阅读说明：本技术 一种基于载波频率修正的高压设备介质损耗因数计算方法 (High-voltage equipment dielectric loss factor calculation method based on carrier frequency correction ) 是由 吴相贤 张坤勇 杨敏 刘红兵 陈平 于 2019-10-30 设计创作，主要内容包括：本发明涉及一种基于载波频率修正的高压设备介质损耗因数计算方法,本发明将运行设备的线路划分为多个段,然后针对每段分别测量载波频率,再对载波频率进一步处理,消除载波频率的波动误差,最后结合将传统的介质因损耗计算中的参数以载波频率的方式进行更换,从而完成以载波频率作为计算基础,和传统的采用线缆自有参数进行计算相比,本方案考虑了设备的运行状态参数,从而使得测量的结果更为精确。(The invention relates to a high-voltage equipment dielectric loss factor calculation method based on carrier frequency correction, which divides a line of operating equipment into a plurality of sections, then measures carrier frequency for each section respectively, further processes the carrier frequency, eliminates the fluctuation error of the carrier frequency, and finally replaces the parameters in the traditional medium loss calculation in a carrier frequency mode, thereby finishing taking the carrier frequency as a calculation basis.)

1. A high-voltage equipment dielectric loss factor calculation method based on carrier frequency correction is calculated based on carrier frequency in the equipment operation process, and is characterized by comprising the following steps:

s1: during the operation of the measuring equipment, the carrier frequency f of the operation line in each interval l length is measured_cnWherein n represents the nth section of line;

s2: repeated multiple measurements of the carrier frequency f in each l-length operating line_cnAnd has the following components:

in the formula (1), k represents the number of measurements in each section of line l,

s3: the dielectric loss factor calculation formula is as follows:

assuming a dielectric loss of W per unit length_d(W/cm) is W_d＝U²ωCtanδ (3)；

In the formula (3), C represents the capacitance (F/cm) of the line per unit length;

s4: from equations (2) and (3), it follows:

since the heating loss of the line after the device has been operated stably will depend on the resistance value and the leakage current of the line, there are:

r in the formula (5) is a resistance value in the test circuit;

s5: combining equation (5) and equation (4) yields:

in the formula (6), K is a cable correction coefficient, and after a plurality of tests, K is 1.25;

since U ═ IR, equation (6) can be modified to

S6: since ω is 2 pi f, in combination with equation (7),

s7: combining equation (1) and equation (8) yields:

2. the method for calculating the dielectric loss factor of the high-voltage equipment based on the carrier frequency correction as claimed in claim 1, wherein the values of n and k are the same and are greater than or equal to 10.

3. The carrier frequency correction-based high-voltage equipment dielectric loss factor calculation method according to claim 2, wherein the unit of l is cm.

4. The method for calculating dielectric loss factor of high-voltage equipment based on carrier frequency correction according to claim 3, wherein in step S2, carrier frequency f is measured every time_cnIs greater than or equal to

Technical Field

The invention relates to the field of dielectric loss, in particular to a high-voltage equipment dielectric loss factor calculation method based on carrier frequency correction.

Background

Mass loss is energy loss caused by the hysteresis effect of dielectric conductance and dielectric polarization in the insulating material under the action of an electric field. Also called medium loss, abbreviated as medium loss. Under the action of the alternating electric field, a complementary angle delta of an included angle (power factor angle phi) between a current phasor and a voltage phasor flowing in the dielectric medium is called a dielectric loss angle. The dielectric medium has heating phenomenon inside under the action of external electric field, which means that part of electric energy is converted into heat energy to be dissipated, and the energy consumed by the dielectric medium in unit time due to heating under the action of the electric field is called dielectric medium power loss (or dielectric losses for short). Dielectric loss is one of the important quality indicators for dielectrics used in alternating electric fields. The dielectric loss not only consumes electric energy, but also causes the element to generate heat to influence the normal operation of the element. If the dielectric loss is large, it may even cause overheating of the medium to cause dielectric breakdown, so in this sense, the smaller the dielectric loss is, the better. Under the action of a constant electric field, the power of dielectric loss is as follows:

W＝U/R＝(Ed)S/ρd＝σESd

the dielectric loss per unit volume is defined as the dielectric loss ratio:

ω＝σE

under the action of the alternating electric field, the electric displacement D and the electric field strength E both become complex vectors, and the dielectric constant also becomes complex, and the imaginary part of the complex vectors represents the energy loss in the dielectric medium.

From a circuit point of view, the current density in the dielectric is:

J＝dD/dt＝d(εE)/dt＝Jτ+iJe

where J τ is in phase with E. Known as active current density, resulting in energy loss; je, 90 ° advanced compared to E, is called reactive current density.

Definition tan δ ═ J τ/Je ═ epsilon "/epsilon ″', a

In the formula, δ is referred to as a loss angle, tan δ is referred to as a loss tangent, and a dielectric loss factor (dielectriclosfactor) is a parameter for measuring a degree of dielectric loss. The loss tangent, which represents the amount of energy consumed to obtain a given stored charge, is an important evaluation parameter when the dielectric is used as an insulating material. In order to reduce dielectric loss, it is desirable that the material have a smaller dielectric constant and a smaller loss tangent. The reciprocal Q of the loss factor (tan δ) is called the quality factor of the dielectric under the condition of high frequency insulation application, and its value is desirably high.

At present, there are various methods for measuring the dielectric loss factor, which are generally based on the equipment itself, but the dielectric loss changes due to the influence of various operating parameters, especially the influence of carrier frequency, during the use process, so how to determine the dielectric loss factor in the equipment operation process is an important way for accurately measuring the dielectric loss.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a high-voltage equipment dielectric loss factor calculation method based on carrier frequency correction.

The purpose of the invention is realized by the following technical scheme:

a high-voltage equipment dielectric loss factor calculation method based on carrier frequency correction is calculated based on carrier frequency in the equipment operation process, and the method comprises the following steps:

s1: during the operation of the measuring equipment, the carrier frequency f of the operation line in each interval l length is measured_cnWherein n represents the nth section of line;

s2: repeated multiple measurements of the carrier frequency f in each l-length operating line_cnAnd has the following components:

in the formula (1), k represents the number of measurements in each section of line l,

the average value of k represents the number of times of measurement in the nth line;

s3: the dielectric loss factor calculation formula is as follows:

assuming a dielectric loss of W per unit length_d(W/cm)Then there is W_d＝U²ωCtanδ (3)；

In the formula (3), C represents the capacitance (F/cm) of the line per unit length;

s4: from equations (2) and (3), it follows:

since the heating loss of the line after the device has been operated stably will depend on the resistance value and the leakage current of the line, there are:

r in the formula (5) is a resistance value in the test circuit;

s5: combining equation (5) and equation (4) yields:

in the formula (6), K is a cable correction coefficient, and after a plurality of tests, K is 1.25;

since U ═ IR, equation (6) can be modified to

S6: since ω is 2 pi f, in combination with equation (7),

s7: combining equation (1) and equation (8) yields:

compared with the traditional measurement mode, the carrier frequency of the equipment running state is used as the reference parameter for analysis and calculation, and the carrier frequency is more stable in the running process compared with other parameters, so that the dielectric loss calculated based on the carrier frequency is more accurate.

Further, the values of n and k are the same and are more than or equal to 10. The larger the value is, the higher the accuracy of the final measurement is.

Further, the unit of l is cm.

Further, the carrier frequency f is measured each time in the step S2_cnIs greater than or equal to

The invention has the beneficial effects that: the invention divides the line of the operating equipment into a plurality of sections, then measures the carrier frequency for each section, further processes the carrier frequency, eliminates the fluctuation error of the carrier frequency, finally replaces the parameters in the traditional medium loss calculation in the mode of the carrier frequency, thereby finishing taking the carrier frequency as the calculation basis.

Detailed Description

The technical solutions of the present invention are described in further detail below with reference to examples, but the scope of the present invention is not limited to the following.

A high-voltage equipment dielectric loss factor calculation method based on carrier frequency correction is calculated based on carrier frequency in the equipment operation process, and the method comprises the following steps:

s1: during the operation of the measuring equipment, the carrier frequency f of the operation line in each interval l length is measured_cnWherein n represents the nth section of line;

s2: repeated multiple measurements of the carrier frequency f in each l-length operating line_cnAnd has the following components:

in the formula (1), k represents the number of measurements in each section of line l,the average value of k represents the number of times of measurement in the nth line;

s3: the dielectric loss factor calculation formula is as follows:

assuming a dielectric loss of W per unit length_d(W/cm) is W_d＝U²ωCtanδ (3)；

In the formula (3), C represents the capacitance (F/cm) of the line per unit length;

s4: from equations (2) and (3), it follows:

since the heating loss of the line after the device has been operated stably will depend on the resistance value and the leakage current of the line, there are:

r in the formula (5) is a resistance value in the test circuit;

s5: combining equation (5) and equation (4) yields:

in the formula (6), K is a cable correction coefficient, and after a plurality of tests, K is 1.25;

since U ═ IR, equation (6) can be modified to

S6: since ω is 2 pi f, in combination with equation (7),

s7: combining equation (1) and equation (8) yields:

n and k have the same value and are more than or equal to 10, the unit of l is cm, and the carrier frequency f is measured in step S2 every time_cnIs greater than or equal to

The foregoing is merely a preferred embodiment of the invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not intended to be exhaustive or to limit the invention to other embodiments, and to various other combinations, modifications, and environments and may be modified within the scope of the inventive concept as described herein by the teachings or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.