JP2001025153A - Ground leakage alarm device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a ground leakage alarm device itself by fitting a switch and a switch status detection part in a test circuit part, and increasing the gain of an input signal with a gain adjusting part in a ground leakage detection part in passing test current with the switch depressed. SOLUTION: A circuit part of a ground leakage alarm 3 consists of a ground leakage detecting part 3-1, a DC power supply part 3-2, an AC power supply part 3-3, an alarm part 3-4, a limiting resistance 3-5, a push button switch 3-6 for test, and a push-button switch status detecting part 3-7 for test. The ground leakage detection part 3-2 of the ground leakage alarm 3 consists of a ground leakage measuring part 3-11, a gain adjusting part 3-14, a sensitivity setting part 3-12, and an alarm output part 3-13. As a result, when passing a test current with the push-button switch 3-6 for test depressed, the gain of an input signal is increased with the gain-adjusting part 3-14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test circuit for periodic inspection of a leakage alarm device for detecting a ground line current or a zero-phase current of an AC circuit.

[0002]

2. Description of the Related Art A conventional example will be described with reference to a block diagram of a leakage alarm device shown in FIG. In the figure, i _0t is a test current supplied to the primary side of the current transformer when the test push-button switch of the earth leakage alarm device is pressed. When the test current is supplied with a current higher than the sensitivity current of the leak alarm, the leak alarm issues an alarm and the leak alarm can be tested.

[0003]

However, in the above-described conventional configuration, inspection including current transformers such as disconnection of a current transformer or a lace short cannot be performed, and inspection including current transformers cannot be performed. It is necessary to increase the current capacity of the test push-button switch and to prepare a large test power supply for supplying the test current in the earth leakage alarm.

[0004]

SUMMARY OF THE INVENTION A first means of the present invention is a current transformer having a leakage current detection winding and a test current winding, and a leakage alarm having a leakage detection section and a test circuit section. Wherein the test circuit unit has a switch and a switch state detection unit, and the leakage detection unit receives an input of a test current when the switch is pressed, and inputs the test current by a gain adjustment unit. This has the effect of increasing the signal gain.

[0005] A second means of the present invention is a leakage alarm having a current transformer provided with a leakage current detection winding and a test current winding, and a leakage alarm provided with a leakage detection section and a test circuit section. The test circuit unit has a switch and a switch state detection unit, and the leakage detection unit supplies a test current when the switch is pressed, and the switch state detection unit detects the switch state. It has an effect of detecting and detecting the state, and adjusting the sensitivity level by the test sensitivity adjustment unit.

A third means of the present invention is a leakage alarm device having a current transformer provided with a leakage current detection winding and a test current winding, and a leakage alarm provided with a leakage detection section and a test circuit section. Wherein the test circuit unit has a switch and a switch state detection unit, and the leakage detection unit is configured to operate the leakage measurement unit, the sensitivity setting unit, the alarm output unit, the gain adjustment unit or the test sensitivity setting unit, and the switch operation before. And a fault detection unit after operation and an abnormal alarm output unit. If the alarm is normal, it has the effect of issuing a leakage alarm output.

(Embodiment 1) FIG. 1 is a block diagram of the first embodiment. The same reference numerals in the drawings denote the same components, and a description thereof will be omitted. In the figure, reference numeral 1 denotes a ground wire of an AC circuit, and 2 denotes a current transformer provided with a leakage current detection winding 2-1 and a test winding 2-2 through which a test current flows.

Reference numeral 3 denotes a leakage alarm device, 3-1 a leakage detection unit, 3-2 a DC power unit, 3-3 an AC power unit, 3-4.
, A limit resistor 3-5, a test push button switch 3-6, and a test push button switch state detector 3-7.

As shown in FIG. 2, the leakage detecting section 3-1 comprises a leakage measuring section 3-11, a gain adjusting section 3-14, a sensitivity setting section 3-12, and an alarm output section 3-13. Is connected to a current transformer input, and the gain adjustment unit is connected to a test push button switch state detection unit.

Next, the operation of the above configuration will be described.

[0011] In the conventional example, since the gain of the earth leakage measuring unit 3-11 in FIG. 2 is set so that the ground line current i ₀ operates from 0.1 A to 1 A, the test winding of the current transformer 2 is used. 2
-2, a test current of 1 A or more must be passed. In this case, when the test push button switch 3-6 is pressed, the AC current supplied from the AC power supply section 3-3 is limited by the limiting resistor 3.
The current flows through the test winding 2-2 of the current transformer 2 via -5.

The test current is tens of milliamps,
In addition to reducing the test current in the conventional example to several tenths, the gain of the gain switching unit 3-12 is switched so as to increase. It is possible to confirm that the alarm works normally.

(Embodiment 2) FIG. 3 shows Embodiment 2 of the present invention.
2 is a block diagram of the leakage detection unit 3-1. The overall configuration is the same as that of the first embodiment shown in FIG. 1, and the difference is a component of the leakage detection unit 3-1. The gain adjustment unit 3-14 has the configuration of the test sensitivity setting unit 3-15 in FIG. 3, and its operation will be described below.

According to this configuration, as in the first embodiment, the earth leakage measuring unit 3-11 adjusts the ground line current i ₀ from 0.1A to 1A.
In the conventional example, a test current of 1 A or more must be applied to the test winding 2-2 of the current transformer 2 because the gain is set to operate at about the same level. When the switch 3-6 is pressed, the AC current supplied from the AC power supply unit 3-3 is supplied to the current transformer 2 via the limiting resistor 3-5.
Of the test winding 2-2.

The test current is tens of milliamps,
The test current of the conventional example is set to several tenths, and the current value is directly measured by the electric leakage measuring unit 3-11. However, when the test push button switch 3-6 is pressed, the alarm level is the sensitivity at the steady state. From the set value of the setting unit 3-12, the test sensitivity setting unit 3-1
The setting value is switched to 5.

Therefore, since the leakage detecting section operates with a small test current, the leakage detecting section operates at the current transformer output by the test current, issues an alarm output, and confirms that the leakage alarm operates normally. It is something that can be confirmed.

In the above description, the sensitivity setting section is switched from the steady state to the sensitivity setting section for testing. However, in the case where the leakage alarm is constituted by a microcomputer, if the setting section is provided on a program, There is no need to provide a special hard-wired switching unit.

(Embodiment 3) FIG. 4 shows Embodiment 3 of the present invention.
FIG. 2 is a block diagram of a leakage detection unit 3-1 of FIG.
5 is a gain switching unit or a test sensitivity setting unit 3 shown in FIG.
16 are the same as those described above, and the difference is the components of the electric leakage detection unit 3-1. Specifically, before and after the operation of the gain switching unit 3-14 of FIG. 2 or the test push button switch of FIG. This is provided with a later-described leakage detection section 3-17.

The purpose is to prevent the current transformer output from being output if the test current flowing when the test push button switch 3-16 is pressed is always flowing in the ground line in the installed state in the opposite phase. This operation will be described below with reference to the flowchart of FIG.

5 and 6, i ₀₁ is a measured value of the ground line current, and i ₀₂ is a measured value of a combined current of the ground line current after the operation of the test push button switch and the test current i _0t. Is naturally the same as the test current when the ground line current is zero ampere, but when the ground line current is flowing, it is increased or decreased by the phase difference between the ground line current and the test current.

Next, i _0S1 is the first threshold value in the sensitivity setting section of FIG. 4, and i _0S2 and i _0S3 are the second and third threshold _values in the gain adjustment section or the test sensitivity setting section 3-16 of FIG. The flowchart in FIG. 5 will be described as the threshold value of.

First, the ground line current i ₀₁ before the test push button switch is first pressed is measured from the current transformer output (S
1) Then, it is determined whether or not the test push button switch is pressed (S2).

If the switch is not pressed,
Compare the ground line current i ₀₁ with the first threshold value i _0S1 (S
3) When i ₀₁ exceeds i _0S1 , an alarm is issued to the earth leakage alarm (S5).

When the test push button switch is pressed, the ground line current i ₀₁ is compared with the second threshold value i _0S2 (S4).

As a result, if i ₀₁ exceeds i _0S2 , an alarm is issued to the earth leakage alarm (S5). If i ₀₁ does not exceed i _0S2 , the ground line current i ₀₁ and the test push button switch are depressed. the i ₀₂ obtained by synthesizing the test current i ₀ t measured from the current transformer output (S6), compares it than i ₀₂ and the third threshold value i _0S3 (S7).

As a result, when i ₀₂ exceeds i _0S3 , an alarm is issued to the earth leakage alarm (S5).
It issues an abnormal alarm (S8).

As can be seen from the above description, when the test push button switch is not pressed, when the first threshold value is exceeded,
The test push-button switch is issued respectively leakage alarm when pressed, also is i ₀₂ to i ₀₂ is when the following third threshold to trigger an alarming an abnormality of current transformers or earth leakage alarm When the value exceeds the third threshold value, it is regarded as normal and a short-circuit warning is issued.

Here, even if the abnormal alarm is not issued, when the test push button switch 3-6 is pressed, a leakage alarm is always issued if the current transformer or the leakage alarm is normal. Yes, and therefore, if the leakage alarm is not issued at this time, it may be considered that the current transformer or the leakage alarm is abnormal.

[0029]

As is apparent from the above description, according to the first means of the present invention, the capacity of the test push button switch and the test power supply of the leakage alarm can be reduced, and therefore the leakage alarm itself can be downsized. .

Further, there is an effect that inspection including reliability of the current transformer can be performed by a small-capacity test current.

Next, according to the second means of the present invention, the function having the same effect as the first means can be realized by the test operation sensitivity setting means without providing the gain switching circuit of the first means. Have.

Further, according to the third means of the present invention, the leakage current having the opposite phase to the test current always flows, and when the test push button switch is operated, the output of the current transformer is canceled and becomes close to zero ampere. This also has an effect that the function of the test push button switch can be correctly realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a ground fault warning device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a ground fault detecting unit according to the first embodiment;

FIG. 3 is a block diagram of a ground fault detecting unit according to the second embodiment;

FIG. 4 is a block diagram of a ground fault detecting unit according to the third embodiment;

FIG. 5 is a flowchart for explaining the operation of an electric leakage detector in the third embodiment.

FIG. 6 is a configuration diagram of an earth leakage warning device according to the third embodiment.

FIG. 7 is a block diagram of a conventional earth leakage warning device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground wire 2 Current transformer 3 Leakage alarm 3-6 Test pushbutton switch 3-7 Test pushbutton switch state detection part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Kondo 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. DA01 DC03 GA01

Claims (3)

[Claims] 1. A leakage alarm device comprising: a current transformer provided with a leakage current detection winding and a test current winding; and a leakage alarm provided with a leakage detection unit and a test circuit unit. The unit has a switch and a switch state detection unit,
An electric leakage alarm device, comprising: a leakage adjusting unit that increases a gain of an input signal when a test current is supplied when the switch is pressed. 2. A leakage alarm device comprising: a current transformer provided with a leakage current detection winding and a test current winding; and a leakage alarm provided with a leakage detection unit and a test circuit unit. The unit has a switch and a switch state detection unit,
The leakage detection unit includes a test sensitivity adjustment unit that applies a test current when the switch is pressed, detects the switch state with the switch state detection unit, and adjusts a sensitivity level when the state is detected. Leakage alarm device. 3. A leakage alarm device comprising: a current transformer provided with a leakage current detection winding and a test current winding; and a leakage alarm provided with a leakage detection unit and a test circuit unit. Has a switch and a switch state detection unit, and the leakage detection unit includes a leakage measurement unit, a sensitivity setting unit, an alarm output unit, a gain adjustment unit or a test sensitivity setting unit, and a leakage determination unit before and after the switch operation. And a fault alarm output unit. The switch status detection unit and the fault detection result before and after the switch operation and the fault detection result status after the switch operation indicate that if the current transformer and the leak alarm device are normal, An earth leakage alarm device that issues an alarm output.