JP7399326B2 - Diagnostic device and method for gas insulated equipment, and gas insulated equipment using this diagnostic method - Google Patents

Description

The present disclosure relates to gas insulated equipment.

In gas insulated equipment such as gas insulated switchgear, insulation performance is ensured by storing the conductor to which high voltage is applied in a metal grounded tank and filling the airtight space inside the grounded tank with insulating gas. ing.
Conventionally, SF6, for example, has been widely used as an insulating gas for such gas-insulated equipment. However, although SF6 has high insulation performance, it has a large global warming potential (GWP), which indicates the effect on global warming. Therefore, from the viewpoint of reducing environmental load, insulating gases that can replace SF6 are being considered. Among these, organic fluorine compound gases containing fluorine (F) and carbon (C) such as hydrofluoroolefin gas and fluoroketone gas, which have a low global warming potential and are environmentally friendly and have good insulation performance. has been proposed as a candidate for an alternative insulating gas.

Generally, it is effective and economical to improve insulation performance by mixing a gas with a low environmental load, such as air, with the organic fluorine compound gas.
Patent Document 1 discloses a technique regarding an insulating gas mixed with fluoroketone gas and air. Furthermore, Patent Document 2 discloses an insulating gas that is a mixture of hydrofluoroolefin gas and air. A gas mixed with an organic fluorine compound and air is used as an insulating gas in gas-insulated equipment.

On the other hand, due to internal discharge caused by the operation of the gas insulated equipment, organic fluorine compounds in the mixed insulating gas are decomposed or oxidized, and generated gas such as decomposed gas is generated. The gas concentration of organic fluorine compounds in the insulating gas of gas-insulated equipment is a condition for ensuring the necessary insulation performance. When the organic fluorine compound is consumed by decomposition or oxidation, the insulation performance of gas-insulated equipment will deteriorate. For convenience, this state will be referred to as deterioration of the insulating gas. In order to evaluate the insulation performance of gas-insulated equipment, it is essential to evaluate the gas concentration of organic fluorine compounds in the insulating gas and diagnose the degree of deterioration of the insulating gas.

It is possible to accurately measure the gas concentration of organic fluorine compounds using a special analyzer such as GC/MS. However, it requires specialized analytical skills to sample the insulating gas from gas-insulated equipment and diagnose the deterioration by measuring the gas concentration of organic fluorine compounds in the insulating gas using an analyzer such as GC/MS. However, it is inefficient and unsuitable for on-site work.
For this reason, in Patent Document 3, by providing an insulating gas concentration monitoring section and a decomposed gas concentration monitoring section in the gas insulated equipment, the concentration of the alternative gas in the mixed gas generated by internal discharge and the decomposed gas of this alternative gas is detected. Then, it is determined whether insulation performance has deteriorated depending on the degree of deterioration of the mixed gas. As methods for detecting gas concentration, detection using laser irradiation, thermal conductivity change, or infrared irradiation is described.

However, when detecting gas concentration using laser irradiation or infrared irradiation, signals from decomposed gases of organic fluorine compounds and decomposed gases with similar compositions interfere with each other, impairing the accuracy of gas concentration measurement. It is difficult to increase.
Also, the thermal conductivity of a gas depends mainly on the average molecular weight of the gas. The average molecular weight decreases due to decomposition or oxidation of the organic fluorine compound. However, highly reactive decomposed gases such as HF are gradually adsorbed to adsorbents installed in gas-insulated equipment. Therefore, even if the gas concentration of the organic fluorine compound in the insulating gas is constant, the thermal conductivity changes as the amount of gas with a small molecular weight, such as HF, decreases. Therefore, accurate measurement of organic fluorine compounds by thermal conductivity is difficult.

Further, Patent Document 4 discloses a technique for detecting generated decomposed gas with a detection tube regarding deterioration diagnosis of insulating gas. However, the inventor of the present disclosure has discovered that hydrogen fluoride (HF), which is the main cracked gas decomposed from an insulating gas mixed with hydrofluoroolefin gas and air, can be detected using a detection tube (No. Detection was attempted using hydrogen fluoride (No. 17LL Gastech detector tube), but the signals from hydrofluoroolefin gas and cracked gas containing fluorine other than HF interfered, making it impossible to measure the HF gas concentration. It was confirmed. It is also difficult to diagnose the deterioration of an insulating gas mixed with an organic fluorine compound by detecting decomposed gas.

In the case of an insulating gas that is a mixture of an organic fluorine compound and air, the type of gas that is absorbed by reacting with the decomposed gas from the organic fluorine compound and the moisture adsorbent of gas insulated equipment, etc., compared to the conventional single type of gas. Due to this interference, it is difficult to quantify the gas concentration of the organic fluorine compound in the insulating gas or the concentration of the decomposed gas. This makes it possible to accurately evaluate the degree of deterioration of the insulating gas used in gas insulated equipment, which is affected by the degree of deterioration of the insulating gas, in gas insulated equipment that uses a gas mixture of organic fluorine compounds and air as the insulating gas. I can't.

Special table 2014-506376 publication Patent No. 6656496 JP2007-273282A Japanese Patent Application Publication No. 2019-47602

The present disclosure has been made to solve the above-mentioned problems, and provides a diagnostic method and a diagnostic device for gas insulated equipment that can improve the accuracy of evaluating the degree of deterioration of an insulating gas used in gas insulated equipment. The purpose of the present invention is to provide gas-insulated equipment that uses this diagnostic method and has less environmental impact.

A diagnostic device for gas insulated equipment according to the present disclosure is a diagnostic device for gas insulated equipment that has a grounded tank filled with a mixture of an organic fluorine compound and a gas containing oxygen as an insulating gas, and in which samples are collected from the grounded tank. The oxygen concentration measuring unit measures the oxygen concentration in the insulating gas, and compares the oxygen concentration with a pre-input oxygen concentration threshold, and if the oxygen concentration is equal to or higher than the oxygen concentration threshold, the degree of deterioration of the insulating gas is determined A diagnostic unit is provided that determines that the performance can be ensured, and when the oxygen concentration is lower than the oxygen concentration threshold, determines that the degree of deterioration of the insulating gas is such that the required insulation performance cannot be ensured.
A diagnostic method for a gas insulated device according to the present disclosure is a method for diagnosing a gas insulated device having a grounded tank filled with a mixture of an organic fluorine compound and a gas containing oxygen as an insulating gas. A gas sampling step for sampling gas, an oxygen concentration measurement step for measuring the oxygen concentration in the insulating gas, and comparing the oxygen concentration with a pre-input oxygen concentration threshold, and if the oxygen concentration is equal to or higher than the oxygen concentration threshold, the insulating gas is and a diagnostic step of determining that the degree of deterioration of the insulating gas is such that the required insulation performance can be secured, and when the oxygen concentration is lower than the oxygen concentration threshold, determining that the degree of deterioration of the insulating gas is such that the required insulation performance cannot be secured.
The gas insulated equipment according to the present disclosure includes a grounded tank filled with a gas mixture of an organic fluorine compound and a gas containing oxygen as an insulating gas, and includes a gas sampling step of collecting the insulating gas from the grounded tank, and a gas sampling step of collecting the insulating gas from the grounded tank. The oxygen concentration measurement step compares the oxygen concentration with a pre-input oxygen concentration threshold, and if the oxygen concentration is greater than or equal to the oxygen concentration threshold, the degree of deterioration of the insulating gas ensures the required insulation performance. If the oxygen concentration is lower than the oxygen concentration threshold, the diagnosis method for gas insulated equipment is used to diagnose the insulating gas. Diagnose whether the degree of deterioration is such that the required insulation performance can be secured.

According to the diagnostic method and diagnostic device for gas insulated equipment according to the present disclosure, in order to evaluate the degree of deterioration of the insulating gas sealed in the gas insulated equipment by measuring the oxygen concentration in the insulating gas sealed in the gas insulated equipment, Compared to the conventional technology, it is possible to avoid the inability to accurately measure the gas concentration of the organic fluorine compound due to signal interference from the decomposed gas, and it is possible to improve the accuracy of evaluating the degree of deterioration of the insulating gas.
According to the gas insulated equipment using the diagnostic method according to the present disclosure, an insulating gas that is a mixture of an organic fluorine compound, which is advantageous in terms of global warming countermeasures, and a gas containing oxygen, such as air, is used, and the insulation sealed in the gas insulated equipment is used. In order to evaluate the degree of deterioration of the insulating gas sealed in gas insulated equipment by measuring the oxygen concentration in the gas, the gas concentration of organic fluorine compounds can be accurately measured using signal interference from decomposed gas compared to conventional technology. This makes it possible to avoid failures and improve the accuracy of evaluating the degree of deterioration of the insulating gas.

FIG. 3 is a diagram showing the correlation between the amount of decrease in HFO-1234yf gas due to discharge in the gas insulated device according to the present disclosure and the oxygen concentration. FIG. 2 is a conceptual diagram showing the relationship between oxygen concentration in an insulating gas and withstand voltage through a discharge test in a gas insulated device according to the present disclosure. FIG. 1 is a configuration diagram of a gas insulated device according to Embodiment 1 of the present disclosure. FIG. 2 is a diagram showing a flow of a diagnostic process for implementing a diagnostic method for diagnosing the degree of deterioration of an insulating gas in a gas insulated device according to Embodiment 1 of the present disclosure. FIG. 2 is a configuration diagram of a gas insulated device according to Embodiment 2 of the present disclosure. FIG. 7 is an image diagram of the connection between the oxygen concentration measuring section and the gas sampling section that are removed from the gas insulated device according to Embodiment 2 of the present disclosure. FIG. 7 is a diagram showing a flow of a diagnostic process for implementing a diagnostic method for diagnosing the degree of deterioration of an insulating gas in a gas insulated device according to a second embodiment of the present disclosure.

In gas insulated equipment that uses a gas mixture of an organic fluorine compound and a gas containing oxygen as the insulating gas, as the gas insulated equipment is used, the organic fluorine compound in the insulating gas decomposes or oxidizes due to electrical discharge, causing the insulating gas to deteriorate. Deterioration progresses and insulation performance decreases. Organofluorine compounds are mainly consumed through chemical reactions with oxygen. The amount of decrease in consumed organic fluorine compound gas correlates with the amount of decrease in oxygen, and the amount of decrease in organic fluorine compound gas in the insulating gas correlates with oxygen concentration.
The amount of reduction in organic fluorine compound gas directly affects insulation performance. The insulation performance of an insulating gas in gas-insulated equipment can be measured, for example, by evaluating the voltage that causes dielectric breakdown in the gas, and can be quantified as a withstand voltage. It can be evaluated that the higher the withstand voltage value, the higher the insulation performance. The measurement of withstand voltage is carried out using, for example, a test system that simulates an actual machine.

Using the embodiment, the oxygen concentration in the insulating gas is measured to diagnose the degree of deterioration of the insulating gas sealed in gas-insulated equipment.Before explaining, the amount of decrease in the organic fluorine compound gas in the mixed insulating gas is What can be evaluated by the oxygen concentration in the insulating gas will be explained.
The following describes the amount of decrease in organic fluorine compound gas in the insulating gas and the oxygen It will be explained that the amount of decrease in organic fluorine compound gas due to discharge can be evaluated based on the oxygen concentration.

Hydrofluoroolefin gas is expressed as HFO. When a discharge test is performed in an atmosphere of an insulating gas containing a mixture of HFO and air, decomposition or oxidation of HFO occurs. The decomposition or oxidation of HFO mainly involves a chemical reaction between HFO and O ₂ (oxygen) in the air, and the main gases produced are HF (hydrogen fluoride), CO ₂ (carbon dioxide), and CF ₄ (carbon tetrafluoride). is generated. HF gas and CF ₄ gas in the generated gas are also called HFO decomposition gas.
The chemical reaction formula in this case is shown in formula (1).

式（１）において、化学反応式の係数であるａ、ｂ、ｃ、ｄはＨＦＯの種類によって値が決定される。
放電により消費されたＨＦＯの減少量、Ｏ_２の減少量はそれぞれΔＨＦＯ、ΔＯで表示する。ΔＨＦＯは次の式（２）で表記し、ΔＯは次の式（３）で表記する。

In equation (1), the values of a, b, c, and d, which are coefficients of the chemical reaction equation, are determined depending on the type of HFO.
The amount of decrease in HFO and the amount of decrease in O ₂ consumed by discharge are expressed as ΔHFO and ΔO, respectively. ΔHFO is expressed by the following equation (2), and ΔO is expressed by the following equation (3).

式（２）において、ＨＦＯ_ｏは初期状態における絶縁ガス中のＨＦＯのガス量であり、ＨＦＯ_ｉは放電後の絶縁ガス中のＨＦＯのガス量である。
式（３）において、Ｏ_ｏは初期状態における絶縁ガス中のＯ_２のガス量であり、Ｏ_ｉは放電後の絶縁ガス中のＯ_２のガス量である。
ここで、ＨＦＯ、Ｏ_２のガス量とは、ＨＦＯ、Ｏ_２の単位体積当たりの分子の数である。ＨＦＯ、Ｏ_２の減少量とは、放電前後の分子の数の差である。ガス量とガスの減少量との単位はｍｏｌである。
式（２）と式（３）において、初期状態のガス量から放電後のガス量を引くのは、ΔＨＦＯ、ΔＯを全て正の値にするためである。
式（１）により、ΔＨＦＯとΔＯとの関係を次の式（４）のように表記する。

In equation (2), HFO _o is the amount of HFO in the insulating gas in the initial state, and HFO _i is the amount of HFO in the insulating gas after discharge.
In equation (3), O _o is the amount of O ₂ in the insulating gas in the initial state, and O _i is the amount of O ₂ in the insulating gas after discharge.
Here, the gas amount of HFO and O ₂ is the number of molecules per unit volume of HFO and O ₂ . The amount of decrease in HFO and O ₂ is the difference in the number of molecules before and after discharge. The units of the gas amount and the gas reduction amount are mol.
In equations (2) and (3), the reason for subtracting the gas amount after discharge from the gas amount in the initial state is to make ΔHFO and ΔO all positive values.
Based on the equation (1), the relationship between ΔHFO and ΔO is expressed as the following equation (4).

生成されたＨＦ、ＣＯ_２、ＣＦ_４のガス量をそれぞれＨＦ、ＣＯ_２、ＣＦ_４で示す。式（１）により、生成されたＨＦ、ＣＯ_２、ＣＦ_４のガス量とΔＯとの関係を次の式（５）、式（６）、式（７）のように表記する。

The gas amounts of generated HF, CO ₂ and CF ₄ are indicated by HF, CO ₂ and CF ₄ , respectively. Based on equation (1), the relationship between the amount of generated HF, CO ₂ , and CF ₄ gases and ΔO is expressed as the following equations (5), (6), and (7).

The oxygen concentration after discharge will be explained using these equations.
In the insulating gas, the total gas amount of gases such as N ₂ (nitrogen), CO ₂ (carbon dioxide), and Ar (argon) in the air is not affected by discharge, and is the same before and after discharge, and is expressed as _No. Note that CO ₂ in the air is different from CO ₂ in the generated gas shown in equations (1) and (6).
The total gas amount of the insulating gas after discharge is determined by the O ₂ gas amount O _i , the HFO gas amount HFO _i , the total gas amount N _o such as N ₂ , and the generated gas amount of HF, CO ₂ , and CF ₄ Therefore, the oxygen concentration m after discharge is expressed as the following equation (8).

式（３）～式（７）により、式（８）を式（９）のように表記できる。

Using equations (3) to (7), equation (8) can be expressed as equation (9).

式（９）に基づいて、ΔＯを次の式（１０）のように表記する。

Based on equation (9), ΔO is expressed as in equation (10) below.

式（４）、式（１０）により、ΔＨＦＯを次の式（１１）のように表記できる。

Using equations (4) and (10), ΔHFO can be expressed as shown in equation (11) below.

As mentioned above, the values of the coefficients a, b, c, d, and e are determined depending on the type of HFO. The O ₂ gas amount O _o in the insulating gas in the initial state, the HFO gas amount HFO _o , and the total gas amount N _o of N ₂ and the like are all known or measurable values. Therefore, according to equation (11), the amount of decrease ΔHFO in HFO due to discharge can be quantitatively evaluated by the oxygen concentration m in the insulating gas after discharge.

Next, using an insulating gas that is a mixture of HFO-1234yf, a type of hydrofluoroolefin gas, and air, we will insert specific coefficients into the above equation and calculate the amount of decrease ΔHFO of HFO-1234yf after discharge into the insulating gas. Calculated using the oxygen concentration m at

The chemical formula of HFO-1234yf is CF3CF=CH2. When a discharge test is performed in an atmosphere of an insulating gas mixed with HFO-1234yf and air, decomposition or oxidation of the insulating gas occurs. A chemical reaction between HFO-1234yf and O ₂ is caused, and HF, CO ₂ and CF ₄ are produced as main gases.
The chemical reaction formula in this case is shown by formula (12). Equation (12) is a chemical reaction equation in which each coefficient in Equation (1) is a=2, b=5, c=4, d=5, and e=1.

各係数、ａ＝２、ｂ＝５、ｃ＝４、ｄ＝５、ｅ＝１となるため、ΔＨＦＯと酸素濃度ｍとの関係について、式（１１）を次の式（１３）に書き換えられる。

Since each coefficient is a=2, b=5, c=4, d=5, and e=1, equation (11) can be rewritten into the following equation (13) regarding the relationship between ΔHFO and oxygen concentration m. .

仮に、ＨＦＯ―１２３４ｙｆのガス量ＨＦＯ_ｏが１０ｍｏｌに対して、空気のガス量が９０ｍｏｌで混合した絶縁ガスの場合に、放電によりＨＦＯ―１２３４ｙｆガスの減少量ΔＨＦＯ（単位ｍｏｌ）と酸素濃度ｍ（ｍｏｌ／ｍｏｌ、単位％）との関係を図１に示す。図１は、式（１３）に基づいて放電後のΔＨＦＯと酸素濃度ｍを計算した結果を示すΔＨＦＯと酸素濃度ｍとの相関関係を示す図である。

For example, in the case of an insulating gas in which the gas amount HFO _o of HFO-1234yf is 10 mol and the gas amount of air is 90 mol, the amount of decrease in HFO-1234yf gas due to discharge ΔHFO (unit: mol) and the oxygen concentration m ( mol/mol (unit: %) is shown in FIG. FIG. 1 is a diagram showing the correlation between ΔHFO and oxygen concentration m, which is a result of calculating ΔHFO and oxygen concentration m after discharge based on equation (13).

In FIG. 1, the initial state is indicated by point X _o and the state after discharge due to repeated discharge is indicated by point X ₅ .
As the number of discharges increases, the initial state _Xo changes to the post-discharge state _{X5 ,} as indicated by the arrow X. From the initial state _Xo to the post-discharge state _X5 , HFO-1234yf and _O2 react and are consumed by the discharge, the amount of gas of HFO-1234yf decreases, and the amount of decrease ΔHFO of HFO-1234yf shown on the vertical axis increases. The oxygen concentration m shown on the horizontal axis tends to decrease.

In the initial state X _o before discharge, the total amount of the entire insulating gas is 100 mol. The gas amount HFO- _1234yf in the insulating gas is 10 mol. Assuming that O ₂ in the air is 21%, the gas amount _{O 2} of O 2 in the initial state is 18.9 mol, and the oxygen concentration m in the insulating gas in the initial state is 18.9%. Note that since N _{2 ,} CO ₂ , Ar, etc. account for 79% of the air, the total gas amount N _o is 71.1 mol both before and after discharge.
As shown in FIG. 1, in the initial state _Xo , ΔHFO is 0 mol and the oxygen concentration m is 18.9%.

Based on equations (4) to (7), when 1 mol of HFO-1234yf is consumed by discharge and ΔHFO is 1 mol, the amount of decrease ΔO in O ₂ is 2.5 mol. 2 mol of HF, 2.5 mol of _CO2 , and 0.5 mol of _CF4 are generated. The total amount of produced gas is 5 mol.

The discharge continues further, resulting in the post-discharge state _X5 . Based on equations (4) to (7), when 5 mol of HFO-1234yf is consumed, 12.5 mol of O ₂ in the air is consumed. 10 mol of HF, 12.5 mol of _CO2 , and 2.5 mol of _CF4 are generated. A total of 17.5 mol of HFO-1234yf and O ₂ is consumed. The total amount of produced gas is 25 mol. The total amount of the entire insulating gas is 107.5 mol after discharge, compared to 100 mol at the initial stage.

Due to the discharge, 5 mol of HFO-1234yf is consumed from the initial 10 mol to 5 mol. ΔHFO is 5 mol. The gas concentration of HFO-1234yf becomes 4.65% (=5 mol/107.5 mol) after discharge, compared to 10% at the initial stage.
The amount of O ₂ becomes 6.4 mol because 12.5 mol of ΔO is consumed due to the discharge, compared to the initial 18.9 mol. The oxygen concentration m becomes 5.95% (=6.4 mol/107.5 mol) after discharge, compared to 18.9% at the initial stage.
As shown in FIG. 1, in state _X5 after discharge, ΔHFO is 5 mol and oxygen concentration m is 5.95%.

As shown in FIG. 1, there is a linear correlation between the amount of decrease ΔHFO of HFO-1234yf gas and the oxygen concentration m. HFO-1234yf and oxygen are consumed by the discharge, and generated gas such as decomposition gas is generated, and the total amount of insulating gas changes. Based on equation (13), from the oxygen concentration m in the insulating gas, ΔHFO can be estimated.
In the case of other types of HFO other than HFO-1234yf, ΔHFO can be similarly estimated from the oxygen concentration m in the insulating gas based on equation (11).

In this way, since the gas amount of the organic fluorine compound can be estimated from the oxygen concentration, there is a correlation between the oxygen concentration and the withstand voltage, and the degree of deterioration of the insulating gas can be evaluated based on the oxygen concentration in the insulating gas. Since the oxygen concentration is simply measured instead of the gas concentration of organic fluorine compounds, which cannot be measured accurately due to signal interference from decomposed gas, it is possible to improve the accuracy of evaluating the degree of deterioration of the insulating gas compared to conventional technology. .

The inventor of the present disclosure conducted a discharge test in a device simulating an actual gas insulated device using a gas mixture of a type of organic fluorine compound and dry air as an insulating gas, and measured the gas concentration of the organic fluorine compound after discharge by GC. - Quantitative analysis was performed using MS, and oxygen concentration was measured using a detection tube. As the number of discharges increases, a correlation that approximates a linear straight line is shown between the gas concentration of the organic fluorine compound and the oxygen concentration. This verified that the amount of organic fluorine compound in the insulating gas could be evaluated based on the oxygen concentration in the insulating gas.

In addition, the insulating gas that is a mixture of HFO and air produces CO (carbon monoxide), H ₂ O (water ) etc. may be generated. When the amount of CO, H ₂ O, etc. is very small compared to the ratio of the main generated gas in the mixed insulating gas, it is not necessary to consider the influence on the total gas amount of the insulating gas. In the above description, the correlation between the organic fluorine compound and the oxygen concentration is obtained without considering the influence of generated gases such as CO and H ₂ O.

On the other hand, depending on the type of organic fluorine compound, it may be necessary to consider the influence of generated gases such as CO and H ₂ O. Furthermore, depending on the type of adsorbent installed in the gas insulated equipment, decomposition gas generated from organic fluorine compounds and the like may be adsorbed. Since the amount of the entire insulating gas is affected by these gases, there is a possibility that there is no principled correlation as shown in equation (11).
However, in gas-insulated equipment, the organic fluorine compound gas and oxygen in the insulating gas react with each other due to discharge and are consumed. Therefore, the degree of deterioration of the insulating gas can be evaluated.

In order to improve the accuracy of evaluating the degree of deterioration of the insulating gas, it is desirable to measure the relationship between the degree of deterioration of the insulating gas and the state in which insulation performance can be ensured in advance using an actual gas insulated device or a device simulating the actual device. That is, it is desirable to measure in advance the relationship between the oxygen concentration, which reflects the amount of reduction in organic fluorine compound gas due to discharge, and the withstand voltage, which represents the insulation performance of the insulating gas.

Figure 2 shows the oxygen concentration and withstand voltage in the initial state before the start of use, and the oxygen concentration in the insulating gas through a discharge test simulating use for a certain period of time using an actual gas insulated equipment or a device that simulates the actual equipment. FIG. 2 is a conceptual diagram showing the relationship between withstand voltages.
In FIG. 2, the horizontal axis is the oxygen concentration m (unit: %), and the vertical axis is the withstand voltage V (unit: kv). Data showing the relationship between oxygen concentration m and withstand voltage V, shown in Figure 2, can be obtained by repeatedly filling an insulating gas mixture of an organic fluorine compound and dry air into a test chamber that simulates an actual gas insulated device. The number of discharges, current, and voltage are varied, and the withstand voltage V and oxygen concentration m are measured each time.

In FIG. 2, the initial state before discharge is indicated by point _Yo . Due to repeated discharges, the organic fluorine compound and oxygen in the insulating gas are consumed, the insulating gas deteriorates, and the insulation performance decreases. Point Y _th indicates the insulation performance lower limit state where the degree of deterioration of the insulation gas reaches the usage limit of the insulation gas that can ensure the required insulation performance.
As the number of discharges increases, as shown by arrow Y, the initial state Y _o changes to the insulation performance lower limit state Y _th . From the initial state Y _o to the insulation performance lower limit state Y _th , the oxygen concentration m shown on the horizontal axis decreases, and the withstand voltage V shown on the vertical axis tends to decrease.

In the initial state Y _o , the oxygen concentration is the initial oxygen concentration m _o and the corresponding withstand voltage is the initial withstand voltage V _o .
In the insulation performance lower limit state Y _th , the lower limit value of the withstand voltage indicating the lower limit state of the insulation performance is the withstand voltage threshold V _th , and the oxygen concentration in this state is the oxygen concentration threshold m _th . The oxygen concentration threshold m _th in this insulating gas is determined from the relationship between the withstand voltage and the oxygen concentration, and is the lower limit of the oxygen concentration that can ensure the necessary insulation performance. The withstand voltage threshold V _th is based on the specifications of the gas insulated equipment.

First, the initial withstand voltage V _o and the initial oxygen concentration m _o in the initial state Y _o are measured using an actual gas insulated equipment or a device simulating the actual equipment. Thereafter, repeated discharges are performed, and the withstand voltage V and oxygen concentration m after each discharge are measured. Based on the relationship between the withstand voltage V and the oxygen concentration m, an oxygen concentration threshold m _th corresponding to the withstand voltage threshold V _th is determined in advance.
In FIG. 2, in the insulation performance lower limit state Y _th , the value of the withstand voltage representing the lower limit state of the required insulation performance is the withstand voltage threshold V _th , and the oxygen concentration corresponding to the withstand voltage threshold V _th is the oxygen concentration threshold m _th. Become.

The measurement of the oxygen concentration m when determining the oxygen concentration threshold value m _th needs to be performed using the same measurement method as the oxygen concentration measurement performed for diagnosing the deterioration of the insulating gas in the actual usage state of the gas insulated equipment. This makes it possible to measure oxygen concentration while taking into account the effects of decomposed gas and adsorbents installed in gas insulated equipment, making it possible to improve the accuracy of evaluating the degree of deterioration of insulating gas under actual usage conditions. .
When diagnosing the deterioration of insulating gases used in gas-insulated equipment, the oxygen concentration m in the insulating gas is measured and compared with a pre-obtained oxygen concentration threshold m _th to ensure the required insulation performance of the insulating gas. Determine if it is possible.

Embodiments according to the present disclosure will be described below with reference to the drawings. Note that in each figure used in this specification, common elements are given the same reference numerals. Further, the present disclosure is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

Embodiment 1.
FIG. 3 is a configuration diagram showing the configuration of gas insulated equipment 1 according to Embodiment 1 of the present disclosure.
As shown in FIG. 3, the gas insulated equipment 1 includes a grounded tank 2 filled with a mixture of an organic fluorine compound and a gas containing oxygen such as air as an insulating gas, and a diagnostic device connected to the grounded tank 2. 3.
The gas insulated device 1 is, for example, a GIS (Gas Insulated Switchgear), and the ground tank 2 houses switching devices such as a disconnector and a circuit breaker.

For example, the grounded tank 2 may have a configuration in which a plurality of gas chambers are separated and filled with insulating gas. The insulating gas sealed in the grounded tank 2 will be described below as an example in which a mixture of air and hydrofluoroolefin gas, which is an organic fluorine compound gas, is used.
As the gas insulated equipment 1 is used, the amount of gas produced by decomposition or oxidation of hydrofluoroolefin gas generated by discharge increases, causing deterioration of the insulating gas. The diagnostic device 3 serves as a diagnostic device for the gas insulated equipment 1 that diagnoses the degree of deterioration of the insulating gas by measuring the oxygen concentration in the insulating gas sealed in the grounded tank 2.

An outflow valve 4 for taking out insulating gas for inspection is connected to the grounded tank 2. The diagnostic device 3 is connected to the grounded tank 2 via an outflow valve 4 . The outflow valve 4 is always closed except when the insulating gas sealed in the grounded tank 2 is allowed to flow out.
A flow rate adjustment valve 5 installed in the diagnostic device 3 is connected to the outflow valve 4 and adjusts the flow rate of the insulating gas flowing into the diagnostic device 3 from the grounded tank 2 via the outflow valve 4. Note that the flow rate adjustment valve 5 may be installed outside the diagnostic device 3 as long as it is connected to the outflow valve 4.
Furthermore, the diagnostic device 3 does not need to be connected to the ground tank 2 all the time. When measuring the oxygen concentration in the insulating gas sealed in the grounded tank 2, the diagnostic device 3 is connected to the grounded tank 2 via the outflow valve 4.

Next, the configuration of the diagnostic device 3 will be explained.
As shown in FIG. 3, the diagnostic device 3 includes an HF gas adsorption section 11, an organic gas adsorption section 12, an oxygen concentration measurement section 13, a diagnosis section 16, a flow meter 17, and a gas discharge port 18. It is being
The arrows shown in FIG. 3 represent the flow direction 6 of the insulating gas. In the diagnostic device 3, the insulating gas flowing out from the grounded tank 2 passes through the HF gas adsorption section 11 and the organic gas adsorption section 12, and then flows into the oxygen concentration measurement section 13 in that order. Further, the insulating gas flowing out from the oxygen concentration measurement section 13 flows into the flow meter 17 and is finally released into the atmosphere from the gas discharge port 18. Since the insulating gas is a mixture of an organic fluorine compound, which is advantageous in terms of global warming countermeasures, and a gas containing oxygen, such as air, it can be released into the atmosphere.

The oxygen concentration measurement unit 13 includes an oxygen measurement chamber 14 into which insulating gas flows, and an oxygen concentration meter 15 that is installed in the oxygen measurement chamber 14 and measures the oxygen concentration in the insulating gas. The oxygen concentration meter 15 of the oxygen concentration measuring section 13 uses, for example, a zirconia oxygen concentration meter.
By providing a gas discharge port 18 connected to the oxygen measurement chamber 14 via the flow meter 17, the pressure in the oxygen measurement chamber 14 is brought to atmospheric pressure. The insulating gas passes through the flowmeter 17 from the oxygen measurement chamber 14 and is released to the atmosphere from the gas discharge port 18, and the pressure of the insulating gas in the oxygen measurement chamber 14 is about 1 atm, similar to atmospheric pressure. Therefore, there is no need for calibration against the influence of atmospheric pressure, and the oxygen concentration in the insulating gas can be accurately measured by the oxygen concentration meter 15.

The diagnostic device 3 measures the oxygen concentration in the insulating gas flowing into the oxygen measuring chamber 14 of the oxygen concentration measuring section 13 using an oxygen concentration meter 15, and determines the degree of deterioration of the insulating gas based on the oxygen concentration measured by the diagnostic section 16. Determine.
The diagnosis unit 16 is connected to the oxygen concentration meter 15, and compares the measurement result of the oxygen concentration outputted from the oxygen concentration meter 15 with a predetermined oxygen concentration threshold m _th inputted in advance. Determine the degree of deterioration.

When the oxygen concentration is equal to or higher than the predetermined oxygen concentration threshold m _th , the diagnostic unit 16 determines that the degree of deterioration of the insulating gas is such that the required insulation performance can be ensured. That is, in this case, the diagnostic unit 16 determines that the insulating gas is still usable and has not reached its usage limit. On the other hand, when the oxygen concentration is lower than the predetermined oxygen concentration threshold m _th , the diagnostic unit 16 determines that the degree of deterioration of the insulating gas is such that the required insulation performance cannot be ensured. That is, in this case, the diagnostic unit 16 determines that the degree of deterioration of the insulating gas has reached its usage limit.
In addition, when the diagnostic unit 16 determines that the oxygen concentration is lower than the predetermined oxygen concentration threshold m _th and the degree of deterioration of the insulating gas is such that the required insulation performance cannot be secured, the degree of deterioration of the insulating gas has reached its usage limit. It is possible to send an alarm.

Further, the diagnostic unit 16 can calculate an oxygen concentration deterioration value Z indicating the degree of deterioration of the insulating gas using equation (14).

酸素濃度劣化値Ｚ（単位％）は、初期状態となるガス絶縁機器使用前の絶縁ガスにおける初期酸素濃度ｍ_ｏと酸素濃度閾値ｍ_ｔｈとの差に対する酸素濃度ｍと酸素濃度閾値ｍ_ｔｈとの差の割合である。診断部１６は、酸素濃度劣化値Ｚに基づいて、絶縁ガスの劣化度合の判定処理を行う。

The oxygen concentration deterioration value Z (unit: %) is the difference between the oxygen concentration m and the oxygen concentration threshold m _th with respect to the difference between the initial oxygen concentration m _o in the insulating gas before using the gas insulated equipment and the oxygen concentration threshold m _th . This is the percentage of difference. The diagnostic unit 16 performs a process of determining the degree of deterioration of the insulating gas based on the oxygen concentration deterioration value Z.

In the initial state, the oxygen concentration m is the initial oxygen concentration m _o , so Z=100%, and when the oxygen concentration m decreases to the oxygen concentration threshold m _th , Z=0%. The smaller the oxygen concentration deterioration value Z, the closer the degree of deterioration of the insulating gas is to a state where necessary insulation performance cannot be secured.
The oxygen concentration deterioration value Z itself may be displayed, or the meaning of the numerical value of the oxygen concentration deterioration value Z may be displayed in several categories. These display methods make it easier to intuitively understand the degree of deterioration of the insulating gas.
For example, when Z = 100 to 40%, "Normal" is displayed, when Z = 40 to 20%, "Maintenance time is approaching" is displayed, and when Z = 20 to 0%, "Maintenance is approaching" is displayed. If Z is 0% or less, it can display the message "Please stop the equipment and perform maintenance immediately." If necessary, the determination conditions may be divided into a plurality of categories to display the degree of deterioration of the insulating gas. In this way, the degree of deterioration of the insulating gas can be displayed based on the comparison result of the oxygen concentration m with the initial oxygen concentration m _o and the oxygen concentration threshold m _th instead of the comparison of the oxygen concentration m with the oxygen concentration threshold m _th . I can do it.

Next, the HF gas adsorption section 11 and the organic gas adsorption section 12, which are adsorption sections provided in the diagnostic device 3, will be explained.
The HF gas adsorption unit 11 serves as an HF gas adsorption unit that adsorbs HF gas, which is a decomposed gas of hydrofluoroolefin gas contained in the insulating gas, from an HF gas adsorption material. The organic gas adsorption unit 12 serves as an organic gas adsorption unit that adsorbs the organic gas contained in the insulating gas using an organic gas adsorbent. It is preferable that the insulating gas, which is a mixture of hydrofluoroolefin gas and air, passes through the HF gas adsorption section 11 and the organic gas adsorption section 12, and then the oxygen concentration is measured by the oxygen concentration measurement section 13.
The HF gas, which is the decomposed gas of the hydrofluoroolefin gas, damages the probe of the oxygen concentration meter 15, so it is removed in advance by the HF gas adsorption unit 11. The HF gas adsorption section 11 is filled with an adsorbent that adsorbs HF gas, such as calcium oxide (CaO) particles, in order to remove HF gas from the decomposed gas.

Furthermore, an oxidation reaction may occur in the organic fluorine compound in the insulating gas due to the heat of the probe of the oxygen concentration meter 15, and oxygen may be consumed. Since it affects the measurement accuracy of the oxygen concentration in the actual insulating gas, it is removed in advance by the organic gas adsorption unit 12.
The organic gas adsorption unit 12 is filled with an organic gas adsorbent, such as zeolite or activated carbon, that adsorbs organic gas contained in the insulating gas.
Here, the organic gas includes an organic fluorine compound that is a component of the insulating gas, an organic gas in the decomposition gas of the organic fluorine compound, and an organic substance in the impurity gas. For example, when the organic fluorine compound in the insulating gas is a hydrofluoroolefin gas, the hydrofluoroolefin gas, CF4 in the cracked gas, and the organic matter in the impurity gas in the mixed insulating gas are organic gases, and the organic gas adsorption unit Remove at 12.

Further, in order to prevent damage to zeolite and the like packed in the organic gas adsorption unit 12 due to HF gas, it is preferable to allow the insulating gas to pass through the HF gas adsorption unit 11 before the organic gas adsorption unit 12 . For this reason, an organic gas adsorption unit 12 is provided between the HF gas adsorption unit 11 and the oxygen concentration measurement unit 13, and after the HF gas in the insulating gas collected from the grounded tank is adsorbed by the HF gas adsorption material, The organic gas in the insulating gas is adsorbed by the organic gas adsorbent.
Note that the oxygen concentration meter 15 of the oxygen concentration measuring section 13 can accurately measure the oxygen concentration in the insulating gas even if the remaining insulating gas from which the HF gas and the organic gas have been removed is a mixed gas.

A flow meter 17 is connected to the oxygen concentration measuring section 13 in the flow direction 6 . For example, an integrating flowmeter is used as the flowmeter 17.
Before the insulating gas flows into the diagnostic device 3 from the grounded tank 2, residual gas exists in gaps between the connection tube from the outflow valve 4 to the oxygen concentration measuring section 13, the adsorption section, and the like. To measure insulating gas, it is necessary to replace the residual gas in these gaps with insulating gas. For this reason, the oxygen concentration is measured by the oxygen concentration measuring section 13 after the insulating gas containing residual gas at least equal to or more than the volume of these gaps is discharged to the atmosphere.

In order to confirm that the insulating gas supplied to the oxygen concentration measuring section 13 for oxygen concentration measurement does not contain residual gas, the flow meter 17 measures the insulating gas flowing out from the oxygen measuring chamber 14 of the oxygen concentration measuring section 13. Measure the gas flow rate. The outflow amount (in m 3 ) of the insulating gas flowing out from the oxygen measurement chamber 14 is determined from the product of the measured flow rate (in m ³ /s) of the insulating gas and the outflow time (in ^s ). The amount of insulating gas flowing out from the oxygen measuring chamber 14 is greater than the volume of these gaps, confirming complete outflow of the insulating gas including residual gas.

In the diagnostic device 3 shown in FIG. 3, the flow meter 17 is provided between the oxygen measurement chamber 14 and the gas discharge port 18, and measures the flow rate of the insulating gas flowing into the oxygen measurement chamber 14, and measures the flow rate of the insulating gas flowing into the oxygen measurement chamber 14. It also measures the flow rate of insulating gas released from 18.
Note that since there is no difference in the flow rate of the insulating gas before and after the oxygen measurement chamber 14, the flowmeter 17 may be installed between the oxygen measurement chamber 14 and the adsorption section.
Further, the flow meter 17 may be installed on the upstream side of the adsorption section in the insulating gas flow direction 6, for example, between the flow rate adjustment valve 5 and the HF gas adsorption section 11. At this time, it is necessary to make the flow meter 17 of a material that will not be damaged by the generated gas contained in the insulating gas, and to take into account the reduction in flow rate due to gas adsorption in the adsorption section.

Next, the connection relationship of each component in the diagnostic device 3 will be explained.
As shown in FIG. 3, the grounded tank 2 and the HF gas adsorption section 11 of the diagnostic device 3 are connected via an outflow valve 4, a flow rate adjustment valve 5, a first connection tube 31, and a first valve 32.
The HF gas adsorption section 11 and the organic gas adsorption section 12 of the diagnostic device 3 are connected via a second valve 33, a second connection tube 34, and a third valve 35.
The organic gas adsorption section 12 and the oxygen concentration measurement section 13 are connected via a fourth valve 36 and a third connection tube 37.
The oxygen concentration measuring section 13 and the flow meter 17 are connected via a fourth connecting tube 38.

The plurality of valves provided in the diagnostic device 3 are for isolating components. The first valve 32 and the second valve 33, which are provided before and after the HF gas adsorption unit 11, are kept closed except when in use, so that the HF gas adsorbent packed into the HF gas adsorption unit 11 can be closed. can be isolated from the outside air to prevent deterioration of adsorption performance due to deterioration of the adsorbent. In addition, by keeping the third valve 35 and fourth valve 36 provided before and after the organic gas adsorption unit 12 in a closed state except when in use, the zeolite or activated carbon packed in the organic gas adsorption unit 12 is Decrease in adsorption performance due to deterioration can be prevented.

Although the valves provided between each part of the diagnostic device 3 may be provided as necessary, they may be omitted depending on the connection configuration. For example, when the HF gas adsorption unit 11 and the organic gas adsorption unit 12 are integrated and separated from each other, the second valve 33 and the third valve between the HF gas adsorption unit 11 and the organic gas adsorption unit 12 At least one of 35 can be omitted.

Next, a diagnostic method for diagnosing the degree of deterioration of the insulating gas in the gas insulated equipment 1 will be described using FIG. 4.
FIG. 4 shows the flow of a diagnostic process for implementing a diagnostic method for measuring the oxygen concentration in an insulating gas and diagnosing the degree of deterioration of the insulating gas by the diagnostic device 3, which is a diagnostic device for the gas insulated equipment 1 according to the first embodiment. FIG.

Before starting the work of diagnosing the degree of deterioration of the insulating gas in the gas insulated equipment 1, the outflow valve 4 and the flow rate adjustment valve 5 are closed. When the work starts, the diagnostic process for the gas insulated equipment 1 moves to step S1.
In step S1, the first valve 32, second valve 33, third valve 35, and fourth valve 36 are opened to allow the insulating gas sealed in the grounded tank 2 to flow into the diagnostic device 3.

Next, the diagnostic process for the gas insulated equipment 1 moves to step S2.
In step S2, the outflow valve 4 is first opened, and then the flow rate adjustment valve 5 is opened while being adjusted to allow the insulating gas sealed in the grounded tank 2 to flow into the diagnostic device 3.
At this time, while checking the flow rate of the insulating gas measured by the flow meter 17, the flow rate adjustment valve 5 is adjusted so that the flow rate of the insulating gas becomes a predetermined flow rate. Here, the predetermined flow rate is, for example, an optimized gas supply amount to increase the adsorption efficiency by the HF gas adsorption unit 11 and the organic gas adsorption unit 12.

Next, the diagnostic process for the gas insulated equipment 1 moves to step S3.
In step S3, the process waits until a predetermined standby time elapses to allow the insulating gas to flow into the diagnostic device 3. The HF gas in the insulating gas is adsorbed by the HF gas adsorbent from the grounded tank 2 to the diagnostic device 3, and the organic gas in the insulating gas is adsorbed by the organic gas adsorbent, and then the insulating gas is transferred to the diagnostic device 3. Let it flow.
At this time, the system waits until the remaining gas in the gap between the connection tube from the outflow valve 4 to the oxygen concentration measuring section 13, the adsorption section, etc. is completely replaced with the insulating gas. Based on the flow rate of the insulating gas flowing out from the oxygen measuring chamber 14 measured by the flow meter 17, complete outflow of the insulating gas including residual gas is confirmed. In this way, the flow rate of the insulating gas supplied to the oxygen measuring chamber 14 is measured, and after confirming that the insulating gas whose oxygen concentration is to be measured does not contain any residual gas, the next step is to measure the oxygen concentration m. Proceed to step.
Steps S1 to S3 are gas sampling steps for sampling insulating gas from the grounded tank 2.

Next, the diagnostic process for the gas insulated equipment 1 moves to step S4.
Step S4 is an oxygen concentration measuring step in which the oxygen concentration m in the insulating gas flowing into the oxygen concentration measuring section 13 is measured.
The insulating gas flowing out from the grounded tank 2 flows into the HF gas adsorption section 11 via the outflow valve 4, the flow rate adjustment valve 5, the first connection tube 31, and the first valve 32. HF gas is removed from the insulating gas from the adsorbent in the HF gas adsorption section 11 . Subsequently, the insulating gas flowing out from the HF gas adsorption section 11 flows into the organic gas adsorption section 12, where the organic gas is removed from the adsorbent.

After the insulating gas containing the residual gas is released into the atmosphere, the insulating gas not containing the residual gas that flows into the oxygen measurement chamber 14 is the remaining insulating gas from which the HF gas and the organic gas have been removed. The oxygen concentration m in the remaining insulating gas can be measured with high precision by the oxygen concentration meter 15 installed in the oxygen measurement chamber 14.
After the oxygen concentration m in the insulating gas is measured by the oxygen concentration measuring section 13, the insulating gas flowing out from the oxygen concentration measuring section 13 passes through the flow meter 17 and is released into the atmosphere from the gas discharge port 18.

After completing the measurement of the oxygen concentration m, the diagnostic processing of the gas insulated equipment 1 moves to step S5 and step S6, respectively.
In step S5, the outflow valve 4 and the flow rate adjustment valve 5 are closed. Step S6 is a diagnostic step in which it is determined whether the degree of deterioration of the insulating gas is such that necessary insulation performance cannot be ensured. There is no restriction on the order of steps S5 and S6, and they may be executed after the oxygen concentration measurement step is completed.

In step S6, the oxygen concentration m measured in step S4 is input to the diagnostic section 16. The diagnostic unit 16 compares the measured oxygen concentration m with an oxygen concentration threshold value m _th that has been input in advance, and executes a process for determining the degree of deterioration of the insulating gas.
If m≧m _th and the oxygen concentration m is greater than or equal to the oxygen concentration threshold m _th , the diagnostic unit 16 determines that the degree of deterioration of the insulating gas is such that the required insulation performance can be ensured, and proceeds to step S7. In step S7, it is shown that the insulating gas can be continued to be used, for example, a sign saying "continuous use of the insulating gas" is transmitted.
Further, if m<m _th and the oxygen concentration m is smaller than the predetermined oxygen concentration threshold m _th , the diagnostic unit 16 determines that the degree of deterioration of the insulating gas is such that the required insulation performance cannot be secured, and moves to step S8. do. In step S8, as an alarm transmission step for transmitting an alarm indicating that the degree of deterioration of the insulating gas has reached its usage limit, for example, a sign "insulating gas replacement" is transmitted to urge replacement of the insulating gas.
Furthermore, the diagnostic unit 16 may calculate the oxygen concentration deterioration value Z using equation (14), and display the degree of deterioration of the insulating gas in a plurality of categories based on the oxygen concentration deterioration value Z.
This completes the insulating gas diagnostic process for the gas insulated device 1.

As mentioned above, the withstand voltage V and the oxygen concentration m were measured in a state where a discharge test was performed simulating a predetermined usage period using the gas insulated equipment 1 or a device simulating the gas insulated equipment 1, and the withstand voltage The oxygen concentration threshold m _th corresponding to the withstand voltage threshold V _th is determined in advance from the relationship between V and the oxygen concentration m. The measurement of the oxygen concentration m is performed under the same measurement conditions as the method of measuring the oxygen concentration m in the actual usage state of the gas insulated device 1.
That is, in the case of Embodiment 1, the insulating gas from which the HF gas and organic gas have been removed is brought to a state of about 1 atm, and the oxygen concentration m in the insulating gas is measured with an oxygen concentration meter in the oxygen measurement chamber, and the withstand voltage is determined. The oxygen concentration threshold value m _th is determined in advance along with the measurement data of .

In the case of the first embodiment, the insulating gas flowing into the oxygen measurement chamber 14 is a gas from which HF gas and organic gas have been removed. Therefore, the oxygen concentration is measured by the oxygen concentration meter 15 by measuring the oxygen concentration in the insulating gas from which the HF gas and organic gas have been removed. In this case, the amount of reduction in organic fluorine compound gas due to discharge can be quantitatively evaluated by the oxygen concentration m in the insulating gas from which HF gas and organic gas have been removed.
For example, when using an insulating gas that is a mixture of hydrofluoroolefin gas and gas containing air, ΔHFO can be determined by the oxygen concentration m using equation (11) and setting the coefficients c=0 and e=0. can be evaluated.

The timing for implementing the diagnostic method for diagnosing the degree of deterioration of the insulating gas in the gas insulated equipment 1 can be at regular inspection timing such as an annual inspection, or whenever there is a symptom of deterioration in insulation performance. .
Furthermore, the diagnostic device 3 may be set each time it is necessary to check the withstand voltage, or may be permanently installed in the gas insulated equipment 1. In the case of a permanent installation, the outflow valve 4, flow rate adjustment valve 5, etc. are remotely operated, and the value of the flow rate of the insulating gas measured by the flow meter 17 and the value of the oxygen concentration measured by the oxygen concentration measuring section 13 are measured in real time. By receiving the signal remotely, it is possible to check the withstand voltage remotely. This makes it possible to quickly check the withstand voltage of gas-insulated equipment from various companies around the world from a single maintenance company location. Furthermore, when diagnosing deterioration of the insulating gas at a site where the gas insulating equipment 1 is installed, the operator can perform the process even if he or she does not have specialized knowledge such as analytical techniques. This makes it possible to improve the efficiency of diagnosing the degree of deterioration of the insulating gas.

According to the gas insulated equipment diagnostic device and the gas insulated equipment diagnostic method according to the first embodiment, in order to evaluate the degree of deterioration of the insulating gas sealed in the gas insulated equipment by measuring the oxygen concentration in the insulating gas, Compared to the conventional technology, it is possible to avoid the inability to accurately measure the gas concentration of the organic fluorine compound due to signal interference from the decomposed gas, and it is possible to improve the accuracy of evaluating the degree of deterioration of the insulating gas.
According to the gas insulated equipment using the diagnostic method according to the first embodiment, an insulating gas containing a mixture of an organic fluorine compound, which is advantageous in terms of global warming countermeasures, and a gas containing oxygen, such as air, is used and sealed in the gas insulated equipment. In order to evaluate the degree of deterioration of the insulating gas sealed in gas-insulated equipment by measuring the oxygen concentration in the insulating gas, compared to conventional technology, the gas concentration of organic fluorine compounds can be measured by signal interference from decomposed gas. Inability to measure accurately can be avoided, and the accuracy of evaluating the degree of deterioration of the insulating gas can be improved. Furthermore, it is possible to improve the efficiency of diagnosing the degree of deterioration of the insulating gas.

Embodiment 2.
In the second embodiment, the same reference numerals are used for the same components as in the first embodiment of the present disclosure, and descriptions of the same or corresponding parts are omitted. Hereinafter, gas insulated equipment 100 according to Embodiment 2 will be described with reference to the drawings.

FIG. 5 is a configuration diagram showing the configuration of gas insulated equipment 100 according to Embodiment 2 of the present disclosure. In order to measure the oxygen concentration in the insulating gas sealed in the gas insulated equipment, an oxygen concentration meter is used in the first embodiment, whereas a gas detection tube is used in the gas insulated equipment 100 according to the second embodiment. It will be done.
As shown in FIG. 5, the gas insulated device 100 includes a ground tank 2 filled with insulating gas and a diagnostic device 103 connected to the ground tank 2.

The diagnostic device 103 serves as a diagnostic device for the gas insulated equipment 100 that diagnoses the degree of deterioration of the insulating gas by measuring the oxygen concentration in the insulating gas sealed in the grounded tank 2.
Diagnostic device 103 is connected to grounded tank 2 via outflow valve 4 . The diagnostic device 103 includes a gas sampling section 50 and an oxygen concentration measuring section 60 that measures oxygen concentration.

A flow rate adjustment valve 5 installed in the diagnostic device 103 is connected to the outflow valve 4 and adjusts the flow rate of the insulating gas flowing into the diagnostic device 103 from the grounded tank 2 via the outflow valve 4. Note that the flow rate adjustment valve 5 may be installed outside the diagnostic device 103 as long as it is connected to the outflow valve 4.
Further, in FIG. 5, an arrow indicates a flow direction 56 of the insulating gas. The insulating gas flows from the grounded tank 2 to the gas sampling section 50 and further to the oxygen concentration measuring section 60.

The gas sampling section 50 is provided with a gas sampling bag 21 for sampling insulating gas. Since the gas sampling bag 21 is flexible, the pressure of the insulating gas flowing into the gas sampling bag 21 is 1 atmosphere, which is the same as the surrounding atmosphere. The pressure of the insulating gas supplied to the gas detection tube 22 is 1 atm, and there is no influence due to pressure difference, so the gas detection tube 22 can accurately measure the oxygen concentration.

The oxygen concentration measuring section 60 includes a gas detection tube 22 for measuring oxygen concentration and a suction device 23 for sucking insulating gas. The gas detection tube 22 is, for example, Gas Tech Gas Detection Tube No. 31B is used. This gas detection tube detects the oxygen concentration in the insulating gas, even if in addition to the oxygen to be measured, hydrofluoroolefin gas, which is an organic fluorine compound gas, and decomposition gas of the organic fluorine compound gas, etc. coexist in the insulating gas. can be measured. The suction device 23 is provided at the tip of the gas detection tube 22 in the flow direction 56 of the insulating gas so as to suck the insulating gas into the gas detection tube 22 .

The grounded tank 2 and the gas sampling bag 21 of the gas sampling section 50 are connected via an outflow valve 4, a flow rate adjustment valve 5, a sampling bag connection tube 41, and a sampling bag inflow valve 42.
The gas sampling bag 21 and the gas detection tube 22 are connected via a sampling bag outflow valve 43 and a detection tube connection tube 44.

Furthermore, the diagnostic device 103 includes a diagnostic section 26 . The diagnostic unit 26 determines the degree of deterioration of the insulating gas based on the oxygen concentration measured by the gas detection tube 22. The oxygen concentration measured by the gas detection tube 22 is input into the diagnostic section 26 automatically or manually by an operator who performs the diagnostic process. If the measured oxygen concentration is equal to or higher than a predetermined oxygen concentration threshold, the diagnostic unit 26 determines that the degree of deterioration of the insulating gas is in a state where the necessary insulation performance can be ensured, and if the oxygen concentration is lower than the predetermined oxygen concentration threshold, It is determined that the degree of deterioration of the insulating gas is such that the necessary insulation performance cannot be secured.
In addition, when the diagnostic unit 26 determines that the oxygen concentration is lower than a predetermined oxygen concentration threshold and the degree of deterioration of the insulating gas is such that the required insulation performance cannot be secured, the diagnostic unit 26 determines that the degree of deterioration of the insulating gas has reached its usage limit. An alarm can be sent.
Further, similarly to the diagnosis unit 16 according to the first embodiment, the diagnosis unit 26 calculates the oxygen concentration deterioration value Z using equation (14), and divides the oxygen concentration into a plurality of categories based on the oxygen concentration deterioration value Z. The degree of deterioration of the insulating gas may also be displayed.

Note that, similarly to the first embodiment, the diagnostic device 103 does not need to be permanently installed in the gas-insulated equipment 100, and can be set each time a withstand voltage confirmation operation is required.
Further, the gas sampling section 50 and the oxygen concentration measuring section 60 do not need to be in a constant state of connection. In this case, the insulating gas is sampled using the gas sampling bag 21 while the gas sampling section 50 is connected to the grounded tank 2. After the collection of insulating gas from the grounded tank 2 is completed, the gas sampling bag 21 is removed from the grounded tank 2, and as shown in FIG. 6, the oxygen concentration is measured by connecting it to the gas detection tube 22 of the oxygen concentration measuring section 60. I can do it.
As shown in FIG. 6, the gas sampling bag 21 of the gas sampling section 50 can be taken out with a sampling bag inflow valve 42 and a sampling bag outflow valve 43 attached to both ends. For example, after each insulating gas is sampled from a plurality of grounded tanks using a gas sampling bag, the oxygen concentration can be measured all at once using a gas detection tube. Thereby, it is possible to improve the efficiency of diagnosing the degree of deterioration of the insulating gas of gas-insulated equipment.

Next, a diagnosis method for diagnosing the degree of deterioration of the insulating gas in the gas insulated equipment 100 will be described using FIG. 7.
FIG. 7 is a diagram showing a flow of a diagnostic process for implementing a diagnostic method for diagnosing the degree of deterioration of the insulating gas of the gas insulated device 100 according to the second embodiment. In FIG. 7, insulating gas is sampled by the gas sampling bag 21 of the gas sampling section 50 with the gas sampling section 50 and the oxygen concentration measuring section 60 initially not connected. This figure shows the flow of connecting the gas sampling section 50 and the oxygen concentration measuring section 60 to measure the oxygen concentration after the sampling of the insulating gas is completed.

Before starting the diagnostic process for the insulating gas of the gas insulated device 100, the outflow valve 4 and the flow rate adjustment valve 5 are in a closed state. When the work is started, the diagnostic process for the gas insulated equipment 100 moves to step S11.
In step S11, preparations are made to cause the insulating gas sealed in the grounded tank 2 to flow into the gas sampling bag 21. Therefore, the collection bag inflow valve 42 is opened and the collection bag outflow valve 43 is closed.

Next, the insulating gas diagnosis processing moves to step S12.
In step S12, the outflow valve 4 is first opened, and then the flow rate adjustment valve 5 is opened while being adjusted to cause the insulating gas sealed in the grounded tank 2 to flow into the gas sampling bag 21. After inflating the gas sampling bag 21, the flow rate adjustment valve 5 is temporarily closed.

Next, the insulating gas diagnosis process moves to step S13.
In step S13, the sampling bag outflow valve 43 is opened, and the insulating gas containing air remaining in the gas sampling bag 21 is released. S12 and S13 are steps for removing air remaining in the gas sampling bag 21. The air remaining in the gas sampling bag 21 may be removed by repeating S12 and S13 multiple times. Alternatively, the air remaining in the gas sampling bag 21 may be pushed out manually.

Next, the insulating gas diagnosis process moves to step S14.
In step S14, the sampling bag outflow valve 43 is closed, the flow rate adjustment valve 5 is adjusted and opened, and the insulating gas sealed in the grounded tank 2 is caused to flow into the gas sampling bag 21 and sampled. After filling the gas sampling bag 21 with a predetermined volume of insulating gas, the outflow valve 4, flow rate adjustment valve 5, and sampling bag inflow valve 42 are closed. Here, the predetermined capacity is greater than the capacity of the gas used when measuring the oxygen concentration with the gas detection tube 22. For example, it is twice the capacity of the gas used when measuring the oxygen concentration with the gas detection tube 22.
Steps S11 to S14 are gas sampling steps for sampling insulating gas from the grounded tank 2.

Next, the process proceeds to an oxygen concentration measuring step in which the oxygen concentration in the insulating gas collected in the gas sampling bag 21 is measured. The insulating gas diagnosis process moves to step S15.
In step S15, as shown in FIG. Connect to gas detection tube 22.

Next, the insulating gas diagnosis processing moves to step S16.
In step S16, the insulating gas collected in the gas sampling bag 21 is sucked using the suction device 23 attached to the gas detection tube 22, and the insulating gas is caused to flow into the gas detection tube 22. Pull the suction device 23 in advance to create a vacuum inside. With the collection bag inflow valve 42 closed, the collection bag outflow valve 43 is opened, and the insulating gas flows from the gas collection bag 21 to the gas detection tube 22 until the inside of the suction device 23 returns to atmospheric pressure. Fill with insulating gas.
In FIG. 6, arrows indicate a flow direction 66 in which the insulating gas collected in the gas sampling bag 21 flows into the gas detection tube 22.

Next, the insulating gas diagnosis processing moves to step S17.
Step S17 is an oxygen concentration measuring step in which the oxygen concentration m in the insulating gas flowing into the gas detection tube 22 is measured.

After completing the measurement of the oxygen concentration m, the insulating gas diagnostic process moves to step S18.
Step S18 is a diagnostic step in which it is determined whether the degree of deterioration of the insulating gas is such that necessary insulation performance cannot be ensured. In step S18, the oxygen concentration m measured in step S17 is input to the diagnostic section 26. The diagnostic unit 26 compares the measured oxygen concentration m with an oxygen concentration threshold value m _th that has been input in advance, and executes a process for determining the degree of deterioration of the insulating gas. The determination process performed by the diagnosis unit 26 is similar to the process performed by the diagnosis unit 16 in the first embodiment.

Furthermore, steps S19 and S20 after step S18 are the same as steps S7 and S8 in the first embodiment, respectively, and therefore their description will be omitted.
This completes the insulating gas diagnostic process for the gas insulated device 100.

In Embodiment 2, as in Embodiment 1, withstand voltage V and oxygen concentration are determined in a state in which a discharge test is performed simulating a predetermined period of use using gas insulated equipment 100 or a device simulating gas insulated equipment 100. m is measured, and an oxygen concentration threshold m th corresponding to the withstand voltage threshold V _th is determined in advance from the relationship between the withstand voltage V and the oxygen concentration _m . The measurement of the oxygen concentration m is performed under the same measurement conditions as the method of measuring the oxygen concentration m in the actual usage state of the gas insulated device 100. That is, in the case of the second embodiment, insulating gas is collected from the grounded tank 2 using a gas sampling bag, and the oxygen concentration m in the insulating gas is measured using a gas detection tube. The threshold value m _th is determined in advance.

In the second embodiment, the insulating gas measured by the gas detection tube is similar to the insulating gas sealed in the grounded tank 2 without removing HF gas and organic gas. For this reason, for example, when an insulating gas that is a mixture of hydrofluoroolefin gas and air-containing gas is used in the gas insulated equipment 100, ΔHFO can be quantitatively evaluated by the oxygen concentration m using equation (11).

According to the gas insulated equipment diagnostic apparatus and the gas insulated equipment diagnostic method according to the second embodiment, the same effects as in the first embodiment are achieved.

Note that the configuration shown in the above embodiments shows an example of the contents of the present disclosure, and can be combined with other known techniques. For example, the insulating gas collected with a gas sampling bag may be passed through an HF adsorption section and an organic gas adsorption section, and then measured using an oxygen concentration meter in an oxygen measurement chamber of an oxygen concentration measurement section. At this time, in order to send the insulating gas in the gas sampling bag to the oxygen measuring chamber, pressure may be applied to the gas sampling bag or the insulating gas may be sucked from the oxygen concentration measuring section. It is also possible to omit or change a part of the configuration without departing from the gist of the present disclosure.

1, 100 gas insulated equipment, 2 ground tank, 3, 103 diagnostic device, 4 outflow valve, 5 flow rate adjustment valve, first current mirror circuit, 5 second current mirror circuit, 6, 56, 66 flow direction, 11 HF gas Adsorption unit, 12 Organic gas adsorption unit, 13, 60 Oxygen concentration measurement unit, 14 Oxygen measurement chamber, 15 Oxygen concentration meter, 16, 26 Diagnosis unit, 17 Flow meter, 18 Gas discharge port, 21 Gas sampling bag, 22 Gas detection Pipe, 23 Aspirator, 32 First valve, 33 Second valve, 35 Third valve, 36 Fourth valve, 41 Collection bag connection tube, 42 Collection bag inflow valve, 43 Collection bag outflow valve, 50 Gas sampling section

Claims (23)

A diagnostic device for gas insulated equipment having a grounded tank filled with a mixture of an organic fluorine compound and a gas containing oxygen as an insulating gas,
an oxygen concentration measurement unit that measures the oxygen concentration in the insulating gas collected from the grounded tank;
The oxygen concentration is compared with a pre-input oxygen concentration threshold, and if the oxygen concentration is greater than or equal to the oxygen concentration threshold, it is determined that the degree of deterioration of the insulating gas is in a state where the required insulation performance can be ensured, and the oxygen a diagnostic unit that determines that the degree of deterioration of the insulating gas is such that necessary insulation performance cannot be secured when the concentration is lower than the oxygen concentration threshold;
A diagnostic device for gas insulated equipment. The diagnosis unit calculates an oxygen concentration deterioration value indicating the degree of deterioration of the insulating gas, and displays the degree of deterioration of the insulating gas based on the oxygen concentration deterioration value,
The oxygen concentration deterioration value is a ratio of the difference between the oxygen concentration and the oxygen concentration threshold to the difference between the initial oxygen concentration, which is the oxygen concentration in the insulating gas in an initial state, and the oxygen concentration threshold. The diagnostic device for gas insulated equipment according to claim 1. further comprising a gas sampling section provided with a gas sampling bag for sampling the insulating gas from the grounded tank,
3. The diagnostic apparatus for gas insulated equipment according to claim 1, wherein the insulating gas is supplied from the gas sampling section to the oxygen concentration measuring section. HF that is connected to the oxygen concentration measuring section and filled with an HF gas adsorbent that adsorbs HF gas contained in the insulating gas before the insulating gas collected from the grounded tank flows into the oxygen concentration measuring section. The diagnostic device for gas insulated equipment according to any one of claims 1 to 3, further comprising a gas adsorption section. An organic gas adsorbent that is connected to the oxygen concentration measuring section and filled with an organic gas adsorbent that adsorbs organic gas contained in the insulating gas before the insulating gas collected from the grounded tank flows into the oxygen concentration measuring section. The diagnostic device for gas insulated equipment according to any one of claims 1 to 4, further comprising a gas adsorption section. The organic gas adsorption unit is provided between the oxygen concentration measurement unit and an HF gas adsorption unit filled with an HF gas adsorbent that adsorbs HF gas contained in the insulating gas collected from the grounded tank. The diagnostic device for gas insulated equipment according to claim 5, characterized in that: The oxygen concentration measuring section includes:
an oxygen measurement chamber into which the insulating gas flows;
The diagnostic device for gas insulated equipment according to any one of claims 1 to 6, further comprising an oxygen concentration meter that is installed in the oxygen measurement chamber and measures the oxygen concentration in the insulating gas. 8. The diagnostic device for gas insulated equipment according to claim 7, further comprising a gas discharge port connected to the oxygen measurement chamber and discharging the insulating gas flowing out from the oxygen measurement chamber to the atmosphere. The diagnostic device for gas insulated equipment according to any one of claims 1 to 8, further comprising a flow meter connected to the oxygen concentration measuring section and measuring a flow rate of the insulating gas flowing out from the oxygen concentration measuring section. The oxygen concentration measuring section includes:
a gas detection tube for measuring oxygen concentration in the insulating gas collected from the grounded tank;
a suction device connected to the gas detection tube and sucking the insulating gas into the gas detection tube;
The diagnostic device for gas insulated equipment according to any one of claims 1 to 6, characterized in that it has the following. A method for diagnosing gas insulated equipment having a grounded tank filled with a mixture of an organic fluorine compound and a gas containing oxygen as an insulating gas, the method comprising:
a gas sampling step of sampling the insulating gas from the grounded tank;
an oxygen concentration measuring step of measuring the oxygen concentration in the insulating gas;
The oxygen concentration is compared with a pre-input oxygen concentration threshold, and if the oxygen concentration is greater than or equal to the oxygen concentration threshold, it is determined that the degree of deterioration of the insulating gas is in a state where the required insulation performance can be ensured, and the oxygen a diagnosing step of determining that the degree of deterioration of the insulating gas is such that necessary insulation performance cannot be secured if the concentration is lower than the oxygen concentration threshold;
A method for diagnosing gas insulated equipment. The oxygen concentration threshold is determined based on the relationship between the oxygen concentration of the insulating gas collected in the gas sampling step using the same measurement method as in the oxygen concentration measuring step and the withstand voltage of the insulating gas. The method for diagnosing gas insulated equipment according to claim 11. In the diagnosis step, calculating an oxygen concentration deterioration value indicating the degree of deterioration of the insulating gas, and displaying the degree of deterioration of the insulating gas based on the oxygen concentration deterioration value;
The oxygen concentration deterioration value is a ratio of the difference between the oxygen concentration and the oxygen concentration threshold to the difference between the initial oxygen concentration, which is the oxygen concentration in the insulating gas in an initial state, and the oxygen concentration threshold. The method for diagnosing gas-insulated equipment according to item 11 or 12. 14. The method for diagnosing gas insulated equipment according to claim 11, wherein in the gas sampling step, the insulating gas is sampled from the grounded tank using a gas sampling bag. 15. The gas insulated device according to claim 11, wherein in the gas sampling step, HF gas contained in the insulating gas sampled from the grounded tank is adsorbed by an HF gas adsorbent. Diagnostic method. 16. The gas insulated equipment according to claim 11, wherein in the gas sampling step, an organic gas contained in the insulating gas sampled from the grounded tank is adsorbed by an organic gas adsorbent. Diagnostic method. In the gas sampling step, the HF gas contained in the insulating gas collected from the grounded tank is adsorbed by an HF gas adsorbent, and then the organic gas is adsorbed by the organic gas adsorbent. The method for diagnosing gas insulated equipment according to claim 16. 18. In the oxygen concentration measuring step, the oxygen concentration in the insulating gas is measured by an oxygen concentration meter installed in an oxygen measurement chamber into which the insulating gas flows. Diagnosis method for gas insulated equipment. 19. The method for diagnosing gas insulated equipment according to claim 18, wherein the insulating gas flowing out of the oxygen measurement chamber is released into the atmosphere to make the pressure in the oxygen measurement chamber similar to atmospheric pressure. The method for diagnosing gas insulated equipment according to claim 18 or 19, characterized in that the flow rate of the insulating gas flowing out from the oxygen measurement chamber is measured by a flow meter. In the oxygen concentration measuring step, the insulating gas collected in the gas sampling step is sucked into a gas detection tube using a suction device, and the oxygen concentration in the insulating gas is measured using the gas detection tube. The method for diagnosing gas insulated equipment according to any one of claims 11 to 17. It has a grounded tank filled with a gas mixture of an organic fluorine compound and a gas containing oxygen as an insulating gas, and the insulating method is performed using the method for diagnosing gas insulated equipment according to any one of claims 11 to 21. Gas insulation equipment that diagnoses whether the degree of gas deterioration is sufficient to maintain the required insulation performance. 23. The gas insulated device according to claim 22, wherein the organic fluorine compound is a hydrofluoroolefin.

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