JP2000055962A - Wiring tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring tester for searching the open-phase and the contact fault of a low voltage wiring for power in a power interruption time without requiring a large manpower in a short time without power interruption. SOLUTION: A connecting cable 1 is connected to an electric wire of a position to be searched for a fault. An input/output processor 2 voltage divides a voltage between lines of an input, and an analog processor 3 full-wave rectifies it. A microcomputer 4 samples an input, converts it into a digital value, and moving averages to obtain an effective voltage value. If the effective voltage value is a value near 0 V it is decided as an open-phase. If it is a value near 90 V, it is decided as a contact fault. The microcomputer 4 has a means for recording the decision result of the open-phase and the contact fault. The judgment of whether it is an intermittent open-phase or contact fault or not is facilitated by the record.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring tester, and more particularly to a wiring tester capable of effectively detecting an open phase and a contact failure of a low voltage power wiring.

[0002]

2. Description of the Related Art When an open phase or poor contact occurs in a low-voltage power line, an earth leakage breaker operates to cause a power outage. Therefore, it is possible to quickly find a fault location and restore it to a normal state. is necessary. Here, the definitions of the phase loss and the contact failure will be described with reference to FIGS.

As shown in FIG. 4 (a), in a normal single-phase three-wire, a voltage of 100 V is applied between the respective wires, but as shown in FIG. If, for example, a disconnection occurs at a point P1 of one line, the voltage applied to the load becomes 0V. This state is an open phase. In the normal case, a voltage of (101 ± 5) V is applied to the load, as shown in FIG. When an obstacle such as a short cut occurs, a contact resistance Rs that does not exist in a normal case occurs, and a voltage drop occurs here. Therefore, only a voltage of 96 V or less is applied to the load. This state is poor contact.

FIG. 6 is a diagram showing general low-voltage power wiring. In the figure, 21 is an ordinary watt hour meter (WHM) connected to the low-voltage power wiring, 22 is a current limiter (ACL),
23 is an earth leakage breaker (ELB), 24a to 24c are NFB
(no fuse break), and electric power is supplied to power devices such as a kitchen, a Western-style room, and a Japanese-style room via the NFBs 24a to 24c. The current limiter 22 detects an overcurrent when the total load of power devices connected after the current limiter 22 exceeds the rating of the current limiter 22 (overload), and shuts off itself. Has a function. Further, the earth leakage breaker 23 has a function of monitoring an overvoltage and an earth leakage current of the low-voltage wiring and shutting off itself when such a phenomenon occurs.

In the case where a fault occurs in the low-voltage wiring for electric power as shown in FIG. 6, the following operation has conventionally been performed in order to identify the location where the fault has occurred.

(1) The current limiter 22 and the earth leakage breaker 2
3. With the NFBs 24a to 24c turned on, wiring between these devices, for example, under the ceiling, cords of electric devices,
Investigate whether or not the state changes by touching or shaking the low-pressure drop line or the like. (2) If no abnormalities are found by the above investigation, move on to a more detailed investigation. The low-voltage drop line is again examined for abnormality, and if no abnormality is found, the current limiter 22 is checked.
It is determined that there is an abnormality further downstream.

(3) Next, the NFBs 24b and 24c are separated from the wiring, and it is checked whether there is any abnormality in the wiring of the NFB 24a or the power equipment. If there is no abnormality, the NFB 24a is separated from the wiring, and the resistance between the wirings is measured. If an infinite resistance is measured by this measurement, it is determined that a normal contact is detected.

(4) If there is no abnormality in the wiring of the NFB 24a or the power equipment, disconnect the NFBs 24a and 24c from the wiring and perform the same operation as described above to determine whether there is any abnormality in the wiring of the NFB 24b or the electric equipment. Confirm.
If there is no abnormality in the wiring of the NFB 24b or the power equipment, the NFBs 24a and 24b are separated from the wiring, and it is confirmed whether there is any abnormality in the wiring of the NFB 24c or the power equipment by the same operation as described above.

(5) If the fault location can be identified by the above operation, the system related to the fault location is disconnected and the fault is restored. Finally, make sure that the power is supplied normally.

[0010]

However, the above-described conventional fault location searching method has the following problems. That is, since the power low-voltage wiring line generally has various branches, it takes a great deal of labor and time to specify the fault location by the above-mentioned operation. In searching for a fault location, the location to be investigated is separated from the system and the resistance between wirings is measured. Therefore, during the investigation, you will lose power for a while,
As a result, it was another problem that bothered consumers.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the prior art, and to investigate open phases and poor contact of low-voltage wiring for power without a great effort and in a short time. It is an object of the present invention to provide a wiring tester that can be performed without using a wiring tester. Another object of the present invention is to provide a wiring tester capable of detecting an intermittent open phase and a contact failure occurring within a predetermined time.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is a wiring tester for detecting an open phase and a contact failure of a low-voltage power wiring, and includes an electric wire for detecting a failure. An effective voltage value is obtained from a connection cable to be connected and an input taken through the connection cable, and if the effective voltage value is 0 V or less than a first threshold value in the vicinity thereof, it is determined that there is no phase, and 90 V is determined. Alternatively, a first characteristic is that a means for judging a contact failure if it is equal to or less than a second threshold value in the vicinity thereof is provided. A second feature is that a means for recording the determination result of the phase loss or the contact failure is provided.

[0013] According to the first feature, a fault of open phase or poor contact can be detected by a simple operation of simply connecting the wiring tester to the electric wire and instructing the wiring tester to start a test. Become like Further, according to the second feature, it is possible to easily and accurately determine whether or not the fault of the open phase or the poor contact is intermittent.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of a wiring tester 10 according to the present invention. In the figure, 1 is a connection cable connected between each line of the low-voltage power wiring for exploring a fault location, and 2 is a size that can divide the input taken through the connection cable 1 and input it to the microcomputer circuit 4. An input / output processing circuit that converts the voltage into a maximum voltage value of about several volts,
Reference numeral 3 denotes an analog processing circuit for performing full-wave rectification of the input. Reference numeral 4 denotes a sampled and full-wave rectified input, which is converted into a digital value, and a moving average of the sampled value is taken to obtain an effective voltage value (hereinafter referred to as an effective value). ), And a microcomputer circuit for determining open phase and contact failure from the effective value, and a key input 5 for selecting a type of investigation of the low-voltage power wiring and instructing the start of the selected investigation. A processing circuit 6 is a display circuit for displaying the processing results of the microcomputer circuit 4, and 7 is a power supply circuit such as a battery. The microcomputer circuit 4 also has a function of recording the results of investigations such as phase loss and poor contact, and determining whether or not an intermittent failure has occurred.

The wiring tester 10 according to the present embodiment can perform various measurements such as a pass / fail judgment of an earth leakage breaker, a voltage measurement, a load current measurement, and an insulation resistance measurement, in addition to the above-described investigation of the open phase and the contact failure. Selection of an inspection item can be performed by the key input processing circuit 5. Although the megger circuit is a circuit for measuring the insulation resistance of the wiring, it is not related to the present invention, and therefore, the description is omitted.

FIG. 2 shows a wiring tester 10 shown in FIG.
The wiring tester 1 for detecting a fault in a single-phase three-wire neutral conductor
It is a figure which shows the connection state of 0. In the figure, 11 indicates a neutral conductor, 12 indicates a ground fault circuit breaker, 13 indicates a load in an open state, and other reference numerals indicate the same or equivalent parts as those in FIG. Note that only the main part of the wiring tester 10 is shown.

As shown, the connection cable 1 of the wiring tester 10 is connected to two wires in a wiring section to be examined. The wiring tester 10 performs the processing shown in the flowchart of FIG. 3 on the input (line voltage) taken in from the two wires, thereby performing a fault such as an open phase or poor contact in the wiring section. It is determined whether or not is occurring.

Next, the operation of this embodiment will be described with reference to FIG. When the wiring tester 10 is connected to the low-voltage power wiring as shown in FIG. 2 and a test start command is issued from the key input processing circuit 5 (Yes at Step S1), the microcomputer circuit 4 proceeds to Step S2. The input that has been full-wave rectified by the analog processing circuit 3 is sampled and A / D converted. In step S3, the digital signal obtained by the A / D conversion is moving averaged to determine the effective value of the input. In step S4, the effective value is input to 10
It is determined whether or not it is equal to or less than a first threshold value when converted to 0V. The first threshold value is theoretically 0 V, but it is preferable that the first threshold value be 10 V or less in an actual device.

When the determination is affirmative, the routine proceeds to step S5, where it is determined that the phase is open. This determination result is displayed on the display circuit 6, and when it is determined in step S9 that there is a change in the determination result, in step S10,
The result of the determination is stored in a storage device (not shown) of the microcomputer circuit 4. On the other hand, when the determination in step S4 is negative, the process proceeds to step S6, where the calculation result is the second value.
It is determined whether it is equal to or less than the threshold value. It is to be noted that about 90 V is appropriate as the second threshold value, but it is sufficient if the second threshold value is in the vicinity thereof. If the determination in step S6 is affirmative, the process proceeds to step S7, where it is determined that the contact is poor. If the determination in step S6 is negative, the process proceeds to step S8, where it is determined that the operation is normal. This determination result is also recorded in step S10 when the determination in step S9 is affirmative.

Subsequently, in step S11, it is determined whether or not a command to end the test has been issued from the key input processing circuit 5. If this determination is negative, step S
2, the same operation as described above is repeatedly performed.

During the repetitive execution, the electric wire connected to the wiring tester 10 is touched or shaken by the operator. As a result, for example, when the effective value calculation result in step S3 changes from a state equal to or less than the first threshold to a state equal to or more than the first threshold and equal to or less than the second threshold, the recording in step S10 includes a change from the open phase state to the poor contact. The change to the state is recorded. This record may be just the change,
A time at which the change has occurred may be added. Step S1
If it is determined in step 1 that the key input processing circuit 5 has issued a command to terminate the test, the measurement of the phase loss and the contact failure is terminated.

Therefore, according to the present embodiment, it is determined whether or not the wire at the location under investigation has an open phase or poor contact, and whether or not the open phase or the poor contact is intermittent. Can be determined at the same time. That is, if the recording result of step S10 changes from the poor contact state to the normal state during the measurement, or if the change in both directions between the poor contact state and the normal state occurs a plurality of times during the measurement, The poor contact state can be determined to be intermittent. Further, according to the present embodiment, even if the change occurs a plurality of times in a non-visual cycle of, for example, 1 second or less, since it is accurately recorded, the intermittent contact failure that is missed by the conventional method, Alternatively, instantaneous interruption or the like can be reliably detected, and the measurement accuracy is greatly improved as compared with the related art.

As described above, the present invention has been described with reference to one embodiment. However, the present invention is not limited thereto, and various modifications are possible. Modifications which do not depart from the gist of the present invention are described below. Obviously, it falls within the range.

[0024]

As is apparent from the above description, according to the present invention, the occurrence of phase loss and poor contact can be achieved by a simple operation of simply connecting a wiring tester to an electric wire to be investigated and without a power failure. You will be able to investigate the location. In addition, since this investigation can be performed in a short time, the time from the occurrence of a failure to recovery can be significantly reduced as compared to the conventional investigation, and power outages for fault detection and recovery can be performed. The time can be greatly reduced. Also, the number of working personnel is smaller than in the conventional case, and the working efficiency can be greatly improved.

Further, the determination result of the phase loss or the contact failure is recorded, and if a change is found in the determination result, it can be determined that the intermittent phase loss or the contact failure is present. For this reason, it is possible to accurately and easily determine the intermittent open phase or poor contact.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a wiring diagram showing a connection state of a wiring tester to an electric wire.

FIG. 3 is a flowchart showing the operation of the embodiment.

FIG. 4 is an explanatory diagram of an open phase state.

FIG. 5 is an explanatory diagram of a contact failure.

FIG. 6 is a wiring diagram illustrating an example of low-voltage wiring for electric power.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Connection cable, 2 ... I / O processing circuit, 3 ... Analog processing circuit, 4 ... Microcomputer circuit, 5 ... Key input processing circuit,
6: display circuit, 7: power supply circuit, 11: neutral wire, 12: earth leakage breaker, 13: load in open state.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Isao Moriyama 2-82 Watanabe-dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture Inside Kyushu Electric Power Co., Inc. 1-82 Kyushu Electric Power Co., Inc. (72) Inventor Shiro Matsuda 4-18-18 Shimizu, Minami-ku, Fukuoka City, Fukuoka Prefecture Kyushu Electric Manufacturing Co., Ltd. (72) Inventor Masahiko Ikeda Shimizu, Minami-ku, Fukuoka Prefecture Kyushu Electric Manufacturing Co., Ltd. 4-chome 19-18 Kyushu Electric Manufacturing Co., Ltd. (72) Inventor Koji Inaba 4-19-19 Shimizu Minami-ku, Fukuoka City, Fukuoka Prefecture Kyushu Electric Manufacturing Co., Ltd. 4-19-19, Shimizu, Minami-ku, Kyushu Electric Manufacturing Co., Ltd. F-term (reference) 1 AD58 AD65

Claims (5)

[Claims] 1. A wiring tester for detecting an open phase and a contact failure of a low-voltage power wiring, comprising: a connection cable connected to an electric wire for which a fault is to be detected; An effective voltage value is obtained from the input, and if the effective voltage value is equal to or less than 0 V or a first threshold value in the vicinity thereof, it is determined that there is no phase. If the effective voltage value is equal to or less than 90 V or a second threshold value in the vicinity thereof, it is determined that there is a contact failure. And a wiring tester. 2. The wiring tester according to claim 1, further comprising: means for dividing an input taken through the connection cable and performing full-wave rectification, wherein the effective voltage is supplied from the full-wave rectified input. A wiring tester characterized in that a value is obtained. 3. The wiring tester according to claim 1, further comprising a recording unit that records a determination result of the phase loss or the contact failure. 4. The wiring tester according to claim 3, wherein the recording unit records the determination result only when there is a change in the determination result. 5. The wiring tester according to claim 3, wherein said recording means adds time to said determination result.