JP4631419B2 - Earth leakage breaker operation cause analyzer - Google Patents

Description

  The present invention relates to an earth leakage breaker operation cause analysis device that analyzes and determines a cause when an earth leakage breaker incorporated in a distribution board performs an interruption operation.

  The earth leakage circuit breaker is an effective safety device for preventing electric shock disasters and fires, and prevents accidents by immediately shutting off the power supply when an earth leakage occurs. In addition to earth leakage and ground fault protection, the earth leakage circuit breaker has an overcurrent protection function that protects against overload and short circuit, and also performs neutral wire phase loss protection with a single-phase three-wire circuit. Some with phase-opening protection. For this reason, when the earth leakage circuit breaker operates, it is necessary to accurately determine the cause of the operation based on the situation and restore the power failure.

FIG. 23 shows a flowchart as an example of a procedure for investigating the cause when the earth leakage circuit breaker performs a breaking operation, and will be described.
In step S0, it is assumed that the earth leakage circuit breaker is in an operating state. In step S1, it is determined whether or not there is a leakage indication of the leakage breaker (ELCB). If there is, in step S2, the electrical equipment is checked by visual inspection or the like, and if there is no abnormality, the earth leakage breaker is turned on.

  In step S3, it is determined whether or not the earth leakage breaker has been turned on. If it cannot be turned on, that is, if it trips, the load side switch of the earth leakage breaker is opened and turned on again in step S4. In step S5, it is determined whether or not the recharging has been performed. If it can be turned on, the load side switch is turned on sequentially in step S6. If the earth leakage circuit breaker operates in this process, it can be estimated that there is a defective portion in the circuit after that, that is, the circuit after the corresponding load side switch.

Therefore, in step S7, it can be estimated that there is a possibility of temporary insulation failure or unnecessary operation. Therefore, an insulation failure test of equipment is performed, and if there is no problem as a result, a waveform is recorded and the cause is investigated. The process in step S7 is also performed when the input can be made in step S3.
In step S1, if there is no leakage display, it can be estimated in step S8 that there is a possibility of an overload, a short circuit, or a phase failure. For this reason, in step S9, it is determined whether or not there is an arc trace of each switch, circuit, or the like. If there is, the defective portion is repaired in step S10. In step S11, the earth leakage breaker is turned on and the state is observed for a while.

On the other hand, if it is determined in step S9 that there is no load, the load side switch and the hand switch of the electric device are opened in step S12. In step S13, the earth leakage circuit breaker is turned on, and the cause is investigated while turning on the opened switches. Investigate the cause by recording the waveform if necessary.
Further, in the above-described step S5, when it cannot be turned on, in step S14, it is turned on after removing the load side wiring of the earth leakage breaker, and it is determined whether or not the turning-on has been made. If it has been successfully turned on, it can be estimated in step S15 that there is an insulation failure between the earth leakage breaker and the load side switch. On the other hand, when it was not able to be thrown in, it can be estimated in step S16 that the earth leakage breaker (ELCB) is a failure.

  By the way, the earth leakage circuit breaker operates to cut off against electric leakage, ground faults, etc. as described above, but also a surge (for example, a lightning surge or an open / close surge due to turning on / off of load equipment) or a high frequency generated by an inverter device. An unnecessary operation (also referred to as annoying operation) may occur due to the leakage current. If the earth leakage circuit breaker is interrupted due to temporary insulation failure or phase failure, or if it operates unnecessarily as described above, it is very difficult to investigate the cause, and it takes a long time to determine the cause. In some cases.

In such a case, the cause is investigated using various measuring instruments such as a waveform recorder as in Patent Document 1 and a leakage detector as in Patent Document 2.
The waveform recorder of Patent Document 1 records the load current, voltage, and leakage current when the earth leakage circuit breaker operates, and displays the waveform data display of each recorded electrical quantity, and each electric current calculated based on the waveform data. By comparing the effective value of various quantities with the rated value of the earth leakage breaker, it is determined whether the cause of the breaking operation of the earth leakage breaker is due to leakage, overload, or phase loss.

In addition, the leakage detector of Patent Document 2 includes a leakage detection circuit and an open-phase detection circuit, and can determine whether the cause of the breaking operation of the leakage breaker is leakage or open-phase.
Japanese Patent Laid-Open No. 5-264295 JP 2001-235503 A

By the way, in the case where the earth leakage circuit breaker is interrupted due to temporary insulation failure or phase failure, the cause can be investigated by installing a waveform recorder or an earth leakage detector for a long time.
However, when the earth leakage circuit breaker operates unnecessarily due to the surge or the high-frequency leakage current generated by the inverter as described above, the cause is often unknown by simple waveform observation, evaluation by effective value calculation, or an earth leakage detector. .

This will be described using, for example, the inverter installation circuit shown in FIG.
The inverter 101 generates a large number of high-frequency components when the rectifier circuit 102 converts AC power into DC by rectification, and then switches to AC by the semiconductor element circuit 103, and this high-frequency component exists in the electric circuit. Since the capacitor C1 always flows, the high-frequency leakage current I1 increases as the ground capacitance C1 increases. The earth leakage breaker 105 may operate unnecessary due to the high-frequency leakage current I1.

Further, when a ground fault occurs in a circuit in which the high-frequency leakage current I1 is constantly generated, a ground fault may not be detected in waveform observation. For example, FIG. 25 shows a leakage current waveform when a ground fault occurs at point P1 in FIG. 24 (on the power supply side from the inverter 101).
In the waveform of FIG. 25, the ground-fault current component of the commercial frequency is buried in the high-frequency leakage current I1, and it becomes difficult to determine a ground fault by just observing the waveform. In addition, at first glance at the waveform in FIG. 25, there is a possibility that the breaking operation of the leakage breaker 105 is erroneously determined as an unnecessary operation due to the high-frequency leakage current I1 of the inverter 101.

In addition, when a ground fault occurs at point P2 (load side from the inverter 101) in FIG. 24, a high-frequency ground fault current may be generated depending on the operating frequency of the inverter 101. In this case, the conventional effective value is obtained. Evaluation by calculation also becomes difficult.
In such a case, frequency analysis of leakage current may be performed by Fourier transform, but in Fourier transform, a signal in a certain time range is periodically continuous from infinite past to infinite future. Therefore, it is an effective method for a stationary signal whose signal is continuously stable, but sufficient analysis cannot be performed for an unsteady signal such as a transient phenomenon.

In addition, when the leakage detector 105 described above is reached, it is basically possible to determine whether or not there is a leakage, and it is not possible to investigate the cause of the unnecessary operation.
In addition, depending on the frequency characteristics of the leakage detector 105, there is a possibility of a hypersensitive reaction to the surge or the high-frequency leakage current I1 caused by the inverter 101. In this case, there is a possibility that the leakage is erroneously determined. On the contrary, depending on the frequency characteristics of the leakage detector 105, there is a possibility that the high-frequency ground fault current as described above cannot be detected.

  The present invention has been made in view of such problems, and can determine whether the earth leakage breaker has normally operated due to earth leakage or whether it has a sensitive operation (unnecessary operation) due to high-frequency leakage current from a surge or an inverter. An object of the present invention is to provide a circuit breaker operation cause analysis device.

To achieve the above object, electric leakage circuit breaker operation cause analysis apparatus of the present invention, detection and line voltage between line fault interrupter is connected, the load current, and leakage current is zero-phase current In the earth leakage circuit breaker operation cause analyzer for analyzing the cause of the operation of the earth leakage breaker by recording the waveform data of these detected electric quantities for several cycles before and after the operation of breaking the earth leakage breaker, the earth leakage breaker The operation judgment level of the leakage current that operates is set , and the rated inoperative current of the leakage breaker is set to a frequency coefficient that is a ratio of the threshold value of the ventricular fibrillation with respect to the alternating current with respect to the commercial frequency. setting means for setting a multiplication value as a first judgment level, by the recorded leakage current time-frequency analysis, analysis means for obtaining a temporal variation of the frequency spectrum of the leakage current, the A first determination level is compared with the frequency spectrum of the leakage current, and determining discrimination means an operation causes the earth leakage breaker and leakage when the frequency components above to the leakage current the first determination level is present It is provided with.
According to this configuration, it is possible to determine whether the earth leakage circuit breaker has normally operated due to earth leakage or whether it has a sensitive operation (unnecessary operation) due to other causes.
The setting means sets one of a rated sensitivity current and a rated inoperative current of the earth leakage breaker as a second determination level, and the determining means determines that the cause of the operation of the earth leakage breaker is an earth leakage. If not, the second determination level is compared with the frequency spectrum, and if a frequency component exceeding the second determination level is continuously generated, an unnecessary operation due to high-frequency leakage current by the inverter device In the case where a frequency component exceeding the second determination level is generated for a very short time, it is determined that the operation is unnecessary due to the surge.

According to this configuration, it is possible to determine whether the earth leakage circuit breaker has normally operated due to the earth leakage, or whether it has a sensitive operation (unnecessary operation) due to other causes . and unnecessary operation due to high-frequency leakage current by the inverter device, Ru can be accurately determined which of unnecessary operation due to surge.
The front SL analyzing means, characterized by using short-time Fourier transform on the time-frequency analysis.
According to this configuration, since the short-time Fourier transform always keeps the window width of the window function W constant regardless of the frequency, it is compared with the continuous wavelet transform for continuous high-frequency leakage current generated by an inverter. Therefore, the magnitude of the leakage current can be obtained quantitatively such as a three-dimensional expression based on this feature.

The front SL analyzing means, characterized by using the continuous wavelet transform on the time-frequency analysis.
According to this configuration, the wavelet equivalent to the window function can be made variable according to the frequency by the scale parameter in the continuous wavelet transform. It has a characteristic with excellent resolution, and based on this characteristic, the magnitude of the leakage current can be obtained so that it can be quantitatively understood, such as a three-dimensional expression.

  As described above, according to the present invention, there is an effect that it is possible to determine whether the earth leakage circuit breaker has normally operated due to earth leakage or whether it has a sensitive operation (unnecessary operation) due to a high-frequency leakage current from a surge or an inverter.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an earth leakage circuit breaker operation cause analyzer according to an embodiment of the present invention.
1 is a voltage sensor 4 that measures the line voltage on the load side (connection side of the distribution breaker 3) of the leakage breaker 2 disposed in the distribution board 1. , Current sensor 5 for measuring load current, current sensor 6 for measuring leakage current (zero-phase current), waveform data of line voltage, load current and leakage current for several cycles before and after the breaking operation of leakage breaker 2 A waveform recording unit 7 for storing the current, a time frequency analyzing unit (analyzing means) 8 for analyzing the recorded leakage current waveform by a short time Fourier transform or continuous wavelet transform, and a leakage breaker 2 Analyze and determine the cause of the breaker operation of the earth leakage breaker 2 from the comparison of the operation frequency level analysis result and the operation determination level of the operation determination level setting unit (setting means) 9 for setting the operation determination level of the leakage current (Distinction) Operation cause analyzer (the determination means) 10 is configured by a display unit 11 for displaying the analysis and determination result.

The operation of the operation cause analysis of the earth leakage breaker by the earth leakage circuit breaker operation cause analysis device having such a configuration will be described.
First, waveform data of various electrical quantities (line voltage, load current, leakage current) for several cycles before and after the voltage loss is triggered by the loss of power supply voltage triggered by the circuit breaker 2 breaking operation. Record in part 7. Next, the temporal change in the frequency component of the recorded leakage current (zero phase current) is analyzed by the time frequency analysis unit 8. Here, the time frequency analysis of the leakage current is performed by short-time Fourier transform or continuous wavelet transform.

As shown in FIG. 2, in the short-time Fourier transform, the frequency spectrum F (b, ω) of a signal obtained by cutting out the time function f (t) using the window function W (t−b) centered on the time b is used. The time b is a parameter, and the temporal change of the frequency component of the time function f (t) is captured by obtaining the frequency spectrum F (b, ω) while changing the window position (time b). Can do.
Here, the short-time Fourier transform of the time function f (t) is expressed by the following equation (1).

  Various functions have been proposed for the window function of Expression (1). In the present invention, the Hanning window of the following Expression (2) is used.

Where a: window width (constant)
The continuous wavelet transform is one of the time frequency analysis methods similar to the short-time Fourier transform, and the continuous wavelet transform of the time function f (t) is expressed by the following equation (3).

However,
Ψ: Mother wavelet a: Scale parameter (1 / a corresponds to frequency)
b: Translation (shift) parameter In addition, the part with a bar on Ψ (t) is the conjugate of Ψ (t) Ψ in Equation (3) is called an analyzing wavelet (or simply called a wavelet) Similar to the window function W, various functions have been proposed. In the present invention, the Gabor complex wavelet {the following formula (4)}, which is said to be most localized in the time frequency change, is used. FIG. 3 shows only the real part of the Gabor complex wavelet of equation (4).

However, σ = 8
Here, Ψ (t) in equation (4) is replaced with Ψ ((t−b) / a). a is referred to as a scale parameter, b is referred to as a translation (shift) parameter, the scale parameter a causes the wavelet Ψ (t) to expand or contract in the time axis direction (1 / a corresponds to the frequency), and the translation parameter b As shown in FIG. 4, the wavelet Ψ (t) can be translated in the time axis direction.

  The wavelet Ψ {(t−b) / a} in the equation (3) corresponds to the window function W referred to in the short-time Fourier transform, and the window width can be appropriately selected by the scale parameter a. That is, the time window can be made small for the high frequency component of the signal to be analyzed, and conversely, the time window can be made large for the low frequency component. In other words, in the short-time Fourier transform, the width of the time window is fixed in the sense that it does not change with respect to the frequency, whereas in the continuous wavelet transform, there is flexibility according to the frequency, and the time window is automatically Is narrow at high frequencies and wide at low frequencies.

Next, an example of time frequency analysis of a leakage current waveform will be described.
5 and 6 show the results of short-time Fourier transform and continuous wavelet transform of the leakage current waveform. The upper part (a) of FIGS. 5 and 6 shows a leakage current waveform, which is a leakage current waveform (FIG. 3) when a ground fault occurs at point a in the inverter installation circuit of FIG. The middle stage (b) and the lower stage (c) are the results of short-time Fourier transform {Equation (1)} or continuous wavelet transformation {Equation (3)} with the leakage current as a time function f (t). The magnitude of the leakage current is shown by time and frequency.

In the gray scale diagram in the middle part (b) of FIG. 5 and FIG. 6, the horizontal axis is time, the vertical axis is frequency (indicated by the order n with the commercial frequency (50 Hz) as the fundamental frequency), and the components with larger amplitude are brighter. Show. When this is expressed in three dimensions, it becomes the lower stage (c) of FIG. 5 and FIG. 6, and the size can be understood quantitatively.
5 and 6, the 60th-order (3 kHz) vicinity component increases continuously over time. This is a high-frequency leakage current generated by the inverter, and a frequency component just equal to the carrier frequency (3 kHz) of the inverter is generated. Further, the component near the commercial frequency is rapidly increased from around 1250 × 80 μs. This indicates that a ground fault current at a commercial frequency is generated due to the ground fault.

3 or FIG. 5 and FIG. 6 in the upper part (a) of the leakage current waveform, it is difficult to determine that a ground fault has occurred, but in the middle part (b) and lower part (c) of FIG. 5 and FIG. As described above, when the magnitude of the leakage current is observed from both the time and frequency sides, it can be determined that the ground fault current of the commercial frequency component is generated.
Next, the operation determination level of the leakage current is set by the operation determination level setting unit 9 so that the leakage breaker 2 operates, and the operation determination analysis is performed on the set operation determination level and the result obtained by the time frequency analysis unit 8. Used in the unit 10 to analyze and determine the cause of the breakage of the earth leakage breaker 2.

  Two determination levels are set as the operation determination level. Among these, the first determination level (hereinafter referred to as determination level L1) is described in “IEC (International Electrotechnical Commission) 479-2 (Effects of current passing through the human body. Part 2: Special aspects)”. The threshold value of ventricular fibrillation for alternating current at frequencies other than the commercial frequency is a frequency coefficient (FIG. 7) shown with reference to the commercial frequency (50/60 Hz). The value multiplied by is used.

FIG. 7 shows the threshold value of ventricular fibrillation with respect to the alternating current in a ratio based on the commercial frequency (50/60 Hz). If this ratio (coefficient) exceeds 1, the risk is reduced. Means. In FIG. 7, when the frequency is higher than the commercial frequency (50/60 Hz), the threshold value for ventricular fibrillation also increases.
The earth leakage breaker disclosed in Japanese Patent Laid-Open No. 10-42457 has a frequency characteristic of the sensitivity current considering the characteristics of FIG. 7 for the purpose of protecting the human body in the high frequency region and avoiding unnecessary operations.

By the way, in “JIS C 8371 Earth Leakage Breaker”, the sensitivity current of the earth leakage breaker (the zero-phase current that causes the earth leakage breaker to break) is specified to exceed the value of the rated inoperative current and below the value of the rated sensitivity current. is doing.
Therefore, the curve obtained by multiplying the frequency coefficient in FIG. 7 by the rated inoperative current of the earth leakage breaker should be used as one guideline for judging the breaking operation due to earth leakage (normal operation) and the unnecessary operation due to high frequency leakage current. Can do.

  That is, a curve obtained by multiplying the frequency coefficient of FIG. 7 by the rated inoperative current value of the earth leakage breaker is set as a first operation determination level (determination level L1), and the frequency spectrum of each time section of the determination level L1 and the leakage current If there is a frequency component that exceeds the determination level L1, it is determined that the circuit is cut off due to electric leakage (normal operation). If no frequency component that exceeds the determination level L1 is included, an unnecessary operation is performed. It can be judged.

FIG. 8 shows characteristics of the determination level L1 when the rated inoperative current value of the earth leakage breaker 2 is 15 mA. Note that the rated inoperative current is described in the earth leakage breaker 2. Further, as shown in FIG. 7, IEC479-2 describes only up to 1 kHz as a threshold value for ventricular fibrillation. For this reason, a frequency coefficient exceeding 1 kHz is obtained by extrapolation.
FIGS. 9 and 10 show the results of extracting a portion exceeding the determination level L1 (FIG. 8) from the frequency spectrum of FIGS. Compared with FIGS. 5 and 6, the high-frequency leakage current is filtered, and only the ground fault current component is extracted. In the results of FIGS. 9 and 10, the cause of the interruption is determined to be the interruption operation due to electric leakage.

  Next, when it is not determined that there is a leakage due to comparison with the determination level L1, it is checked whether the breaking operation of the leakage breaker 2 is an unnecessary operation due to a high-frequency leakage current caused by a surge or an inverter. Here, as the second operation determination level (hereinafter referred to as determination level L2), the rated moving current or rated inoperative current of the earth leakage breaker 2 is set, and the comparison is made with the frequency spectrum of the leakage current to determine the surge current. Whether or not the operation was unnecessary due to high-frequency leakage current from the inverter. The determination level L2 is constant for all frequency regions.

  FIG. 11 shows an example of a leakage current waveform when the leakage breaker 2 is unnecessarily operated due to the high-frequency leakage current of the inverter, and the result of the short-time Fourier transform. FIG. 12 shows the result of extracting only frequency components exceeding the determination level L1 from the result of FIG. In FIG. 12, there is no frequency component exceeding the determination level L1, and in this case, the breaking operation of the leakage breaker 2 is determined as an unnecessary operation. In FIG. 12, the rated inoperative current value of the determination level L1 is 15 mA.

  Next, FIG. 13 shows a result of extracting only frequency components exceeding the determination level L2 from the result of FIG. In FIG. 13, the determination level L2 is set to a rated inoperative current value of 15 mA. This setting is the same for the subsequent determination level L2. It can be seen from FIG. 13 that frequency components exceeding the determination level L2 appear continuously in the 60th order (3 kHz).

  Similarly, FIG. 14 shows the result of continuous wavelet transform of the leakage current waveform of FIG. Further, FIG. 15 shows a result of extracting only frequency components exceeding the determination level L1 from the result of FIG. Similar to the result of the short-time Fourier transform, in this case, the breaking operation of the earth leakage breaker 2 is determined as an unnecessary operation. Further, FIG. 16 shows a result of extracting frequency components exceeding the determination level L2 from the result of FIG. After all, similarly to the result of the short-time Fourier transform, a region exceeding the determination level L2 appears continuously in the vicinity of the 60th order (3 kHz). In FIG. 16 as well, the determination level L2 is set to a rated inoperative current value of 15 mA.

  Next, FIG. 17 shows an example of a leakage current waveform when the earth leakage circuit breaker 2 performs an unnecessary operation due to a high-frequency leakage current due to a switching surge and a result of the short-time Fourier transform. Further, when a frequency component exceeding the determination level L1 is extracted from the result of FIG. 17, the result is as shown in FIG. 18. In this case, there is no frequency component exceeding the determination level L1, and the circuit breaker 2 is determined to be an unnecessary operation. The Further, when a frequency component exceeding the determination level L2 is extracted from the result of FIG. 17, the result is as shown in FIG.

  Similarly, when the leakage current waveform of FIG. 17 is subjected to continuous wavelet transform, the result is as shown in FIG. Furthermore, when a frequency component exceeding the determination level L1 is extracted from FIG. 20, the result is as shown in FIG. 21, and in this case, there is no frequency component exceeding the determination level L1, and the interruption operation of the earth leakage breaker is determined as an unnecessary operation. Further, when a frequency component exceeding the determination level L2 is extracted from the result of FIG. 17, the result is as shown in FIG.

Referring to FIGS. 19 and 22, in an impulse high-frequency leakage current generated by a surge, a region exceeding the determination level L <b> 2 occurs in a relatively wide frequency region even though it is extremely short in time.
As described above, when a frequency component exceeding the determination level L2 exists in a relatively high frequency band, it is determined that the operation is unnecessary due to the high-frequency leakage current, and further, the frequency component exceeding the determination level L2 appears continuously in time. If the frequency component exceeds the determination level L2 in a relatively wide frequency range for an extremely short time, it is determined that the operation is unnecessary due to surge. Is determined.

  This determination will be further described with reference to FIGS. These figures are image diagrams when a portion exceeding the determination level L2 is extracted from the result of short-time Fourier transform or continuous wavelet transform, FIG. 26 is an image diagram when an unnecessary operation is performed by a surge, and FIG. 27 is an inverter device. It is an image figure when unnecessary operation | movement is carried out by the high frequency leakage current. Further, in each figure, the portion exceeding the determination level L2 is indicated by “1”, and the others are indicated by “0” (shown by blanks in the figure).

  The result of the short-time Fourier transform or continuous wavelet transform is expressed by an m × n array {m: sample number, n: frequency (order)}, of which “1” is the portion exceeding the judgment level L2, and the others Is converted to “0”. This result is searched in the time axis and frequency axis directions, and as shown in FIG. 27, when there is a portion where “1” is continuously present in the high frequency component, it is determined that the inverter device is not required to operate due to the high frequency leakage current. To do. Further, as shown in FIG. 26, when there is a portion exceeding “1” in a wide frequency band in a short time, it is determined that the operation is unnecessary due to the surge.

The result display unit 11 displays these determination results and the frequency spectrum of the leakage current as shown in FIGS.
When the results of the short-time Fourier transform and the continuous wavelet transform are compared, it can be seen that the shape or size of the frequency spectrum is slightly different. In the short-time Fourier transform, the window width of the window function W is always constant regardless of the frequency, so that the frequency resolution is superior to the continuous wavelet transform for continuous high-frequency leakage current generated by an inverter. Yes.
On the other hand, in the continuous wavelet transform, the wavelet Ψ corresponding to the window function W can be made variable according to the frequency by the scale parameter a. Therefore, the time resolution is smaller than the short-time Fourier transform for a local phenomenon such as a surge. Has excellent characteristics.

  As described above, according to the leakage breaker operation cause analysis device of the present embodiment, the time frequency analysis unit 8 performs frequency analysis on the leakage current (zero-phase current) during the breaking operation of the leakage breaker 2, By analyzing the temporal change of the frequency component, the transient leakage current change at the time of the breaking operation of the earth leakage breaker 2 is grasped from both the time and the frequency, and the operation cause analysis unit 10 describes IEC479-2. By evaluating the leakage current in consideration of the threshold of ventricular fibrillation with respect to the frequency of the leakage current, the operation of the leakage breaker 2 has operated normally due to leakage, or has been sensitive (unnecessary operation) due to high-frequency leakage current due to surge or inverter It has an excellent effect of being able to analyze and discriminate.

It is a figure which shows the structure of the earth-leakage circuit breaker operation | movement cause analysis apparatus using the apparatus which concerns on embodiment of this invention. It is an image figure of short-time Fourier transform. It is a figure which shows the real part of a Gabor (Gabor) complex wavelet. It is a figure for demonstrating the shift scale conversion of a wavelet. It is a figure which shows the example of the short-time Fourier transform of a leakage current waveform. It is a figure which shows the example of the continuous wavelet transformation of a leakage current waveform. It is a figure which shows the frequency coefficient which represented the threshold value of the ventricular fibrillation with respect to the frequency in IEC479-2 on the basis of 50 / 60Hz. It is a figure which shows the 1st operation | movement determination level when the rated inoperative current of an earth-leakage circuit breaker is 15 mA. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 1 with respect to FIG. It is a figure which shows the result of having extracted only the frequency component which exceeds the operation | movement determination level 1 with respect to FIG. It is a figure which shows the example of short-time Fourier-transform of the leakage current waveform at the time of the earth leakage circuit breaker unnecessary operation | movement by the high frequency leakage current of an inverter. It is a figure which shows the result of having extracted only the frequency component which exceeds the operation | movement determination level 1 with respect to FIG. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 2 with respect to FIG. It is a figure which shows the example of continuous Fourier transformation of the leakage current waveform at the time of the earth leakage circuit breaker unnecessary operation | movement by the high frequency leakage current of an inverter. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 1 with respect to FIG. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 2 with respect to FIG. It is a figure which shows the example of short-time Fourier transform of the leakage current waveform at the time of the earth leakage circuit breaker unnecessary operation | movement by the high frequency leakage current by switching surge. It is a figure which shows the result of having extracted only the frequency component which exceeds the operation | movement determination level 1 with respect to FIG. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 2 with respect to FIG. It is a figure which shows the example of continuous wavelet conversion of the leakage current waveform at the time of the earth-leakage circuit breaker unnecessary operation | movement by the high frequency leakage current by switching surge. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 1 with respect to FIG. It is a figure which shows the result of having extracted only the frequency component exceeding the operation | movement determination level 2 with respect to FIG. It is a flowchart of the example of investigation procedure of interruption | blocking operation | movement cause of an earth-leakage circuit breaker. It is a figure which shows the example of an inverter installation circuit. It is a figure which shows the example of a leakage current waveform when a ground fault generate | occur | produces in an inverter installation circuit. It is an image figure when an earth-leakage circuit breaker carries out unnecessary operation | movement by the surge. It is an image figure when an earth-leakage circuit breaker carries out unnecessary operation | movement by the high frequency leakage current of an inverter apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Distribution board 2 Earth leakage breaker 3 Distribution breaker 4 Voltage sensor 5 Current sensor 6 Current sensor 7 Waveform recording part 8 Time frequency analysis part 9 Operation judgment level setting part 10 Operation cause analysis part 11 Display part

Claims (4)

Detects line voltage, load current, and leakage current that is zero-phase current between the lines connected to the earth leakage breaker, and detects the waveform data of these detected electrical quantities before and after breaking operation of the earth leakage breaker. In the earth leakage circuit breaker operation cause analysis device that records several cycles and analyzes the cause of the operation of the earth leakage breaker,
The operation judgment level of the leakage current at which the earth leakage breaker operates is set , and the rating of the earth leakage breaker is set to a frequency coefficient indicated by a ratio of a ventricular fibrillation with respect to an alternating current with respect to a commercial frequency. Setting means for setting a value obtained by multiplying the non-operating current as the first determination level ;
Analyzing means for obtaining a temporal change in the frequency spectrum of the leakage current by performing time frequency analysis of the recorded leakage current;
Comparing the frequency spectrum of the first decision level and the leakage current, determined determines operation cause of the earth leakage breaker and leakage when the frequency component is present in excess to the leakage current the first determination level An earth leakage circuit breaker operation cause analysis device characterized by comprising:   The setting means sets one of a rated sensitivity current and a rated inoperative current of the leakage breaker as a second determination level,
  The determination means compares the second determination level with the frequency spectrum when the cause of the operation of the leakage breaker is not determined to be leakage, and a frequency component exceeding the second determination level is continuously generated. If the frequency component exceeds the second determination level for a very short time, it is determined as an unnecessary operation associated with the surge.
  The ground fault circuit breaker operation cause analysis device according to claim 1. It said analysis means, earth leakage breaker operates due analyzer according to claim 1 or 2, characterized in that a short-time Fourier transform on the time-frequency analysis. The ground fault circuit breaker operation cause analysis device according to claim 1 or 2 , wherein the analysis means uses continuous wavelet transform for the time-frequency analysis.