SF6 gas filling measurement method for GIS device

Abstract

The application discloses a GIS device SF6 gas filling measurement method, which can track the environmental and pipeline temperature changes in real time, heat the gas in the pipeline by a multi-stage fuzzy temperature control module before the gas is filled into the gas chamber, and lock the gas at the current environmental temperature, so as to reduce the gas filling error and the gas volume calculation error, and can improve the accuracy of the measurement result by calculating the cumulative flow.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical equipment, in particular to a SF6 gas charging measurement method for GIS equipment. BACKGROUND

[0002] The SF6 gas volume and the effective volume of the closed space of the GIS equipment are basic data for accounting carbon emissions of power grid enterprises, and how to accurately obtain the data is a research difficulty in the field. Field operation personnel generally choose to obtain the data by calculating the pressure difference before and after charging in the charging operation. However, the temperature of the gas charged into the gas chamber is generally low due to the influence of phase change of SF6 gas cylinder, and it changes to the ambient temperature all the time. According to the Beattie-Bridgman gas state equation, this brings trouble to the accurate measurement of the above data. SUMMARY

[0003] Therefore, it is necessary to provide a SF6 gas charging measurement method for GIS equipment.

[0004] A SF6 gas charging measurement method for GIS equipment, comprising the following steps:

[0005] S1, before charging, the gas temperature T0 and the pressure P0 in the gas chamber are measured by an environment temperature sensor and an environment pressure sensor respectively, and the SF6 gas density ρ0 of the closed space before charging is calculated by the Beattie-Bridgman gas state equation;

[0006] S2, during the charging process, the gas temperature T p and the gas temperature T i in the pipeline are measured by an environment temperature sensor and a pipeline temperature sensor respectively, and the pipeline is temperature-regulated before the gas is charged into the gas chamber by a multi-stage fuzzy temperature control module according to the difference ΔT i between the two;

[0007] S3, the instantaneous output flow q and the output time t are measured by a mass flow meter, the total flow Q is calculated by a cumulative flow integral algorithm, and the supplemented SF6 gas volume ΔV is calculated by integration;

[0008] S4, the SF6 gas density ρ t at 20℃ and standard atmospheric pressure is calculated by the Beattie-Bridgman gas state equation, the SF6 gas density ρ t is multiplied by the SF6 gas volume ΔV to calculate the supplemented SF6 gas mass Δm;

[0009] S5. After inflation is completed, the density ρ1 of SF6 gas in the gas chamber after inflation is calculated using the Beattie-Bridgman gas state equation based on the measured data T1 and P1 from the ambient temperature sensor and ambient pressure sensor.

[0010] S6, the effective volume V of the enclosed space is obtained through the formula... get;

[0011] S7. Multiply the SF6 gas density ρ1 in the closed space and the effective volume V of the closed space to calculate the SF6 gas volume m1 after inflation.

[0012] Preferably, in steps S1, S4, and S5, the Beattie-Bridgman gas law is formulated as follows:

[0013] P=(RTB-A)ρ2+RTρ

[0014] A=73.882×10-5-5.132105×10-7ρ

[0015] B=2.50695×10-3-2.12283×10-6ρ

[0016] R = 56.9502 × 10⁻⁵

[0017] Where T is the gas temperature measured by the ambient temperature sensor, P is the pressure measured by the ambient pressure sensor, and ρ is the SF6 gas density.

[0018] Preferably, in step 2, the multi-level fuzzy temperature control module consists of three temperature control modules, three pipe temperature sensors, and three temperature control modules connected in series on the pipe in an alternating manner. The three pipe temperature sensors and three temperature control modules are respectively the first pipe temperature sensor, the first temperature control module, the second pipe temperature sensor, the second temperature control module, the third pipe temperature sensor, and the third temperature control module.

[0019] Preferably, the input to the first temperature control module is the temperature T in the air chamber measured by the ambient temperature sensor. p The gas temperature T inside the pipe measured by the first pipe temperature sensor i1 The difference ΔT i1 The difference ΔT i1 The value range of is E1[0,45]. This range is divided into 3 smaller intervals: E 11 [0,15), E 12 [15,30), E 13 [30,45], and E 11 E 12 E 13 Corresponding to heat source temperature T 11 T12 , T 13 , T 11 < T 12 < T 13 ;

[0020] The input of the second temperature control module is the difference ΔT p between the temperature T i2 measured by the ambient temperature sensor in the gas chamber and the temperature T i2 measured by the second pipeline temperature sensor in the pipeline, the value range of the difference ΔT i2 is E2[-7.5, 7.5], and the range is evenly divided into three small ranges: E 21 [-7.5, -1], E 22 [-1, 1], and E 23 [1, 7.5], and E 21 , E 22 , and E 23 correspond to the heat source temperatures T 21 , T 22 , and T 23 , respectively, wherein T 21 < T 22 < T 23 ;

[0021] The input of the third temperature control module is the difference ΔT p between the temperature T i3 measured by the ambient temperature sensor in the gas chamber and the temperature T i3 measured by the third pipeline temperature sensor in the pipeline, the value range of the difference ΔT i3 is E3[-2, 2], and the range is evenly divided into three small ranges: E 31 [-2, -1], E 32 [-1, 1], and E 33 [1, 2], and E 31 , E 32 , and E 33 correspond to the heat source temperatures T 31 , T 32 , and T 33 , respectively, wherein T 31 < T 32 < T 33 .

[0022] Preferably, the heat source temperature parameters of the three temperature control modules are selected as shown in the matrix Tij:

[0023]

[0024] wherein T ij is in ℃, and the values of i and j are both {1, 2, 3}.

[0025] Preferably, in step 3, all the instantaneous output flow data measured by the mass flow meter is summarized to obtain a smooth straight line, and according to the geometric meaning of definite integral, the cumulative flow in the time period [a, b] can be obtained by calculating the area of the curved graph surrounded by the curve q=q(t), the straight line t=a, the straight line t=b and the time axis t.

[0026] Preferably, several sub-points a=t 0< t1<t2<…t n-1 <t n =b are inserted in the time interval [a, b] to divide the interval [a, b] into n small intervals [t i -1, t i ], with length The cumulative flow in the time interval Δt i is obtained by calculating the area of the i-th small curved trapezoid, and the area of the i-th small curved trapezoid is

[0027] If the instantaneous flow acquisition rate is infinitely magnified, n tends to infinity, and the total flow

[0028] Preferably, the volume ΔV of the additional SF6 gas is obtained by the formula .

[0029] In the SF6 gas charging measurement method of the GIS device, on the one hand, by tracking the changes of the environment and the pipeline temperature in real time, the gas in the pipeline is heated and locked at the current environment temperature by the multi-stage fuzzy temperature control module before the gas is filled into the gas chamber, so as to reduce the charging error and the gas volume calculation error; on the other hand, by calculating the cumulative flow, the accuracy of the measurement result is improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] Fig. 1 is a schematic diagram of the connection structure of the gas charging measurement device. Figure 1 Fig. 2 is a schematic diagram of the instantaneous flow and time collected by the mass flow meter.

[0031] Fig. 3 is a schematic diagram of the connection structure of the pipeline temperature sensor and the multi-stage fuzzy temperature control module. Figure 2 Fig. 4 is an effect diagram of the multi-stage fuzzy temperature control.

[0032] Fig. 5 is a schematic diagram of the connection structure of the pipeline temperature sensor and the multi-stage fuzzy temperature control module. Figure 3 Fig. 6 is an effect diagram of the multi-stage fuzzy temperature control.

[0033] Fig. 7 is a schematic diagram of the connection structure of the pipeline temperature sensor and the multi-stage fuzzy temperature control module. Figure 4 Fig. 8 is an effect diagram of the multi-stage fuzzy temperature control.

[0034] In the figure: GIS device gas chamber 1, SF6 gas cylinder 2, ambient temperature sensor 3, pressure sensor 4, mass flow meter 5, solenoid valve 6, first pipe temperature sensor 71, second pipe temperature sensor 72, third pipe temperature sensor 73, first temperature control module 81, second temperature control module 82, third temperature control module 83, lock temperature sensor 9. DETAILED DESCRIPTION

[0035] To achieve the SF6 gas volume and effective volume data in the process of inflation, combined with Figure 1 As shown, the inflation measuring device is connected in series between the inflation pipeline, the inlet is connected to the SF6 gas cylinder 2 with pressure reducing valve, and the outlet is connected to the GIS device gas chamber 1 inflation and deflation interface. After the inflation pipeline is checked for airtightness, the SF6 gas cylinder 2 valve is opened, the inflation measuring device is started, the inflation is stopped to the target pressure, and the SF6 gas volume and the effective volume of the closed space in the GIS device are calculated and output.

[0036] The inflation measuring device mainly includes an ambient temperature sensor 3, an ambient pressure sensor 4 and a mass flow meter 5. The ambient temperature sensor 3 and the ambient pressure sensor 4 accurately measure the temperature and pressure inside the gas chamber before and after inflation. The mass flow meter 5 measures the amount of gas charged during inflation. The GIS device 1 gas volume and gas chamber volume data are obtained by calculating the amount of gas charged and the temperature and pressure change data before and after inflation. In addition, an automatic regulating solenoid valve 6 is provided to proportionally control the inflation flow, so as to accurately reach the set pressure value, prevent overcharging and undercharging, and accurately obtain the SF6 volume and gas volume after processing the sensor data.

[0037] A SF6 inflation measuring method for a GIS device, the following steps:

[0038] S1, before inflation, the gas temperature T0 and the pressure P0 in the gas chamber are measured by the ambient temperature sensor and the ambient pressure sensor respectively, and the SF6 gas density p0 in the closed space before inflation is calculated by the Beattie-Bridgman gas state equation;

[0039] S2, during inflation, the gas temperature T p and the pipe gas temperature T i in the gas chamber are measured by the ambient temperature sensor and the pipe temperature sensor respectively, and the multi-stage fuzzy temperature control module adjusts the temperature of the pipe according to the difference AT i between the two before the gas is charged into the gas chamber;

[0040] S3, the instantaneous output flow q and the output time t are measured by the mass flow meter, the total flow Q is calculated by the cumulative flow integral algorithm, and the formula is used to calculate the supplementary SF6 gas volume AV.

[0041] S4, calculate the SF6 gas density p at 20℃ and standard atmospheric pressure by Beattie-Bridgman gas state equation t , multiply the SF6 gas density p t with the SF6 gas volume AV to calculate the supplementary SF6 gas mass Am;

[0042] S5, after the inflation is completed, according to the environmental temperature sensor and the environmental pressure sensor measurement data T1 and P1, calculate the SF6 gas density p1 in the gas chamber after the inflation by Beattie-Bridgman gas state equation;

[0043] S6, the effective volume V of the closed space is obtained by the formula ;

[0044] S7, multiply the SF6 gas density p1 of the closed space with the effective volume V of the closed space to calculate the SF6 gas volume m1 after the inflation.

[0045] In steps S1, S4 and S5, the formula of Beattie-Bridgman gas state equation is as follows:

[0046] P = (RTB-A) p2 + RTp

[0047] A = 73.882 x 10-5-5.132105 x 10-7p

[0048] B = 2.50695 x 10-3-2.12283 x 10-6p

[0049] R = 56.9502 x 10-5

[0050] Wherein, T is the gas temperature measured by the environmental temperature sensor, P is the pressure measured by the environmental pressure sensor, and p is the SF6 gas density.

[0051] The calculation accuracy of the cumulative flow is related to the accuracy of the final measurement result. In order to ensure the accurate measurement of the final data, a cumulative flow integral algorithm based on a single-chip microcomputer is used to calculate the flow. As shown in Figure 2 , all the instantaneous output flow data measured by the mass flowmeter are summarized to obtain a smooth straight line. According to the geometric meaning of definite integral, the cumulative flow in the time period [a, b] can be obtained by calculating the area of the curved graph surrounded by the curve q = q(t), the straight line t = a, t = b and the time axis t.

[0052] Insert several sub-points a = t 0< t1 < t2 < … t n-1 < t n= b, divide the interval [a, b] into n small intervals [t i -1, t i ], length The cumulative flow over the time length Δt i is obtained by calculating the area of the ith small curved trapezoid, and the area of the ith small curved trapezoid

[0053] By infinitely amplifying the instantaneous flow acquisition rate, n tends to infinity, and the total flow

[0054] The area of each small curved trapezoid can be calculated by using the infinitesimal acquisition time and the instantaneous flow acquired, and then the final cumulative flow data is obtained by sequentially accumulating.

[0055] According to the operation experience, the SF6 gas cylinder is used as the gas source for the inflation operation, and the gaseous SF6 generated after the phase change of the liquid SF6 in the gas cylinder has extremely low temperature. After the pipeline is filled into the gas chamber, the temperature thereof will always change to the ambient temperature. At the end of the inflation, the gas temperature in the gas chamber will be between the above two temperatures. Therefore, the temperature sensor installed on the inflation pipeline has a certain deviation from the gas temperature in the gas chamber at the end of the inflation, whether detecting the temperature in the pipeline or the ambient temperature, thereby affecting the measurement results of the gas amount and the effective volume of the SF6 gas in the gas chamber.

[0056] Compared with the traditional constant temperature control method, the fuzzy control technology does not need to pay attention to too many dynamic parameters. By using the pre-designed fuzzy language variables and control logic, the control parameters are adaptively set, the temperature is accurately controlled, and good robustness is achieved. Therefore, the three temperature control modules are connected in series in the pipeline, the temperature change in the pipeline is tracked in real time, and different fuzzy control logics are used to control the heat source temperature of each temperature control module, so that the temperature of the SF6 gas is accurately locked to the ambient temperature.

[0057] As shown in Figure 3 , the multi-stage fuzzy temperature control module includes three temperature control modules, three pipeline temperature sensors, and three temperature control modules are connected in series on the pipeline, and the three pipeline temperature sensors and the three temperature control modules are sequentially first pipeline temperature sensor 71, first temperature control module 81, second pipeline temperature sensor 72, second temperature control module 82, third pipeline temperature sensor 73 and third temperature control module 83.

[0058] The input of the first temperature control module is the difference ΔT p between the temperature T i1 measured by the ambient temperature sensor in the gas chamber and the gas temperature T i1 measured by the first pipeline temperature sensor in the pipeline, and the value range of the difference ΔT i1 is E1[0, 45], which is evenly divided into three small intervals: E11 [0,15), E 12 [15,30), E 13 [30,45], and E 11 E 12 E 13 Corresponding to heat source temperature T 11 T 12 T 13 , among which, T 11 <T 12 <T 13 ;

[0059] The input to the second temperature control module is the temperature T in the air chamber measured by the ambient temperature sensor. p The gas temperature T inside the pipe measured by the second pipe temperature sensor i2 The difference ΔT i2 The difference ΔT i2 The value range of is E2[-7.5, 7.5]. This range is divided into 3 smaller intervals: E 21 [-7.5,-1), E 22 [-1,1), E 23 [1,7.5], and E 21 E 22 E 23 Corresponding to heat source temperature T 21 T 22 T 23 , among which, T 21 <T 22 <T 23 ;

[0060] The input to the third temperature control module is the temperature T in the air chamber measured by the ambient temperature sensor. p The gas temperature T inside the pipe measured by the third pipe temperature sensor i3 The difference ΔT i3 The difference ΔT i3 The value range of is E3[-2,2]. This range is divided into 3 smaller intervals: E 31 [-2,-1), E 32 [-1,1), E 33 [1,2], and E 31 E 32 E 33 Corresponding to heat source temperature T 31 T 32 T 33 , among which, T 31 <T 32 <T 33 .

[0061] The heat source temperature parameters of the three temperature control modules are selected as shown in matrix Tij:

[0062]

[0063] wherein, T ij is in ℃, and the values of i and j are both {1, 2, 3}.

[0064] Real-time temperature locking effect verification

[0065] An experimental platform is built, and the gas inlet of the multi-stage fuzzy temperature control module as shown in Figure 3 is connected to an SF6 gas cylinder (4L) with a pressure reducing valve, and the gas outlet is connected to a gas storage tank (30L). The experimental platform is built in a thermostat to simulate different environmental temperatures, and the real-time temperature locking effect of the above multi-stage fuzzy temperature control module is verified. The experimental process is as follows:

[0066] a) The temperature of the thermostat is set to -10℃, and the environmental temperature sensor measures the temperature T p to be -10.2℃ after 2h of standing;

[0067] b) Start the multi-stage fuzzy temperature control module, adjust the pressure reducing valve to 0.7MPa (to ensure that the SF6 gas does not liquefy at the current environmental temperature), open the SF6 gas cylinder valve, and record the temperature T i4 measured by the temperature locking temperature sensor every 10s (as shown in Figure 3 , the temperature locking temperature sensor 9 is arranged behind the third temperature control module to measure the temperature of the SF6 gas after temperature locking), and stop the experiment after 3min;

[0068] c) Set the temperature of the thermostat to 0℃, 10℃, and 20℃, and the temperature Tp measured by the environmental temperature sensor to 0.3℃, 9.7℃, and 20.1℃, respectively, and repeat the above steps.

[0069] In the above experiment, the temperature variation curve of the SF6 gas after temperature locking by the multi-stage fuzzy temperature control module is shown in Figure 4 . As can be seen from Figure 4 , T i4 exhibits an obvious oscillation process in the initial stage, and tends to be stable at 110s-150s, and the deviation of T i4 and T p after stabilization is not more than ±1℃. The reason for the above oscillation phenomenon is that the heat source has not yet been warmed up to the set temperature in the initial stage, and the temperature locking effect is poor; but as the heat source gradually warms up to the set temperature, the temperature locking effect is enhanced, so that the SF6 gas after temperature locking is closer to the environmental temperature.

Claims

1. A method for measuring SF6 inflation in a GIS device, characterized in that, Includes the following steps: S1. Before inflation, the gas temperature T0 and pressure P0 in the gas chamber are measured by the ambient temperature sensor and ambient pressure sensor, respectively. The density ρ0 of SF6 gas in the sealed space before inflation is calculated by the Beattie-Bridgman gas state equation. S2. During the inflation process, the gas temperature T in the air chamber is measured by the ambient temperature sensor and the pipeline temperature sensor, respectively. p and the gas temperature T inside the pipeline i The multi-level fuzzy temperature control module uses the difference ∆T between the two values. i Temperature regulation of the pipeline is performed before the gas is introduced into the gas chamber; S3. Based on the instantaneous output flow rate q and output time t measured by the mass flow meter, the total flow rate Q is calculated by the cumulative flow integral algorithm, and then the supplementary SF6 gas volume ∆V is obtained by integral calculation. S4. Calculate the density ρ of SF6 gas at 20℃ and standard atmospheric pressure using the Beattie-Bridgman gas law. t SF6 gas density ρ t The mass of supplemented SF6 gas, ∆m, is calculated by multiplying it by the SF6 gas volume ∆V. S5. After inflation is completed, the density ρ1 of SF6 gas in the gas chamber after inflation is calculated using the Beattie-Bridgman gas state equation based on the measured data T1 and P1 from the ambient temperature sensor and ambient pressure sensor. S6, the effective volume V of the enclosed space is obtained through the formula... get; S7. Multiply the SF6 gas density ρ1 in the closed space and the effective volume V of the closed space to calculate the SF6 gas volume m1 after inflation. In step 2, the multi-level fuzzy temperature control module includes three temperature control modules, three pipe temperature sensors, and three temperature control modules connected in series and interleaved on the pipe. The three pipe temperature sensors and three temperature control modules are, in order, the first pipe temperature sensor, the first temperature control module, the second pipe temperature sensor, the second temperature control module, the third pipe temperature sensor, and the third temperature control module. The input of the first temperature control module is the temperature T in the air chamber measured by the ambient temperature sensor. p The gas temperature T inside the pipe measured by the first pipe temperature sensor i1 The difference ∆T i1 The difference ∆T i1 The value range of is E1[0,45]. This range is divided into 3 smaller intervals: E 11 [0,15), E 12 [15,30), E 13 [30,45], and E 11 E 12 E 13 Corresponding to heat source temperature T 11 T 12 T 13 , among which, T 11 <T 12 <T 13 ; The input to the second temperature control module is the temperature T in the air chamber measured by the ambient temperature sensor. p The gas temperature T inside the pipe measured by the second pipe temperature sensor i2 The difference ∆T i2 The difference ∆T i2 The value range of is E2[-7.5, 7.5]. This range is divided into 3 smaller intervals: E 21 [-7.5,-1), E 22 [-1,1), E 23 [1,7.5], and E 21 E 22 E 23 Corresponding to heat source temperature T 21 T 22 T 23 , among which, T 21 <T 22 <T 23 ; The input to the third temperature control module is the temperature T in the air chamber measured by the ambient temperature sensor. p The gas temperature T inside the pipe measured by the third pipe temperature sensor i3 The difference ∆T i3 The difference ∆T i3 The value range of is E3[-2,2]. This range is divided into 3 smaller intervals: E 31 [-2,-1), E 32 [-1,1), E 33 [1,2], and E 31 E 32 E 33 Corresponding to heat source temperature T 31 T 32 T 33 , among which, T 31 <T 32 <T 33 .

2. The SF6 inflation measurement method for GIS equipment as described in claim 1, characterized in that, In steps S1, S4, and S5, the Beattie-Bridgman gas law is as follows: ； Where T is the gas temperature measured by the ambient temperature sensor, P is the pressure measured by the ambient pressure sensor, and ρ is the SF6 gas density.

3. The SF6 inflation measurement method for GIS equipment as described in claim 1, characterized in that, The heat source temperature parameters for the three temperature control modules are selected as shown in matrix Tij: Among them, T ij The unit is ℃, and the values ​​of i and j are both {1,2,3}.

4. The SF6 inflation measurement method for GIS equipment as described in claim 1, characterized in that: In step 3, all instantaneous output flow data measured by the mass flow meter are summarized into a smooth straight line. Based on the geometric meaning of definite integral, the cumulative flow in the time period [a,b] can be obtained by calculating the area of ​​the curvilinear figure enclosed by the curve q=q(t), the straight lines t=a, t=b, and the time axis t.

5. The SF6 inflation measurement method for GIS equipment as described in claim 4, characterized in that: Insert several time points a=t within the time interval [a,b]. 0< t1 <t2<…t n-1 <t n =b, divide the interval [a,b] into n equal subintervals [t] i -1,t i ],length Time length Δt i The cumulative flow is obtained by calculating the area of ​​the i-th small curvilinear trapezoid. ; If the instantaneous flow rate is infinitely amplified, then n approaches infinity, and the total flow... .

6. The SF6 inflation measurement method for GIS equipment as described in claim 5, characterized in that: The supplementary SF6 gas volume ∆V is obtained through the formula get.

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