JPH03242561A - Apparatus for measuring insulation resistance - Google Patents

Abstract

PURPOSE:To prevent damage of an electronic machine due to residual charge by providing a potential measuring means for certifying discharge of the residual charge in an object to be measured. CONSTITUTION:Relays RL1, RL5 are turned ON at the time of measurement so that high voltage of a high voltage generator is applied to a selection wire via a measurement lines ML1, ML2 and a path switch 11, and insulation resistance is measured by a measurement unit 13. The value is rectified in a rectifier 18 and processed in a control unit 20 through an A/D converter 19. When the measurement is completed, the relays RL1, RL5 are turned OFF and relays RL2, RL4 are turned ON so that stored charge is discharged via the relay RL2 as well as residual voltage is detected by a differential amplifier 14 and processed in the control unit 20 through an amplifier 15, the rectifier 18 and the A/D converter 19. The control unit 20 determines completion of the discharge when the residual voltage is lower than a predetermined value.

Description

[Detailed Description of the Invention] (W Required) An insulation resistance measuring device for measuring the insulation resistance of objects to be measured such as communication lines and other electrical structures, which prevents damage to electronic equipment due to residual charges and provides safety. The purpose of the present invention is to provide an insulation resistance measuring device having two terminals for measuring the insulation resistance of an object to be measured, which measures the insulation resistance by applying a voltage to the object to be measured. An insulation resistance measuring means for performing the measurement, a discharging means connected to the terminal for discharging the charge remaining in the object to be measured, and a means for ensuring discharge of the charge remaining in the object to be measured. The electric potential measuring means is configured to include a potential measuring means for measuring the potential of the object to be measured, and a comparing means for comparing the measured value by the potential measuring means with a reference value.

[Industrial Application Field] The present invention relates to an insulation resistance measuring device for measuring the insulation resistance of objects to be measured such as communication lines and other electrical works.

In recent years, data communication systems in which a computer and a large number of terminal devices are connected through communication lines have become rapidly popular.

In general, when a fault occurs in a communication line or other line, there is a risk that computers and terminal equipment connected to the line may malfunction. The social impact of this is extremely large.

Therefore, it is extremely important to prevent line failures and to promptly remove the failures should they occur.

[Conventional technology]

2. Description of the Related Art Conventionally, insulation resistance measurements have been carried out using insulation resistance meters (meggers) in order to test the presence or absence of insulation deterioration of various objects to be measured, such as communication lines and other electrical structures.

Generally, a relatively high voltage of about 100 to 2,000 volts is used for measurements with an insulation resistance meter, and it is possible to detect defects that cannot be detected with circuit testers or electronic testers, which measure voltages as low as a few volts. Therefore, it is often used to check for defects in the track during inspections at the end of track construction work and during maintenance work.

However, when measuring with an insulation resistance meter, the 'IS path is charged with a voltage of several hundred volts, and the charge remains even after the measurement is completed. Therefore, if electronic devices such as computers, terminal devices, or OA equipment are connected after measurement, they may be damaged.

To solve this problem, an insulation resistance measuring device has been proposed that connects a discharge resistor to the object to be measured to discharge the residual charge of the object after measuring the insulation resistance. No. 56-13760).

[Problems to be Solved by the Invention] However, with the conventional insulation resistance measuring device described above, it is not possible to determine whether or not the residual charge has been completely discharged. The connection between the insulation resistance measuring device and the object to be measured may be disconnected even though there is still residual charge, which still poses a safety problem.

Therefore, in order to prioritize safety, it is necessary to connect the discharge resistor to the object under test for a long time, which makes insulation resistance measurement unnecessarily long and makes it difficult to use. was bad. For this reason, the use of insulation resistance measuring devices in the field is often avoided, and short circuits or faults in the line cannot be completely detected, which may lead to unexpected failures.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a highly safe insulation resistance measuring device that prevents damage to electronic equipment due to residual charges.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the insulation resistance measuring device according to the present invention has two terminals MLI for measuring the insulation resistance of the object to be measured 4, as shown in FIG. , 2, an insulation resistance measuring means 12.13 for applying a voltage to the object to be measured 4 to measure insulation resistance;
a discharge means RL2 connected to the terminal ML1.2 for discharging the charge remaining on the object to be measured 4; and a discharge means RL2 connected to the terminal ML1.2 for discharging the charge remaining in the object to be measured 4; The electric potential measuring means 14 measures the electric potential of the electric potential measuring means 14, and the comparing means 20a compares the measured value by the electric potential measuring means 14 with a reference value.

[Function] The insulation resistance measuring means 12.13 applies a voltage to the object to be measured 4 to measure insulation resistance.

The discharge means RL2 discharges the charge remaining in the object to be measured 4.

The potential measuring means 14 measures the potential of the object to be measured 4 connected to the terminal MLI, 2 in order to confirm discharge of the charge remaining in the object to be measured 4.

The comparing means 20a compares the measured value by the potential measuring means 14 with a reference value.

〔Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an insulation resistance measuring device 1 showing an embodiment of the present invention.
FIG.

The insulation resistance measuring device l includes a line switching section 11, a high voltage generating section 12, a measuring section 13, a differential amplifying section 14, an amplifying section 15,
Rectification section 18, AD conversion section 19, control section 20, memory 21
, a display section 22, a key manual section 23, an alarm buzzer 26, etc. are provided.

The line switching unit 11 includes a connector or a terminal block, a relay contact, etc. for connecting the cable 4, and switches between the electric wires L1 to 8 and the ground wire E of the cable 4 in response to a switching signal from the control unit 20, which will be described later. A pair of electric wires is selectively connected to the measurement line MLI,2.

Hereinafter, the wire pairs connected by the line switching unit 11 will be described as "
It is sometimes referred to as "selective wire".

The high voltage generator 12 generates a high voltage, for example, 250 volts of DC.

The measurement unit 13 outputs a measurement signal S5 corresponding to the magnitude of the current flowing through the selected wire.

The differential amplification unit 14 differentially amplifies the input signals S1 and 2 inputted to the measurement line ML1.2. As a result, a difference signal S3 corresponding to the potential between the selected wires is output from the differential amplifier section 14. Note that the differential amplifier section 14 also acts as a buffer for high voltage input.

The amplifying section 15 amplifies the difference signal S3 from the differential amplifying section 14 at a constant amplification factor. This amplification factor can be switched depending on the person's boyfriend/L4.

The rectifier 18 rectifies the input signal (S4 or S5), and smoothes and shapes the waveform as necessary.

The AD converter 19 quantizes the output from the rectifier 18 and converts it into an insulation resistance value DM or residual voltage value DR, which is a digital value.

The control unit 20 consists of a microprocessor sensor, 10 elements, and other peripheral elements, and reads the insulation resistance value DM and residual voltage value DR from the AD converter 9, reads/writes data to the memory 21, and displays the data. The comparator 20a compares the residual voltage value DR with a reference value Ds (for example, 5 volts), and sets a timer based on a clock signal. outputs a switching signal for the line switching unit 11, and controls the entire insulating paper (fL measurement device r) by operating a relay (not shown) to switch its contacts RL 1 to 5.

The memory 21 consists of ROM, RAM, etc., and stores programs necessary for control by the control unit 20 and 4 DI.
It stores the value Ds, etc., and also stores various data read or commanded by the control unit 20.

The display section 22 is composed of a finished product panel of an appropriate size, and displays the comparison results of the insulation resistance value DM and the residual voltage value DR1 in the control section 20, as well as other information.

The key manual section 23 consists of a numeric keypad, control keys, etc.
It is used to manually input setting data and command data.

The alarm buzzer 26 sounds when there is an abnormality in insulation resistance measurement.

Next, the operation of insulation resistance measurement by the insulation resistance measuring device 1 will be explained with reference to the flowchart shown in FIG.

FIG. 2 is a flowchart showing the insulation resistance measuring operation by the insulation resistance measuring device 1. As shown in FIG.

First, contact RL1.5 is turned on, and measurement line ML1.2
A high voltage is applied to the selected electric wire via the line switching unit 11, and the insulation resistance is measured (step #11). The measurement signal S5 from the measurement section 13 is converted into an insulation resistance value DM via the rectification section 18 and the AD conversion section 19, and is input to the control section 20.

When the insulation resistance measurement is completed, contact RLI, 5 is turned off.
Contact RL2 is turned on, and the residual charge between the selected wires is discharged through contact RL2 (step #12).

Next, contact RL2 is turned off, contacts RL3 and 4 are turned on, and the residual potential of the selected wire is measured (step #13
). At this time, the input signal S input manually to the differential amplifier section 14
1.2 is the amplification section 15, contact RL4, rectification section 18, AD
It is converted into a residual voltage value DR via the converter 19, and then sent to the controller 2.
It is input to 0.

The residual voltage (aDR) is compared with the reference value Ds by the comparator 20a (step #I4).

If the residual voltage value DR is lower than the reference value Ds, a message indicating that the discharge of the residual charge has been completed and the insulation resistance value D
M is displayed on the display section 22 (step #16).

If the residual voltage value DR is high, the alarm buzzer 26 is sounded (step #15), and a message indicating that the residual charge is not sufficiently discharged and the insulation resistance value DM are displayed on the display section 22 (step #15).

In each step #11.12.13 described above, the line switching unit 11 is switched and performs the respective processing for all necessary combinations of electric wires L1 to L8 and ground wire E (that is, all selected electric wires). is executed.

Note that steps #11 to #1 above are performed for one selected wire.
The 16 processes may be performed consecutively. In that case, it would be safer to automatically switch to the next selected wire only when the residual voltage value DR is lower than the reference (+1!Ds).

According to the above embodiment, after the insulation resistance measurement is performed, the residual charge is discharged, and after the discharge, it is confirmed whether the lightning has been completely discharged, and the discharge of the residual charge is completed. Since the measurement result is displayed on the display unit 22, electronic equipment can be connected to the cable 4 after measurement with peace of mind.

Furthermore, if the residual charge is not sufficiently discharged, this fact is displayed on the display section 22 and notified by the T-alarm buzzer 26, thereby preventing damage to the electronic device by connecting it. At the same time, the electric wire L1 with residual charge remains
By discharging only 8 again, all electric wires L
1 to 8 can be reliably discharged in a short time.

Therefore, the insulation resistance measurement using the insulation resistance measuring device 1 is safe, and the time required for measuring the insulation resistance does not become unnecessarily long, which improves the usability of the insulation resistance measuring device 1, thereby promoting its use. Ru. This makes it easy to discover line defects, prevents failures, and improves the reliability of the data communication system using the cable 4.

In the above embodiment, instead of the differential amplification section 14, one input may be grounded and the other input may be amplified by a normal amplifier. A resistor of an appropriate value may be connected in series with contact RL2.

The voltage of the high voltage generating section 12 or the magnitude of the reference (11!DS) may be a value other than the above. The reference value Ds may be settable by the key human power section 23. The difference signal output from the differential amplifier section 14 S3 may not be converted into a digital value, but may be configured to be compared with a reference voltage using an appropriate comparator.In addition, the configuration of each part of the insulation resistance measuring device I can be modified in various ways other than those described above.

The insulation resistance measuring device 1 as described above can be applied to measuring the insulation resistance of various cables other than the cable 4, other communication lines, power supply lines, other electric works, and the like.

[Effects of the Invention] According to the present invention, it is possible to provide a highly safe insulation resistance measuring device that prevents damage to electronic devices and the like due to residual charges.

[Brief explanation of drawings]

FIG. 1 shows an insulation resistance measuring device 1 showing an embodiment of the present invention.
FIG. 2 is a flowchart showing the insulation resistance measuring operation by the insulation resistance measuring device 1. In the figure, 1 is an insulation resistance measuring device, 4 is a cable (object to be measured), 12 is a high voltage generation section (insulation resistance measuring means), 13 is a measuring section (insulation resistance measuring means), and 14 is a differential amplifier section (potential 20a is a comparison section (comparison means), ML12 is a measurement line (terminal), and RL2 is a contact (discharge means).

Claims (1)

[Claims] (1) Insulation resistance measuring device (1) having two terminals (ML1) (ML2) for measuring the insulation resistance of the object to be measured (4)
), comprising insulation resistance measuring means (12) (13) for measuring insulation resistance by applying a voltage to the object to be measured (4).
), a discharging means (RL2) connected to the terminals (ML1) (ML2) for discharging the charge remaining on the object to be measured (4), and discharging means (RL2) connected to the terminals (ML1) (ML2) for discharging the charge remaining on the object to be measured (4); It has a potential measuring means (14) for measuring the potential of the object to be measured (4) in order to confirm discharge, and a comparing means (20a) for comparing the measured value by the potential measuring means (14) with a reference value. An insulation resistance measuring device characterized by: