current transformers 11a are required, and one circuit requires three connection portions (not shown) connected to the current transformer 11a.

Further, in the present embodiment, since the current of the three circuit components can be measured by one main unit 1A, three connection portions are set as one set, and three sets (that is, nine) connection portions are provided in the main body unit 1A.

The voltage measuring unit 12 detects the voltage applied to the circuit of the measuring object, that is, the power supply voltage of the commercial alternating current power source AC as an external power source. In the three-phase four-wire type power distribution method, each phase voltage is measured by the voltage measuring unit 12. Further, the voltage applied to the circuit of the measuring object is not limited to the voltage of the external power source.

The power calculation unit 13 periodically reads the measurement results from the current measuring unit 11 and the voltage measuring unit 12, and uses the measured values of the current and the voltage, and the phase difference between the current and the voltage, and calculates the load to obtain the load. Data such as power consumption and power consumption of the circuit. The power calculation unit 13 outputs the measurement results such as the power consumption and the power consumption amount to the memory card I/F unit 14, the communication unit 15, and the display unit 16. Further, the electric energy measurement unit 10 is configured by a current measuring unit 11, a voltage measuring unit 12, and a power calculation unit 13.

That is, the power measuring device of the present embodiment includes the electric energy measuring unit 10 that measures electric power. In the present embodiment, the electric energy measurement unit 10 is configured to measure the power consumption of the load. In addition, the electric power measured by the electric energy measurement unit 10 may be electric power (supply electric power) supplied from a power source, electric power generated by a power generating device (solar battery or the like) (power generation electric power), and electric power stored in the electric storage device. (storage power).

The memory card interface (hereinafter referred to as an I/F unit for a memory card) 14 includes, for example, a card slot in which the memory card MC1 (such as an SD card) is freely inserted. The memory card I/F unit 14 writes the measurement result to the memory card MC1 after inputting the measurement result from the power calculation unit 13, and records the power consumption and the power consumption amount of each circuit as a series in time series. Memory card MC1. Further, the power calculation unit 13 may store the measurement data such as the power consumption and the power consumption amount measured for each circuit in the main body memory (not shown).

The communication unit 15 transmits the communication line CB5 (Tx line, Rx line) on the transmission side and the reception side, which are respectively composed of twisted pairs, as shown in Fig. 2, based on the RS485 standard of the communication standard for serial communication. The external device (the management device 100 in the present embodiment) is connected to perform serial communication with the management device 100.

In the case where the management device 100 is connected to the main unit 1A, the communication unit 15 transmits the measurement result to the management device 100 after inputting the measurement result from the electric power calculation unit 13. As described below, the management device 100 is connected to the power measuring device via the communication line CB5. The power measuring device has a communication terminal (connection terminal) T15 for connection to the communication line CB5. The communication unit 15 outputs the power value measured by the power measurement unit 10 to the communication line CB5 connected to the communication terminal 15. Thereby, the communication unit 15 transmits the measurement result (the power value measured by the power amount measuring unit 10) to the management device 100.

Further, the main unit 1A transmits the conventional measurement result stored in the memory card MC1 from the communication unit 15 to the management device 100 in response to the transmission request from the management device 100. Further, the main unit 1A may transmit the conventional measurement result stored in the main body memory card from the communication unit 15 to the management device 100 in accordance with the transmission request from the management device 100.

The display unit 16 can be configured by an element such as a liquid crystal display, and displays a measurement result after inputting the measurement result from the power calculation unit 13. Further, the display unit 16 displays information such as various setting contents and operation states in addition to the measurement results. The display unit 16 may be integrated with the main unit 1A, or may be an independent device, or may be a display lamp such as a light-emitting diode.

The power supply circuit unit 17 receives power supply from the commercial AC power supply AC as an external power source through the power supply cable CB1 to generate the current measurement unit 11, the voltage measurement unit 12, the power calculation unit 13, and the memory card I/F. The operation power of the unit 14, the communication unit 15, and the display unit 16 is supplied to each part. Further, the power supply circuit unit 17 supplies an operation power supply to the extension unit 1B connected to the main unit 1A.

Here, in the circuits shown in FIGS. 1 and 2, the electric power measuring unit 10 (consisting of the current measuring unit 11, the voltage measuring unit 12, and the electric power calculating unit 13) and the high-voltage circuit of the power supply circuit unit 17 are installed. The weak electric circuit including the communication unit 15 is mounted on the second circuit board B2 on the first circuit board B1.

The ferroelectric circuit is, for example, a circuit for supplying power as power (a circuit using electric power as energy). The weak current circuit is, for example, a circuit for transmitting a power signal (a circuit using power as a signal). In general, the voltage of a strong electric circuit is higher than the voltage of a weak electric circuit. If the voltage applied to the circuit is equal to or higher than a predetermined value (48 V or 60 V), it is a strong electric circuit, and if the voltage applied to the circuit is less than a predetermined value, it is a weak electric circuit.

In addition, in FIGS. 1 and 2, the current measuring unit 11, the voltage measuring unit 12, and the power calculating unit 13 are all mounted on the first circuit board B1. However, in order to prevent a strong current from flowing into the current measuring unit 11 and the power calculation The portion 13 may be attached to the second circuit board B2.

Further, the first circuit board B1 and the second circuit board B2 may each be composed of one circuit board, or may be composed of a plurality of circuit boards. In this way, the ferroelectric system and the weak current circuit are mounted on different circuit boards. Since the first circuit board B1 of the high power system and the second circuit board B2 of the weak current system are disposed separately, the current flowing into the high-voltage circuit can be used. With the influence of voltage, the noise applied to the weak current circuit is reduced.

Further, as shown in FIGS. 1 to 4, the main body unit 1A includes connection terminals T11 to T13, T15 to T17 each composed of a screw terminal device, and a socket type connector, in order to electrically connect to an external circuit. Connector CN11. Further, in the block diagrams of Figs. 1 and 2, the drawings of the connection terminal T17 and the connector CN11 are omitted. Further, the connection terminals T11 to T13 and T15 to T17 are not limited to the screw terminal device.

The connection terminal T11 is connected to the 2-core power supply cable CB1 from the commercial AC power supply AC. The commercial AC power supply AC is supplied to the power supply circuit unit 17 through the connection terminal T11. That is, the connection terminal T11 is used to connect from an external power source (the present embodiment is a commercial AC power source AC). The power terminal of the incoming power cable (power cable CB1).

The connection terminal T12 is connected to the cable for inputting the voltage of the measurement point to the voltage measuring unit 12, and in the case of 3-phase 4-wire power distribution, the phase voltages of the R phase, the S phase, and the T phase are input through the cable CB2. . In other words, the connection terminal T12 is a terminal for voltage measurement for connecting a connection line for voltage measurement.

The connection terminal T13 as the first ground terminal is connected to the ground line CB3 that connects the power supply circuit unit 17 to the ground (ground). That is, the first ground terminal T13 is for connecting a ground line CB3 that grounds the power measuring device. In the present embodiment, the first ground terminal T13 is connected to the ground line CB3 that grounds the power supply circuit portion 17 of the power measuring device.

The connection terminal T15 is connected to the communication line CB5, and the communication line CB5 is connected between the communication unit of the management device 100 and the communication unit 15. The communication line CB5 is composed of one pair or two pairs of twisted pairs (Tx line, Rx line), and the connection terminal T15 is composed of two or four screw terminal devices. That is, the connection terminal T15 is a communication terminal for connection to the communication line CB5.

The connection terminal T16 as the second ground terminal is composed of two screw terminal devices, and each screw terminal device is connected to the shield line CB6, and the shield line CB6 is paired with one pair or two pairs of pairs constituting the communication line CB5. The stranded wire is electromagnetically shielded. That is, the second ground terminal T16 is connected to the shield line CB6 that electromagnetically shields the communication line CB5.

The connection terminal T17 and the connector CN11 are provided with an output line CB4 for connecting the current transformer 11a; the output signal of the current transformer 11a is input to the current measuring unit 11 through the connection terminal T17 or the connector CN11. In other words, the connection terminal T17 and the connector CN11 are terminals for measuring a current for connecting a connection line for current measurement. Further, the electric energy measuring instrument may be provided with at least one of the connection terminal T17 and the joint CN11.

In the present embodiment, the current measuring unit 11 can be connected to any of two types (for example, 400A and 5A) of the current transformer 11a having different measurement ranges. Input-side circuit The type of the device 11a is different, and in the current transformer 11a having a measurement range of 400 A, the output line CB4 is connected to the connection terminal T17 constituted by the screw terminal device.

Further, in the current transformer 11a having a measurement range of 5 A, a plug type joint connected to the end of the output line CB4 is connected to a joint CN11 composed of a socket type joint.

The air gap discharger 18 is composed of, for example, a discharge tube having a gas therein, and is attached to the first circuit board B1 together with the high-voltage circuit shown in FIG.

The terminal 181 of one side of the air gap discharger 18 is electrically connected to the connection terminal T13 (first ground terminal) through the wiring pattern 20 of the first circuit board B1. The other terminal 182 of the air gap discharger 18 is electrically connected to a plated through hole (not shown) provided in the first circuit board B1 through the wiring pattern 21 of the first circuit board B1.

Further, the second circuit board B2 is provided with a plated through hole (not shown) that is electrically connected to the connection terminal T16 (second ground terminal) through the wiring pattern 22 of the second circuit board B2.

The plated through holes of the first circuit board B1 and the second circuit board B2 are respectively connected to both ends of the cable CB7 by soldering, and the air gap discharger 18 is transmitted between the first ground terminal T13 and the second ground terminal T16. Gap joint.

The air gap discharger 18 is a surge protection mechanism that is connected between the first ground terminal T13 and the second ground terminal T16. The surge protection mechanism is configured to electrically connect the first ground terminal T13 and the second ground terminal T16 when a surge occurs. When a glitch occurs, for example, when the potential difference between the first ground terminal T13 and the second ground terminal T16 exceeds a predetermined threshold value. In other words, if the potential difference between the first ground terminal T13 and the second ground terminal T16 does not exceed a predetermined threshold value, the surge protection mechanism electrically insulates the first ground terminal T13 from the second ground terminal T16. When the potential difference between the first ground terminal T13 and the second ground terminal T16 is equal to or greater than a predetermined critical value, the surge protection mechanism turns on between the first ground terminal T13 and the second ground terminal T16. Further, the predetermined threshold value is a value (judgment value) for determining whether or not a glitch is generated. The established threshold value, for example, is greater than the voltage of the high-voltage circuit and less than the surge voltage.

When the power measuring unit is used in a stand-alone manner, since the connection terminal T15 is not connected to the communication line CB5, and the shield line CB6 for electromagnetically shielding the communication line CB5 is not connected to the second ground terminal T16, the communication unit 15 forms an ungrounded state.

The connection terminal T15 and the second ground terminal T16 are respectively provided in a state in which the surface of the main body unit 1A is exposed so as to be connectable to the communication line CB5 and the shield line CB6.

Therefore, when performing any work in the disk in which the main unit 1A is provided, the operator's body may come into contact with the connection terminal T15 or the second ground terminal T16, so that the static electricity carried by the operator's body may be from the connection terminal T15 or It is T16 that flows into the communication unit 15.

Even in such a case, in the present embodiment, since the first ground terminal T13 and the second ground terminal T16 are gap-engaged by the air gap discharger 18, the air gap discharger 18 can be turned on. Static electricity is conducted from the first ground terminal T13 to the ground.

Therefore, since the surge voltage or the surge current applied to the circuit component constituting the communication unit 15 is lowered, it is not necessary to use a high-voltage component to constitute the circuit component of the communication unit 15, and the cost can be reduced.

Further, in the main unit 1A of the present embodiment, when the load power consumption is measured by, for example, a three-phase four-wire type power distribution method, the electric power of three circuits can be measured, but it is desirable to measure the electric power of four or more circuits. In the case, the add-on unit 1B is connected to the body unit 1A.

The extension unit 1B can measure the electric power of the three circuits in the same manner as the main unit 1A, and the extension unit 1B can be connected to the main unit 1A and used only by adding the necessary number. Further, the extension unit 1B has a current measuring unit (not shown) of a plurality of circuit sections (for example, three circuit points), and outputs a measurement result of the current measured by the current measuring unit to the main body unit 1A.

In the main unit 1A, the power calculation unit 13 periodically reads the current measurement value of the circuit of the measurement target from the extension unit 1B, and the voltage value measured by the current measurement value and the voltage measurement unit 12 is Based on the calculation, the data such as the power consumption and the power consumption of the circuit of the measurement object are obtained by calculation.

Then, the power calculation unit 13 calculates the data such as the power consumption and the power consumption amount of the circuit to be measured by the extension unit 1B, and outputs the measurement result to the memory card I/F unit 14, the communication unit 15, and the display unit. 16 and other components.

The circuit configuration of the main unit 1A and the add-on unit 1B will be described above, and the structure of the main unit 1A and the add-on unit 1B will be described below with reference to FIGS. 3 to 8. Further, in the following description, although not specifically named, the direction of the up, down, left, and right directions is defined in the state of being mounted in the disk (that is, the direction shown in FIG. 4(a)), and the right side in FIG. 5 is described as the front side. That is, the longitudinal direction of the power measuring device (the main unit 1A and the add-on unit 1B) is the left-right direction of FIG. 4(a), and the width direction of the power measuring device is the up-and-down direction of FIG. 4(a), and the power measurement is performed. The thickness direction of the device is the left-right direction of FIG.

The main body unit 1A includes, as circuit elements, a current measuring unit 11, a voltage measuring unit 12, a power calculating unit 13, a memory card interface 14, a communication unit 15, a display unit 16, a power supply circuit unit 17, and an air gap. Electrical appliance 18, connecting terminals T11~T13, T15~T17 and connector CN11.

In the main body unit 1A, the circuit elements are mounted on the circuit board (the first circuit board B1 and the second circuit board B2).

The main body unit 1A includes a body 50 that houses a circuit board (the first circuit board B1 and the second circuit board B2) on which the circuit elements are mounted. Moreover, the body 50 is not necessary.

The body 50 of the main body unit 1A is configured by combining a main body portion 51 and a lid portion 52 each composed of a synthetic resin molded article.

The body portion 51 is formed in a rectangular box shape having an opening on the front side. The lid portion 52 is formed in a slightly box shape having an opening on the rear side, and is attached to the front side of the body portion 51 so as to cover the opening of the body portion 51. Further, the projections 51e provided on the upper side surface and the lower side surface of the main body portion 51 are fitted to the through holes 52c of the lid portion 52 to couple the main body portion 51 and the lid portion 52 (see Figs. 4 and 7).

The front surface (the right side in FIG. 5) of the lid portion 52 is provided with the segment portions 54, 55 on both sides in the width direction (up and down direction), and is disposed between the segment portion 54 and the segment portion 55 so as to protrude forward. a protruding portion 53.

As shown in Fig. 5, the back surface (the left side in Fig. 5) of the main body portion 51 is provided with a rectangular groove 51a extending in the left-right direction in the vicinity of the center in the vertical direction. The rectangular groove 51a can be inserted into a rail member (for example, a rail member standardized to a DIN standard or the like) for mounting an internal member (for example, a trunk switch or a split switch) in the disk.

The upper end surface of the rectangular groove 51a is provided with a claw portion 51b that is locked to the side piece of the rail element. On the other hand, a claw portion 56a provided at the upper end of the latch piece 56 is projected from the lower end surface of the rectangular groove 51a. The latch piece 56 is provided to be freely movable in the up-and-down direction with respect to the main body portion 51, and is continuously subjected to an upward elastic force by a spring portion (not shown).

Therefore, while the rail member is inserted into the rectangular groove 51a, the claw portion 51b is locked to the upper side piece of the rail member, and the claw portion 56a of the latch piece 56 is locked to the lower side piece of the rail member, whereby the device The body 50 forms a state of being mounted on the rail member.

Further, the lower portion of the latch piece 56 protrudes further below the lower end surface of the body 50, and when the operator pulls the lower portion of the latch piece 56 to the lower side, the claw portion 56a is pulled into the inner side of the lower end surface of the rectangular groove 51a. . Thereby, the locked state of the claw portion 56a and the rail member is released, and the body 50 can be taken out from the rail member.

The first circuit board B1 and the second circuit board B2 shown in FIG. 3 are housed inside the body 50. The first circuit board B1 of the ferroelectric system is housed in the main body portion 51, and the second circuit board B2 of the weak electric system is housed in the lid portion 52.

In other words, the body 50 includes a first case (the main body portion 51 in the present embodiment) and a second case in which the second circuit board B2 is housed (the cover in the present embodiment) Part 52). The first case (main body portion 51) has a first surface (upper surface of FIG. 3) exposed from the first circuit board B1 The first opening. The second case (cover portion 52) has a second opening that exposes the second surface (the lower surface of FIG. 3) of the second circuit board B2. The second case (cover portion 52) is attached to the first case (body portion 51) so that the second opening faces the first opening.

Among the above-described connection terminals T11 to T13, T15 to T17, and the connector CN11, the connection terminals T11 to T13 are attached to the first circuit board B1 of the high power system, and the connection terminals T15 to T17 and the connector CN11 are attached to the second circuit board of the weak current system. B2.

In other words, since the connection terminals T11 to T13 are included in the ferroelectric circuit together with the power supply circuit unit 17 and the power measurement unit 10, they are mounted on the first circuit board B1. Since the connection terminals T15 to T17 and the connector CN11 are included in the weak current system together with the communication unit 15, they are mounted on the second circuit board B2. Further, the weak current circuit further includes a memory card 1/F unit 14 and a display unit 16.

The electric wire is inserted into the connection terminals T11 and T13 through the rectangular hole 51c opened at the lower side of the main body portion 51, and the electric wire is inserted into the connection terminal T12 through the rectangular hole 51d opened at the lower side surface of the main body portion 51.

The terminal screws of the connection terminals T11 to T13 are exposed to the front side from the through holes 55a and 55b provided in the segment portion 55 on the lower side of the lid portion 52, and the terminal screws are locked by inserting a screwdriver from the through holes 55a and 55b. Thereby, the connection terminals T11 to T13 and the electric wires are connected.

Further, the communication line CB5 and the shield line CB6 are inserted into the connection terminals T15 and T16 through the through holes 52a through which the electric wires are inserted on the upper side surface of the lid portion 52.

The terminal screws of the respective connection terminals T15 and T16 are respectively exposed from the through hole 54a provided in the front surface of the segment portion 54 to the front side, and the terminal screws are locked by a screwdriver inserted from the through hole 54a, and the wires and the connection terminals can be connected. T15 and T16 are connected.

Further, the output line of the current transformer 11a is inserted into each of the connection terminals T17 through the through hole 52b. The through hole is provided on the upper side surface or the lower side surface of the lid portion 52 for inserting the electric wires.

The terminal screws of the respective connection terminals T17 are exposed from the through holes 54b of the segment portion 54 or the through holes 55c of the segment portion 55 to the front side, and the terminal screws are locked by a screwdriver inserted from the through holes 54b or 55c. Thereby, the output line is connected to the connection terminal T17.

Further, in the present embodiment, twelve connection terminals T17 are disposed in the upper segment portion 54, and six connection terminals T17 are disposed on the lower segment portion 55, and the six connection terminals T17 are arranged in a line. . The three connectors CN11 are arranged in a row and are arranged side by side with six connection terminals T17 arranged in a row. Next, the electric wire connection portions of the six connection terminals T17 are exposed from the respective through holes 52b, and the terminal screws of the six connection terminals T17 are exposed from the through holes 54b and 55c, and the three terminals CN11 and the six connection terminals T17 are arranged side by side. And exposed.

Further, on the second circuit board B2, a DIP switch 19 for setting an address and LEDs LD1 to LD4 for performing various displays are mounted.

The DIP switch 19 is exposed to the front side from the through hole 53b provided in the front surface of the protruding portion 53.

Further, the light emitted from the light-emitting diodes LD1 to LD4 is emitted to the front from the through hole provided in the front surface of the protruding portion 53.

Further, a through hole 53d for exposing the card slot SL1 of the memory card I/F portion 14 is provided on the front surface of the protruding portion 53.

Next, the configuration of the extension unit 1B will be described. The body 60 of the extension unit 1B is configured by combining the main body portion 61 and the lid portion 62 each composed of a synthetic resin molded article. The body portion 61 has a rectangular box shape with a front side opening. The lid portion 62 is formed in a slightly box shape with a rear side opening, and is attached to the front side of the body portion 61 so as to cover the opening of the body portion 61. Further, the projections 61c provided on the upper side surface and the lower side surface of the main body portion 61 are fitted into the through holes 62b of the lid portion 62, whereby the main body portion 61 and the lid portion 62 can be coupled to each other (see FIGS. 4 and 8). .

The front surface of the lid portion 62 is provided with the segment portions 64 and 65 on both sides in the vertical direction, and the table-shaped projecting portion 63 is provided between the segment portion 64 and the segment portion 65 so as to protrude forward.

Further, as shown in FIG. 6, the back surface of the main body portion 61 is provided with a rectangular groove 61a extending in the left-right direction in the vicinity of the center in the vertical direction.

The upper end surface of the rectangular groove 61a is provided with a claw portion 61b that is locked to the upper side piece of the above-described rail member (not shown). The claw portion 66a provided at the upper end of the latch piece 66 protrudes from the lower end surface of the rectangular groove 61a. The latch piece 66 is provided to be freely movable in the up-and-down direction with respect to the main body portion 61, and the spring portion (not shown) continues to receive an upward elastic force.

Therefore, in a state where the rail member is inserted into the rectangular groove 61a, the claw portion 61b is locked to the upper side piece of the rail member, and the claw portion 66a of the latch piece 66 is locked to the lower side piece of the rail member, whereby the body 60 Forms that are mounted to the track member.

Further, the lower portion of the latch piece 66 protrudes further downward from the lower end surface of the body 60, and when the operator pulls down the lower portion of the latch piece 66, the claw portion 66a is pulled into the inner side of the lower end surface of the rectangular groove 61a. Thereby, the locked state of the claw portion 66a and the rail member can be released to take out the body 60 from the rail member.

Further, the upper side wall and the lower side wall of the main body portion 61 are formed with two slits 61d open at the left end, and a flexible piece 61e is provided between the two slits 61d.

The right end of the flexible piece 61e is unilaterally supported on the side wall of the body portion 61, and the left end of the flexible piece 61e is freely deflectable in the up and down direction. Next, the left end of the flexible sheet 61e is provided with a claw portion 61f that protrudes outward.

Moreover, the right side surface of the body 60 is provided with the groove 61g in the both sides of the up-down direction. The right side surface of the body 50 of the main body unit 1A is also provided with the same groove (shown at the end of the drawing) as the extension unit 1B on both sides in the vertical direction.

Next, the main body unit 1A and the extension unit 1B are respectively coupled to the groove of the main unit 1A by being engaged with the groove of the main unit 1A in a state where they are attached to the rail elements, respectively. Further, between the additional units 1B, the claw portions 61f provided in one of the extension units 1B are engaged with the grooves 61g of the other extension unit 1B in a state in which they are attached to the rail members, thereby being connected to each other.

Inside the body 60, a substrate (not shown) in which circuit components such as a current measuring unit are mounted is housed. Similarly to the main unit 1A, the current measuring unit of the extension unit 1B includes two connection units (a connection terminal T21 and a joint CN21) that can be connected to the two types of current transformers 11a having different measurement ranges.

Next, the current measuring unit of the extension unit 1B is connected to a connection unit corresponding to the current collector selected by the magnitude of the load current, and the current value of the measurement target is measured. In the present embodiment, one of the three connection terminals T21 and the connector CN21 is set as one set by measuring one circuit of three circuit divisions (in the case of three-phase four-wire power distribution) by one extension unit 1B, and is added. Three sets of connection terminals T21 and a connector CN21 are provided in the unit 1B.

The connection terminal T21 is constituted by a screw terminal device. The segment portion 54 on the upper side of the body 60 is provided with twelve connection terminals T21, and the lower segment portion 65 is provided with six connection terminals T21, and the six connection terminals T21 are respectively arranged. Configured for a column. The three joints CN21 are arranged in a row in parallel with the six connection terminals T21 which are arranged and arranged in a row.

Then, the electric wire connecting portion of the six connecting terminals T21 is exposed from the common through hole 62a of the electric wire provided on the upper side surface or the lower side surface of the lid portion 62, and the output cable of the flow divider 11a can be inserted into the connecting terminal through the through hole 62a. The wire connection of the T21.

Further, the terminal screw of each of the six connection terminals T21 is exposed from the through hole 64a of the segment portion 64 or the through hole 65a of the segment portion 65, and the terminal screw is screwed in by a screwdriver inserted from the through hole 64a or the through hole 65a. Thereby, the connection terminal T21 is connected to the output cable.

Further, three joints CN21 juxtaposed with the six connection terminals T21 are passed through the through holes 64a, 65a. Exposed, a plug-type connector (not shown) provided on the output cable of the current transformer 11a is connected to the connector CN21.

2. Power meter action

The power measuring device according to the present embodiment has the above configuration, and the connection terminal T11 is connected to the power cable CB1 from the external power source. The connection terminal T12 is connected to the cable CB2, and the voltage of the circuit of the measurement target is input to the voltage measuring unit 12.

The main unit 1A is provided with a combination of a connection terminal T17 for current measurement of a plurality of circuit divisions and a connector CN11, and selects a current transformer 11a corresponding to a circuit current of the measurement target, and a corresponding connection terminal T17 or a connector CN11. connection.

The power calculation unit 13 reads the measurement results of the current measurement unit 11 and the voltage measurement unit 12 at a predetermined timing, and obtains the power consumption and the power consumption amount of each circuit, and displays them on the display unit 16.

Further, the power calculation unit 13 outputs the measurement result to the memory card I/F unit 14 and stores the measurement result in the memory card MC1.

In the case where the extension unit 1B is connected to the main unit 1A, the power calculation unit 13 reads the measurement current of each circuit from the extension unit 1B, and obtains the electric power using the measurement result of the measurement current and the voltage measurement unit 12. consumption.

Next, the power calculation unit 13 displays the measurement result of the measurement target according to the extension unit 1B on the display unit 16 and stores it in the memory card MC1.

Further, when the management device 100 is connected to the main unit 1A, the main unit 1A transmits the history data of the measurement result stored in the memory card MC1 from the communication unit 15 periodically or in response to a request from the management device 100. To the management device 100. The management device 100 can grasp the change trend of the power consumption due to the load based on the measurement result transmitted from the main unit 1A.

3. Power meter

As described above, the power measuring device according to the present embodiment includes the power measuring unit (consisting of the current measuring unit 11, the voltage measuring unit 12, and the power calculating unit 13), the communication unit 15, the power supply circuit unit 17, and A connection terminal T13 as a first ground terminal and a connection terminal T16 as a second ground terminal. The power measurement unit measures the power consumption of the load. The communication unit 15 outputs the measurement result of the power measurement unit to an external device (for example, the management device 100) connected via the communication line CB5. The power supply circuit unit 17 receives power supply from an external power source (for example, a commercial AC power source AC), and supplies the operation power to the power measurement unit and the communication unit 15. The connection terminal T13 as the first ground terminal is connected to the ground line CB3 for protecting the power supply circuit portion 17 from being grounded. The connection terminal T16 as the second ground terminal is provided to be connected to the shield line CB6 that electromagnetically shields the communication line CB5. Next, a gap is formed between the connection terminal T13 as the first ground terminal and the connection terminal T16 as the second ground terminal through the discharge gap (which is constituted by the air gap discharger 18 in the present embodiment).

That is, the power measuring device of the present embodiment has the following first feature. In the first aspect, the power measuring device includes: a power measuring unit 10 that measures power; a communication terminal (connection terminal) T15 for connecting to the communication line CB5; and a communication unit 15 that is measured by the power measuring unit 10. The power value is output to the communication line CB5 connected to the communication terminal 15; the first ground terminal T13 is connected to the ground line CB3 that grounds the power measuring device; and the second ground terminal T16 is used to electromagnetically connect the communication line CB5. The shielded shield wire CB6 is connected; and the surge protection mechanism (the air gap discharger 18 in the example shown in FIG. 1) is connected between the first ground terminal T13 and the second ground terminal T16.

Further, the power measuring device according to the present embodiment has the following second feature in addition to the first feature. The second feature is a surge protection mechanism configured to electrically connect the first ground terminal T13 and the second ground terminal T16 when a surge occurs. Further, in the power measuring device of the present embodiment, the second feature is an arbitrary feature.

Further, the power measuring device according to the present embodiment has the following features in addition to the first or second feature; The third special. The third feature is an electric power measuring device comprising: a power supply terminal T11 for connecting a power supply line CB1 from an external power supply (commercial alternating current power supply AC in the present embodiment); and a power supply circuit unit 17 according to the transmission and the power supply The power source line CB1 connected to the terminal T11 supplies power received from the external power source to the power amount measuring unit 10 and the communication unit 15. The first connection terminal T13 is connected to the power supply circuit unit 17. Further, in the power measuring device of the present embodiment, the third feature is an arbitrary feature.

Thereby, even in a state where the shielded wire is not connected to the connection terminal T16 (the communication unit 15 is not grounded), in the case where static electricity is applied to the connection terminal T15 or T16, since the discharge gap is turned on, the static electricity can be transmitted. 1 The ground terminal is conducted to the ground (ground). Therefore, the circuit components constituting the communication unit 15 can be protected from static electricity, and a low-voltage component can be used as the circuit component constituting the communication unit 15, so that cost can be reduced.

In the power measuring device of the present embodiment, when the shield line CB6 is not connected to the second ground terminal (the connection terminal T16), static electricity is applied to the terminal (the connection terminal T15) connected to the communication line CB5. Since the discharge gap is conducted, static electricity can be conducted from the first ground terminal (connection terminal T13) to the ground, so that the circuit components constituting the communication portion 15 can be protected from static electricity.

Further, in the present embodiment, the connection terminal T13 as the first ground terminal is connected to the ground line that protects the power supply circuit unit 17 from the ground. However, the first ground terminal may be grounded by the power measurement unit 10. In other words, the grounding wire for protecting at least one of the power supply circuit unit 17 and the power measuring unit 10 from being grounded may be connected to the first ground terminal, and the first ground terminal may be a protective high-voltage circuit. Let it be grounded. In other words, the first connection terminal T13 may be connected to the power measuring unit 10 (particularly, the voltage measuring unit 12) without being connected to the power supply circuit unit 17. Alternatively, the first connection terminal T13 may be connected to the power supply circuit unit 17 and the power measurement unit 10 (particularly, the voltage measurement unit 12).

In other words, the power measuring device according to the present embodiment may have the following fourth feature in addition to any of the first to third features. In the fourth feature, the first connection terminal T13 is connected to the electric power measuring unit 10.

Further, in the present embodiment, the discharge gap is an air gap discharger. According to the present embodiment, since the discharge gap is constituted by the air gap discharger 18, the discharge gap can be realized by easily available parts.

In other words, in addition to the features of any of the first to fourth features, the power measuring device of the present embodiment has the following fifth feature. In the fifth feature, the surge protection mechanism is a surge protection element. Further, in the power measuring device of the present embodiment, the fifth feature is an arbitrary feature.

Further, the power measuring device according to the present embodiment has the following sixth feature in addition to the fifth feature. In the sixth feature, the surge protection element is an air gap discharger. Further, in the power measuring device of the present embodiment, the sixth feature is an arbitrary feature. Here, the surge protection component is preferably an air gap discharger or a seamless discharger.

Further, for example, the pattern gap formed in the first circuit board B1 may be formed instead of the air gap discharger 18, so that the discharge gap can be realized at a low cost.

In the first modification of the power measuring device of the present embodiment, the first circuit board B1 including the high-voltage circuit including the power measuring unit 10 and the power source circuit unit 17 is mounted, and the communication unit 15 is mounted. The second circuit board B2 of the weak current circuit. The discharge gap is a pattern gap 25 arbitrarily formed between the first circuit board B1 and the second circuit board B2.

In the first modification, the surge protection mechanism is the pattern gap 25. As shown in FIG. 9, the pattern gap 25 is composed of a first conductive layer 251 and a second conductive layer 252 which form the first circuit board B1 so as to face each other with a predetermined interval Dg therebetween.

The first conductive layer 251 is electrically connected to the first ground terminal T13 attached to the first circuit board B1. The second conductive layer 252 is electrically connected to the second ground terminal T16 attached to the second circuit board B2 by a cable or the like.

The predetermined interval Dg is such that the first conductive layer 251 and the second conductive layer 252 are formed when a surge occurs. The way between the conduction is set. In other words, the predetermined interval Dg is selected such that a discharge occurs between the first conductive layer 251 and the second conductive layer 252 when a surge occurs. In other words, it is determined according to the voltage value and the current value at which the insulating insulation is generated between the first conductive layer 251 and the second conductive layer 252.

That is, the pattern gap 25 is a conductor pattern formed on the substrate so as to be opposed to each other with a predetermined interval Dg therebetween. Further, the pattern gap 25 may be formed in the second circuit board B2 on which the circuit including the communication unit 15 is mounted, or may be formed in the pattern gap of either one of the first circuit board B1 and the second circuit board B2 to constitute a discharge gap.

In other words, the first modification of the electric power measuring device according to the present embodiment has the following seventh feature in addition to any of the first to fourth features. In the seventh aspect, the power measuring device includes a circuit board (B1, B2) to which the first ground terminal T13 and the second ground terminal T16 are mounted. The surge protection mechanism includes a first conductive layer 251 connected to the first ground terminal T13 and a second conductive layer 252 connected to the second ground terminal T16. The first conductive layer 251 and the second conductive layer 252 are formed on the circuit board (B1, B2) so as to face each other with a predetermined interval Dg therebetween. The predetermined interval Dg is set such that the first conductive layer 251 and the second conductive layer 252 are electrically connected to each other when a surge occurs. Further, in the power measuring device of the present embodiment, the seventh feature is an arbitrary feature.

Further, the first modification of the electric energy measuring device according to the present embodiment has the following eighth feature in addition to the seventh feature. In the eighth aspect, the circuit board includes the first circuit board B1 and the second circuit board B2. The first ground terminal T13 is attached to the first circuit board B1. The second ground terminal T16 is attached to the second circuit board B2. The first conductive layer 251 and the second conductive layer 252 are formed on one of the first circuit board B1 and the second circuit board B2. Further, in the power measuring device of the present embodiment, the eighth feature is an arbitrary feature.

In the present embodiment, the two substrates (the first circuit board B1 and the second circuit board B2) constitute a circuit board. However, the board may be formed of one board.

Further, a second modification of the power measuring device according to the present embodiment, as shown in FIG. 10, includes: The first circuit board B1 is provided with a circuit (a strong electric circuit) including a power measuring unit (consisting of the current measuring unit 11, the voltage measuring unit 12, and the power calculating unit 13) and the power supply circuit unit 17; and a second circuit A circuit (weak current circuit) including the communication unit 15 is mounted on the substrate B2. The body 50 accommodating the first circuit board B1 and the second circuit board B2 is configured to combine the main body portion 51 and the lid portion 52. The first circuit board B1 is housed in one of the main body portion 51 and the lid portion 52 (the main body portion 51 in the present embodiment), and the second circuit board B2 is housed in the other of the main body portion 51 and the lid portion 52 (this embodiment) In the aspect, the cover portion 52). In the first circuit board B1 and the second circuit board B2, in a state in which the main body portion 51 and the lid portion 52 are combined, the conductive protrusions 23 and 24 that face each other are provided through a predetermined gap. The protrusions 23 and 24 constitute a discharge gap.

In the second modification, as shown in FIG. 10, in the state where the main body portion 51 and the lid portion 52 are combined with each other, the first circuit board B1 and the second circuit board B2 are provided with conductive projections facing each other with a predetermined gap therebetween. The portions 23, 24, and in this way, replace the air gap discharger 18. In other words, in the second modification, the surge protection mechanism is disposed so as to face each other with a predetermined interval Lg therebetween, and is composed of the first protrusion 23 and the second protrusion 24 having conductivity.

The first projection 23 is disposed on a surface (first surface, upper surface in FIG. 10) of the first circuit board B1 that faces the second circuit board B2. The protrusion (first protrusion) 23 provided on the first circuit board B1 is electrically connected to the connection terminal T13 as the first ground terminal through the wiring pattern 20.

The second protrusion 24 is disposed on a surface (the second surface, the lower surface of FIG. 10 ) of the second circuit board B2 that faces the first circuit board B1 . The protrusion (second protrusion) 24 provided on the second circuit board B2 is electrically connected to the connection terminal T16 as the second ground terminal through the wiring pattern 22.

Next, the connection terminal T13 as the first ground terminal and the connection terminal T16 as the second ground terminal pass through the discharge gap formed by the protruding portions 23 and 24 to form a gap joint.

In other words, the second modification of the power measuring device according to the present embodiment has the following ninth feature in addition to any of the first to fourth features. In the ninth feature, the power measuring device has The first circuit board B1 including the first surface (the upper surface in FIG. 10) includes the second circuit board B2 on the second surface (the lower surface in FIG. 10) facing the first surface. The first ground terminal T13 is attached to the first circuit board B1. The second ground terminal T16 is attached to the second circuit board B2. The surge protection mechanism has a first protrusion 23 and a second protrusion 24. The first protrusion 23 is electrically connected to the first ground terminal T13 while being disposed on the first surface of the first circuit board B1. The second protrusions 24 are disposed on the second surface of the second circuit board B2 so as to face the first protrusions 23 with a predetermined interval Lg therebetween, and are electrically connected to the second ground terminal T16. The predetermined interval Lg is set such that the first protrusion 23 and the second protrusion 24 are electrically connected when a surge occurs. Further, in the power measuring device of the present embodiment, the ninth feature is an arbitrary feature.

Thereby, even if the shield line CB6 is not connected to the connection terminal T16 (the communication unit 15 is not grounded), insulation is generated between the protrusions 23 and 24 in the case where static electricity is applied to the connection terminal T15 or T16. Destruction causes the protrusions 23, 24 to be electrically connected.

Therefore, static electricity applied to the communication unit 15 can be introduced into the ground from the first ground terminal T13, and the surge voltage and the surge current applied to the circuit components constituting the communication unit 15 can be reduced. Therefore, it is possible to use a component having a low withstand voltage as a circuit component constituting the communication unit 15, and it is possible to reduce the cost.

Further, the second modification of the electric power measuring device according to the present embodiment has the following tenth feature in addition to the ninth feature. In the tenth aspect, the power measuring device includes a first case (the main body portion 51 in the present embodiment) in which the first circuit board B1 is housed, and a second case in which the second circuit board B2 is housed (this embodiment) In the sample, the cover portion 52). The first case has a first opening (an opening on the upper side in FIG. 10) that exposes the first surface of the first circuit board B1. The second case has a second opening (an opening on the lower side in FIG. 10) that exposes the second surface of the second circuit board B2. The second casing is attached to the first casing so that the second opening faces the first opening. Further, in the power measuring device of the present embodiment, the tenth feature is an arbitrary feature.

Moreover, the gap (predetermined interval) Lg between the tip end of the protrusion portion 23 and the tip end of the protrusion portion 24 is set such that the first protrusion portion 23 and the second protrusion portion 24 are electrically connected to each other when a surge occurs. In other words, the predetermined interval Lg is at the first protrusion 23 and the second protrusion when a surge occurs. The choice between the 24 is made. In other words, the gap length Lg may be determined in accordance with a voltage value and a current value which cause dielectric breakdown between the protrusions 23 and 24.

10‧‧‧Power Measurement Department

11‧‧‧ Current Measurement Department

11a‧‧‧ current comparator

12‧‧‧Voltage measurement department

13‧‧‧Power Calculation Department

14‧‧‧I/F Department for Memory Cards

15‧‧‧Communication Department

16‧‧‧Display Department

17‧‧‧Power Circuit Division

18‧‧‧air gap arrester

B1‧‧‧1st circuit substrate

B2‧‧‧2nd circuit substrate

CB1‧‧‧Power cable

CB2‧‧‧ cable

CB3‧‧‧ Grounding wire

CB4‧‧‧ output line

CB5‧‧‧ communication line

MC1‧‧‧ memory card

T11, T12, T13, T15, T16‧‧‧ connection terminals

Claims (10)

A power measuring device comprising: a power measuring unit for measuring power; a communication terminal for connecting a communication line; and a communication unit for outputting the power value measured by the power measuring unit to the communication terminal The communication line; a first ground terminal for connecting a grounding wire for grounding the power measuring device; a second grounding terminal for connecting a shielding wire for electromagnetically shielding the communication line; a surge protection mechanism, Connected between the first ground terminal and the second ground terminal. The electric power measuring device according to claim 1, wherein the surge protection mechanism is configured to electrically connect the first ground terminal and the second ground terminal when a surge occurs. The power measuring device of claim 1, wherein the surge protection mechanism is a surge protection component. The power measuring device of claim 3, wherein the surge protection element is an air gap discharger. The power measuring device according to claim 1, further comprising: a circuit board on which the first ground terminal and the second ground terminal are mounted; and the surge protection mechanism having a first ground terminal connected thereto a conductive layer and a second conductive layer connected to the second ground terminal; the first conductive layer and the second conductive layer are formed on the circuit board so as to face each other with a predetermined interval; the predetermined interval The method is set such that the first conductive layer and the second conductive layer are electrically connected when a surge occurs. The power measuring device according to claim 5, wherein the circuit board includes a first circuit board and a second circuit board; the first ground terminal is mounted on the first circuit board, and the second ground terminal is The second conductive substrate and the second conductive layer are formed on one of the first circuit substrate and the second circuit substrate. The power measuring device according to claim 1, further comprising: a first circuit substrate having a first surface; and a second circuit substrate having a second surface facing the first surface; the first ground The terminal is mounted on the first circuit board, and the second ground terminal is mounted on the second circuit board. The surge protection mechanism includes a first protrusion and a second protrusion, and the first protrusion is disposed in the first The first surface of the circuit board is electrically connected to the first ground terminal, and the second protrusion is disposed on the second surface of the second circuit board, and is spaced apart from the first protrusion by a predetermined interval The two ground terminals are electrically connected to each other, and the predetermined interval is set such that the first protrusion and the second protrusion are electrically connected when a surge occurs. The electric energy measuring device according to claim 7, further comprising: a first casing accommodating the first circuit board; and a second casing accommodating the second circuit board; the first casing having the first casing a first opening in which the first surface of the first circuit board is exposed; the second housing has a second opening exposing the second surface of the second circuit board, and the second housing is configured to be the second opening The opening and the first opening are opposed to each other and attached to the first casing. The power measuring device of claim 1, further comprising: a power terminal for connecting to a power line from an external power source, the power circuit portion being configured according to the power line connected to the power terminal The electric power received by the external power source supplies electric power to the electric energy measuring unit and the communication unit; and the first ground terminal is connected to the power supply circuit unit. The power measuring device according to claim 1, wherein the first ground terminal is connected to the power measuring unit.