JPS63117274A - Internal abnormality detector for gas sealed type electric apparatus - Google Patents

Abstract

PURPOSE:To enable the detection of internal abnormality positively, by providing a shut-off valve controller to close the shut-off valve receiving an opening- closing operation signal during the opening or closing operation of an electric circuit switch and open the shut-off valve after a specified time. CONSTITUTION:A shut-off valve 16 is kept open during the normal operation in which a rated voltage is applied with an electric circuit switch closed and internal abnormality is detected by keeping an SF6 gas 8 containing an SF6 decomposed gas in contact with a sensitive element 9. Then, the SF6 decomposed gas is generated by an arc discharge to be diffused into a closed container 1 during the opening operation of the electric circuit switch, making the density of the SF6 decomposed gas rise sharply near the element 9 and hence, an opening-closing operation signal is sent to the valve 16 through a shut-off valve controller 18 from an operation switch 20 of a circuit switch control panel 14 to close the valve 16. After a specified time, a signal for opening the valve 16 is sent from the controller 18 to open the valve 16 and the gas 8 gets in contact with the element 9 to detect internal abnormality. Thus, an internal abnormality can be detected positively.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is an SF, non-standard method for determining the presence or absence of an internal abnormality in gas-filled sealed electrical equipment, particularly equipment having a circuit breaker such as a cross-sectional view of a circuit breaker. This invention relates to an internal abnormality detection device using a reversible characteristic sensing element.

[Conventional technology]

Figures 8 and 9 are a sectional view and an enlarged view of the main parts of a conventional internal abnormality detection device for gas-sealed electrical equipment, as disclosed in, for example, Japanese Patent Publication No. 57-36817 and Utility Model Application Publication No. 61-40657. In the figure, (1) is a sealed container, inside which is SF.

A circuit breaker (2) filled with gas (8) is arranged, and the circuit breaker (2) is connected to a movable contact (3), a fixed contact (4), a spacer (5), a high voltage conductor (6), etc. The movable contactor (3) is moved in response to the opening/closing operation signal from the circuit breaker control panel (14) to open/close the electric circuit.

Movable contact (3) and fixed contact (4) of circuit breaker (2)
).

High voltage is applied to the electrical circuit parts such as the high voltage conductor (6), and if an internal abnormality such as discharge or local heating occurs in this electrical circuit part, the enclosed SF and gas (8) will be decomposed. sulfur tetrafluoride (SF4) thyronyl fluoride (SOFz),
It generates active SF such as hydrogen fluoride (I(F)) and decomposed gas, which also moves throughout the sealed container (1) by diffusion and convection and has a negative impact on others.Please note that the sealed container (1)
An adsorbent (not shown) that adsorbs and removes SF and decomposed gas by contacting them is provided inside to actively reduce the SF and decomposed gas.

In addition, a sensing element (9) having an irreversible property that its electrical resistance value decreases when it comes into contact with SF or decomposition gas is attached to the flange (7) inside the sealed container (1), and the sensor element is sealed via the lead wire (10). The container (1) is electrically connected to an external device. (11) is a resistance measuring device, which measures the electrical resistance value of the sensing element (9) through the lead wire (lO).

(12) is a level detector, which determines whether the value measured by the resistance measuring device (11) has reached a preset level. (13) is an indicator, and a level detector (
12), when the set level is exceeded, it is assumed that an internal abnormality has occurred, and an alarm is displayed as a result of the judgment.

[Problem that the invention seeks to solve]

The conventional internal abnormality detection device for gas-filled sealed electrical equipment is
Because of the above structure, for example, in devices that have electrical circuit switching parts such as disconnectors and circuit breakers, there is a very short time between the movable contact and the fixed contact even during normal switching operations. However, an arc discharge phenomenon occurs and a considerable amount of SF occurs.
Decomposition gas is generated, and with the addition of stirring action due to the movement of the movable contactor, SF and decomposition gas expand throughout the entire area inside the sealed container.
It also reaches the vicinity of the bare sensing element. Therefore, this sensing element works not only when there is an internal abnormality, which is its original purpose, but also during normal opening/closing operations by reducing the resistance value.
"Normal" was mistakenly judged as "Abnormal", and since the sensing element has irreversible characteristics, once the resistance value has dropped, it will not return to a high resistance value again, so it will no longer be usable, and the deteriorated sensing element must be replaced. There were problems such as having to do it.

This invention was made to solve the above-mentioned problems. During normal opening and closing operations, arc discharge causes SF,
The purpose of this invention is to effectively detect internal abnormalities in electrical equipment that has electrical circuit opening/closing parts that generate decomposed gas.

[Means for solving problems]

The internal abnormality detection device for gas-filled sealed electrical equipment according to the present invention surrounds the SF6 decomposition gas sensing element with a shielding part that shields it from the SFa gas atmosphere, and a part of the shielding part is provided with an SPi gas intake port having an on-off valve. The electric circuit switch is equipped with an on-off valve controller that closes the on-off valve in response to an on-off operation signal when the circuit switch is opened or closed, and opens the on-off valve after a predetermined period of time.

In addition, in the internal abnormality detection device for gas-filled sealed electrical equipment according to another invention of the present invention, the sensing element is set using the decrease curve of the SFb decomposed gas concentration due to the adsorbent, which is acquired and input in advance in the actual equipment. Equipped with a time calculator that calculates and outputs the closing time of the on-off valve from the input sensitivity level and the amount of arc energy obtained by receiving a current signal proportional to the current of the circuit breaker, and can open or close the circuit breaker. The device is equipped with an on-off valve controller that closes the on-off valve in response to an on-off operation signal from the electric circuit breaker, and opens the on-off valve after the time calculated and output by a time calculator.

[Effect]

In this invention, since the on-off valve is open during normal operation of the circuit breaker, the sensing element comes into contact with the SF and gas atmosphere inside the sealed container and detects an internal abnormality. By switching the valve from open to closed and shielding the sensing element from the SFa gas atmosphere inside the sealed container, erroneous determination of internal abnormality due to SF and decomposition gas generated by arc discharge that occurs during normal opening and closing operations of the circuit breaker is prevented. ” and “performance deterioration of the irreversible characteristic sensing element” for a predetermined period of time, the on-off valve is switched from closed to open and internal abnormality is detected again.

In another aspect of the present invention, the amount of SF and decomposed gas generated by arc discharge that occurs during normal opening and closing operations of a circuit breaker is determined from the amount of arc energy, and the concentration of SF and decomposed gas due to the adsorbent is determined. Since the closing time of the on-off valve is calculated by calculation from the damping characteristics and the sensitivity level of the sensing element, when the amount of arc energy is small, the closing time of the on-off valve can be shortened and the time for detecting internal abnormalities can be increased. .

〔Example〕

FIGS. 1 and 2 are a cross-sectional view and an enlarged view of the main parts of an internal abnormality detection device for a gas-filled sealed electrical device showing an embodiment of the present invention. In Figures 1 and 2, (1) to (1)
4) are (1) to (14) in FIGS. 8 and 9 of the conventional example.
) is the same or equivalent part.

In FIGS. 1 and 2, (15) is a shielding part, which has a structure surrounding the sensing element (9) and has a gas intake port (15a) in a part of the shielding part SF6.

The gas intake port (15a) has an on-off valve (
16) is installed. (18) is an on-off valve controller which sends an electric signal to the on-off valve (16) through an on-off valve signal line (17) to differentially open and close the on-off valve (16). (20
) is an operation switch built into the circuit breaker control panel (14), which sends the opening/closing operation signal of the circuit breaker (λ) to the opening/closing valve controller (18) through the opening/closing signal line (19). (16) A reference time for the opening/closing operation is set.

The operation of an embodiment of the present invention constructed as shown in FIGS. 1 and 2 will be explained with reference to FIGS. 3 to 6. Figure 3~
Fig. 5 is a diagram against time showing the operating principle. In each figure, (a) shows the open/closed state of the circuit breaker (2), "open" or "closed", and (b) shows the sealed container ( SF in 1) indicates the concentration state of the decomposed gas concentration, and (c) indicates the open/close state of the on-off valve (16), "open" or "closed".

Figure 3 shows the operation of the circuit breaker (2) when the normal opening operation "Closing - Opening" is performed. First, the circuit breaker (?)
During normal use when the circuit is closed and the rated voltage is applied, the on-off valve (16) remains open and the SF.

SF containing decomposed gas, gas (8) and sensing element (9) are brought into contact to detect internal abnormalities.When the circuit breaker (2) is opened, arc discharge occurs. SF, decomposed gas is generated, and with the addition of the stirring action of the movable contactor (3), it diffuses throughout the interior of the sealed container (1) in a relatively short time, and the concentration of SF6 decomposed gas near the sensing element (9) also decreases. Because the temperature rises rapidly, the operation switch (20) on the circuit breaker control panel (14) is opened at the same time as the circuit breaker (2) is opened.
) receives the on-off operation signal from the on-off valve controller (18), which converts it into an electric signal to close the on-off valve (16) and sends it to the on-off valve (16) to close the on-off valve. (1
6) is closed to prevent SF generated by normal opening and closing operations, SF containing decomposed gas, and gas (8) from contacting the sensing element (9). After a while, the SFb decomposed gas that increased over time is also adsorbed and removed by the action of the adsorbent (not shown) installed inside the sealed container (1), and the SFb decomposed gas concentration near the sensing element (9) also decreases over time. Since it gradually decreases with the passage of time, a predetermined time (Ll) is determined based on the SF measured in advance in the actual machine and the decomposition gas concentration decrease curve, with a margin added, for example, t + = 300 hours + 50 hours +
50 Manually input into the controller (18) in advance, the on-off valve control WS (17) generates electricity to open the on-off valve (16) after a predetermined time (t,) from the time of the electric circuit opening/closing operation (reference time). A signal is sent to open the on-off valve (16) so that the SF gas (8) containing the SF4 decomposed gas comes into contact with the sensing element (9), thereby detecting an internal abnormality again.

Figure 4 shows the operation of the circuit breaker (2) when the normal closing operation "open-close" is performed. First, the circuit breaker (?)
When the on-off valve (1
6) is left open to allow SFa gas (8) containing SF6 decomposition gas to come into contact with the sensing element (9) to detect internal abnormalities. Next, when the circuit breaker (2) is operated to close, arc discharge causes S
F4 decomposition gas is generated, and the SF & decomposition gas concentration near the sensing element (9) rises rapidly, so at the same time as the circuit switch (?) is closed, the on/off valve is activated with the same signal flow as the above-mentioned "Closing - Opening". SF generated by closing (16) and normal opening/closing operation.

SF containing cracked gas. The gas (8) is prevented from contacting the sensing element (9), but after a while the SF. Since the cracked gas tla degree gradually decreases over time, the SF.
A predetermined time (t2), for example, tz=l, which is determined from the decomposition gas concentration decreasing curve with a margin added.

0 hour + 50 hours - 150 hours on/off valve controller (18)
Manually input in advance, and at the time of circuit opening/closing operation (
After a predetermined time (t2) from the reference time (reference time), the on-off valve (16) is used to open the SF. The gas (8) is brought into contact with the sensing element (9) to detect an internal abnormality again.

Figure 5 shows the normal closing operation of the circuit breaker (2) again during the period when the on-off valve (16) is closed after the normal opening operation of the circuit breaker (2), ``Closing - Open''. The on-off valve (16) is opened and closed in the same manner as in "Closing circuit", but for a predetermined period of time 1 =
1, +12 Here, 1 is the predetermined time for closing and opening, and t2 is the predetermined time for opening and closing.
It is similar to "open circuit" or "open circuit-closed circuit." Also, although not shown or explained, the on-off valve (
The predetermined time when the normal opening operation "Closing - Opening" is performed during the time period when 16) is closed is also 1 = 1, + 1.

Here, the decrease curve of the SF6 decomposed gas production amount and the SFa decomposed gas concentration when the circuit switch (2) is opened and closed normally will be explained using FIG. 6.

SF generated by arc discharge when normal opening/closing operations are performed. The amount of decomposed gas depends on the arc energy between the fixed contact (4) and the movable contact (3), and the relationship is as follows: SF6 decomposed gas production amount α (arc current) 2 ×
(arc duration). Here the arc current is a closed circuit −
This is the breaking current at the time of opening or the input current at the time of opening and closing, and is the current value that can be measured immediately before or after the opening/closing operation of the circuit breaker (2).
) stroke distance, stroke speed and applied voltage (
The time value is determined by the operating voltage), but since it is actually used at the rated voltage (a constant value), the time value is determined by the rated voltage (constant value).

The respective time values at the time of opening and closing are approximately constant values.

Therefore, the amount of SF1 decomposition gas produced is (square of arc current)
x becomes a constant value, and this becomes the initial value (peak value) of the SF and cracked gas concentration decreasing curve (see FIG. 6).

Figure 6 is a diagram showing the operating principle versus time.
Normal opening/closing operation of class SF, gas-filled sealed type circuit breaker "closed-open" breaking current 3000A, breaking time 20m
The measurement results of SF and cracked gas concentration when performing 5ec are the initial value 1.3 hydrogen fluoride equivalent parts per million (rwt p).
pm as HFJ), but after 500 hours it became 0.013wt ppm as HF.

If the sensitivity level of the sensing element (9) is 1wt ppIg
If as IF is used, the prescribed time for closing the on-off valve (16) is 25 hours based on the SF and decomposition gas concentration decrease curve (Figure 6), but considering the irreversible characteristics of the sensing element (9). and its sensitivity level is 0.1wt ppm as
In the case of HF, the time calculated from the decreasing surface vA (Fig. 6) of the SFh decomposed gas concentration is 300 hours, and the on-off valve controller (
18) will be entered manually. Therefore, when the circuit switch (2) is opened, the on-off valve (16) is immediately closed, and after a predetermined period of 350 hours, the on-off valve (16) is opened to detect an internal abnormality again.

Through the operations shown in FIGS. 3 to 6 above, the internal abnormality detection device for gas-filled sealed electrical equipment according to an embodiment of the present invention detects that when the circuit breaker (2) is normally opened and closed, Immediately after, a predetermined time period, for example, 1° hour, t2 hour, 1. +1
．． By not operating the sensing element (9) for a certain period of time, internal abnormalities are not detected, and by activating the sensing element (9) after a predetermined period of time, internal abnormalities are detected again. do. Note that the predetermined time when the normal opening/closing operation is performed n1 times for closing and opening and n2 times for opening and closing within a short time is n, t, +n, +t2 hours.

1 and 7 are a cross-sectional view and an enlarged view of the main parts of an internal abnormality detection device for a gas-filled sealed electric appliance showing an embodiment of another invention of the present invention, but only FIG. It is a drawing common to one embodiment of this invention.

In FIGS. 1 and 7, (1) to (14) are the same or equivalent to (1) to (14) in FIGS. 8 and 9 of the conventional example, and (15) to (20) are These are the same or corresponding parts as (15) to (20) in FIG. 2 of one embodiment of the present invention.

In Fig. 7, (21) is a time calculator, which is a current transformer (ct) (2) built into the circuit breaker control panel (14).
3) through the current signal line (22) as a current signal converted from the breaking current or making current of the circuit breaker (2), and received by this time calculating device (21).
) internally calculates the closing time of the on-off valve (16), and sends the time signal to the on-off valve controller (1) through the time signal line (24).
8).

Regarding the operation of another embodiment of the present invention constructed as shown in FIGS. 1 and 7, only the points that are different from the embodiment of the present invention will be described.

In one embodiment of the present invention, as explained in FIGS. 3 to 6, a predetermined time period, for example, 1. Time + "2 hours + L
l ” L 2 hours, n, t, +n, the sensing element (
However, in another embodiment of the present invention, the predetermined time period is not set to a fixed time, and the sensing element (
9) Sensitivity level, arc duration, SF by adsorbent
, the characteristic value of the decomposed gas attenuation characteristic is input manually in advance, and the amount of arc energy is calculated inside this time calculator (21) by receiving the current signal from the current transformer (ct) (23). Calculate the closed state time of the on-off valve (16) while plotting on the concentration decrease curve,
The time obtained by the arithmetic processing is converted into a time signal and sent to the on-off valve controller (17).

Through the above-described operation, the internal abnormality detection device for gas-filled sealed electrical equipment according to another embodiment of the present invention operates as a circuit breaker (
2) The time period calculated from the amount of arc energy after the normal opening/closing operation, for example, r.

(XI+Vl+Z+) +' z(Xz, Vz, Zz
), by not operating the sensing element (9), internal abnormalities are not detected.
Predetermined time LI+ ”t+ t,+ of one embodiment of the present invention
This has the advantage that the downtime can be shorter than a constant time such as t.

〔Effect of the invention〕

As explained above, in this invention, there is no risk that the sensing element will come into contact with SF or decomposed gas generated during normal opening/closing operations, so internal abnormalities can be reliably detected and the characteristics of the irreversible sensing element can be prevented from deteriorating. Since this can be prevented, the sensing element can be used for a long period of time, and there is no need for wasteful replacement work of the sensing element.

Another invention of the present invention operates the sensing element by calculating the closing time period of the on-off valve based on the generation scale of SF6 decomposed gas generated in accordance with the amount of arc energy, so the down time of internal abnormality detection in this invention In contrast, since the down time for internal abnormality detection in another aspect of the present invention is shortened, the detecting device has an advantage that the detectable time becomes longer and the detection device becomes more effective.

[Brief explanation of the drawing]

FIG. 1 is a common sectional view showing an embodiment of the present invention and an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1 showing an embodiment of the invention, and FIGS. FIG. 6 is a time diagram for explaining the operating principle of this invention. FIG. 7 is an enlarged view of the main part of FIG. 1 showing an embodiment of another invention of the present invention, and FIG. 8 is a sectional view showing a conventional example. FIG. 9 is an enlarged view of the main part of FIG. 8 showing a conventional example. In the figure, (1) is a sealed container, and (2) is an electric circuit switch. (8) is SF, gas, (9) is sensing element, (11) is resistance measuring device, (12) is level detector, (13) is indicator, (15) is shielding part, (15a) is shielding Department S
F is a gas intake port, (16) is an on-off valve, (18) is an on-off valve controller, and (21) is a time calculator. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (7)

[Claims] (1) A circuit breaker is placed in a sulfur hexafluoride (hereinafter referred to as "SF_6") gas atmosphere sealed in a sealable container (hereinafter referred to as a "sealed container"), and generated due to an internal abnormality in this circuit breaker. This S
An adsorbent that adsorbs and removes the F_6 decomposed gas and a sensing element with irreversible characteristics whose electrical resistance value decreases when it comes into contact with the SF_6 gas are provided in the sealed container, and a resistor that measures the decrease in the electrical resistance value of the sensing element. The interior of a gas-filled sealed electrical device that is equipped with a measuring device, a level detector that detects when the measured value of the resistance measuring device reaches a set level, and an indicator that displays an abnormality when the measured value of the resistance measuring device exceeds the set level. In the abnormality detection device, a shielding part is provided to shield the sensing element from the SF_6 gas atmosphere, and a part of the shielding part is provided with an SF_6 gas intake port having an on-off valve, and the opening/closing operation is performed when the electric circuit switch is opened or closed. An internal abnormality detection device for a gas-filled sealed electrical appliance, comprising an on-off valve controller that closes the on-off valve in response to a signal and opens the on-off valve after a predetermined period of time. (2) The internal abnormality detection device for a gas-filled sealed electrical appliance according to claim 1, wherein a constant time is set as the predetermined time regardless of whether an electric circuit switch is opened or closed. (3) The gas-filled sealed electric device according to claim 1, characterized in that a first fixed time during an opening operation of the circuit breaker and a second fixed time during a closing operation are set as the predetermined time. Internal anomaly detection device. (4) As the predetermined time (number of opening operations of the circuit breaker) x (
The gas-filled sealed type according to claim 1, characterized in that the time is set as the sum of (first fixed time) and (number of closing operations of the circuit breaker) x (second fixed time). Internal abnormality detection device for electrical equipment. (5) A circuit breaker is placed in the SF_6 gas atmosphere sealed in a sealed container, and the SF generated by the circuit breaker
An adsorbent that adsorbs and removes the SF_6 decomposed gas when brought into contact with the SF_6 decomposed gas and a sensing element with irreversible characteristics whose electrical resistance value decreases when it comes into contact with the SF_6 gas are provided in the sealed container, and the sensing element A resistance measuring device that measures the electrical resistance value of the resistance measuring device, a level detector that detects when the measured value of the resistance measuring device reaches a set level, and an indicator that displays an abnormality when the measured value of the resistance measuring device exceeds the set level. In the internal abnormality detection device for gas-filled sealed electrical equipment, a shielding part is provided to shield the sensing element from the SF_6 gas atmosphere, and an SF_6 gas intake port with an on-off valve is provided in a part of the shielding part. S due to the above adsorbent obtained and input in
F_6 The closing time of the on-off valve is calculated from the input sensitivity level set for the sensing element and the amount of arc energy obtained by receiving a current signal proportional to the current of the circuit breaker using the decrease curve of the F_6 decomposition gas concentration. , is provided with a time calculator for outputting, and receives an opening/closing operation signal when the circuit switch is opened or closed, closes the opening/closing valve, performs arithmetic processing in the time calculator, and opens the opening/closing valve after the output time. An internal abnormality detection device for a gas-filled sealed electrical device, characterized by being equipped with an on-off valve controller. (6) When the opening/closing operation of a circuit breaker is performed multiple times within a short period of time, the time calculation device calculates the output time for each opening or closing operation, and then 6. The internal abnormality detection device for gas-filled sealed electrical equipment according to claim 5, characterized in that the calculation is performed as a simple sum of times. (7) When the circuit breaker is opened and closed multiple times within a short period of time, the time calculation device calculates and outputs the time SF_
6. An internal abnormality detection device for a gas-filled sealed electrical appliance according to claim 5, wherein calculation is performed on each decomposition gas concentration decreasing curve as time passes and calculation is made as a composite sum.