JPS59228171A - Measurement of line constant - Google Patents

Abstract

PURPOSE:To enable the measurement of the line constant between two equipments with minimized leading wires by supplying power from one equipment with the connection of the equipments using four wires by a transformer connection. CONSTITUTION:Equipments A and B are connected with four wires A-D two wires each and are connected to transformers IND0 and IND1 in the equipment A and to transformers IND3 and IND4 in the equipment B respectively. An relay (a), a DC ammeter and a resistor Ro are connected in series between the make contact of a relay SPb inserted into a line B and a positive electrode of a power source and additionally, a relay (b), a DC ammeter and a resistor R1 done between a make contact of a relay SPd inserted into a line D and a negative electrode of the power source to form a measuring apparatus. In the apparatus thus formed, for example, when the line resistance between A and B is measured, the relay SPb and the relay (a) are operated to put the contact to the condition as shown by the dotted line as illustrated. When the line resistance between D and E is measured, the relay SPd and the relay (b) are operated to put the contact to the condition as shown by the dotted line.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides two wires each out of the four wires drawn into the own device.
By coupling each to two transformers, there are four
By connecting the negative terminal of the power supply to the midpoint of one transformer of one device, and the positive pole of the power supply, which has the same potential as the earth, to the midpoint of the other transformer, the power supply can be connected to the other device. The present invention relates to a method for measuring line constants between two devices to which power is supplied.

When attempting to measure line constants between the above devices, conventionally all four wires were drawn into the measuring device and measured. Therefore, when the number of devices to be measured increases, the number of lead-in circuits to the measuring devices becomes enormous, and a large amount of hardware is required.

The object of the present invention is to combine four wires by transformer coupling,
An object of the present invention is to provide a method for measuring a line constant by which the line constant V between two devices configured to supply more stain force than one device can be measured using a lead-in line with less electric force.

In order to achieve the above object, the method for measuring line resistance according to the present invention connects two of the four wires drawn into the device to two transformers, thereby connecting four wires between the devices.
By connecting the negative terminal of the power supply to the midpoint of one transformer of one device, and the positive pole of the power supply, which has the same potential as the earth, to the midpoint of the other transformer, the power supply can be connected to the other device. In the method of measuring the line Z convergence between two devices to which one power is supplied, one of the two wires respectively connected to the two transformers is pulled out, and one device is connected to the positive terminal of the power source. The negative electrode is drawn out, and a measuring device such as a DC ammeter or a resistor is connected between the drawn lines to measure the constant of the inter-device line.

Embodiments of the method of the present invention will be described below with reference to the drawings.

FIG. 1 is an example of a measuring device for measuring line resistance between devices in a first embodiment of the method of the present invention.

The 4 wires A, B, O, and D that connect devices A and B are in units of 2 wires, and in device tA, transformers INDo and IN
In device B, transformers IND3 and IND
4 are connected to each other. Transformer IN on device B side
The negative pole of the power supply -48V is connected to the midpoint of D2, and the transformer IND3
The positive pole of the -48V power supply, that is, the ground, is connected to the midpoint of the power supply, and power is supplied from the device B to the device AK.

Output lines are 2 lines from line B of 2 lines A and B, and E
The positive and negative electrodes are respectively drawn out from the D line of the two, and the positive and negative electrodes are drawn out from the -48V power supply of the device B. Connect the A relay, DC ammeter ■, and resistor Ro in series between the S P B IJ relay make contact inserted in the B wire and the positive electrode (earth) of 1#t, and then connect the SPD inserted in the D wire. A measuring device is constructed by connecting a B relay, a DC ammeter (2), and a resistor R1 in series between the make contact of the relay and the negative electrode of the power source. When measuring the line resistance between AB,
Operate the S P B IJ relay and the A relay, and set their contacts to the position shown by point p- in the figure.

The current is the ground (G) of device B → Fixed resistance 0- + Jl current meter ■ → Center of contact a of A relay → Make contact of contact a →
Make contact of contact spb of relay 8PB → center of contact spb → No. 5 terminal of transformer INDO → transformer IND
It flows in the path of No. 4 terminal of O → No. 1 terminal of transformer IND2 → No. 2 terminal of transformer IND2 → Power supply of unit gB.

If the current flowing through the path at this time is IAB (A), then
The line resistance RAB (Ω) between AB can be found as follows. Note that here, RC0IL is the DC resistance of transformers INDO and IND2.

Next, when measuring the line resistance between DE, operate the SPD relay and B relay, and set their contacts to the positions shown by the dotted lines in the figure. The current is from the earth (G) of device B → transformer I
2-position terminal of ND3 → No. 3 terminal of transformer INDa → 5-position terminal of transformer NDl → 4-position terminal of transformer INDl → Center of SPD relay contact spd → Make contact of contact spd → Center of B relay contact → Flows through the path of the make contact of contact point → ammeter → resistor R1 → power supply of device B. If the current flowing through the path at this time is Ing (A), it can be determined by the line resistance between DB and DB. Note that RCOIL is the DC resistance of transformers IND1 and IND3.

Next, a second embodiment of the method of the present invention will be described. Second
The figure is an example of a measuring device that measures the line capacitance OAR between the lines AB and the line capacitance 0Dva between the lines DB. Device A
, B and the four-wire configuration between devices A and B is the same as in FIG.

A Q IJ relay and a resistor R2 are connected in series between the make contact of the SPB relay inserted in the B line and the positive pole (earth) of the power supply, and a D relay and a capacitor Co are connected in series between the negative pole of the power supply. 5PD connected and inserted into D line
A measuring device is constructed by connecting an E relay and a resistor R4 in series between the make contact of the IJ relay and the negative pole of the power supply, and further connecting a li' IJ relay capacitor C1 in series between the positive pole (earth) of the power supply. is configured.

To measure the line capacitance between At(), first operate the SPB relay and C relay and place their contacts at the positions shown by the dotted lines in the figure.
12 → 0 center of relay contact C → make contact of contact C → make contact of SPB relay contact spb → contact sp
7 terminal of l) → No. 5 prong of transformer INDO → No. 4 terminal of transformer INDO → No. 1 terminal of transformer IND2 →
The charge flows through the path from the second terminal of the transformer IND2 to the power supply in the device B, and charges are accumulated in the line capacitance ff1 (OAn) of AB. Here, if the DC resistance value between the transformer IN() and the coils (1-2) is about several ohms, the a pressure at point VA is V
If A(V), then -lv^1) between AB.

Next, when the C relay is restored and the D relay is activated, the C
Since the contact C of the relay is at the position of the solid line and the contact d of the D relay is at the position of the dotted line, the charge accumulated in the AB valley is the capacitance OAB - + S P B IJ Shire spb contact center → spb contact make Contact → D Center of contact d of 17 relay → Make contact of contact d → Resistor R3 → Capacitor CO → 2nd terminal of transformer IND2 → Transformer TN
The discharged charge h-1 is discharged along the path from terminal D201 to capacitor CAH and is stored in capacitor CO. If the voltage at point VB at this time is Vn (V'), capacitor C
The voltage VChn of O is -(!
al).

Here, the value of the capacitance 0λB between A and J3 can be found by comparing the voltage between AB and the voltage between capacitor COO and Ryobiji.

Next, when measuring the line-to-line grouping between DE, find it between A and 8 using the same procedure from the voltage VC (v) at 70 points to the voltage tlT applied between DE, the voltage VI>ry, and the voltage at point VD. Voltage VD (V) to voltage VCD between both terminals of capacitor C1
g is known, and the value of the line capacitance '@CpB between DE can be determined by comparing VDE and VCDB.

The measurement method according to the present invention is detailed above in 1. <As explained above, by using the supply source of one device, the number of leads pulled out from the branch measuring device to the measuring device can be reduced compared to the conventional method, and this has the advantage of reducing the amount of hardware in the lead-in circuit of the measuring device. .

14. Brief description of the drawings FIG. 1 is a diagram for explaining the first embodiment of the method for measuring line constants according to the present invention, and FIG. 2 is a diagram for explaining the second embodiment of the present invention. It is.

■...DC current measuring device RO~R5...Fixed resistance INDo~IND3...Transformer Qo, Qt...Capacitor OAs...AB line capacitance ODD...DEl! 43 Line Capacity Patent Applicant NEC Corporation

Claims (1)

[Claims] By connecting two of the four wires that are drawn into the own device to two transformers, the devices are connected by four wires, and the negative terminal of the power supply is connected to the midpoint of one transformer of one device, and the In the method of measuring the line constant between two devices, power is supplied to the other device by connecting the positive terminal of a power source that has the same potential as the earth to the midpoint of each of the two transformers. Connected 2+f!
A method of measuring line constants that measures the constant of the line between devices by pulling out one wire from each, then drawing out the positive and negative poles of the power supply from one device, and connecting a measuring device between the drawn lines. Measuring method.