An evaluation method for the capacity expansion requirements of a distribution transformer

Abstract

The present invention discloses an evaluation method for the capacity expansion requirement of a distribution transformer, which includes the following steps: obtaining the nameplate parameters of the distribution transformer and the type test data at the time of factory shipment, obtaining the operating load rate data of the distribution transformer within one year, measuring the average temperature rise of the high-voltage winding and the average temperature rise of the low-voltage winding after stable operation for different times at the maximum operating load rate, measuring 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 at the maximum hourly average load rate, thereby calculating the short-term overload factor and the long-term overload factor, and finally determining the capacity expansion evaluation factor to evaluate the capacity expansion requirement of the distribution transformer. The beneficial effect of the present invention lies in proposing an evaluation method for the capacity expansion requirement of a distribution transformer, which can provide a method for evaluating the service performance of the distribution transformer.

Description

Technical Field

[0001] The present invention belongs to the field of electrical equipment status assessment, and particularly relates to an assessment method for the capacity expansion requirement of a distribution transformer. Background Art

[0002] The power industry is the foundation and lifeblood of the entire national economy. Since the founding of New China, China's power industry has achieved remarkable development, 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. Through it, alternating current electrical energy of one voltage is converted into alternating current electrical energy of another voltage to meet the electricity consumption needs of users. Its safe and stable operation is crucial to the power industry.

[0003] Due to the volatility of power load, the distribution transformer may face heavy overload conditions. Long-term operation under heavy overload conditions may accelerate the reduction of the distribution transformer's lifespan. To ensure the safety and stability of the long-term operation of the distribution transformer, capacity expansion treatment is usually required for distribution transformers that cannot meet the operation requirements of the distribution area. However, there is currently no accurate and rapid judgment method for whether a distribution transformer needs capacity expansion. Therefore, to ensure the long-term safe and stable operation of the distribution transformer, an assessment method for the capacity expansion requirement of the distribution transformer is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to provide an assessment method for the capacity expansion requirement of a distribution transformer, characterized in that the distribution transformer is a three-phase structure, including the following steps:

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

[0006] 2) Obtain the annual operation load rate data of the distribution transformer, including the maximum operation load rate L max , and the maximum hourly average load rate L h :

[0007]

[0008]

[0009] where L(t) is the function of the operation load rate changing with time, t is the time, and the value range is 0 - 525600 min, and i is the intermediate value of the value, ;

[0010] 3) According to the calculation results of 2), measure L maxAfter the distribution transformer operates stably for 15 min, 30 min, 45 min, and 60 min under the load rate, the average temperature rise of the high-voltage winding and the average temperature rise of the low-voltage winding are T hp and T lp , p is the intermediate value of the value, ;

[0011] 4) According to the calculation results in 2), measure L h After the distribution transformer operates stably for 60 min under the load rate, the average temperature rise of the high-voltage winding, the average temperature rise of the low-voltage winding, and the sound pressure are T hh 、T lh and H h ;

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

[0013]

[0014]

[0015] In the formula, f is the influence factor related to the installation environment of the distribution transformer;

[0016] 6) Evaluate the capacity expansion demand of the distribution transformer according to the capacity expansion evaluation factor:

[0017]

[0018] In the formula, γ is the evaluation factor of the fan heat dissipation efficiency, and d and g are the empirical coefficients related to the insulation structure of the distribution transformer. If γ ≤ 1, it is considered that the distribution transformer does not need capacity expansion, otherwise it is considered that capacity expansion is required. Description of the Drawings

[0019] Figure 1 It shows a flowchart for evaluating the capacity expansion demand of a distribution transformer. Detailed Embodiment

[0020] The following further details the implementation process of the present invention in conjunction with the drawings. As Figure 1 The process includes the following steps:

[0021] 1) Obtain the nameplate parameters of the distribution transformer and the type test data at the time of factory, including the rated capacity Q, the average temperature rise of the high-voltage winding in the temperature rise type test T h , the average temperature rise of the low-voltage winding in the temperature rise type test T l , and the sound pressure in the sound level measurement type test H;

[0022] 2) Obtain the operation load rate data of the distribution transformer within one year, including the maximum operation load rate L max , the maximum hourly average load rate L h :

[0023]

[0024]

[0025] Wherein, L(t) is the function of the operating load rate varying with time, t is time, and its value range is 0 - 525600 min, i is an intermediate value for taking values, ;

[0026] 3) According to the calculation results in 2), measure L max The average temperature rises of the high-voltage winding and the low-voltage winding of the distribution transformer after stable operation for 15 min, 30 min, 45 min, and 60 min under the load rate are T hp and T lp , p is an intermediate value for taking values, ;

[0027] 4) According to the calculation results in 2), measure L h The average temperature rises of the high-voltage winding, the low-voltage winding, and the sound pressure of the distribution transformer after stable operation for 60 min under the load rate are T hh 、T lh and H h ;

[0028] 5) According to the test results in 3) and 4), obtain the short-term overload factor α and the long-term overload factor β:

[0029]

[0030]

[0031] Wherein, f is an influence factor related to the installation environment of the distribution transformer;

[0032] 6) Evaluate the capacity expansion requirement of the distribution transformer according to the capacity expansion evaluation factor:

[0033]

[0034] Wherein, γ is the evaluation factor of the fan heat dissipation efficiency, 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 capacity expansion; otherwise, it is considered that capacity expansion is required.

[0035] The beneficial effect of the present invention is to propose an evaluation method for the capacity expansion requirement of a distribution transformer, 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 and factory type test data of the distribution transformer, 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 : ； ； Where L(t) is the function of the load rate changing with time, t is time, the value range is 0-525600 min, i is the intermediate value, ; 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, ; 4) Based on the calculation results 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 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 expansion of distribution transformers based on the 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.

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