CN114156849A - Pilot protection method for high-voltage transmission line based on current waveform correlation - Google Patents

Pilot protection method for high-voltage transmission line based on current waveform correlation Download PDF

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CN114156849A
CN114156849A CN202111505070.9A CN202111505070A CN114156849A CN 114156849 A CN114156849 A CN 114156849A CN 202111505070 A CN202111505070 A CN 202111505070A CN 114156849 A CN114156849 A CN 114156849A
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phase
current
fault
voltage transmission
transmission line
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宋殷冠
邹宇
池小兵
苏一峰
谢振俊
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Qinzhou Power Supply Bureau of Guangxi Power Grid Co Ltd
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Qinzhou Power Supply Bureau of Guangxi Power Grid Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0092—Details of emergency protective circuit arrangements concerning the data processing means, e.g. expert systems, neural networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
    • H02H7/263—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of measured values

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Artificial Intelligence (AREA)
  • Evolutionary Computation (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a pilot protection method for a high-voltage transmission line based on current waveform correlation, which comprises the following steps: the M, N sides of the high-voltage transmission line are respectively provided with the same relay protection devices, each set of protection devices independently measure the three-phase current of the side, and the three-phase current of the opposite side is obtained through a communication channel; and then recording the acquired current values as two different sets, calculating the correlation degree by a Hausdorff distance principle, judging whether the inside of the high-voltage transmission line has a fault or not by each set of relay protection device according to the calculated magnitude relation between the correlation coefficient of each phase current and the setting value, and starting corresponding protection measures according to the fault category. The invention fully utilizes the characteristic that the short-circuit current waveform of the new energy power supply changes irregularly in the transient process, has high protection reliability and sensitivity and good quick action performance by the constructed new principle, and is suitable for the protection scenes of high-voltage transmission lines in various types.

Description

Pilot protection method for high-voltage transmission line based on current waveform correlation
Technical Field
The invention relates to the field of relay protection of a power system, in particular to a pilot protection method of a high-voltage power transmission line based on current waveform correlation.
Background
For ultrahigh voltage and extra-high voltage alternating current transmission systems, the rapid fault clearing is the most basic and effective measure for improving the transient stability of a power system, and is also the premise that other safety measures can play a role, and in addition, the rapid fault clearing can also reduce the damage of equipment. Therefore, the quick action of the protection algorithm is improved, the fault clearing time is reduced, the safe operation level of the power grid can be effectively improved, and the pilot protection of the line is generally configured for the ultra/extra-high voltage line.
In the aspect of a novel principle of pilot protection, a model identification method, a power calculation method and the like, the action speed is improved, but because double-end voltage quantity data are used, one-end voltage quantity is required to be transmitted to the opposite end, the information transmission quantity is increased, the requirement on a communication channel is high, and the dependence characteristic on a TV is similar to that of the pilot protection. The protection information of the power frequency variation distance protection is obtained from the fault component of the power frequency, has strong quick-action performance, but as the protection based on the single-end quantity, the full-line quick-action of the line cannot be realized. The ultra-high speed protection based on the traveling wave signal realizes the improvement of the speed, however, because the traveling wave signal is very weak when the high resistance is grounded or the voltage zero crossing point is in fault, a certain action dead zone exists. Meanwhile, when the intelligent transformer substation is applied, how to ensure that the traveling wave is reliably measured by using the electronic transformer also has certain difficulty. Therefore, a new principle of a transmission line having more excellent performance needs to be studied.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a pilot protection method of a high-voltage transmission line based on current waveform correlation, which has the advantages of high reliability and sensitivity and good quick action and is suitable for various high-voltage transmission line protection scenes.
The technical scheme of the invention is as follows: a pilot protection method for a high-voltage transmission line based on current waveform correlation comprises the following steps: the M, N sides of the two high-voltage power transmission buses are respectively provided with the same relay protection devices, each set of protection device independently measures the three-phase current of the side, and the three-phase current value of the opposite side at the same moment is obtained through a communication channel; each set of relay protection device carries out correlation coefficient calculation according to the same-name phase current sampling values in the same time window length corresponding to the same time of the side and the opposite side; and each set of relay protection device judges whether the inside of the high-voltage transmission line has a fault according to the calculated magnitude relation between the correlation coefficient of each phase current and the setting value, and then starts corresponding protection measures according to the fault type.
Based on the characteristic that waveforms on two sides of a fault line are not consistent and deform after a fault occurs, a protection principle is constructed by using the fault characteristic of similarity of two current waveforms after the fault occurs, and the similarity of the two waveforms is measured by adopting a correlation coefficient, wherein the calculation principle of the correlation coefficient is as follows:
the current of the phase A measured by the relay protection device on the side M is set to be A, the current value of the phase A measured corresponding to the side N is set to be B, and the expression mode is as follows:
A＝{a1,......,aq} (1)
B＝{b1,.......,bq} (2)
where q denotes the current sampling time point.
Wherein: and (3) performing Euclidean distance calculation and comparison by using a certain point (such as ai) in the set A and all points in the set B, and finding out a point bj nearest to ai to make bj satisfy:
||ai-bj||≤||ai-bk1 is less than or equal to k is less than or equal to q, and k is not equal to j (3)
Wherein | · | | represents the Euclidean distance between two points
Wherein, in the formula (3), floor i ai-bj i is the minimum distance corresponding to the ai point, that is:
Figure BDA0003402939840000031
where the maximum value satisfying equation (4) for all elements in set a is Hausdorff singles from set a to set B, i.e., the maximum value is zero.
Figure BDA0003402939840000032
Wherein, the Hausdorff one-way distance from the set B to the set a is in this analogy:
Figure BDA0003402939840000033
according to kirchhoff's current law, currents on two sides are superposed under the normal condition and the external fault condition of a circuit, theoretically, the value of the formula (5) is 1 compared with the value of the formula (6), the influence of factors such as capacitance current of the circuit, transmission error of a mutual inductor and the like is considered, and the value of the formula (5) is not 1 compared with the value of the formula (6). The following relationship can thus be defined:
Figure BDA0003402939840000034
when the line runs normally, the above relationship is satisfied.
Wherein the setting value is 1.1.
If the correlation coefficient of any phase current in the phase A, the phase B and the phase C is larger than the setting value, the new energy station is protected and judged to send out a single-phase fault in the line, the fault phase is the phase of which the correlation coefficient is larger than the setting value, and the relay protection device sends out an instruction of tripping off the corresponding fault phase circuit breakers.
If the correlation coefficient of any two-phase or three-phase current in the A phase, the B phase and the C phase is larger than the setting value, the new energy station is protected and judged to send out two-phase or three-phase faults in the line, the fault phase is the two-phase or three-phase current with the correlation coefficient larger than the setting value, and the relay protection device sends out an instruction of tripping the three-phase circuit breaker.
If the correlation coefficients of the phase A, the phase B and the phase C are smaller than the setting value, the protection judges that no fault occurs in the transmission line of the new energy station, and the relay protection device does not send a tripping command.
The invention has the following beneficial effects: according to the invention, whether a fault exists in the sending-out line is judged according to the magnitude relation between the correlation coefficient and the setting value by calculating the correlation coefficient of the same-name-phase short-circuit current waveform at the two sides of the sending-out line. The method fully utilizes the characteristic that the short-circuit current waveform of the new energy power supply changes irregularly in the transient process, has high protection reliability and sensitivity and good quick action performance by the constructed new principle, and is suitable for the protection scenes of high-voltage transmission lines in various types.
Drawings
FIG. 1 is a flow chart of a protection method;
FIG. 2 is a diagram of action logic discrimination;
FIG. 3 is a diagram of action logic discrimination;
fig. 4 is a simplified simulation diagram of a high-voltage transmission line with a double-side power supply.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
Fig. 1 is a flowchart of a pilot protection method for a high-voltage power transmission line based on a current waveform correlation degree provided by the invention. As shown in fig. 1, it mainly includes the following steps:
s1 specifically, the same relay protection devices are respectively installed on the high-voltage buses on the two sides of M, N, each set of protection device independently measures the three-phase current of the side, and the three-phase current of the opposite side is obtained through a communication channel
S2 specifically includes: and each set of relay protection device carries out correlation coefficient calculation according to the same-name phase current sampling values in the same time window length corresponding to the same time of the side and the opposite side.
The calculation process of the correlation coefficient is as follows:
(1) and (2) performing set arrangement on the current data obtained by each data window, and acquiring an A-phase current set A (A ═ { a } for the output relay protection device of the M-side high-voltage bus1,......,aqRepresents that the a-phase current collected by the relay protection device at the high-voltage bus outlet on the N side is collected by a set B (B ═ B)1,.......,bq}).
(2) The Euclidean distance calculation is carried out by using a certain point (such as ai) in the set A and all the points in the set B, and the point bj nearest to ai is found, so that bj satisfies
||ai-bj||≤||ai-bk1 is less than or equal to k is less than or equal to q, and k is not equal to j (3)
Where | l | · | |, represents the euclidean distance between two points. Then | | | ai-bj | | | in formula (3) is the minimum distance of the corresponding ai point, i.e.
Figure BDA0003402939840000051
For all elements in set A, the maximum value that satisfies equation (4) is Hausdorff singles from set A to set B, i.e.:
Figure BDA0003402939840000052
and by analogy, the Hausdorff one-way distance from the set B to the set A is as follows:
Figure BDA0003402939840000053
(3) the currents on the two sides are superposed under the normal condition of the line and the condition of an external fault, theoretically, the value of the formula (5) is 1 compared with the value of the formula (6), actually, the influence of factors such as line capacitance current, mutual inductor transmission error and the like is considered, and the value of the formula (5) is not 1 compared with the value of the formula (6).
(4) Setting a discriminant:
Figure BDA0003402939840000054
s3 specifically includes: each set of relay protection device judges whether a fault occurs between the high-voltage buses M, N according to the calculated magnitude relation between the correlation coefficient of each phase current and the setting value, and then starts corresponding protection measures according to the fault type.
The following cases can be mainly classified:
if the correlation coefficients of the phase A, the phase B and the phase C are smaller than the setting value, it is judged that no fault occurs in the transmission line of the new energy station, and the relay protection device does not perform any treatment;
if the correlation coefficient of any phase current in the phase A, the phase B and the phase C is larger than the setting value, the fact that a single-phase fault occurs in the high-voltage transmission bus MN line is judged, the fault phase is the phase of which the correlation coefficient is larger than the setting value, and the relay protection device sends an instruction for tripping the corresponding fault phase circuit breaker;
if the correlation coefficient of any two-phase or three-phase current in the A phase, the B phase and the C phase is larger than the setting value, the two-phase or three-phase fault is judged to occur in the high-voltage transmission bus MN line, the fault phase is the two-phase or three-phase current with the correlation coefficient larger than the setting value, and the relay protection device sends out an instruction of tripping the three-phase circuit breaker.
For better exposition of protection dynamic logic, use HnTo represent
Figure BDA0003402939840000061
Where n represents any of A, B, C three phases. Fig. 2 is a logic diagram of a specific protection operation. Wherein&And represents, ≧ 1 represents a logical OR.
As shown in FIG. 2, when HANot meet the requirements of
Figure BDA0003402939840000062
HBSatisfy the requirement of
Figure BDA0003402939840000063
HCSatisfy the requirement of
Figure BDA0003402939840000064
Tripping the phase A; when H is presentASatisfy the requirement of
Figure BDA0003402939840000065
HBNot meet the requirements of
Figure BDA0003402939840000066
HCSatisfy the requirement of
Figure BDA0003402939840000067
Tripping the phase B; when H is presentASatisfy the requirement of
Figure BDA0003402939840000068
HBSatisfy the requirement of
Figure BDA0003402939840000069
HCNot meet the requirements of
Figure BDA00034029398400000610
Phase B trips.
As shown in FIG. 3, HA、HB、HCAny two phases are not satisfied
Figure BDA00034029398400000611
And then a three-phase tripping instruction is sent.
The closed loop test results of the present invention on a real time simulator (RTDS) of a power system are given below. The schematic diagram of the primary wiring of the simulation system is shown in fig. 4, the voltage level is 100kV, the parameter values of the zero sequence impedance of the positive sequence impedance level and the negative sequence impedance level of the line are shown in table 1, and the setting is performed according to the parameters of table 1.
Table 1: line parameter of extra-high voltage system
Figure BDA00034029398400000612
Figure BDA0003402939840000071
Failure point F1Is set at 200km from the M side, the type of fault is set to be a phase-a ground fault via different excess resistances.
In order to better embody the function of the algorithm, as shown in table 2, Hausdorff distance values of a phase different excess resistance grounding are shown.
Table 2: hausdorff distance value when phase A is grounded through different transition resistors
Figure BDA0003402939840000072
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative rather than restrictive, and it will be apparent to those skilled in the art that many more modifications and variations can be made without departing from the spirit of the invention and the scope of the appended claims.

Claims (4)

1. A pilot protection method for a high-voltage transmission line based on current waveform correlation is characterized by comprising the following steps:
the M, N sides of the two high-voltage power transmission buses are respectively provided with the same relay protection devices, each set of protection device independently measures the three-phase current of the side, and the three-phase current value of the opposite side at the same moment is obtained through a communication channel;
each set of relay protection device carries out correlation coefficient calculation according to the same-name phase current sampling values in the same time window length corresponding to the same time of the side and the opposite side;
each set of relay protection device judges whether a fault occurs in the high-voltage transmission line according to the calculated magnitude relation between the correlation coefficient of each phase current and the setting value, and then starts corresponding protection measures according to the fault type;
if the correlation coefficient of any phase current in the phase A, the phase B and the phase C is greater than the setting value, the new energy station is protected and judged to send out a single-phase fault in the line, the fault phase is the phase with the correlation coefficient greater than the setting value, and the relay protection device sends out an instruction of tripping the corresponding fault phase circuit breaker;
if the correlation coefficient of any two-phase or three-phase current in the A phase, the B phase and the C phase is larger than the setting value, the relay protection device sends an instruction for tripping the three-phase circuit breaker if two-phase or three-phase fault occurs in the high-voltage transmission bus M, N under protection judgment;
if the correlation coefficients of the phase A, the phase B and the phase C are smaller than the setting value, the high-voltage transmission bus M, N is protected and judged to have no fault, and the relay protection device does not send a tripping instruction.
2. The pilot protection method of the high-voltage transmission line based on the current waveform correlation degree according to claim 1, characterized in that based on the characteristic of inconsistent deformation of waveforms on two sides of a fault line after a fault occurs, a protection principle is constructed by using the fault characteristic of the similarity of two current waveforms after the fault occurs, and the similarity of the two waveforms is measured by adopting a correlation coefficient, wherein the calculation principle of the correlation coefficient is as follows:
the current of the phase A measured by the relay protection device on the side M is set to be A, the current value of the phase A measured corresponding to the side N is set to be B, and the expression mode is as follows: where q denotes the current sampling time point.
A＝{a1,......,aq}(1)
B＝{b1,.......,bq}(2)
And (3) performing Euclidean distance calculation and comparison by using a certain point (such as ai) in the set A and all points in the set B, and finding out a point bj nearest to ai to make bj satisfy:
||ai-bj||≤||ai-bk1 is less than or equal to k is less than or equal to q, and k is not equal to j (3)
Wherein, | | | represents the euclidean distance between two points. Then | | | ai-bj | | | in equation (3) is the minimum distance corresponding to the ai point, i.e.:
Figure RE-FDA0003446042590000021
for all elements in set A, the maximum value that satisfies equation (4) is Hausdorff singles from set A to set B, i.e.:
Figure RE-FDA0003446042590000022
and by analogy, the Hausdorff one-way distance from the set B to the set A is as follows:
Figure RE-FDA0003446042590000023
according to kirchhoff's current law, currents on two sides are superposed under the normal condition of a circuit and the condition of an external fault, theoretically, the value of the formula (5) is 1 compared with that of the formula (6), actually, the influence of factors such as capacitance current of the circuit, transmission error of a mutual inductor and the like is considered, and the value of the formula (5) is not 1 compared with that of the formula (6). The following relationship can thus be defined:
Figure RE-FDA0003446042590000024
3. the pilot protection method for the high-voltage transmission line based on the current waveform correlation degree of claim 2, wherein the integral value D issetTaking 1.1, when the formula (7) is not satisfied, the fault is determined.
4. The method for pilot protection of the high-voltage transmission line based on the current waveform correlation degree of claim 2, wherein the adjusting and setting discriminant is applicable to A, B, C three phases.
CN202111505070.9A 2021-12-10 2021-12-10 Pilot protection method for high-voltage transmission line based on current waveform correlation Pending CN114156849A (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106786424A (en) * 2017-01-10 2017-05-31 华北电力大学 Send out method for pilot protection of circuit in new energy station based on current waveform similarity

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106786424A (en) * 2017-01-10 2017-05-31 华北电力大学 Send out method for pilot protection of circuit in new energy station based on current waveform similarity

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
陈乐等: "基于波形相似度比较的线路快速纵联保护研究", 《中国电机工程学报》, vol. 37, no. 17, pages 5018 - 5027 *

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