JP2672663B2 - Preventive maintenance system - Google Patents

Description

Description: [Object of the invention] (Field of industrial application) The present invention relates to a gas-insulated switchgear in which power equipment is compactly housed, and is particularly suitable for checking and monitoring the reliability of each equipment. It concerns a preventive maintenance system.

(Prior art) In recent years, due to the need to strengthen substation equipment accompanying the skyrocketing of land and the increase in power supply in urban areas, SF ₆ gas, which has excellent insulation and arc extinguishing properties, has been used to The so-called gas-insulated switchgear, in which transformers such as circuit breakers are housed in a closed container and the environmental resistance and the installation volume per KV · A are made compact, has become widespread and in operation.

Although the gas insulated switchgear as described above has various advantages such as downsizing and reduction of the exposed charging part of the grounding tank, it is difficult to perform maintenance diagnosis due to high performance, and the maintenance and repair work time is increased. In the case where an abnormality occurs, there is a disadvantage that the reliability is significantly reduced. Therefore, in order to improve the reliability of the entire gas insulated switchgear,
Although efforts are being made to properly design and manufacture the device, it is necessary to confirm and monitor the reliability of the entire device as part of improving the quality of the power supply capability, and various effective means have been studied.

Here, the problems at the present time will be described with reference to a layout diagram of a typical gas-insulated switchgear as shown in FIG. That is, the sealed pressure vessel 1 is set to the ground potential, and the lightning arrester 2, the transformer 3, the grounding switch 4, the disconnector 5, the current transformer 6, the circuit breaker are provided in the sealed pressure vessel 1 as a voltage applying section. 7 and the busbar 8 are arranged, and the sealed pressure vessel 1 and the charging section which are set to the ground potential are SF ₆ enclosed in the sealed pressure vessel 1.
It is electrically insulated by an insulating gas 9 such as a gas. In the sealed pressure vessel 1, insulating spacers 10a to 10d are provided at appropriate intervals to support the busbar 8, so that the mechanical strength and the dielectric strength of the busbar 8 can be maintained. . The insulating spacers 10a to 10d are arranged so as to airtightly divide the space inside the sealed pressure vessel 1 from the necessity of separation and maintenance for the maintenance and arrangement. The gas is sealed in each of the divided areas. In the figure, reference numeral 11 denotes a gas cylinder, and the gas cylinder 11 is configured to be filled with gas through the gas cubicle 12 and the valve 13 into each of the divided regions in the sealed pressure vessel 1. Note that the gas cubicle 12 also has a function of detecting the pressure in each of the divided areas.

Further, in FIG. 3, the main circuit is connected to the transformer 19 via the pushing 14, the disconnector 5 and the circuit breaker 7. Although FIG. 3 shows a single-line power receiving main circuit, power is supplied from the power receiving main circuit (not shown) on the right side of the power receiving main circuit to the transformer 19 via the disconnector 5. In some cases. On the other hand, reference numeral 15 in the figure is a switchboard, which gives an urging signal to the operating device 17 of the switches (disconnector 5, circuit breaker 7, grounding switch 4) via the operation cubicle 16 and supplies the main circuit of the switches. It has the function of controlling switching and shut-off operations. Further, in the figure, reference numeral 18 denotes a compressor equipment 18 which is a drive source of the switches, and a predetermined pressure (for example, 15 kg / cm ² is generally obtained) obtained by the compressor equipment 18 is
It is configured to be supplied to the operation device 17 via the operation cubicle 16 to operate the switches.

The gas-insulated switchgear having the above structure has the following advantages. That is, due to the excellent characteristics of the insulating gas, the size of the storage device can be reduced, and the overall size of the device can be reduced. In other words, KV
The occupied volume per A becomes small, and the effective use of the installation site becomes possible. In addition, the gas bus bar can be used to form a stacking structure of two to three steps, and block stacking can be performed, so that there is an advantage that a large volume structure can be obtained with a small area. Furthermore, since the sealed pressure vessel 1 is grounded, there is no risk of electric shock even when approaching during power application, and since the power application unit is not directly exposed to salt damage, wind and rain, deterioration due to external factors may occur. There is no fear. In addition, various switches,
Since arc processing is performed in SF ₆ gas with high arc extinguishing ability, 1
The breaking capacity per main contact can be greatly improved.

By the way, the gas-insulated switchgear shown in FIG. 3 has the above-mentioned advantages, but has the following drawbacks. That is, as a result of downsizing the entire gas insulated switchgear, the size of the rotation work or reassembly work is limited to a small size during maintenance and inspection of the storage equipment, and the maintenance and inspection work of the storage equipment requires a long time. , The working efficiency was significantly reduced. In addition, since insulating gas such as SF ₆ gas sealed inside the sealed pressure vessel is expensive,
As the production technology for preventing gas leakage to the outside becomes high-grade, kv / mm is large due to good insulation properties, and since the gas pressure drop is very sensitive to insulation margin, a complete emergency repair system for gas leakage is completed Had been requested. Furthermore, since the sealed pressure vessel is used, there is a disadvantage that the storage device cannot be monitored visually. Also, in replacement work due to exhaustion of the main contacts of various switchgear, it takes a lot of time to recover and refill the insulating gas, so the gas-insulated switchgear will be stopped for a long time, hindering stable power supply. There was also a disadvantage of causing

As described above, the gas-insulated switchgear shown in FIG. 3 has not only advantages but also some drawbacks. However, the performance advantage is not enough even if the drawbacks are compensated. Therefore, it is remarkably popular. However, recently, the number of installation locations of the gas insulated switchgear has increased, and the mass production system has been adopted. As a result, there is a problem that the maintenance and the emergency repair system are not negligible in the preparation and quality variation.

As a countermeasure against such a problem in the gas insulated switchgear, it is desired to establish a preventive maintenance system capable of confirming the reliability that the operating condition is normal and capable of early detection and monitoring when an abnormality occurs. That is, it is expected that the introduction of such a preventive maintenance system will prevent accidents in the gas-insulated switchgear in advance, ensure a stable power supply, and minimize the economic loss due to the accident. .

By the way, in the preventive maintenance system as described above,
By detecting the accident point as soon as possible, the accident response can be accelerated.
Along with the steady gas pressure sensor, a ground fault detector (impact gas pressure sensor) is provided for the purpose of contributing to early recovery, efficiently applying substations in the event of an accident, and minimizing the ripple range of the accident. ) Is often used.

FIG. 4 shows an example of a conventional steady-state gas pressure sensor that detects a quasi-steady state or a steady state pressure. That is, the gas pipe 22 is drawn out from the inside of the case 21, and the end (not shown) is connected to the tank of the gas insulated switchgear. Further, a liquid chamber 24 is arranged at an end portion of the gas pipe 22 inside the case 21 via a partition film 23 having elasticity, and the partition film 23 allows the gas pipe 22
And the liquid (oil or the like) in the liquid chamber 24 are separated. A diaphragm 25 made of stainless steel or the like is provided on the liquid chamber 24 on the side opposite to the partition film 23, and a piezo for converting distortion of the diaphragm 25 into a resistance change amount is provided on the outer surface of the liquid chamber of the diaphragm 25. A resistance element 26 is mounted, and the piezo resistance element 26 and the resistance element 27 constitute a bridge circuit. An electronic circuit 28 for amplifying the signal and an electric / optical conversion circuit 29 for converting the amplified signal into an optical signal are sequentially connected to the bridge circuit, and the electric / optical conversion circuit 29 penetrates the case 21. Optical connector 30 and optical cable arranged outside the case
It is connected to the receiver side via 31. In addition, in FIG.
Reference numeral 32 denotes a battery of the electronic circuit 28 and the electric / optical conversion circuit 29.

In the steady gas pressure sensor configured as described above,
When the gas pressure in the gas pipe 22 changes due to the change in the gas pressure in the tank of the gas insulated switchgear, this pressure change causes the partition membrane 23, the liquid in the liquid chamber 24 and the diaphragm 25.
After being converted into a resistance change amount by the piezoresistive element 26, amplified by the electronic circuit 28 and converted into an optical signal by the electrical / optical conversion circuit 29, the optical connector 30 and the optical cable 31
And transmitted to the receiver side. Such a steady gas pressure sensor is for measuring static quasi-steady or steady pressure, and its time response is the accuracy of the sensor output,
In order to improve the stability, the setting is generally as slow as about several hundred msec. On the other hand, since the rise of the impact gas pressure generated at the time of the ground fault is several msec or less, which is an extremely short time, it is difficult to apply the gas pressure sensor to detect such an impact gas pressure.

On the other hand, an impact gas pressure sensor as shown in FIG. 5 is used as a ground fault detector that detects the impact gas pressure generated during a ground fault. That is, in the figure, reference numeral 41 denotes a gas-insulated switchgear having a high-voltage charging unit built in a sealed pressure vessel. The gas-insulated switchgear 41 and the switch case 42 of the shock gas pressure sensor are connected to a communication pipe 43. Connected through. A gas introduction hole 44 is formed at the bottom of the switch case 42 and is connected to the communication pipe 43.A gas chamber having a cylinder 45 and a detection switch 46 such as a micro switch is provided inside the switch case 42. It is 47.
The cylinder 45 is vertically installed on the bottom surface of the switch case 42, the lower opening thereof communicates with the gas introduction hole 44, and the upper opening thereof passes through the through hole 49 of the end plate 48 to form the gas chamber.
It is connected to 47. The detection switch 46 is fixed to an extension of the end plate 48. A float 50 is vertically movably attached to the hollow portion of the cylinder 45, and a protrusion 51 for pressing the detection switch 46 is provided on the float 50.

The operation of the thus configured impact gas pressure sensor is as follows. That is, during the steady operation of the gas insulated switchgear 41, the insulating gas from the gas insulated switchgear 41 is introduced into the gas chamber 47 of the switch case 42 through the communication pipe 43, the gas introduction hole 44, and the cylinder 45, The gas chamber 47 is maintained at a steady pressure. However, when a ground fault occurs in the gas insulated switchgear 41, the internal pressure in the container increases,
Due to the pressure transmitted to the cylinder 45 and the pressure difference in the gas chamber 47 of the switch case 42, the float 50 in the cylinder 45
Comes up and activates the detection switch 46 via the protrusion 51,
The detection switch 46 is configured to open and close a detection circuit (not shown) to display a failure.

Further, in the conventional preventive maintenance system, as shown in FIG. 6, the gas pressure sensor as described above is provided for each gas compartment.
Both the 60 and the shock gas pressure sensor 61 for detecting the accident point were provided.

(Problems to be solved by the invention) However, in the conventional preventive maintenance system as described above, since both the gas pressure sensor 60 and the impact gas pressure sensor 61 must be installed for each gas section, The installation space becomes very large,
The installation space for the entire gas-insulated switchgear was also increasing.
Further, since the impact gas pressure sensor 61 as shown in FIG. 5 has a very large size and requires a switch case 42 having a mechanical strength enough to withstand a predetermined gas pressure, the device There are drawbacks that the whole weight becomes very large and the cost becomes high.

The present invention has been proposed to solve the above drawbacks, and its purpose is to match the gas capacity of each gas compartment,
By efficiently arranging the gas pressure sensor and the impact gas pressure sensor, it is possible to downsize the gas insulated switchgear,
It is to provide an economical preventive maintenance system.

[Structure of the Invention] (Means for Solving the Problems) The preventive maintenance system of the present invention is a gas-insulated device in which an insulating gas is housed in a grounded metal container together with a high-voltage conductor, and is determined by the condition at the time of a ground fault. A gas pressure sensor is arranged in a gas compartment having a specific gas capacity or less, and both a gas pressure sensor and an impact gas pressure sensor are arranged in a gas compartment having a larger gas capacity. Is.

(Operation) According to the preventive maintenance system of the present invention, in a gas section having a specific gas capacity or less determined by the condition at the time of a ground fault, the gas pressure sensor detects a quasi-steady increase in gas pressure, thereby The occurrence of an accident in a compartment can be detected, and in a gas compartment having a higher gas capacity, both the gas pressure sensor and the impact gas pressure sensor can be used to detect the occurrence of an accident in that gas compartment.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to FIGS. 1 and 2. The same members as those of the conventional type shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, as shown in FIG. 1, a gas pressure sensor 60 is provided in each of the gas compartments surrounded by the two-dot chain line and having a small gas capacity other than the main bus bar.
Both the gas pressure sensor 60 and the impact gas pressure sensor 61 are arranged in the main bus bar portion having a large container volume and a large gas capacity.

In the preventive maintenance system of this embodiment having such a configuration, the accident point in each gas compartment is detected as described below.

That is, generally, the quasi-steady gas pressure increase due to the arc generated in the tank at the time of an accident can be evaluated by the following formula, as studied by CIGRE WG and the like.

△ P = (C ・ I ・ t) / V △ P: Pressure rise value (Kg / cm ² ) C: Coefficient (0.2 to 0.35) I: Arc current (KA) t: Arc duration (ms) V: Container Volume () The fault current is almost determined by the position of the substation on the power system. Further, the arc duration is roughly determined by the operating time of the protection relay and the current interruption time of the circuit breaker. Therefore, if the volume of each gas compartment is determined, the gas pressure increase value ΔP at the time of an accident in each gas compartment can be evaluated.

On the other hand, the resolution of the gas pressure sensor is generally about 0.01 Kg / cm ² , but the lower limit value ΔPmin of the detectable pressure rise value is determined from the resolution of such a sensor and the processing system. If ΔP> ΔPmin, the gas section can detect an accident by the gas pressure sensor 60,
The impact gas pressure sensor can be omitted. Also, △
In the gas section of P ≦ ΔPmin, it is difficult to detect an accident by the gas pressure sensor. In this case, when an arc is generated in the tank, it causes several KHz as shown in Fig. 2.
A certain amount of pressure wave is generated in the tank and propagates in the tank at the speed of sound. It has been experimentally confirmed that this pressure wave is not significantly affected by the amount of gas and has almost no attenuation. Therefore, by applying the impact gas pressure sensor 61 in the gas section of ΔP ≦ ΔPmin, the accident in the gas section can be detected.

As described above, according to this embodiment, the number of sensors to be installed can be reduced by changing the sensors to be installed according to the gas capacity of each gas compartment, so that the installation space can be reduced. Becomes Further, accident detection can be efficiently performed in each gas section.

[Effects of the Invention] As described above, according to the present invention, a gas pressure sensor is provided in a gas section having a specific gas capacity or less determined by the condition at the time of a ground fault, and a gas having a gas capacity higher than that is provided. By the simple means of disposing both the gas pressure sensor and the impact gas pressure sensor in the compartment, it is possible to downsize the gas insulated switchgear and to provide an economical preventive maintenance system.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the preventive maintenance system of the present invention. A gas section diagram of a substation showing a sensor mounting position, FIG. 2 is a pressure waveform diagram when a ground fault arc occurs, and FIG. Fig. 4 is a sectional view showing a steady gas pressure sensor, Fig. 5 is a sectional view showing an impact gas pressure sensor, and Fig. 6 is a sensor mounting position in a conventional preventive maintenance system. FIG. 3 is a gas section diagram of the substation showing FIG. 1 ... sealed pressure vessel, 2 ... lightning arrester, 3 ... transformer, 4
… Installation switchgear, 5… Disconnector, 6… Current transformer, 7…
Circuit breaker, 8 ... bus, 9 ... insulating gas, 10a to 10d ... insulating spacer, 11 ... gas cylinder, 12 ... gas cubicle, 13 ... valve, 14 ... bushing, 15 ... switchboard,
16… Operation cubicle, 17… Operation device, 18… Compressor equipment, 19 …… Transformer, 21 …… Case, 22 …… Gas piping, 23 …… Partition membrane, 24 …… Liquid chamber, 25 …… Diaphragm, 26 ... Piezoresistive element, 27 ... Resistance element, 28 ... Electronic circuit, 29 ... Electric / optical conversion circuit, 30 ... Optical connector,
31 …… Optical cable, 32 …… Battery, 41 …… Gas insulated switchgear, 42 …… Switch case, 43 …… Communication pipe, 44 ……
Gas inlet hole, 45 …… Cylinder, 46 …… Detection switch, 47
…… Gas chamber, 48 …… End plate, 49 …… Through hole, 50 …… Float, 51 …… Pole, 60 …… Gas pressure sensor, 61 …… Impact gas pressure sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-262025 (JP, A) JP-A-2-23009 (JP, A) JP-A-2-206322 (JP, A) JP-A-2- 266238 (JP, A) Actually opened 63-135246 (JP, U)

Claims (1)

(57) [Claims] 1. A gas insulation device in which an insulating gas is housed in a grounded metal container together with a high-voltage conductor, and a gas pressure sensor is provided in a gas compartment having a specific gas capacity or less determined by a ground fault condition. A preventive maintenance system characterized in that both a gas pressure sensor and an impact gas pressure sensor are provided in a gas compartment having a gas capacity larger than that.