JPS61107620A - Vacuum deficiency detector for vacuum switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vacuum failure detection device for a vacuum container in a vacuum switch used in a closed switchboard or the like.

[Technical background of the invention and its problems]

Normally, the inside of the vacuum container in a vacuum switch is 10'To
It is maintained at a high degree of vacuum of RR or higher and maintains its performance as a switch, but if it is opened and closed frequently or if it has been used for many years, the vacuum level may decrease and cause vacuum failure. It's coming.

Generally speaking, the relationship between the degree of vacuum and the dielectric strength of a vacuum container is as shown in the characteristic diagram shown in Figure 5.When the degree of vacuum is about 1047 orr or higher, the withstand voltage is higher than the rated voltage, but when the degree of vacuum decreases, the dielectric strength is higher than the rated voltage. The withstand voltage also decreases in accordance with the decrease. When the degree of vacuum is between 10 degrees and 1 Torr, the withstand voltage value is the lowest, and then increases as the pressure approaches atmospheric pressure, exhibiting the so-called Paschen's law characteristic.

As described above, a decrease in the degree of vacuum in a vacuum container generally hardly occurs suddenly and progresses gradually. For this reason, the vacuum container of the vacuum switch in use deteriorates and the degree of vacuum decreases, and when the degree of vacuum eventually becomes 10'2 Torr or less, the withstand voltage value with the electrodes open will change to the normal earth withstand voltage E1 (=
EX1/f3) or less, discharge occurs between the electrodes and leakage current flows.

By the way, in conventional vacuum switches used with surge protectors in closed switchboards, etc., to detect a vacuum failure in a vacuum container, the leakage current flowing through the vacuum container is detected, and the quality of the leakage current is determined based on the size of this current. things are being adopted. However, as recent vacuum containers have become smaller and lighter, creepage insulation distances have become smaller, and they are not necessarily used in good environmental conditions, especially in bad environments such as outdoor closed switchboards. In the case of a vacuum switch, dirt or moisture may cause a vacuum failure in the vacuum container, causing a leakage current greater than the leakage current that flows when the vacuum switch is closed.

Therefore, if the vacuum container leakage current detection device used in the past determines the quality of the vacuum defect based solely on the magnitude of the leakage current, the surface of the vacuum container may become contaminated or wet due to adverse environmental conditions. Even if a vacuum failure does not occur, the leakage current will increase, and it will be detected as if a vacuum failure had occurred.

Here, the relationship between the leakage current on the surface of the vacuum container, the degree of contamination, and the relative humidity will be described with reference to FIG. In Figure 6,
(A) has a pollution degree of 0, and (B) has a pollution degree of 0.01ttt.
ylcd, (c) is the characteristic when the degree of contamination is 0.03 Q/ci, and as is clear from this characteristic, it can be seen that the leakage current increases as the degree of contamination and relative humidity increase. Therefore, when the leakage current flowing into the vacuum container exceeds the leakage current set value 11 shown in FIG. 6, the detection device will naturally operate. Furthermore, the leakage current has a characteristic that it decreases with the elapsed time of voltage application (the time after the vacuum switch is opened in normal use). FIG. 7 shows an example. That is, in FIG. 7, the degree of contamination is 0.03 rng.
The relationship between the leakage current and the elapsed voltage application time is shown for the case of /csl, where (d) is the characteristic when the relative humidity is 80%, and (e) is the characteristic when the relative humidity is 100%.

If the vacuum switch is installed in an environment where it is contaminated or wet, the leakage current may exceed the set value of 11 even though there is no vacuum defect in the vacuum container. This results in the detection as if there is a vacuum defect in the vacuum container and displays or issues an alarm to that effect, resulting in a problem that the vacuum switch lacks reliability as a vacuum defect detection device.

[Purpose of the invention]

The present invention was made in view of the above-mentioned circumstances, and its purpose is to prevent an increase in leakage current from occurring even when the vacuum container of a vacuum switch is installed under environmental conditions where it is susceptible to contamination and moisture. By distinguishing whether the problem is caused by a vacuum failure or by a vacuum failure, and displaying or warning to that effect, the system can reliably determine whether the environmental conditions are good or bad at the same time as the original purpose of determining a vacuum failure. The purpose of the present invention is to provide a high vacuum failure detection device for a vacuum switch.

(Summary of the Invention) In order to achieve the above object, the present invention adjusts the output of a leakage current detection voltage divider connected in series to each phase between the load side and the ground of a vacuum switch according to the magnitude of the leakage current. A leakage current detection device that generates a number of pulses and outputs a leakage current detection signal when the number of pulses exceeds a set value is applied to the output of the leakage current detection device and the surrounding environment in which the vacuum switch is installed. The output of the humidity detection device which detects the humidity of a first discrimination circuit that indicates that a leakage current is flowing and also discriminates that a vacuum failure has occurred in the vacuum container of the vacuum switch, and displays or alarms to that effect; and the leakage current detection signal; For both signal inputs of the humidity detection signal, a second discrimination port t blocks the vacuum defect discrimination function, discriminates that the leakage current is caused by contamination or moisture, and displays or alarms to that effect. It is characterized by the fact that it is equipped with

In addition, when a leakage current detection signal is input from the leakage current detection device corresponding to each phase, the discrimination device determines that a vacuum failure has occurred in the vacuum vessel of the vacuum switch of that phase and displays a display to that effect. Or, when it is detected that the leakage current detection signal is output from all of the first discrimination circuit for alarming and the leakage current detection device of each phase, it is determined that the leakage current is due to contamination and moisture, and a display to that effect is displayed. By being configured with a second discrimination circuit that issues an alarm, it is possible to determine whether an increase in leakage current is due to contamination, humidity, or a vacuum failure in the vacuum container without using a humidity detection device. It is something to do.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of a vacuum defect detection device for a vacuum switch according to the present invention, and in this embodiment, the internal circuit of the closed panel is shown as a single-phase wiring diagram.

In Fig. 1, 1 is a closed switchboard, and this closed switchboard 1
The power supply side bus bar and the load side cable 3 are wired inside the
Furthermore, a vacuum switch 4, a surge protection device 15, a leakage current detection voltage divider 6, a leakage current detection device 7, a humidity detection device 8, and a discrimination device 9 are housed, respectively.

The vacuum switch 4 has its power supply side end connected to the power supply bus 2, and a surge protection device 5 and a voltage divider 6 for detecting leakage current are connected in series to each phase between the load side end and the ground. . A leakage current detection device 7 is connected to the output terminal of the leakage current detection voltage divider 6, which generates a number of pulses according to the magnitude of the leakage current and outputs a leakage current detection signal when the number of pulses exceeds a set value. has been done. The humidity detection device 8 detects the humidity around the vacuum switch 4 and outputs a humidity detection signal when the humidity exceeds a predetermined value. A leakage current detection signal outputted from the leakage current detection device 7 and a humidity detection signal outputted from the humidity detection device 8 are respectively applied to the discrimination device 9, and a leakage current flows when only the leakage current detection signal is input. A first discrimination circuit that determines that a vacuum failure has occurred in the vacuum container of the vacuum opening/closing H4 and displays that fact, and a signal input for both a leakage current detection signal and a humidity detection signal. In contrast, the first discrimination circuit disables the vacuum failure discrimination, and the second discrimination circuit discriminates that the leakage current is due to contamination and moisture, and displays the fact.

The second factor shows a specific example of the circuit configuration of the discriminating device 9. In FIG. 2, 10 is a normally open leakage current detection contact that closes when a leakage current detection signal is input from the leakage current detection device 7, and 11 is a normally open humidity detection contact that closes when a humidity detection signal is input from the humidity detection device 8. 12 is a normally closed humidity detection contact that similarly opens when a humidity detection signal is input from the humidity detection device 8, 13 is a vacuum failure indicator lamp, 14 is a vacuum failure detection relay, 15 is a high humidity indicator lamp, and 16 is a high humidity A detection relay, 17 is a leakage current display lamp, and 18 is a leakage current detection relay.

Therefore, the leakage current detection normally open contact 10. Humidity detection normally closed contact 12 and vacuum defect detection relay 14 are connected in series to control m'
Connect to source bus P and N. Then, a vacuum failure indicator lamp 13 is connected in parallel to the vacuum failure detection relay 14, and the humidity detection normally closed contact 12 and the vacuum failure detection relay 14 are connected in parallel.
A leakage current detection relay 18 and a leakage current display lamp 17 are respectively connected in parallel to the series circuit. This connection circuit constitutes a first discrimination circuit. Also, the humidity detection normally open contact 11 and the high humidity detection relay 16 are connected in series.
A high humidity display lamp 15 is connected between the N source busbars and in parallel with the high humidity detection relay 16. This connection circuit constitutes a second discrimination circuit.

Next, the operation of the vacuum defect detection device for vacuum #1 closure configured as described above will be described. First, a case will be described in which a leakage current due to a decrease in the degree of vacuum in the vacuum container is detected when the vacuum switch 4 is opened. Now, assuming that the humidity detection signal is not output from the humidity detection device 8 provided in the closed switchboard 1, the humidity detection normally open contact 11 of the discrimination device 9 shown in FIG. Normally open contact 12 is closed. Under such conditions, if a vacuum decreases in the vacuum container of the vacuum switch 4 and its insulation properties drop below a certain degree of vacuum as shown in Figure 5, the withstand voltage of the vacuum container will become below the normal ground voltage. , an internal discharge occurs. Therefore, this internal discharge causes leakage current to flow from the power supply bus 2 to the vacuum open rr.
I device 4. Surge protection device 5 and leakage current detection voltage divider 6
flows through to the ground point. Then, this leakage current is taken out by a leakage current detection voltage divider 6 and applied to a leakage current detection device 7. The leakage current detection device 7 generates a number of pulses depending on the magnitude of the leakage current, and if the number of pulses is equal to or greater than a set value, a leakage current detection signal is input to the discrimination device 9. In this discrimination device 9, the leakage current detection normally open contact 1o is closed by inputting the leakage current detection signal, so the leakage current detection relay 18 is operated and the leakage current display lamp 1
7 indicates that. Also, at this time, since the humidity detection normally closed contact 12 is open, the vacuum failure detection relay 14 is activated.
: At the same time, the vacuum indicator lamp 13 indicates that. Therefore, the operation of the leakage current detection relay 18 and the display of the leakage current indicator lamp 17 indicate that a leakage current has flown, and the operation of the vacuum failure detection relay 14 and the display of the vacuum failure indicator lamp indicate that the leakage current at that time is detected in the vacuum vessel. It can be seen that this is due to a vacuum failure.

Next, the environmental conditions inside the closed arrangement ia deteriorate and the vacuum switch 4
The operation when a leakage current flows to the ground point through the vacuum vessel, surge protector 5, and leakage current detection voltage divider 6 will be described. In this case, since the humidity detection signal is input from the humidity detection device 18 to the discrimination device 9, the humidity detection normally open contact 11 is closed in the discrimination device 9 shown in FIG.
Humidity detection normally closed contact 12 is open. In such a state, when the leakage current is extracted by the leakage current detection voltage divider 6 and inputted to the discrimination device 9 as described above, the leakage current detection relay 18 is activated by closing the leakage current detection normally open contact 10. As soon as the leakage current indicator lamp 17 operates, the leakage current display lamp 17 indicates this. However, at this time, the humidity detection normally closed contact 12 is open, so the vacuum failure detection relay 14 does not operate, and the vacuum failure indicator lamp 13-82 does not light up. In addition, the high humidity detection relay 16 is activated by closing the humidity detection normally open contact 11.

The high humidity indicator lamp 15 indicates this. Therefore,
In the case of such an operation and display, it can be determined that the leakage current at that time is caused by contamination and moisture due to deterioration of the environmental conditions inside the closed switchboard.

With the configuration as in the above embodiment, it is possible to reliably determine whether the increase in wetting current is due to deterioration of the environmental conditions in which the vacuum switch is installed or due to a vacuum failure in the vacuum container. can. In addition, by making it possible to determine leakage current, in the event of deterioration of environmental conditions, the operation at that time can be used as a maintenance standard for equipment depending on the environmental conditions, thereby preventing the development of serious accidents. I can do it.

Next, another embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In Fig. 3, 21 is a three-phase power supply bus consisting of R, S, and T phases. .

24, connect the power side terminals of the T-phase vacuum switch 25, and connect the load-side terminals to the load-side cable 22, and also connect the R-phase S-J protection device 26, the S-phase S-J protection device 27, The T-phase protection device 28 and the leakage current detection voltage divider 29 are connected in series to a ground point.

In addition, the output of the leakage TL inflow/output voltage divider 29 is connected to the R-phase leakage current detection device [30, S-phase leakage current detection device f! 31, T-phase leakage and R flow detection device 132 respectively. Leakage current detection devices 30, 31, 32 for each of these phases
When a leakage current is input, it generates a number of pulses according to the magnitude of the leakage current, and when this number of pulses exceeds a set value, it outputs a leakage current detection signal. These leakage current detection devices 30. ．． The outputs of 31° and 32 are applied to the discriminator 33, respectively. This discrimination device 33 is constructed in a circuit as shown in FIG. That is, as shown in FIG. 4, the control power bus P is connected by connecting the contact 34, which closes when a leakage current detection signal is inputted from the R-phase leakage current detection device 30, and the R-phase vacuum defect display relay 37 in series.
, N. In addition, the S phase leakage current detection device 113
Contact 35 that closes when a leakage current detection signal is input from 1
and the S-phase vacuum defect display relay 38 are connected in series between the control power supply buses P and N. Similarly, a contact 36 that closes when a leakage current detection signal is input from the T-phase leakage current detection device 32 and a T-phase vacuum defect display relay 39 are connected in series between the control power supply buses P and N. Such a connection circuit constitutes a first discrimination circuit. In addition, a control power bus P, in which a series circuit of contacts 34, 35, 36 that close when a leakage current detection signal is input from each phase leakage current detection device 30, 31, 32, and an environmental condition failure display relay 40 are connected in series. A second discriminating circuit is configured by connecting between the two discriminating circuits.

Next, the operation of the vacuum defect detection device for a vacuum switch configured as described above will be described.

In general, the rate of decrease in the degree of vacuum in a vacuum container is extremely slow, and the probability of vacuum failure occurring is extremely small, so it can be said that there is no phenomenon in which vacuum failure occurs simultaneously in three-phase vacuum vessels. In addition, if the leakage current increases due to dirt or moisture on the vacuum switch, it is unlikely that only one or two of the three phases of the vacuum vessel will be in this condition;
Although there are some differences in wetness, the increase in leakage current tends to be the same not only in one-phase or two-phase vacuum vessels, but also in three-phase vacuum vessels, and under adverse environmental conditions, leakage occurs in all three-phase vacuum vessels. The current will increase.

Therefore, if a leakage current flows due to a vacuum failure in the vacuum vessel of one or two of the R, S, and T phases, one of the vacuum failure display relays 37 to 39 corresponding to that phase will operate. However, the poor environmental condition display relay 40 is inoperative, and from this it can be determined that the increase in leakage current is due to a vacuum defect in the vacuum container. Also, due to bad environmental conditions,
If the vacuum vessels of each of the three phases are contaminated or wet and a leakage current flows, all of the leakage current display relays 37 to 39 of each phase are activated, but at this time, the environmental condition failure display relay 4 is activated.
0 also operates, so it can be determined that the increase in leakage current is caused by contamination or moisture due to bad environmental conditions.

In each of the above-mentioned embodiments, a case has been described for detecting a vacuum defect in a vacuum container of a vacuum switch, but the present invention can also be applied to detect a leakage current due to element deterioration of a surge protection device. . In this case, the leakage current detection device (corresponding to 9 degrees in Figure 1 and 30 to 32 in Figure 3) generates the number of pulses depending on the magnitude of the leakage current, so
By appropriately selecting the set value, it is possible to detect element deterioration of the surge protection device.

〔Effect of the invention〕

As described above, according to the present invention, even if the vacuum container of the vacuum switch is installed under environmental conditions where it is susceptible to contamination or moisture, the increase in leakage current may be due to contamination or moisture, or due to a vacuum defect. By determining whether a vacuum is present or not and displaying or giving an alarm to that effect, a highly reliable vacuum switch can be used to reliably determine whether the environmental conditions are good or bad at the same time as the original purpose of determining whether the vacuum is defective. A vacuum defect detection device can be provided.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing one embodiment of the vacuum defect detection device for a vacuum switch according to the present invention, the second cause is a specific circuit diagram of a discrimination device in the same embodiment, and FIG. FIG. 4 is a specific circuit diagram of the discriminating device in the same embodiment, FIG. 5 is a characteristic diagram showing the relationship between the degree of vacuum of the vacuum container and the dielectric breakdown voltage, and FIG. Characteristic diagram showing the relationship between relative humidity and degree of contamination of edge surface leakage current of a vacuum container,
FIG. 7 is a diagram showing the attenuation characteristic of the edge surface leakage current of the vacuum container after voltage application. 1... Closed switchboard, 4... Vacuum switch, 5... Surge protection device, 6... Leakage current detection voltage divider, 7...
・Leakage current detection device, 8... Humidity detection device, 9...
Discrimination device, 14... Vacuum defect detection relay, 16...
^Humidity detection relay, 18...Leakage current detection relay, 1
3.15°17...Indication lamp. Applicant's representative Patent attorney Takehiko Suzue No. 1 Cause, Figure 2, Figure 3, Prisoner, Figure 4, Figure 5, Intention and Obedience (TOYY) -

Claims (2)

[Claims] (1) A leakage current detection voltage divider connected in series to each phase between the load side and ground of the vacuum switch, and the output of this leakage current detection voltage divider is added to the number of pulses depending on the magnitude of the leakage current. and a leakage current detection device that outputs a leakage current detection signal when the number of pulses exceeds a set value, and a leakage current detection device that is installed at an appropriate position in the environment where the vacuum switch is installed, A humidity detection device that detects humidity and outputs a humidity detection signal when the humidity exceeds a predetermined value, and a leakage current detection signal output from the leakage current detection device and a humidity detection signal output from the humidity detection device. In response to input of only the leakage current detection signal, it is displayed that a leakage current is flowing, and it is also determined that a vacuum failure has occurred in the vacuum container of the vacuum switch, and a notification is made to that effect. A first discrimination circuit that displays or alarms, and a signal input of both the leakage current detection signal and the humidity detection signal, prevents the vacuum defect discrimination function of the first discrimination circuit and prevents the leakage current from contaminating or damping. 1. A vacuum defect detection device for a vacuum switch, comprising: a discrimination device equipped with a second discrimination circuit that discriminates whether the defect is caused by the defect and displays or gives an alarm to that effect. (2) A leakage current detection voltage divider connected in series to each phase between the load side and ground of the vacuum switch, and the output of this leakage current detection voltage divider is added to the number of pulses depending on the magnitude of the leakage current. A leakage current detection device for each phase outputs a leakage current detection signal when the number of pulses exceeds a set value, and a leakage current detection signal is input from the leakage current detection device provided corresponding to each phase. a first discrimination circuit that determines that a vacuum failure has occurred in the vacuum vessel of the vacuum switch of that phase and displays or alarms to that effect, and all of the leakage current detection devices corresponding to each phase. A discriminating device comprising a second discriminating circuit that detects that a leakage current detection signal is output, determines that the leakage current is due to contamination or moisture, and displays or alarms to that effect. Vacuum defect detection device.