JP3053470B2 - Apparatus and method for sampling gas in joint box of prefabricated joint for CV cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for sampling gas in a joint box of a prefabricated joint for a CV cable and a sampling method using the apparatus. when discharge is generated, collected decomposition gas generated in the joint box
It is something that can be done.

[0002]

2. Description of the Related Art Insulators for high-voltage equipment used in electric power equipment are required to have good insulation properties and to be excellent in economy, workability, and mechanical strength, and various organic polymer materials are used. . The quality of solid organic polymer insulating materials has been improved by improving manufacturing processes.However, as for long-term reliability, such as life expectancy from the start of equipment operation to the time of dielectric breakdown, the cause of the long-term reliability must be clarified and measured. -Many problems remain, such as the establishment of evaluation techniques. Internal partial discharge, which is one of the causes of insulation deterioration, is a weak discharge that repeatedly occurs in pulses in voids caused by vaporization of residual volatile components during formation of solid insulating material and separation from conductor parts. , Its detection is very difficult. If the insulator continues to be exposed to the internal discharge, the erosion of the insulator surface facing the void proceeds without being detected from the outside, and after the occurrence of the dendritic fracture path, the solid part suddenly breaks down the entire path.

[0003] Deterioration of the insulator due to internal partial discharge is considered to be mainly caused by oxidation of the insulator surface by active species such as atomic oxygen generated by the discharge in the void.
Details have not yet been elucidated. Therefore, the detection of the internal partial discharge and the elucidation of the insulation deterioration mechanism due to the internal discharge have become major issues in high-voltage equipment design and maintenance technology. The nature of the deterioration is the alteration of the insulator surface, and it is necessary to pay attention to the chemical reaction occurring in the void and on the insulator surface to know the mechanism. It is thought that their elucidation can be a powerful means of developing insulating materials having high partial discharge resistance. When a partial discharge occurs in the void, the surface of the insulator is oxidized by active substances such as atomic oxygen generated by the discharge, and the insulator is gradually decomposed, thereby decomposing carbon monoxide, carbon dioxide, hydrogen, etc. It is known that gas is generated. Since this decomposed gas diffuses into the outside air, it is difficult to measure the change over time of the decomposed gas,
Since the decomposition gas does not mix with the outside air in the joint box, the progress of the chemical reaction in the void and on the insulator surface is inferred by measuring the change over time in the composition of the gas generated in the joint box. I can do it. However, for the above purpose,
There is no example of analyzing the gas in the joint box of the prefabricated joint for V cable.

As a method of analyzing the gas in the joint box, a method of installing a gas detection tube such as a commercially available CO sensor may be considered. However, these sensors have low detection sensitivity, and are, for example, insulative materials such as H _{2 of} ppb order. If the decomposition gas is very small, it cannot be detected. Further, since the life of the sensor and the like are often unknown, it is necessary to check the life of the sensor and the like in advance in order to put the sensor into practical use. In a sampling method actually performed by an oil insulation transformer or the like, an insulating oil is sampled by a syringe, and a gas contained in the oil is analyzed by a gas chromatograph. When sampling the gas in such a way syringe, it may cause problems such as leakage at the input of the syringe for H ₂ is particularly light gas. It is also known that oxygen is consumed by oxidation due to discharge.However, if the syringe is left in the air after sampling the insulating oil, air may be mixed into the syringe, There is a problem with the credibility of the results obtained. Alternatively, the method of directly attaching an analyzer such as a gas chromatograph to the prefabricated joint is high in sensitivity, but if the price of the analyzer is expensive and the amount of argon gas filled in the carrier gas pressure tank becomes large, the inside of the sinus canal will be increased. However, it is not practical from the viewpoint of maintenance due to the possibility of lack of oxygen.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a prefabricated CV cable for a CV cable in which gas in a joint box is easily sampled by an economical and safe method and the result obtained by this method is reliable. It is an object of the present invention to provide an apparatus and a method for sampling gas in a joint box of a joint.

[0006]

In order to achieve the above object, such a problem is to take the joint box of prefabricated joint for CV cable
The attached gas sampling connector and this gas
Sun that can be detachably attached to the sampling connector
And a gas sampling connector.
Take-out pipe communicating with the joint box and this
A valve that opens and closes the discharge pipe, and a branch from the discharge pipe,
A branch pipe connected to the evacuation system and a bar for opening and closing the branch pipe;
And a connection port at the tip of the take-out tube.
The pulling tube has a valve at each end,
Gas sampling at the end outside the first valve
Connected to the connector port of the
The problem is solved by a method of introducing a gas in a joint box into a sampling pipe by using a pulling apparatus and a pressure difference between a gas in the joint box and a gas in the sampling pipe using the apparatus . Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a sampling apparatus according to the present invention. In the drawing, reference numeral 1 denotes a joint box of a prefabricated joint for a CV cable.
Inside, a CV cable (not shown) is connected.
The joint box 1 is provided with a gas sampling connector 2.

The connector 2 has a take-out pipe 3 for introducing gas in the joint box 1, a connection port 4 for introducing gas introduced into the connector to another pipe, and a branch pipe connected to a vacuum pump. 5 is comprised. In addition, the take-out pipe 3 and the branch pipe 5 have a valve 6 corresponding to a high vacuum,
When the valves 6 and 7 are closed, gas cannot enter or exit.

[0010] A sampling pipe 8 is attached to the connection port 4 of the connector 2, and the gas in the joint box 1 introduced into the connector 2 is supplied to the sampling pipe 8.
It can be introduced inside. High vacuum compatible valves 9 and 10 are provided at both ends of the sampling tube 8, and when the valves 9 and 10 are closed, gas cannot enter or exit. The sampling tube 8 has a structure compatible with high vacuum and is made of a stainless steel tube.
Furthermore, the inner surface is glass-coated to prevent a reaction in the tube with the introduced gas in the joint box.

Next, a method of collecting gas in the joint box into the sampling pipe 8 using such a device will be described. First, before sampling, the valves 6 and 7 are closed before the connector 2 is installed in the joint box 1 so that one gas or outside air in the joint box cannot enter the connector 2. Then, interior ^10-2 2-10 of previously sampled tube 8
^After evacuating to about ^-3 torr and closing valves 9 and 10, attach to connector 2. After this, valve 6
The opening, after evacuation at connecting a vacuum pump 10 ^{over 2-10 -3} torr about the branch pipe 5, when closing the valve 6 in the connector 2 is surrounded by the valve 6, 7, 9 and the sampling tube is vacuum State. When the valves 7 and 9 are opened while the valves 6 and 10 are closed, gas pressure in the joint box 1 and the connector 2 and the sampling pipe 8 cause gas pressure in the joint box 1 and the connector 2 and the connector 2, respectively. It can be introduced into the sampling tube 8. Thereafter, when the valve 9 is closed, the gas in the joint box 1 can be collected in the sampling pipe 8.

The gas in the joint box 1 collected in the sampling tube 8 in this way is analyzed by the gas chromatograph 11 using, for example, a gas sampler as shown in FIG. First, the sampling tube 8 filled with the gas in the joint box 1 is detached from the connector 2 and then connected to the hexagonal cock 12 connected to the gas chromatograph 11. This hexagonal cock 12 is 13, 1
There are 4, 15, 16, 17, and 18 ports, as shown by the solid line in advance, between 13-14, 15-18, 1
The six-way cock 12 is set so that the gas flows between 6 and 17, and thereafter, between the valve 9 and the port 15 of the sampling pipe 8, and between the valve 10 and the port 1 of the sampling pipe 8.
It is connected so that the gas flows between the six spaces. The six-way cock 12 has a vacuum pump 19 connected to the ports 17 and 18.
Is to be evacuated.

Next, a method for introducing the gas in the joint box 1 collected in the sampling pipe 8 into the gas chromatograph will be described. While the valves 9 and 10 of the sampling tube 8 are closed, ports 17 and 18 are operated by the vacuum pump 19.
After further evacuation, when the hexagonal cock 12 is set so as to close the ports 17 and 18, between 18-15-9,
The space between 17-16-10 is in a vacuum state. At this time, the carrier gas flow control device 20
More carrier gas is flowing. Then, as shown by the dotted line in FIG.
6-way cock 12 so that gas passes between 6 and 17-18
Is set, and when the valves 9 and 10 are opened, the carrier gas flows from the carrier gas flow controller 20 to 13-16-10-.
Since the gas flows into the gas chromatograph 11 through the path of 9-15-14, the gas in the joint box 1 filled between 9 and 10 of the sampling tube 8 is carried on the carrier gas to the column in the gas chromatograph 11. be introduced. The filler in the column in the gas chromatograph 11 is hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, nitrous oxide, methane,
Those that can detect ethylene, ethane, acetylene, etc. are used. In the analysis by the gas chromatograph 11, the volume% of each gas in the joint box 1 can be quantitatively detected. The sampling tube 8 from which the gas in the joint box 1 has been collected is analyzed not only by the gas chromatograph 11 but also by attaching it to a quadrupole mass spectrometer or the like to measure trace gas components that cannot be detected by the gas chromatograph 11 alone. It is possible to

[0012]

As described above, the sampler of the present invention
According to a pre-fabricated device and method, a prefabricated CV cable
The gas in the joint box of the joint is
Without contamination or leakage of the gas
Can be collected in a tube. In addition, the gas was collected and stored.
Remove the sampling tube from the gas sampling connector
And bring it to an analytical room for analysis.
Analysis work is not required, and in good condition
Highly accurate analysis can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an apparatus used for a method of sampling gas in a joint box of a prefabricated joint for a CV cable according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a gas sampler for analyzing gas in a joint box collected in a sampling tube according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Joint box, 2 ... Connector, 8 ... Sampling tube

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinji Umeda 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Masaru Kurata 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire (56) References JP-A-63-98541 (JP, A) JP-A-1-2093982 (JP, A) JP-A-2-12057 (JP, A) JP-A-1-26151 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 1/22

Claims (2)

(57) [Claims] 1. A gas sampling device attached to a joint box of a prefabricated joint for a CV cable .
Connector and this gas sampling connector
The gas sampling connector is attached to the joint box.
An outlet tube that communicates with a valve that opens and closes the outlet tube
Branch from the outlet pipe and connected to the vacuum exhaust system.
Branch pipe, a valve to open and close this branch pipe, and a take-out pipe.
The sampling pipe has a valve at each end.
And a gas sump at the end outside one of the valves
It is connected to the connection port of the ring connector.
Prefabricated joint for CV cable
Gas sampling device in the joint box. 2. Use of the sampling device according to claim 1.
Gas pressure in the joint box and sampling tube
Using the force difference, joint box inside sampling pipe
CV cable plug characterized by introducing gas inside
Gas sump in joint box of Rehab joint
Ring method.