JPH07123331B2 - Conductive part overheat detection notification method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive part overheat detection and notification method for detecting and reporting the occurrence of abnormal overheat of a conductive part such as a connection part of electric power equipment.

[0002]

2. Description of the Related Art Conventionally, in power equipment such as power receiving and transforming equipment, the temperature of a conductive portion such as a connecting portion and a contact portion of a main circuit portion thereof exponentially rises due to a sudden abnormality and an aged abnormality, During energization, a state of abnormal overheating that exceeds the normal temperature rise may occur locally.

In order to detect the occurrence of this abnormal overheat, conventionally, a thermo label is provided on the conductive part or a thermo paint is applied, and the thermo is detected by, for example, a regular inspection about once a month. The label and thermo paint are visually inspected for discoloration and checked for any abnormalities.

[0004]

When detecting the occurrence of abnormal overheat by visual inspection as in the prior art, there is a problem in that it requires a regular inspection by an operator and labor is not saved. It will be detected based on the change and experience of the worker, and since it is difficult to perform frequent inspections, early detection cannot be performed, and detection of sudden abnormal overheating due to sudden abnormality is delayed. There is also a problem that is likely to occur. In addition, it is difficult to quantitatively grasp the overheating state,
In addition, for complicated structures that do not approach the conductive part to be detected due to obstacles such as other members in the device,
In some cases, visual inspection is difficult and cannot be detected.

When the conductive part of this kind is housed in a case such as a gas insulated switchgear (GIS), the temperature of the conductive part exponentially rises due to abnormal overheating of the conductive part, and the installation thereof is performed. The gas temperature and gas pressure of the environment also increase exponentially.

The present invention uses a comparatively simple detection and calculation process that uses the periodic detection result of the temperature of the conductive part or the gas temperature or gas pressure of the installation environment of the conductive part. The purpose is to detect and report the occurrence of abnormal overheating, and also to predict when dangerous conditions will continue to occur.

[0007]

In order to achieve the above object, in the method for detecting and notifying overheating of a conductive portion of the present invention, the temperature of the conductive portion, the gas temperature of the environment in which the conductive portion is installed, the gas pressure, etc. The detected amount is detected cyclically to detect the time when the detected amount reaches each of the plurality of levels of attention amount, and each coefficient of the time-function formula of the detected amount is determined from the constant determination calculation based on each detection time. , The determined value of each coefficient is substituted into the time function formula to calculate the dangerous amount arrival time, and when the detected amount reaches the caution amount in the final stage, the occurrence of the abnormal overheat and the arrival of the dangerous amount. Notify the time.

[0008]

In the case of the conductive portion overheat detection and notification method of the present invention configured as described above, changes in the temperature of the conductive portion, the gas temperature of the installation environment of the conductive portion, and the gas pressure due to abnormal overheating are expressed by exponential functions of time. Focusing on what is shown, the temperature or gas temperature or gas pressure of the conductive part is used as the detected amount, and the time at which this detected amount reaches the set attention level in multiple stages is detected, and simultaneous equations using these detected times are detected. Etc., the respective constants of the above function formula are determined. Further, each determined constant value is substituted into the functional expression to detect the time when the detected amount reaches the set dangerous amount, and the notification of the occurrence of abnormal overheat and the prediction of the dangerous amount arrival time are performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described with reference to FIGS. In this embodiment, as shown in FIG. 2, for example, the connecting portion of the conductors 1 and 2 of the main circuit portion of the GIS is used as the conductive portion 3 to be detected.

The conductive portion 3 is provided on the support insulator 4,
Non-contact type conductive part temperature sensor with upper radiation thermometer 5
Thus, the temperature is detected as a detected amount in a non-contact manner. The cable 6 of the temperature sensor 5 is connected to the sensor input section 8 of the conductive section overheat detection and notification device 7 of the computer configuration of the monitoring panel shown in FIG. 1, and the analog signal of the temperature detected by the sensor 5 is transmitted to the input section 8. It

Further, the signal of the input section 8 is converted into digital data by the A / D converter 9 at a predetermined sampling cycle and sent to the arithmetic processing section 10 formed by the CPU.
Then, the arithmetic processing unit 10 detects abnormal overheat described later,
When the prediction process is executed and the temperature of the conductive part 3 reaches the final caution temperature, the overheat detection output part 11 is notified of the timing of occurrence and the dangerous temperature, and the output part 11 notifies the outside of the device. Supplies contact signals for alarms to devices.

Next, the temperature change characteristics of the conductive portion 3 and the detection and prediction of abnormal overheating will be described. A Temperature Change Due to Normal Current Energization The temperature of the conductive portion 3 rises and changes according to an exponential function due to Joule heat generation due to current energization, as shown by the solid line a in FIG. ℃)
Has the relationship of the following expression 1 with respect to the subsequent elapsed time t (H).

[0013]

[Formula 1] Δθ = Δθ _m · {1-exp (-t / T)}

In the equation (1), Δθ _m is the temperature rise saturation value (° C.) and T is the thermal time constant, which is determined by the heat conduction and heat dissipation characteristics with respect to the heating energy amount at that time.

B Detection of Abnormal Overheated State and Prediction of Time to Reach Dangerous Temperature When the Joule heat amount increases in the conductive portion 3 due to increase in resistance value due to loosening of mounting bolts or poor contact pressure state, the temperature is solid line b in FIG. As shown in, the temperature rises abnormally, and overheating occurs that reaches the dangerous temperature θ _max due to continued use. At this time, the temperature θ of the conductive portion 3 based on the applied current is
The following exponential function of Equation 2 raises and changes.

[0016]

[Equation 2] θ = Δθ _m · [1-exp {− (t−t ₀ ) / T}] + θ ₀

In the equation (2), t ₀ indicates the time when abnormal overheating starts, and t> t ₀ . θ ₀ is the temperature at t ₀ . Then, when estimating the time t _{ma x} to reach the critical temperature theta _max detects the occurrence of overheat, careful temperature theta ₁ of a plurality of _{stages, θ 2, ..., θ n} (θ 0 <θ 1 ...
<Have set up θ _n <θ _max), detects the time t ₁ ~t _n reach temperatures theta ₁ through? _N, the coefficient of non-linear function using the time t ₁ ~t _n (non-linear regression parameters ) Or the simultaneous equations of the following equation 3, the coefficients Δθ _m , T, t ₀ , θ ₀ in the equation 2 can be determined.

[0018]

[Equation 3] θ ₁ = Δθ _m · [1-exp {− (t ₁ −t ₀ ) / T}] + θ ₀ θ ₂ = Δθ _m · [1-exp {− (t ₂ −t ₀ ) / T }] _{+ θ 0:::::} ::: θ n = Δθ m · _{[1-exp {- (t n} -t 0) / T} ] + theta ₀

Further, each determined coefficient Δθ _m , T,
By substituting t ₀ and θ ₀ into the equation of Equation 2 and modifying them, it is possible to calculate and predict the time t _{max at} which the dangerous temperature θ _max is reached (the dangerous amount arrival time) by calculating the time function equation of the following Equation 4.

[0020]

## _EQU00004 ## t _max = t ₀ −T · Ln {1- (θ _max −θ ₀ ) / Δθ _m }

In the equation (4), Ln is an operator showing a natural logarithm. Then, the final attention temperature θ _n
Is the detection temperature for the occurrence of abnormal overheating, the detection and prediction of time t _max can be _notified when this temperature θ _n is reached. Therefore, the arithmetic processing unit 10 executes the process of detecting and predicting abnormal overheat shown in FIG.

Each time the data of the detected temperature θ is supplied from the A / D converter 9, the detected temperature θ is compared with the caution temperatures θ _{1 to} θ _{n at} each stage, and the detected temperature θ is the caution temperature θ. ₁ ~
detects the time t ₁ ~t _n reaching theta _n held in a memory or the like. Furthermore, when the time t _n is detected, for example, the equation 3
Each coefficient Δθ _m ,
Determine T, t ₀ , θ ₀ .

Then, the determined values of the respective coefficients Δθ _m , T, t ₀ , and θ ₀ are substituted into the equation (4) to calculate the dangerous amount reaching time t _max , and the occurrence of abnormal overheating and the time t _max are output. Notify 11 Note that the sampling cycle of the detected temperature θ is set to, for example, 1 / 6H (10 minutes) in order to enable early detection of sudden abnormal overheating based on a sudden abnormality.

Therefore, based on the temperature measured by the temperature sensor 5, the occurrence of abnormal overheat and the time when the temperature reaches the dangerous temperature are automatically detected and informed, and a great labor saving can be achieved. Moreover, since it is only necessary to measure the temperature of the conductive portion 3 and it is not necessary to measure the energizing current or the like, the sensor configuration is simplified and the arithmetic processing of the arithmetic processing unit 10 is also simplified, and the simple and inexpensive configuration facilitates quick operation. It can detect and predict.

Based on the setting of the sampling cycle of the detected temperature θ, the detection interval of occurrence can be made extremely shorter than that in the conventional visual inspection, and the occurrence of sudden abnormal overheating due to sudden abnormality can be detected at an early stage. Can be notified. Further, since the temperature sensor 5 may be installed in advance, it is possible to easily detect even a conductive portion that is not easily approached by an obstacle without any inconvenience.

The temperature sensor of the conductive portion 3 may be any of an analog output type, a contact output type, a contact type bimetal type, or a type using a shape memory alloy.

Further, the number and value of the caution temperatures θ _{1 to} θ _n may be set according to usage conditions and the like.

In the above embodiment, the temperature of the conductive portion is used as the detected amount. However, for example, when the conductive portion is housed in the housing of the GIS or the like, the temperature rise of the conductive portion is tracked and the environment Since the gas temperature and the gas pressure also change, it is of course possible to notify the occurrence of abnormal overheating of the conductive portion and predict the dangerous amount reaching time by using the detected amount as the gas temperature and the gas pressure in the same manner as in the above embodiment. is there.

[0029]

Since the present invention is configured as described above, it has the following effects. The times t _{1 to} t _{n at} which the detected amount θ consisting of the temperature of the conductive portion 3 or the gas temperature or gas pressure of the installation environment due to abnormal overheating of the conductive portion 3 reaches the set attention amount θ _{1 to} θ _n Detecting, determining each coefficient of the time functional expression of the detected amount from each detection time t _{1 to} t _n , substituting the determined value of each coefficient into the functional expression, calculating the dangerous amount arrival time t _max , and finally Attention level θ
_{When n} is reached, the occurrence of abnormal overheat is notified and the dangerous time arrival time t _max is predicted, so that the temperature or gas pressure can be measured without visually checking the discoloration of the conventional thermo label or thermo paint of the conductive part. It is possible to detect and report the occurrence of abnormal overheat with a simple method suitable for automation by comparison detection and prediction calculation based on the measurement of, and to predict when dangerous temperature will be reached, and to save manpower. It is possible to improve safety and the like.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a conductive part overheat detection and notification method of the present invention.

FIG. 2 is a schematic diagram of a conductive portion to be detected.

FIG. 3 is a temperature characteristic diagram of a conductive portion based on an energized current.

FIG. 4 is a temperature characteristic diagram when abnormal overheating occurs.

FIG. 5 is a flowchart for explaining processing of the arithmetic processing unit.

[Explanation of symbols]

3 Conductive part 5 Conductive part temperature sensor 7 Conductive part overheat detection notification device θ _{1 to} θ _n Caution temperature θ _max Dangerous temperature

Claims (1)

[Claims] 1. A detected amount such as a temperature of a conductive part such as a connection part of a power device, which exponentially rises in temperature due to occurrence of abnormal overheating, a gas temperature of an installation environment of the conductive part, a gas pressure, etc., is periodically measured. Detecting and detecting the time at which the detected amount reaches each of a plurality of levels of attention amount, determining each coefficient of the time function formula of the detected amount from a constant determination calculation based on each detection time, and determining each coefficient Calculate a dangerous amount arrival time by substituting a value into the time function formula, and notify the occurrence of the abnormal overheat and the dangerous amount arrival time when the detected amount reaches the caution amount in the final stage. A method for notifying the detection of overheating of a conductive part.