Arcing angle reliability evaluation method and system

Abstract

The invention provides an arcing angle reliability assessment method and system, belonging to the field of power system insulation protection. The method comprises: based on the arcing angle gap distance, in combination with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage, constructing the operating impulse discharge voltage probability density and the lightning impulse discharge voltage probability density of the arcing angle; calculating the lightning impulse 50% discharge voltage of the insulator string according to the length of the insulator string; calculating the lightning impulse breakdown junction voltage value; calculating the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage, and obtaining reliability assessment parameters; the invention avoids a series of test methods, and is simple to operate and easy to implement.

Description

Technical Field

[0001] The present invention belongs to the field of insulation protection of power systems, and more specifically, relates to an arcing angle reliability assessment method and system. Background Art

[0002] In the DC transmission lines of the power system, since DC current is not easy to extinguish the arc, it is easy to cause insulator aging or even string loss when a lightning strike occurs. Therefore, the arcing angle is widely used in the insulator protection of the grounding electrode in the DC converter station.

[0003] In order to realize the protection of the arcing angle for the insulator, the arcing angle needs to be insulated with the insulator to a certain extent. Usually, in the study of the arcing angle of the insulator string parallel connection of the UHV line, it is believed that the grounding pole line is not in operation for a long time. Therefore, when conducting insulation design and investigation, reference is made to previous engineering experience. In the design stage, the number of insulator strings is matched with the gap distance of the arcing angle used to ensure that the arcing angle discharges before the insulator string; in the verification stage, the reliability of insulation coordination is determined based on repeated experimental studies. Therefore, due to the seldom sufficient demonstration in the design stage, there is no definite understanding of the probability of fault occurrence under actual operation; and the use of repeated experimental studies in the verification stage is not only cumbersome to operate, but also time-consuming and labor-intensive, and the research efficiency is low. The problems existing in the prior art are all due to insufficient research on the reliability of the existing arcing angle and insulator coordination in actual operation, resulting in problems such as insulation mismatch and low lightning resistance in the arcing angle installation line. This not only affects the continuous play of the transmission benefits of the DC system, but also may bring hidden dangers to the safe and reliable operation of the power system. In addition, since the arcing angle is in the actual operating system line, in addition to being compatible with the insulator, it should also complete a certain insulation coordination with the system line to avoid gap discharge under lower overvoltage and reduce the insulation level of the transmission line. Summary of the invention

[0004] In view of the defects of the prior art and taking into account the coordination of the arcing angle, insulators and system lines, the purpose of the present invention is to provide a method and system for evaluating the reliability of the arcing angle, aiming to solve the problem that the existing experimental research based on the arcing angle to determine the reliability of the insulation coordination of the system lines and insulator strings is cumbersome, time-consuming and labor-intensive, and the reliability demonstration is completed in the design stage.

[0005] To achieve the above object, on the one hand, the present invention provides a method for evaluating the reliability of an arcing angle, comprising the following steps:

[0006] Calculate the 50% discharge voltage of the arcing angle based on the arcing angle gap distance;

[0007] Based on the impulse 50% discharge voltage of the arcing angle, combined with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage, the probability density of the operating impulse discharge voltage of the arcing angle and the probability density of the lightning impulse discharge voltage are constructed;

[0008] Calculate the 50% lightning impulse discharge voltage of the insulator string according to the length of the insulator string, and collect the maximum operating voltage of the system line;

[0009] Add the 50% discharge voltage of the arcing angle and the 50% discharge voltage of the lightning impulse of the insulator string and divide by 2 to calculate the voltage value of the lightning impulse breakdown junction point;

[0010] The probability density distribution of the operating impulse discharge voltage of the arcing angle is normalized so that the 50% impulse discharge voltage of the arcing angle is 0;

[0011] The upper system line maximum operating voltage quantile of the probability density distribution of the operating impulse discharge voltage of the normalized arcing angle and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage are calculated to obtain reliability assessment parameters.

[0012] Further preferably, the 50% discharge voltage of the arcing angle is:

[0013] U z =550 d +80

[0014] in, d is the arcing angle gap distance; U z It is the 50% discharge voltage of the arcing angle.

[0015] Further preferably, the lightning impulse 50% discharge voltage of the insulator string is:

[0016] U j =553 l +110

[0017] in, l is the insulator string length; U j It is the 50% discharge voltage of the lightning impulse of the insulator string.

[0018] Further preferably, the reliability evaluation parameters are:

[0019] K =(1- A ) X

[0020] in,K Parameters for reliability assessment; A is the voltage value quantile of the upper lightning impulse breakdown junction point of the probability density distribution of the lightning impulse discharge voltage; X It is the upper system line maximum operating voltage quantile of the probability density distribution of the operating impulse discharge voltage of the arcing angle.

[0021] In another aspect, the present invention provides an arcing angle reliability assessment system, comprising:

[0022] An arcing angle impulse discharge voltage calculation module is used to calculate the arcing angle impulse 50% discharge voltage based on the arcing angle gap distance;

[0023] An impulse discharge voltage probability density construction module is used to construct the probability density of the operating impulse discharge voltage of the arcing angle and the probability density of the lightning impulse discharge voltage based on the impulse 50% discharge voltage of the arcing angle, combined with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage;

[0024] An insulator string lightning impulse discharge voltage calculation module is used to calculate the lightning impulse 50% discharge voltage of the insulator string according to the length of the insulator string;

[0025] Data acquisition module, used to collect the maximum operating voltage of the system circuit;

[0026] A lightning impulse breakdown junction voltage calculation module is used to calculate the voltage value of the lightning impulse breakdown junction point by adding the impulse 50% discharge voltage of the arcing angle and the lightning impulse 50% discharge voltage of the insulator string and dividing the sum by 2;

[0027] A coordinate normalization processing module is used to normalize the probability density distribution of the operation impulse discharge voltage of the arcing angle so that the impulse 50% discharge voltage of the arcing angle is 0;

[0028] The reliability evaluation parameter calculation module is used to calculate the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle after normalization and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage to obtain reliability evaluation parameters.

[0029] Further preferably, the 50% discharge voltage of the arcing angle is:

[0030] U z =550 d +80

[0031] in, d is the arcing angle gap distance; Uz It is the 50% discharge voltage of the arcing angle.

[0032] Further preferably, the lightning impulse 50% discharge voltage of the insulator string is:

[0033] U j =553 l +110

[0034] in, l is the insulator string length; U j It is the 50% discharge voltage of the lightning impulse of the insulator string.

[0035] Further preferably, the reliability evaluation parameters are:

[0036] K =(1- A ) X

[0037] in, K Parameters for reliability assessment; A is the voltage value quantile of the upper lightning impulse breakdown junction point of the probability density distribution of the lightning impulse discharge voltage; X is the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle.

[0038] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art:

[0039] The reliability evaluation parameters calculated by the present invention are based on the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle and the upper lightning impulse breakdown junction voltage quantile of the probability density distribution of the lightning impulse discharge voltage; and the acquisition of the upper lightning impulse breakdown junction voltage quantile of the probability density distribution of the lightning impulse discharge voltage is strongly related to the gap distance between the insulator string and the arcing angle, and the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage is strongly related to the maximum operating overvoltage of the system line. Therefore, the reliability evaluation parameters provided by the present invention comprehensively consider the relationship between the insulator string, the arcing angle and the system line; ensure that under normal circumstances, the insulator string is non-conductive, while the system line is conductive; and can effectively evaluate the reliability of the arcing angle setting scheme.

[0040] The arcing angle reliability assessment method provided by the present invention avoids the selection of a series of experimental methods by defining the gap distance range of the arcing angle, is simple to operate and easy to implement, and overcomes the problems of the prior art of determining the reliability of the arcing angle for the insulation coordination of the system line and the insulator string based on experimental research, which is cumbersome to operate and time-consuming and labor-intensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flow chart of an arcing angle reliability assessment method provided by an embodiment of the present invention;

[0042] Figure 2 2 is a schematic diagram of reliability judgment of operation impact of an arcing angle provided by an embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of lightning impulse reliability judgment of arcing angle provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] In one aspect, the present invention provides a method for evaluating arcing angle reliability, comprising the following steps:

[0046] Calculate the 50% discharge voltage of the arcing angle based on the arcing angle gap distance;

[0047] Based on the impulse 50% discharge voltage of the arcing angle, combined with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage, the probability density of the operating impulse discharge voltage of the arcing angle and the probability density of the lightning impulse discharge voltage are constructed;

[0048] Calculate the 50% lightning impulse discharge voltage of the insulator string according to the length of the insulator string, and collect the maximum operating voltage of the system line;

[0049] Add the 50% discharge voltage of the arcing angle and the 50% discharge voltage of the insulator string lightning impulse and divide by 2 to calculate the voltage value of the lightning impulse breakdown junction point;

[0050] The probability density distribution of the operating impulse discharge voltage of the arcing angle is normalized so that the 50% impulse discharge voltage of the arcing angle is 0;

[0051] The upper system line maximum operating voltage quantile of the probability density distribution of the operating impulse discharge voltage after normalization of the arcing angle and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage are calculated to obtain reliability assessment parameters.

[0052] Further preferably, the 50% discharge voltage of the arcing angle is:

[0053] U z =550 d +80

[0054] in, d is the arcing angle gap distance; U z It is the 50% discharge voltage of the arcing angle.

[0055] Further preferably, the lightning impulse 50% discharge voltage of the insulator string is:

[0056] U j =553 l +110

[0057] in, l is the insulator string length; U j It is the 50% discharge voltage of the lightning impulse of the insulator string.

[0058] Further preferably, the reliability evaluation parameters are:

[0059] K =(1- A ) X

[0060] in, K Parameters for reliability assessment; A is the voltage value quantile of the upper lightning impulse breakdown junction point of the probability density distribution of the lightning impulse discharge voltage; X is the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle.

[0061] In another aspect, the present invention provides an arcing angle reliability assessment system, comprising:

[0062] An arcing angle impulse discharge voltage calculation module is used to calculate the arcing angle impulse 50% discharge voltage based on the arcing angle gap distance;

[0063] An impulse discharge voltage probability density construction module is used to construct the probability density of the operating impulse discharge voltage of the arcing angle and the probability density of the lightning impulse discharge voltage based on the impulse 50% discharge voltage of the arcing angle, combined with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage;

[0064] An insulator string lightning impulse discharge voltage calculation module is used to calculate the 50% lightning impulse discharge voltage of the insulator string according to the length of the insulator string;

[0065] Data acquisition module, used to collect the maximum operating voltage of the system circuit;

[0066] A lightning impulse breakdown junction voltage calculation module is used to calculate the voltage value of the lightning impulse breakdown junction point by adding the impulse 50% discharge voltage of the arcing angle and the lightning impulse 50% discharge voltage of the insulator string and dividing the sum by 2;

[0067] A coordinate normalization processing module is used to normalize the probability density distribution of the operation impulse discharge voltage of the arcing angle so that the impulse 50% discharge voltage of the arcing angle is 0;

[0068] The reliability evaluation parameter calculation module is used to calculate the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle after normalization and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage to obtain reliability evaluation parameters.

[0069] Further preferably, the 50% discharge voltage of the arcing angle is:

[0070] U z =550 d +80

[0071] in, d is the arcing angle gap distance; U z It is the 50% discharge voltage of the arcing angle.

[0072] Further preferably, the lightning impulse 50% discharge voltage of the insulator string is:

[0073] U j =553 l +110

[0074] in, l is the insulator string length; U j It is the 50% discharge voltage of the lightning impulse of the insulator string.

[0075] Further preferably, the reliability evaluation parameters are:

[0076] K =(1- A ) X

[0077] in, K Parameters for reliability assessment; A is the voltage value quantile of the upper lightning impulse breakdown junction point of the probability density distribution of the lightning impulse discharge voltage; X is the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle.

[0078] Example

[0079] Figure 1 A method for evaluating arcing angle reliability provided by an embodiment of the present invention comprises the following steps:

[0080] S1: Obtain the impulse discharge probability density function of the arcing angle;

[0081] The specific steps include:

[0082] S1.1 As Figure 2 As shown, the arcing angle gap distance d is used to calculate the 50% discharge voltage of the arcing angle. U z ;

[0083] The grounding pole line of a converter station of a ±800kV DC transmission project is taken as the research object. The grounding pole line insulator adopts XZP-160 DC disc insulator, the arcing angle gap distance d=1500mm, and the standard deviation of the probability density of the air gap lightning impulse discharge voltage of the insulator string and the arcing angle is σ 1 is taken as 3%, the standard deviation of the probability density of the air gap switching impulse discharge voltage of the insulator string and the arcing angle σ 2 is taken as 5%, then the arcing angle impulse 50% discharge voltage U z for:

[0084] U z =550 d +80=905 (kV)

[0085] S1.2 Calculate the probability density P1 of the switching impulse discharge voltage and the probability density P2 of the lightning impulse discharge voltage at the arcing angle;

[0086] The probability density of the operating impulse discharge voltage of the arcing angle P1~N (905, 5% 2 ), the probability density of lightning impulse discharge voltage at the arcing angle P2~N (905, 3%2 );

[0087] S2: Acquiring the operation impulse related parameters of the system line and the lightning impulse related parameters of the insulator string; specifically comprising the following steps:

[0088] Get the length of the insulator string l ;

[0089] like Figure 2 As shown, the maximum operating voltage of the system line is obtained U x ;

[0090] Obtaining the 50% discharge voltage of the lightning impulse of the insulator string U j ;

[0091] Insulator string length l =1870mm, maximum operating overvoltage value of the system line U x =715kV, 50% discharge voltage of lightning impulse of insulator string U j for:

[0092] U j =553 l +110=1144 (kV)

[0093] S3: Determine the arcing angle operation impulse reliability parameter and the lightning impulse reliability parameter; specifically includes the following steps:

[0094] S3.1: If Figure 3 As shown, the voltage value of the lightning impulse breakdown junction point is calculated U a ;

[0095] U a =( U z + U j ) / 2=1024.5 (kV)

[0096] S3.2: Calculate the upper bound of the P1 distribution U x Quantile X and P2 distribution U a Quantile A ;

[0097] A = P 2 ( U > Ua )

[0098] X = P 1( U > U x )

[0099] in, U is the horizontal coordinate of P1 and P2;

[0100] According to the obtained probability distribution parameters, we can get:

[0101] X ≥99.8%

[0102] A ≤0.2%

[0103] S4: Determine the comprehensive reliability parameters of the arcing angle;

[0104] According to the obtained distribution parameters, calculate the reliability evaluation parameters K for:

[0105] K =(1- A ) X ≥99.6%

[0106] From the reliability parameters obtained above, it can be seen that the selected arcing angle has high reliability and can better achieve insulation coordination with the system line and insulators.

[0107] Compared with the prior art, the present invention has the following advantages:

[0108] The reliability evaluation parameters calculated by the present invention are based on the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle and the upper lightning impulse breakdown junction voltage quantile of the probability density distribution of the lightning impulse discharge voltage; and the acquisition of the upper lightning impulse breakdown junction voltage quantile of the probability density distribution of the lightning impulse discharge voltage is strongly related to the gap distance between the insulator string and the arcing angle, and the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage is strongly related to the maximum operating overvoltage of the system line. Therefore, the reliability evaluation parameters provided by the present invention comprehensively consider the relationship between the insulator string, the arcing angle and the system line; ensure that the arcing angle does not discharge when an operating over-circuit occurs in a normal system line, and the arcing angle discharges before the insulator string when a fault occurs; and can effectively evaluate the reliability of the arcing angle setting scheme.

[0109] The arcing angle reliability assessment method provided by the present invention defines the insulation protection performance of the existing arcing angle by a mathematical analysis method, avoids the selection of a series of experimental methods, is simple to operate and easy to implement, and overcomes the problems of the prior art of determining the reliability of the arcing angle for the insulation coordination of the system line and the insulator string based on experimental research, which is cumbersome to operate and time-consuming and labor-intensive.

[0110] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is 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 method for evaluating arcing angle reliability, characterized in that: The following steps are involved: Calculate the 50% discharge voltage of the arcing angle based on the arcing angle gap distance; Based on the impulse 50% discharge voltage of the arcing angle, combined with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage, the probability density of the operating impulse discharge voltage of the arcing angle and the probability density of the lightning impulse discharge voltage are constructed; Calculate the 50% lightning impulse discharge voltage of the insulator string according to the length of the insulator string, and collect the maximum operating voltage of the system line; The voltage value of the lightning impulse breakdown junction point is calculated by adding the 50% discharge voltage of the arcing angle and the 50% discharge voltage of the lightning impulse of the insulator string and dividing the sum by 2; The probability density distribution of the operating impulse discharge voltage of the arcing angle is normalized so that the 50% impulse discharge voltage of the arcing angle is 0; The upper system line maximum operating voltage quantile of the probability density distribution of the normalized operating impulse discharge voltage of the arcing angle and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage are calculated to obtain reliability evaluation parameters.

2. The arcing angle reliability evaluation method according to claim 1, characterized in that: The impact 50% discharge voltage of the arcing angle is: U z =550 d +80 in, d is the arcing angle gap distance; U z It is the discharge voltage of 50% of the arcing angle.

3. The arcing angle reliability assessment method according to claim 1 or 2, characterized in that: The 50% discharge voltage of the lightning impulse of the insulator string is: U j =553 l +110 in, l is the insulator string length; U j It is the 50% discharge voltage of the lightning impulse of the insulator string.

4. The arcing angle reliability assessment method according to claim 3, characterized in that: The reliability evaluation parameters are: K =（1- A ）· X in, K Parameters for reliability assessment; A is the voltage value quantile of the upper lightning impulse breakdown junction point of the probability density distribution of the lightning impulse discharge voltage; X It is the upper system line maximum operating voltage quantile of the probability density distribution of the operating impulse discharge voltage of the arcing angle.

5. An arcing angle reliability assessment system, characterized in that: include: An arcing angle impulse discharge voltage calculation module is used to calculate the arcing angle impulse 50% discharge voltage based on the arcing angle gap distance; An impulse discharge voltage probability density construction module is used to construct the probability density of the operating impulse discharge voltage of the arcing angle and the probability density of the lightning impulse discharge voltage based on the impulse 50% discharge voltage of the arcing angle, combined with the standard deviation of the probability density of the air gap operating impulse discharge voltage and the standard deviation of the probability density of the air gap lightning impulse discharge voltage; An insulator string lightning impulse discharge voltage calculation module is used to calculate the lightning impulse 50% discharge voltage of the insulator string according to the length of the insulator string; A data acquisition module, used to collect the maximum operating voltage of the system circuit; A lightning impulse breakdown junction voltage calculation module is used to calculate the voltage value of the lightning impulse breakdown junction point by adding the impulse 50% discharge voltage of the arcing angle and the lightning impulse 50% discharge voltage of the insulator string and dividing the sum by 2; A coordinate normalization processing module is used to normalize the probability density distribution of the operation impulse discharge voltage of the arcing angle so that the impulse 50% discharge voltage of the arcing angle is 0; The reliability evaluation parameter calculation module is used to calculate the maximum operating voltage quantile of the upper system line of the probability density distribution of the normalized operating impulse discharge voltage of the arcing angle and the upper lightning impulse breakdown junction voltage value quantile of the probability density distribution of the lightning impulse discharge voltage to obtain reliability evaluation parameters.

6. The arcing angle reliability evaluation system according to claim 5, characterized in that: The impact 50% discharge voltage of the arcing angle is: U z =550 d +80 in, d is the arcing angle gap distance; U z It is the discharge voltage of 50% of the arcing angle.

7. The arcing angle reliability evaluation system according to claim 5 or 6, characterized in that: The 50% discharge voltage of the lightning impulse of the insulator string is: U j =553 l +110 in, l is the insulator string length; U j It is the 50% discharge voltage of the lightning impulse of the insulator string.

8. The arcing angle reliability evaluation system according to claim 7, characterized in that: The reliability evaluation parameters are: K =（1- A ）· X in, K Parameters for reliability assessment; A is the voltage value quantile of the upper lightning impulse breakdown junction point of the probability density distribution of the lightning impulse discharge voltage; X is the maximum operating voltage quantile of the upper system line of the probability density distribution of the operating impulse discharge voltage of the arcing angle.

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