Assessment method for capacity expansion demand of distribution transformer

Abstract

The invention discloses a distribution transformer capacity expansion demand evaluation method comprising the following steps: obtaining distribution transformer nameplate parameters and factory type test data, and obtaining operation load rate data of a distribution transformer in one year; the average temperature rise of the high-voltage winding and the average temperature rise of the low-voltage winding after stable operation for different time under the maximum operation load rate are measured, and the average temperature rise of the high-voltage winding, the average temperature rise of the low-voltage winding and the sound pressure after stable operation for 60 minutes under the maximum hour average load rate are measured, so that a short-time overload factor and a long-time overload factor are calculated; and finally determining a capacity expansion evaluation factor to evaluate the capacity expansion demand of the distribution transformer. The method has the beneficial effects that the method for evaluating the capacity expansion demand of the distribution transformer is provided, and a method can be provided for evaluating the service performance 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 capacity expansion demand of a distribution transformer. Background Art

[0002] The power industry is the foundation and lifeblood of the entire national economy. After the founding of New China, China's power industry has made great progress. 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. Long-term operation under heavy overload conditions may accelerate the reduction of the life of distribution transformers. In order to ensure the safety and stability of long-term operation of distribution transformers, distribution transformers that cannot meet the needs of substations usually need to be expanded. However, there is currently no accurate and fast method to determine whether distribution transformers need to be expanded. Therefore, in order to ensure the long-term safe and stable operation of distribution transformers, an evaluation method for the expansion needs of distribution transformers is urgently needed. Summary of the invention

[0004] The object of the present invention is to provide a method for evaluating the capacity expansion demand of a distribution transformer, characterized in that the distribution transformer is a three-phase structure, comprising the following steps:

[0005] 1) Obtain the nameplate parameters of the distribution transformer and the type test data at the factory, including the rated capacity Q, the average temperature rise T of the high-voltage winding in the temperature rise type test h , Temperature rise type test low voltage winding average temperature rise T l , sound level determination type test sound pressure H;

[0006] 2) Obtain the operating load rate data of the distribution transformer within one year, including the maximum operating load rate L max , maximum hourly average load rate L h :

[0007] L max =max(L(t))(1)

[0008]

[0009] Where L(t) is the function of the load rate changing with time, t is time, the value range is 0-525600min, i is the intermediate value, i∈{60, 120, ..., 525600};

[0010] 3) According to the calculation results of 2), measure Lmax The average temperature rise of the high-voltage winding and the average temperature rise of the low-voltage winding after the distribution transformer has been running stably for 15min, 30min, 45min, and 60min under the load rate are T hp and T lp , p is the intermediate value, p∈{15, 30, 45, 60};

[0011] 4) Based on the calculation result in 2), measure L h The average temperature rise of the high-voltage winding, the average temperature rise of the low-voltage winding and the sound pressure after the distribution transformer has been running stably for 60 minutes under the load rate are T hh 、T lh and H h ;

[0012] 5) According to the test results of 3) and 4), the short-term overload factor α and long-term overload factor β are obtained:

[0013]

[0014] Where f is the influencing factor related to the installation environment of the distribution transformer;

[0015] 6) Evaluate the demand for expansion of distribution transformers based on the expansion assessment factors:

[0016]

[0017] Where γ is the fan heat dissipation efficiency evaluation factor, d and g are empirical coefficients related to the insulation structure of the distribution transformer. If γ≤1, it is considered that the distribution transformer does not need to be expanded, otherwise it is considered that it needs to be expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It shows a flow chart for evaluating the demand for expansion of distribution transformers. DETAILED DESCRIPTION

[0019] 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:

[0020] 1) Obtain the nameplate parameters of the distribution transformer and the type test data at the factory, including the rated capacity Q, the average temperature rise T of the high-voltage winding in the temperature rise type test h , Temperature rise type test low voltage winding average temperature rise T l , sound level determination type test sound pressure H;

[0021] 2) Obtain the operating load rate data of the distribution transformer within one year, including the maximum operating load rate L max , maximum hourly average load rate L h :

[0022] L max =max(L(t))(1)

[0023]

[0024] Where L(t) is the function of the load rate changing with time, t is time, the value range is 0-525600min, i is the intermediate value, i∈{60, 120, ..., 525600};

[0025] 3) According to the calculation results of 2), measure L max The average temperature rise of the high-voltage winding and the average temperature rise of the low-voltage winding after the distribution transformer has been running stably for 15min, 30min, 45min, and 60min under the load rate are T hp and T lp , p is the intermediate value, p∈{15, 30, 45, 60};

[0026] 4) Based on the calculation result in 2), measure L h The average temperature rise of the high-voltage winding, the average temperature rise of the low-voltage winding and the sound pressure after the distribution transformer has been running stably for 60 minutes under the load rate are T hh 、T lh and H h ;

[0027] 5) According to the test results of 3) and 4), the short-term overload factor α and long-term overload factor β are obtained:

[0028]

[0029] Where f is the influencing factor related to the installation environment of the distribution transformer;

[0030] 6) Evaluate the demand for expansion of distribution transformers based on the expansion assessment factors:

[0031]

[0032] Where γ is the fan heat dissipation efficiency evaluation factor, d and g are empirical coefficients related to the insulation structure of the distribution transformer. If γ≤1, it is considered that the distribution transformer does not need to be expanded, otherwise it is considered that it needs to be expanded.

[0033] The beneficial effect of the present invention is that a method for evaluating the capacity expansion demand of a distribution transformer is proposed, which can provide a method for evaluating the service performance of the distribution transformer.

Claims

1. A method for evaluating the capacity expansion demand of a distribution transformer, characterized in that: The distribution transformer is a three-phase structure, including the following steps: 1) Obtain the nameplate parameters of the distribution transformer and the type test data at the factory, including the rated capacity Q, the average temperature rise T of the high-voltage winding in the temperature rise type test h , Temperature rise type test low voltage winding average temperature rise T l , sound level determination type test sound pressure H; 2) Obtain the operating load rate data of the distribution transformer within one year, including the maximum operating load rate L max , maximum hourly average load rate L h : L max =max(L(t))(1) Where L(t) is the function of the load rate changing with time, t is time, the value range is 0-525600min, i is the intermediate value, i∈{60, 120, ..., 525600}; 3) According to the calculation results of 2), measure L max The average temperature rise of the high-voltage winding and the average temperature rise of the low-voltage winding after the distribution transformer has been running stably for 15min, 30min, 45min, and 60min under the load rate are T hp and T lp , p is the intermediate value, p∈{15, 30, 45, 60}; 4) Based on the calculation result in 2), measure L h The average temperature rise of the high-voltage winding, the average temperature rise of the low-voltage winding and the sound pressure after the distribution transformer has been running stably for 60 minutes under the load rate are T hh , T lh and H h ; 5) According to the test results of 3) and 4), the short-term overload factor α and the long-term overload factor β are obtained: Where, f is the influencing factor related to the installation environment of the distribution transformer; 6) Evaluate the demand for capacity expansion of distribution transformers based on the capacity expansion assessment factors: Where γ is the fan heat dissipation efficiency evaluation factor, d and g are empirical coefficients related to the insulation structure of the distribution transformer. If γ≤1, it is considered that the distribution transformer does not need to be expanded, otherwise it is considered that it needs to be expanded.

Images