JPH03188339A - Continuous monitoring apparatus for abnormal overheating of conductor in closed power distribution panel - Google Patents

Abstract

PURPOSE:To take countermeasure action quickly at the time of abnormal overheating by providing a gas detecting part which detects discharged gas and transduces the value into the electric signal at a ground potential part, and continuously monitoring the abnormal overheating of conductors based on the state of the electric signal. CONSTITUTION:Conductors 2 - 4 are contained in a closed power distribution panel 1. Communi cating gas 21 is discharged into the internal space in the distribution panel 1 from a gas discharging part 20. A gas detecting part 22 detects the communicating gas 21 and transduces the value into the electric signal. A judging circuit 23 judges abnormal overheating. A continu ous monitoring circuit 27 monitors the result of judgment of the judging circuit 23 continuously. These parts are provided. When the conductors 2 - 4 are abnormally overheated exceeding the specified temperature, the communicating gas 21 is discharged in the internal space in the distribution panel 1 from the gas discharging part 20. The detector 22 provided at the ground potential part detects the communicating gas 21 and generates the electric signal. The judging circuit 23 judges the abnormal overheating based on the state of the electric signal. The result of the judgment is monitored at a monitoring station wherein maintenace personnel are always stationed all the time. Therefore, when the abnormal overheating occurs in the conductors 2 - 4, the quick countermeasure action is taken.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for constantly monitoring abnormal overheating of a conductor in a closed switchboard.

[Conventional technology]

As is well known, a closed power distribution board (hereinafter referred to as a power distribution board) consists of a container made of steel plates, which houses electrical equipment such as interconnectors, disconnectors, and transformers, and each electrical equipment is connected with a conductor. ing.

Therefore, this connection part is constructed so that a specified current can be applied by (1) connecting the flat plates together with bolts and nuts, or (2) inserting and connecting them with a plug-in type disconnection part. There is.

Incidentally, these connected portions have higher contact resistance than non-connected portions of the conductor.

Furthermore, after long-term use, contact resistance tends to increase due to loosening of bolts/nuts and springs, dust, etc.

Therefore, even if the energization temperature initially falls within the specified energization temperature range, this range will be exceeded after long-term use. That is, abnormal overheating may occur.

If this abnormal overheating is left untreated, damage to the insulators, reduction in current carrying capacity, etc. will occur, leading to a serious situation in the case of a closed switchboard.

Conventionally, when taking this into consideration, non-reversible thermolabels (those that change color and do not return to their original color when the temperature exceeds a certain temperature) are used at the connection parts of conductors. ), which is well known for its discoloration from white to black. In this case, maintenance personnel will only learn of the abnormal overheating in this area from the discolored thermolabel during periodic inspections and take appropriate action. In reality, not all of the attached thermolabels are visible.

However, this is not always sufficient as it is only dealt with after the fact.

On the other hand, in recent years, from the perspective of improving the reliability of electric power supply, the concept of advance prediction and predictive maintenance has been introduced in this field, and there has been a demand for predicting or preventing accidents.

In response to this, attempts have been made to install an optical fiber between a conductor that is a live part and a ground potential part to detect abnormal overheating of the conductor. However, this device is full-fledged and expensive, and although it may be theoretical, it is impractical.

For example, condensation on the surface can cause insulation problems.

[Problem to be solved by the invention]

Therefore, the present invention aims to provide a practical lid for detecting abnormal overheating of a conductor of a switchboard.

[Means to solve the problem]

In the present invention, a gas discharge part that releases contact gas when a predetermined temperature is exceeded is attached to a conductor, a gas detection part that detects the released gas and converts it into an electric signal is provided in the earth potential part, and the conductor is connected to the conductor based on the state of the electric signal. I am constantly keeping an eye on abnormal overheating.

[Effect]

When the conductor abnormally heats up beyond a predetermined temperature, the communication gas is released from the gas release part into the internal space of the switchboard.

A gas detector provided at the ground potential section senses the communicating gas and generates an electrical signal.

A determination circuit determines abnormal overheating of the conductor based on the state of this electrical signal. The results of this determination are constantly monitored from a monitoring station where maintenance personnel are stationed, so that if abnormal overheating of the conductor occurs, prompt action can be taken.

〔Example〕

This will be explained below with reference to the drawings.

In the iI diagram, 1 is a switchboard, 2 is a bus conductor, 6 is a branch conductor, and 4 is an auxiliary conductor.

5 is a drawer type circuit breaker, and 6 is its input/output conductor.

Reference numeral 7 denotes a push/pull type disconnection connection formed between the input/output conductor 6 and the auxiliary conductor 4.

8 is a fastening connection part between the branch conductor 6 and the auxiliary conductor 4, and the bolt/
It is fastened with a nut 9.

Reference numeral 10 denotes a fastening connection portion between the bus conductor 2 and the branch conductor 3, which are fastened together by bolts and nuts 11.

12 is a front door of the switchboard, and 13 is an internal decorative board of the switchboard.

Reference numeral 20 denotes a gas discharge part installed on the auxiliary conductor 4 near the disconnection connection part 7, that is, at a predicted abnormal overheating site, which generates a communication gas 21 when the disconnection connection part 7 becomes abnormally overheated, in other words, when the temperature exceeds a predetermined temperature. Then, it is released into the internal space of the switchboard, which is a limited space. A gas discharge section 20 is attached to each phase conductor.

Various configurations can be adopted for this gas discharge section 20, but for example, a container may be filled with gas in a manner that is convenient for detection, does not affect the human body, and does not harm the insulating atmosphere of electrical equipment. It is conceivable to uncork the container or crush the container at a predetermined temperature.

Alternatively, a chemical reaction may be caused at a predetermined temperature to generate a predetermined gas, and then the communication gas 21 may be released into the internal space of the switchboard.

In short, it is sufficient that when the temperature of the conductor exceeds a predetermined temperature, the necessary amount of communication gas necessary for detection can be generated and released into the internal space of the switchboard.

It goes without saying that the gas discharge section 20 is installed as close as possible to the disconnection connection section 7, which is a heat source, and that measures are taken to ensure that the generated heat is sufficiently transmitted during installation.

The communicating gas 21 to be released is H2, CO2゜He.
, Co, etc. are used.

The gas detection unit 22 is also selected depending on the type of communication gas 21.

Fastening connection 8.10. A gas discharge section 20 is also installed near the disconnection connection section 7 of the lower stage circuit breaker 5, but a description thereof will be omitted to avoid complication.

Reference numeral 22 denotes a gas detection unit that is provided in common for a plurality of gas discharge units 20, 20, . This is detected and converted into an electrical signal, and this electrical signal S is applied to the line.

23 is an abnormal overheating determination circuit attached to the internal decorative board 16. This determination circuit 26 obtains an electric signal S, and determines that abnormal overheating has occurred somewhere in the conductor since the electric signal S exceeds a predetermined level and continues for a certain period of time.

The determination result by the determination circuit 26 is communicated to the central monitoring board 26 of the monitoring station 25 where the maintenance personnel 24 are permanently stationed. The central monitoring board 26 is provided with an arbitrary type of constant monitoring circuit 27, which constantly monitors the determination results.

It is optional to process the results of constant monitoring in the central processing unit 28 and print them out on a time axis, to issue alarms separately for minor and major failures, and to do other things. Further, the constant monitoring circuit 27 can also be used in combination with that of another device.

In the above-described configuration, gas is not released from the gas release section 20 under normal conditions while the conductor of the switchboard 1 is energized.

Depending on the sensitivity setting, the gas detection section 22 may detect minute gas components in the air and generate some electric signals, but the operating level of the judgment circuit 25 is set so that it functions ignoring this. It is preset in 23a. Of course, this set value may be constantly updated based on the current value if necessary, but the determination circuit 26 may also make the determination based on the rate of change with respect to time.

Next, assume that the disconnection connection section 7 becomes abnormally overheated for some reason. When this overheating exceeds the set temperature of the gas discharge section 20, the gas prepared in advance in the gas discharge section 20 or the gas generated by a chemical reaction is discharged into the internal space of the switchboard 1. .

The inside of the switchboard is separated from the outside by steel plates on all four sides and on the top and bottom, so some air may enter and exit.
They form one limited space.

Therefore, the communication gas 21 is diffused within this space. In the example shown in FIG. 1, when the communication gas 21 reaches the gas detection unit 22 attached to the ceiling plate, it is converted into an electrical signal S.

This electric signal S is applied to the determination circuit 26, and as shown in FIG. 2, it exceeds a predetermined level L. Furthermore, since the communication gas 21 maintains a constant concentration for a while in the interior space of the switchboard 1, the electrical signal S continues for a certain period of time, ie, t1.

The determination unit 26 detects that the electric signal S exceeds the predetermined level L and continues for a predetermined time t as described above, and determines that abnormal overheating has occurred in the conductor.

This determination result is monitored by the constant monitoring circuit 27 of the central monitoring board 26 in the monitoring station 25, and the abnormal overheating is immediately known to the maintenance personnel 24.

Therefore, the maintenance personnel 24 quickly respond to the abnormal overheating by rushing to the site where the switchboard 1 is installed.

[Experimental Example 1] The inventor used hydrogen as the connecting gas 21 and the gas detection unit 22.
Select commercially available hydrogen gas sensors as 4713.
An experiment was conducted inside the switchboard.

The dimension between the gas discharge part 20 and the gas detection part 22 is 1.7 m, and when the temperature of the conductor reaches 120°C, hydrogen gas is released from the gas discharge part, and after 30 seconds, the constant monitoring circuit 27 reports an abnormal overheating state. It was done.

At this time, the communication gas 21 around the gas detection section 22
The concentration was about 20 PPM and this continued for about 3 minutes.

[Experiment example■]

Under the same conditions as in Experimental Example 1, the concentration of the connecting gas 21 around the gas detection section 22 was changed in the direction of decreasing it.

As a result, abnormal overheating was reported by the constant monitoring circuit 27 without any problem up to 2 PPM.

[Modified example]

1. If the judgment circuits 23 of a plurality of switchboards are monitored by one common continuous monitoring circuit 27, the equipment will be inexpensive and it will be extremely practical.

2. When hydrogen is used as the communication gas 21, the gas discharge part 20
A hydrogen storage alloy can also be used as a hydrogen storage alloy.

〔effect〕

According to this invention, there are the following effects.

1. It is possible to constantly monitor abnormal overheating of conductors housed in the switchboard, and take prompt action when abnormal overheating occurs.

2. The gas discharge part attached to the conductor and the gas detection part attached to the non-current part are connected by a connecting gas that is released only when the conductor is abnormally overheated, so insulation in the switchboard must be Therefore, there is no need to make any special design changes to the switchboard.

3. Countermeasures against abnormal overheating do not have to be taken after the fact, as is the case with pasting thermolabels. In addition, overheating can be reliably detected even if overheating occurs at any predicted abnormal overheating location on the conductor, and since it is invisible, there is no problem such as delayed detection leading to serious malfunctions.

4. It does not require a full-fledged device like the one that installs optical fibers, and the structure is simple and inexpensive.

5. Prompt detection and countermeasures for abnormal conductor overheating greatly contributes to improving the reliability of power supply.

& Overall, it is possible to provide a practical constant monitoring device for abnormal overheating of conductors in switchboards.

[Brief explanation of drawings]

FIG. 1 is a route map showing one embodiment of the present invention, and FIG. 2 is a graph for explaining the operation of the determination circuit, where the vertical axis represents the signal level and the horizontal axis represents time. 1: Closed switchboard 2: Bus conductor 3: Branch conductor 5: Draw-out circuit breaker 7: Disconnect connection part 9: Bolt/nut 11: Bolt/nut 13: Internal decorative board 21: Communication gas 23: Abnormal overheating judgment circuit 25: Monitoring station 27: Constant monitoring circuit

Claims (1)

[Scope of Claims] 1. A closed switchboard that houses a conductor to be energized, and a gas discharge part that is attached to a predicted abnormally overheated part of the conductor and releases contact gas into the internal space of the closed switchboard at a predetermined temperature or higher. and a gas detection unit disposed in a non-charged part of the closed switchboard, which detects the communication gas released by the gas discharge unit and converts it into an electrical signal, and the electrical signal generated by the gas detection unit is applied. , a determination circuit that determines whether or not the conductor is abnormally overheated based on whether or not this value exceeds a predetermined value; and a constant circuit that is installed in an electrical station where maintenance personnel are always present and constantly monitors the determination results of the determination circuit. A continuous monitoring device for abnormal overheating of a conductor in a closed switchboard, characterized by comprising a monitoring circuit.