Method for evaluating weight and overload resistance of laminated iron core of distribution transformer

Abstract

The invention discloses a method for evaluating the weight and overload resistance of a laminated iron core of a distribution transformer, which comprises the following steps of: obtaining nameplate parameters of the distribution transformer and a sound level measurement type test result, and measuring the noise sound pressure of the distribution transformer after the distribution transformer stably operates for 30 minutes under different load rates; and measuring the surface temperature rise of the laminated core of the distribution transformer after stable operation for different time under 1.4 times of load rate, thereby calculating a noise factor and a temperature rise factor, and finally determining a laminated core overload factor to evaluate the heavy overload resistance of the laminated core of the distribution transformer. The method has the advantages that the method for evaluating the weight and overload resistance of the laminated iron core of the distribution transformer is provided, and a method can be provided for production optimization design and service performance evaluation of the laminated iron core of the distribution transformer.

Description

Technical Field

[0001] The invention belongs to the field of electrical equipment status assessment, and in particular relates to a method for assessing the heavy overload resistance capacity of a distribution transformer laminated core. Background Art

[0002] The power industry is the foundation and lifeblood of the entire national economy. After 1949, China's power industry has made great progress, and the power supply and demand situation has experienced a development process from severe shortages in the past to the current basic balance. The distribution transformer is the core equipment of the distribution network. It converts AC power of one voltage into AC power of another voltage to meet the power needs of users. Its safe and stable operation is crucial to the power industry.

[0003] Due to the volatility of power load, distribution transformers may face heavy overload conditions. Due to the special structure of the distribution transformer core, under heavy overload conditions, there will be increased heat generation, aggravated magnetostriction, and increased noise. If the core's heavy overload resistance is insufficient, the life of the transformer will be abnormally reduced and the normal life of nearby residents will be affected. However, there is currently no accurate and fast method to judge the heavy overload resistance of the distribution transformer core. Therefore, in order to ensure the long-term safe and stable operation of the distribution transformer, there is an urgent need for an evaluation method for the heavy overload resistance of the distribution transformer core. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating the heavy overload resistance of a distribution transformer laminated core, wherein the distribution transformer is a three-phase structure, and the core is made of laminated silicon steel sheets, comprising the following steps:

[0005] 1) Obtain the nameplate parameters and sound level test results of the distribution transformer, including rated capacity Q and rated sound pressure H;

[0006] 2) According to the rated capacity Q of the distribution transformer, the noise pressure of the distribution transformer after stable operation for 30 minutes at 0.6 times, 0.8 times, 1.0 times, 1.2 times, and 1.4 times the load rate is measured. i , H i The noise pressure of the distribution transformer after stable operation for 30 minutes at i times Q, i can be 0.6, 0.8, 1.0, 1.2, 1.4;

[0007] 3) According to the rated capacity Q of the distribution transformer, the surface temperature rise of the distribution transformer core after stable operation for 15min, 30min, 45min and 60min at a load rate of 1.4 times is measured as T p , T p The surface temperature rise of the core of the distribution transformer after stable operation p min at 1.4 times Q, p can be 15, 30, 45, 60;

[0008] 4) According to the test results of 2) and 3), the noise factor α and temperature rise factor β are obtained:

[0009]

[0010] In the formula, f is the influencing factor related to the material of silicon steel sheet;

[0011] 5) Evaluate the heavy overload resistance of the distribution transformer core according to the core overload factor:

[0012] η=jα+kβ(3)

[0013] Where η is the overload factor of the laminated core, j and k are empirical coefficients related to the installation environment of the distribution transformer. If η≤1, it is considered that the distribution transformer laminated core's heavy overload resistance capacity is qualified, otherwise it is considered that there is a problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The figure shows a flow chart for evaluating the heavy overload capacity of the laminated core of a distribution transformer. DETAILED DESCRIPTION

[0015] The implementation process of the present invention will be further described in detail below in conjunction with the accompanying drawings. Figure 1 The process includes the following steps:

[0016] 1) Obtain the nameplate parameters and sound level test results of the distribution transformer, including rated capacity Q and rated sound pressure H;

[0017] 2) According to the rated capacity Q of the distribution transformer, the noise pressure of the distribution transformer after stable operation for 30 minutes at 0.6 times, 0.8 times, 1.0 times, 1.2 times, and 1.4 times the load rate is measured. i , H i The noise pressure of the distribution transformer after stable operation for 30 minutes at i times Q, i can be 0.6, 0.8, 1.0, 1.2, 1.4;

[0018] 3) According to the rated capacity Q of the distribution transformer, the surface temperature rise of the distribution transformer core after stable operation for 15min, 30min, 45min and 60min at a load rate of 1.4 times is measured as T p , T p The surface temperature rise of the core of the distribution transformer after stable operation p min at 1.4 times Q, p can be 15, 30, 45, 60;

[0019] 4) According to the test results of 2) and 3), the noise factor α and temperature rise factor β are obtained:

[0020]

[0021] In the formula, f is the influencing factor related to the material of silicon steel sheet;

[0022] 5) Evaluate the heavy overload resistance of the distribution transformer core according to the core overload factor:

[0023] η=jα+kβ(3)

[0024] Where η is the overload factor of the laminated core, j and k are empirical coefficients related to the installation environment of the distribution transformer. If η≤1, it is considered that the distribution transformer laminated core's heavy overload resistance capacity is qualified, otherwise it is considered that there is a problem.

[0025] The beneficial effect of the present invention is that a method for evaluating the heavy overload resistance of the distribution transformer laminated core is proposed, which can provide a method for the production optimization design and service performance evaluation of the distribution transformer laminated core.

Claims

1. A method for evaluating the heavy overload resistance of a distribution transformer core, characterized in that: The distribution transformer is a three-phase structure, and the core is made of stacked silicon steel sheets, including the following steps: 1) Obtain the nameplate parameters and sound level test results of the distribution transformer, including rated capacity Q and rated sound pressure H; 2) According to the rated capacity Q of the distribution transformer, the noise pressure of the distribution transformer after stable operation for 30 minutes at 0.6 times, 0.8 times, 1.0 times, 1.2 times, and 1.4 times the load rate is measured. i , H i The noise pressure of the distribution transformer after stable operation for 30 minutes at i times Q, i can be 0.6, 0.8, 1.0, 1.2, 1.4; 3) According to the rated capacity Q of the distribution transformer, the surface temperature rise of the distribution transformer core after stable operation for 15min, 30min, 45min and 60min at a load rate of 1.4 times is measured as T p , T p The surface temperature rise of the core of the distribution transformer after stable operation p min at 1.4 times Q, p can be 15, 30, 45, 60; 4) According to the test results of 2) and 3), the noise factor α and temperature rise factor β are obtained: In the formula, f is the influencing factor related to the material of silicon steel sheet; 5) Evaluate the heavy overload resistance of the distribution transformer core according to the core overload factor: η=jα+kβ(3) Where η is the overload factor of the laminated core, j and k are empirical coefficients related to the installation environment of the distribution transformer. If η≤1, it is considered that the distribution transformer laminated core's heavy overload resistance capacity is qualified, otherwise it is considered that there is a problem.

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