JPH033327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum level monitoring device for a vacuum shield breaker.

Generally, the vacuum degree of a vacuum disconnector is 10 ^-4 Torr.
It is normal or has the ability to break at pressures below,
This vacuum level may deteriorate due to gas released from inside the breaker or disconnector, or slow leakage from joints such as welding and brazing, resulting in a decrease in breaker ability. For this reason, when using a vacuum chamber or disconnector, it is essential to monitor the degree of vacuum in order to guarantee performance.

Therefore, in the past, a discharge electrode was installed inside the vacuum chamber or disconnector, and a high voltage was applied from a separate power source, and the degree of vacuum was checked by taking advantage of the fact that the discharge state at this time changed depending on the degree of vacuum. However, with this method, the structure of the vacuum shield and disconnector was complicated, and a separate high-voltage power source had to be provided, making it expensive. Also, when checking the degree of vacuum, if the vacuum shield or breaker is disconnected from the circuit, open the movable electrode of the vacuum shield or breaker from the fixed electrode by a distance that is likely to cause discharge due to vacuum deterioration, and connect the A voltage was applied, and the quality of the vacuum was judged based on the discharge state at this time. This method required turning off the power, which was very troublesome.

In addition, in recent years, compact substation equipment has been developed, and vacuum shields and disconnectors are also used in this equipment. In order to check the degree of vacuum in the vacuum shield or disconnector in this equipment, it is necessary to extract the oil or gas that is the insulating medium inside the equipment, disconnect the vacuum shield or disconnector from the circuit as described above, and then check. It was on.
For this reason, this checking means has the drawback of being very time consuming. Furthermore, with the above method, there was a possibility that accidents could occur due to human assembly errors.

The present invention eliminates the above-mentioned drawbacks, and eliminates the need for a separate electrical discharge pole or high-voltage power source, and allows the vacuum circuit breaker, which is housed in a case kept at ground potential, to remain connected to the circuit. It is an object of the present invention to provide a vacuum degree monitoring device for a vacuum chamber or disconnector which can check the degree of vacuum, and which can check the degree of vacuum simply and inexpensively.

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

First, let's talk about the vacuum shield disconnector. In Figure 1, 1 is a vacuum shield disconnector, and the vacuum shield disconnector 1 is a vacuum vessel with metal end plates 3 and 4 attached to both ends of an insulating cylinder 2. A fixed lead 5 is inserted into the end plate 3, and a movable lead 7 is movably inserted into the end plate 4 via a bellows 6. Attach the fixed electrode 8 and the movable electrode 9. Further, a shield 10 is installed in the middle of the insulating tube 2 to prevent metal vapor generated between the chopping electrodes 8 and 9 from adhering to the inner surface of the insulating tube 2. 11 and 12 are auxiliary shields, 13 and 14 are external connection conductors, and 15 is a current collector. Reference numeral 16 denotes an electromagnetic wave signal transmitting member, such as a coaxial cable, which is to be brought into contact with a voltage detection terminal electrically connected to a high voltage conductor that transmits the electromagnetic wave signal generated from the vacuum shield disconnector 1, and this coaxial cable 16 is connected to a detector. 17. The detector 17 includes a voltage divider 18, an amplifier 19, a determination section 20, a power supply section 21, a display section 22, a signal magnitude determination section 40, and a switching section 41.
It consists of

FIG. 2A is a block diagram showing the details of the detector 17. The coaxial cable 16 is brought into contact with a voltage detecting section of a compact substation equipment to be described later, and the signal detected by this cable 16 is sent to the signal magnitude determining section 40. Depending on the determination result, the switching unit 41 is activated, and when the detected signal is large (S ₀ shown in FIG. 2B), the voltage is passed through the voltage divider 18, and when the signal is small (S ₁ shown in FIG. 2B)
The signal is input to the buffer amplifier 23 where it is amplified as it is. 24 is the output signal of the amplifier 23 (Fig. 2B
This is a bandpass filter that passes only the frequency components from 2KHz to 20KHz from S ₁ ') shown in .

The output signal of this bandpass filter 24 (second
S ₂ ) shown in Figure B is amplified by an amplifier 25, and this amplified output signal (S ₃ shown in Figure 2 B) is input to a first comparator (hysteresis comparator) 26 and compared with a preset reference voltage. be done. At this time, when the amplified output signal _S3 exceeds the reference voltage, a signal is output from the comparator 26, but the output signal _S4 is a signal due to the hysteresis characteristic of the comparator 26, as shown in FIG. 2B. The falling time of the signal is slightly delayed. Next, the output signal S ₄ of the first comparator 26 is integrated by an integrator 27, and this integrated output signal (S ₅ shown in FIG. 2B) is input to a second comparator (hysteresis comparator) 28. It is compared with a preset reference voltage. Then, the second comparator 28 outputs a signal _S6 shown in FIG. 2B. This signal becomes an alarm and display signal.

In the above configuration, the vacuum sheath breaker 1 moves the movable lead 7 by an operating device (not shown) and connects and separates the electrodes 8 and 9 for input and disconnection. An equivalent circuit diagram is shown in FIG. In the figure, 29a to 29b are the power supply and load of the circuit in which the vacuum shield breaker 1 is installed, respectively;
30 and 31 are the portion of the fixed lead 5 inside the vacuum container and the resistance and capacitance between the fixed electrode 8 and the shield 10, respectively; 32 and 33 are the portion of the movable lead 7 inside the vacuum container and the movable electrode 9 and the shield 10, respectively.
34a and 34b are the resistances of the insulating cylinder 2, respectively, 35 is the capacitance between the shield 10 and the vacuum shield at ground potential, the disconnector and the wall of the storage tank, 3
6 and 37 are the resistance and capacitance between the electrodes 8 and 9, respectively, in the off state. When the degree of vacuum inside the vacuum shield breaker 1 deteriorates, that is, when the internal pressure increases, the capacitances 31, 33, and 37 hardly change because the dielectric constant in vacuum and the dielectric constant in the atmosphere are almost equal. However, the resistances 30, 32, and 36 are significantly reduced due to Patsien's law. For this reason,
Glow discharge occurs between the shield 10, which is insulated from both the fixed side and the movable side by the insulating cylinder 2 and has a floating potential, and each electrode 8, 9, regardless of whether it is in the closed state or the shrunk state. ，
Between 9 and 9, glow discharge occurs only in the cut-off state. This discharge changes depending on the coaxial cable (capacitance) connection on the load side, the inductive load line, or the capacitance of the vacuum shield or disconnector lead.

FIG. 4A shows the voltage between the electrodes when the degree of vacuum in the vacuum shield breaker 1 is normal, and FIG. 4B shows the signal received by the coaxial cable 16. That is, when the degree of vacuum is normal, the voltage waveform between the electrodes 8 and 9 is a sine wave as shown in FIG. A signal containing harmonics of 2KHz or less, which are likely to be generated from sources such as the following, is input. FIGS. 5A and 5B show the interelectrode voltage and the received signal of the coaxial cable 16 when the vacuum degree of the vacuum shield breaker 1 deteriorates, and the interelectrode voltage between the electrodes 8 and 9 changes as the discharge starts. As shown in FIG. 5A, the voltage does not rise above a certain level and ripples. At the start of this ripple, an electromagnetic wave signal containing a high frequency of 2 to 20 KHz is generated as shown in Figure 5B.
By detecting and determining this signal, deterioration in the degree of vacuum of the vacuum shield breaker 1 can be detected. In this case, even if corona discharge occurs in other parts than the gap between the poles and the vacuum shield or the disconnector, the signal waveform is different, so there is no effect on the detection characteristics.

FIG. 6 is a schematic circuit configuration diagram showing details of the signal magnitude determination section 40 and switching section 41 housed in the detection section 17. In FIG. 6, 40a is a buffer amplifier with high input impedance;
The coaxial cable 16 is connected to the input end of a. The output of the amplifier 40a is input to the comparison circuit section 40b. The comparison circuit section 40b is connected to the coaxial cable 16
The magnitude of the detected signal is determined, and a comparison output is sent out only when the detected signal is greater than the set value. The comparison output is input to the base of transistor 41a, and transistor 41a is turned on. As a result, the relay 41b provided in the collector circuit of the transistor 41a operates, and the relay contact portion 4
The contact 1c is switched. Therefore, when the signal level is large, the amplifier 2
A detection signal is input to 3.

Next, a compact substation equipment equipped with a voltage detection terminal to which the coaxial cable 16 comes into contact will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic configuration diagram showing the above-mentioned substation equipment in a single wire connection (usually used in three-phase). In FIG. A second tank 54 is connected to the first tank 51 via a connection duct 101 and houses connection conductors 53c and 53d to the power supply side cable 53a and load side cable 53b. This is a third tank that is connected to the third tank and houses a disconnector 55. Each tank 51, 52, 54 and duct 101 are made of metal and are kept at ground potential. In addition, each tank 51, 5
An insulating medium is stored in the tanks 2 and 54 and the duct 101, and each tank and duct are airtightly partitioned by an insulating spacer 102, respectively.

The second tank 52 is provided with a voltage detection terminal 57 using a capacitor combination 56 whose details are shown in FIG. In FIG. 8, this terminal 57 connects one end of the capacitor combination 56 to the connecting conductor 53c.
and connect the other end to the outer wall 52 of the second tank 52.
It is provided so as to be led out to the outside via an insulator 58 fixed to a.

As described above, according to the present invention, internal discharge occurs when the vacuum level of the vacuum shield breaker decreases, and the electromagnetic wave signal caused by the discharge is detected by the coaxial cable that contacts the voltage detection terminal, and the detected signal level is When it is large, it is supplied via a voltage divider, and when it is small, it is supplied directly to a detector with a bandpass filter that passes only the frequency components of 2KHz to 20KHz. Not only can deterioration be detected reliably, but it can also be reliably detected without being affected by external electrical noise. In addition, when detecting vacuum deterioration, there is no need to remove the vacuum shield or disconnector from the circuit, there is no need to change the structure of the vacuum shield or disconnector, or to install a separate high-voltage power supply. Deterioration can be detected accurately.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view of a vacuum breaker equipped with a vacuum monitoring device, Fig. 2A is a block diagram showing details of the detection section used in the vacuum monitoring device, and Fig. 2B
2A is an output waveform diagram of each part in FIG. 2A, FIG. 3 is an equivalent circuit diagram of the vacuum shield breaker shown in FIG.
1 is an operating waveform diagram of the vacuum shield breaker shown in FIG. 1, FIG. 6 is a schematic circuit diagram showing details of the signal magnitude determination section and switching section, and FIG. 7 is an embodiment of the present invention. A schematic diagram of the compact substation equipment, Figure 8 is A in Figure 7.
FIG. 1... Vacuum shield disconnector, 16... Coaxial cable,
17...Detection unit, 24...Band pass filter,
18... Voltage divider, 40... Signal magnitude determination section, 41
...Switching section, 57...Voltage detection terminal.

Claims (1)

[Scope of Claims] 1. A first tank that is maintained at ground potential and houses a vacuum shield and disconnector; and a second tank that is connected to the first tank via a connection duct that is maintained at ground potential. a tank; a connecting conductor housed in the first tank, the connecting duct, and the second tank and connected to the fixed lead and the movable lead of the vacuum shield disconnector; and one end connected to the second tank; a voltage detection terminal electrically coupled to a conductor, the other end of which is led out of the tank via an insulator fixed to the second tank; and an electromagnetic wave signal generated by internal glow discharge of the vacuum shield and disconnector. is detected by a coaxial cable that is in contact with the voltage detection terminal, and the detected signal is judged by a signal size judgment section. Based on the judgment result, if the signal is large, it is sent through a voltage divider, or if the signal is small, it is sent directly. , a detector that supplies the signal to a bandpass filter that passes only frequency components from 2KHz to 20KHz, and determines whether the degree of vacuum is good or bad based on the result of comparing the level of the signal that has passed through the filter with a preset reference signal. A vacuum level monitoring device for a vacuum shield and disconnector.