Method for fast selection of temperature rise test current

Abstract

The embodiment of the present application discloses a kind of methods for quickly selecting temperature rise test current, it is related to the field of power fitting temperature rise and thermal cycle test.The method obtains the test steady-state temperature rise value of reference conductor when reaching test time according to the relationship between the steady-state temperature rise value of reference conductor and the temperature rise value and time of reference conductor and test temperature rise value.According to the relationship between steady-state temperature rise value and the current value of current in power loop, the relationship between test current value, test steady-state temperature rise value, target steady-state temperature rise value of reference conductor and target current value of current in power loop when reaching target steady-state temperature rise value is obtained, and target current value is obtained.This avoids the process of continuously groping target current value by test personnel, and target current value can be obtained by the method of the present application through current with test current value and test time, which saves test time and improves test efficiency.Meanwhile, the test current value will not cause irreversible damage to power loop.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power fittings temperature rise and thermal cycle test, and particularly relates to a method for quickly selecting a temperature rise test current. BACKGROUND

[0002] In the power fittings temperature rise and thermal cycle test standard, a target steady-state temperature rise value of a reference conductor is specified, but the current that should be passed to obtain the required target steady-state temperature rise value is not specified.

[0003] The size of the general current needs to be constantly explored by test personnel according to experience, which is time-consuming, especially for some special conductors. Moreover, the sample product is inevitably damaged irreversibly in the process of exploring the test current. SUMMARY

[0004] Therefore, it is necessary to provide a method for quickly selecting a temperature rise test current, aiming to solve the technical problems that the temperature rise test current is obtained for a long time and is complicated, and the sample product is easily damaged irreversibly.

[0005] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0006] The method for quickly selecting a temperature rise test current has the following steps:

[0007] Obtaining a steady-state temperature rise value of a reference conductor in a power supply loop and a relationship between the temperature rise value of the reference conductor and time;

[0008] Obtaining a relationship between the steady-state temperature rise value and a current value passed in the power supply loop;

[0009] Passing a current with a test current value into the power supply loop, the test current value will not cause irreversible damage to the power supply loop;

[0010] Obtaining a test temperature rise value of the reference conductor within a test time, the test time being less than a time for the reference conductor to reach a steady-state temperature rise;

[0011] According to the relationship between the steady-state temperature rise value of the reference conductor and the temperature rise value of the reference conductor and time and the test temperature rise value, a test steady-state temperature rise value of the reference conductor when the test time is reached is obtained; and

[0012] According to the relationship between the steady-state temperature rise value and the current value passed in the power supply loop, a relationship between the test current value, the test steady-state temperature rise value, a target steady-state temperature rise value of the reference conductor and a target current value passed in the power supply loop when the target steady-state temperature rise value is reached is obtained, and the target current value is obtained.

[0013] In some embodiments of the method for rapidly selecting the temperature rise test current, the steady-state temperature rise of the reference conductor is related to the temperature rise of the reference conductor and time by the following formula:

[0014]

[0015] Where τ(t) is the temperature rise value of the reference conductor, τ s The steady-state temperature rise is given by t, where t is time, T is the thermal time constant, ω is the attenuation coefficient of the change in resistance, and e is the natural exponent with a value of 2.72.

[0016] In some embodiments of the method for rapidly selecting the temperature rise test current, the steady-state temperature rise value is related to the current value flowing into the energized circuit as being proportional to the square of the current value flowing into the energized circuit.

[0017] In some embodiments of the method for rapidly selecting the temperature rise test current, the specific steps for obtaining the test temperature rise value of the reference conductor during the test time are as follows:

[0018] The test time is evenly divided into multiple time nodes, and the temperature value of the reference conductor is measured when each time node is reached to obtain the test temperature rise value.

[0019] In some embodiments of the method for rapidly selecting the temperature rise test current, the time interval between each time node is 1 minute.

[0020] In some embodiments of the method for rapidly selecting the temperature rise test current, the relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value for the energized circuit when the target steady-state temperature rise value is reached is as follows:

[0021]

[0022] Among them, I 试验 Let τ be the test current value. s,试验 τ is the steady-state temperature rise value of the test. s,目标 I represents the target steady-state temperature rise value. 目标 The target current value;

[0023] The target current value is obtained as follows:

[0024]

[0025] In some embodiments of the method for rapidly selecting the temperature rise test current, the energized circuit includes the reference conductor and power fittings electrically connected to the reference conductor.

[0026] In some embodiments of the method for rapidly selecting the temperature rise test current, the test time is 20 minutes.

[0027] In some embodiments of the method for rapidly selecting the temperature rise test current, the test current value is 500A.

[0028] Implementing the embodiments of the present invention will have the following beneficial effects:

[0029] The aforementioned method for rapidly selecting the temperature rise test current can quickly obtain the target current value for the energized circuit when the target steady-state temperature rise value is reached, saving test time and reducing the complexity of the process, while also avoiding irreversible damage to the sample product. Specifically, this method obtains the test steady-state temperature rise value of the reference conductor at the test time based on the steady-state temperature rise value of the reference conductor, the relationship between the reference conductor's temperature rise value and time, and the test temperature rise value. Based on the relationship between the steady-state temperature rise value and the current value in the energized circuit, the relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value for the energized circuit when the target steady-state temperature rise value is reached is obtained, thus yielding the target current value. This avoids the process of test personnel constantly searching for the target current value; the target current value can be obtained using the known current with the test current value and the test time, saving test time and improving test efficiency. Simultaneously, this test current value will not cause irreversible damage to the energized circuit, avoiding damage to the energized circuit after the test, facilitating subsequent testing and use of the energized circuit, and saving costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] in:

[0032] Figure 1 This is a flowchart of a method for rapidly selecting the temperature rise test current in one embodiment. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0036] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0037] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0038] The standard for temperature rise and thermal cycling tests of power fittings specifies the target steady-state temperature rise value of the reference conductor, but does not specify the current that should be applied to obtain the required target steady-state temperature rise value.

[0039] The optimal current usually requires experimentation by the tester, which is time-consuming, especially for certain special wires. Furthermore, the process of determining the optimal test current can sometimes cause irreversible damage to the sample product.

[0040] To solve the above-mentioned technical problems, the present invention provides a method for rapidly selecting the temperature rise test current. For example... Figure 1 As shown, the method has the following steps:

[0041] Obtain the steady-state temperature rise of a reference conductor in the energized circuit and the relationship between the temperature rise of the reference conductor and time;

[0042] Obtain the relationship between the steady-state temperature rise value and the current value flowing into the energized circuit;

[0043] A test current value is supplied to the energized circuit, the test current value of which will not cause irreversible damage to the energized circuit;

[0044] The test temperature rise value of the reference conductor is obtained within the test time, wherein the test time is less than the time it takes for the reference conductor to reach a steady-state temperature rise;

[0045] Based on the steady-state temperature rise of the reference conductor, the relationship between the temperature rise of the reference conductor and time, and the test temperature rise, the test steady-state temperature rise of the reference conductor at the time specified in the test is obtained; and

[0046] Based on the relationship between the steady-state temperature rise value and the current value flowing into the energized circuit, the relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value flowing into the energized circuit when the target steady-state temperature rise value is reached is obtained, and the target current value is obtained.

[0047] In summary, implementing the embodiments of the present invention will have the following beneficial effects: The method for rapidly selecting the temperature rise test current described above can quickly obtain the target current value of the circuit when the target steady-state temperature rise value is reached, saving test time and reducing the complexity of the process, and avoiding irreversible damage to the sample product. Specifically, this method obtains the test steady-state temperature rise value of the reference conductor at the time of the test based on the steady-state temperature rise value of the reference conductor, the relationship between the temperature rise value of the reference conductor and time, and the test temperature rise value. Based on the relationship between the steady-state temperature rise value and the current value in the circuit, the relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value of the circuit when the target steady-state temperature rise value is reached is obtained, thus obtaining the target current value. This avoids the process of test personnel constantly searching for the target current value; the target current value can be obtained by using the method of the present invention with a known test current value and test time, saving test time and improving test efficiency. Meanwhile, the test current value will not cause irreversible damage to the energized circuit, avoiding damage to the energized circuit after the test, facilitating subsequent testing and use of the energized circuit, and saving costs.

[0048] In one embodiment, the steady-state temperature rise of the reference conductor is related to the temperature rise of the reference conductor and time by the following formula:

[0049]

[0050] Where τ(t) is the temperature rise value of the reference conductor, τ s Here, t represents the steady-state temperature rise, T is the thermal time constant, ω is the decay coefficient of the change in resistance, and e is the natural exponent with a value of 2.72. The above formula is the derived temperature rise equation for electrothermal heating. This equation describes the relationship between the temperature rise of a current-carrying circuit and time after a certain current is applied. Thus, the steady-state temperature rise can be obtained by using the above formula after obtaining the temperature rise of a reference conductor and the time, where time is the time corresponding to obtaining the above temperature rise value, that is, the time corresponding to the temperature rise value being reached after the current is applied to the current-carrying circuit.

[0051] In one embodiment, the steady-state temperature rise is proportional to the square of the current flowing through the energized circuit. Thus, within the same energized circuit, by knowing one set of steady-state temperature rises and the current values ​​in the circuit, as well as another steady-state temperature rise, the corresponding current value can be obtained. If a predetermined temperature needs to be reached, a suitable current value can be selected using this relationship.

[0052] In one embodiment, the specific steps for obtaining the test temperature rise value of the reference conductor during the test time are as follows:

[0053] The test time is evenly divided into multiple time nodes, and the temperature value of the reference conductor is measured at each time node to obtain the test temperature rise value. The smaller the interval between the time nodes, the higher the measurement accuracy. In this embodiment, the interval between each time node is 1 minute.

[0054] Furthermore, based on the relationship between the steady-state temperature rise of the reference conductor and the temperature rise of the reference conductor over time, and the various experimental temperature rise values, a nonlinear fitting is performed to obtain the experimental steady-state temperature rise of the reference conductor within the experimental time. This allows for the prediction of the experimental steady-state temperature rise of the reference conductor within a relatively short timeframe.

[0055] In one embodiment, the relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value of the energized circuit when the target steady-state temperature rise value is reached is as follows:

[0056]

[0057] Among them, I 试验 Let τ be the test current value. s,试验 τ is the steady-state temperature rise value of the test. s,目标 I represents the target steady-state temperature rise value. 目标 The target current value;

[0058] The target current value is obtained as follows:

[0059]

[0060] The target current value required for the target steady-state temperature rise can be calculated using the above formula. By obtaining the test current value and the test steady-state temperature rise value during the experimental stage, the target current value can be obtained in a single test, avoiding the need for test personnel to continuously explore based on experience to obtain the original target current value, thus saving time. At the same time, the test current value used is relatively small, which will not cause irreversible damage to the energized circuit.

[0061] In one embodiment, the energized circuit includes a reference conductor and power fittings electrically connected to the reference conductor. The number of power fittings can be multiple to simulate real-world usage conditions. In this embodiment, the test duration is 20 minutes to ensure a sufficient number of time points during the experiment to obtain a greater number of temperature values, facilitating nonlinear fitting. Simultaneously, a short test time is ensured, improving test efficiency. Furthermore, the test current value is 500A, which avoids irreversible damage to the energized circuit while ensuring a significant temperature rise in the reference conductor and a clear difference between the temperature values ​​obtained at each time point.

[0062] The method for rapidly selecting the temperature rise test current according to the present invention is illustrated below through a specific embodiment. The specific steps of the method are as follows:

[0063] Obtain the steady-state temperature rise of the reference conductor in the energized circuit and the relationship between the temperature rise of the reference conductor and time:

[0064]

[0065] Where τ(t) is the temperature rise value of the reference conductor, τ s Here, t represents the steady-state temperature rise, T is the thermal time constant, ω is the attenuation coefficient of the change in resistance, and e is the natural unit of electric charge, with a value of 1.60217733 × 10⁻¹⁹ coulombs. In this embodiment, the energized circuit includes a reference conductor and two power fittings electrically connected to the reference conductor. The reference conductor is a 240 square millimeter aluminum stranded wire, and the power fittings are JXD wedge clamps.

[0066] The relationship between the steady-state temperature rise and the current flowing through the energized circuit is obtained: the steady-state temperature rise is proportional to the square of the current flowing through the energized circuit.

[0067] A test current (500A) was applied to the energized circuit, and the temperature rise of the reference conductor was measured over 20 minutes. The temperature of the reference conductor was measured every minute. The measurement results are as follows:

[0068]

[0069]

[0070] Based on the steady-state temperature rise of the reference conductor, the relationship between the temperature rise of the reference conductor and time, and each of the test temperature rise values, a nonlinear fitting is performed to obtain the test steady-state temperature rise of the reference conductor within the test time as equal to 48K.

[0071] The relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value (90K) of the reference conductor, and the target current value of the circuit when the target steady-state temperature rise value is reached is obtained:

[0072]

[0073] Among them, I 试验 Let τ be the test current value. s,试验 τ is the steady-state temperature rise value of the test. s,目标 I represents the target steady-state temperature rise value. 目标 The target current value;

[0074] The target current value is obtained as follows:

[0075]

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for rapidly selecting the temperature rise test current, characterized in that... It has the following steps: Obtain the steady-state temperature rise of a reference conductor in the energized circuit and the relationship between the temperature rise of the reference conductor and time; Obtain the relationship between the steady-state temperature rise value and the current value flowing into the energized circuit; A test current value is supplied to the energized circuit, the test current value of which will not cause irreversible damage to the energized circuit; The test temperature rise value of the reference conductor is obtained within the test time, wherein the test time is less than the time it takes for the reference conductor to reach a steady-state temperature rise; Based on the steady-state temperature rise of the reference conductor, the relationship between the temperature rise of the reference conductor and time, and the test temperature rise, the test steady-state temperature rise of the reference conductor at the time of the test is obtained. and Based on the relationship between the steady-state temperature rise value and the current value flowing into the energized circuit, the relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value flowing into the energized circuit when the target steady-state temperature rise value is reached is obtained, and the target current value is obtained.

2. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The steady-state temperature rise of the reference conductor is related to the temperature rise of the reference conductor and time by the following formula: Where τ(t) is the temperature rise value of the reference conductor, τ s The steady-state temperature rise is given by t, where t is time, T is the thermal time constant, ω is the attenuation coefficient of the change in resistance, and e is the natural exponent with a value of 2.

72.

3. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The steady-state temperature rise is proportional to the square of the current flowing through the energized circuit.

4. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The specific steps for obtaining the test temperature rise value of the reference conductor during the test time are as follows: The test time is evenly divided into multiple time nodes, and the temperature value of the reference conductor is measured when each time node is reached to obtain the test temperature rise value.

5. The method for rapidly selecting the temperature rise test current according to claim 4, characterized in that, The time interval between each of the aforementioned time nodes is 1 minute.

6. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The relationship between the test current value, the test steady-state temperature rise value, the target steady-state temperature rise value of the reference conductor, and the target current value of the circuit when the target steady-state temperature rise value is reached is as follows: Among them, I 试验 Let τ be the test current value. s,试验 τ is the steady-state temperature rise value of the test. s,目标 I represents the target steady-state temperature rise value. 目标 The target current value; The target current value is obtained as follows:

7. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The energized circuit includes the reference conductor and power fittings electrically connected to the reference conductor.

8. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The test lasted for 20 minutes.

9. The method for rapidly selecting the temperature rise test current according to claim 1, characterized in that, The test current value is 500A.

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