JP6746197B2 - Tracking phenomenon detection system - Google Patents

Description

The present invention relates to means capable of detecting a discharge accident in an electric circuit.

Conventionally, means for detecting a discharge accident in an electric circuit have been studied. For example, Patent Document 1 proposes a means for interrupting the electric path when a light emission phenomenon caused by spark discharge is detected. Moreover, a method of detecting the occurrence of an accident by frequency analysis of noise superimposed on a commercial power source has been proposed.

JP, 10-106686, A

By the way, the technique described in Patent Document 1 adopts a structure in which a light emitting phenomenon occurring outside the product is detected by a light emitting element arranged inside the product. Therefore, if the technique described in Patent Document 1 is adopted, it is necessary to make a hole in the product. Further, in the method of detecting the occurrence of an accident by frequency-analyzing the noise superimposed on the commercial power source, it is difficult to observe the waveform when the noise is small.

An object of the present invention, which has been made in view of such circumstances, is to make it possible to detect the occurrence of an electric discharge accident without drilling a product. Further, it is to make it possible to detect even a small amount of noise caused by a discharge accident.

In order to solve the above problems, the following means are adopted. The first means is a discharge accident detection system including a measuring route in which a capacitor and a portion to be measured are arranged in series between different poles of an electric path, and a measuring means for measuring the portion to be measured is provided.

Further, the second means is preferable in that the first means is provided with a judging means for judging a discharge accident based on the measurement result of the measuring means.

Also, in the second means, the detection route is a CR circuit in which a capacitor and a resistor are connected in series, and the measuring means is arranged so as to measure the voltage value applied to both ends of the resistor to prevent a discharge accident. It is preferable to use the third means configured to measure the high frequency noise generated by.

In the third means, the fourth means is preferably the fourth means configured to determine that there is a discharge accident when the measured voltage value exceeds a threshold value.

Further, in the third or fourth means, the determining means is configured to determine that there is a discharge accident when the number of occurrences of high frequency noise measured by the measuring means per constant time exceeds a set value. The fifth means described above is preferred.

Further, in any one of the third to fifth means, a plurality of CR circuits are provided between different poles of the electric path, and the determination means compares the measurement results of the measured portions of each CR circuit and discharges. The sixth means which is configured to determine the presence or absence of an accident is preferable.

Further, in the sixth means, the seventh means is preferable, in which at least one CR circuit includes a capacitor having a frequency characteristic different from that of a capacitor included in another CR circuit.

In the first means, since it is not necessary to detect the light emission phenomenon by the light receiving element, it is not necessary to make a hole in the product. Further, since the part to be measured and the capacitor are arranged in series between the different poles of the electric path, it may be possible to detect even if the noise is relatively small. Further, the discharge accident can be detected even when the position where the discharge accident occurs and the detection route are distant from each other.

In the second means, the determination means makes the determination based on the detection result, so that the determination based on the detection result becomes easy.

The third means employs a CR circuit. Therefore, a high frequency can be detected, and even if noise due to a discharge accident is relatively small, it can be detected.

The fourth means determines that there is a discharge accident when the measured voltage value exceeds a threshold value. Therefore, it is possible to make the structure of the determination means relatively simple.

The fifth means determines that there is a discharge accident when the number of times high-frequency noise generated by the measuring means per fixed time exceeds a set value. Therefore, it is possible to distinguish between the switching noise generated when the power of the device is turned on and the noise generated when the tracking phenomenon or the like occurs.

In the sixth means, a plurality of CR circuits are provided between different poles of the electric path. Further, the judging means judges the presence or absence of a discharge accident by comparing the measurement results of the measured parts of the CR circuits. Therefore, it is possible to improve the detection accuracy.

In the seventh means, a plurality of CR circuits are provided between different poles of the electric path, and at least one CR circuit is provided with a capacitor having a frequency characteristic different from that of a capacitor provided in another CR circuit. Further, the judgment means judges the presence or absence of a discharge accident by comparing the measurement results of the measured parts of the respective CR circuits. Therefore, it is possible to detect noise in different frequency bands, and it is possible to improve detection accuracy.

It is a schematic diagram of a first embodiment. It is a conceptual diagram when tracking occurs in the first embodiment. It is an example of the voltage waveform measured by the measuring means in the state where tracking does not occur. It is an example of the voltage waveform measured by the measuring means in the state where tracking is occurring. It is a schematic diagram of a second embodiment.

Modes for carrying out the invention are shown below. FIG. 1 is a schematic diagram of the first embodiment. FIG. 2 is a conceptual diagram when a discharge accident such as tracking occurs in the first embodiment. As shown in FIG. 1, in the discharge accident detection system 1 of the first embodiment, a detection route 7 is arranged between different poles of an electric circuit 2 connected to a load resistance. This detection route 7 is one in which the capacitor 3 and the measured portion 5 are arranged in series, and the measured portion 5 in the first embodiment is a resistor. The part to be measured 5 is an element measured by the measuring means 9, and an element whose measurement result differs depending on the presence or absence of a discharge accident. More specifically, the current normally flows as indicated by the arrow in FIG. Therefore, almost no current flows through the detection route 7. On the other hand, when a discharge accident occurs in the electric line 2 such as when tracking occurs, a high frequency noise current is superimposed on the commercial power supply. Therefore, as shown by the arrow in FIG. 2, a predetermined current also flows in the detection route 7. Therefore, it is possible to make a difference in the measurement result depending on the presence or absence of the discharge accident. Further, since such a means is adopted, unlike the case where the light emitting element detects the light emitting phenomenon due to the discharge accident, the position where the discharge accident occurs and the position of the detection route 7 are distant from each other. Can also detect a discharge accident.

This is possible because the characteristics of the capacitor 3 are used. The impedance of the capacitor 3 has a characteristic that the magnitude of the impedance of the capacitor 3 is different for each frequency (hereinafter, referred to as frequency characteristic), as shown in the following equation.
Z = 1 / j2πfC
(Z: impedance, j: imaginary number, f: frequency, C: capacitance of capacitor)

For example, in the case of direct current, no current normally flows. On the other hand, current flows mainly in a specific frequency band of high frequency. This is because the impedance becomes small. By utilizing this property, the detection route 7 is set to a state in which almost no current flows in the detection route 7 with respect to the normal commercial frequency (for example, 50 to 60 Hz), and the detection route 7 is generated when a specific high frequency band occurs. It is possible to set a state in which a current flows. Since the frequency characteristic of the impedance varies depending on the type of the capacitor 3, it is possible to obtain the desired performance relatively easily by selecting the capacitor 3 having the desired frequency characteristic.

The detection route 7 of this embodiment employs a CR circuit. The resistance of this CR circuit is used as the measured portion 5 of the detection route 7. The measuring means 9 of the present embodiment can measure the voltage, and is arranged so as to measure the voltage across the resistance. The difference in the measurement results when such measuring means 9 is adopted will be described with reference to FIGS. 3 and 4. FIG. 3 is an example of a voltage waveform when tracking is not occurring. Further, FIG. 4 is an example of a voltage waveform when tracking occurs. As can be understood from the matters shown in FIG. 3, almost no voltage is measured when the commercial power source is used alone. On the other hand, when the tracking as shown in FIG. 2 occurs, the voltage waveform as shown in FIG. 4 is measured. Since the voltage value changes by changing the resistance value, the desired performance can be obtained relatively easily by selecting the resistor so that the desired voltage value can be measured.

The discharge accident detection system 1 according to the present embodiment is provided with the determination means 8. Any determination may be made by the determination means 8. For example, it is possible to determine that a discharge accident has occurred when a threshold value that is a specific set value is exceeded. In this case, the threshold value may be set to a value larger than the value measured when no discharge accident has occurred. In FIG. 4, an example of the threshold value is shown by a broken line. In this case, if the threshold value is exceeded even once, it is determined that a discharge accident has occurred.

In addition, it is possible to determine that a discharge accident occurs when the threshold value is exceeded multiple times. In this case, it is also possible to determine that a discharge accident has occurred when a state in which the threshold value is exceeded exceeds the set number of times within a certain period of time. By doing so, it becomes possible to distinguish the switching noise generated when the power of the device is turned on and the noise caused by the discharge accident.

Next, a second embodiment will be described. FIG. 5 is a schematic diagram of the second embodiment. In this embodiment, two CR circuits are provided between the different poles of the electric path 2. In addition, one CR circuit includes a capacitor 3 having a different impedance frequency characteristic from the impedance of the capacitor 3 included in the other CR circuit. The measurement result obtained by the measuring means 9 for measuring one measured portion 5 and the measurement result obtained by the measuring means 9 for measuring the other measured portion 5 are sent to the judging means 8. The determination means 8 compares the measurement results and determines the presence or absence of a discharge accident. For example, if two CR circuits having different frequency characteristics are provided, and the measuring means 9 of one CR circuit exceeds the threshold value, but the measuring means 9 of the other CR circuit does not exceed the threshold value, a discharge accident occurs. It is also possible to improve the detection accuracy by determining that they are not, and when both of them exceed the threshold value, it is determined that there is a discharge accident. Further, even if two CR circuits are provided between different poles and the frequency characteristics of the impedances of the capacitors 3 provided in both CR circuits are the same, a discharge accident occurs if both measuring means 9 exceed the threshold value. The detection accuracy may be improved by determining that.

In the description of these embodiments, the tracking phenomenon that occurs in an outlet plug or the like is described, but it is also possible to detect a short circuit accident of the wiring cord or a wire cord disconnection accident. For example, the short circuit protection of the wiring cord by the breaker is not interrupted unless the short circuit current flows for more than half a cycle. On the other hand, with the configuration for detecting high-frequency noise that occurs when a short circuit occurs as in the present embodiment, it is possible to detect even less than half a cycle. By utilizing this, it is possible to process the short-circuit accident earlier.

Although the two embodiments have been described above, the present invention is not limited to the above-mentioned embodiments, and can have various modes. For example, the measuring means does not have to measure the voltage. For example, current or magnetic field may be measured. Further, the measured portion may not be the resistance.

It is also possible to improve the detection accuracy of the discharge accident by further performing frequency analysis on the measured waveform of the high frequency noise. Further, by separately using a noise filter to attenuate a specific frequency band, it is possible to improve the accuracy of detecting a discharge accident.

Furthermore, by periodically recording and accumulating the voltage waveform detected by the measuring means, the determining means is allowed to retain the function of learning the voltage waveform during normal operation, and the abnormal waveform caused by the discharge accident and the normal time It is also possible to improve the accuracy of detection of discharge accidents by comparing with the waveform.

It is also possible to adopt a configuration in which the warning means gives a warning when a discharge accident is detected by the judging means.

Further, the CR circuit provided between the different poles of the electric path may be a plurality of three or more. In this case, if at least one CR circuit is a capacitor different from the frequency characteristics of the impedance of the capacitors provided in the other CR circuits, it is possible to compare the differences in the frequency characteristics. Of course, all capacitors may have different frequency characteristics, or may have the same frequency characteristics. In any case, the determination means can determine the presence or absence of a discharge accident by comparing the measurement results of the measured parts of the CR circuits.

In addition, since the frequency of occurrence varies depending on the content of the accident, if multiple detection routes are set and capacitors with frequency characteristics corresponding to each accident are distributed and installed on each detection route, multiple types of It is possible to respond to an accident.

The discharge accident of the AC electric circuit has been described above, but the DC electric circuit may be used. In the case of a direct current circuit, normally, the capacitor is charged, and the property that no current flows in the CR circuit is used.

1 Discharge accident detection system 2 Electric circuit 3 Capacitor 5 Measured part 7 Detection route 8 Judgment part 9 Measuring means

Claims (2)

A detection system for tracking phenomenon that occurs in an outlet plug,
The detection route consisting of CR circuits arranged a capacitor and resistor in series, a plurality placed between different poles of the commercial power supply path,
The measuring means for measuring the voltage value applied to both ends of the resistor, and the judging means for judging the tracking phenomenon based on the measurement result of the measuring means are provided . The detection system of the tracking phenomenon performed when all the voltage values measured by the respective measuring means exceed the threshold value . Among the plurality of detection routes, frequency characteristics of the capacitor of the CR circuit disposed on at least one of the detection route, the 請 Motomeko 1 that is different from the frequency characteristic of the capacitor of the CR circuit which is disposed on the other of the detection route The described tracking phenomenon detection system.

Images