CN110320450A - A kind of lifetime estimation method and system of saturable reactor aging insulating materials - Google Patents
A kind of lifetime estimation method and system of saturable reactor aging insulating materials Download PDFInfo
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Abstract
A kind of lifetime estimation method and system of saturable reactor aging insulating materials, comprising: the aging accelerated test based on saturable reactor aging insulating materials obtains breakdown time of the insulating materials when external electric field at the uniform velocity increases；The relationship of the breakdown time of breakdown time based on insulating materials when external electric field at the uniform velocity increases with the insulating materials being determined by experiment in advance in constant voltage obtains breakdown time of the insulating materials in constant voltage；The service life of insulating materials is assessed according to the field strength of breakdown time and aging accelerated test of the insulating materials in constant voltage.Technical method of the invention assesses the service life of insulating materials and saturable reactor entirety from the result of test, help to improve the reliability of saturable reactor, the converter valve service life is optimized, the demand of the transmission line capability increasingly increased is met, there is very strong engineering application value.
Description
Technical Field
The invention belongs to the field of extra-high voltage direct current transmission converter valves in power electronics, and particularly relates to a service life assessment method and system for an insulation material for saturable reactor aging.
Background
The saturable reactor is used for protecting the thyristor. At the moment when the thyristor is switched on, the saturable reactor presents very large impedance, so that the over-fast increase of the switching-on surge current is inhibited; at the moment, the saturable reactor can also play a damping role, so that the zero crossing of the first trough current is avoided. In addition, the saturable reactor will also take up most of the peak voltage in case of lightning overvoltage, thereby reducing the voltage stress of the thyristor. As the load current increases, the saturable reactor will gradually saturate, thus not increasing the active and reactive power losses of the converter valve.
After the saturable reactor fails: in the initial stage of the turn-on of the converter valve, because of the over-fast increase of the turn-on current (i.e. the di/dt is over-large), a large amount of heat is rapidly accumulated in the gate electrode area of the thyristor, so that the thyristor is damaged due to local overheating (the hot spot is positioned near the central gate electrode); under the condition of overvoltage, the end face discharge damage phenomenon of the thyristor can occur due to insufficient creepage distance and increased creepage current; in the case of a rapid flicker voltage (i.e. an excessive dv/dt), a "displacement current" occurs inside the thyristor due to the PN junction capacitance, thereby causing local overheating damage to the thyristor (hot spot locations are random). It follows that the saturable reactor reliability directly determines the safe operation of the converter valve.
In order to improve the reliability of the saturable reactor, main failure mode and failure rate parameters thereof must be obtained. Generally, the failure mode and the failure rate of the power equipment can be obtained by a statistical method. This approach is undoubtedly the most straightforward, efficient and inexpensive for dc transmission equipment that has been put into operation for many years; however, this approach is clearly not feasible with newly developed devices.
From the electrical design point of view, research work of the saturable reactor is mostly concentrated on aspects of modeling, electrical and mechanical design and the like, research work on an accelerated life test is not carried out, and a functional relation between the service life of the saturable reactor and stress intensity is not deeply researched by people; from the perspective of reliability analysis of a direct-current power transmission system, research work is concentrated on a system level, and system research on the service life of a saturable reactor is not carried out.
Disclosure of Invention
In order to solve the problem that failure modes and failure rate parameters of newly developed equipment cannot be obtained by a statistical method in the prior art, the invention provides a service life evaluation method and a service life evaluation system of an insulation material for saturable reactor aging.
The technical scheme of the invention is as follows:
a life evaluation method of an insulation material for aging of a saturable reactor comprises the following steps:
acquiring breakdown time of the insulating material when an external electric field is increased at a constant speed based on an aging acceleration test of the insulating material for aging of the saturable reactor;
obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of an external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments;
and evaluating the service life of the insulating material according to the breakdown time of the insulating material at constant voltage and the field strength of the aging acceleration test.
Preferably, the experimentally determined relationship of the breakdown time of the insulating material at a constant voltage includes:
acquiring a functional relation between the aging life of the insulating material and the electric field intensity through experiments;
determining a functional relation of the performance of the insulating material along with the change of time according to the functional relation between the aging life of the insulating material and the electric field intensity;
and determining the relation between the uniform voltage boosting breakdown time and the constant voltage breakdown time based on the function relation of the performance of the insulating material changing along with time.
Preferably, the function relationship between the aging life of the insulating material and the electric field intensity obtained by the experiment is calculated by the following formula:
L＝K/En
wherein L represents the aging life of the insulating material; e represents the electric field strength; K. n represents a constant depending on the type of material, aging mechanism, temperature, etc. test conditions.
Preferably, the function relation of the performance of the insulating material changing along with the time is determined by the function relation between the aging life of the insulating material and the electric field intensity, and the function relation is calculated by the following formula:
F(P)＝K1Ent
wherein F (P) represents the property of the insulating material; k1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents time.
Preferably, the determining the relationship between the time of uniform voltage boosting breakdown and the breakdown time of constant voltage based on the function relationship of the property of the insulating material changing with time includes:
if the experimental field strength is constant, the aging life of the insulating material is L, and the aging degree is calculated as follows:
in the formula, F (E)F) Representing a constant field strength of EFThe degree of aging of the underlying insulating material; k1Represents a characteristic constant of the insulating material; eFRepresenting the field strength at which a constant voltage is applied; l represents the aging life of the insulating material; n represents a constant, depending on the type of material, aging mechanism and temperature experimental conditions;
if the experimental field intensity is increased at a constant speed until the insulating material is broken down, the aging degree is calculated as follows:
in the formula, LFIndicating the aging life of the insulating material under the condition of increasing the field intensity at a constant speed;
determining the relation between the time of uniform voltage boosting breakdown and the breakdown time of constant voltage according to the following formula under the condition that the aging degree of the insulating material is equal:
in the formula, t0Denotes the breakdown time, t, of the constant voltage at an aging life L of the insulating materialFIndicating the aging life of the insulating material as LFBreakdown time of the lower constant boost.
Preferably, determining the lifetime of the insulating material according to the breakdown time of the insulating material at a constant voltage comprises:
determining a standard breakdown field strength based on the breakdown time of the constant voltage;
evaluating the lifetime of the insulating material based on the breakdown time and the properties of the insulating material.
Preferably, the standard breakdown field strength is determined based on the breakdown time of the constant voltage, and is calculated as follows:
in the formula, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents the duration of time during which a constant voltage is applied; eFRepresenting the field strength at which a constant voltage is applied; eF0Indicating the standard breakdown field strength.
Preferably, said evaluating the lifetime of the insulating material based on said breakdown time and the properties of the insulating material comprises:
determining the service life of the insulating material for the aging of the saturable reactor according to the breakdown time of the constant voltage and the standard breakdown field strength, and evaluating the service life of the insulating material by designing an aging test according to the following formula:
in the formula, E1Representing a known standard field strength; t is t1Represents the known standard breakdown time; e2Representing the test field strength; t is t2The test time is shown.
Another object of the present invention is to provide a system for evaluating a lifetime of an insulating material for aging of a saturable reactor, including: the device comprises an acquisition module, a conversion determination module and an evaluation module;
the acquisition module is used for acquiring the breakdown time of the insulating material when the external electric field is increased at a constant speed based on an aging acceleration test of the insulating material for the aging of the saturable reactor;
the conversion determining module is used for obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of an external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments;
and the evaluation module is used for evaluating the service life of the insulating material according to the breakdown time of the insulating material at constant voltage and the field intensity of the aging acceleration test.
Preferably, the conversion determination module includes: the method comprises the following steps of obtaining a submodule, a calculating submodule and a determining submodule;
the acquisition submodule is used for acquiring a functional relation between the aging life of the insulating material and the electric field intensity through experiments, and the functional relation is calculated according to the following formula:
L＝K/En
wherein L represents the aging life of the insulating material; e represents the electric field strength; K. n represents a constant depending on the type of material, aging mechanism, temperature, etc. test conditions.
The calculation submodule is used for determining the function relation of the performance of the insulating material along with the change of time according to the function relation between the aging life of the insulating material and the electric field intensity, and the function relation is calculated according to the following formula:
F(P)＝K1Ent
wherein F (P) represents the property of the insulating material, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents time;
and the determining submodule is used for determining the relation between the uniform voltage boosting breakdown time and the constant voltage breakdown time based on the function relation of the performance of the insulating material changing along with the time.
Preferably, the determining sub-module includes: a first calculating unit, a second calculating unit and a determining unit;
the first calculating unit is used for calculating the aging life of the insulating material as L if the experimental field strength is constant, and the aging degree is as follows:
in the formula, F (E)F) Representing a constant field strength of EFDegree of aging of the underlying insulating material, K1Represents a characteristic constant of the insulating material; eFRepresenting the field strength at which a constant voltage is applied; l represents the aging life of the insulating material; n represents a constant, depending on the type of material, aging mechanism and temperature experimental conditions;
the second calculating unit is used for calculating the aging degree if the experimental field intensity is increased at a constant speed until the insulating material is broken down according to the following formula:
in the formula, LFIndicating the aging life of the insulating material under the condition of increasing the field intensity at a constant speed;
the determining unit is used for determining the relation between the uniform-speed boosting breakdown time and the constant-voltage breakdown time according to the following formula under the condition that the aging degrees of the insulating materials are equal:
in the formula, t0Denotes the breakdown time, t, of the constant voltage at an aging life L of the insulating materialFIndicating the aging life of the insulating material as LFBreakdown time of the lower constant boost.
Preferably, the evaluation module includes: a standard breakdown field intensity calculation submodule and an evaluation submodule;
the standard breakdown field strength calculation submodule is used for determining standard breakdown field strength based on the breakdown time of the constant voltage, and the standard breakdown field strength is calculated according to the following formula:
in the formula, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents the duration of time during which a constant voltage is applied; eFRepresenting the field strength at which a constant voltage is applied; eF0Represents the standard breakdown field strength;
and the evaluation submodule is used for evaluating the service life of the insulating material according to the breakdown time and the property of the insulating material.
Preferably, the evaluation sub-module includes: a design unit;
the design unit is used for determining the service life of the insulating material for the aging of the saturable reactor according to the breakdown time of the constant voltage and the standard breakdown field strength, and the service life of the insulating material is estimated by an aging test designed according to the following formula:
in the formula, E1Representing a known standard field strength; t is t1Represents the known standard breakdown time; e2Representing the test field strength; t is t2The test time is shown.
Compared with the prior art, the invention has the beneficial effects that:
according to the technical scheme, the breakdown time of the insulating material is obtained when the external electric field is increased at a constant speed through an aging acceleration test of the insulating material for aging of the saturable reactor; obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of an external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments; the service life of the insulating material is evaluated according to the breakdown time of the insulating material at constant voltage and the field intensity of an aging acceleration test, so that the service life of the insulating material and the service life of the whole saturable reactor are evaluated according to the test result, and the improvement of the reliability of the saturable reactor is facilitated.
The technical scheme of the invention adopts an insulation strength method, provides a new equivalent test method by combining two external electric field conditions of a constant electric field and an external electric field increased at a constant speed, and more conveniently obtains the value of the breakdown field strength of the evaluation standard of the electrical aging life of the insulation material for the saturated reactor, thereby evaluating the aging characteristic and the life of the insulation material;
the technical scheme of the invention adopts an equivalent aging method, and can flexibly design the test field intensity and the test time of the aging test.
Drawings
FIG. 1 is a method for evaluating the life of an insulation material for aging a saturable reactor according to the present invention;
FIG. 2 illustrates the occurrence of partial discharge according to the present invention;
FIG. 3 is a diagram of the novel electrical aging accelerated life test method of the present invention;
figure 4 insulation strength of the present invention as a function of its electrical aging life.
Detailed Description
For a better understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings and examples.
In order to obtain the service life of a saturable reactor which is a key part of a converter valve and predict whether defects exist in the design and process of a product in advance, the invention provides an electrical aging test method suitable for the saturable reactor based on a traditional thermal aging test method. The method of applying a constant electric field first and then applying a uniform increasing electric field is adopted to finish the accelerated aging of the saturable reactor in a shorter time, and the service life of the insulating material for the saturable reactor is evaluated by evaluating the value of the breakdown field strength. The service life of the whole saturable reactor and the insulating material is evaluated according to the test result, the reliability of the saturable reactor is improved, the service life of the converter valve is optimally designed, the safe and reliable operation of the converter valve is ensured, the requirement of increasing power transmission capacity is met, and the engineering application value is very high.
By developing the electric aging test of the saturable reactor which is a key part of the converter valve, the reliability evaluation of the converter valve and the improvement of the product quality can be irreplaceable, the service life of the converter valve can be prolonged, the operation and maintenance cost of a converter station can be reduced, and the technical management level of high-end manufacturing industry can be improved.
The saturable reactor mainly comprises an iron core and a coil. It is a main functional component, and in addition, the elastic body (filler between the core and the case) functions as a shock absorber, and the silicon rubber thin strip functions to buffer direct collision of the core and the coil.
Partial discharge is a cause of aging of the dielectric, and therefore, the life of the insulating material should be evaluated using discharge resistance rather than insulation strength. Some materials have a strong short-term electrical resistance, but have a short long-term service life.
Under the action of alternating voltage:
(1) when the air gap voltage Uc is greater than Uc1, the inside of the air gap is broken down by the strong electric field, creating space charge (i.e., positive and negative ions). At this time, the total voltage Uc on the air gap will immediately drop to Uc2 (U) due to the action of the counter electric field DeltaU formed by the positive and negative ionsc1-Uc2Δ U), the discharge process is extinguished; however, as the applied voltage Ua increases, the air-gap voltage Uc again rises to Uc1, and therefore a second discharge occurs, which also results in a doubling of the space charge. This is repeated until the increase in peak value after the previous discharge quenching is less than Δ U.
(2) After the peak voltage, the applied voltage gradually decreases, and at this time, the difference between the space charge's counter electric field and the air-gap electric field Uc is larger than the breakdown voltage Uc1, and thus, the space charge continues to be discharged. Then, the space charge is gradually reduced, the counter electric field is weakened, and the discharge process is extinguished.
(3) When the external voltage has reversed polarity, the discharge is continuously generated until the discharge process within one week of the external voltage breaks down. As shown in fig. 2.
The magnitude and direction of the direct current voltage are unchanged. Once the air gap is broken down, the space charge immediately builds up a counter field and the discharge extinguishes. Then, space charge leaks through the air gap surface, the reverse electric field is weakened, and a second discharge process occurs. Therefore, the discharge times of the material under the direct-current voltage are few, and the influence on the service life of the medium is small.
As can be seen from fig. 1, a method for evaluating the lifetime of an insulation material for saturable reactor aging, comprising:
s1, obtaining the breakdown time of the insulation material when the external electric field increases at a constant speed based on the aging acceleration test of the insulation material for the aging of the saturable reactor.
S2, obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of the external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments;
further, the experimentally determined relationship of the breakdown time of the insulating material at a constant voltage includes:
acquiring a functional relation between the aging life of the insulating material and the electric field intensity through experiments;
the function relationship between the aging life of the insulating material and the electric field intensity obtained by the experiment is calculated as follows:
L＝K/En
wherein L represents the aging life of the insulating material; e represents the electric field strength; K. n represents a constant depending on the type of material, aging mechanism, temperature, etc. test conditions.
Determining a functional relation of the performance of the insulating material along with the change of time according to the functional relation between the aging life of the insulating material and the electric field intensity;
the function relation of the performance of the insulating material changing along with the time is determined according to the function relation between the aging life of the insulating material and the electric field intensity, and is calculated as the following formula:
F(P)＝K1Ent
wherein F (P) represents the property of the insulating material; k1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents time.
Determining the relation between the uniform voltage boosting breakdown time and the constant voltage breakdown time based on the function relation of the performance of the insulating material changing along with time;
if the experimental field strength is constant, the aging life of the insulating material is L, and the aging degree is calculated as follows:
in the formula, F (E)F) Representing a constant field strength of EFThe degree of aging of the underlying insulating material; k1Represents a characteristic constant of the insulating material; eFRepresenting the field strength at which a constant voltage is applied; l represents the aging life of the insulating material; n represents a constant, depending on the type of material, aging mechanism and temperature experimental conditions;
if the experimental field intensity is increased at a constant speed until the insulating material is broken down, the aging degree is calculated as follows:
in the formula, LFIndicating the aging life of the insulating material under the condition of increasing the field intensity at a constant speed;
determining the relation between the time of uniform voltage boosting breakdown and the breakdown time of constant voltage according to the following formula under the condition that the aging degree of the insulating material is equal:
in the formula, t0Denotes the breakdown time, t, of the constant voltage at an aging life L of the insulating materialFIndicating the aging life of the insulating material as LFBreakdown time of the lower constant boost.
And S3, evaluating the service life of the insulating material according to the breakdown time of the insulating material at constant voltage and the field intensity of the aging acceleration test.
Further, determining a standard breakdown field strength based on the breakdown time of the constant voltage;
the breakdown time based on the constant voltage determines a standard breakdown field strength as calculated by:
in the formula, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents the duration of time during which a constant voltage is applied; eFRepresenting the field strength at which a constant voltage is applied; eF0Indicating the standard breakdown field strength.
According to the breakdown time t0And a property of the insulating material to evaluate the life of the insulating material;
determining the service life of the insulating material for the aging of the saturable reactor according to the breakdown time of the constant voltage and the standard breakdown field strength, and evaluating the service life of the insulating material by designing an aging test according to the following formula:
in the formula, E1Representing a known standard field strength; t is t1Represents the known standard breakdown time; e2Representing the test field strength; t is t2The test time is shown.
Specifically, the following technical scheme is adopted:
similar to the thermal aging test, the performance of the insulation material as a function of time can be expressed as:
f(P)-f(P0) Kt or f (p) kt (1)
Wherein, P0For initial performance, P is the performance corresponding to time t, k ═ Ae-E/RTFor the reaction rate, E is the electric field strength, R is the gas constant,a is the collision coefficient.
Suppose that: at time t ═ L, the insulating material fails, at which time the material degrades to P ═ PPNamely:
F(PP)＝kL (2)
experiments show that the function relation between the aging life L of the insulating material and the electric field intensity E is as follows:
L＝K/En (3)
wherein K and n are constants, and the method depends on the type of the material, the aging mechanism, the temperature and other test conditions.
Combining (2) and (3) to obtain:
namely, it is
Wherein,is a characteristic constant of the insulating material.
The relation of the change function of the performance of the insulating material along with time is as follows:
F(P)＝K1Ent (5)
i. at the test field strength E ═ EFIn the constant case, if the aging life of the insulating material is L:
ii. If the test field strength increases linearly from zero until the material breaks down:
in the case of linear increase in field strength, if L is equal to tFAt the moment, the insulation material breaks down E ═ EFAnd then:
combining i and ii, the time ratio required by the two test methods is as follows under the premise of the same aging degree:
therefore, the time t of uniform boost breakdownFAnd breakdown time t of constant voltage0Can be mutually converted. Namely:
(1) dielectric strength method
Assuming that the short time breakdown strength of the material is EF0Corresponding to an aging life of t0. The test procedure was:
1) applying a constant voltage, stopping the pressurization before the breakdown of the material, i.e. t<t0. As shown in fig. 3.
2) Applying an external electric field (intensity less than E) with uniform velocity increaseF0) At t + tFThe insulation strength of the insulation material is tested at the moment and is recorded as F (E)F). On the premise that the applied field strength is unchanged, if the insulation strength of the insulation material is recorded at different moments, a functional relationship between the insulation strength of the insulation material and the electrical aging life of the insulation material can be obtained, as shown in fig. 4.
It is clear that it comprises two phases. According to the equivalence principle, the insulation strength test of linear boosting can be equivalent to that the electric field is constant to be EFDuration of t0And (5) aging. Thus, the total amount of aging before breakdown is:
from another point of view, the following can be necessarily concluded: at constant field strength EF0(i.e., breakdown field strength of the material), the equivalent breakdown time of the material must be t0. According to the principle of equal aging amount, the following steps are known:
namely, it is
(2) Equivalent aging method
The ageing quantity borne by the material before ageing is irrelevant to the test strength, so that the following formula is known according to the principle of equal ageing quantity, and the test field strength and the test time of the ageing test can be designed according to the formula.
Another objective of the present invention is to provide a saturable reactor aging test system, which is similar in principle to a saturable reactor aging test method, and includes: the device comprises an acquisition module, a conversion determination module and an evaluation module; the three modules are further described below:
the acquisition module is used for acquiring the breakdown time of the insulation material for the aging of the saturable reactor when the external electric field is increased at a constant speed based on an aging acceleration test of the insulation material;
the conversion determining module is used for obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of an external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments;
and the evaluation module is used for evaluating the service life of the insulating material according to the breakdown time of the insulating material at constant voltage and the field intensity of the aging acceleration test.
A conversion determination module comprising: the method comprises the following steps of obtaining a submodule, a calculating submodule and a determining submodule;
and the acquisition submodule is used for acquiring a functional relation between the aging life of the insulating material and the electric field intensity through experiments, and the functional relation is calculated according to the following formula:
L＝K/En
wherein L represents the aging life of the insulating material; e represents the electric field strength; K. n represents a constant depending on the type of material, aging mechanism, temperature, etc. test conditions.
A calculation submodule for determining a time-dependent functional relationship for the properties of the insulating material from the functional relationship between the aging life of the insulating material and the electric field strength, as calculated by:
F(P)＝K1Ent
wherein F (P) represents the property of the insulating material, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents time;
and the determining submodule is used for determining the relation between the time of uniform voltage boosting breakdown and the breakdown time of constant voltage based on the function relation of the performance of the insulating material changing along with time.
A determination submodule comprising: a first calculating unit, a second calculating unit and a determining unit;
the first calculating unit is used for calculating the aging life of the insulating material as L if the experimental field strength is constant, and the aging degree is as follows:
in the formula, F (E)F) Representing a constant field strength of EFDegree of aging of the underlying insulating material, K1Represents a characteristic constant of the insulating material; eFRepresenting the field strength at which a constant voltage is applied; l represents the aging life of the insulating material; n represents a constant, depending on the type of material, aging mechanism and temperature experimental conditions;
the second calculating unit is used for calculating the aging degree if the experimental field intensity is increased at a constant speed until the insulating material breaks down according to the following formula:
in the formula, LFIndicating the aging life of the insulating material under the condition of increasing the field intensity at a constant speed;
the determining unit is used for determining the relation between the time of uniform-speed boosting breakdown and the breakdown time of constant voltage according to the following formula under the condition that the aging degrees of the insulating materials are equal:
in the formula, t0Denotes the breakdown time, t, of the constant voltage at an aging life L of the insulating materialFIndicating the aging life of the insulating material as LFBreakdown time of the lower constant boost.
An evaluation module, comprising: a standard breakdown field intensity calculation submodule and an evaluation submodule;
a standard breakdown field strength calculation submodule for determining a standard breakdown field strength based on the breakdown time of the constant voltage, as calculated by:
in the formula, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents the duration of time during which a constant voltage is applied; eFRepresenting the field strength at which a constant voltage is applied; eF0Represents the standard breakdown field strength;
and the evaluation submodule is used for evaluating the service life of the insulating material according to the breakdown time and the property of the insulating material.
An evaluation sub-module comprising: a design unit;
the design unit is used for determining the service life of the insulating material for the aging of the saturable reactor according to the breakdown time of the constant voltage and the standard breakdown field strength, and the service life of the insulating material is estimated by designing an aging test according to the following formula:
in the formula, E1Representing a known standard field strength; t is t1Represents the known standard breakdown time; e2Representing the test field strength; t is t2The test time is shown.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.
Claims (13)
1. A life evaluation method of an insulation material for saturable reactor aging is characterized by comprising the following steps:
acquiring breakdown time of the insulating material when an external electric field is increased at a constant speed based on an aging acceleration test of the insulating material for aging of the saturable reactor;
obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of an external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments;
and evaluating the service life of the insulating material according to the breakdown time of the insulating material at constant voltage and the field strength of the aging acceleration test.
2. The method of evaluating the lifetime of an insulating material for saturable reactor aging according to claim 1, wherein the experimentally determined relationship of the breakdown time of the insulating material at a constant voltage comprises:
acquiring a functional relation between the aging life of the insulating material and the electric field intensity through experiments;
determining a functional relation of the performance of the insulating material along with the change of time according to the functional relation between the aging life of the insulating material and the electric field intensity;
and determining the relation between the uniform voltage boosting breakdown time and the constant voltage breakdown time based on the function relation of the performance of the insulating material changing along with time.
3. The method of evaluating the lifetime of an insulating material for saturable reactor aging according to claim 2, wherein the functional relationship between the aging lifetime of the insulating material and the electric field intensity obtained by experiment is calculated as follows:
L＝K/En
wherein L represents the aging life of the insulating material; e represents the electric field strength; K. n represents a constant depending on the type of material, aging mechanism, temperature, etc. test conditions.
4. The method of evaluating the lifetime of an insulating material for saturable reactor aging according to claim 2, wherein the functional relationship of the property of the insulating material with time change is determined from the functional relationship between the aging lifetime of the insulating material and the electric field strength as follows:
F(P)＝K1Ent
wherein F (P) represents the property of the insulating material; k1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents time.
5. The method for evaluating the lifetime of an insulating material for saturable reactor aging according to claim 2, wherein determining the relationship between the time of uniform voltage step-up breakdown and the breakdown time of constant voltage based on the functional relationship of the change of the property of the insulating material with time comprises:
if the experimental field strength is constant, the aging life of the insulating material is L, and the aging degree is calculated as follows:
in the formula, F (E)F) Representing a constant field strength of EFThe degree of aging of the underlying insulating material; k1Represents a characteristic constant of the insulating material; eFRepresenting the field strength at which a constant voltage is applied; l represents the aging life of the insulating material; n represents a constant, depending on the type of material, aging mechanism and temperature experimental conditions;
if the experimental field intensity is increased at a constant speed until the insulating material is broken down, the aging degree is calculated as follows:
in the formula, LFIndicating the aging life of the insulating material under the condition of increasing the field intensity at a constant speed;
determining the relation between the time of uniform voltage boosting breakdown and the breakdown time of constant voltage according to the following formula under the condition that the aging degree of the insulating material is equal:
in the formula, t0Denotes the breakdown time, t, of the constant voltage at an aging life L of the insulating materialFIndicating the aging life of the insulating material as LFBreakdown time of the lower constant boost.
6. The method of evaluating the lifetime of an insulating material for saturable reactor aging according to claim 1, wherein determining the lifetime of the insulating material based on a breakdown time of the insulating material at a constant voltage comprises:
determining a standard breakdown field strength based on the breakdown time of the constant voltage;
evaluating the lifetime of the insulating material based on the breakdown time and the properties of the insulating material.
7. The method of evaluating a lifetime of an insulation material for aging of a saturable reactor according to claim 6, wherein the standard breakdown field strength is determined based on the breakdown time of the constant voltage as calculated by the following formula:
in the formula, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents the duration of time during which a constant voltage is applied; eFRepresenting the field strength at which a constant voltage is applied; eF0Indicating the standard breakdown field strength.
8. The method of evaluating the lifetime of an insulating material for saturable reactor aging according to claim 7, wherein said evaluating the lifetime of the insulating material based on the breakdown time and the property of the insulating material comprises:
determining the service life of the insulating material for the aging of the saturable reactor according to the breakdown time of the constant voltage and the standard breakdown field strength, and evaluating the service life of the insulating material by designing an aging test according to the following formula:
in the formula, E1Representing a known standard field strength; t is t1Represents the known standard breakdown time; e2Representing the test field strength; t is t2The test time is shown.
9. A life evaluation system of an insulation material for saturable reactor aging, characterized by comprising: the device comprises an acquisition module, a conversion determination module and an evaluation module;
the acquisition module is used for acquiring the breakdown time of the insulating material when the external electric field is increased at a constant speed based on an aging acceleration test of the insulating material for the aging of the saturable reactor;
the conversion determining module is used for obtaining the breakdown time of the insulating material at constant voltage based on the relation between the breakdown time of the insulating material at the constant-speed increase of an external electric field and the breakdown time of the insulating material at the constant voltage determined in advance through experiments;
and the evaluation module is used for evaluating the service life of the insulating material according to the breakdown time of the insulating material at constant voltage and the field intensity of the aging acceleration test.
10. The system for evaluating a lifetime of an insulation material for saturable reactor aging according to claim 9, wherein the conversion determination module comprises: the method comprises the following steps of obtaining a submodule, a calculating submodule and a determining submodule;
the acquisition submodule is used for acquiring a functional relation between the aging life of the insulating material and the electric field intensity through experiments, and the functional relation is calculated according to the following formula:
L＝K/En
wherein L represents the aging life of the insulating material; e represents the electric field strength; K. n represents a constant depending on the type of material, aging mechanism, temperature, etc. test conditions.
The calculation submodule is used for determining the function relation of the performance of the insulating material along with the change of time according to the function relation between the aging life of the insulating material and the electric field intensity, and the function relation is calculated according to the following formula:
F(P)＝K1Ent
wherein F (P) represents the property of the insulating material, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents time;
and the determining submodule is used for determining the relation between the uniform voltage boosting breakdown time and the constant voltage breakdown time based on the function relation of the performance of the insulating material changing along with the time.
11. The system for evaluating a lifetime of an insulation material for saturable reactor aging according to claim 10, wherein the determination submodule comprises: a first calculating unit, a second calculating unit and a determining unit;
the first calculating unit is used for calculating the aging life of the insulating material as L if the experimental field strength is constant, and the aging degree is as follows:
in the formula, F (E)F) Representing a constant field strength of EFDegree of aging of the underlying insulating material, K1Represents a characteristic constant of the insulating material; eFRepresenting the field strength at which a constant voltage is applied; l represents the aging life of the insulating material; n represents a constant, depending on the type of material, aging mechanism and temperature experimental conditions;
the second calculating unit is used for calculating the aging degree if the experimental field intensity is increased at a constant speed until the insulating material is broken down according to the following formula:
in the formula, LFTo representAging life of the insulating material under the condition of increasing field intensity at a constant speed;
the determining unit is used for determining the relation between the uniform-speed boosting breakdown time and the constant-voltage breakdown time according to the following formula under the condition that the aging degrees of the insulating materials are equal:
in the formula, t0Denotes the breakdown time, t, of the constant voltage at an aging life L of the insulating materialFIndicating the aging life of the insulating material as LFBreakdown time of the lower constant boost.
12. The life evaluation system of the saturable reactor aging insulation material according to claim 9, wherein the evaluation module includes: a standard breakdown field intensity calculation submodule and an evaluation submodule;
the standard breakdown field strength calculation submodule is used for determining standard breakdown field strength based on the breakdown time of the constant voltage, and the standard breakdown field strength is calculated according to the following formula:
in the formula, K1Represents a characteristic constant of the insulating material; e represents the electric field strength; t represents the duration of time during which a constant voltage is applied; eFRepresenting the field strength at which a constant voltage is applied; eF0Represents the standard breakdown field strength;
and the evaluation submodule is used for evaluating the service life of the insulating material according to the breakdown time and the property of the insulating material.
13. The life evaluation system of the saturable reactor aging insulation material according to claim 12, wherein the evaluation submodule includes: a design unit;
the design unit is used for determining the service life of the insulating material for the aging of the saturable reactor according to the breakdown time of the constant voltage and the standard breakdown field strength, and the service life of the insulating material is estimated by an aging test designed according to the following formula:
in the formula, E1Representing a known standard field strength; t is t1Represents the known standard breakdown time; e2Representing the test field strength; t is t2The test time is shown.
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