JPH02142313A - Temperature monitoring method at joint of bus duct conductor - Google Patents

Abstract

PURPOSE:To detect abnormal temperature rise easily by connecting thermo- couples having approximately identical temperature-electromotive force characteristic, in series, with joints of bus duct conductors and measuring the total electromotive force of the series circuit. CONSTITUTION:Since the temperature at each joint of conductor is normally maintained at a low level, electromotive force of a series thermo-couple 13 circuit is 0V. Upon occurrence of abnormal temperature rise at any one joint, electromotive force corresponding to temperature rise is induced in the circuit and detected, as a potential difference, through a potentiometer 15. When the electromotive force induced in the circuit is measured continuously through the potentiometer, abnormal temperature rise at joint of conductor can be detected quickly and monitored. By such arrangement, temperatures at many joints of conductors can be monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to a method for monitoring abnormal temperature rises at various conductor connection parts of a bus duct.

(Prior Art) Generally, a bus duct is provided with one conductor connection portion every 3 m, and when the tightening bolts at these conductor connection portions become loose, contact resistance occurs at this portion.

Conventionally, in order to detect abnormal temperature rises at the conductor connections of bus ducts, temperature sensors are installed on the conductors and insulators of each connection, and on the case surface, and the temperature of these parts is measured electrically. Measurements were being carried out.

(Problem to be Solved by the Invention) However, in such a temperature monitoring method, there are many conductor connection parts, and the temperature of each part is measured separately, so many temperature sensors and corresponding receiving instruments, and It required a large number of components, including numerous lead wires to connect each temperature sensor and receiving instrument.

Another problem was that it was difficult to determine whether the absolute value of each temperature measurement value was normal.

The present invention was made to solve these problems, and it does not require many components such as UJ regular lead wires, and it is possible to easily detect abnormal temperature rise without a special judgment device. It is an object of the present invention to provide a method for monitoring the temperature of a bus duct conductor connection section.

[Structure of the Invention (Means for Solving the Problems) The method for monitoring the temperature of a bus duct conductor connection section of the present invention includes attaching thermocouples having substantially equal temperature-electromotive force characteristics to each thermocouple at a plurality of conductor connection sections of a bus duct. The conductor is connected in series so that the electromotive forces of the pair cancel each other out, and the electromotive force of the entire series circuit is measured to detect an abnormal temperature rise at the conductor connection portion.

Thermocouples used in the present invention include copper-constancouple thermocouples, alumel-chromel thermocouples, platinum-rhodium thermocouples, and bismuth-silver thermocouples.

In the present invention, among these thermocouples, thermocouples of the same type are usually attached to each conductor connection part and connected in series so that the electromotive force of each thermocouple is canceled out.

Furthermore, it is desirable that these thermocouples be installed on or near the tightening bolts that tighten each conductor of the bus duct.

In addition, in the present invention, in addition to attaching a plurality of thermocouples for monitoring abnormal temperature rise, a thermocouple may be attached to another adjacent conductor connection part, and the electromotive force at both ends of the thermocouple may be measured with a potentiometer. It is also possible to monitor the absolute value of the temperature of the conductor connection.

(Function) Generally, the electromotive forces e1 and el of each metal wire of a thermocouple made of two types of metal wires are expressed by the following formula. In addition, T2
, T1 are the temperatures at both ends of the thermocouple, respectively.

Since it is this differential voltage that determines UJ in the thermocouple, the electromotive force e is expressed as ee+-el-(K+-2)(T2-T+).

Therefore, as shown in FIG.
If the constantan wires 2 are connected in series, the thermoelectromotive force of each thermocouple will be canceled out, and the electromotive force e of the entire circuit will be: e-61-62=(2 for K1-)(72 wires-72 wires) )
[However, the temperature of the abnormal part for 12 wires] Similarly, when an odd number of wires are connected, as shown in Figure 2,
If the copper wires 1 and the constantan wires 2 are connected to form a series circuit, the electromotive force e of this circuit will be e"el-62" (2 for Kt-) (T2*-71). Note that 3 is a contact point between the copper wire 1 and the constant wire 2 attached to the connection part of the bus duct.

That is, if an even number of thermocouples are connected, the output will be zero, and if an odd number of thermocouples are connected, an electromotive force equivalent to one set of thermocouples will be generated. Here, thermocouple 1 in normal conditions
Since the electromotive force of the group can be made zero by correction,
In either case, if the voltage between the terminals is set to zero under normal conditions, an electromotive force will be generated in this circuit if there is an abnormal temperature rise, so if necessary, if a specified voltage abnormality occurs, An abnormal temperature rise can be detected by operating an alarm device.

(Example) Hereinafter, an example of the temperature monitoring method of a bus duct conductor connection part of the present invention will be described based on the drawings.

In this embodiment, as shown in FIG. 3, an even number of copper-constantan thermocouples 13 are attached to each of a large number of tightening bolts 12 that tighten and connect each conductor 11 of the bus duct. The thermocouples 13 made of the copper wires 13a and the constant wires 13b are connected in series between the lead wires 14 so that the direction of the electromotive force is alternately reversed to form a circuit.

Furthermore, the circuit connecting the thermocouples 13 at both ends includes a potentiometer 1.
5 is inserted, and the electromotive force of the circuit is constantly measured. 16 is a thermocouple consisting of a copper wire 16a and a constant wire 16b for measuring the absolute temperature of a conductor in normal conditions;
17 is a potentiometer that measures the thermoelectromotive force.

In such a temperature monitoring system, in normal times, the temperature of each conductor connection part is kept equally low, so the electromotive force of this circuit in which the thermocouples 13 are connected in series is Ov. However, if an abnormal temperature rise occurs at one conductor connection due to loosening of the tightening bolt 12, etc.
An electromotive force corresponding to the temperature rise is generated in the circuit, and this electromotive force is detected by the potentiometer 15 as a potential difference.

Therefore, by constantly measuring the electromotive force of the circuit with the potentiometer 15, it is possible to quickly detect and monitor the presence or absence of an abnormal temperature rise at the conductor connection portion.

In addition, in the above embodiment, the absolute temperature of the conductor under normal conditions is
Although an example has been described in which one set of thermocouples is attached to a conductor connection part in order to determine ll1lJ, the present invention is not limited to such an embodiment. You can. Furthermore, the number of thermocouples connected in series does not necessarily have to be an even number, and an odd number may be connected in series.

Furthermore, these thermocouples do not need to be connected in series throughout the entire circuit of the bus duct; if necessary, multiple thermocouples can be connected in series to detect abnormalities using the same or separate measurement system for each series circuit. It may also be possible to detect a temperature rise.

[Effects of the Invention] As explained above, according to the method for monitoring the temperature of a bus duct conductor connection portion of the present invention, it is possible to monitor the temperature of a large number of conductor connection portions using a small number of measuring instruments and lead wires.

Further, even without a special judgment device, it is possible to accurately determine whether the temperature is normal or abnormal, and quickly detect the occurrence of an abnormal temperature rise.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining the present invention in detail, and FIG. 3 is a diagram schematically showing an embodiment of the present invention. 1... Conductor 2... Tightening bolt 3.16...
Copper-constantan thermocouple 3a, 16a...Copper wire 3b, 16b...Constantan wire 4...Lead wire 5.17...Potentiometer

Claims (1)

[Claims] (1) Thermocouples with approximately equal temperature-electromotive force characteristics are connected in series to the multiple conductor connections of the bus duct so that the electromotive force of each thermocouple is canceled out, and the electromotive force of the entire series circuit is 1. A method for monitoring temperature of a bus duct conductor connection section, comprising measuring and detecting an abnormal temperature rise in the conductor connection section.