JPS645648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum degree 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.

Conventionally, a discharge electrode is provided inside the vacuum chamber or disconnector, and a high voltage is applied from a separate power supply. At this time, the discharge state according to Patsien's method changes depending on the degree of vacuum, and this is used to control the degree of vacuum. However, this method complicated the structure of the vacuum shield and disconnector, and required a separate high-voltage power source, making it expensive. Furthermore, when checking the degree of vacuum, if the vacuum shield or breaker is disconnected from the circuit, the movable electrode of the vacuum shield or breaker is replaced by the fixed electrode depending on Patsien's law due to the deterioration of the vacuum degree. The electrodes were opened to a distance that facilitated discharge, and a high voltage was applied from a separate power source, and the quality of the vacuum was determined based on the discharge state at this time. This method required turning off the power, which was very troublesome.

The present invention eliminates the above-mentioned drawbacks, does not require a discharge electrode or a separate high-voltage power source, and can check the vacuum level of a vacuum shield or disconnector while it is connected to the circuit. It is an object of the present invention to provide a vacuum level monitoring device for a vacuum shield or disconnector that can be checked easily and inexpensively.

The present invention will be explained below with reference to the drawings. In Fig. 1, 1 is a vacuum shield disconnector.The vacuum shield disconnector 1 has metal end plates 3 and 4 attached to both ends of an insulating cylinder 2 to form a vacuum container, and is fixed to the end plate 3. While the lead 5 is inserted, a movable lead 7 is movably inserted into the end plate 4 via a bellows 6, and a fixed electrode 8 and a movable electrode 9 are attached to the tips of the fixed lead 5 and the movable lead 7, respectively. Further, a shield 10 is installed in the middle of the insulating cylinder 2 to prevent metal vapor generated between the chopping electrodes 8 and 9 from adhering to the inner surface of the insulating cylinder 2. 11 and 12 are auxiliary shields, 13 and 14 are external connection conductors, and 15 is a current collector. 16 is an electromagnetic wave signal receiving member, such as an antenna, to be disposed near the vacuum shield breaker 1;
This antenna 16 is connected to a detector 18 by a connecting line 17.
It is connected to the. The detector 18 includes an amplifier 19, a determination section 20, a power supply section 21, and a display section 22.

FIG. 2A is a block diagram showing details of the detector 18, in which 23 is a buffer amplifier that amplifies the detection signal detected by the antenna 16, and 24 is a buffer amplifier 2.
2 to 20k from the output signal of 3 (S ₁ shown in Figure 2B)
This is a bandpass filter that passes only Hz frequency components. The output signal (S ₂ shown in FIG. 2B) of this bandpass filter 24 is amplified by the amplifier 25, and this amplified output signal (S ₃ shown in FIG. 2B)
is input to the first comparator 26 and compared with a predetermined reference voltage. The output signal of the first comparator 26 (S ₄ shown in FIG. 2B) is integrated by an integrator 27, and this integrated output signal (S ₅ shown in FIG. 2B) is input to the second comparator 28. is compared with a predetermined reference voltage of the second comparator 28, and the output is S ₆ as shown in FIG. 2B.
The signal is sent out. 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), connects and separates the electrodes 8 and 9, and disconnects the sheath, but the vacuum sheath breaker 1 is in a sheared state. The equivalent circuit diagram for
As shown in the figure. In the figure, 28 and 29 are the power supply and load of the circuit in which the vacuum shield breaker 1 is installed, and 3
0 and 31 are the resistance and capacitance between the portion of the fixed lead 5 inside the vacuum container and 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, 35 is the capacitance between the shield 10 and the ground, and 36 and 37 are the resistances and capacitances between the electrodes 8 and 9 in the disconnected state, respectively. It is the capacitance. When the degree of vacuum inside the vacuum chamber breaker 1 deteriorates, that is, when the internal pressure increases, the capacitances 31, 33,
37 hardly changes, but the resistances 30, 32,
36 is significantly reduced by a precursor phenomenon influenced by Patsien's law. Therefore, discharge occurs between the shield 10, which is insulated from both the fixed side and the movable side by the insulating tube 2 and has a floating potential, and each electrode 8, 9, regardless of whether it is in the closed state or the shrunk state. Discharge occurs between the electrodes 8 and 9 only in the disconnected state. This discharge changes depending on the cable (capacitance) connection on the load side, the inductive load line, or the capacitance of the vacuum shield or disconnector lead.

Figure 4A shows the voltage between the electrodes when the degree of vacuum in the vacuum shield breaker 1 is normal, and Figure 4B shows the voltage between the antennas 16 and 16.
The received signal is shown below. 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 thought to be generated from Figure 5 A and B are vacuum shield disconnector 1
The voltage between electrodes 8 and 9 and the received signal of antenna 16 are shown when the degree of vacuum deteriorates, and when the discharge starts, the voltage between electrodes 8 and 9 rises above a certain voltage as shown in Figure 5A. Ripple without. At the start of this ripple, an electromagnetic wave signal containing a high frequency of 2 to 20 kHz is generated as shown in FIG. In this case, even if corona discharge occurs in other parts than the vacuum chamber or the disconnector, the signal waveform will be different, so there will be no effect on the detection characteristics.

When the degree of vacuum in the vacuum shield breaker 1 deteriorates, the antenna 16 receives an electromagnetic wave signal. Vacuum level 5
The electromagnetic waves measured by changing between ×10 ^-3 and 300Torr are 10 to 14K when the ground capacitance on the load side is 0.0042μF.
Hz, includes frequencies of 2 to 8kHz when 0.05μF, 2 to 20kHz when 0.2μF or 0.2μF or more, 0.0042μF
The waveform of the electromagnetic waves at this time was pulse-like. When the capacitance on the load side is as small as 0.0042 μF or less, the electromagnetic wave detection sensitivity becomes unstable, so a capacitance of about 0.2 μF should be connected to the ground. As shown in FIGS. 2A and 2B, the buffer amplifier 23 amplifies this and sends out an output signal _S1 . This output signal _S1 is input to the band pass filter 24, and 2 to 20 k
Only the Hz frequency component is output from the filter 24. This output signal S ₂ is amplified by an amplifier 25. This amplified signal S ₃ is input to the first comparator 26 . The first comparator 26 compares the signal S ₃ with a predetermined reference voltage and inputs the signal S ₄ to the integrator 27 . The integrator 27 integrates the deviation signal of the first comparator 26 and inputs the output signal S ₅ to the second comparator 28 . The second comparator 28 compares the signal S ₅ with a predetermined reference voltage and outputs a deviation voltage signal S ₆ to operate an alarm or indicator, and deterioration of the degree of vacuum is detected.

According to the experimental measurement results, the length is 30cm, the cross-sectional area
Connect the 1.25mm ² vinyl coated copper cable to antenna 1.
6, the degree of vacuum at a distance of 1m
When a 6.9kV vacuum shield circuit breaker with a voltage of about 10 ^-1 Torr is opened, a capacitance of 0.2μF is connected to the ground on the load side and a voltage of 6.9/√3≒4kV is applied, for example, and a discharge occurs between the electrodes. did. When this was captured by the antenna 16 and inputted to the detector 18, the signal from the amplifier had an amplitude of 0.6V when the gain was 10,000.

FIG. 6 shows a second embodiment of the present invention when the vacuum shield breaker 1 is in the closed state, and FIG. 7 is an equivalent circuit of the vacuum shield breaker 1 in the closed state. In this second embodiment, a loop-shaped antenna 16a
The antenna 16a is placed near the vacuum shield breaker 1, for example, at a distance of 1 m.
The diameter of the loop part of the antenna 16a is 10 cm, and the length of the straight part is 5 cm.

According to the vacuum level monitoring device of the second embodiment, discharge occurs between the fixed lead 5, the movable lead 7, the fixed electrode 8, the movable electrode 9, and the intermediate shield 10 which is at a floating potential when the vacuum level deteriorates. in this case,
Discharge occurs probably because the specific capacitance between the lead rod and electrode and the intermediate shield is smaller than the apparent capacitance between the electrodes when they are open, or because the capacitance 35 between the intermediate shield 10 and the ground is small. The energy is small and the signal is also small. In this case, as mentioned above, for example, the degree of vacuum at a position 1 m away.
When a voltage of 6.9kV/√3=4kV of about 10 ^-1 Torr was applied, a discharge occurred. When this is captured by the antenna 16a and input to the detector, the signal from the amplifier has a gain
When it was 10000, the amplitude was 0.3V.

FIG. 8 shows a third embodiment of the present invention. Reference numeral 41 denotes a tank in which a vacuum shield and disconnector, which will be described later, is housed, and an insulating medium such as insulating oil or SF ₆ is poured into the tank. The tank 41 is formed of a metal plate such as an iron plate or a stainless steel plate. 42,4
2 is a bushing; 43, 43 are external connection conductors connected to the movable and fixed electrodes of the vacuum shield breaker; and 44 is a frame on which the tank 41 is placed.

A reception antenna 16a is arranged near the external connection conductors 43, 43, and a detector 18 is connected to this antenna 16a via a connection line 17. When a vinyl-coated copper cable with a length of 30 cm and a cross-sectional area of 1.25 mm ² is used as the antenna 16a, the antenna 16a is placed 1 m away from the bushing.
In FIG. 9, a capacitor 46 connected between the vacuum shield breaker 1 and the tank 45 is housed in an insulating oil or gas tank 45. The capacitor 46 has a capacitance of 0.25 μF, and this capacitance is 6.9 kV class and is connected to one of the lead wires.
This is the capacitance equivalent to Km. When the vacuum degree of the vacuum shield breaker 1 is 0.3 Torr, the electrodes are opened and a voltage of 6.9 kV/for example is applied between the external connection conductors 43 and 43.
When a voltage of √3=4kV is applied, a discharge occurs between the electrodes, and the external connection conductor 43,
A signal generated during discharge is transmitted to 43. When a vinyl-coated copper cable with a length of 30 cm and a cross-sectional area of 1.25 mm ² is used as the antenna 16, the antenna 16 is placed 1 m away from the bushing 47 of the fixed conductor, and the signal is received by the antenna 16. ,
It is amplified by the detector 18, and an alarm and display of deterioration of the degree of vacuum are performed.

The amplified signal becomes 0.4V at the above voltage and a gain of 10000.

When the contact is closed, a discharge occurs between the electrode and the lead and the floating potential intermediate shield, but unlike when the contact is opened, the bushing 47 and the external connection conductor 43 are discharged to the outside.
A weak signal goes out into the air through 43. Therefore, the degree of vacuum of the vacuum valve during closing can be checked by connecting the floating intermediate shield of the vacuum shield breaker 1 and the tank wall (earth) with the capacitor 46.
Since a measurable signal is output in the same way as when the electrodes are opened, it is possible to judge whether the degree of vacuum is good or bad.

FIGS. 10 and 11 respectively show still other embodiments of the present invention. In the vacuum level monitoring device shown in FIG. device 48
has a built-in vacuum shield and disconnector (not shown). An external connection conductor 43 protrudes from the outside of this opening/closing device 48 through a bushing 49 . An antenna 16 is arranged near these bushings 49 or external connection conductors 43. Also, the 11th
In the vacuum monitoring device shown in the figure, an antenna 16 and a detector 18 are arranged near a three-phase spacer 50 of a power substation 48. The embodiments shown in FIGS. 10 and 11 also provide the same functions and effects as the embodiments described above.

Conventionally, the quality of the vacuum of the vacuum valve in a tank-type vacuum chamber or disconnector was determined by draining the insulating oil or insulating gas from the oil tank or gas tank, and then measuring the distance between the electrodes of the vacuum valve for a pressure test. The voltage was adjusted and tested using the withstand voltage method. This was extremely time-consuming and caused human error when restoring the original state, but according to the example, the vacuum chamber and disconnector were opened without any manipulation of the oil tank or gas tank, and the vacuum When there is a discharge between the electrodes due to a precursor phenomenon influenced by Patsien's law, or when the fixed lead, fixed electrode, movable electrode, or between the movable lead and the shield are discharged when the contact is closed, the discharge signal output from the pushing and application wires is It is possible to detect vacuum deterioration by receiving a signal with a receiving antenna and electrically processing the signal received by this antenna. Therefore, 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. degree deterioration can be detected accurately.

According to the vacuum level monitoring device in each of the above-mentioned embodiments, it can be applied to vacuum shields and disconnectors that are already in use, and can be applied to most models, including those that are completely earth-shielded. Deterioration of vacuum level can be detected in live line condition. Also,
A commercial power source or a battery may be used as a power source for the detection unit, which is compact and convenient to carry. In addition, the detection sensitivity of vacuum deterioration becomes more detectable when the discharge gap is large because the discharge pressure decreases due to a precursor phenomenon influenced by Patsien's law even in high vacuum, and the pressure value of vacuum deterioration is approximately 10 ^- It ranges from ³ Torr to 100 Torr.

As described above, in the present invention, a detector equipped with an antenna and a bandpass filter for receiving electromagnetic wave signals including high frequencies of 2 to 20 kHz generated during discharge is provided outside the vacuum shield and disconnector. Vacuum shield disconnectors generate internal discharge when the vacuum level deteriorates, and the signals received by this antenna can be electrically processed to detect the vacuum level deterioration, as well as being able to detect external electrical noise. It can be detected with high sensitivity. Furthermore, when detecting vacuum deterioration, there is no need to remove the vacuum shield or disconnector from the circuit, and there is no need to change the structure of the vacuum shield or disconnector or install a separate high-voltage power supply, making it easy and inexpensive to detect vacuum deterioration. can be detected accurately.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a vacuum shield breaker equipped with a vacuum level monitoring device according to a first embodiment of the present invention;
Figure A is a block diagram showing the details of the detection section, Figure 2B is an output diagram of the same as above A, Figure 3 is an equivalent circuit diagram of the vacuum shield disconnector in the shielded state in the first embodiment, 4A, B and 5A, B are operation waveform diagrams of the vacuum shield breaker in the first embodiment, and FIG. 6 is a vacuum level monitoring device according to the second embodiment of the present invention. FIG. 7 is a longitudinal sectional front view of a vacuum shield disconnector, FIG. 7 is an equivalent circuit thereof, and FIG. 8 is a tank-type shield equipped with a vacuum degree deterioration detection device for a vacuum shield disconnector according to a third embodiment of the present invention. FIG. 9 is a front view of a vacuum sheath breaker used experimentally, and FIGS. 10 and 11 are views of a vacuum sheath breaker showing other embodiments of the present invention. FIG. 3 is a front view of the vacuum level monitoring device. 1... Vacuum shield disconnector, 16, 16a... Antenna, 18... Detector, 19... Amplifier, 20...
Judgment department.

Claims (1)

[Claims] 1. In a vacuum shield disconnector that generates an internal discharge when the degree of internal vacuum deteriorates, an antenna is installed near the outside of the vacuum shield disconnector and receives an electromagnetic wave signal generated by the internal discharge, and an electric wire is connected to the antenna. A vacuum degree monitoring device for a vacuum shield and disconnector, characterized by comprising a detector connected to the detector and equipped with a bandpass filter that passes only frequency components from 2kHz to 20kHz.