An environmental-friendly mixed gas switch post-arc recovery performance evaluation method and system

Abstract

The application discloses an environmental protection mixed gas switch post-arc recovery performance evaluation method and system. The method comprises the following steps: detecting the arc voltage, arc current, gas pressure and temperature in the arc chamber generated in the breaking test, and calculating the arc conductance and its rate of change with time; substituting the arc voltage, arc current, arc conductance and its rate of change with time into an arc model to calculate the post-arc current after the arc current zero-crossing, and judging whether the post-arc thermal recovery performance meets the breaking requirement based on the post-arc current; if the breaking requirement is met, determining the net ionization coefficient of the environmental protection mixed gas based on the gas pressure and temperature in the arc chamber, and obtaining the critical discharge field strength based on the net ionization coefficient; applying the system operating voltage on the switch equipment, calculating the electric field distribution in the arc chamber, comparing the critical discharge field strength with the electric field distribution, and determining whether the post-arc electric recovery performance of the environmental protection mixed gas meets the breaking requirement.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly gas-insulated power transmission and distribution equipment technology, and more specifically, to a method and system for evaluating the post-arc recovery performance of environmentally friendly mixed gas switches. Background Technology

[0002] Sulfur hexafluoride (SF6) gas is widely used in electrical equipment as an excellent insulating and arc-quenching medium. However, SF6 has a greenhouse effect 24,300 times that of CO2 and a lifespan in the atmosphere of up to 3,200 years, posing a significant adverse impact on the environment. Domestic and international research shows that environmentally friendly gases such as perfluoroisobutyronitrile (C4F7N) and trifluoromethanesulfonyl fluoride (CF3SO2F), when mixed with CO2, O2, and N2, exhibit high insulation strength and low greenhouse effect. These are considered superior environmentally friendly alternatives to SF6 and are gradually being implemented in engineering applications for insulation replacement in switchgear such as GIS, GIL, and ring main units.

[0003] However, there is a lack of research and public reports on the arc-extinguishing performance and high-capacity breaking technology of environmentally friendly mixed gases, leaving considerable uncertainty. Because environmentally friendly gases have a lower greenhouse effect and degrade more rapidly in the atmosphere, their stability and recombination properties after ionization are limited. Summary of the Invention

[0004] This invention provides a method and system for evaluating the post-arc recovery performance of environmentally friendly mixed gas switches, addressing the lack of research and public reports on the arc-extinguishing performance and high-capacity breaking technology of environmentally friendly mixed gases, which still presents significant uncertainties. Due to the low greenhouse effect of environmentally friendly gases, they degrade rapidly in the atmosphere, limiting their stability and recombination properties after ionization.

[0005] According to a first aspect of the present invention, a method for evaluating the post-arc recovery performance of an environmentally friendly mixed gas switch is provided, comprising:

[0006] The arc voltage, arc current, gas pressure and temperature in the arc extinguishing chamber generated by the interruption test conditions are detected, and the arc conductance and its rate of change with respect to time are calculated.

[0007] Substituting the arc voltage, arc current, arc conductance, and their rate of change with respect to time into the arc model, the post-arc current after the arc current crosses zero is calculated. Based on the post-arc current, it is determined whether the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements.

[0008] If the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the net ionization coefficient of the environmentally friendly mixed gas is determined based on the gas pressure and temperature in the arc extinguishing chamber, and the critical discharge field strength is obtained based on the net ionization coefficient.

[0009] Apply the system operating voltage to the switching equipment, calculate the electric field distribution in the arc-extinguishing chamber, compare the critical discharge field strength with the electric field distribution, and determine whether the post-arc electric recovery performance of the environmentally friendly mixed gas meets the breaking requirements.

[0010] Optionally, the arc voltage, arc current, gas pressure and temperature inside the arc-extinguishing chamber generated by the breaking test are detected, and the arc conductance and its rate of change with respect to time are calculated, including:

[0011] The environmentally friendly mixed gas is filled into a switchgear with an arc-generating function. An arc-generating test is performed on the switchgear to determine the test current. The gas pressure and the volume ratio of the environmentally friendly insulating gas are changed. The changes in arc voltage u, arc current i, gas pressure P and temperature T in the arc-extinguishing chamber are detected under each test condition. The arc conductivity g = i / u and its rate of change with respect to time dg / dt are calculated.

[0012] Optionally, the arc voltage, arc current, arc conductance, and their rate of change with respect to time are substituted into the arc model to calculate the post-arc current after the arc current crosses zero. Based on the post-arc current, it is determined whether the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, including:

[0013] Substituting the experimentally detected arc voltage u, arc current i, and calculated arc conductance g and its rate of change with respect to time dg / dt into the Mayr arc model, the expression is as follows:

[0014]

[0015] In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into formula (1) to calculate θ and Q.

[0016] By applying recovery voltages u with different rise rates and substituting them into the arc model, the post-arc current i after the arc current crosses zero can be calculated.

[0017] If the instantaneous value of the post-arc current i drops to a value greater than the predetermined value within a predetermined time after crossing zero, change the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas, and re-perform the opening and closing tests on the switchgear.

[0018] If the instantaneous value of the post-arc current i drops to no more than a predetermined value within a predetermined time after crossing zero, it is determined that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and the corresponding recovery voltage rise rate value is obtained.

[0019] Optionally, if the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the net ionization coefficient of the environmentally friendly mixed gas is determined based on the gas pressure and temperature in the arc extinguishing chamber, and the critical discharge field strength is obtained based on the net ionization coefficient, including:

[0020] If the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the pressure P at this time is obtained based on the gas pressure and temperature in the arc-extinguishing chamber. e and temperature T e Determine the net ionization coefficient of the environmentally friendly mixed gas. The expression is:

[0021]

[0022] In the formula, N is the number of particles, k is the volume ratio of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) to zero, the critical reduced discharge field strength (E / N) is calculated. c ,

[0023] Ideal gas law, expression:

[0024] P e V = NRT e (3)

[0025] In the formula, V is the volume of the arc-extinguishing chamber, R is a constant of 8.31 J / (mol·K), and the combined pressure P e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

[0026] Optionally, applying a system operating voltage to the switching equipment, calculating the electric field distribution inside the arc-extinguishing chamber, and comparing the critical discharge field strength with that based on the electric field distribution to determine whether the post-arc electric recovery performance of the environmentally friendly mixed gas meets the breaking requirements, includes: applying a system operating voltage to the switching equipment and calculating the electric field distribution inside the arc-extinguishing chamber;

[0027] If the electric field distribution at every point in the arc-extinguishing chamber is not less than the critical discharge field strength, the post-arc electric recovery performance of the environmentally friendly mixed gas is determined to meet the breaking requirements.

[0028] Otherwise, improve the structural design of the parts of the arc-extinguishing chamber where the electric field distribution is less than the critical discharge field strength, so that the hot environmentally friendly mixed gas has the electrical recovery performance to meet the breaking requirements.

[0029] According to another aspect of the present invention, an environmentally friendly mixed gas switch post-arc recovery performance evaluation system is also provided, comprising:

[0030] The test parameter detection module is used to detect the arc voltage, arc current, gas pressure and temperature in the arc extinguishing chamber generated by the breaking test, and to calculate the arc conductance and its rate of change with respect to time.

[0031] The heat recovery performance determination module is used to substitute the arc voltage, arc current, arc conductance and their rate of change with respect to time into the arc model, calculate the post-arc current after the arc current crosses zero, and determine whether the post-arc heat recovery performance of the environmentally friendly mixed gas meets the breaking requirements based on the post-arc current.

[0032] The critical discharge field strength module is used to determine the net ionization coefficient of the environmentally friendly mixed gas based on the gas pressure and temperature in the arc extinguishing chamber if the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and to obtain the critical discharge field strength based on the net ionization coefficient.

[0033] The electrical recovery performance assessment module is used to apply the system operating voltage to the switching equipment, calculate the electric field distribution in the arc-extinguishing chamber, compare the critical discharge field strength with the electric field distribution, and determine whether the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the interruption requirements.

[0034] Optionally, the test parameter detection module includes:

[0035] The test parameter determination submodule is used to fill the environmentally friendly mixed gas into a switchgear with an arc-generating function, conduct an arc-breaking test on the switchgear, determine the test current, change the gas pressure and the volume ratio of the environmentally friendly insulating gas, detect the changes in arc voltage u, arc current i, gas pressure P and temperature T in the arc-extinguishing chamber under each test condition, and calculate the arc conductivity g = i / u and its rate of change with respect to time dg / dt.

[0036] Optionally, the module for determining thermal recovery performance includes:

[0037] The submodule for obtaining the arc time constant and energy dissipation coefficient is used to substitute the experimentally detected arc voltage u, arc current i, and calculated arc conductance g and its rate of change with respect to time dg / dt into the Mayr arc model, as shown in the following expression:

[0038]

[0039] In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into formula (1) to calculate θ and Q.

[0040] The post-arc current calculation submodule is used to apply recovery voltages u with different rise rates, substitute them into the arc model, and calculate the post-arc current i after the arc current crosses zero.

[0041] The retest submodule is used to retest the switching equipment if the instantaneous value of the post-arc current i drops to a value greater than a predetermined value within a predetermined time after zero crossing, by changing the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas.

[0042] The submodule for obtaining the recovery voltage rise rate is used to determine that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the interruption requirements if the instantaneous value of the post-arc current i drops to no more than a predetermined value within a predetermined time after crossing zero, and to obtain the corresponding recovery voltage rise rate value.

[0043] Optionally, the critical discharge field strength module is obtained, including:

[0044] The critical discharge field hadron module is used to calculate the pressure P at the moment the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, based on the gas pressure and temperature inside the arc-extinguishing chamber. e and temperature T e Determine the net ionization coefficient of the environmentally friendly mixed gas. The expression is:

[0045]

[0046] In the formula, N is the number of particles, k is the volume ratio of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) to zero, the critical reduced discharge field strength (E / N) is calculated. c ,

[0047] Ideal gas law, expression:

[0048] P e V = NRT e (3)

[0049] In the formula, V is the volume of the arc-extinguishing chamber, R is a constant of 8.31 J / (mol·K), and the combined pressure P e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

[0050] Optionally, the module for determining electrical recovery performance includes:

[0051] The electric field distribution calculation submodule is used to apply the system operating voltage to the switching equipment and calculate the electric field distribution inside the arc-extinguishing chamber;

[0052] The electrical recovery performance meets the breaking requirements submodule, which is used to determine whether the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the breaking requirements if the electric field distribution at each point in the arc extinguishing chamber is not less than the critical discharge field strength.

[0053] Improve the structural design submodule to improve the structural design of the parts of the arc extinguishing chamber where the electric field distribution is less than the critical discharge field strength, so that the hot environmentally friendly mixed gas has the electrical recovery performance that meets the breaking requirements.

[0054] Therefore, by filling the environmentally friendly mixed gas into a switchgear with arc-generating breaking function and conducting experiments, the post-arc current after the switchgear breaks was calculated, and the thermal recovery performance of the environmentally friendly mixed gas was determined based on whether it met the requirements. Based on this, the critical electric field distribution in the arc-extinguishing chamber of the switchgear was calculated to determine whether the gas would undergo electrical breakdown under the action of the recovery voltage, and the electrical recovery performance of the environmentally friendly mixed gas was analyzed. Thus, the post-arc recovery performance of the environmentally friendly mixed gas switchgear was understood, and an optimized design scheme for the gas pressure and volume ratio of the mixed gas with breaking capability, as well as the arc-extinguishing chamber structure, was proposed, providing a basis and guidance for the research and development of environmentally friendly gas switchgear. Attached Figure Description

[0055] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0056] Figure 1 This is a flowchart illustrating an environmentally friendly mixed gas switch post-arc recovery performance evaluation method as described in this embodiment.

[0057] Figure 2 This is a schematic diagram of an environmentally friendly mixed gas switch post-arc recovery performance evaluation system described in this embodiment. Detailed Implementation

[0058] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0059] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0060] According to a first aspect of the present invention, an environmentally friendly mixed gas switch post-arc recovery performance evaluation method 100 is provided, with reference to... Figure 1 As shown, the method 100 includes:

[0061] S101: Detect the arc voltage, arc current, gas pressure and temperature in the arc extinguishing chamber generated by the interruption test conditions, and calculate the arc conductance and its rate of change with respect to time.

[0062] S102: Substitute the arc voltage, arc current, arc conductance and their rate of change with respect to time into the arc model to calculate the post-arc current after the arc current crosses zero, and determine whether the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements based on the post-arc current.

[0063] S103: If the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the net ionization coefficient of the environmentally friendly mixed gas is determined based on the gas pressure and temperature in the arc extinguishing chamber, and the critical discharge field strength is obtained based on the net ionization coefficient.

[0064] S104: Apply the system operating voltage to the switching equipment, calculate the electric field distribution in the arc-extinguishing chamber, compare the critical discharge field strength with the electric field distribution, and determine whether the post-arc electric recovery performance of the environmentally friendly mixed gas meets the interruption requirements.

[0065] Specifically, the environmentally friendly mixed gas in switchgear ionizes during the switching process, generating a large amount of high-temperature plasma, mainly composed of electrons, various ions, and neutral atoms. After the current crosses zero, the arc temperature in the arc-extinguishing chamber drops sharply. Most of the particles that have cooled down recombine, rapidly entering the thermal and electrical recovery stages, allowing the gas to return to its insulating state with high insulation strength, meeting the voltage withstand requirements of the power system during normal operation. Therefore, proposing a method and device for evaluating the post-arc recovery performance of environmentally friendly mixed gas switches, and effectively assessing the gas's post-arc recovery performance, is crucial to ensuring the normal switching operation of the equipment.

[0066] It consists of a binary or ternary environmentally friendly mixed gas composed of environmentally friendly insulating gases such as perfluoroisobutyronitrile (C4F7N) and trifluoromethanesulfonyl fluoride (CF3SO2F) and buffer gases such as CO2, O2, and N2, with a gas pressure of 0.6 to 0.8 MPa and the volume percentage of environmentally friendly insulating gas k not exceeding 15%.

[0067] An environmentally friendly mixed gas is filled into switchgear such as circuit breakers that have the function of generating an electric arc during interruption. The switching equipment is subjected to interruption and closing tests in accordance with GB1984-2014 "High Voltage AC Circuit Breakers". The test current is 1 to 10 kA. The gas pressure and the volume ratio of environmentally friendly insulating gas are changed. The waveforms of arc voltage u and arc current i generated under each test condition are detected, as well as the changes in gas pressure P and temperature T in the arc extinguishing chamber. The arc conductivity g = i / u and its rate of change with respect to time dg / dt are calculated.

[0068] Using the experimentally detected u and i, and the calculated g and dg / dt, and substituting them into the Mayr arc model, the expression is as follows:

[0069]

[0070] In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into equation (1) to calculate θ and Q.

[0071] Referring to the transient recovery voltage requirements characterized by the four-parameter method in GB 1984-2014 "High Voltage AC Circuit Breakers", recovery voltages u with different rise rates RRRV are applied and substituted into equation (1) to calculate the post-arc current i after the arc current crosses zero. If the instantaneous value of current i drops to no more than 1mA within 20μs after crossing zero, it indicates that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and the corresponding recovery voltage rise rate RRRV value is obtained.

[0072] If the post-arc current i does not meet the requirements, it is necessary to change the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas, and repeat steps (2) to (4).

[0073] Based on the fact that environmentally friendly mixed gases possess post-arc thermal recovery performance that meets the interruption requirements, and utilizing the detected gas pressure P and temperature T distribution within the arc-extinguishing chamber, the pressure P at which the gas thermal recovery within the arc-extinguishing chamber ends is obtained when the post-arc current drops to less than 1 mA. e and temperature T e .

[0074] Net ionization coefficient of environmentally friendly mixed gases The expression is:

[0075]

[0076] In the formula, N is the number of particles, k is the volume percentage of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) to zero, the critical reduced discharge field strength (E / N) is calculated. c .

[0077] Using the ideal gas law, the expression is:

[0078] P e V = NRT e (3)

[0079] In the formula, V is the volume of the arc-extinguishing chamber, and R is a constant of 8.31 J / (mol·K). Combined with the pressure P... e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

[0080] Apply the system operating voltage to the switching equipment and calculate the electric field distribution E inside the arc-extinguishing chamber. a If E at each point in the arc-extinguishing chamber a All are not less than E c This indicates that the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the breaking requirements; otherwise, the E in the arc-extinguishing chamber needs to be improved. a Less than E c The structural design of the components enables the hot environmentally friendly mixed gas to have electrical recovery performance that meets the requirements for interruption.

[0081] Therefore, by filling the environmentally friendly mixed gas into a switchgear with arc-generating breaking function and conducting experiments, the post-arc current after the switchgear breaks was calculated, and the thermal recovery performance of the environmentally friendly mixed gas was determined based on whether it met the requirements. Based on this, the critical electric field distribution in the arc-extinguishing chamber of the switchgear was calculated to determine whether the gas would undergo electrical breakdown under the action of the recovery voltage, and the electrical recovery performance of the environmentally friendly mixed gas was analyzed. Thus, the post-arc recovery performance of the environmentally friendly mixed gas switchgear was understood, and an optimized design scheme for the gas pressure and volume ratio of the mixed gas with breaking capability, as well as the arc-extinguishing chamber structure, was proposed, providing a basis and guidance for the research and development of environmentally friendly gas switchgear.

[0082] Optionally, the arc voltage, arc current, gas pressure and temperature inside the arc-extinguishing chamber generated by the breaking test are detected, and the arc conductance and its rate of change with respect to time are calculated, including:

[0083] The environmentally friendly mixed gas is filled into a switchgear with an arc-generating function. An arc-generating test is performed on the switchgear to determine the test current. The gas pressure and the volume ratio of the environmentally friendly insulating gas are changed. The changes in arc voltage u, arc current i, gas pressure P and temperature T in the arc-extinguishing chamber are detected under each test condition. The arc conductivity g = i / u and its rate of change with respect to time dg / dt are calculated.

[0084] Optionally, the arc voltage, arc current, arc conductance, and their rate of change with respect to time are substituted into the arc model to calculate the post-arc current after the arc current crosses zero. Based on the post-arc current, it is determined whether the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, including:

[0085] Substituting the experimentally detected arc voltage u, arc current i, and calculated arc conductance g and its rate of change with respect to time dg / dt into the Mayr arc model, the expression is as follows:

[0086]

[0087] In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into formula (1) to calculate θ and Q.

[0088] By applying recovery voltages u with different rise rates and substituting them into the arc model, the post-arc current i after the arc current crosses zero can be calculated.

[0089] If the instantaneous value of the post-arc current i drops to a value greater than the predetermined value within a predetermined time after crossing zero, change the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas, and re-perform the opening and closing tests on the switchgear.

[0090] If the instantaneous value of the post-arc current i drops to no more than a predetermined value within a predetermined time after crossing zero, it is determined that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and the corresponding recovery voltage rise rate value is obtained.

[0091] Optionally, if the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the net ionization coefficient of the environmentally friendly mixed gas is determined based on the gas pressure and temperature in the arc extinguishing chamber, and the critical discharge field strength is obtained based on the net ionization coefficient, including:

[0092] If the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the pressure P at this time is obtained based on the gas pressure and temperature in the arc-extinguishing chamber. e and temperature T e Determine the net ionization coefficient of the environmentally friendly mixed gas. The expression is:

[0093]

[0094] In the formula, N is the number of particles, k is the volume ratio of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) to zero, the critical reduced discharge field strength (E / N) is calculated. c ,

[0095] Ideal gas law, expression:

[0096] P e V = NRT e (3)

[0097] In the formula, V is the volume of the arc-extinguishing chamber, R is a constant of 8.31 J / (mol·K), and the combined pressure P e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

[0098] Optionally, applying a system operating voltage to the switching equipment, calculating the electric field distribution inside the arc-extinguishing chamber, and comparing the critical discharge field strength with that based on the electric field distribution to determine whether the post-arc electric recovery performance of the environmentally friendly mixed gas meets the breaking requirements, includes: applying a system operating voltage to the switching equipment and calculating the electric field distribution inside the arc-extinguishing chamber;

[0099] If the electric field distribution at every point in the arc-extinguishing chamber is not less than the critical discharge field strength, the post-arc electric recovery performance of the environmentally friendly mixed gas is determined to meet the breaking requirements.

[0100] Otherwise, improve the structural design of the parts of the arc-extinguishing chamber where the electric field distribution is less than the critical discharge field strength, so that the hot environmentally friendly mixed gas has the electrical recovery performance to meet the breaking requirements.

[0101] Therefore, by filling the environmentally friendly mixed gas into a switchgear with arc-generating breaking function and conducting experiments, the post-arc current after the switchgear breaks was calculated, and the thermal recovery performance of the environmentally friendly mixed gas was determined based on whether it met the requirements. Based on this, the critical electric field distribution in the arc-extinguishing chamber of the switchgear was calculated to determine whether the gas would undergo electrical breakdown under the action of the recovery voltage, and the electrical recovery performance of the environmentally friendly mixed gas was analyzed. Thus, the post-arc recovery performance of the environmentally friendly mixed gas switchgear was understood, and an optimized design scheme for the gas pressure and volume ratio of the mixed gas with breaking capability, as well as the arc-extinguishing chamber structure, was proposed, providing a basis and guidance for the research and development of environmentally friendly gas switchgear.

[0102] According to another aspect of the present invention, an environmentally friendly mixed gas switch post-arc recovery performance evaluation system 200 is also provided, with reference to... Figure 2 As shown, the system 200 includes:

[0103] The test parameter detection module 210 is used to detect the arc voltage, arc current, gas pressure and temperature in the arc extinguishing chamber generated by the breaking test, and to calculate the arc conductance and its rate of change with respect to time.

[0104] The heat recovery performance judgment module 220 is used to substitute the arc voltage, arc current, arc conductance and their rate of change with respect to time into the arc model, calculate the post-arc current after the arc current crosses zero, and judge whether the post-arc heat recovery performance of the environmentally friendly mixed gas meets the breaking requirements based on the post-arc current.

[0105] The critical discharge field strength module 230 is used to determine the net ionization coefficient of the environmentally friendly mixed gas based on the gas pressure and temperature in the arc extinguishing chamber if the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and to obtain the critical discharge field strength based on the net ionization coefficient.

[0106] The electrical recovery performance determination module 240 is used to apply the system operating voltage to the switching equipment, calculate the electric field distribution in the arc extinguishing chamber, compare the critical discharge field strength with the electric field distribution, and determine whether the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the interruption requirements.

[0107] Optionally, the test parameter detection module includes:

[0108] The test parameter determination submodule is used to fill the environmentally friendly mixed gas into a switchgear with an arc-generating function, conduct an arc-breaking test on the switchgear, determine the test current, change the gas pressure and the volume ratio of the environmentally friendly insulating gas, detect the changes in arc voltage u, arc current i, gas pressure P and temperature T in the arc-extinguishing chamber under each test condition, and calculate the arc conductivity g = i / u and its rate of change with respect to time dg / dt.

[0109] Optionally, the module for determining thermal recovery performance includes:

[0110] The submodule for obtaining the arc time constant and energy dissipation coefficient is used to substitute the experimentally detected arc voltage u, arc current i, and calculated arc conductance g and its rate of change with respect to time dg / dt into the Mayr arc model, as shown in the following expression:

[0111]

[0112] In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into formula (1) to calculate θ and Q.

[0113] The post-arc current calculation submodule is used to apply recovery voltages u with different rise rates, substitute them into the arc model, and calculate the post-arc current i after the arc current crosses zero.

[0114] The retest submodule is used to retest the switching equipment if the instantaneous value of the post-arc current i drops to a value greater than a predetermined value within a predetermined time after zero crossing, by changing the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas.

[0115] The submodule for obtaining the recovery voltage rise rate is used to determine that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the interruption requirements if the instantaneous value of the post-arc current i drops to no more than a predetermined value within a predetermined time after crossing zero, and to obtain the corresponding recovery voltage rise rate value.

[0116] Optionally, the critical discharge field strength module is obtained, including:

[0117] The critical discharge field hadron module is used to calculate the pressure P at the moment the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, based on the gas pressure and temperature inside the arc-extinguishing chamber. e and temperature T e Determine the net ionization coefficient of the environmentally friendly mixed gas. The expression is:

[0118]

[0119] In the formula, N is the number of particles, k is the volume ratio of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) to zero, the critical reduced discharge field strength (E / N) is calculated. c ,

[0120] Ideal gas law, expression:

[0121] P e V = NRT e (3)

[0122] In the formula, V is the volume of the arc-extinguishing chamber, R is a constant of 8.31 J / (mol·K), and the combined pressure P e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

[0123] Optionally, the module for determining electrical recovery performance includes:

[0124] The electric field distribution calculation submodule is used to apply the system operating voltage to the switching equipment and calculate the electric field distribution inside the arc-extinguishing chamber;

[0125] The electrical recovery performance meets the breaking requirements submodule, which is used to determine whether the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the breaking requirements if the electric field distribution at each point in the arc extinguishing chamber is not less than the critical discharge field strength.

[0126] Improve the structural design submodule to improve the structural design of the parts of the arc extinguishing chamber where the electric field distribution is less than the critical discharge field strength, so that the hot environmentally friendly mixed gas has the electrical recovery performance that meets the breaking requirements.

[0127] The environmentally friendly mixed gas switch post-arc recovery performance evaluation system 200 of this invention corresponds to the environmentally friendly mixed gas switch post-arc recovery performance evaluation method 100 of another embodiment of this invention, and will not be described again here.

[0128] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0129] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0130] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0131] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0132] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0133] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for evaluating the post-arc recovery performance of an environmentally friendly mixed gas switch, characterized in that, include: The arc voltage, arc current, gas pressure and temperature in the arc extinguishing chamber generated by the breaking test are detected, and the arc conductivity and its rate of change with respect to time are calculated. Substituting the arc voltage, arc current, arc conductance, and their rate of change with respect to time into the arc model, the post-arc current after the arc current crosses zero is calculated. Based on the post-arc current, it is determined whether the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements. If the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the net ionization coefficient of the environmentally friendly mixed gas is determined based on the gas pressure and temperature in the arc extinguishing chamber, and the critical discharge field strength is obtained based on the net ionization coefficient. Apply the system operating voltage to the switching equipment, calculate the electric field distribution in the arc-extinguishing chamber, compare the critical discharge field strength with the electric field distribution, and determine whether the post-arc electric recovery performance of the environmentally friendly mixed gas meets the breaking requirements.

2. The method according to claim 1, characterized in that, The arc voltage, arc current, gas pressure and temperature inside the arc-extinguishing chamber are measured during the interruption test, and the arc conductance and its rate of change with respect to time are calculated, including: The environmentally friendly mixed gas is filled into a switchgear with an arc-generating function. An arc-generating test is performed on the switchgear to determine the test current. The gas pressure and the volume ratio of the environmentally friendly insulating gas are changed. The changes in arc voltage u, arc current i, gas pressure P and temperature T in the arc-extinguishing chamber are detected under each test condition. The arc conductivity g = i / u and its rate of change with respect to time dg / dt are calculated.

3. The method according to claim 1, characterized in that, Substituting the arc voltage, arc current, arc conductance, and their rate of change with respect to time into the arc model, the post-arc current after the arc current crosses zero is calculated. Based on the post-arc current, it is determined whether the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, including: Substituting the experimentally detected arc voltage u, arc current i, and calculated arc conductance g and its rate of change with respect to time dg / dt into the Mayr arc model, the expression is as follows: In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into formula (1) to calculate θ and Q. By applying recovery voltages u with different rise rates and substituting them into the arc model, the post-arc current i after the arc current crosses zero can be calculated. If the instantaneous value of the post-arc current i drops to a value greater than the predetermined value within a predetermined time after crossing zero, change the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas, and re-perform the opening and closing tests on the switchgear. If the instantaneous value of the post-arc current i drops to no more than a predetermined value within a predetermined time after crossing zero, it is determined that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and the corresponding recovery voltage rise rate value is obtained.

4. The method according to claim 1, characterized in that, If the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the net ionization coefficient of the environmentally friendly mixed gas is determined based on the gas pressure and temperature inside the arc-extinguishing chamber. The critical discharge field strength is then obtained based on the net ionization coefficient, including: if the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, the pressure P at this time is obtained based on the gas pressure and temperature inside the arc-extinguishing chamber. e and temperature T e Determine the net ionization coefficient of the environmentally friendly mixed gas. The expression is: In the formula, N is the number of particles, k is the volume ratio of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) equal to zero, the critical reduced discharge field strength (E / N)c is calculated. Ideal gas law, expression: P e V=NRT e (3) In the formula, V is the volume of the arc-extinguishing chamber, R is a constant of 8.31 J / (mol·K), and the combined pressure P e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

5. The method according to claim 1, characterized in that, Applying the system operating voltage to the switching equipment, calculating the electric field distribution within the arc-extinguishing chamber, and comparing the critical discharge field strength with the electric field distribution to determine whether the post-arc electric recovery performance of the environmentally friendly mixed gas meets the breaking requirements, including: Apply the system operating voltage to the switching equipment and calculate the electric field distribution inside the arc-extinguishing chamber; If the electric field distribution at every point in the arc-extinguishing chamber is not less than the critical discharge field strength, the post-arc electric recovery performance of the environmentally friendly mixed gas is determined to meet the breaking requirements. Otherwise, improve the structural design of the parts of the arc-extinguishing chamber where the electric field distribution is less than the critical discharge field strength, so that the hot environmentally friendly mixed gas has the electrical recovery performance to meet the breaking requirements.

6. An environmentally friendly mixed gas switch post-arc recovery performance evaluation system, characterized in that, include: The test parameter detection module is used to detect the arc voltage, arc current, gas pressure and temperature in the arc extinguishing chamber generated by the breaking test, and to calculate the arc conductance and its rate of change with respect to time. The heat recovery performance determination module is used to substitute the arc voltage, arc current, arc conductance and their rate of change with respect to time into the arc model, calculate the post-arc current after the arc current crosses zero, and determine whether the post-arc heat recovery performance of the environmentally friendly mixed gas meets the breaking requirements based on the post-arc current. The critical discharge field strength module is used to determine the net ionization coefficient of the environmentally friendly mixed gas based on the gas pressure and temperature in the arc extinguishing chamber if the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, and to obtain the critical discharge field strength based on the net ionization coefficient. The electrical recovery performance assessment module is used to apply the system operating voltage to the switching equipment, calculate the electric field distribution in the arc-extinguishing chamber, compare the critical discharge field strength with the electric field distribution, and determine whether the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the interruption requirements.

7. The system according to claim 6, characterized in that, The test parameter detection module includes: The test parameter determination submodule is used to fill the environmentally friendly mixed gas into a switchgear with an arc-generating function, conduct an arc-breaking test on the switchgear, determine the test current, change the gas pressure and the volume ratio of the environmentally friendly insulating gas, detect the changes in arc voltage u, arc current i, gas pressure P and temperature T in the arc-extinguishing chamber under each test condition, and calculate the arc conductivity g = i / u and its rate of change with respect to time dg / dt.

8. The system according to claim 6, characterized in that, The module for determining thermal recovery performance includes: The submodule for obtaining the arc time constant and energy dissipation coefficient is used to substitute the experimentally detected arc voltage u, arc current i, and calculated arc conductance g and its rate of change with respect to time dg / dt into the Mayr arc model, as shown in the following expression: In the formula, θ and Q are the arc time constant and energy dissipation coefficient, respectively. The arc voltage u and arc current i waveforms within 50 μs before the arc current crosses zero are fitted, and the corresponding g and dg / dt are substituted into formula (1) to calculate θ and Q. The post-arc current calculation submodule is used to apply recovery voltages u with different rise rates, substitute them into the arc model, and calculate the post-arc current i after the arc current crosses zero. The retest submodule is used to retest the switching equipment if the instantaneous value of the post-arc current i drops to a value greater than a predetermined value within a predetermined time after zero crossing, by changing the gas pressure of the environmentally friendly mixed gas or the volume ratio of the environmentally friendly insulating gas. The submodule for obtaining the recovery voltage rise rate is used to determine that the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the interruption requirements if the instantaneous value of the post-arc current i drops to no more than a predetermined value within a predetermined time after crossing zero, and to obtain the corresponding recovery voltage rise rate value.

9. The system according to claim 6, characterized in that, The module for obtaining the critical discharge field strength includes: The critical discharge field hadron module is used to calculate the pressure P at the moment the post-arc thermal recovery performance of the environmentally friendly mixed gas meets the breaking requirements, based on the gas pressure and temperature inside the arc-extinguishing chamber. e and temperature T e Determine the net ionization coefficient of the environmentally friendly mixed gas. The expression is: In the formula, N is the number of particles, k is the volume ratio of the environmentally friendly insulating gas, and E / N is the reduced discharge field strength (Td). Setting equation (2) equal to zero, the critical reduced discharge field strength (E / N)c is calculated. Ideal gas law, expression: P e V=NRT e (3) In the formula, V is the volume of the arc-extinguishing chamber, R is a constant of 8.31 J / (mol·K), and the combined pressure P e and temperature T e N is calculated using equation (3), and then substituted into equation (2) to obtain the critical discharge field strength E. c .

10. The system according to claim 6, characterized in that, The module for determining electrical recovery performance includes: The electric field distribution calculation submodule is used to apply the system operating voltage to the switching equipment and calculate the electric field distribution inside the arc-extinguishing chamber; The electrical recovery performance meets the breaking requirements submodule, which is used to determine whether the post-arc electrical recovery performance of the environmentally friendly mixed gas meets the breaking requirements if the electric field distribution at each point in the arc extinguishing chamber is not less than the critical discharge field strength. Improve the structural design submodule to improve the structural design of the parts of the arc extinguishing chamber where the electric field distribution is less than the critical discharge field strength, so that the hot environmentally friendly mixed gas has the electrical recovery performance that meets the breaking requirements.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-5.

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