JP2647953B2 - Deterioration judgment method of overhead transmission and distribution line connection body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an overhead distribution line connector for diagnosing deterioration of a connector for connecting an overhead transmission and distribution line (hereinafter simply referred to as an overhead distribution line) in an uninterrupted state. The present invention relates to a deterioration determination method.

[Conventional technology]

Deterioration of a connector for connecting an overhead distribution line such as a bolt-type connector or a vice-type connector causes heat generation, combustion, disconnection, and the like of the electric wire, which adversely affects the reliability of power supply. Therefore, it is necessary to perform the deterioration diagnosis in advance.
A method using an infrared sensor for diagnosing the deterioration of insulators and electric wires has been introduced in a collection of papers at the Joint Conference of the Institute of Electrical and Information Engineers in 1987. This diagnosis method is performed by measuring the surface temperature of an insulator or an electric wire with an infrared sensor and comparing the measured values.

[Problems to be solved by the invention]

However, this diagnosis method cannot be directly applied to the deterioration diagnosis of the connection body of the overhead distribution line. Rust occurs at the wire connection due to water intrusion and heat cycles caused by changes in load current. This increases the contact resistance of the contact. At the same time, the tightening force of the tightening part of the connecting portion is reduced, so that the contact resistance is further increased. Therefore, if the increase in the contact resistance is detected by the infrared sensor, the deterioration diagnosis of the connected body can be performed, but the following problems are considered.

That is, when the method of diagnosing deterioration of the infrared sensor is applied to a connection body of an overhead distribution line, a method of measuring the surface temperatures of many connection bodies and comparing the measured surface temperatures with each other may be considered as one method. In that case, the following problems are assumed.

Since the determination is made with reference to the surface temperatures of a large number of connectors, many measurements are required, and rapid determination cannot be made.

Even if such a determination is made, an erroneous determination is likely to occur because the temperature used as a criterion for determining whether it is sound or deteriorated is not clear.

In general, the load current flowing through the overhead distribution line differs depending on the time zone and the region, and therefore, even if the contact resistance between the connected members is the same, the surface temperature may be different. For this reason, there is a high possibility that the determination will be erroneous in an inter-comparison of only the surface temperature of the connection body. For example, even if the connection body is sound, if the load current is large, the temperature rises, so that erroneous determination may be made as deterioration and accurate determination is difficult.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a determination method capable of accurately determining deterioration of a connected body by a simple operation.

[Means for solving the problem]

In order to achieve the above object, the present invention measures the surface temperature of a connector and the surface temperature of an overhead distribution line connected by the connector, and diagnoses deterioration of the connector based on the temperature difference. .

(Operation)

In the method for determining deterioration of an overhead distribution line according to the present invention, a surface temperature of an insulated wire constituting the overhead distribution line and a surface temperature of a central portion of a connecting body connecting the insulated wire are measured. This measurement is
For example, an infrared sensor is used, and the sensor output is received by a photoelectric element such as a CCD. The electrical signal of the photoelectric element is A / D converted and input to an arithmetic circuit, where a predetermined arithmetic operation is performed. The arithmetic circuit which inputs the surface temperature T _W of the insulated wire and the surface temperature T _J at the center of the connected body performs an operation of ΔT _BC = T _J −T _W , and when ΔT _BC > 0, the connected body deteriorates. It is determined that there is.

〔Example〕

Hereinafter, the method for determining the deterioration of the overhead distribution line connection body of the present invention will be described in detail.

As a connector for an overhead distribution line, there are a compression sleeve, a twisted sleeve, and the like in addition to a bolt type connector, a vice type connector, and the like, and the present invention can be applied to all of them.

FIG. 1 shows a bolt-type connector, and FIGS. 2 and 3 show a connection part by the bolt-type connector. A bolt type connector 1 has a body 3 formed in a side “U” shape and a nut 3
Are screwed together to connect the electric wires 10 and 20. The body 2 has a guide groove 4 formed on an inner surface thereof and a connector guide 5 which moves along the guide groove 4.
Is inserted inside. Then, by lowering the connector guide 5, the conductors of the electric wires 10, 20 inserted into the main body 2
11 and 21 are compressed and connected. The nut 3 maintains this connection by tightening the nut. To perform this tightening, a screw portion 6 is formed on the outer surface of the main body 2. In FIG. 1, reference numeral 7 denotes a nut receiver fixed to the main body 2. When the nut 3 is tightened until it comes into contact with the nut receiver 7, the conductors 11 and 21 are compressed. When the electric wires 11 and 20 are connected using such a bolt-type connector 1, the insulators 11 and 22 are peeled off as shown in FIG.
The conductor 21 is exposed, and the conductors 11 and 21 are inserted into the main body 2 of the connector 1 from right and left. Then, while lowering the connector guide 5, the nuts 3 are tightened so that the conductors 11, 21
Compress. Thereafter, as shown in FIG. 3, the cap 8 is put on the connector 1 and the conductors 11 and 21, and in this state, the insulating tape 9 is wrapped to complete the connection operation. In this case, an adhesive polyethylene tape can be used as the insulating tape 9, and the tape 9 is carefully wound twice or more with a half wrap, and its thickness is set to, for example, 2 mm.

The present invention measures the surface temperature of such a connection body and the surface temperature of an electric wire, and judges the deterioration of the connection body from the temperature difference. Deterioration of the connection body appears as an increase in contact resistance due to rusting due to the intrusion of water and an increase in contact resistance due to a decrease in the tightening force of a tightening member such as a nut. Surface temperature rises. On the other hand, since the electric wires do not generate such heat, a difference occurs in the surface temperature. Here, as the temperature measurement site in the electric wire, a site with a distance that is not affected by the heat generation of the connection body is appropriately selected.

FIG. 4 shows the results of connecting the electric wires 10 and 20 using the bolt type connector 1 as a connection body and measuring the surface temperature of the electric wires 10 and 20 with an infrared sensor. The characteristic curve B shows a healthy product in which the nut was tightened at 500 kg, with a deteriorated product having a resistance larger than the specified value. From the comparison results of these characteristic curves A and B, it can be determined as follows.

In the case of a sound connection body, the surface temperature distribution of the connection body and the electric wire has a distribution with peaks P ₁ and P ₂ at both ends of the connection body, and the central part P of the connection body
_C is lower than the temperature of the electric wire in a portion not affected by the heat generation of the connection body. (ΔT _BC <0).

Table salt temperature of the center portion P _C when connection of the contact resistance is large connector (degraded connection member) is higher than the other portions, the maximum value. In particular, the difference from the surface temperature of the electric wire in a portion away from the connector and not affected by heat generation becomes large (ΔT _BC > 0).

Therefore, the surface temperature rise due to deterioration central portion P _C is the largest of the connector 1, it indicates the maximum surface temperature, by obtaining the difference [Delta] T _BC of the surface temperature of the surface temperature and the electric wire, the [Delta] T _BC> 0 In that case, the deterioration can be determined. The same applies to the vice connector, and the deterioration can be determined by measuring the surface temperature of the central portion of the connector and the surface temperature of the electric wire. On the other hand, when the connection body is a compression sleeve or a twisted sleeve, the connection length of the conductor is several tens of cm, and the maximum surface temperature does not always appear at the center. Therefore, in the case of these sleeves, the surface temperature in the length direction of the sleeve excluding the surface temperature of both ends of the sleeve (corresponding to P ₁ and P ₂ ) is measured at appropriate intervals, and the maximum value and the electric wire The determination can be made by calculating the difference between the surface temperatures.

FIG. 5 shows the above Δ
The relationship between _TBC and contact resistance is plotted, using a bolt-type connector as the connector and 6600 V, 60 mm
Uses ² polyethylene insulated wires. 10 ^-5 to 10 ^-4
As shown by a point A, ΔT _BC is equal to or less than zero degree even with a load current of 230 A in a healthy connection having a contact resistance of On the other hand, in the case of the deteriorated connection body, ΔT _BC changes depending on the contact resistance and the load current. For example, as shown by points C and D, it is equal to or higher than zero degree, and ΔT _BC
> 0 can be used as a criterion for determining deterioration. Where C,
D is a plot of the values in Table 1 described below.

In addition, in the actual distribution line, the surface temperature of the connection body and the electric wire changes depending on environmental conditions such as wind and outside temperature. According to the present invention, in order to compare the surface temperatures under the same environment,
These effects can be eliminated.

 Hereinafter, a more specific description will be given.

The surface temperature of the connection body and the electric wire was measured by an infrared sensor at 186 connection points of the actual distribution line where a polyethylene insulated electric wire for outdoor use having a voltage of 6600 V and a cross-sectional area of 60 mm ² was connected by a bolt-type connector. And from the measured value ΔT _BC
As a result, two connection portions where ΔT _BC was larger than zero were detected. After measuring the load current for these two locations, remove the load current from the actual distribution line and load it in the laboratory.
_BC and contact resistance were measured. The results are shown in Table 1 and plotted as points C and D in FIG. 2 as described above. The removed deteriorated product was in agreement with the result measured in the laboratory, and it was confirmed that the connection body had been deteriorated.

[Effect of the Invention] As described above, the present invention relates to the surface temperature of the connection body,
Since the deterioration of the connector is determined based on the difference from the surface temperature of the electric wire, the determination of each connector can be performed, and the determination can be performed simply and accurately. For this reason, it is possible to detect the deterioration of the connection body at an early stage, to improve the efficiency of maintenance and management work of the overhead transmission and distribution line, and to improve the reliability of power supply.

[Brief description of the drawings]

FIG. 1 is a front view showing a bolt type connector, FIGS. 2 and 3 are side views showing connection examples, FIG. 4 is a characteristic diagram showing surface temperature in a bolt type connector, and FIG. FIG. 4 is a characteristic diagram in which the relationship of _BC is plotted using load current as a parameter. DESCRIPTION OF SYMBOLS 1... Bolt type connector 2... Body 3... Nut 4... Guide groove 5. Connector guide 6. Screw part 7 nut receiver 8 case 9 insulating tape 10, 20 ... electric wires 21, 22 ... conductor, 12, 22 ... ... insulator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuya Takahashi 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside the Electric Wire Research Laboratory, Hitachi Cable Co., Ltd. (72) Kenichiro Soma Hidaka-cho, Hitachi City, Ibaraki Prefecture 5-1-1, Nippon Electric Wire & Cable Co., Ltd. (72) Inventor Teruo Yoshimoto 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Pref. Nippon Electric Wire & Cable Co., Ltd. (56) References Akira Mikai 58-56957 (JP, U) Shikoku Electric Power Co., Inc. Research Report, [49] (1987) 68-87 Electric Calculation, 55 [2] (1987) P.E. 55− 59

Claims (2)

(57) [Claims] The present invention is characterized in that the surface temperature of a connecting body for interconnecting overhead transmission and distribution lines and the surface temperature of the overhead transmission and distribution line are measured, and the deterioration of the connecting body is diagnosed based on a difference between the surface temperatures. A method for determining the deterioration of an overhead transmission / distribution line connection body. 2. The connector according to claim 1, wherein the surface temperature of the connector is a surface temperature at a central portion of the connector, and when the surface temperature is higher than the surface temperature of the overhead power transmission line, it is determined that the connector has deteriorated. 2. The method for judging deterioration of an overhead transmission / distribution line connection body according to claim 1.