JPH0288934A - Fluid pressure detector - Google Patents

Abstract

PURPOSE:To realize an inexpensive compact fluid pressure detector by providing an electronic circuit for detecting a quasi-normal or normal pressure and another electronic circuit for detecting an impact pressure in the same container. CONSTITUTION:A partition film 33 is provided to one end of a gas pipeline 32, the other end of which is connected to the tank of a gas insulation switching device and a gas section and fluid section 34 composed of oil, etc., are divided. In addition, a diaphragm 35 is provided to the end section of the pipeline housing the liquid section 34 and a resistance element 37 constitutes a bridge circuit together with a piezoresistance element 36 fitted to the outer side face of the diaphragm 35. An electronic circuit section 80 for measuring the pressure value of a quasi-normal or normal gas which is slow in time responsiveness and a filter circuit 81 which only passes high-frequency signals caused by impact gas pressure are connected to the bridge circuit. Therefore, the gas pressure sensor and earth detecting sensor which are separately provided to each gas division of the gas insulation switching device in conventional method can be integrated and the installing space and cost of this fluid pressure detector can be reduced.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a gas-insulated switchgear that compactly stores power equipment, and is particularly suitable for confirming and monitoring the reliability of such equipment. The present invention relates to a fluid pressure detection device used in a preventive maintenance system.

(Conventional technology) In recent years, due to the need to strengthen substation equipment due to the soaring cost of land and the increase in power supply in urban areas, new road equipment has been developed using SF and gas, which have excellent insulation and arc-extinguishing properties. 2. Description of the Related Art Gas-insulated switchgear, in which substation equipment such as circuit breakers are housed in a sealed container, is environmentally resistant, and has a compact installation volume per V-A, is now in widespread use.

Gas insulated switchgear like the one above is more compact.

Although it has various advantages such as reducing the number of exposed live parts in the grounded tank, it also makes maintenance diagnosis difficult due to higher performance, increases the time required for maintenance and repair work, and significantly reduces reliability if an abnormality occurs inside the container. The disadvantage was that it decreased.

Therefore, in order to improve the reliability of gas-insulated switchgear as a whole, efforts have been made to appropriately design and manufacture the equipment. Confirmation and monitoring are necessary, and various effective means have been studied.

The current problems will be explained with reference to the layout of a typical gas insulated switchgear shown in FIG.

That is, as shown in FIG. 4, a lightning arrester 7. is installed inside the sealed pressure vessel 2. Transformer 8. Earthing switch 9, disconnector 12° current transformer 17
, circuit breaker 18. A bus bar 19 is provided, SF gas is filled as the filling gas 3, and the energizing section 1 and the sealed pressure vessel 2 at ground potential are electrically insulated.

In addition, in order to arrange the bus bar 19 inside the sealed pressure vessel 2,
Insulating spacers 11 are arranged at appropriate intervals to maintain the mechanical strength and dielectric strength of the bus bar 19.

Further, the main circuit is connected to the disconnector 12 through the bushing 1.
It is connected to a transformer 20 via a circuit breaker 18. Although FIG. 4 shows a single-line power receiving circuit, power may be supplied to the transformer 20 via the disconnector 12 from a power receiving main circuit (not shown on the right side of FIG. 4).

On the other hand, the gas insulated switchgear is controlled by a switchboard 15, the voltage element is obtained by the transformer 8, the current element is obtained by the current transformer 17, and the main circuit switching and breaking operations are carried out via the operation cubicle 14. This is done by applying an energizing signal to the operating device 13 of the type (disconnector, circuit breaker, earthing switch).

Further, as a mechanical drive source for the switches, a predetermined pressure (generally 15 kg/cd, for example) is obtained from the compressor equipment 16 and supplied to the operating device 13 via the operating cubicle 14 .

On the other hand, the insulating spacer 11 also has the function of sealing the filling gas due to separation for maintenance and arrangement, so the SF is inserted through the valve 4.

Each compartment is filled with SF and gas from a gas cylinder 6 via a gas cubicle 5, and the pressure can also be detected from the gas cubicle 5.

In the conventional gas insulated switchgear having the above-mentioned configuration, the characteristics of SF and gas make it possible to downsize the storage equipment, thereby achieving downsizing as a whole. (
The volume occupied by each KV-A is reduced, allowing for effective use of the installation site. ) Also, two stages ~ using a gas bus bar
Since a three-tiered stacking configuration is possible and the blocks are stacked, there is an advantage that a large volume configuration can be achieved with a small area.

Additionally, since the sealed pressure vessel is grounded.

There is no risk of electric shock even if you come close to the device while power is being applied, and the power-applying section is not directly exposed to environmental disturbances such as salt damage or wind and rain, so it will not be affected.

In addition, various switches are made of SF with high arc extinguishing ability.

Since arc treatment is performed in gas, there is also the advantage that the breaking capacity per main contact can be significantly improved.

On the other hand, although it has the above-mentioned advantages, it also has the following disadvantages.

In other words, by making the entire gas-insulated switchgear more compact, there are fewer dimensional restrictions for disassembly or reassembly work when maintaining and inspecting storage equipment, which increases the time required for maintenance and inspection work and significantly reduces work efficiency. was.

In addition, the SF and gas sealed inside the container are expensive, and the manufacturing technology to prevent gas leakage to the outside is high-grade, and due to its good insulation, ν/m is large, so the drop in gas pressure is caused by the insulation margin. Due to the sensitive nature of the gas leak, repair of the gas leak was an urgent matter.

Furthermore, since a sealed pressure vessel is used, there is a problem in that the stored equipment cannot be visually monitored.

In addition, replacement work due to wear and tear on the main contacts of various switching devices,
It also has the drawback that it takes a lot of time to recover and refill the SF and gas, and the gas insulated switchgear has to be stopped for a long time.

Compared to the advantages and disadvantages explained above, gas insulated switchgear has become popular in terms of performance because it has great advantages and disadvantages.However, as the number of installation locations increases and mass production begins, maintenance and Variations in the preparation and quality of emergency repair systems are also a problem that cannot be ignored.

As a countermeasure against this, there is a strong desire to establish a preventive maintenance system that can reliably confirm that the operating state is normal and that can detect and monitor early when an abnormality occurs.

By introducing such a preventive maintenance system, accidents in gas-insulated switchgear can be prevented, and economic losses caused by stable power supply and accidents can be eliminated.

By the way, in the above-mentioned preventive maintenance system, by quickly locating the accident point, it is possible to hasten accident response and early recovery, and at the same time, it is possible to efficiently operate the substation in the event of an accident and to reduce the scope of the accident. In order to minimize this, ground fault detectors are often used in addition to gas pressure sensors.

FIG. 5 shows an example of a conventionally used gas pressure sensor for detecting quasi-steady or steady pressure. That is, a partition membrane 33 is disposed at the other end of the gas pipe 32, one end of which is connected to the tank of the gas insulated switchgear, to separate a gas portion from a liquid portion 34 made of oil or the like. Further, a diaphragm 35 made of stainless steel or the like is disposed at the end of the pipe in which the liquid portion 34 is housed, and a piezoresistive element 36 is provided on the outer surface of the diaphragm 35 for converting the distortion of the diaphragm 35 into an amount of change in resistance. is attached, and forms a bridge circuit together with the resistive element 37.

Further, an electronic circuit 38 for amplifying the signal is connected to the bridge circuit, and an electrical-to-optical conversion circuit 39 converts the signal amplified by the electronic circuit 38 into an optical signal, and connects the optical connector 40 and the optical cable 41. is transmitted to the receiver side via Note that 42 is a battery for the electronic circuit 38 and the electric-optical conversion circuit 39.

This kind of gas pressure sensor is used to measure static pressure, and in order to improve the accuracy and stability of the sensor output, the time response is generally slow at several seconds, so the number of rises that occur during a ground fault is small. It cannot be applied to detect shock gas pressure within ms.

On the other hand, an impact gas pressure sensor as shown in FIG. 6 has been used as a ground fault detection sensor for detecting the impact gas pressure generated at the time of a ground fault.

That is, a gas insulated switchgear 61 which has a high voltage charging part built into a container filled with insulating gas, and a switch case 52 of a shock gas pressure detector are connected via a communication pipe 53. . Further, the switch case 52 includes:
A gas introduction hole 54 is formed at the bottom, and the inside thereof is a gas chamber 57 provided with a cylinder 55 and a detection switch 56 such as a microswitch. This cylinder 55 is installed vertically on the bottom surface of the switch case 52, its lower opening communicates with the gas introduction hole 54, and its upper part is connected to the end plate 55.
It communicates with the gas chamber 57 through the through hole 59 of No.8. The detection switch 56 is fixed to the extension of the end plate 58.

Further, the cylinder 55 has a float 50 having a protrusion 51.
is installed so that it can move up and down.

In such a conventional impact gas pressure sensor, when the gas insulated switchgear is in operation, the gas chamber 57 of the switch case 52 receives insulating gas from the gas insulated switchgear 61 through the communication pipe 53. Gas introduction hole 54. It is introduced through the cylinder 55 and maintained at a constant pressure.

However, when a ground fault occurs in the gas insulated switchgear 61, the internal pressure inside the container increases, and the float 50 floats due to the difference between the pressure transmitted to the cylinder 55 and the pressure inside the gas chamber 57 of the switch case. death.

The detection switch 56 is activated via the protrusion 51. Then, the detection switch 56 opens and closes a detection circuit (not shown),
Displays a fault.

However, the ground fault detection sensor as shown in Figure 6
Since the size is very large and the switch case 52 is required to withstand a certain gas pressure, the weight of the device is very large and the cost is also high.

Furthermore, both the gas pressure sensor and the ground fault detection sensor must be installed in each of the plurality of gas division areas of the gas insulated switchgear, resulting in a very large installation space.

(Problems to be Solved by the Invention) As described above, when detecting fluid pressure using both a conventional gas pressure sensor and a ground fault detection sensor, the installation space of the device increases and the cost also increases. It was expensive.

Therefore, the present invention was proposed to eliminate the above-mentioned drawbacks, and its purpose is to provide an inexpensive and compact fluid pressure detection device capable of detecting both quasi-steady or steady gas pressure and shock gas pressure. Our goal is to provide the following.

[Structure of the invention]

(Means for Solving the Problems) The fluid pressure detection device of the present invention has an electronic circuit for detecting quasi-steady or steady pressure and an electronic circuit for detecting impact pressure disposed in the same container, and the respective signals are is converted into an optical signal and transmitted to a receiver.

(Function) The fluid pressure detection device of the present invention has an electronic circuit for detecting quasi-steady or steady pressure and an electronic circuit for detecting impact pressure that are arranged in the same container. The gas pressure sensor and the ground fault detection sensor, which were previously installed separately in each gas section, are integrated, making it possible to reduce the installation space and cost of the device.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIG. Note that the same members as those of the conventional type shown in FIGS. 5 and 6 are designated by the same reference numerals, and the description thereof will be omitted.

Structure of Umbrella Embodiment In this embodiment, as shown in FIG. A liquid portion 34 made of oil or the like is separated. A diaphragm 35 made of stainless steel or the like is disposed at the end of the pipe in which the liquid portion 34 is housed, and a piezoresistive element is mounted on the outer surface of the diaphragm 35 to convert distortion of the diaphragm 35 into a resistance change amount. 36 is attached, and together with the resistive element 37, a bridge circuit is constructed.

The bridge circuit also includes an electronic circuit section (amplifier) 80 for measuring quasi-steady or steady gas pressure values with slow time response.
A filter circuit 81 is connected to the filter circuit 81 that allows only high frequency signals caused by the impact gas pressure to pass through.

FIG. 2 shows an example of measurement of an impact gas pressure wave generated by a ground fault arc, and it can be seen that the rise of the pressure wave is about several Ils. Therefore, if the characteristics of the filter circuit 81 in FIG. 1 are such that only signals of such frequencies are allowed to pass, detection sensitivity and S/N ratio can be improved. The signal of the filter circuit 81 is sent to the amplifier 82
After passing through the peak hold circuit, the DC No. 43 is held for a certain period of time, and then modulated by the modulation circuit 84 at a frequency in a region different from that of the pressure signal in a steady or quasi-steady state, and then sent to the receiver as an optical signal. transmitted to.

Function of Umbrella Embodiment Umbrella In the fluid pressure detection device of this embodiment having such a configuration, an electronic circuit for measuring impulse gas pressure is provided in parallel with an electronic circuit for measuring quasi-steady or steady gas pressure. Since the structure is configured so that signals can be transmitted independently to the receiver side, it is possible to measure quasi-steady or steady gas pressure and detect ground faults with a single sensor unit, and the conventional large sensor can be used for gas-insulated switching. There is no need to separately attach it to the device body. As a result, it is possible to downsize the device.

Cost reduction can also be achieved.

Note that the electronic circuit for ground fault detection does not need to measure the absolute value of the signal; it only needs to detect the presence or absence of the signal.
The circuit configuration may be simple, consisting of a simple amplifier, a peak hold circuit, etc.

FIG. 3 shows another embodiment of the invention. In this embodiment, the steady or quasi-steady state gas pressure signal and the impulse gas pressure wave signal are converted into optical signals of different wavelengths by the electro-optical converter 39.85, and then combined by the combiner 86. .

The signal is transmitted via a single-core optical cable 41 via an optical connector. In this case, if the receiver is provided with a demultiplexer that demultiplexes different and identical signals, the signals can be easily separated.

〔Effect of the invention〕

As described above, according to the present invention, an electronic circuit for detecting quasi-steady or steady pressure and an electronic circuit for detecting impact pressure are arranged in the same container, and their respective signals are converted into optical signals. It is possible to provide an inexpensive and compact fluid pressure detection device capable of detecting both quasi-steady or steady gas pressure and impulse gas pressure by the simple means of transmitting the pressure to a receiver.

[Brief explanation of the drawing]

11th! I is a configuration diagram of a fluid pressure detection device showing one embodiment of the present invention, FIG. 2 is a shock gas pressure waveform diagram, and FIG. 3 is a configuration diagram of a fluid pressure detection device showing another embodiment of the invention. 4
The figure is a gas system diagram of a general gas insulated switchgear, 5th FM
is a configuration diagram showing a conventional gas pressure sensor, and Fig. 6 is a conventional ? #It is a sectional view showing a percussion gas pressure sensor. 1... Bushing, 2... Sealed pressure vessel, 3
...Filling gas, 4...Valve. 5.Bagaski vehicle, 6.Gas cylinder, 7..
・Surge arrester, 8.--Transformer. 9...Earthing switch, 11...#! ! Edge spacer 2...Disconnector, 13...Operator, 14
... Cubicle, 15... Switchboard, 16...
Compressor equipment, 17...Current transformer. 18... Circuit breaker, 19... Bus bar. 20...Transformer, 31...Case, 32...
...Gas piping, 33...Partition membrane. 34...Liquid part, 35...Diaphragm,
36... Piezoresistance element, 38... Electronic circuit, 40... Optical connector, 42... Battery. 51...Protrusion, 53...Communication pipe, 55...Cylinder, 57...Gas chamber, 59...Through hole. 80...Amplifier, 82...Amplifier, 84...Modulation circuit, 86...Synthesizer.

Claims (1)

[Claims] In a fluid pressure detection device consisting of a pressure detection sensor section that converts fluid pressure into an electrical signal and a circuit section that amplifies and transmits the signal, the pressure sensor signal is converted into an electronic circuit that detects quasi-steady or steady pressure, and an electronic circuit that detects impulsive pressure. A fluid pressure detection device characterized in that the output of the pressure sensor is branched into an electronic circuit for detection, and the output of the pressure sensor is introduced into the latter electronic circuit via a high-pass filter or a band-pass filter.