An evaluation method for the overload tolerance of distribution transformers in high altitude environments

Abstract

The present invention discloses a method for evaluating the overload tolerance of a distribution transformer in a high-altitude environment. This method simulates the operation of the distribution transformer in different high-altitude environments, obtains the power factor evaluation factor and the hot spot temperature evaluation factor of the distribution transformer under different high-altitude environments, finally determines the overload tolerance evaluation factor of the distribution transformer, and verifies the overload tolerance of the distribution transformer. The present invention uses the overload tolerance evaluation factor of the distribution transformer to evaluate the overload tolerance of the distribution transformer, can accurately and quickly evaluate the overload tolerance of the distribution transformer in a high-altitude environment, and provides a basis for the evaluation and selection of distribution transformers in a high-altitude environment.

Description

Technical Field

[0001] The present invention belongs to the field of testing and evaluating the overload resistance performance of electrical equipment, and particularly relates to a method for evaluating the overload capacity of distribution transformers in high-altitude environments. Background Technique

[0002] High-altitude areas are characterized by low air pressure, thin air, large temperature fluctuations, strong sunlight during the day, and extremely low temperatures at night. Due to the low oxygen content in high-altitude areas, the thermal conductivity of insulating materials will also decrease, affecting the heat dissipation of distribution transformers, and thus leading to an increase in the winding temperature of distribution transformers; moreover, the environment in high-altitude areas is relatively dry, which will cause the insulating materials of distribution transformers to age and deteriorate, resulting in a decline in insulation performance. Low air pressure will reduce the electrical clearance of electrical equipment and easily cause insulation breakdown; furthermore, it will reduce the overload resistance capacity of distribution transformers and affect the normal operation of distribution transformers. With the increasing demand for distribution transformers in high-altitude environments, the overload problem of distribution transformers has become increasingly prominent. Evaluating the overload capacity of distribution transformers operating in high-altitude environments is a necessary means to ensure the safe and reliable operation of distribution transformers, and it can select distribution transformers suitable for high-altitude environments. However, there is currently a lack of an effective method for evaluating the overload capacity of distribution transformers in high-altitude environments. Therefore, there is an urgent need for a method for evaluating the overload capacity of distribution transformers in high-altitude environments. Summary of the Invention

[0003] Aiming at the above technical problems, the purpose of the present invention is to propose a method for evaluating the overload capacity of distribution transformers in high-altitude environments, which can effectively evaluate the overload capacity of distribution transformers. The method is characterized by including the following steps:

[0004] The first step: Obtain the operating parameters of the distribution transformer

[0005] According to the operation records, obtain the average hot-spot temperature of the distribution transformer winding, denoted as T0, with the unit of K; according to the operation records, obtain the average load multiple of the distribution transformer, denoted as K0; according to the operation records, obtain the average atmospheric pressure of the distribution transformer operating environment, denoted as P0, with the unit of kPa; according to the operation records, obtain the average power factor of the distribution transformer, denoted as cosφ0;

[0006] The second step: Determine the power factor evaluation factor of the distribution transformer in different high-altitude environments

[0007] Simulate a distribution transformer with an overload multiple of 1.6 and a continuous operation time of 45 minutes operating in different high-altitude environments. Use different atmospheric pressures to simulate different high-altitude environments, and set 6 groups of decreasing atmospheric pressures P i, which are P1 = 78.9 kPa, P2 = 72.84 kPa, P3 = 67.24 kPa, P4 = 61.64 kPa, P5 = 56.04 kPa, P6 = 50.44 kPa respectively, measure the power factor of the distribution transformer corresponding to different atmospheric pressure environments. i = 1, 2, 3, 4, 5, 6, is the power factor of the distribution transformer corresponding to the atmospheric pressure P1;

[0008] Obtain the power factor evaluation factor μ under different high altitude environments through formula (1):

[0009]

[0010] Step 3: Determine the hot spot temperature evaluation factor of the distribution transformer under different high altitude environments

[0011] Simulate a distribution transformer with an overload multiple of 1.6 and a continuous operation time of 45 minutes operating in different high altitude environments. Use different atmospheric pressures to simulate different high altitude environments, and set 6 groups of decreasing atmospheric pressures P j , which are P1 = 78.9 kPa, P2 = 72.84 kPa, P3 = 67.24 kPa, P4 = 61.64 kPa, P5 = 56.04 kPa, P6 = 50.44 kPa respectively, measure the hot spot temperature T of the distribution transformer winding corresponding to different atmospheric pressure environments j , in units of K, j = 1, 2, 3, 4, 5, 6, T1 is the hot spot temperature of the distribution transformer winding corresponding to the atmospheric pressure P1;

[0012] Obtain the hot spot temperature evaluation factor β under different high altitude environments through formula (2):

[0013]

[0014] Step 4: Determine the overload tolerance evaluation factor of the distribution transformer

[0015] Calculate the overload tolerance evaluation factor α of the distribution transformer using formula (3):

[0016]

[0017] Step 5: Evaluate the overload tolerance of the distribution transformer

[0018] Evaluate the overload tolerance of the distribution transformer in high altitude environments according to formula (3). If α ≤ 13.7, it is considered that the overload tolerance of the distribution transformer in high altitude environments is qualified; otherwise, it is considered that there is a problem and improvement or material replacement is required.

[0019] The beneficial effects of the present invention are as follows: Considering the actual operating environment of distribution transformers, an evaluation method for the overload tolerance of distribution transformers in high-altitude environments is proposed, which can provide necessary data support for the production design optimization and overload tolerance evaluation of distribution transformers. Description of the Drawings

[0020] Figure 1 It shows a flowchart of an evaluation method for the overload tolerance of distribution transformers in high-altitude environments. Detailed Embodiments

[0021] The present invention will be further described below in conjunction with the drawings and specific implementation processes; it should be emphasized that the specific implementation cases described here are only used to explain the present invention and do not limit the scope of the concept and claims of the present invention; for those skilled in the art, the omission of some well-known structures and their descriptions in the drawings can be understood. An evaluation method for the overload tolerance of distribution transformers in high-altitude environments includes the following steps:

[0022] The first step: Obtain the operating parameters of the distribution transformer

[0023] According to the operation records, obtain the average hot-spot temperature of the distribution transformer winding, denoted as T0, with the unit of K; according to the operation records, obtain the average load multiple of the distribution transformer, denoted as K0; according to the operation records, obtain the average atmospheric pressure of the distribution transformer operating environment, denoted as P0, with the unit of kPa; according to the operation records, obtain the average power factor of the distribution transformer, denoted as

[0024] The second step: Determine the power factor evaluation factors of the distribution transformer in different high-altitude environments

[0025] Simulate a distribution transformer with an overload multiple of 1.6 and a continuous operation time of 45 minutes operating in different high-altitude environments. Use different atmospheric pressures to simulate different high-altitude environments, and set 6 groups of decreasing atmospheric pressures P i , which are P1 = 78.9 kPa, P2 = 72.84 kPa, P3 = 67.24 kPa, P4 = 61.64 kPa, P5 = 56.04 kPa, P6 = 50.44 kPa, and measure the power factor of the corresponding distribution transformer in different atmospheric pressure environments i = 1, 2, 3, 4, 5, 6, is the power factor of the corresponding distribution transformer under the atmospheric pressure P1;

[0026] Obtain the power factor evaluation factor μ in different high-altitude environments through formula (1):

[0027]

[0028] Step 3: Determine the hot-spot temperature evaluation factor of the distribution transformer in different high-altitude environments

[0029] Simulate a distribution transformer with an overload multiple of 1.6 and a continuous operation time of 45 minutes operating in different high-altitude environments. Different high-altitude environments are simulated with different atmospheric pressures, and 6 groups of decreasing atmospheric pressures P j are set, namely P1 = 78.9 kPa, P2 = 72.84 kPa, P3 = 67.24 kPa, P4 = 61.64 kPa, P5 = 56.04 kPa, P6 = 50.44 kPa. Measure the hot-spot temperature T j of the distribution transformer winding corresponding to different atmospheric pressure environments, with the unit of K, j = 1, 2, 3, 4, 5, 6. T1 is the hot-spot temperature of the distribution transformer winding corresponding to the atmospheric pressure P1;

[0030] Obtain the hot-spot temperature evaluation factor β in different high-altitude environments through formula (2):

[0031]

[0032] Step 4: Determine the overload capacity evaluation factor of the distribution transformer

[0033] Calculate the overload capacity evaluation factor α of the distribution transformer using formula (3):

[0034]

[0035] Step 5: Evaluate the overload capacity of the distribution transformer

[0036] Evaluate the overload capacity of the distribution transformer in high-altitude environments according to formula (3). If α ≤ 13.7, it is considered that the overload capacity of the distribution transformer in high-altitude environments is qualified; otherwise, it is considered that there are problems and improvements or material replacements are required.

[0037] The beneficial effect of the present invention is that considering the actual operating environment of the distribution transformer, a method for evaluating the overload capacity of the distribution transformer in high-altitude environments is proposed, which can provide necessary data support for the production design optimization and overload capacity evaluation of the distribution transformer.

Claims

1. An evaluation method for the overload tolerance of distribution transformers in high-altitude environments, characterized in that, It includes the following steps: The first step: Obtain the operating parameters of the distribution transformer Obtain the average hot-spot temperature of the distribution transformer winding according to the operation record, denoted as T0, with the unit of K; Obtain the average load multiple of the distribution transformer based on the operation record, denoted as K0; obtain the average atmospheric pressure of the operating environment of the distribution transformer based on the operation record, denoted as P0, with the unit of kPa; obtain the average power factor of the distribution transformer based on the operation record, denoted as The second step: Determine the power factor evaluation factor of the distribution transformer in different high-altitude environments Simulate a distribution transformer with an overload multiple of 1.6 and a continuous operation time of 45 minutes operating in different high-altitude environments. Different high-altitude environments are simulated with different atmospheric pressures, and 6 groups of decreasing atmospheric pressures P are set i , which are P1 = 78.9 kPa, P2 = 72.84 kPa, P3 = 67.24 kPa, P4 = 61.64 kPa, P5 = 56.04 kPa, P6 = 50.44 kPa, and measure the power factor of the corresponding distribution transformer under different atmospheric pressure environments i = 1, 2, 3, 4, 5, 6, is the power factor of the corresponding distribution transformer under the atmospheric pressure P1; Obtain the power factor evaluation factor μ in different high-altitude environments through formula (1): The third step: Determine the hot-spot temperature evaluation factor of the distribution transformer in different high-altitude environments Simulate a distribution transformer with an overload multiple of 1.6 and a continuous operation time of 45 minutes operating in different high-altitude environments. Different high-altitude environments are simulated with different atmospheric pressures, and 6 groups of decreasing atmospheric pressures P are set j , which are P1 = 78.9 kPa, P2 = 72.84 kPa, P3 = 67.24 kPa, P4 = 61.64 kPa, P5 = 56.04 kPa, P6 = 50.44 kPa respectively. Measure the hot-spot temperature T of the distribution transformer winding corresponding to different atmospheric pressure environments j , with the unit of K, j = 1, 2, 3, 4, 5, 6, and T1 is the hot-spot temperature of the distribution transformer winding corresponding to the atmospheric pressure P1; Obtain the hot-spot temperature evaluation factor β in different high-altitude environments through formula (2): The fourth step: Determine the overload tolerance evaluation factor of the distribution transformer Calculate the overload tolerance evaluation factor α of the distribution transformer using formula (3): The fifth step: Evaluate the overload tolerance of the distribution transformer Evaluate the overload tolerance of the distribution transformer in the high-altitude environment according to formula (3). If α ≤ 13.7, it is considered that the overload tolerance of the distribution transformer in the high-altitude environment is qualified; otherwise, it is considered that there is a problem and improvement or material replacement is required.

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