CN-115133494-B - Zero sequence current compensation coefficient setting method, equipment and medium for cable hybrid line

CN115133494BCN 115133494 BCN115133494 BCN 115133494BCN-115133494-B

Abstract

The application discloses a zero sequence current compensation coefficient setting method, equipment and medium for a cable hybrid line, and belongs to the technical field of hybrid transmission line relay protection. The method comprises the steps of obtaining power frequency impedance and length parameters of an N-section cable mixed circuit, obtaining a comprehensive zero sequence current compensation coefficient K i of each connecting point of the N-section cable mixed circuit, wherein I is greater than or equal to 1 and less than or equal to N and is an integer, obtaining a comprehensive zero sequence compensation coefficient K ' j of a fault point, wherein j is greater than or equal to 1 and less than or equal to N and is an integer, obtaining a comprehensive zero sequence current compensation coefficient K 0 of the tail end of an action range of grounding distance I section protection, judging monotonicity of K ' j , comparing the magnitudes of K 0 and N K i according to the monotonicity, and obtaining a zero sequence current compensation coefficient setting value K, wherein N is greater than or equal to 2 and N is an integer. The application improves the accuracy of zero sequence current compensation coefficient setting, can ensure the reliability of the grounding distance I section protection action and avoid exceeding misoperation when the tail end of the mixed line is in fault.

Inventors

WANG YULONG
HUANG TAO
LU JINFENG
XU XIAOCHUN
ZHAO QINGCHUN
FENG YULEI
DAI GUANGWU
XIE HUA
LI BEN
LIU JINGJING
TAN HAO

Assignees

南京南瑞继保电气有限公司
南京南瑞继保电气有限公司
南京南瑞继保工程技术有限公司
南京南瑞继保工程技术有限公司

Dates

Publication Date: 20260421
Application Date: 20220627
Priority Date: 20220627

Claims (20)

1. The zero sequence current compensation coefficient setting method of the cable hybrid line is characterized by comprising the following steps of: Acquiring power frequency impedance and length parameters of each section of line in the N-section cable mixed line; Acquiring a comprehensive zero sequence current compensation coefficient K i from a first connecting point to i connecting points at the tail end of the N-section cable hybrid line according to the power frequency impedance and the length parameter, wherein i is more than or equal to 1 and less than or equal to N, and i is an integer; Setting a fault point, and acquiring a comprehensive zero sequence compensation coefficient K ' j of the fault point in a j-th section of the cable mixed circuit, wherein j is more than or equal to 1 and less than or equal to N, and j is an integer; according to the K ' j , acquiring a comprehensive zero sequence current compensation coefficient K 0 of the end of the action range of the grounding distance I section protection in the corresponding j-th section of cable mixed line; Judging monotonicity of the comprehensive zero sequence compensation coefficient K ' j according to the power frequency impedance and the length parameter; comparing the magnitudes of the K 0 and the N K i according to the monotonicity to obtain a zero sequence current compensation coefficient setting value K of the tail end of the action range of the grounding distance I section protection; Wherein N is more than or equal to 2 and N is an integer; The monotonicity of the judgment comprehensive zero sequence compensation coefficient K ' j specifically comprises the following steps: When j=1, the comprehensive zero sequence compensation coefficient K ' j of the jth section of line is a constant; when 2≤j≤N and j is an odd number, If it is The comprehensive zero sequence compensation coefficient K ' j of the jth section of line is monotonically decreased; If it is The comprehensive zero sequence compensation coefficient K ' j of the jth section of line is monotonically increased; If it is The comprehensive zero sequence compensation coefficient K ' j of the j-th section line is the same as the comprehensive zero sequence compensation coefficient K ' j-1 of the j-1-th section line; When 2≤j≤N and j is an even number, If it is The comprehensive zero sequence compensation coefficient K ' j of the jth section of line is monotonically increased; If it is The comprehensive zero sequence compensation coefficient K ' j of the jth section of line is monotonically decreased; If it is The comprehensive zero sequence compensation coefficient K ' j of the j-th section line is the same as the comprehensive zero sequence compensation coefficient K ' j-1 of the j-1-th section line; wherein Z j0 is zero sequence impedance of unit length of the jth line, Z j1 is positive sequence impedance of unit length of the jth line, and L j is length of the jth line; When the end of the action range of the grounding distance I section protection is in the j-th section line and j=1, the value of the zero sequence current compensation coefficient setting value K is as follows: ; when the end of the action range of the grounding distance I section protection is in the jth section line and 2 is less than or equal to j < N, If each section in the j-th section to the N-th section meets monotonicity and the section of the wired line is constant, the value of the zero sequence current compensation coefficient setting value K is: ; if the line sections from the j section to the N section do not meet monotonicity, the value of the zero sequence current compensation coefficient setting value K is as follows: ; When the end of the action range of the grounding distance I section protection is at the j-th section line and j=N, If it is The value of the zero sequence current compensation coefficient setting value K is K 0 ; If it is And the value of the zero sequence current compensation coefficient setting value K is K N .
2. The method for setting a zero sequence current compensation coefficient of a cable hybrid according to claim 1, wherein the power frequency impedance and length parameters include positive sequence impedance per unit length of each section of line, zero sequence impedance per unit length of each section of line, and length of each section of line.
3. The method for setting a zero sequence current compensation coefficient of a cable hybrid circuit according to claim 1, wherein the process of obtaining the integrated zero sequence current compensation coefficient K i is: ; where Z i0 is zero sequence impedance of unit length of the i-th line, Z i1 is positive sequence impedance of unit length of the i-th line, and L i is length of the i-th line.
4. The method for setting the zero sequence current compensation coefficient of the cable hybrid circuit according to claim 1, wherein the process of obtaining the integrated zero sequence compensation coefficient K ' j is as follows: ; wherein Z j0 is zero sequence impedance of unit length of the jth line, Z j1 is positive sequence impedance of unit length of the jth line, L j is length of the jth line, and L F is the head end distance between the fault point and the N-section cable hybrid line.
5. The method for adjusting the zero sequence current compensation coefficient of the cable hybrid circuit according to claim 4, wherein the process of obtaining the integrated zero sequence current compensation coefficient K 0 is as follows: And when the tail end of the action range of the grounding distance I section protection is positioned on the jth section line, K 0 =K ' j is formed.
6. A method for setting zero sequence current compensation coefficients of a cable hybrid circuit according to claim 1, wherein, When the comprehensive zero sequence compensation coefficient K ' j of the jth section of line is monotonically increased, the comprehensive zero sequence current compensation coefficient K j of the jth connection point is the maximum value of the comprehensive zero sequence compensation coefficient of the jth section of line; When the comprehensive zero sequence compensation coefficient K ' j of the jth section of line is monotonically decreasing, the comprehensive zero sequence current compensation coefficient K j of the jth connection point is the minimum value of the comprehensive zero sequence compensation coefficient of the jth section of line.
7. A method for zero sequence current compensation coefficient tuning of a cable hybrid according to claim 1 or 2, comprising the steps of, when n=3: Acquiring power frequency impedance and length parameters of a first section of line, a second section of line and a third section of line in the three-section cable mixed line; Acquiring a first connection point comprehensive zero-sequence current compensation coefficient K 1 , a second connection point comprehensive zero-sequence current compensation coefficient K 2 and a line end comprehensive zero-sequence current compensation coefficient K 3 in a three-section cable hybrid line; Setting a fault point, and respectively acquiring a comprehensive zero sequence compensation coefficient K ' 1 of the fault point in a first section of line, a comprehensive zero sequence compensation coefficient K ' 2 of the fault point in a second section of line and a comprehensive zero sequence compensation coefficient K ' 3 of the fault point in a third section of line; According to the K ' 1 、K ' 2 and the K ' 3 , obtaining a comprehensive zero sequence current compensation coefficient K 0 of the end of the action range of the grounding distance I section protection when the end corresponds to the cable mixed line; Judging monotonicity of the comprehensive zero sequence compensation coefficient K ' 2 of the second section line and the comprehensive zero sequence compensation coefficient K ' 3 of the third section line; And according to the monotonicity, comparing the magnitudes of the K 0 、K 1 、K 2 and the K 3 to obtain the zero sequence current compensation coefficient setting value K.
8. The method for setting a zero-sequence current compensation coefficient of a cable hybrid circuit according to claim 7, wherein the process of obtaining the first connection point integrated zero-sequence current compensation coefficient K 1 , the second connection point integrated zero-sequence current compensation coefficient K 2 and the line end integrated zero-sequence current compensation coefficient K 3 is as follows: ; ; ; Wherein Z A0 is zero sequence impedance of the unit length of the first section line, Z A1 is positive sequence impedance of the unit length of the first section line, L A is length of the first section line, Z B0 is zero sequence impedance of the unit length of the second section line, Z B1 is positive sequence impedance of the unit length of the second section line, L B is length of the second section line, Z C0 is zero sequence impedance of the unit length of the third section line, Z C1 is positive sequence impedance of the unit length of the third section line, and L C is length of the third section line.
9. The method for adjusting zero sequence current compensation coefficient of a cable hybrid line according to claim 7, wherein said determining monotonicity of the integrated zero sequence compensation coefficient K ' 2 of the second-stage line further comprises: When (when) When the integrated zero sequence compensation coefficient K ' 2 of the second section line is monotonically increased; When (when) When the integrated zero sequence compensation coefficient K ' 2 of the second section line is monotonically decreasing; When (when) When the integrated zero sequence compensation coefficient K ' 2 of the second section of line is the same as the integrated zero sequence compensation coefficient K ' 1 of the first section of line; Wherein Z A0 is zero sequence impedance of unit length of the first section line, Z A1 is positive sequence impedance of unit length of the first section line, L A is length of the first section line, Z B0 is zero sequence impedance of unit length of the second section line, and Z B1 is positive sequence impedance of unit length of the second section line.
10. A method for setting zero sequence current compensation coefficients of a cable hybrid circuit according to claim 9, wherein, When the comprehensive zero sequence compensation coefficient K ' 2 of the second section line is monotonically increased, the comprehensive zero sequence current compensation coefficient K 2 of the second connection point is the maximum value of the comprehensive zero sequence compensation coefficient of the second section line; When the comprehensive zero sequence compensation coefficient K ' 2 of the second section line is monotonically decreasing, the comprehensive zero sequence current compensation coefficient K 2 of the second connection point is the minimum value of the comprehensive zero sequence compensation coefficient of the second section line.
11. The method for adjusting zero sequence current compensation coefficient of a hybrid cable according to claim 7, wherein determining monotonicity of the integrated zero sequence compensation coefficient K ' 3 of the third-stage cable further comprises: When (when) When the integrated zero sequence compensation coefficient K ' 3 of the third section of line is monotonically decreasing; When (when) When the integrated zero sequence compensation coefficient K ' 3 of the third section of line is monotonically increased; When (when) When the integrated zero sequence compensation coefficient K ' 3 of the third section of line is the same as the integrated zero sequence compensation coefficient K ' 2 of the second section of line; Wherein Z A0 is zero sequence impedance of the first section line, Z A1 is positive sequence impedance of the first section line, L A is length of the first section line, Z B0 is zero sequence impedance of the second section line, Z B1 is positive sequence impedance of the second section line, L B is length of the second section line, Z C0 is zero sequence impedance of the third section line, and Z C1 is positive sequence impedance of the third section line.
12. The method for setting zero sequence current compensation coefficient of a cable hybrid circuit according to claim 11, wherein, When the comprehensive zero sequence compensation coefficient K ' 3 of the third section of line is monotonically increased, the comprehensive zero sequence current compensation coefficient K 3 at the tail end of the line is the maximum value of the comprehensive zero sequence compensation coefficient of the third section of line; When the comprehensive zero sequence compensation coefficient K ' 3 of the third section of line is monotonically decreasing, the comprehensive zero sequence current compensation coefficient K 3 at the tail end of the line is the minimum value of the comprehensive zero sequence compensation coefficient of the third section of line.
13. The method for setting zero sequence current compensation coefficients of a cable hybrid circuit according to claim 7, wherein the obtaining process of the integrated zero sequence compensation coefficient K ' 1 of the fault point in the first section of circuit, the integrated zero sequence compensation coefficient K ' 2 of the fault point in the second section of circuit and the integrated zero sequence compensation coefficient K ' 3 of the fault point in the third section of circuit is as follows: Determining the length L A of the first section of line, the length L B of the second section of line and the total length of the three-section cable hybrid line as L; Determining that the distance between the fault point and the head end of the three-section cable hybrid line is L F ; When (when) When the fault point is located in the first section of line, the calculation process of the comprehensive zero sequence compensation coefficient K ' 1 is as follows: ; When (when) When the fault point is located in the second section of line, the calculation process of the comprehensive zero sequence compensation coefficient K ' 2 is as follows: ; When (when) When the fault point is located in the third section of line, the calculation process of the comprehensive zero sequence compensation coefficient K ' 3 is as follows: ; Wherein Z A0 is zero sequence impedance of unit length of the first section line, Z A1 is positive sequence impedance of unit length of the first section line, Z B0 is zero sequence impedance of unit length of the second section line, Z B1 is positive sequence impedance of unit length of the second section line, Z C0 is zero sequence impedance of unit length of the third section line, and Z C1 is positive sequence impedance of unit length of the third section line.
14. The method for adjusting zero sequence current compensation coefficients of a cable hybrid circuit according to claim 13, wherein the obtaining, according to K ' 1 、K ' 2 and K ' 3 , a comprehensive zero sequence current compensation coefficient K 0 of an end of an action range of the grounding distance I segment protection in a corresponding cable hybrid circuit further includes: K 0 =K ' 1 when the end of the action range of the grounding distance I section protection is positioned on the first section of line; K 0 =K ' 2 when the end of the action range of the grounding distance I section protection is positioned on the second section of line; And when the end of the action range of the grounding distance I section protection is positioned on the third section of line, K 0 =K ' 3 .
15. The method for setting zero-sequence current compensation coefficient of a cable hybrid circuit according to claim 14, wherein when the end of the action range of the grounding distance I section protection is at the first section of circuit, the value of the zero-sequence current compensation coefficient setting value K is: 。
16. The method for setting zero-sequence current compensation coefficient of a cable hybrid circuit according to claim 14, wherein when the end of the action range of the grounding distance I section protection is at the second section of circuit, the value of the zero-sequence current compensation coefficient setting value K is as follows: (a) When (when) In the time-course of which the first and second contact surfaces, ; (B) When (when) In the time-course of which the first and second contact surfaces, ; (C) When (when) In the time-course of which the first and second contact surfaces, ; (D) When (when) 、、、 When the conditions of (a), (b) and (c) are not satisfied, 。
17. The method for setting zero-sequence current compensation coefficient of a cable hybrid circuit according to claim 14, wherein when the end of the action range of the grounding distance I section protection is at the third section of circuit, the value of the zero-sequence current compensation coefficient setting value K is as follows: (a) When (when) In the time-course of which the first and second contact surfaces, ; (B) When (when) In the time-course of which the first and second contact surfaces, 。
18. The method for adjusting the zero sequence current compensation coefficient of the cable hybrid circuit according to claim 1, wherein the action range of the grounding distance section I protection is less than or equal to 80% of the total length of the cable hybrid circuit.
19. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any one of claims 1 to 18 when the computer program is executed.
20. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the method of any one of claims 1 to 18.

Description

Zero sequence current compensation coefficient setting method, equipment and medium for cable hybrid line Technical Field The application belongs to the technical field of mixed power transmission line relay protection, and particularly relates to a zero sequence current compensation coefficient setting method, equipment and medium of a cable mixed line. Background The hybrid transmission line of overhead lines and cables is widely applied in practical engineering, different transmission media can be selected according to the limitation of geographic environments and field requirements, and the transmission capacity and convenience of a power system are greatly improved. The existing line protection device has only a single K value in the zero sequence current compensation coefficient setting, the zero sequence current compensation coefficients of the lines of different sections in the hybrid line are different, the line protection cannot adjust the zero sequence current compensation coefficients in real time according to the actual fault point positions, the zero sequence compensation coefficients only consider the full-length impedance setting zero sequence compensation coefficients of the lines, the actual engineering requirements cannot be met, the grounding distance I section protection of the lines has the risk of exceeding misoperation, and the system safety is threatened. Disclosure of Invention The application aims to provide a zero sequence current compensation coefficient setting method of a cable hybrid circuit, which is used for selecting a proper zero sequence current compensation coefficient according to the monotonicity and the connection value of the comprehensive zero sequence current compensation coefficient of the hybrid circuit in each section of circuit to ensure and improve the reliability of grounding distance protection, and also aims to provide a computer device used for realizing the setting method, and further aims to provide a storage medium used for storing a computer program used for realizing the control method. The application discloses a zero sequence current compensation coefficient setting method of a cable hybrid circuit, which comprises the following steps: Acquiring power frequency impedance and length parameters of each section of line in the N-section cable mixed line; Acquiring a comprehensive zero sequence current compensation coefficient K i from a first connecting point to i connecting points at the tail end of the N-section cable hybrid line according to the power frequency impedance and the length parameter, wherein i is more than or equal to 1 and less than or equal to N, and i is an integer; Setting a fault point, and acquiring a comprehensive zero sequence compensation coefficient K 'j of the fault point in a j-th section of the cable mixed circuit, wherein j is more than or equal to 1 and less than or equal to N, and j is an integer; according to the K 'j, acquiring a comprehensive zero sequence current compensation coefficient K 0 of the end of the action range of the grounding distance I section protection in the corresponding j-th section of cable mixed line; Judging monotonicity of the comprehensive zero sequence compensation coefficient K 'j according to the power frequency impedance and the length parameter; comparing the magnitudes of the K 0 and the N K i according to the monotonicity to obtain a zero sequence current compensation coefficient setting value K of the tail end of the action range of the grounding distance I section protection; Wherein N is more than or equal to 2 and N is an integer. In some embodiments, the comprehensive zero-sequence current compensation coefficient of the first section of the cable hybrid line is a constant function, namely, the comprehensive zero-sequence current compensation coefficient of the first section of the cable hybrid line is always a constant value, and the comprehensive zero-sequence current compensation coefficient of each section of the cable hybrid line starts from the second section of the cable hybrid line, wherein the comprehensive zero-sequence current compensation coefficient of each section of the cable hybrid line shows monotonicity, and the monotonicity can be monotonically increasing or monotonically decreasing. In some embodiments, monotonicity may be used to determine the integrated zero-sequence current compensation coefficient value of the connection point as the maximum value or the minimum value of the zero-sequence current compensation coefficient corresponding to each section of line, where the monotonicity provides a theoretical basis for comparing K 0 with K i, that is, on the premise of determining monotonicity, the comparison between K 0 and K i may be performed, and the setting value of the zero-sequence current compensation coefficient is determined according to the result of the comparison. In some embodiments, the power frequency impedance and length parameters include a posi