JP6137982B2 - Earth leakage breaker - Google Patents

Description

  The present invention relates to a leakage breaker provided with a test device for performing a leakage operation test.

The ground fault circuit breaker needs to include a test device for passing a simulated current to the detection device in order to periodically test its operation capability.
On the other hand, in order to prevent unnecessary operation due to harmonic components of an electric circuit, for example, switching noise of an inverter, a detection device is known that includes a low-pass filter (see, for example, Patent Document 1).
In addition, in order to prevent an unnecessary operation due to a surge component, for example, a lightning strike, one having a built-in waveform width detection function is known.
For this reason, a conventional earth leakage circuit breaker test apparatus is known in which a pseudo alternating current signal in the vicinity of a commercial frequency, for example, a sine wave, a rectangular wave, a triangular wave, or the like is applied to a zero-phase current transformer to check its operation. (For example, refer to Patent Document 2).

JP 2007-220281 A JP 2003-219552 A

As described above, the test apparatus supplies a pseudo AC signal to the zero-phase current transformer, but the rated sensitivity current (operating current) of the earth leakage breaker is, for example, 30 mA, 100 mA, 500 mA, etc. The current is very large with respect to mA.
For this reason, the power supply circuit must be able to withstand this consumption current, and there is a problem that it is difficult to reduce the size and thickness of the power supply circuit.

  In addition, in order to reduce the test current, a method of winding a current-carrying wire around the zero-phase current transformer multiple times is known, but in this case, it is difficult to reduce the size and thickness of the zero-phase current transformer. There was a problem of becoming.

  The present invention has been made in order to solve the above-described problems, and it is possible to reduce the average value of the test current, and it is possible to reduce the size and the thickness of the power circuit section. The purpose is to obtain.

An earth leakage breaker according to the present invention is a zero-phase current transformer having an AC circuit to be detected as a primary winding as a primary winding,
A leakage detection unit for determining whether or not the AC circuit has a leakage according to whether or not the waveform width of the pulsed signal obtained by converting the secondary output of the zero-phase current transformer is equal to or greater than a predetermined value t1, a leakage in the AC circuit A switching element that operates based on the output of the leakage detection unit when a fault occurs, a tripping device that operates based on the operation of the switching element based on the output of the leakage detection unit, and closes the AC circuit in the steady state to A switching circuit for opening the AC circuit by the operation of the disconnecting device, a test circuit for supplying a pulsed simulated leakage current to a test winding wound around the zero-phase current transformer by turning on a test switch ; and A setting unit is provided for changing the operating characteristics of the leakage detection unit during the leakage operation test , and the test switch is turned on to supply a pulsed simulated leakage current to the test winding. Then, the predetermined value is changed to t2 smaller than t1 by the setting unit, and the leakage detecting unit is operated based on the changed predetermined value t2 .

According to the present invention, a zero-phase current transformer having a primary winding as an AC circuit to be detected for leakage current, and a pulse-like signal converted from the secondary output of the zero-phase current transformer has a waveform width of a predetermined value t1 or more. A leakage detection unit that determines whether or not there is a leakage in the AC circuit according to whether there is a leakage, a switching element that operates based on an output of the leakage detection unit when a leakage occurs in the AC circuit, and an output of the leakage detection unit Tripping device that is activated by the operation of the switching element, a test that is wound around the zero-phase current transformer, a switching contact that closes the alternating current circuit and opens the alternating current circuit by the operation of the tripping device in a steady state test circuit for supplying a pulsed simulated ground fault current in the windings by the oN operation of the test switch, and comprising a setting unit for changing the operating characteristics of the earth leakage detection unit at the time of leakage operation test, the test switch When a pulse-like simulated earth leakage current is supplied to the test winding by the ON operation, the predetermined value is changed to t2 smaller than t1 by the setting unit, and the earth leakage is based on the changed predetermined value t2. Since the detection unit operates, the zero-phase current transformer having the primary winding as the AC circuit to be detected for leakage detection, and the waveform width of the pulsed signal converted from the secondary output of the zero-phase current transformer are A leakage detection unit for determining whether or not the AC circuit has a leakage depending on whether or not it is greater than or equal to a predetermined value t1, a switching element that operates based on an output of the leakage detection unit when a leakage occurs in the AC circuit, and the leakage detection A tripping device that is operated by the operation of the switching element based on the output of the unit, a switching contact that closes the AC circuit and opens the AC circuit by the operation of the tripping device in a steady state, and the zero-phase current transformer Winding A test circuit for supplying a pulsed simulated leakage current to the test winding by turning on a test switch, and a zero-phase current transformer based on the pulsed simulated leakage current supplied to the test winding. A test pulse determination unit that activates the switching element in response to a next output, and when the test switch is turned on and a pulse-like simulated leakage current is supplied to the test winding, the predetermined value is determined from t1 Since the test pulse determination unit operates based on the changed predetermined value t2, the peak value of the pseudo signal can be increased without increasing the average value of the pseudo signal during the test. The number of test windings of the zero-phase current transformer can be reduced, the zero-phase current transformer can be reduced in size and thickness, and the power circuit section can be reduced in size and thickness.

It is a block diagram which shows an example of the internal circuit structure of the earth-leakage circuit breaker in Embodiment 1 of this invention. It is explanatory drawing for demonstrating an example of the earth leakage detection operation | movement of the earth leakage circuit breaker in Embodiment 1 of this invention. It is explanatory drawing for demonstrating an example of the earth leakage test operation | movement of the earth leakage circuit breaker in Embodiment 1 of this invention. It is a block diagram which shows the other example of the internal circuit structure of the earth-leakage circuit breaker in Embodiment 2 of this invention. It is explanatory drawing for demonstrating the other example of the earth-leakage detection operation | movement of the earth-leakage circuit breaker in Embodiment 2 of this invention. It is explanatory drawing for demonstrating the other example of the earth leakage test operation | movement of the earth leakage breaker in Embodiment 2 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing an example of the internal circuit configuration of the leakage breaker, FIG. 2 is an explanatory diagram for explaining an example of the leakage detection operation of the leakage breaker shown in FIG. 1, and FIG. 3 is the leakage breaker shown in FIG. It is explanatory drawing for demonstrating the example of the earth leakage test operation | movement of a device.
In FIG. 1, an earth leakage breaker 100 is configured to perform an earth leakage based on a switching contact 2 that opens and closes an AC circuit 1, a zero-phase current transformer 3 that penetrates the AC circuit 1, and a detection signal from the zero-phase current transformer 3. Leakage detection unit 7 to be detected, tripping coil 6a energized via switching element 8 by the output signal of this earth leakage detection unit 7, and pulling that opens / closes contact 2 when this tripping coil 6a is energized A tripping device 6 having a detaching mechanism 6b, and a test device 9 that outputs a predetermined test signal to the zero-phase current transformer and outputs a control signal to the leakage detector 7 by a signal from the test switch 10. A test winding 11 for passing a test signal to the zero-phase current transformer 3, a rectifier circuit 4 for converting an AC voltage input from the AC circuit 1 into a DC voltage, and an output of the rectifier circuit 4 as a predetermined DC Convert to voltage, leakage detector 7 And a constant-voltage circuit 5 for feeding the testing device 9 and the trip device 6.

The leakage detection unit 7 includes an input unit 7a that converts the output current of the zero-phase current transformer 3 into a voltage signal, and a low-pass filter 7b that removes a high-frequency noise signal superimposed on the output signal from the input unit 7a. Are connected to the output of the low-pass filter 7b and are turned on when the output of the low-pass filter 7b is equal to or higher than the threshold value, and connected to the output of the level detection unit 7c. A waveform width detector 7d that is turned on when the time t1 or longer lasts, a trip determination unit 7e that is connected to the output of the waveform width detector 7d and drives the switching element 8 according to the output of the waveform width detector 7d, and a test A switch 7f that short-circuits both ends of the low-pass filter 7b based on the control signal from the device 9 and a predetermined time t1 to the waveform width detector 7d based on the control signal from the test device 9. Detection width setting section is setting unit constant for (hereinafter, referred to as "detection width setting unit") is composed of a 7 g.

  The test device 9 detects that the test switch 10 has been pressed, and is connected to the test input circuit 9a that outputs a control signal to the leakage detection unit 7 and the output of the test input circuit 9a. And a test signal generation circuit 9b for energizing the zero-phase current transformer 3.

Hereinafter, the operation of the leakage detection unit 7 will be described with reference to FIGS. When a leakage occurs and a difference occurs in the current flowing in the AC circuit 1, an output is generated in the zero-phase current transformer 3. The input unit 7 a converts the voltage into a voltage corresponding to the output of the zero-phase current transformer 3. The low-pass filter 7b outputs a signal obtained by removing the harmonic component and extracting the commercial frequency component from the voltage of the input unit 7a. Level detecting unit 7c compares the output of the low pass filter 7 b with a predetermined threshold voltage. If the threshold is positive, there are negative side, the output of the low pass filter 7 b may become more positive side of the threshold, or if the output of the low pass filter 7 b is equal to or less than the negative threshold, Output. The waveform width detection unit 7d monitors the output of the level detection unit 7c, and outputs the output when the output duration lasts for a predetermined time t1 or more. Tripping decision unit 7e counts the number of output from the waveform width detector 7 d, when it reaches the predetermined number of times, and outputs to the switching element 8. The switching element 8 is turned on by its output, an exciting current flows from the constant voltage circuit 5 to the trip coil 6a via the switching element 8, and the trip mechanism 6b operates to open the switching contact 2.

The trip determining unit 7e has a function of determining that the positive side and the negative side are alternated according to the characteristics of the earth leakage breaker, and determining a signal in one direction, for example, positive and positive.
The trip determining unit 7e has a function of resetting the count number when the output of the waveform width detecting unit 7b is not within a predetermined period.

Next, the operation of the test apparatus 9 of this embodiment will be described. The test input circuit 9a determines and outputs that the test switch 10 is closed. The output of the test input circuit 9a is connected to the waveform width detector 7d, thereby changing the predetermined time t1 to t2 (t1 >> t2). The output of the test input circuit 9a is also connected to the LPF bypass unit 7f, and the switch connected in parallel to the LPF is closed to bypass the output of the input unit 7a.

Further, the output of the test input circuit 9a is connected to the trip determination unit 7e, and the function is switched to the function of determining by a one-way signal during the test operation. The test signal generation circuit 9b outputs a pulse signal having a predetermined cycle and a predetermined pulse width (≧ t2) according to the output of the test input circuit 9a. The signal of the test signal generation circuit 9b is converted into a pulse current and applied to the test winding 11, and the zero phase current transformer 3 generates a pulse output corresponding to the signal.

The input unit 7a converts to a pulse voltage corresponding to the pulse output of the zero-phase current transformer 3. Here the low-pass filter 7 b is a signal input portion 7a because it is bypassed by the LPF bypass portion 7f is input to remain level detector 7c of the original waveform. The level detection unit 7c compares with the threshold value and outputs the same as described above. The waveform width detector 7d outputs when the output of the level detector 7c continues for a predetermined time t2 or more. After that, the test operation, that is, the operation capability of the earth leakage breaker is tested by determining and outputting the same as described above and opening the switching contact 2.

  According to the present embodiment, the pseudo signal energized in the zero-phase current transformer 3 has a pulse waveform (pulse-like simulated leakage current). Since the power capacity is greatly reduced, the power capacity (zero phase current transformer 3, test winding 11, etc.) can be reduced in size and thickness. For example, in order to obtain the sine wave output of FIG. 2B, if the effective value of the sine wave current flowing through the test winding 11 is A, the peak value is (√2 × A). When a pulse current having a peak value (√2 × A) and a period T and a pulse width t2 is passed through the test winding 11, the effective value is (√2 × A × √ (t2 / T )) And the power capacity is greatly reduced.

  Further, since the ON duty of the pulse waveform can be shortened by shortening the detection time of the pulse width detection, the peak value of the pseudo signal can be increased without increasing the average value of the signal. Therefore, the number of test windings of the zero-phase current transformer can be reduced, and the zero-phase current transformer can be reduced in size and thickness.

Embodiment 2. FIG.
A second embodiment of the present invention will be described below with reference to FIGS. 4 is a block diagram showing another example of the internal circuit configuration of the leakage breaker, FIG. 5 is an explanatory diagram for explaining an example of the leakage detection operation of the leakage breaker shown in FIG. 4, and FIG. 6 is shown in FIG. It is explanatory drawing for demonstrating the example of the earth leakage test operation | movement of an earth leakage circuit breaker.
In the present embodiment, the leakage detection unit 7 of the first embodiment is changed to the leakage detection unit 7 provided with a test pulse determination unit 17h instead of the switch 7f and the detection width setting unit 7g.

The leakage detection unit 7 includes an input unit 17a that converts the output current of the zero-phase current transformer 3 into a voltage signal, and a low-pass filter 17b that removes a high-frequency noise signal superimposed on the output signal from the input unit 17a. The level detection unit 17c is connected to the output of the low-pass filter 17b and is turned on when the output of the low-pass filter 17b is greater than or equal to the threshold value. The level detection unit 17c is connected to the output of the level detection unit 17c. A waveform width detection unit 17d that is turned on when it lasts for a time t1 or more, a trip determination unit 17e that is connected to the output of the waveform width detection unit 17d and drives the switching element 8 according to the output of the waveform width detection unit 17d, and an input A test pulse discriminating unit 17h that is connected to the output of the unit 17a and operates only when the control signal from the test device 9 is on to drive the switching element 8, It is al configuration.

  The test pulse determination unit 17h is connected to a level detection unit 17h1 that is turned on when the output of the input unit 17a is equal to or greater than a threshold value, and an output of the level detection unit 17h1. A waveform width detection unit 17h2 that is turned on when sustained and a trip determination unit 17h3 that is connected to the output of the waveform width detection unit 17h2 and drives the switching element 8 in accordance with the output of the waveform width detection unit 17h2. Yes. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

Hereinafter, the operation of the leakage detection unit 7 will be described with reference to FIGS. When a leakage occurs and a difference occurs in the current flowing in the AC circuit 1, an output is generated in the zero-phase current transformer 3. The input unit 17 a converts the voltage into a voltage corresponding to the output of the zero-phase current transformer 3. The low-pass filter 17b outputs a signal obtained by removing the harmonic component and extracting the commercial frequency component from the voltage of the input unit 17a. The level detector 17c compares the output of the low pass filter 17b with a predetermined threshold voltage. There are positive and negative threshold values, and the output is performed when the output of the low-pass filter 17b is greater than or equal to the positive threshold value, or when the output of the low-pass filter 17b is less than or equal to the negative threshold value. .

The waveform width detection unit 17d monitors whether the level detection unit 17c outputs or not, and outputs it when the output duration lasts for a predetermined time t1 or more. Tripping determining unit 17e counts the number of output from the waveform width detector 17 d, when it reaches the predetermined number of times, and outputs to the switching element 8. (FIG. 5) The switching element 8 is turned on by its output, the exciting current flows from the constant voltage circuit 5 to the tripping coil 6a via the switching element 8, and the tripping mechanism 6b operates to open the switching contact 2. .

Next, the operation of the test apparatus 9 of this embodiment will be described. The test input circuit 9a determines and outputs that the test switch 10 is closed. The output of the test input circuit 9a is connected to the test pulse determination unit 17h. When the output of the test input circuit 9a is turned on, the test pulse determination unit 17h operates. The trip determining unit 17h3 has a function of determining by a one-way signal.
The test signal generation circuit 9b outputs a pulse signal having a predetermined cycle and a predetermined pulse width (≧ t2) according to the output of the test input circuit 9a. The signal of the test signal generation circuit 9b is converted into a pulse current and applied to the test winding 11, and the zero phase current transformer 3 generates a pulse output corresponding to the signal.

Next, the operation of the test pulse determination unit 17h of the present embodiment will be described. When the test input circuit 9a test switch 10 is closed, the output of the test input circuit 9a is turned on, the test pulse discriminator 17h operates. The level detection unit 17h1 compares the output of the input unit 17a with a predetermined threshold voltage. There are positive and negative threshold values, and the output is made when the output of the input unit 17a is greater than or equal to the positive threshold value, or when the output of the input unit 17a is less than or equal to the negative threshold value. .

  The waveform width detection unit 17h2 monitors whether or not the level detection unit 17h1 outputs, and outputs the output when the output duration lasts for a predetermined time t2 (t1 >> t2). The trip determination unit 17h3 counts the number of outputs from the waveform width detection unit 17h2, and outputs it to the switching element 8 when the predetermined number is reached. (FIG. 5) The switching element 8 is turned on by its output, the exciting current flows from the constant voltage circuit 5 to the tripping coil 6a via the switching element 8, and the tripping mechanism 6b operates to open the switching contact 2. .

  According to the second embodiment, since the pseudo signal energized in the zero-phase current transformer 3 has a pulse waveform (pulse-like simulated leakage current), the average value of the signal compared to a sine wave, rectangular wave, triangular wave, or the like. Therefore, the power capacity is also reduced, and the power circuit unit (zero phase current transformer 3, test winding 11, etc.) can be reduced in size and thickness.

  Further, since the ON duty of the pulse waveform can be shortened by shortening the detection time of the pulse width detection, the peak value of the pseudo signal can be increased without increasing the average value of the signal. Therefore, the number of test windings of the zero-phase current transformer can be reduced, and the zero-phase current transformer can be reduced in size and thickness.

Note that the first embodiment and the second embodiment described above have the following features 1 to 4 from a different viewpoint.
Feature 1: Zero-phase current transformer having a primary winding as the AC circuit to be detected for leakage detection, a leakage detection unit for determining the presence or absence of leakage in the AC circuit based on the secondary output of the zero-phase current transformer, A switching element that operates based on the output of the leakage detection unit when a leakage occurs in the AC circuit, a tripping device that operates by the operation of the switching element based on the output of the leakage detection unit, and the AC circuit in a steady state A simulated earth leakage current for the earth leakage operation test is supplied to the open / close contact that opens and closes the AC circuit by the operation of the tripping device and the test winding wound around the zero-phase current transformer during the earth leakage operation test. It is a ground fault circuit breaker provided with the setting part which changes the operating characteristic of a test apparatus and the said leak detection part at the time of the said leak action test.
Feature 2: In the leakage breaker of Feature 1, the test device supplies a pulsed simulated leakage current to the test winding as the simulated leakage current, and the setting unit sets the operating characteristics of the leakage detection unit, The earth leakage breaker is changed so as to respond to the pulse-like simulated earth leakage current.
Feature 3: Zero-phase current transformer having a primary winding as an AC circuit to be detected for leakage detection, a leakage detection unit for determining the presence or absence of leakage in the AC circuit based on a secondary output of the zero-phase current transformer, A switching element that operates based on the output of the leakage detection unit when a leakage occurs in the AC circuit, a tripping device that operates by the operation of the switching element based on the output of the leakage detection unit, and the AC circuit in a steady state A switching contact that opens and closes the AC circuit by the operation of the tripping device, a test winding wound around the zero-phase current transformer, and a pulse current as a simulated leakage current for a leakage operation test during a leakage operation test A test device for supplying current, and a test pulse determination unit for operating the switching element in response to a secondary output of the zero-phase current transformer based on the pulsed current supplied to the test winding A fault interrupter having.
Feature 4: A switching contact installed in the AC circuit, a zero-phase current transformer that uses the AC circuit as a primary winding, and whether or not the AC circuit is leaked is determined from the secondary output of the zero-phase current transformer. A leakage detection unit that outputs a signal when a leakage occurs, a tripping device provided to trip the switching contact based on an output signal of the leakage detection unit, and the tripping device connected in series A test for supplying a simulated leakage current to a switching element (switching element, switching means) that operates the tripping device according to the conduction and a test winding wound around the zero-phase current transformer by turning on a test switch. Circuit (test device), the ON duty of the simulated leakage current is a small duty that cannot be detected by the leakage detection circuit when the test switch is not turned on. And then, the at the time of ON operation of the test switch, a circuit breaker wherein the leakage detecting circuit changes the detectable sensitivity of the simulated ground fault current.

In the present invention, each embodiment can be appropriately modified or omitted within the scope of the invention.
In addition, in each figure, the same code | symbol shows the same or an equivalent part.

2 switching contacts, 3 zero-phase current transformer, 6 trip device,
7 leakage detector, 7g setting unit, 8 switching element,
9 test circuit ( test equipment ) , 10 test switch, 11 test winding,
100 Earth leakage breaker.

Claims (2)

A zero-phase current transformer whose primary winding is the AC circuit to be detected for leakage,
A leakage detection unit that determines whether or not the AC circuit has a leakage depending on whether the waveform width of the pulse-like signal obtained by converting the secondary output of the zero-phase current transformer is equal to or greater than a predetermined value t1 ;
A switching element that operates based on the output of the leakage detection unit when leakage occurs in the AC circuit,
A tripping device that operates by the operation of the switching element based on the output of the leakage detection unit;
Open and close contacts that normally close the AC circuit and open the AC circuit by the operation of the trip device,
A test circuit for supplying a pulsed simulated leakage current to a test winding wound around the zero-phase current transformer by turning on a test switch , and a setting unit for changing the operating characteristics of the leakage detection unit during a leakage operation test equipped with a,
When the test switch is turned on and a pulse-like simulated leakage current is supplied to the test winding, the setting unit changes the predetermined value to t2, which is smaller than the t1, and changes to the changed predetermined value t2. The leakage detection unit operates based on
An earth leakage circuit breaker characterized by that. A zero-phase current transformer whose primary winding is the AC circuit to be detected for leakage,
A leakage detection unit that determines whether or not the AC circuit has a leakage depending on whether the waveform width of the pulse-like signal obtained by converting the secondary output of the zero-phase current transformer is equal to or greater than a predetermined value t1;
A switching element that operates based on the output of the leakage detection unit when leakage occurs in the AC circuit,
A tripping device that operates by the operation of the switching element based on the output of the leakage detection unit;
Open and close contacts that normally close the AC circuit and open the AC circuit by the operation of the trip device,
A test circuit for supplying a pulsed simulated leakage current to a test winding wound around the zero-phase current transformer by turning on a test switch; and
A test pulse determination unit that operates the switching element in response to the secondary output of the zero-phase current transformer based on the pulse-like simulated leakage current supplied to the test winding
With
When the test switch is turned on and a pulsed simulated leakage current is supplied to the test winding, the predetermined value is changed to t2 smaller than t1, and the test pulse is changed based on the changed predetermined value t2. An earth leakage circuit breaker characterized in that the determination unit operates .

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