JPH08220154A - Electronic watthour meter - Google Patents

Abstract

PURPOSE: To enhance reliability against surge voltage exceeding a regulation level without requiring any additional component. CONSTITUTION: Discharge parts 18a, 18b are formed in the signal paths 17a, 17b between voltage input parts 19a, 19b and a voltage signal detector 15 on a printed wiring board. Consequently, a surge voltage exceeding a regulation level is discharged at the discharge parts 18a, 18b without requiring any additional component without having any effect on the internal circuit of an electronic watthour meter 11'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic watt-hour meter for measuring the amount of electric power.

[0002]

2. Description of the Related Art A conventional electronic watt hour meter will be described with reference to FIG. The electronic watt-hour meter 11 is connected to the power source side via the terminals 1S and 2S of the terminal portion 12, and has terminals 1L and 2S.
It is connected to the load side via L. Load current is CT1
It is converted into a low current value via 4 and input to the current input unit I1 of the electric energy calculation circuit 13. The power supply voltage is converted into a low voltage value by the voltage signal converter 15 and input to the voltage input unit V1 of the power amount calculation circuit 13. In addition, the power amount calculation circuit 13
Operates with the potentials of the terminals 2S and 2L of the terminal portion 12 as the reference potential G. The power amount calculation circuit 13 and the voltage signal converter 15 are mounted and wired on the printed wiring board 16, and the power line 2
The line voltage of 1 is the voltage input section 19a on the 1 side of the printed wiring board 16.
And from the second side voltage input section 19b to the voltage signal converter 15 via the first side wiring pattern 17a and the second side wiring pattern 17b.

When a surge voltage is applied between the power lines 21 due to lightning or the like, the surge voltage resistance standard 7
With a voltage from kV to about 10 kV including a design margin, the withstand voltage of the voltage signal converter 15 and the 1-side wiring pattern 17a are set so that there is no abnormality such as discharge or destruction at any place of the watt hour meter 11. The distance from the second side wiring pattern 17b is ensured. However, when a surge voltage exceeding the standard, such as 10 kV or more, is applied, the voltage converter 15 is broken or discharge occurs in a place where the insulation distance is small. In particular, if the discharge enters the electric power amount calculation circuit 13, the circuit component may be broken and the stored value of the integrated electric power amount may disappear.

[0004]

As described above, even if a surge voltage of the standard of the watt hour meter is applied between the power lines, it does not break down, but if an excessive surge voltage that greatly exceeds the standard is applied. If the electric current is discharged through the electric energy calculation circuit, the surge current may destroy the electronic circuit, and the stored value of the integrated electric energy may disappear. There is also a method of providing a surge absorbing element on the voltage input side of the voltage signal converter so that the surge voltage due to lightning does not enter the electric energy calculation circuit, but it is not preferable in terms of cost to add a component as a measure against the standard.

The present invention has been made in view of the above,
For that purpose, without adding new parts,
It is an object of the present invention to provide an electronic watt-hour meter with improved reliability against surge voltage exceeding the standard.

[0006]

In order to achieve the above object, the present invention as set forth in claim 1, is an electronic device including a voltage signal detector for detecting a line voltage of a power line mounted on a printed wiring board. In the watt hour meter, the gist is that the discharge portion is formed in the signal path from the voltage input portion provided on the printed wiring board to the voltage signal detector.

According to a second aspect of the present invention, in the first aspect of the invention, when the power line is a single-phase two-wire type, a pair of wiring patterns from the voltage input unit to the voltage signal detector is provided. The gist is that the wiring pattern is formed as a narrow space in the middle of the space.

According to a third aspect of the present invention, in the invention according to the first aspect, when the power line is a single-phase three-wire type, three wiring patterns from the voltage input unit to the voltage signal detector are provided. The gist is that, in the middle of the step, the wiring patterns are formed as narrow spacing portions that are narrowed so as to be equidistant from each other.

According to a fourth aspect of the present invention, in the invention according to the first aspect, when the power line is a single-phase two-wire type, the discharge part is formed as a narrow space part in which a space between the pair of voltage input parts is narrowed. What is done is the summary.

[0010]

According to the first aspect of the present invention, the discharge portion is formed in the signal path from the voltage input portion of the printed wiring board to the voltage signal detector, so that a nonstandard component is not used without using new parts. The surge voltage is discharged in the discharge section so that the internal circuit of the electronic watt hour meter is not affected.

According to the second aspect of the present invention, when the power line is a single-phase two-wire type, the discharge part is provided in the middle of a pair of wiring patterns from the voltage input part to the voltage signal detector. By forming the pattern as a narrow space with a narrow space, a non-standard surge voltage is discharged at the discharge part without using new parts, and it does not affect the internal circuit of the electronic watt-hour meter. ing.

According to the present invention of claim 3, when the power line is a single-phase three-wire type, the discharge part is provided in the middle of three wiring patterns from the voltage input part to the voltage signal detector. By forming the wiring patterns so as to have a narrow spacing so that they are equidistant from each other, a non-standard surge voltage is discharged at the discharge portion without using a new component, and the electronic energy meter It does not affect the internal circuit.

According to the present invention of claim 4, when the power line is a single-phase two-wire type, the discharge part is formed as a narrow space part in which the space between the pair of voltage input parts is narrowed. A non-standard surge voltage is discharged at the discharge section without using new parts so that the internal circuit of the electronic watt-hour meter is not affected.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are views showing the configuration of the first embodiment of the present invention. The feature is that a discharge point with a short distance between lines is provided in the middle of a pair of wiring patterns 17a and 17b from the voltage input portions 19a and 19b of the printed wiring board 16 to the voltage signal converter 15 which constitutes a voltage signal detector. 1
8a and 18b are formed. This will be specifically described with reference to FIG.

FIG. 2 shows the voltage signal converter 15 from the first side voltage input section 19a and the second side voltage input section 19b of the printed wiring board 16.
It is the block diagram which expanded to. Voltage signal converter 15
Is a high resistance 22 and a low resistance 23 connected in series,
The voltage signal can be obtained as the voltage of the low resistance 23 divided by the ratio of the resistance values of the high resistance 22 and the low resistance 23. From the voltage input units 19a and 19b to the voltage signal converter 1
Wiring up to 5 is performed by the 1-side wiring pattern 17a and the 2-side wiring pattern 17b, and the 1-side wiring pattern 17a and the 2-side wiring pattern 17b are respectively the 1-side discharge points 18a and 2 sides of the portions where the distance between them is small. A discharge point 18b is provided. The distance between the discharge points does not discharge at a voltage of 7 kV, which is the standard of the surge voltage of the watt hour meter 11 ', but changes a little depending on temperature and humidity, atmospheric pressure, etc., but discharges at an excessive voltage of 10 kV or more, for example. There is about 7 mm.

In FIGS. 1 and 2, the same parts as those in FIG. 7 are designated by the same reference numerals.

Next, the operation of this embodiment will be described.

When a surge voltage such as lightning occurs between the power lines 21, the voltage is also applied between the voltage input portions 19a and 19b of the printed wiring board 16. This voltage is the electricity meter 11 '
With a voltage of 7 kV of the standard of 10 kV to a voltage of about 10 kV including a design margin, discharge does not occur at any place and parts such as the voltage signal converter 15 are not broken.

On the other hand, when the surge voltage greatly exceeds the standard such as 10 kV or more, the discharge points 18a and 2 provided on the first side wiring pattern 17a before reaching the excessive voltage.
Since the discharge is generated between the discharge point 18b provided on the side wiring pattern 17b, the voltage signal converter 15 is not destroyed, or the internal electronic circuit is not destroyed by discharging through the electric energy calculation circuit 13.

Therefore, according to the present embodiment, even if a surge voltage that greatly exceeds the specifications of the watt-hour meter is applied, the internal circuit is always discharged at the discharge point provided on the printed wiring board before the overvoltage is reached. Since it is protected, the electric energy calculation circuit is not destroyed and the measured value is not lost. Further, since the discharge part may adjust the wiring pattern shape of the printed wiring board, it is not necessary to add a component such as a surge absorbing element.

FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention. The feature is that the space between the power input portions 19a and 19b of the printed wiring board 16 is narrowed to reduce the discharge points 18a,
18b also serves as the role of 18b. 3 that are the same as those in FIG. 2 are designated by the same reference numerals.

Therefore, according to the present embodiment, in addition to the effect similar to that of the first embodiment described above, it is not necessary to form a separate pattern for forming a discharge point, so that the wiring can be formed. Work efficiency can be improved.

FIG. 4 and FIG. 5 are views showing the configuration of the third embodiment of the present invention. The feature is that the power line 21
Is a single-phase three-wire type, the voltage input unit 1 of the printed wiring board 16
3 from 9a, 19b, 19c to the voltage signal converter 15
In the middle of the wiring patterns 17a, 17b, 17c of the book, the discharge points 18 are formed so that the distance between the lines is shortened so that they are evenly spaced from each other.
a, 18b, 18c are formed.

In the case of the single-phase three-wire system, since the electric powers on the first side and the third side are summed up, the third side voltage signal converter 42 and the third side current signal transformer 41 are added, and the third side wiring pattern 17c and the discharge are formed. A point 18c is provided. Then, the discharge points in this case are 1 side and 2 side, 2 side and 3 side and 1 side as shown in FIG.
The discharge points 19a, 19b, 19c are arranged in a regular triangular shape so that an excessive surge voltage between any of the three and three sides can be discharged. In FIG. 5, the second side wiring pattern 17b is indicated by a dotted line in the printed wiring board 16.
This is because of the wiring pattern on the back side of. Further, in FIGS. 4 and 5, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals.

Therefore, according to the present embodiment, even if a surge voltage that greatly exceeds the specifications of the watt-hour meter is applied, the internal circuit is always discharged at the discharge point provided on the printed wiring board before the overvoltage is reached. Since it is protected, the electric energy calculation circuit is not destroyed and the measured value is not lost. Further, since the discharge part may adjust the wiring pattern shape of the printed wiring board, it is not necessary to add a component such as a surge absorbing element. Further, in the case of the 3-wire type, the 1 side and the 2 side, the 2 side and the 3 side
Side, 1 side and 3 side three discharge parts are required,
These can be gathered in one place, and space can be saved.

FIG. 6 is a diagram showing the configuration of the fourth embodiment of the present invention. The feature is that a pair of wiring patterns 17a and 17b extending from the voltage input portions 19a and 19b of the printed wiring board 16 to the voltage signal converter 15 are formed with a narrow interval, and the surfaces thereof are opposed to each other. This is because the non-resist portions 61a and 61b facing each other are formed as discharge points by being covered with an insulating resist agent except for.

Therefore, according to this embodiment, the same effect as that of the above-mentioned first embodiment can be exhibited.

[0029]

As described above, according to the present invention as set forth in claim 1, a new discharge portion is formed in the signal path from the voltage input portion of the printed wiring board to the voltage signal detector. A surge voltage that exceeds the standard is added without adding new parts, because a non-standard surge voltage is discharged in the discharge section without using any parts to prevent the internal circuit of the electronic watt-hour meter from being affected. Reliability can be improved.

According to the second aspect of the present invention, when the power line is a single-phase two-wire type, the discharge part is provided in the middle of a pair of wiring patterns from the voltage input part to the voltage signal detector. By forming it as a narrow part that narrows the interval of,
Without using new parts, a non-standard surge voltage is discharged in the discharge part so that it does not affect the internal circuit of the electronic watt-hour meter, so without adding new parts,
The reliability with respect to surge voltage exceeding the standard can be improved.

According to the present invention as set forth in claim 3, when the power line is a single-phase three-wire type, the discharge part is provided in the middle of three wiring patterns from the voltage input part to the voltage signal detector. By forming the wiring patterns as narrow spaces so that they are equidistant from each other, a non-standard surge voltage is discharged at the discharge part without using new parts, and the inside of the electronic watt-hour meter is discharged. Since it does not affect the circuit, even if it is a single-phase three-wire system, without adding new parts,
The reliability with respect to surge voltage exceeding the standard can be improved.

According to the fourth aspect of the present invention, in the case where the power line is a single-phase two-wire type, the discharge part is formed as a narrow space part in which the space between the pair of voltage input parts is narrowed. A surge voltage that exceeds the standard is added without adding new parts, because a non-standard surge voltage is discharged at the discharge part without affecting the internal circuit of the electronic watt-hour meter. The reliability with respect to the voltage can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an electronic watt hour meter according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a part of details of FIG. 1;

FIG. 3 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an electronic watt hour meter according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a part of details of FIG. 4;

FIG. 6 is a diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a conventional electronic watt-hour meter.

[Explanation of symbols]

 11, 11 'Electronic watt-hour meter 12 Terminal portion 13 Electric energy calculation circuit 14 CT 15 Voltage signal converter 16 Printed wiring board 17a 1 side wiring pattern 17b 2 side wiring pattern 17c 3 side wiring pattern 18a 1 side discharge point 18b 2 Side discharge point 18c 3 side discharge point 19a 1 side voltage input section 19b 2 side voltage input section 19c 3 side voltage input section 21, 21 'Power line 22 High resistance 23 Low resistance 41 3 side current signal transformer 42 3 side voltage signal converter 61a, 61b Non-resist part

Claims (4)

[Claims] 1. An electronic watt-hour meter comprising a voltage signal detector for detecting a line voltage of a power line mounted on a printed wiring board, wherein a voltage signal detector is provided from a voltage input section provided on the printed wiring board. An electronic watt-hour meter characterized in that a discharge part is formed in the signal path up to. 2. When the power line is a single-phase two-wire type, the discharge part is a narrow part in which a space between the wiring patterns is narrowed in the middle of a pair of wiring patterns from the voltage input part to the voltage signal detector. The electronic watt-hour meter according to claim 1, wherein the electronic watt-hour meter is formed. 3. In the discharging section, when the power line is a single-phase three-wire type, the wiring patterns are equidistant from each other in the middle of the three wiring patterns from the voltage input section to the voltage signal detector. The electronic watt-hour meter according to claim 1, wherein the electronic watt-hour meter is formed as a narrowed space. 4. The electronic device according to claim 1, wherein the discharge part is formed as a narrow space part in which a space between the pair of voltage input parts is narrowed when the power line is a single-phase two-wire system. Electricity meter.