A method for measuring heat dissipation index and dynamically increasing capacity

Abstract

The present invention discloses a method for measuring a heat dissipation index and dynamically increasing the capacity. The heat dissipation index is measured through a heat dissipation test body, and includes the following steps: a. measuring the heat capacity C of the heat dissipation test body; b. heating the heat dissipation test body to a certain temperature T, and the temperature T is used as the initial temperature; c. measuring the corresponding temperature change value ΔT within a certain period of time, and the corresponding time t, and recording them; d. calculating the heat value Q released by the heat dissipation test body within the temperature difference according to the heat capacity C of the heat dissipation test body, Q=C*(ΔT); e. calculating the ratio K of the heat value Q to the surface area s of the heat dissipation test body and the required time t, K=Q / (s*t), and the ratio K is the heat released per unit area per unit time of the heat dissipation test body, which is called the heat dissipation index. The present invention uses the measured heat dissipation index for dynamic capacity increase of line conductors, which has significant effect, high stability, convenient measurement, good real-time performance, and low implementation difficulty.

Description

Technical Field

[0001] The present invention relates to the electric power field, and in particular to a heat dissipation index measurement and dynamic capacity increase method. Background Art

[0002] With the growth of electricity load, some heavily loaded power lines in the power grid have become obvious transmission bottlenecks. Dynamic capacity expansion to tap the transmission potential of existing lines is of great significance to alleviating the pressure on urban power supply.

[0003] At present, the maximum allowable current carrying capacity of conductors is generally calculated in a steady state, which is not suitable for calculating dynamic loads. Moreover, the current carrying capacity of conductors is determined in the design stage. Due to the complexity and uncertainty of the heat transfer environment of conductors, designers usually make the most unfavorable heat dissipation assumption to obtain a sufficiently safe current value. The dispatching department will use this value during the life cycle of the conductor. This has caused the problem that the current carrying capacity of conductors is generally too conservative and has large errors, which cannot give full play to the transmission capacity of the conductors.

[0004] The existing technology indirectly calculates and estimates the real-time dynamic current carrying capacity of the conductor by measuring many parameters such as ambient temperature, sunshine, wind speed, humidity, etc., which involves many sensors and has the disadvantage of large measurement and prediction deviations. Some technologies also measure the temperature of the conductor or the tension of the conductor to estimate the dynamic capacity expansion capacity of the conductor, which involves installing sensors on the conductor and is difficult to install and implement on site. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for measuring and dynamically increasing the heat dissipation index, which has the advantages of convenient measurement, good real-time performance, significant effect, high stability and low implementation difficulty.

[0006] The technical solution of the present invention is as follows: A method for measuring a heat dissipation index is performed by using a heat dissipation test body, comprising the following steps:

[0007] a. measuring the heat capacity C of the heat dissipation test body;

[0008] b. heating the heat dissipation test body to a certain temperature T, which is used as the initial temperature;

[0009] c. Measure the corresponding temperature change value ΔT within a certain period of time and the corresponding time t, and record them;

[0010] d. Calculate the heat value Q released by the heat dissipation test body within the change temperature value ΔT according to the heat capacity C of the heat dissipation test body, where Q=C*(ΔT);

[0011] e. Calculate the ratio K of the calorific value Q to the surface area s of the heat dissipation test body and the required time t, K=Q / (s*t). The ratio K is the heat released per unit area per unit time of the heat dissipation test body at the temperature T, which is called the heat dissipation index.

[0012] Wherein, the heat dissipation test body is a sphere or a cylinder.

[0013] Wherein, the heat dissipation test body is made of aluminum, copper or polymer material.

[0014] Wherein, the internal material of the heat dissipation test body is aluminum, copper, water or oil.

[0015] Optionally, in step b, the heating method of the heat dissipation test body includes heating with a built-in resistance heating wire, heating in a temperature chamber, wrapping heating, circulating medium heating or light wave heating.

[0016] Optionally, in step c, the measured temperature value is measured by a contact temperature measurement method.

[0017] Optionally, in step c, the measured temperature value is measured by a non-contact temperature measurement method.

[0018] A dynamic capacity expansion method based on a heat dissipation index comprises the following steps:

[0019] a. Under the same environment, manufacture a heat dissipation test body according to the material of the conductor of the circuit under test;

[0020] b. measuring the heat K released per unit area per unit time at temperature T of the heat dissipation test body, where the heat K is the heat dissipation index;

[0021] c. Calculate the heat P generated by the conductor of the measured line at the temperature T according to the total area S of the conductor of the measured line, where P=K*S;

[0022] d. Calculate the resistance value R of the measured line conductor at the temperature T, P=I^2*R, and the current I is the maximum current carrying capacity that the measured line conductor can withstand under the environment of the temperature T.

[0023] In step c, the temperature T is higher than the ambient temperature.

[0024] Compared with the prior art, the beneficial effect of the present invention is that the present invention measures the heat dissipation index through a heat dissipation test body made of the same material as the line conductor under test, and then calculates the maximum current carrying capacity that the line conductor under test can withstand under the environment through the obtained heat dissipation index. The measurement method is convenient, simple, and has good real-time performance, and has the advantages of significant effect, high stability, and low implementation difficulty. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with specific embodiments.

[0026] Embodiment 1

[0027] This embodiment provides a method for measuring a heat dissipation index. The method for measuring a heat dissipation index is performed through a heat dissipation test body, and includes the following steps:

[0028] a. measuring the heat capacity C of the heat dissipation test body;

[0029] The heat dissipation test body may be a sphere or a cylinder, and its mass may be measured directly or by first measuring the volume and then calculating it based on the density of the heat dissipation test body;

[0030] b. heating the heat dissipation test body to a certain temperature T, which is used as the initial temperature;

[0031] The heating methods of the heat dissipation test body include heating with built-in resistance heating wire, heating in a temperature chamber, wrapping heating, circulating medium heating or light wave heating;

[0032] c. Measure the corresponding temperature change value ΔT within a certain period of time and the corresponding time t, and record them;

[0033] ΔT = initial temperature - measured temperature;

[0034] During implementation, the measured temperature value can be measured by a contact temperature measurement method or a non-contact temperature measurement method;

[0035] d. Calculate the heat value Q released by the heat dissipation test body within the temperature difference according to the heat capacity C of the heat dissipation test body, where Q=C*(ΔT);

[0036] e. Calculate the ratio K of the calorific value Q to the surface area s of the heat dissipation test body and the required time t, K=Q / (s*t). The ratio K is the heat released per unit area per unit time of the heat dissipation test body at the temperature T, which is called the heat dissipation index.

[0037] The heat dissipation index obtained in this embodiment can be used for dynamic capacity expansion of line conductors. Since the common material of line conductors is aluminum, during measurement, the surface material of the heat dissipation test body is also selected to be aluminum. Of course, copper or other materials can also be selected. The internal material of the heat dissipation test body can be aluminum, copper, water or oil. The dynamic capacity expansion method thereof refers to Example 2.

[0038] Embodiment 2

[0039] This embodiment provides a dynamic capacity expansion method based on a heat dissipation index, which includes the following steps:

[0040] a. Under the same environment, manufacture a heat dissipation test body according to the material of the conductor of the circuit under test;

[0041] b. measuring the heat K released per unit area per unit time at temperature T of the heat dissipation test body, where K is the heat dissipation index;

[0042] c. Calculate the heat dissipation power P of the measured line conductor at the measured temperature T according to the total area S of the measured line conductor, where P=K*S;

[0043] d. Calculate the resistance value R of the measured line conductor at the measuring temperature T. When the heat dissipation power is equal to the heating power, the temperature equilibrium is reached, P=I^2*R. The current I is the maximum current carrying capacity that the measured line conductor can withstand under the environment at the temperature T.

[0044] Since the common line conductor material is aluminum, the material of the heat dissipation test body is also selected to be aluminum. The heat dissipation index is measured by the heat dissipation test body, and then the maximum current carrying capacity that the tested line conductor can withstand in this environment is calculated based on the obtained heat dissipation index, wherein the temperature T is higher than the ambient temperature.

[0045] In summary, the heat dissipation index measurement and dynamic capacity expansion method of the present invention is convenient, simple, and has good real-time performance, and has the advantages of significant effect and high stability.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dynamic capacity expansion method based on heat dissipation index measurement, which is measured by a heat dissipation test body, characterized in that: The following steps are involved: (1) Under the same environment, manufacture a heat dissipation test body according to the material of the conductor of the circuit under test; (2) measuring the heat K released per unit area per unit time at temperature T of the heat dissipation test body, where K is the heat dissipation index; (3) Calculate the heat dissipation power P of the measured line conductor at the measurement temperature T according to the total area S of the measured line conductor, where P=K*S; (4) Calculate the resistance value R of the conductor of the measured line at the temperature T. When the heat dissipation power is equal to the heating power, the temperature equilibrium is reached, P = I^2*R, and the current I is the maximum current carrying capacity that the conductor of the measured line can withstand under the environment of the temperature T; The K is obtained by the following steps: a. measuring the heat capacity C of the heat dissipation test body; b. heating the heat dissipation test body to a certain temperature T, which is used as the initial temperature; c. Measure the corresponding temperature change value ΔT within a certain period of time and the corresponding time t, and record them; d. Calculate the heat value Q released by the heat dissipation test body within the change temperature value ΔT according to the heat capacity C of the heat dissipation test body, where Q=C*(ΔT); e. Calculate the ratio K of the calorific value Q to the surface area s of the heat dissipation test body and the required time t, K=Q / (s*t). The ratio K is the heat released per unit area per unit time of the heat dissipation test body at the temperature T, which is called the heat dissipation index.

2. The method for dynamic capacity expansion based on heat dissipation index measurement according to claim 1, characterized in that: The heat dissipation test body is a sphere or a cylinder.

3. A dynamic capacity expansion method based on heat dissipation index measurement according to claim 1 or 2, characterized in that: The surface material of the heat dissipation test body is aluminum, copper or polymer material.

4. The method for dynamic capacity expansion based on heat dissipation index measurement according to claim 3, characterized in that: The internal material of the heat dissipation test body is aluminum, copper, water or oil.

5. The method for dynamic capacity expansion based on heat dissipation index measurement according to claim 1, characterized in that: In step b, the heating method of the heat dissipation test body includes heating with a built-in resistance heating wire, heating in a temperature box, wrapping heating, circulating medium heating or light wave heating.

6. The method for dynamic capacity expansion based on heat dissipation index measurement according to claim 1, characterized in that: In step c, the temperature value is measured by a contact temperature measurement method.

7. The method for dynamic capacity expansion based on heat dissipation index measurement according to claim 1, characterized in that: In step c, the temperature value is measured by a non-contact temperature measurement method.

8. The method for dynamic capacity expansion based on heat dissipation index measurement according to claim 1, characterized in that: In step c, the temperature T is higher than the ambient temperature.