Diagnostic device for gas-insulated power equipment and diagnostic method for gas-insulated power equipment

Abstract

According to an embodiment of the present invention, a diagnostic device for gas-insulated power equipment has a cracked gas detecting means. The gas-insulated power equipment has a sealed container, a conductor, and an insulating gas. The sealed container is partitioned into a plurality of measurement areas. The conductor is disposed inside the sealed container. The insulating gas is a gas containing CO2 or O2 and filling the inside of the sealed container to insulate the conductor. The cracked gas detecting means detects whether O3 is present in the insulating gas in a measurement area of the sealed container.

Description

Diagnostic device for electric power gas-insulated equipment and diagnostic method for electric power gas-insulated equipment

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a diagnostic device for electric power gas insulated equipment and a diagnostic method for electric power gas insulated equipment.

[0002] There are various types of gas-insulated electrical equipment, such as load break switches, disconnecting switches, earthing devices, circuit breakers, gas-insulated switchgear (GIS), gas-insulated busbars, gas-insulated power transmission pipelines, and gas-insulated transformers, depending on the purpose of use and the functions required.

[0003] A gas-insulated power transmission pipeline, a type of gas-insulated equipment for electric power, comprises a sealed, hollow, cylindrical container and a conductor for carrying high-voltage current. The conductor is placed inside the container. The container is filled with insulating gas. A gas-insulated power transmission pipeline is designed so that the insulating properties of the conductor are maintained by the insulating gas filled inside the container. The container is made of metal or a solid insulator. A metal container is grounded. A solid insulator container is made of ceramics, resin, or the like.

[0004] Circuit breakers and disconnecting switches, which are types of gas-insulated electrical equipment, have the function of switching current on and off. These have openable and closable contacts located midway along a conductor insulated by insulating gas. When the current is interrupted, the contacts are released. When the contacts are released, an arc discharge occurs in the insulating gas. The generated arc is extinguished within the insulating gas, thereby interrupting the current.

[0005] The insulating gas used in gas-insulated electrical equipment is generally SF ６ A gas containing SF is used. ６ has excellent insulating properties for high voltage currents and arc extinguishing properties. ６ By using this as the insulating gas, it is possible to make gas insulated electrical equipment smaller, and to provide economical gas insulated electrical equipment.

[0006] science fiction ６ is a gas that is very suitable as a medium for insulating high voltage current and extinguishing arcs. ６It has become clear that CO has a high global warming effect. The magnitude of global warming effect is generally measured by the global warming potential, or CO ２ It is expressed as a relative value when the global warming potential of SF is set to 1. ６ It is known that the global warming potential of SF is as high as 25,200. ６ It is desirable to reduce the amount of

[0007] Therefore, CO is used as an insulating gas in gas-insulated electrical equipment. ２ Ya O ２ It is considered to use gases containing oxygen atoms, such as CO ２ Global warming is a science fiction ６ It is very small, 1 / 25,200 of the O ２ has zero global warming effect. ６ Instead of CO ２ Ya O ２ It is believed that by applying this to the insulating gas in gas-insulated electrical equipment, it will be possible to significantly reduce the impact on global warming.

[0008] On the other hand, CO ２ Ya O ２ The arc extinguishing and insulating performance of SF ６ However, it is inferior to SF. ６ Compared to air, which was used as an insulating medium and arc-extinguishing medium in gas-insulated electrical equipment before CO ２ Ya O ２ is known to have excellent arc extinguishing performance. ２ Ya O ２ It is known that the insulating performance of CO is equal to or better than that of air. ２ , O ２ The gas containing oxygen atoms such as SF ６ By using it instead of gas, it will be possible to provide gas-insulated electrical equipment that is compact, environmentally friendly, and has a reduced impact on global warming.

[0009] Incidentally, in gas-insulated equipment for electric power, partial discharges caused by insulation defects are detected inside the equipment to discover abnormalities before they lead to serious breakdowns. The occurrence of partial discharges inside the equipment suggests that there is a local insulation defect, although it does not lead to a total breakdown. Therefore, if partial discharges can be detected, abnormalities in gas-insulated equipment for electric power can be quickly recognized. When the insulating gas is SF ６ If so, then SO ２ It was determined that partial discharge had occurred by detecting the occurrence of SF. ６ Instead of CO ２ or O ２ A means for detecting partial discharge is also required in gas-insulated electrical equipment that uses a gas containing HCl as the insulating gas.

[0010] Patent No. 4660407

[0011] The problem to be solved by the present invention is to provide a diagnostic device for electric gas insulated equipment and a diagnostic method for electric gas insulated equipment that can detect the occurrence of partial discharge inside the equipment due to insulation failure and diagnose the functional maintenance state.

[0012] A diagnostic device for gas-insulated electrical equipment according to an embodiment includes a decomposition gas detection means. The gas-insulated electrical equipment includes a sealed container, a conductor, and insulating gas. The sealed container is partitioned into a plurality of measurement regions. The conductor is disposed inside the sealed container. The insulating gas is CO2 gas filled inside the sealed container to insulate the conductor. ２ or O ２ The decomposition gas detection means detects O in the insulating gas in the measurement area of ​​the sealed container. ３ Detect whether it contains

[0013] 1 is a schematic diagram illustrating the internal structure of a conventional single-phase gas-insulated power transmission line as an example of electric power gas-insulated equipment, and a state in which partial discharge occurs. 2 is a schematic diagram illustrating a single-phase gas-insulated power transmission line as an example of electric power gas-insulated equipment, and a diagnostic device for electric power gas-insulated equipment, which is a first embodiment. 3 is a schematic diagram illustrating a gas-insulated switchgear as an example of electric power gas-insulated equipment, and a diagnostic device for electric power gas-insulated equipment, which is a second embodiment. 4 is a schematic diagram illustrating HF, CO, and O in an insulating gas.３ Graph showing the change in concentration of O ３ 10 is a graph illustrating a decay time. 11 is a schematic diagram illustrating a single-phase gas-insulated power transmission line as an example of gas-insulated equipment for electric power according to a third embodiment, and a diagnostic device for gas-insulated equipment for electric power according to the third embodiment.

[0014] Fig. 1 shows a typical gas-insulated power transmission line, which is a type of conventional gas-insulated equipment for electric power. The gas-insulated power transmission line shown in Fig. 1 comprises a sealed, hollow cylindrical sealed container 1 and a conductor 2 disposed inside the sealed container 1 for carrying a high-voltage current. The sealed container 1 is filled with insulating gas. The insulating gas is SF ６ Standalone or SF ６ It is a mixed gas containing SF ６ The mixed gas containing, for example, SF ６ and N ２ Mixture of SF ６ and CF ４ For example, if a needle-like minute foreign particle 4 is present near the conductor 2, a partial discharge 5 will occur originating from the minute foreign particle 4. If this state is left unchecked, it will lead to a breakdown discharge 6 that short-circuits the entire circuit, causing the loss of functionality of the gas-insulated equipment for electric power.

[0015] Insulating gas is SF ６ Standalone or SF ６ When a partial discharge occurs in a gas-insulated electrical equipment, the detection of partial discharge in the case of a mixed gas containing SO ２ Therefore, the insulating gas in the sealed container 1 is analyzed using a gas detector tube or gas sensor, and the amount of SO ２ By detecting specific decomposition gases such as the above, it has been possible to know that some kind of discharge has occurred inside the sealed container 1.

[0016] However, SO ２ Decomposition gases such as SO are not only generated in abnormal partial discharges. ２ Decomposition gases such as SO are also generated by arc discharge when current is switched normally in a circuit breaker or disconnector. ２Even if decomposition gases such as these are detected, this does not necessarily provide a basis for determining that abnormal partial discharge is actually occurring.

[0017] In addition, from the perspective of preventing global warming, ６ Instead of CO ２ or O ２ When these elements or mixed gases containing these elements are used as insulating gases, it is not clear what kind of gas should be detected to detect the occurrence of abnormal discharge.

[0018] On the other hand, there is a technology in which an antenna for detecting electromagnetic waves is provided beforehand inside or outside the sealed container 1, and the electromagnetic waves generated by partial discharge are detected by the antenna, thereby detecting that some kind of discharge is actually occurring inside the sealed container 1. However, detecting partial discharge using an antenna carries the risk of false detection due to electrical noise, and the cost of installing the antenna may increase. Furthermore, from the perspective of preventing global warming, ２ or O ２ When the above elements alone or a mixed gas containing a significant amount of these elements is used as the insulating gas, the conventional antennas cannot necessarily detect partial discharges with high accuracy.

[0019] Therefore, the diagnostic device for electric power gas insulated equipment and the diagnostic method for the insulation state of electric power gas insulated equipment, which will be described below, are adopted.

[0020] First Embodiment A diagnostic device for electric gas insulated equipment and a diagnostic method for electric gas insulated equipment according to a first embodiment will be described below with reference to the drawings.

[0021] Figure 2 shows a single-phase gas-insulated power transmission line as an example of electric power gas-insulated equipment, and a diagnostic device for electric power gas-insulated equipment. Figure 2 shows a single-phase gas-insulated power transmission line, which has the simplest configuration, as an example of electric power gas-insulated equipment. However, the basic structure described here can be applied to any electric power gas-insulated equipment, such as load break switches, disconnecting switches, grounding devices, gas-insulated switchgear (GIS), bus bars, gas-insulated power transmission lines, and gas-insulated transformers.

[0022] The gas-insulated power transmission pipeline shown in Figure 2 includes a sealed, hollow cylindrical sealed container 1 and a conductor 2 for carrying a high-voltage current. The conductor 2 is disposed inside the sealed container 1. The sealed container 1 is filled with an insulating gas 11. The sealed container 1 is made of metal or a solid insulator. The metal sealed container 1 is grounded. The solid insulator sealed container 1 is made of ceramics, resin, or the like. The gas-insulated power transmission pipeline shown in Figure 2 is structured so that the insulation of the conductor 2 is maintained by the insulating gas 11 filled inside the sealed container 1.

[0023] An insulating support spacer 7 is placed between the conductor 2 and the sealed container 1. The conductor 2 is positioned at the center of the sealed container 1 by the insulating support spacer 7. The insulating support spacers 7 are installed at a predetermined distance from each other along the longitudinal direction of the sealed container 1 and the conductor 2. The internal space of the sealed container 1 surrounded by two adjacent insulating support spacers 7 is defined as the measurement area 1a.

[0024] The insulating gas 11 is CO ２ , N ２ Or O ２ or CO ２ , N ２ Or O ２ The insulating gas 11 is a mixed gas containing any one of the following in a proportion of 5% or more in partial pressure. ２ Gas, CO ２ or N ２ One of the above and O ２ and O ２ A mixed gas containing fluorine atoms (F) and CO ２ A mixed gas containing fluorine atoms (F) and CO ２ and O ２ A mixed gas of the above is suitable.

[0025] CO ２ or N ２ One of the above and O ２ and O ２ The mixed gas in which the partial pressure of CO is 5% or more is, for example, ２ / O ２ Mixed gas, N ２ / O ２Examples of the mixed gas include O ２ is contained at a partial pressure of 5% or more.

[0026] Fluorine atom (F) containing gas and CO ２ The mixed gas is, for example, SF ６ / CO ２ Mixed gas, CF ４ / CO ２ Mixed gas, C ５ F １０ O / CO ２ Mixed gas, C ４ F ７ N / CO ２ Mixed gas, C ３ F ４ H ２ / CO ２ Any of the mixed gases may contain CO ２ is contained at a partial pressure of 5% or more.

[0027] Fluorine atom (F) containing gas and CO ２ and O ２ The mixed gas is, for example, SF ６ / CO ２ / O ２ Mixed gas, CF ４ / CO ２ / O ２ Mixed gas, C ５ F １０ O / CO ２ / O ２ Mixed gas, C ４ F ７ N / CO ２ / O ２ Mixed gas, C ３ F ４ H ２ / CO ２ / O ２ Any of the mixed gases may contain CO ２ and O ２ are contained in a total partial pressure of 5% or more.

[0028] The insulating gas 11 is CO ２ , N ２ Or O ２ or CO ２ , N ２ Or O ２By using a mixed gas containing any one of the following in a proportion such that the partial pressure is 5% or more, SF ６ In addition, the mixed gas containing fluorine atoms can reduce the impact on global warming compared to when CO is used as an insulating gas. ２ Or O ２ Since a higher insulating performance can be obtained compared to SF, by using this as the insulating gas 11, ６ It is possible to provide a compact and economical gas insulated electrical equipment that suppresses global warming compared to gas insulated electrical equipment that uses O as an insulating gas. Furthermore, when the above insulating gas is used, O ３ The generated O ３ is detected by a decomposed gas detection means as described later, thereby making it possible to detect the occurrence of partial discharge.

[0029] Next, the diagnostic device of this embodiment includes a decomposition gas detection means. The decomposition gas detection means detects O in the insulating gas 11 when the gas insulated equipment for electric power is in operation, i.e., when a high voltage is applied to the conductor 2. ３ The decomposition gas detection means shown in FIG. 2 includes an insulating gas sampling port 12 provided in the measurement region 1a of the sealed container 1, a sample gas bag 15 for storing the sample gas sampled from the insulating gas sampling port 12, and a gas analyzer for detecting O2 (ozone) in the sample gas. ３ and a gas detection tube 16 capable of detecting the concentration of insulating gas 11. A branch pipe 12a is connected to the measurement region 1a of the sealed container 1. An insulating gas sampling port 12 is provided at the tip of the branch pipe 12a. An open / close valve 13 is provided midway along the branch pipe 12a. The insulating gas sampling port 12 is normally kept sealed by the open / close valve 13. This prevents leakage of insulating gas 11 from the sealed container 1.

[0030] Only when checking whether partial discharge occurs in the measurement area 1a, the on-off valve 13 is opened to sample insulating gas from the insulating gas sampling port 12, and the insulating gas is stored in the sample gas bag 15. The O in the insulating gas is detected by the gas detector tube 16. ３ Confirm the existence of O ３The sample gas bag 15 is omitted, and the gas detector tube 16 is directly connected to the insulating gas sampling port 12 to measure the O concentration. ３ Confirm the existence of O ３ The concentration may be measured. The sample gas bag 15 and the gas detector tube 16 do not need to be attached all the time, but may be attached as needed.

[0031] The insulating gas sampling port 12 is preferably installed below the middle position in the height direction of the measurement area 1a, that is, below the direction in which gravity acts.

[0032] When a plurality of measurement regions 1a are provided in the sealed container 1 by the insulating support spacer 7, the decomposed gas detection means may be provided in each of the measurement regions 1a.

[0033] The gas detection tube 16 is detachable from the insulating gas sampling port 12 or the sample gas bag 15. ３ The presence of O ３ It is advisable to use a detector tube that can measure the concentration. ３ It is preferable to use a gas detector having a higher detection sensitivity for CO than for CO or HF. A gas sensor may be used instead of the gas detection tube 16. The gas sensor may be detachable from the insulating gas sampling port 12, or may be permanently connected to the insulating gas sampling port 12.

[0034] 2, the diagnostic device of this embodiment may be provided with an adsorbent 14. The adsorbent 14 is placed in a measurement region 1a of the sealed container 1 in which the decomposed gas detection means is placed. The adsorbent 14 is placed inside the sealed container 1. The adsorbent 14 adsorbs one or more of CO, HF, and nitrogen oxides.

[0035] Next, the diagnostic method of this embodiment will be described. ２ Or O ２ When a partial discharge 5 occurs in an insulating gas 11 containing, for example, a minute foreign particle 4, the gas is decomposed and atomized by the discharge, and in the process of atomic recombination, O is released as a decomposition gas. ３It was found that O and CO are generated. When an insulator made of fluororesin is present near the discharge, ３ It has been found that HF ​​can also be generated in addition to CO. Figure 2 shows how decomposition gas G is generated by the occurrence of partial discharge 5.

[0036] In the diagnostic method of this embodiment, in order to detect the occurrence of partial discharge, O is detected in the insulating gas 11 by the decomposition gas detection means. ３ Check whether the insulating gas 11 contains O. ３ If the detected gas includes a partial discharge, it can be determined that a partial discharge has occurred within the measurement area 1a where the decomposed gas detection means is installed. This makes it possible to quickly detect the occurrence of an abnormality in gas-insulated electrical equipment, for example, a single-phase gas-insulated power transmission pipeline. Furthermore, it is possible to quickly identify the location of a partial discharge in the gas-insulated power transmission pipeline.

[0037] Specifically, the insulating gas is sampled from the insulating gas sampling port 12 and introduced into the gas detection tube 16, thereby detecting O in the insulating gas. ３ If a gas sensor is attached to the insulating gas sampling port 12, the gas sensor checks whether the insulating gas contains O. ３ Check if it contains

[0038] As mentioned above, when partial discharge 5 occurs, CO or HF may also be included in the gas to be analyzed. ２ When it contains NO, NO as decomposition gases ２ , N ２ O ４ In this case, the gas detector tube 16 or the gas sensor of the decomposition gas detection means detects O ３ Not only that, if CO, HF or nitrogen oxides are detected, ３ Therefore, the detection error of the gas detector tube 16 or the gas sensor provided in the decomposition gas detection means becomes large. ３It is preferable to select a gas having a higher detection sensitivity for O than for CO, HF, or nitrogen oxides. ３ This can reduce false positives.

[0039] For the same purpose, an adsorbent 14 for adsorbing CO, HF, or nitrogen oxides, or one or more of these, may be installed in the measurement area 1a. ３ This is effective in suppressing false positives of occurrences.

[0040] The insulating gas 11 contains N ２ In this case, it is possible to evaluate whether or not partial discharge occurs by appropriately measuring the concentration of nitrogen oxides (NxOy) generated.

[0041] In addition, O generated as a decomposition gas ３ has a higher density than other decomposition gases such as CO, HF, and nitrogen oxides. ３ Therefore, by installing the decomposition gas detection means below the measurement area 1a, it is possible to obtain a more sensitive O ３ It becomes possible to detect.

[0042] The above configuration makes it possible to provide highly reliable gas-insulated electrical equipment that can prevent global warming and detect insulation defects with high accuracy and low cost. Furthermore, if a single piece of gas-insulated electrical equipment has multiple measurement areas 1a, it is possible to identify the measurement area 1a where an abnormal discharge has occurred or is currently occurring.

[0043] Second Embodiment A diagnostic device for gas insulated electrical equipment and a diagnostic method for the insulation state of gas insulated electrical equipment according to a second embodiment will be described below with reference to the drawings.

[0044] FIG. 3 shows a gas-insulated switchgear (GIS) as an example of gas-insulated electrical equipment, and a diagnostic device for gas-insulated electrical equipment.

[0045] The gas-insulated switchgear shown in Figure 3 includes a sealed, hollow sealed container 1, a conductor 2 for passing a high-voltage current, a first contact 31A and a second contact 31B that can be opened and closed, a drive device 33 that moves the second contact 31B back and forth relative to the first contact 31A, an insulated drive rod 32 that connects the second contact 31B to the drive device 33, a connection conductor 31C that electrically connects the conductor 2 to the first contact 31A, a connection conductor 31D that electrically connects the conductor 2 to the second contact 31B, support insulators 30A and 30B that fix the connection conductors 31C and 31D within the sealed container 1, and an insulating support spacer 7 that positions the conductor 2 inside the sealed container 1.

[0046] The components arranged inside the sealed container 1 are the conductor 2, the first contact 31A, the second contact 31B, the insulating drive rod 32, the connecting conductors 31C and 31D, the support insulators 30A and 30B, and the insulating support spacer 7. The component arranged outside the sealed container 1 is the drive unit 33. The sealed container 1 is filled with an insulating gas 11.

[0047] The sealed container 1 is composed of a main body 1A and two conductor storage sections 1B protruding from the main body 1A. The main body 1A and the conductor storage sections 1B are connected to each other. The main body 1A stores a first contact 31A, a second contact 31B, an insulated drive rod 32, connecting conductors 31C and 31D, and supporting insulators 30A and 30B.

[0048] The first contact 31A is fixed inside the sealed container 1 by a supporting insulator 30A and a connecting conductor 31C. The second contact 31B is movable toward and away from the first contact 31A by an insulated drive rod 32 and a drive device 33. That is, the drive device 33 can move the second contact 31B toward and into contact with the first contact 31A via the insulated drive rod 32, or move the second contact 31B away from the first contact 31A. In FIG. 3 , the left side of the dashed-dotted line L shows a state in which the second contact 31B and the first contact 31A are in contact. The right side of the dashed-dotted line L shows a state in which the second contact 31B and the first contact 31A are separated, generating an arc discharge 34.

[0049] The insulated drive rod 32 is inserted into a through-hole (not shown) provided in the connection conductor 31D, and a second contact 31B is attached to the tip of the insulated drive rod 32. The connection conductor 31D and the second contact 31B are always in a conductive state. The drive device 33 moves the insulated drive rod 32 toward or away from the first contact 31A, thereby opening and closing the second contact 31B relative to the first contact 31A. When the second contact 31B, which was in contact with the first contact 31A, moves away from the first contact 31A, an arc discharge 34 occurs between the second contact 31B and the first contact 31A. The generated arc is extinguished in the insulating gas 11, thereby interrupting the current.

[0050] The main body 1A of the sealed container 1 may be provided with an adsorbent 14. The adsorbent 14 is placed in the measurement region 1a of the sealed container 1. The adsorbent 14 is placed inside the sealed container 1. The adsorbent 14 adsorbs one or more of CO, HF, and nitrogen oxides.

[0051] The two conductor storage sections 1B store a conductor 2 and an insulating support spacer 7. A portion of the conductor 2 is located in the main body section 1A. In each of the two conductor storage sections 1B, an insulating support spacer 7 is located between the conductor 2 and the sealed container 1. The internal space of the sealed container 1 separated by the two insulating support spacers 7 is defined as a measurement area 1a.

[0052] The sealed container 1 is made of metal or a solid insulator. The metal sealed container 1 is grounded. The solid sealed container 1 is made of ceramics, resin, or the like. The gas-insulated switchgear shown in Fig. 3 has a structure in which the insulation of the conductor 2, first contact 31A, second contact 31B, and connecting conductors 31C and 31D is maintained by the insulating gas 11 filled in the sealed container 1, the insulating drive rod 32, and the insulating support spacer 7.

[0053] The insulating gas 11 is CO ２ , N ２ Or O ２ or CO ２ , N ２ Or O ２A mixed gas containing any one of the above in a proportion such that the partial pressure is 5% or more is used. The details of the insulating gas 11 are as explained in the first embodiment. When this insulating gas 11 is used, O ３ The generated O ３ is detected by a decomposed gas detection means as described later, thereby making it possible to detect the occurrence of partial discharge.

[0054] Next, the diagnostic device of this embodiment includes a decomposition gas detection means. ３ The decomposition gas detection means shown in FIG. 3 includes an insulating gas sampling port 12 provided in the measurement region 1a of the main body 1A of the sealed container 1, a sample gas bag 15 for storing the sample gas sampled through the insulating gas sampling port 12, and a gas analyzer for detecting O2 (ozone) in the sample gas. ３ and a gas detection tube 16 capable of detecting the concentration of the decomposed gas. The decomposed gas detection means of this embodiment is the same as the decomposed gas detection means of the first embodiment.

[0055] The diagnostic device of this embodiment also includes a current switching monitoring means 35, a calculation means 37 that calculates the ozone decay time T using the following formula (1), and a control means 38. The diagnostic device may also include an alarm means 23.

[0056] The current switching monitoring means 35 is connected to the drive device 33, and has the function of recording the time when the current is switched on or off by the operation of the first contact 31A and the second contact 31B described above, and transmitting the result to the calculation means 37.

[0057] The calculation means 37 has a function of calculating the ozone decay time T by the following formula (1): In addition, the calculation means 37 is connected to a current measurement means 36 that measures the current value in the conductor 2.

[0058] T=(-1.2)×D×{(V / 509)×(100 / X)×(40 / I) １．５} + 40 ... (1)

[0059] In the formula (1), T is the ozone decay time (Hr), V is the spatial volume (L) in the measurement region 1a of the sealed container 1, and X is the CO２ and O ２ where I is the arc current (kA) when the current is switched, and D is the lower limit of ozone detection (ppm) of the decomposition gas detection means. The arc current I (kA) when the current is switched can be determined from the current value of the conductor 2 measured by the current measurement means 36.

[0060] Note that Equation 1 is defined as a linear approximation based on actual measurement data. If T is a negative value, the detection sensitivity of the decomposition gas detection means is insufficient for the target V, X, and I conditions, i.e., O ３ This means that the lower detection limit D is too large. In this case, it is necessary to prepare a decomposition gas detection means with higher detection sensitivity.

[0061] The control means 38 compares the time elapsed from the time of current switching recorded by the current switching monitoring means 35 with the ozone decay time T calculated by the calculation means 37, and if the elapsed time is longer than the ozone decay time T, detects O2 in the insulating gas by the decomposition gas detection means. ３ Detect whether it contains

[0062] The warning means 23 has a function of issuing a warning to notify an operator when the control means 38 determines that a partial discharge is occurring.

[0063] Next, the diagnostic method of this embodiment will be described. As described in the first embodiment, ２ Or O ２ When an abnormal discharge occurs in the insulating gas 11 containing O, the gas is decomposed and atomized by the discharge, and O is released as decomposition gas in the process of atomic recombination. ３ If an insulator made of fluororesin is present near the discharge, O ３ In addition to CO and CO, HF may also be generated. Arc discharge 34 may also occur when the first contact 31A and the second contact 31B are deactivated. ３ and CO are generated, and HF may also be generated.

[0064] Therefore, in the diagnostic method of this embodiment, in the same way as in the first embodiment, in order to detect the occurrence of partial discharge, O is detected in the insulating gas 11 by the decomposition gas detection means.３ Check whether the insulating gas 11 contains O. ３ If the detected gas is included, it can be evaluated that some kind of discharge is occurring in the vicinity of the measurement region 1a where the decomposed gas detection means is installed.

[0065] However, when the gas insulated electrical equipment is a switchgear as in this embodiment, ３ Decomposition gases of insulating gas, including O, are generated not only during abnormal discharge but also during intended normal current switching. That is, the insulating gas is decomposed and decomposition gases are generated by arc discharge 34 that occurs during current switching. For this reason, it is necessary to prevent O from being contained in the insulating gas. ３ When decomposition gas such as the above is detected, it is not easy to determine whether the decomposition gas is due to an abnormal discharge or due to the arc discharge 34 that occurs during normal current switching.

[0066] Therefore, we investigated the issue and found that even if discharge occurs once in the sealed container 1, O ３ The concentration was found to decrease. ３ 1 is a graph showing the change in concentration over time with respect to the initial generation amounts of CO, HF, and O. ３ is a highly active molecule and will naturally decompose over time. ３ The ozone decay time T (hours) until the concentration falls below the detection limit of a decomposition gas detection means such as a gas detection tube or gas sensor is determined by the spatial volume V (L) in the measurement region 1a of the sealed container 1 and the CO ２ and O ２ The total content X (volume %) of ３ It depends on the lower detection limit D (ppm) of ozone. Formulated based on experiments and theory, it is as shown in the above formula 1. Formula 1 makes it possible to estimate the ozone decay time T under any conditions. When O is present in the insulating gas after the ozone decay time T (hours) has elapsed, ３ If detected, then O ３ can be considered to have been caused by an abnormal discharge.

[0067] In the diagnostic method of this embodiment, a diagnostic device is provided with a current switching monitoring means 35, a calculation means 37 that calculates an ozone decay time T by the following formula (1), a control means 38, and a decomposition gas detection means. The current switching monitoring means 35 records the time when the current is switched. The calculation means 37 calculates the ozone decay time T. The control means 38 compares the elapsed time from the time when the current is switched with the ozone decay time T, and when the elapsed time becomes longer than the ozone decay time T, the decomposition gas detection means detects O2 in the insulating gas. ３ Check whether it is included. ３ If this is detected, it is determined that an abnormal discharge is occurring. ３ The detection of the abnormal discharge indicates that an abnormal discharge is actually occurring continuously. If it is determined that an abnormal discharge is occurring, an alarm may be issued by the alarm means 23.

[0068] Figure 5 shows the time course of decomposition gas generated by current interruption. In Figure 5, a 5 kA current was interrupted after 10 hours, and a 8 kA current was interrupted after 60 hours. O was generated as decomposition gas by each current interruption. ３ As shown in Figure 5, when we focus on CO, it does not decay over time, or the decay time is extremely long. Therefore, it is not suitable as a gas for detecting partial discharge. Also, HF, one of the decomposition gases, is generated only when an insulator made of fluororesin is present near the discharge, so it is not necessarily generated. ３ The O concentration becomes below the detection limit after the ozone decay time T has elapsed since the current was cut off. ３ If O is detected, it is due to a factor other than current interruption, i.e., an abnormal discharge. ３ Therefore, O is the gas to be monitored to detect abnormal discharge. ３ is optimal.

[0069] In summary, when a time longer than the ozone decay time T has elapsed since the intended normal current switching, O ３If this is detected, it can be known that an abnormal discharge is actually continuing in the target measurement area 1a.

[0070] The above configuration makes it possible to provide highly reliable gas-insulated electrical equipment that can prevent global warming and detect insulation defects with high accuracy and low cost. Furthermore, if a single piece of gas-insulated electrical equipment has multiple measurement areas 1a, it is possible to identify the measurement area 1a where an abnormal discharge has occurred or is currently occurring.

[0071] (Third embodiment) Next, a third embodiment will be described with reference to Fig. 6. The basic configuration is the same as that shown in Fig. 2. However, there are differences in the following points. In Fig. 6, O ３ The gas sensor 21 is attached to the sealed container 1. The gas sensor 21 detects O in the insulating gas 11 inside the sealed container 1. ３ The gas sensor 21 can be based on various principles, such as a principle that utilizes changes in thermal conduction, a principle that utilizes changes in capacitance due to electric polarization, a principle that utilizes changes in resistance of a semiconductor element, a principle that utilizes absorption of a specific wavelength of light, or a combination of these. The gas sensor 21 constantly measures the O concentration in the insulating gas in the sealed container 1. ３ Detects and O ３ Outputs information about the detection.

[0072] The information output from the gas sensor 21 is sent as an output signal to the information transmission means 22. The information transmission means 22 is installed in a remote location away from the target gas-insulated equipment for electric power. ３ The information transmitting means 22 is composed of an amplifier, a noise eliminator, a signal output device, a transmission cable, and the like.

[0073] The alarm means 23 detects that the gas sensor 21 detects O2 even though the elapsed time from the normal current switching operation exceeds the ozone decay time T. ３ If any abnormality is detected, an alarm will be issued to the facility manager of the gas-insulated equipment.

[0074] If the gas-insulated equipment for electric power is, for example, a gas circuit breaker, during current interruption operation, a specific location within the sealed container 1 is exposed to high local pressure and high temperature due to mechanical vibration or high-temperature gas flow generated by arc discharge. When the gas sensor 21 is to be disposed in this location, it is advisable to provide a protective cover 24 as appropriate.

[0075] This embodiment provides the following unique advantages. Specifically, the diagnostic device, which includes the gas sensor 21, the information transmission means 22, and the alarm means 23, can remotely determine whether or not an abnormal discharge has occurred in the gas-insulated equipment, without requiring an operator to visit the installation site of the gas-insulated equipment. This reduces the maintenance costs for the gas-insulated equipment. Furthermore, by providing a protective cover 24 on the gas sensor 21, the gas sensor 21 can be protected from mechanical vibrations specific to gas circuit breakers or from high pressures and high temperatures caused by high-temperature gas flows generated by arc discharge.

[0076] The above configuration makes it possible to provide highly reliable gas insulated electrical equipment that can prevent global warming, detect insulation defects with high accuracy and low cost, and reduce maintenance costs for the gas insulated equipment.

[0077] According to at least one of the embodiments described above, by providing the decomposed gas detection means, it is possible to detect the occurrence of partial discharge inside the device due to poor insulation and to diagnose the functional maintenance state.

[0078] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0079] 1...sealed container, 2...conductor, 11...insulating gas, 4...microscopic foreign matter, 5...partial discharge, 6...dielectric breakdown discharge, 7...insulating support spacer, 12...insulating gas sampling port, 13...opening / closing valve, 14...adsorbent, 21...gas sensor, 22...information transmission means, 23...alarm means, 24...protective cover

Claims

1. A sealed container divided into a plurality of measurement regions, a conductor disposed inside the sealed container, and CO filled inside the sealed container to insulate the conductor. ２ Or O ２ and an insulating gas containing O ３ A diagnostic device for gas-insulated electrical equipment, comprising a decomposition gas detection means for detecting whether or not the equipment contains a decomposition gas.

2. A sealed container divided into a plurality of measurement regions, a conductor disposed inside the sealed container, and CO filled inside the sealed container to insulate the conductor. ２ Or N ２ and an insulating gas containing the above-mentioned, wherein the measurement area of ​​the sealed container is provided with a decomposition gas detection means for detecting whether the insulating gas contains CO or nitrogen oxides.

3. The insulating gas is CO ２ , N ２ Or O ２ or CO ２ , N ２ Or O ２ 3. The diagnostic device for gas insulated electrical equipment according to claim 1, wherein the gas mixture contains any one of the above in a proportion such that the partial pressure of the gas mixture is 5% or more.

4. The insulating gas is CO ２ Gas, CO ２ Or N ２ Either one of the above and O ２ Including and O ２ A mixed gas having a partial pressure of 5% or more, SF ６ , C.F. ４ , C ５ F １０ O.C. ４ F ７ N or C ３ F ４ H ２ Either one of the above and CO ２ and CO ２ A mixed gas having a partial pressure of 5% or more, SF ６ and CO ２ and O ２ and CO ２ and O ２ A mixed gas in which the total of CF is 5% or more in partial pressure. ４ and CO ２ and O ２ and CO ２ and O ２ A mixed gas having a partial pressure of 5% or more in total, ５ F １０ O and CO ２ and O ２ and CO ２ and O ２ A mixed gas having a partial pressure ratio of 5% or more in total, ４ F ７ NCO ２ and O ２ and CO ２ and O ２ A mixed gas in which the total of the partial pressures is 5% or more, or ３ F ４ H ２ CO ２ and O ２ and CO ２ and O ２ 3. The diagnostic device for gas insulated electrical equipment according to claim 1, wherein the gas is a mixed gas having a partial pressure ratio of 5% or more in total of the gases.

5. A current switching monitoring means for recording the time when the current is switched on and off, and a calculation means for calculating an ozone decay time T by the following formula (1), and a means for comparing the elapsed time from the time when the current is switched on and off recorded by the current switching monitoring means with the ozone decay time T calculated by the calculation means, and when the elapsed time becomes longer than the ozone decay time T, detecting ozone by the decomposition gas detection means. ３ and a control unit for detecting whether the gas insulated equipment for electric power is included. １．５ }+40 ... (1) where, in formula (1), T is the ozone decay time (Hr), V is the spatial volume (L) of the measurement region of the sealed container, and X is the amount of CO ２ and O ２ I is the arc current (kA) when the current is switched, and D is the lower detection limit (ppm) of the decomposition gas detection means.

6. The decomposition gas detection means detects O in the insulating gas. ３ 6. The diagnostic device for electric power gas insulated equipment according to claim 5, further comprising: a sensor information transmission means for transmitting information when a fault is detected; and an alarm means for issuing an alarm based on the information received from the sensor information transmission means.

7. The decomposition gas detection means comprises an insulating gas sampling port provided in the measurement region of the sealed container, and O in the sample gas sampled from the insulating gas sampling port. ３ and a gas detector capable of detecting a concentration of 8. A diagnostic device for electric power gas insulated equipment as described in claim 2, wherein the decomposition gas detection means comprises: an insulating gas sampling port provided in the measurement area of ​​the sealed container; and a gas detection tube capable of detecting the concentration of CO or nitrogen oxides in the sample gas sampled from the insulating gas sampling port.

9. The decomposition gas detection means detects O in the insulating gas. ３ 2. The diagnostic device for gas-insulated electrical power equipment according to claim 1, wherein the gas sensor is a gas sensor for detecting 10. A diagnostic device for electric power gas-insulated equipment according to claim 2, wherein the decomposed gas detection means is a gas sensor for detecting CO or nitrogen oxides in the insulating gas.

11. The decomposition gas detection means is O ３ 2. The diagnostic device for electric power gas-insulated equipment according to claim 1, wherein the detection sensitivity for said gas-insulated equipment is higher than the detection sensitivity for CO, HF or nitrogen oxides.

12. A diagnostic device for electric power gas insulated equipment as described in claim 1 or claim 2, wherein an adsorbent material for adsorbing one or more of CO, HF, and nitrogen oxides is installed in the measurement area of ​​the sealed container in which the decomposition gas detection means is installed.

13. A diagnostic device for electric power gas insulated equipment as described in claim 1 or 2, wherein the decomposition gas detection means is installed below the midpoint in the height direction of the measurement area of ​​the sealed container.

14. A sealed container divided into a plurality of measurement regions, a conductor disposed inside the sealed container, and CO filled inside the sealed container to insulate the conductor. ２ Or O ２ and an insulating gas containing O, the method comprising: comparing an elapsed time from a current switching time with an ozone decay time T calculated by the following formula (2), and determining that O is present in the insulating gas if the elapsed time is longer than the ozone decay time T. ３ Check if it is included and ３ A diagnostic method for gas-insulated electric power equipment, which determines that partial discharge is occurring when a voltage T is detected. T = (-1.2) x D x {(V / 509) x (100 / X) x (40 / I)} １．５ }+40 ... (2) where, in formula (1), T is the ozone decay time (Hr), V is the spatial volume (L) of the measurement region of the sealed container, and X is the amount of CO ２ and O ２ is the total content (volume %) of the ozone gas, I is the arc current (kA) when the current is switched, and D is the lower detection limit of ozone (ppm).

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