CN112072610B - An optimization method and system for circuit breaker failure protection based on comprehensive differential - Google Patents

Abstract

The invention discloses a circuit breaker failure protection optimization method and system based on comprehensive difference, wherein the method includes identifying CT tail current when the circuit breaker is disconnected near the current 90 degrees and the current zero-crossing point; if it is identified as the CT tail current , the control circuit breaker failure protection will return after a delay, and no tripping will occur. The invention can quickly and correctly judge the CT tail, make the circuit breaker failure protection return with a delay, shorten the fault duration after the circuit breaker fails, and reduce the influence on the system stability.

Description

An optimization method and system for circuit breaker failure protection based on comprehensive differential

technical field

The invention relates to the field of power system relay protection, in particular to an optimization method and system for circuit breaker failure protection based on comprehensive differential.

Background technique

Circuit breaker failure protection is a kind of backup protection widely used in relay protection.

With the development of my country's power grid, the electrical distance between each node is getting closer and closer, and the system's requirement for the ultimate fault removal time is getting shorter and shorter. my country's power grid has the characteristics of long distance, large capacity and parallel operation of AC and DC, which leads to more prominent problems. Once the circuit breaker refuses to operate, it will bring great damage to the stability of the system.

SUMMARY OF THE INVENTION

In view of this, the purpose of the embodiments of the present application is to provide an optimization method and system for circuit breaker failure protection based on comprehensive differential, which can quickly and correctly determine CT tailing, delay the return of circuit breaker failure protection, and shorten the circuit breaker. The duration of the fault after the failure reduces the impact on the system stability.

In a first aspect, an embodiment of the present application provides a comprehensive differential-based circuit breaker failure protection optimization method, including:

The cosine criterion and the full cycle criterion are formed into a logical OR, and any action of the cosine criterion and the full cycle criterion will identify the current current as the CT tail current.

If it is identified as CT trailing current, the control circuit breaker failure protection will return after a delay, and no tripping will occur.

In conjunction with the first aspect, the embodiment of the present application provides a first possible implementation of the first aspect, wherein the cosine criterion and the full circumference criterion are formed into a logical OR, and the cosine criterion and the full circumference If any action in the criterion, the current current is identified as CT tail current, including:

If the cosine criterion works, it is judged that the current current is the CT tail current when the circuit breaker is disconnected near the zero-crossing point.

If the full-cycle criterion works, it is judged that the current current is the CT tail current when the circuit breaker is disconnected near 90 degrees.

In conjunction with the first aspect, the embodiment of the present application provides a second possible implementation manner of the first aspect, wherein the calculation method of the cosine criterion is:

Calculate the proportional result of the 2-point cosine difference. When the circuit breaker is disconnected near the zero-crossing point of the current current, the short-term amplitude of the 2-point cosine difference increases, and it is judged as a CT tail current.

Calculating the result of the ratio of the 1-point full-cycle difference, when the current current is near 90 degrees or near the zero-crossing point when the circuit breaker is disconnected, the 1-point full-cycle differential does not have a larger amplitude.

The 2-point cosine differential proportional result and the 1-point full-cycle differential proportional result form a logical AND to form a cosine criterion to identify the CT tail current when the circuit breaker is disconnected near the current zero-crossing point.

In conjunction with the first aspect, the embodiment of the present application provides a third possible implementation manner of the first aspect, wherein the calculation method of the all-round criterion is:

The result of calculating the full-cycle Fourier ratio shows that when the circuit breaker is disconnected near the current current of 90 degrees, the short-term amplitude of the full-cycle Fourier becomes larger, and it is judged as CT tail current.

Calculating the result of the ratio of the 1-point full-cycle difference, when the current current is near 90 degrees or near the zero-crossing point when the circuit breaker is disconnected, the 1-point full-cycle differential does not have a larger amplitude.

The 1-point full-cycle differential ratio result and the full-cycle Fourier ratio result are formed into a logical AND to form a full-cycle criterion to identify the CT tail current when the circuit breaker is disconnected near a current of 90 degrees.

计算全周傅氏的一周前计算结果

按照公式

进行比例运算，识别电流变化趋势，若大于全周傅氏比例门槛，则说明当前电流为断路器断开时的CT拖尾电流，进行全周傅氏动作(所述全周傅氏比例门槛的值为

的值)。In conjunction with the first aspect, the embodiment of the present application provides a fourth possible implementation manner of the first aspect, wherein the calculation method of the Fourier ratio result of the whole week is to calculate the calculation result of the current moment of the Fourier of the whole week

Calculate the result of a week ago for the full week Four

According to the formula

Carry out proportional operation to identify the current change trend, if it is greater than the full-cycle Fourier ratio threshold, it means that the current current is the CT tail current when the circuit breaker is disconnected, and the full-cycle Fourier action is performed (the full-cycle Fourier ratio threshold is value is

value).

计算电流一周前的2点余弦差分计算结果

按照公式

进行比例运算，识别电流变化趋势，若大于2点余弦差分比例门槛，则说明当前电流为断路器断开时的CT拖尾电流，进行2点余弦差分动作(所述2点余弦差分比例门槛的值为MK_cos2的值)。The calculation method of the 2-point cosine difference ratio result is to calculate the 2-point cosine difference calculation result at the current moment of the current.

Calculate the 2-point cosine difference calculation result of the current one week ago

According to the formula

Perform proportional operation to identify the current change trend. If it is greater than the 2-point cosine differential proportional threshold, it means that the current current is the CT trailing current when the circuit breaker is disconnected, and the 2-point cosine differential action is performed (the 2-point cosine differential proportional threshold of the value is the value of MK _cos2 ).

计算电流一周前的1点全周差分计算结果

按照公式

进行比例运算，识别电流变化趋势，若小于1点全周差分比例门槛，则1点全周差分动作(所述1点全周差分比例门槛的值为MK_diff1的值)。The calculation method of the 1-point full-cycle differential ratio result is to calculate the 1-point full-cycle differential calculation result at the current moment of the current.

Calculate the calculation result of the full-cycle difference at 1 point one week before the current

According to the formula

Proportional operation is performed to identify the current change trend. If it is less than the 1-point full-cycle differential ratio threshold, the 1-point full-cycle differential ratio acts (the value of the 1-point full-cycle differential ratio threshold is the value of MK _diff1 ).

In a second aspect, an embodiment of the present application further provides a system for optimizing circuit breaker failure protection based on comprehensive differential, which is used to implement the aforementioned method for optimizing circuit breaker failure protection based on comprehensive differential, including:

The identification device is used to identify the CT tail current when the circuit breaker is disconnected near the current 90 degrees and the current zero-crossing point.

The control device is used to control the circuit breaker failure protection to return with a delay time without tripping when it is identified as CT trailing current.

In conjunction with the second aspect, the embodiment of the present application provides a first possible implementation manner of the second aspect, wherein the identification device includes:

The full-week Fourier calculation module is used to calculate the full-week Fourier ratio result. When the circuit breaker is disconnected near the current current of 90 degrees, the short-term amplitude of the full-week Fourier becomes larger, and it is judged as a CT tail current.

The 2-point cosine difference calculation module is used to calculate the proportional result of the 2-point cosine difference. When the circuit breaker is disconnected near the current zero-crossing point, the short-term amplitude of the 2-point cosine difference increases, and it is judged as a CT tail current.

The 1-point full-cycle differential calculation module is used to calculate the 1-point full-cycle differential ratio result. When the circuit breaker is disconnected near the current current of 90 degrees or near the zero-crossing point, the 1-point full-cycle differential will not increase in amplitude;

The cosine criterion module is used to form a logical AND of the 2-point cosine differential proportional result and the 1-point full-cycle differential proportional result to form a cosine criterion to identify the CT tail current when the circuit breaker is disconnected near the current zero-crossing point.

The full-cycle criterion module is used to form a logical AND of the full-cycle differential ratio result of 1 point and the full-cycle Fourier ratio result to form a full-cycle criterion to identify the CT tail current when the circuit breaker is disconnected near the current of 90 degrees.

In conjunction with the second aspect, the embodiment of the present application provides a second possible implementation manner of the second aspect, wherein the full-week Fourier calculation module includes:

The current moment calculation unit of the full-week Fourier is used to calculate the calculation result of the current moment of the full-week Fourier

The one-week-old calculation unit of the full-week Fourier is used to calculate the one-week previous calculation result of the full-week Four.

进行比例运算，识别电流变化趋势，若大于比例门槛

则全周傅氏动作。Full-week Fourier scale unit, used to follow the formula

Perform proportional operation to identify the current change trend, if it is greater than the proportional threshold

Then the whole Zhou Fu moves.

In conjunction with the second aspect, the embodiments of the present application provide a third possible implementation manner of the second aspect, wherein the 2-point cosine difference calculation module includes:

2-point cosine difference current moment calculation unit, used to calculate the current moment calculation result of 2-point cosine difference

2-point cosine difference calculation unit one week ago, used to calculate the calculation result of 2-point cosine difference one week ago

进行比例运算，识别电流变化趋势，若大于比例门槛MK_cos2，则2点余弦差分动作。2-point cosine difference proportional operation unit, used to follow the formula

Proportional operation is performed to identify the current change trend. If it is greater than the proportional threshold MK _cos2 , the 2-point cosine differential action will be performed.

In conjunction with the second aspect, the embodiment of the present application provides a fourth possible implementation manner of the second aspect, wherein the 1-point full-circle difference calculation module includes:

1-point full-week difference current moment calculation unit, used to calculate the current moment calculation result of 1-point full-week differential

1-point full-week difference calculation unit one week ago, used to calculate the one-week previous calculation result of 1-point full-week difference

进行比例运算，识别电流变化趋势，若小于比例门槛MK_diff1，则1点全周差分动作。1-point full-cycle difference proportional operation unit, used to follow the formula

Perform proportional operation to identify the current change trend. If it is less than the proportional threshold MK _diff1 , then 1-point differential action will occur throughout the cycle.

The beneficial effects of the embodiments of the present invention are:

In the case of CT tailing, the invention can quickly and correctly judge CT tailing according to the different electrical characteristics of 2-point cosine difference, 1-point full-circle difference and full-circle Fourier, so that the circuit breaker failure protection delay is returned and shortened The duration of the fault after the circuit breaker fails to reduce the impact on the system stability. The speed and correctness of CT trailing identification are improved, and the delay of circuit breaker failure protection is optimized.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

A method and system for optimizing circuit breaker failure protection based on comprehensive differential of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Fig. 1 is the flow chart of the circuit breaker failure protection optimization method based on comprehensive difference of the present invention;

Fig. 2 is the logic diagram of the circuit breaker failure protection optimization method based on comprehensive difference of the present invention;

3 is a schematic diagram of the current situation when the CT tailing occurs in the vicinity of 90 degrees of current in the circuit breaker failure protection optimization method based on comprehensive differential of the present invention;

4 is a schematic diagram of the effect of the full-cycle Fourier algorithm when the CT tailing occurs near 90 degrees of the current of the circuit breaker failure protection optimization method based on the comprehensive difference of the present invention;

5 is a schematic diagram of the effect of the 2-point cosine difference algorithm of the circuit breaker failure protection optimization method based on comprehensive difference of the present invention when CT tailing occurs near 90 degrees of current;

6 is a schematic diagram of the effect of the 1-point full-cycle differential algorithm of the circuit breaker failure protection optimization method based on comprehensive differential of the present invention when CT tailing occurs near 90 degrees of current;

7 is a schematic diagram of the current situation when the CT tailing occurs near the current zero-crossing point of the circuit breaker failure protection optimization method based on the comprehensive difference of the present invention;

8 is a schematic diagram of the effect of the full-cycle Fourier algorithm when the CT tailing occurs near the current zero-crossing point of the circuit breaker failure protection optimization method based on the comprehensive difference of the present invention;

9 is a schematic diagram of the effect of the 2-point cosine difference algorithm when the CT tailing occurs near the current zero-crossing point of the circuit breaker failure protection optimization method based on the comprehensive difference of the present invention;

10 is a schematic diagram of the effect of the 1-point full-cycle differential algorithm when the CT tailing occurs near the current zero-crossing point of the circuit breaker failure protection optimization method based on the comprehensive differential of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein can be arranged and designed in a variety of different configurations.

Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The embodiments described below and features in the embodiments may be combined with each other without conflict.

Referring to FIG. 1 to FIG. 10 , in a first aspect, an embodiment of the present application provides a method for optimizing circuit breaker failure protection based on comprehensive differential, including:

S1, the cosine criterion and the whole cycle criterion are formed into a logical OR, and any action of the cosine criterion and the whole cycle criterion will identify the current current as the CT tail current.

S2, if it is identified as CT trailing current, the control circuit breaker failure protection will return after a delay, and no trip will occur.

In conjunction with the first aspect, the embodiment of the present application provides the first possible implementation of the first aspect, wherein the cosine criterion and the full circumference criterion are formed into a logical OR as described in S1, and the cosine criterion and the Any action in the whole cycle criterion will identify the current current as the CT tail current, including:

If the cosine criterion works, it is judged that the current current is the CT tail current when the circuit breaker is disconnected near the zero-crossing point.

If the full-cycle criterion works, it is judged that the current current is the CT tail current when the circuit breaker is disconnected near 90 degrees.

Figures 8 to 10 show the simulation results of the three algorithms when the fault current is trailing near zero-crossing. It can be seen from the figures that in the initial stage of CT trailing, the 2-point cosine difference has a short rising stage, while 1 There is no rising stage in point full-week difference and full-week Fourier.

Figures 4 to 6 show the simulation results of the three algorithms when the fault current is trailing around 90 degrees. It can be seen from the figures that in the initial stage of CT trailing, the Fourier shows a short rising stage in the whole week, while 1 There is no rising stage for the point full-cycle difference and the 2-point cosine difference. In the AC power grid, the circuit breaker will choose to disconnect near the zero-crossing point, so the probability of this situation is low, but for the integrity of the criterion, this criterion is still set.

In order to ensure the correctness of the criterion, generally 2 to 3 points are selected to satisfy the criterion, identified as CT smearing, and used in conjunction with the proportional threshold.

In conjunction with the first aspect, the embodiment of the present application provides a second possible implementation manner of the first aspect, wherein the calculation method of the cosine criterion is:

Calculate the proportional result of the 2-point cosine difference. When the circuit breaker is disconnected near the zero-crossing point of the current current, the short-term amplitude of the 2-point cosine difference increases, and it is judged as a CT tail current.

Calculating the result of the ratio of the 1-point full-cycle difference, when the current current is near 90 degrees or near the zero-crossing point when the circuit breaker is disconnected, the 1-point full-cycle differential does not have a larger amplitude.

The 2-point cosine differential proportional result and the 1-point full-cycle differential proportional result form a logical AND to form a cosine criterion to identify the CT tail current when the circuit breaker is disconnected near the current zero-crossing point.

In conjunction with the first aspect, the embodiment of the present application provides a third possible implementation manner of the first aspect, wherein the calculation method of the all-round criterion is:

The result of calculating the full-cycle Fourier ratio shows that when the circuit breaker is disconnected near the current current of 90 degrees, the short-term amplitude of the full-cycle Fourier becomes larger, and it is judged as CT tail current.

Calculating the result of the ratio of the 1-point full-cycle difference, when the current current is near 90 degrees or near the zero-crossing point when the circuit breaker is disconnected, the 1-point full-cycle differential does not have a larger amplitude.

The 1-point full-cycle differential ratio result and the full-cycle Fourier ratio result are formed into a logical AND to form a full-cycle criterion to identify the CT tail current when the circuit breaker is disconnected near a current of 90 degrees.

In conjunction with the first aspect, the embodiments of the present application provide a fourth possible implementation manner of the first aspect,

计算全周傅氏的一周前计算结果

按照公式

进行比例运算，识别电流变化趋势，若大于全周傅氏比例门槛，则说明当前电流为断路器断开时的CT拖尾电流，进行全周傅氏动作，所述全周傅氏比例门槛的值为

的值。Wherein, the calculation method of the full-week Fourier ratio result is to calculate the current moment calculation result of the full-week Fourier

Calculate the result of a week ago for the full week Four

According to the formula

Perform proportional operation to identify the current change trend. If it is greater than the full-cycle Fourier ratio threshold, it means that the current current is the CT tail current when the circuit breaker is disconnected, and the full-cycle Fourier action is performed. The full-cycle Fourier ratio threshold is value is

value of .

The Fourier coefficient algorithm for the whole week is as follows:

In the formula, N is the number of sampling points of one cycle, n is the sampling number of one cycle, yc is the coefficient of the real part, and ys is the coefficient of the imaginary part.

Calculation of the real and imaginary parts of the whole week Fourier:

In the formula, x _k is the sampling point, re is the real part, and im is the imaginary part.

计算电流一周前的2点余弦差分计算结果

按照公式

进行比例运算，识别电流变化趋势，若大于2点余弦差分比例门槛，则说明当前电流为断路器断开时的CT拖尾电流，进行2点余弦差分动作，所述2点余弦差分比例门槛的值为MK_cos2的值。Wherein, the calculation method of the 2-point cosine difference ratio result is to calculate the 2-point cosine difference calculation result at the current moment of the current

Calculate the 2-point cosine difference calculation result of the current one week ago

According to the formula

Perform proportional operation to identify the current change trend. If it is greater than the 2-point cosine differential proportional threshold, it means that the current current is the CT tail current when the circuit breaker is disconnected, and the 2-point cosine differential action is performed. The 2-point cosine differential proportional threshold is The value is the value of MK _cos2 .

The difference cosine coefficient algorithm for 2-point cosine difference is as follows:

In the formula, dyc ₂ is the cosine coefficient after merging the 2-point difference, and yc is the full-week Fourier real part coefficient.

Substitute the difference cosine coefficient vector dyc ₂ into the sine-modified mann-morrison algorithm, as follows:

In the formula, Mc ₂ is the real part coefficient of the 2-point cosine difference, and Ms ₂ is the imaginary part coefficient of the 2-point cosine difference.

The real and imaginary parts of the 2-point cosine difference are calculated as follows:

In the formula, x(k) is the sampling value, re2 is the real part of the 2-point cosine difference, and im2 is the imaginary part of the 2-point cosine difference.

计算电流一周前的1点全周差分计算结果

按照公式

进行比例运算，识别电流变化趋势，若小于1点全周差分比例门槛，则1点全周差分动作，所述1点全周差分比例门槛的值为MK_diff1的值。The calculation method of the 1-point full-cycle differential ratio result is to calculate the 1-point full-cycle differential calculation result at the current moment of the current.

Calculate the calculation result of the full-cycle difference at 1 point one week before the current

According to the formula

Proportional operation is performed to identify the current change trend. If it is less than the 1-point full-cycle differential ratio threshold, the 1-point full-cycle differential ratio acts. The value of the 1-point full-cycle differential ratio threshold is the value of MK _diff1 .

The difference coefficient algorithm of the 1-point full-cycle difference is as follows:

In the formula, yc is the full-cycle Fourier cosine coefficient, ys is the full-cycle Fourier sine coefficient, dyc1 is the cosine coefficient with difference, and dys1 is the sine coefficient with difference.

The real and imaginary parts of the 1-point difference full-week Fourier are calculated as follows:

In the formula, x(k) is the sampling value, re1 is the real part of the 1-point difference over the whole circumference, and im1 is the imaginary part of the 1-point difference over the whole circumference.

Referring to FIG. 1 to FIG. 10 , in the second aspect, an embodiment of the present application further provides a circuit breaker failure protection optimization system based on comprehensive differential, which is used to implement the aforementioned comprehensive differential-based circuit breaker failure protection optimization method ,include:

The identification device is used to identify the CT tail current when the circuit breaker is disconnected near the current 90 degrees and the current zero-crossing point.

The control device is used to control the circuit breaker failure protection to return with a delay time without tripping when it is identified as CT trailing current.

In conjunction with the second aspect, the embodiment of the present application provides a first possible implementation manner of the second aspect, wherein the identification device includes:

The 2-point cosine difference calculation module is used to calculate the proportional result of the 2-point cosine difference.

The 1-point full-week differential calculation module is used to calculate the 1-point full-week differential ratio result.

The full-week Fourier calculation module is used to calculate the full-week Fourier ratio result.

The cosine criterion module is used to form a logical AND of the 2-point cosine differential proportional result and the 1-point full-cycle differential proportional result to form a cosine criterion to identify the CT tail current when the circuit breaker is disconnected near the current zero-crossing point .

The full-cycle criterion module, which forms a logical AND of the 1-point full-cycle differential ratio result and the full-cycle Fourier ratio result to form a full-cycle criterion to identify the CT trailing current when the circuit breaker is disconnected near the current of 90 degrees .

The CT trailing current identification module forms a logical OR of the cosine criterion and the full cycle criterion, and any action of the cosine criterion and the full cycle criterion is identified as a CT trailing current.

In conjunction with the second aspect, the embodiment of the present application provides a second possible implementation manner of the second aspect, wherein the full-week Fourier calculation module includes:

The current moment calculation unit of the full-week Fourier is used to calculate the calculation result of the current moment of the full-week Fourier

The one-week-old calculation unit of the full-week Fourier is used to calculate the one-week previous calculation result of the full-week Four.

进行比例运算，识别电流变化趋势，若大于比例门槛

则全周傅氏动作。Full-week Fourier scale unit, used to follow the formula

Perform proportional operation to identify the current change trend, if it is greater than the proportional threshold

Then the whole Zhou Fu moves.

In conjunction with the second aspect, the embodiments of the present application provide a third possible implementation manner of the second aspect, wherein the 2-point cosine difference calculation module includes:

2-point cosine difference current moment calculation unit, used to calculate the current moment calculation result of 2-point cosine difference

2-point cosine difference calculation unit one week ago, used to calculate the calculation result of 2-point cosine difference one week ago

进行比例运算，识别电流变化趋势，若大于比例门槛MK_cos2，则2点余弦差分动作。2-point cosine difference proportional operation unit, used to follow the formula

Proportional operation is performed to identify the current change trend. If it is greater than the proportional threshold MK _cos2 , the 2-point cosine differential action will be performed.

In conjunction with the second aspect, the embodiment of the present application provides a fourth possible implementation manner of the second aspect, wherein the 1-point full-circle difference calculation module includes:

1-point full-week difference current moment calculation unit, used to calculate the current moment calculation result of 1-point full-week differential

1-point full-week difference calculation unit one week ago, used to calculate the one-week previous calculation result of 1-point full-week difference

进行比例运算，识别电流变化趋势，若小于比例门槛MK_diff1，则1点全周差分动作。1-point full-cycle difference proportional operation unit, used to follow the formula

Perform proportional operation to identify the current change trend. If it is less than the proportional threshold MK _diff1 , then 1-point differential action will occur throughout the cycle.

The embodiment of the present invention aims to protect a circuit breaker failure protection optimization method and system based on comprehensive differential, and has the following effects:

In the case of CT tailing, the invention can quickly and correctly judge CT tailing according to the different electrical characteristics of 2-point cosine difference, 1-point full-circle difference and full-circle Fourier, so that the circuit breaker failure protection delay is returned and shortened The duration of the fault after the circuit breaker fails to reduce the impact on the system stability. The speed and correctness of CT trailing identification are improved, and the delay of circuit breaker failure protection is optimized.

The computer program product of the method and system for optimization of circuit breaker failure protection based on comprehensive differential provided by the embodiments of the present application includes a computer-readable storage medium storing program codes, and the instructions included in the program codes can be used to execute the above method embodiments. For the specific implementation, reference may be made to the method embodiments, which will not be repeated here.

Specifically, the storage medium can be a general-purpose storage medium, such as a removable disk, a hard disk, etc., when the computer program on the storage medium is run, the above-mentioned method for optimizing circuit breaker failure protection based on comprehensive differential can be executed, so as to be able to quickly and accurately It is judged that the CT is tailing, so that the circuit breaker failure protection delay returns.

The functions, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a processor-executable non-volatile computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes.

Finally, it should be noted that the above-mentioned embodiments are only specific implementations of the present application, and are used to illustrate the technical solutions of the present application, rather than limit them. The embodiments describe the application in detail, and those of ordinary skill in the art should understand that: any person skilled in the art can still modify the technical solutions described in the foregoing embodiments within the technical scope disclosed in the application. Or can easily think of changes, or equivalently replace some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions in the embodiments of the application, and should be covered in this application. within the scope of protection. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (7)

1. a circuit breaker failure protection optimization method based on comprehensive differential, is characterized in that, comprises: The cosine criterion and the whole cycle criterion are formed into a logical OR, and any action in the cosine criterion and the whole cycle criterion identifies that the current current is the CT trailing current; If it is identified as CT trailing current, the control circuit breaker failure protection will return after a delay, and no tripping will occur; The calculation method of the cosine criterion is: Calculate the result of the 2-point cosine difference ratio. When the circuit breaker near the zero-crossing point of the current current is disconnected, the short-term amplitude of the 2-point cosine difference increases, and it is judged as CT tail current; Calculate the result of the ratio of the 1-point full-cycle differential. When the current current is near 90 degrees or near the zero-crossing point when the circuit breaker is disconnected, the 1-point full-cycle differential does not have a larger amplitude; The 2-point cosine differential ratio result and the 1-point full-cycle differential ratio result form a logical AND to form a cosine criterion to identify the CT tail current when the circuit breaker is disconnected near the current zero-crossing point; The calculation method of the whole week criterion is: Calculate the result of the Fourier ratio of the whole week. When the circuit breaker is disconnected near the current current of 90 degrees, the short-term amplitude of the Fourier of the whole week becomes larger, and it is judged as the CT tail current; Calculate the result of the ratio of the 1-point full-cycle differential. When the current current is near 90 degrees or near the zero-crossing point when the circuit breaker is disconnected, the 1-point full-cycle differential does not have a larger amplitude; The 1-point full-cycle differential ratio result and the full-cycle Fourier ratio result are formed into a logical AND to form a full-cycle criterion to identify the CT tail current when the circuit breaker is disconnected near a current of 90 degrees. 2. The circuit breaker failure protection optimization method based on comprehensive difference according to claim 1, characterized in that, the cosine criterion and the full cycle criterion are formed into a logical OR, and the cosine criterion and the full cycle criterion are formed into a logical OR. According to any of the actions, the current current is identified as the CT tail current, including: If the cosine criterion works, it is judged that the current current is the CT tail current when the circuit breaker is disconnected near the zero-crossing point; If the full-cycle criterion works, it is judged that the current current is the CT tail current when the circuit breaker is disconnected near 90 degrees. 3. The circuit breaker failure protection optimization method based on comprehensive difference according to claim 2, wherein the calculation method of the full-week Fourier ratio result is to calculate the current moment calculation result of the full-week Fourier

Calculate the result of a week ago for the full week Four

According to the formula

Perform proportional operation to identify the current change trend. If it is greater than the full-cycle Fourier ratio threshold, it means that the current current is the CT trailing current when the circuit breaker is disconnected, and the full-cycle Fourier action is performed; The calculation method of the 2-point cosine difference ratio result is to calculate the 2-point cosine difference calculation result at the current moment of the current.

Calculate the 2-point cosine difference calculation result of the current one week ago

According to the formula

Perform proportional operation to identify the current change trend. If it is greater than the 2-point cosine differential proportional threshold, it means that the current current is the CT tail current when the circuit breaker is disconnected, and the 2-point cosine differential action is performed; The calculation method of the 1-point full-cycle differential ratio result is to calculate the 1-point full-cycle differential calculation result at the current moment of the current.

Calculate the calculation result of the full-cycle difference at 1 point one week before the current

According to the formula

Perform proportional operation to identify the current change trend. If it is less than the proportional threshold of 1-point full-cycle differential, then 1-point full-cycle differential action. 4. A circuit breaker failure protection optimization system based on comprehensive difference, for realizing the circuit breaker failure protection optimization method based on comprehensive difference according to any one of claims 1 to 3, characterized in that, comprising: The identification device is used to identify that the current current is the CT trailing current, and the cosine criterion and the full-circle criterion are formed into a logical OR, and any action in the cosine criterion and the full-circle criterion, then the current current is the CT trailing current. tail current; The control device is used to control the circuit breaker failure protection to return with a delay when it is identified as CT trailing current without tripping; The identification device includes: The full-week Fourier calculation module is used to calculate the full-week Fourier ratio result. When the circuit breaker is disconnected near the current current of 90 degrees, the short-term amplitude of the full-week Fourier becomes larger, and it is judged as CT tail current; The 2-point cosine difference calculation module is used to calculate the proportional result of the 2-point cosine difference. When the circuit breaker near the zero-crossing point of the current current is disconnected, the short-term amplitude of the 2-point cosine difference increases, and it is judged as a CT tail current; The 1-point full-cycle differential calculation module is used to calculate the 1-point full-cycle differential ratio result. When the circuit breaker is disconnected near the current current of 90 degrees or near the zero-crossing point, the 1-point full-cycle differential will not increase in amplitude; The cosine criterion module is used to form a logical AND of the 2-point cosine differential proportional result and the 1-point full-cycle differential proportional result to form a cosine criterion to identify the CT tail current when the circuit breaker is disconnected near the current zero-crossing point; The full-cycle criterion module is used to form a logical AND of the full-cycle differential ratio result of 1 point and the full-cycle Fourier ratio result to form a full-cycle criterion to identify the CT tail current when the circuit breaker is disconnected near the current of 90 degrees. 5. The circuit breaker failure protection optimization system based on comprehensive differential according to claim 4, wherein the full-cycle Fourier calculation module comprises: The current moment calculation unit of the full-week Fourier is used to calculate the calculation result of the current moment of the full-week Fourier

The one-week-old calculation unit of the full-week Fourier is used to calculate the one-week previous calculation result of the full-week Four.

Full-week Fourier scale unit, used to follow the formula

Proportional operation is performed to identify the current change trend. If it is greater than the value of the full-week Fourier ratio threshold, the full-week Fourier action will be performed. 6. The circuit breaker failure protection optimization system based on comprehensive difference according to claim 4, wherein the 2-point cosine difference calculation module comprises: 2-point cosine difference current moment calculation unit, used to calculate the current moment calculation result of 2-point cosine difference

2-point cosine difference calculation unit one week ago, used to calculate the calculation result of 2-point cosine difference one week ago

2-point cosine difference proportional operation unit, used to follow the formula

Perform proportional operation to identify the current change trend. If it is greater than the value of the 2-point cosine difference proportional threshold, the 2-point cosine difference will act. 7. The circuit breaker failure protection optimization system based on comprehensive differential according to claim 4, wherein the 1-point full-cycle differential calculation module comprises: 1-point full-week difference current moment calculation unit, used to calculate the current moment calculation result of 1-point full-week differential

1-point full-week difference calculation unit one week ago, used to calculate the one-week previous calculation result of 1-point full-week difference

1-point full-cycle difference proportional operation unit, used to follow the formula

Perform proportional operation to identify the current change trend. If it is less than the value of the proportional threshold of the 1-point full-cycle differential, the 1-point full-cycle differential will act.

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