WO2016038908A1

WO2016038908A1 - Gas leak detection device and gas leak inspection method

Info

Publication number: WO2016038908A1
Application number: PCT/JP2015/056282
Authority: WO
Inventors: 稲波　久雄; 廣瀬　誠
Original assignee: 株式会社日立製作所
Priority date: 2014-09-09
Filing date: 2015-03-04
Publication date: 2016-03-17
Also published as: JP2016057135A

Abstract

Provided is a gas leak detection device capable of carrying out temperature correction of gas pressure in consideration of the influence of energization conditions and environmental factors and highly accurately detecting a gas leak. A gas leak detection device is provided with: a pressure sensor 10; a temperature sensor 11; a current data acquisition unit 6 for acquiring a current value; a storage unit 20 for storing a measured gas pressure value, measured surface temperature value, and the current value; a data storage unit 30 in which the relationship between an average internal gas temperature and surface temperature corresponding to the current value is stored in a database beforehand; a comparison unit 41 for calculating an average internal gas temperature from the surface temperature stored in the storage unit 20; a pressure calculation unit 42 for correcting the gas pressure stored in the storage unit 20 to a gas pressure value at a reference temperature; and an evaluation unit 43 for subjecting the corrected gas pressure to linear regression and evaluating whether the slope of the resulting regression line exceeds the slope of a gas leak of a specified concentration.

Description

Gas leak detection device and gas leak inspection method

The present invention relates to a gas leak detection device and detection method for a gas insulated electrical device that detects a minute leak of an insulating gas sealed in a closed container such as a gas insulated switchgear.

A gas-insulated switchgear is an equipment that instantaneously cuts off current to protect substation equipment when an abnormal current flows due to lightning. The gas insulated switchgear has a structure in which a plurality of gas pressure vessels are connected, and a circuit breaker and a disconnecting device are accommodated together with an inert gas in the gas pressure vessel. As the inert gas sealed in the gas pressure vessel, sulfur hexafluoride (hereinafter abbreviated as SF6) is used. SF ₆ is subject to management because its global warming potential is as high as 24,000 times that of CO ₂ , and gas leak detection of gas-insulated electrical equipment is required.

In order to detect a gas leak, that is, to monitor the amount of gas over time, it is common to measure the gas pressure. However, since the gas pressure largely fluctuates depending on the temperature, correction is made to convert it to the gas pressure at the reference temperature of 20 ° C.

Patent Document 1 describes a technique related to conventional gas leak detection. This document shows a method of measuring the external temperature of a gas pressure vessel and correcting the gas pressure after a predetermined time from the time when the temperature is measured by the measured temperature.

Further, Patent Document 2 describes a technique related to conventional gas leak detection. This document shows a method of measuring the temperature inside and outside the gas pressure vessel and correcting the temperature of the internal gas pressure in a time zone in which the difference between the two temperatures is small.

JP 2010-193616 A JP 2011-130581 A

In the method disclosed in Patent Document 1, the relationship between the external temperature of the gas pressure vessel and the gas pressure is related by a delay time, and the gas pressure is corrected by the external temperature. However, it is difficult to make a one-to-one correspondence between the external temperature and the gas pressure, and an error tends to occur in the gas pressure corrected using the external temperature.

In Patent Document 2, since the temperature measurement inside the gas pressure vessel is performed at one place, the temperature distribution caused by energization or gas convection cannot be accurately shown. Further, since the gas insulated switchgear is composed of a plurality of gas pressure vessels, it is not realistic from the viewpoint of installation cost to install temperature sensors inside all the gas pressure vessels and measure the internal temperature.

Furthermore, Patent Document 1 and Patent Document 2 do not consider the influence of wind that greatly affects the temperature inside the gas pressure vessel.

Therefore, the object of the present invention has been made in view of such circumstances, and the temperature correction of the gas pressure is performed in consideration of the energization condition and the influence of the wind that have a large effect on the internal temperature of the gas pressure vessel. An object of the present invention is to provide a gas leak detection device that can detect a gas leak with high accuracy.

The gas leak detection device of the present invention includes a pressure sensor that measures the gas pressure of a gas pressure vessel, a temperature sensor that measures the surface temperature of the gas pressure vessel, and a current that takes in a current value that flows through a bus arranged in the gas pressure vessel. A data capture unit, a gas pressure measurement value, a recording unit for recording the measurement value and current value of the surface temperature of the gas pressure vessel, and an internal gas average temperature and gas pressure vessel of the gas pressure vessel according to the range of the current value The data storage unit in which the relationship with the surface temperature is previously databased, and the relationship between the average internal gas temperature stored in the data storage unit and the surface temperature corresponding to the current value recorded in the recording unit are extracted. The reference unit for calculating the internal gas average temperature of the gas pressure vessel from the surface temperature of the gas pressure vessel recorded in the recording unit, and the gas pressure recorded in the recording unit using the internal gas average temperature A pressure calculation unit that corrects the gas pressure value of the gas and a test unit that performs linear regression on the corrected gas pressure and tests whether the slope of the regression line obtained thereby exceeds the slope of the gas leak at the specified concentration. It is characterized by points.

According to the present invention, it is possible to provide a gas leak detection device capable of detecting gas leak of SF ₆ with high accuracy by performing temperature correction of gas pressure in consideration of the influence of energization conditions and environmental factors.

The block diagram of the gas leak detection apparatus which concerns on 1st embodiment. The block diagram which shows the detection flow of the gas leak which concerns on 1st embodiment. The figure which shows an example of the database memorize | stored in a data storage part. The figure which shows an example of the flow velocity vector inside a gas pressure vessel. The drawing is simplified and only the right half of the gas pressure vessel is shown. The figure which shows the method of calculating | requiring the average temperature inside a gas pressure vessel. The figure which shows the time-dependent change of measurement pressure and correction pressure. The figure which shows the time transition at night of the standard deviation of correction | amendment gas pressure. The figure which shows filtering of the gas pressure data which concern on 1st embodiment. The figure which shows the linear regression of correction | amendment gas pressure. The figure which shows the inclination of the regression line of correction | amendment gas pressure. The block diagram of the gas leak detection apparatus which concerns on 2nd embodiment. The block diagram of the gas leak detection apparatus which concerns on 3rd embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiments described later are merely examples, and combinations of the embodiments, combinations with known or well-known techniques, and other modes by replacement are possible.

FIG. 1 shows a configuration of a gas leak detection apparatus according to the first embodiment. FIG. 2 is a block diagram showing a gas leak detection flow. FIG. 3 is a diagram illustrating an example of a database stored in the data storage unit. FIG. 4 is a velocity vector diagram showing an example of the flow inside the gas pressure vessel. FIG. 5 is a diagram showing a method for obtaining the average temperature inside the gas pressure vessel. FIG. 6 is a diagram showing a change with time of the measurement pressure and the correction pressure. FIG. 7 is a diagram showing a time transition of the standard deviation of the correction gas pressure at night. FIG. 8 is a diagram illustrating filtering of gas pressure data according to the first embodiment. FIG. 9 is a diagram showing linear regression of the corrected gas pressure. FIG. 10 is a diagram showing the slope of the regression line of the correction gas pressure.

As shown in FIG. 1, the gas-insulated switchgear 1 has a structure in which a plurality of gas pressure vessels 2a to 2c are connected, and a bus bar 5 penetrates the central portion in the same direction as these gas pressure vessels. ing. The value of the current flowing through the bus 5 is sent to the recording unit 20 via the current data capturing unit 6 as information from the substation protection control system.

Insulating gas SF ₆ having a predetermined gas pressure is sealed in the gas pressure vessels 2a to 2c. Since the gas pressure is monitored for each of the gas pressure vessels 2a to 2c, the gas pressure sensors 10a to 10c are connected via the pipes 3a to 3c and the valves 4a to 4c. These gas pressure sensors 10a to 10c measure the gas pressure inside the gas pressure vessels 2a to 2c.

Temperature sensors 11a to 11c are installed on the surfaces of the gas pressure vessels 2a to 2c, and the surface temperatures of the gas pressure vessels 2a to 2c are measured. In consideration of the influence of direct sunlight, it is preferable to measure the surface temperature in the area on the ground side half of the gas pressure vessel, and it is more preferable to measure the surface temperature at the bottom of the gas pressure vessel.

Information on the gas pressure sensors 10a to 10c and the temperature sensors 11a to 11c is sent to the recording unit 20.

The data storage unit 30 stores a relationship between the average internal gas temperature of the gas pressure vessel and the surface temperature as a database.

The calculation unit 40 includes a verification unit 41, a pressure calculation unit 42, and a test unit 43.

The collation unit 41 is connected to the recording unit 20 and the data storage unit 30. In the collation unit 41, the relationship between the internal gas average temperature and the surface temperature of the gas pressure vessel corresponding to the current value recorded in the recording unit 20 is extracted from the data storage unit 30 and the gas pressure vessel recorded in the recording unit 20. The average internal gas temperature of the gas pressure vessels 2a to 2c is determined from the surface temperature of 2a to 2c.

The pressure calculation unit 42 uses the internal gas average temperature to correct the gas pressure in the gas pressure vessels 2a to 2c recorded in the recording unit 20 to the gas pressure at the reference temperature (for example, 20 ° C.). The verification unit 43 verifies whether the time-dependent change in the gas pressure whose temperature has been corrected as described above (hereinafter referred to as the corrected gas pressure) exceeds the gas leak of the specified concentration.

In the display unit 50, a change with time of the correction gas pressure is shown.

Next, a gas leak detection flow will be described with reference to FIG.

(step 1)
The gas pressures in the gas pressure vessels 2a to 2c are measured by the gas pressure sensors 10a to 10c. Further, the surface temperature of the gas pressure vessels 2a to 2c is measured by the temperature sensors 11a to 11c. At this time, by setting the temperature sensor at the bottom of the gas pressure vessel, it is possible to obtain a surface temperature that is not easily affected by sunlight.

(Step 2)
The gas pressure inside the gas pressure vessel and the surface temperature of the gas pressure vessel measured in step 1 are sent to the recording unit 20, and the gas pressure and the surface temperature of the gas pressure vessel are recorded in the recording unit 20 in time series. The value of the current flowing through the bus 5 is also sent to the recording unit 20 and recorded along with the gas pressure and temperature.

(Step 3)
In the data storage unit 30, the relationship between the average temperature inside the gas pressure vessel and the surface temperature as shown in FIG. 3 is stored as a database according to the range of the energization condition (current value I). This database can be created using a commercially available fluid analysis code. Here, the temperature inside the gas pressure vessel is preferably not an average but a mean value at a plurality of locations. This is because the gas pressure is proportional to the average value of the gas temperature. However, the following considerations are preferable when calculating the average temperature inside the gas pressure vessel.

FIG. 4 shows an example of the flow of the insulating gas inside the gas pressure vessel. In FIG. 4, the drawing is simplified and only the right half of the cross section is shown. An upward flow is generated on the surface of the bus bar, and a circulating flow is formed by natural convection in which it flows downwards so as to follow the tube wall of the gas pressure vessel and then rises again. Furthermore, a vortex separated from the circulating flow is generated near the equator (center part in the figure). Due to the influence of the separation vortex, the temperature fluctuation in the vicinity of the equator of the gas pressure vessel is large. Therefore, it is preferable to exclude the temperature in the vicinity of the equator when calculating the average temperature inside the gas pressure vessel. That is, the average of the temperatures at the top and bottom of the gas pressure vessel is preferably the internal average temperature, and the average of four or more locations excluding the vicinity of the equator is more preferably the internal average temperature.

The collation unit 41 collates the energization conditions in the database of the data storage unit 30 corresponding to the current value I recorded in the recording unit 20.

(Step 4)
In the verification unit 41, the relationship between the average temperature inside the gas pressure vessel and the surface temperature corresponding to the verified energization conditions is extracted (see FIG. 3).

(Step 5)
In the verification unit 41, the internal average temperature is calculated from the surface temperature of the gas pressure vessel as shown in FIG. 5 based on the relationship between the extracted average temperature inside the gas pressure vessel and the surface temperature.

(Step 6)
In the pressure calculation part 42, the gas pressure of the recording part 20 is temperature-corrected using the internal average temperature. The temperature correction of the gas pressure is converted into the gas pressure at the reference temperature of 20 ° C. using, for example, the equation of state of the real gas shown in Equation (1), Beattie-Bridgeman.

Here, p ₀ is the gas pressure (Pa), v is the molar volume (m ³ / mol), R is the gas constant (8.31 J / mol · K), T is the gas temperature (K), and the formula (1 ) A and B are shown below.

A = 15.78 × 10 ^-1 (1-0.1062 × 10 ^-3 / v) (2)
B = 0.366 × 10 ^-3 (1-0.1236 × 10 ^-3 / v) (3)

(Step 7)
An example of the gas pressure change whose temperature is corrected in step 6 is shown in FIG. By performing temperature correction, large pressure fluctuations due to temperature changes are greatly reduced. However, minute pressure fluctuations still remain. This is because the pressure fluctuation during the daytime affected by sunlight is large.

Therefore, the pressure calculation unit 42 filters the pressure data. FIG. 7 shows an example in which the standard deviation of the corrected gas pressure at night after sunset is obtained at one hour intervals. The standard deviation here is a measure for seeing fluctuations in the correction gas pressure. In FIG. 7, when several hours have passed since sunset, it can be seen that the standard deviation becomes less than half of that immediately after sunset and becomes stable. FIG. 8 shows an example in which corrected gas pressure data is extracted in a time zone (for example, nighttime from 23:00 to 5:00) that is less than half of the standard deviation of the corrected gas pressure immediately after sunset.

By extracting only the data of the time zone with a small standard deviation of the correction gas pressure, that is, the night time zone that is not affected by sunlight, the fluctuation of the correction gas pressure is smoothed. I understand that Therefore, it is effective to use only the corrected gas pressure data in the time zone that is less than half of the standard deviation of the corrected gas pressure immediately after sunset as filtering to reduce the minute pressure fluctuation that remains after pressure correction. It can be said.

(Step 8)
The verification unit 43 determines whether the corrected gas pressure filtered in step 7 corresponds to a gas leak having a specified concentration or more. First, the regression data of the correction gas pressure with time is linearly regressed. The linear regression of the pressure data is performed by, for example, the least square method. Specifically, as shown in FIG. 9, the gas pressure (Y-axis) is plotted against time (X-axis), and a regression is made to a straight line y = ax + b. Here, by displaying the change with time and the regression line of the corrected gas pressure on the display unit 50, the administrator can easily recognize the state of the gas pressure vessel.

(Step 9)
After linear regression of the pressure data in step 8, the slope a of the regression line y = ax + b is recorded in the test unit 43 once a day. As shown in FIG. 10, the verification unit 43 stores in advance the slope c of the allowable gas leak concentration line. Therefore, the test unit 43 compares the slope a of the regression line updated daily and the slope c of the allowable gas leak line to determine the presence or absence of a gas leak.

(Step 10)
If the slope a of the regression line of the pressure data exceeds the slope c of the allowable gas leak line in step 9, it is determined as a gas leak and an alarm is issued.

According to the first embodiment, the gas condition is calculated after calculating the internal gas temperature using the relation between the internal gas temperature and the surface temperature stored in advance in the database in consideration of energization conditions that greatly affect the internal temperature of the gas pressure vessel. Since the pressure is corrected, it is possible to provide a gas leak detection device with higher accuracy than the pressure correction using the conventional surface temperature.

FIG. 11 shows another embodiment of the present invention. In this embodiment, a weather data server 7 for storing weather data transmitted from a local weather station is provided in order to obtain wind speed information around the gas pressure vessel.

Local weather stations send out wind speed and weather (sunshine) at regular intervals as weather statistics information. The meteorological statistical information is fetched into the meteorological data server 7 and the fetched information is transferred to the recording unit 20. By creating a database of the relationship between the internal gas temperature of the gas pressure vessel and the surface temperature in consideration of the effects of wind speed and sunlight, it is possible to calculate the internal gas temperature with higher accuracy in consideration of the effects of wind and sunlight. It becomes possible.

An anemometer may be installed instead of the weather data server 7. Further, as described in the first embodiment, when only nighttime pressure data having a small standard deviation of the correction gas pressure is used, a configuration in which the weather information is not captured may be employed.

As described above, the basic structure is the same as that of the first embodiment, and the relation between the internal gas temperature and the surface temperature of the gas pressure vessel in consideration of the wind speed and sunshine is stored in a database in advance. By using the meteorological data, it is possible to consider the influence of wind and sunshine on the gas pressure vessel, and it is possible to perform more accurate gas pressure temperature correction.

FIG. 12 shows another embodiment of the present invention. The present embodiment is different from the first embodiment in that the measured data is sent wirelessly to a remote place and the gas pressure is managed at a point away from the gas insulated switchgear 1.

FIG. 12 shows a gas leak detection apparatus according to the third embodiment. The basic structure is the same as that of the first embodiment. A feature of the third embodiment is that a transmitter 21 is installed in the recording unit 20 and a receiver 45 is installed in the calculation unit 40.

The information of the gas pressure sensors 10a to 10c, the temperature sensors 11a to 11c, and the information of the weather data server 7 recorded in the recording unit 20 are wirelessly skipped from the transmitter 21. The arithmetic unit 40 and the data storage unit 30 are located away from the gas insulated switchgear 1 and monitor gas leaks in the gas pressure vessel. In the substation equipment, there is a problem of surge resistance, but by placing the calculation unit 40 in a place away from the gas-insulated switchgear 1, it is possible to take a surge countermeasure. In addition, it has an advantage that information on gas pressures of a plurality of gas insulated switchgears 1 can be managed collectively at a distance.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

1 ... Gas insulated switchgear, 2a, 2b, 2c ... Gas pressure vessel, 3a, 3b, 3c ... Piping, 4a, 4b, 4c ... Valve, 5 ... Busbar, 6 ... Current data capturing unit, 7 ... Weather data server, 10a, 10b, 10c ... Gas pressure sensor, 11a, 11b, 11c ... Temperature sensor, 20 ... Recording unit, 21 ... Transmitter , 30 ... Data storage unit, 40 ... Calculation unit, 41 ... Verification unit, 42 ... Pressure calculation unit, 43 ... Testing unit, 45 ... Receiver, 50 ... Display Part,

Claims

A pressure sensor for measuring the gas pressure in the gas pressure vessel;
A temperature sensor for measuring the surface temperature of the gas pressure vessel;
A current data capturing section for capturing a current value flowing through a bus arranged in the gas pressure vessel;
A recording unit for recording the measured value of the gas pressure, the measured value of the surface temperature of the gas pressure vessel, and the current value;
A data storage unit in which a relation between the internal gas average temperature of the gas pressure vessel and the surface temperature of the gas pressure vessel corresponding to the range of the current value is stored in a database;
The surface of the gas pressure vessel recorded in the recording unit is extracted by extracting a relationship between the internal gas average temperature stored in the data storage unit and the surface temperature corresponding to the current value recorded in the recording unit. A collation unit that calculates the internal gas average temperature of the gas pressure vessel from the temperature;
A pressure calculation unit that corrects the gas pressure recorded in the recording unit to a gas pressure value of a reference temperature using the internal gas average temperature;
A linear regression of the corrected gas pressure, and a test unit that tests whether the slope of the regression line obtained thereby exceeds the slope of the gas leak at the specified concentration;
Gas leak detection device with
The gas leak inspection apparatus according to claim 1,
Furthermore, it has a meteorological data server that stores wind speed from the meteorological data of the area where the gas pressure vessel is located
The recording unit further records the wind speed,
In the data storage unit, the relationship between the internal gas average temperature of the gas pressure vessel and the surface temperature of the gas pressure vessel according to the current value and the range of the wind speed is databased in advance.
The collation unit extracts a relationship between the internal gas average temperature stored in the data storage unit and the surface temperature corresponding to the current value and wind speed recorded in the recording unit, and is recorded in the recording unit. The internal gas average temperature of the gas pressure vessel is calculated from the surface temperature of the gas pressure vessel.
The gas leak inspection apparatus according to claim 1.
The internal gas average temperature of the gas pressure vessel stored in the data storage unit is an average of the top and bottom temperatures inside the gas pressure vessel,
The gas leak detection apparatus according to claim 1.
The internal gas average temperature of the gas pressure vessel stored in the data storage unit is an average of the top and bottom temperatures inside the gas pressure vessel,
The gas leak detection apparatus according to claim 2.
The internal gas average temperature of the gas pressure vessel stored in the data storage unit is an average of a plurality of four or more locations excluding the vicinity of the equator of the gas pressure vessel,
The gas leak detection apparatus according to claim 1.
The internal gas average temperature of the gas pressure vessel stored in the data storage unit is an average of a plurality of four or more locations excluding the vicinity of the equator of the gas pressure vessel,
The gas leak detection apparatus according to claim 2.
The surface temperature of the gas pressure vessel is a value measured in a region on the ground side half of the gas pressure vessel,
The gas leak detection apparatus according to claim 1.
The surface temperature of the gas pressure vessel is a value measured in a region on the ground side half of the gas pressure vessel,
The gas leak detection apparatus according to claim 2.
The surface temperature of the gas pressure vessel is measured at the bottom of the gas pressure vessel,
The gas leak detection apparatus according to claim 1.
The surface temperature of the gas pressure vessel is measured at the bottom of the gas pressure vessel,
The gas leak detection apparatus according to claim 2.
The recording unit has a transmitter that wirelessly skips data recorded in the recording unit,
The arithmetic unit has a receiver for receiving the data,
The gas leak detection apparatus according to claim 1.
The recording unit has a transmitter that wirelessly skips data recorded in the recording unit,
The arithmetic unit has a receiver for receiving the data,
The gas leak detection apparatus according to claim 2.
A gas leak inspection method using the gas leak detection device according to claim 1,
After correcting the gas pressure to the gas pressure value of the reference temperature in the arithmetic unit, using the corrected gas pressure data in the time zone that is less than half of the standard deviation of the corrected gas pressure immediately after sunset, the correction It is characterized by performing the linear regression of the gas pressure data and judging whether or not there is a gas leak by judging whether or not the slope of the regression line obtained thereby exceeds the slope of the gas leak straight line of the specified allowable concentration,
Gas leak inspection method.
A gas leak inspection method using the gas leak detection device according to claim 2,
After correcting the gas pressure to the gas pressure value of the reference temperature in the arithmetic unit, using the corrected gas pressure data in the time zone that is less than half of the standard deviation of the corrected gas pressure immediately after sunset, the correction It is characterized by performing the linear regression of the gas pressure data and judging whether or not there is a gas leak by judging whether or not the slope of the regression line obtained thereby exceeds the slope of the gas leak straight line of the specified allowable concentration,
Gas leak inspection method.
In the method of detecting gas leak from the gas pressure vessel by measuring the gas pressure in the gas pressure vessel,
Measure the gas pressure in the gas pressure vessel with a pressure sensor,
Measuring the surface temperature of the gas pressure vessel with a temperature sensor;
The current value flowing through the bus arranged in the gas pressure vessel is acquired through a current data capturing unit,
The relationship between the internal gas average temperature of the gas pressure vessel corresponding to the current value and the surface temperature of the gas pressure vessel is extracted from a database created in advance,
Using the relationship between the internal gas average temperature and the surface temperature in the database, the internal gas average temperature is calculated from the measured surface temperature of the gas pressure vessel,
Correcting the measured gas pressure using the calculated internal gas average temperature to the gas pressure at the reference temperature,
The corrected gas pressure is linearly regressed, and the presence or absence of gas leak is determined by determining whether or not the slope of the regression line obtained thereby exceeds the slope of the gas leak straight line of the prescribed allowable concentration.
Gas leak inspection method.