CN108627737B - Testing system and testing method for traveling wave ranging locking time - Google Patents
Testing system and testing method for traveling wave ranging locking time Download PDFInfo
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- CN108627737B CN108627737B CN201710153975.1A CN201710153975A CN108627737B CN 108627737 B CN108627737 B CN 108627737B CN 201710153975 A CN201710153975 A CN 201710153975A CN 108627737 B CN108627737 B CN 108627737B
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- G—PHYSICS
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- 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
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- 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
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- G01R31/088—Aspects of digital computing
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Abstract
The invention provides a test system and a test method for traveling wave ranging locking time, which relate to the technical field of relay protection of power systems and can accurately test the traveling wave ranging locking time. The test system for the travelling wave ranging locking time comprises a data memory for storing the length of a line and the propagation speed of travelling waves; a data acquisition unit for acquiring the line wave impedance coefficient; the amplitude calculator is connected with the data acquisition device and is used for obtaining the amplitude of the refraction and reflection wave head of the initial wave head; the amplitude comparator is connected with the amplitude calculator and is used for comparing the amplitude of the catadioptric wave head with a preset threshold value; and the first locking time calculator is connected with the data memory and the amplitude comparator and is used for selecting a catadioptric wave head which reaches the first end of the line to be tested at the latest from the catadioptric wave heads with the amplitude being greater than or equal to the threshold value, and obtaining the first locking time according to the length of the line and the propagation speed of the traveling wave. The testing system is used for testing the traveling wave ranging locking time.
Description
Technical Field
The invention relates to the technical field of power system relay protection, in particular to a testing system and a testing method for traveling wave ranging locking time.
Background
When the traveling wave ranging is carried out, the initial wave head of the traveling wave at the fault point is required to be detected, and then the fault distance from the fault point to the end point of the line to be detected is calculated according to the time when the initial wave head propagates to the end point of the line to be detected. Because the initial wave head can carry out multiple refraction and reflection in the propagation process, a plurality of subsequent refraction and reflection wave heads are generated, and the existence of the subsequent refraction and reflection wave heads can disturb the detection of the initial wave head, so that the detection of the initial wave head is in error. Therefore, in order to ensure accurate detection of the initial wave head, the subsequent catadioptric wave head needs to be avoided, i.e. the device for measuring the distance of the traveling wave should be closed for a period of time and then opened.
However, in the prior art, the blocking time of the traveling wave ranging cannot be accurately calculated. When a line fails, the locking time is usually set by a fitter according to experience, but the locking time set according to experience is not related to the actual line structure and parameters and is often inaccurate. If the set locking time is too short, the subsequent catadioptric wave head is not completely avoided, and the subsequent catadioptric wave head is likely to be identified as an initial wave head to cause the failure of ranging; if the set blocking time is too long, when the faults occur successively, the initial wave head of the fault cannot be identified, so that the fault identification is omitted.
Disclosure of Invention
The invention provides a test system and a test method for the blocking time of travelling wave ranging, which can accurately test the blocking time of the travelling wave ranging.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a first aspect of the present invention provides a system for testing a traveling wave ranging lock-out time, comprising:
the data storage is used for storing the length of a circuit to be tested, the length of a back side circuit of the circuit to be tested, the length of an opposite side circuit of the circuit to be tested and the propagation speed of a traveling wave;
the data acquisition device is used for acquiring the wave impedance coefficient of the line to be detected, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
the amplitude calculator is used for obtaining the amplitude of the catadioptric wave head of the initial wave head according to the wave impedance coefficient of the line to be detected, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
the amplitude comparator is connected with the amplitude calculator and is used for comparing the amplitude of the catadioptric wave head with a preset threshold value;
The first locking time calculator is respectively connected with the data memory and the amplitude comparator and is used for selecting a catadioptric wave head which reaches the first end of the line to be tested at the latest from the catadioptric wave heads with the amplitude being greater than or equal to the threshold value to obtain a first catadioptric wave head; and obtaining the time used by the first refraction-reflection wave head when reaching the first end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is the first locking time.
In the test system for travelling wave ranging locking time provided by the first aspect of the invention, based on the connection relation and the working principle of the data memory, the data collector, the amplitude calculator, the amplitude comparator and the first locking time calculator, the first refraction-reflection wave head which reaches the first end of the line to be tested at the latest can be selected from the subsequent refraction-reflection wave heads with higher amplitude, and then the time used when the first refraction-reflection wave head reaches the first end of the line to be tested is obtained according to the data stored in the data memory, wherein the time is the first locking time. Because the first refraction wave head is the refraction wave head which reaches the first end of the line to be tested at the latest in the refraction wave heads with higher amplitude, namely after the first refraction wave head reaches the first end, no other refraction wave heads are transmitted to the first end. Therefore, the first locking time is set to be the traveling wave ranging locking time, so that after the traveling wave ranging locking time is finished, the refraction and reflection wave heads which are transmitted to the first end can not exist, and the initial wave heads can be accurately detected after the locking time is finished.
The second aspect of the present invention provides a method for testing a traveling wave ranging locking time, comprising:
step S1: storing the length of the line to be measured, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave;
step S2: collecting the wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
step S3: obtaining the amplitude of the refraction-reflection wave head of the initial wave head according to the acquired wave impedance coefficient of the to-be-detected line, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
step S4: comparing the amplitude of the refraction-reflection wave head with a preset threshold value;
step S5: selecting a catadioptric wave head which reaches the first end of the line to be tested at the latest from the catadioptric wave heads with the amplitude value being greater than or equal to the threshold value, and obtaining a first catadioptric wave head; and obtaining the time used by the first refraction-reflection wave head when reaching the first end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is the first locking time.
The beneficial effects of the method for testing the blocking time of the traveling wave ranging provided by the invention are the same as those of the system for testing the blocking time of the traveling wave ranging provided by the first aspect of the invention, and are not repeated here.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a system for testing the blocking time of traveling wave ranging according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a system for testing the blocking time of traveling wave ranging according to a first embodiment of the present invention;
FIG. 3 is a schematic diagram of a system for testing the blocking time of traveling wave ranging according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a system for testing the blocking time of traveling wave ranging according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a system for testing the blocking time of traveling wave ranging according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a circuit structure of an intra-zone fault according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a circuit structure of a forward out-of-zone fault according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a circuit structure of a reverse out-of-zone fault according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of a system for testing the blocking time of traveling wave ranging according to an embodiment of the present invention;
FIG. 10 is a flowchart of a method for testing the blocking time of the traveling wave ranging according to a second embodiment of the present invention;
fig. 11 is a flowchart of a second method for testing the blocking time of the traveling wave ranging according to the second embodiment of the present invention.
Reference numerals illustrate:
1-a data memory; 2-a data collector;
3-an amplitude calculator; a 4-amplitude comparator;
5-a first lock time calculator; 6-a second lock time calculator;
31-a refraction and reflection coefficient calculation module; 32-a wave head amplitude calculation module;
311-a fault point catadioptric coefficient calculating unit;
312-a first-class bus refraction and reflection coefficient calculation unit;
313-a second type bus refraction and reflection coefficient calculation unit;
314-a third class bus refraction and reflection coefficient calculation unit;
321-an intra-zone fault magnitude calculation unit; 322-a forward out-of-zone fault magnitude calculation unit;
323-a reverse out-of-zone fault magnitude calculation unit; 51-an addition operation module;
52-division operation module.
Detailed Description
In order to make the above objects, features and advantages of the present invention more comprehensible, the following description of the embodiments accompanied with the accompanying drawings will be given in detail. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The embodiment provides a traveling wave ranging locking time testing system, as shown in fig. 1, which specifically includes a data memory 1, a data collector 2, an amplitude calculator 3, an amplitude comparator 4 and a first locking time calculator 5.
The data storage 1 is used for storing the length of a line to be tested, the length of a back side line of the line to be tested, the length of an opposite side line of the line to be tested and the propagation speed of a traveling wave.
The data collector 2 is used for collecting the wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line.
The amplitude calculator 3 is connected with the data collector 2, and the amplitude calculator 3 is used for obtaining the amplitude of the catadioptric wave head of the initial wave head according to the wave impedance coefficient of the line to be detected, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line.
The amplitude comparator 4 is connected with the amplitude calculator 3, and the amplitude comparator 4 is used for comparing the amplitude of the catadioptric wave head with a preset threshold value.
The first locking time calculator 5 is respectively connected with the data memory 1 and the amplitude comparator 4, and the first locking time calculator 5 is used for selecting a catadioptric wave head which reaches the first end of the line to be tested at the latest in the catadioptric wave heads with the amplitude being greater than or equal to a threshold value to obtain a first catadioptric wave head; according to the length of the line to be measured, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, the time for the first refraction-reflection wave head to reach the first end of the line to be measured is obtained, and the time is the first locking time; the traveling wave ranging locking time is a first locking time.
In the test system for travelling wave ranging locking time provided in this embodiment, based on the connection relationship and the working principle of the data memory 1, the data collector 2, the amplitude calculator 3, the amplitude comparator 4 and the first locking time calculator 5, the first refraction-reflection wave head reaching the first end of the line to be tested at the latest can be selected from the subsequent refraction-reflection wave heads with higher amplitude, and then the time used when the first refraction-reflection wave head reaches the first end of the line to be tested is obtained according to the data stored in the data memory 1, wherein the time is the first locking time. Because the first refraction wave head is the refraction wave head which reaches the first end of the line to be tested at the latest in the refraction wave heads with higher amplitude, namely after the first refraction wave head reaches the first end, no other refraction wave heads are transmitted to the first end. Therefore, the first locking time is set to be the traveling wave ranging locking time, so that after the traveling wave ranging locking time is finished, the refraction and reflection wave heads which are transmitted to the first end can not exist, and the initial wave heads can be accurately detected after the locking time is finished.
Therefore, by adopting the test system for the traveling wave ranging locking time provided by the embodiment, the traveling wave ranging locking time can be accurately tested, so that the problems of ranging failure or missing fault identification caused by unscientific setting of the locking time in the prior art are avoided.
In practical application, the initial wave head is infinitely folded and reflected, but the detection device cannot be always in a locking state, so that the locking time only needs to avoid the folded and reflected wave head with larger intensity, namely, the folded and reflected wave head with the amplitude larger than or equal to the threshold value.
Furthermore, as shown in fig. 2, the test system for traveling wave ranging lock-out time may further include a second lock-out time calculator 6. The second locking time calculator 6 is respectively connected with the data memory 1 and the amplitude comparator 4, and the second locking time calculator 6 is used for selecting a catadioptric wave head which reaches the second end of the line to be tested at the latest from the catadioptric wave heads with the amplitude being greater than or equal to a threshold value to obtain a second catadioptric wave head; obtaining the time used by the second refraction and reflection wave head when reaching the second end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is the second locking time; the traveling wave ranging locking time is the maximum value of the first locking time and the second locking time.
When the test system of the traveling wave ranging locking time comprises the second locking time calculator 6, the time used by the refraction-reflection wave heads reaching the two end points of the line to be tested at the latest can be measured simultaneously, and the traveling wave ranging locking time can be further ensured to avoid all the refraction-reflection wave heads with higher amplitude by setting the maximum value of the first locking time and the second locking time as the traveling wave ranging locking time, so that the accurate detection of the initial wave head is ensured.
As shown in fig. 3, in the test system for traveling wave ranging lock-in time provided in the present embodiment, the amplitude calculator 3 may specifically include a refraction-reflection coefficient calculation module 31 and a wave head amplitude calculation module 32.
The refraction and reflection coefficient calculating module 31 is connected to the data collector 2, and the refraction and reflection coefficient calculating module 31 is configured to obtain a current refraction and reflection coefficient of a fault point, a current refraction and reflection coefficient of a bus at two ends of the line to be tested, a current refraction and reflection coefficient of a back bus, and a current refraction and reflection coefficient of a opposite bus according to the wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back line, and the wave impedance coefficient of the opposite line, respectively.
The buses at two ends of the to-be-tested line are corresponding buses at two end points of the to-be-tested line.
The wave head amplitude calculating module 32 is respectively connected with the refraction and reflection coefficient calculating module 31 and the amplitude comparator 4, and the wave head amplitude calculating module 32 is used for obtaining the amplitude of the refraction and reflection wave head of the initial wave head according to the current refraction and reflection coefficient of the fault point, the current refraction and reflection coefficient of the bus at the two ends of the line to be tested, the current refraction and reflection coefficient of the bus at the back side and the current refraction and reflection coefficient of the bus at the opposite side.
In practical application, the buses at two ends, the back side and the opposite side of the line to be tested are respectively of three types: a first type of bus with one-circuit outlet, a second type of bus with two-circuit outlet and a third type of bus with three-circuit outlet and more than three-circuit outlet. Therefore, in order to obtain the current refraction and reflection coefficients of the buses at the two ends of the line to be tested, the current refraction and reflection coefficients of the buses at the back side and the current refraction and reflection coefficients of the buses at the opposite side, the current refraction and reflection coefficients of the three buses need to be calculated respectively. After the refraction and reflection coefficients of the first type bus, the second type bus and the third type bus are determined, the current refraction and reflection coefficients of the buses at the two ends of the line to be tested correspond to the current refraction and reflection coefficients of the buses with the same type; the current refraction and reflection coefficient of the bus on the back side corresponds to the current refraction and reflection coefficient of the bus with the same type; the current refraction coefficient of the opposite bus corresponds to the current refraction coefficient of the bus with the same type.
As shown in fig. 4, the refraction-reflection coefficient calculating module 31 may specifically include a fault point refraction-reflection coefficient calculating unit 311, a first type bus bar refraction-reflection coefficient calculating unit 312, a second type bus bar refraction-reflection coefficient calculating unit 313, and a third type bus bar refraction-reflection coefficient calculating unit 314, which are respectively connected to the data collector 2.
Specifically, the fault point catadioptric coefficient calculating unit 311 is configured to calculate, according to the wave impedance coefficient of the line to be tested, the current catadioptric coefficient of the fault point according to formula (1), where the current catadioptric coefficient of the fault point includes the current refractive coefficient α of the fault point F And the current reflection coefficient beta of the fault point F 。
Wherein Z is 1 And Z 0 Line mode impedance and zero mode impedance of unit length of line respectively, R f Is a fault transition resistance.
The fault transition resistor R f The value of (2) can be obtained through prediction, and the maximum transition resistance value of the refraction and reflection wave head can also be obtained.
The first bus bar catadioptric coefficient calculating unit 312 is configured to calculate the current catadioptric coefficient of the first bus bar according to the wave impedance coefficient of the line to be measured, the wave impedance coefficient of the back side line, and the wave impedance coefficient of the opposite side line according to formula (2), where the current catadioptric coefficient of the first bus bar includes the current refractive coefficient α of the first bus bar ZC And the current reflection coefficient beta of the first bus ZC 。
Wherein C is the stray capacitance of the bus, Z is the wave impedance of the unit length of the line, and omega is the angular frequency.
The second type bus refraction-reflection coefficient calculation unit 313 is configured to obtain the traveling wave from the wave impedance to Z according to the wave impedance coefficient of the line to be measured, the wave impedance coefficient of the back side line, and the wave impedance coefficient of the opposite side line by equation (3) i Is transmitted to the wave impedance Z j The current refraction coefficient of the second type bus comprises the current refraction coefficient alpha of the second type bus ij And the current reflection coefficient beta of the second type bus ij 。
The third bus refraction-reflection coefficient calculating unit 314 is configured to obtain the traveling wave from the wave impedance to Z according to the wave impedance coefficient of the line to be measured, the wave impedance coefficient of the back-side line, and the wave impedance coefficient of the opposite-side line by equation (4) m Is transmitted to the wave impedance Z n The current refraction coefficient of the third bus bar, wherein the current refraction coefficient of the third bus bar comprises the current refraction coefficient alpha of the third bus bar mn And the current refraction and reflection coefficient beta of the third bus mn 。
Wherein Z is Σ Is the equivalent impedance of the line connected with the third bus.
Based on the above calculation, for example, when the type of the backside bus bar is the second type bus bar, the refraction and reflection coefficient of the backside bus bar is obtained by the refraction and reflection coefficient calculation formula (3) of the second type bus bar; when the type of the opposite side bus is the third bus, the refraction and reflection coefficient of the opposite side bus is obtained through a calculation formula (4) of the refraction and reflection coefficient of the third bus.
It will be appreciated that it is not known whether the fault belongs to an intra-zone fault, a forward out-of-zone fault, or a reverse out-of-zone fault, prior to a specific detection of the fault distance. In order to ensure that all the reflectances with magnitudes greater than or equal to the threshold can be screened out, all the magnitudes of the reflectances under the three fault conditions need to be calculated.
Specifically, as shown in fig. 5, the wave head amplitude calculation module 32 may specifically include an intra-zone fault amplitude calculation unit 321, a forward-direction out-of-zone fault amplitude calculation unit 322, and a reverse-direction out-of-zone fault amplitude calculation unit 323, which are respectively connected to the refraction-reflection coefficient calculation module 31.
The in-zone fault amplitude calculating unit 321 is configured to obtain an amplitude of the reflection wave head during in-zone fault according to the current reflection coefficient of the fault point, the current reflection coefficient of the bus at the two ends of the line to be tested, the current reflection coefficient of the back bus, and the current reflection coefficient of the opposite bus.
The following specifically describes the calculation of the amplitude of the catadioptric wave head at the time of the intra-zone fault, taking the schematic circuit diagram of the intra-zone fault shown in fig. 6 as an example. Wherein Z is 1 The line is the line to be measured (shown as MN in the figure), Z 2 The line is the first backside Line (LM) adjacent to the line to be tested in the backside lines, Z 3 The line is a second back side line adjacent to the first back side line, Z 4 The line is the opposite line. Assuming that the M point is the first end of the line to be tested, the N point is the second end of the line to be tested, the bus perpendicular to the line to be tested in the line where the M point is located is the first end bus of the line to be tested, the bus perpendicular to the line to be tested in the line where the N point is located is the second end bus of the line to be tested, the bus perpendicular to the first back side line in the line where the L point is located is the back side bus, the types of the first end bus of the line to be tested, the second end bus of the line to be tested and the back side bus are the second type bus or the third type bus, and R f The fault transition resistance is represented by R, F, i 0 For the fault initial wave head, i 1 ～i 3 Is the subsequent catadioptric wave head. And when the fault exists in the area, the fault point is positioned in the line to be tested.
Subsequent catadioptric wave head i 1 Is of the amplitude of (a) k 1 ，k 1 ＝β 12 β 1F Subsequent catadioptric wave head i 2 Is k in amplitude 2 ，k 1 ＝β 14 α 1F Subsequent catadioptric wave head i 3 Is k in amplitude 3 ，k 3 ＝β 23 α 21 。
Wherein beta is 12 To be Z from the wave impedance 1 Line-to-wave impedance of Z 2 The current reflection coefficient of the line to be measured, namely the current reflection coefficient of the bus at the first end of the line to be measured; beta 1F Current reflection coefficient for fault point; beta 14 To be Z from the wave impedance 1 Is transmitted to the wave impedance Z 4 The current reflection coefficient of the circuit, namely the current reflection coefficient of the bus at the second end of the circuit to be tested; alpha 1F Current refractive index for the fault point; beta 23 To be Z from the wave impedance 2 Is transmitted to the wave impedance Z 3 The current reflection coefficient of the line of (a), namely the current refraction coefficient of the back side bus; alpha 21 To be Z from the wave impedance 2 Line-to-wave impedance of Z 1 The current refractive index of the line, i.e. the refractive index of the busbar at the first end of the line to be measured.
It should be noted that, corresponding beta at the time of failure in the region 1F I.e. the current reflection coefficient beta of the fault point shown in formula (1) F 。
The positive out-of-zone fault amplitude calculating unit 322 is configured to obtain an amplitude of the reflection wave head during the positive out-of-zone fault according to the current reflection coefficient of the fault point, the current reflection coefficient of the bus at the two ends of the line to be tested, the current reflection coefficient of the back bus, and the current reflection coefficient of the opposite bus.
The following specifically describes the calculation of the amplitude of the catadioptric wave head at the time of the forward out-of-zone fault, taking the schematic circuit diagram of the forward out-of-zone fault shown in fig. 7 as an example. Wherein Z is 1 The line is the line to be measured (shown as MN in the figure), Z 2 The line is the first backside Line (LM) adjacent to the line to be tested in the backside lines, Z 3 The line is a second back side line adjacent to the first back side line, Z 4 Line of siteFor the first opposite side line adjacent to the line to be tested, Z 5 The line is a second pair of side lines adjacent to the first pair of side lines. Assuming that the M point is the first end of the line to be tested, the N point is the second end of the line to be tested, the bus perpendicular to the line to be tested in the line where the M point is located is the first end bus of the line to be tested, the bus perpendicular to the line to be tested in the line where the N point is located is the second end bus of the line to be tested, the bus perpendicular to the first back side line in the line where the L point is located is the back side bus, the bus perpendicular to the first opposite side line in the line where the P point is located is the opposite side bus, the types of the first end bus of the line to be tested, the second end bus of the line to be tested, the back side bus and the opposite side bus are the second type bus or the third type bus, R f The fault transition resistance is represented by R, F, i 0 For the fault initial wave head, i 1 ～i 4 Is the subsequent catadioptric wave head. It can be seen that in the case of a forward out-of-zone fault, the fault point is located in the opposite line.
Subsequent catadioptric wave head i 1 Is k in amplitude 1 '，k 1 '＝β 12 'β 14 ' subsequent catadioptric wave head i 2 Is k in amplitude 2 '，k 2 '＝β 41 'β 4F ' subsequent catadioptric wave head i 3 Is k in amplitude 3 '，k 3 '＝β 45 'β 4F ' subsequent catadioptric wave head i 4 Is k in amplitude 4 '，k 4 '＝β 23 'α 21 '。
Wherein beta is 12 ' from wave impedance Z 1 Line-to-wave impedance of Z 2 The current reflection coefficient of the line to be measured, namely the current reflection coefficient of the bus at the first end of the line to be measured; beta 14 ' from wave impedance Z 1 Line-to-wave impedance of Z 4 The current reflection coefficient of the circuit, namely the current reflection coefficient of the bus at the second end of the circuit to be tested; beta 41 ' from wave impedance Z 4 Line-to-wave impedance of Z 1 The current reflection coefficient of the circuit, namely the current reflection coefficient of the bus at the second end of the circuit to be tested; beta 4F ' is the current reflection coefficient of the fault point; beta 45 ' from wave impedance Z 4 Line-to-wave impedance of (c)Is Z 5 The current reflection coefficient of the line of (a) is the current reflection coefficient of the opposite bus; beta 23 ' from wave impedance Z 2 Line-to-wave impedance of Z 3 The current reflection coefficient of the line of (a) is that of the back side bus; alpha 21 ' from wave impedance Z 2 Line-to-wave impedance of Z 1 The current refractive index of the line of the first end bus of the line to be measured.
It should be noted that, corresponding beta in the case of a positive out-of-zone fault 4F ' is the current reflection coefficient beta of the fault point shown in formula (1) F 。
The reverse region external fault amplitude calculating unit 323 is configured to obtain an amplitude of the reflection wave head during the reverse region external fault according to the current reflection coefficient of the fault point, the current reflection coefficient of the bus at the two ends of the line to be tested, the current reflection coefficient of the back bus, and the current reflection coefficient of the opposite bus.
The following specifically describes the calculation of the amplitude of the catadioptric wave head at the time of the reverse-out-of-zone fault, taking the schematic circuit diagram of the reverse-out-of-zone fault shown in fig. 8 as an example. The meaning of the letters in fig. 8 is the same as that of the corresponding letters in fig. 6, and will not be described again here. As can be seen from fig. 8, in the event of a reverse out-of-zone fault, the fault point is located in the backside line.
Subsequent catadioptric wave head i 1 Is k in amplitude 1 ″，k 1 ″＝β 21 ″β 2F Subsequent catadioptric wave head i 2 Is k in amplitude 2 ″，k 2 ″＝β 14 ″α 12 Subsequent catadioptric wave head i 3 Is k in amplitude 3 ″，k 3 ″＝β 23 ″α 2F ″。
Wherein beta is 21 "from wave impedance to Z 2 Line-to-wave impedance of Z 1 The current reflection coefficient of the line to be measured, namely the current reflection coefficient of the bus at the first end of the line to be measured; beta 2F "is the current reflection coefficient of the fault point; beta 14 "from wave impedance to Z 1 Line-to-wave impedance of Z 4 The current reflection coefficient of the circuit, namely the current reflection coefficient of the bus at the second end of the circuit to be tested; alpha 12 "from wave impedance to Z 1 Line-to-wave impedance of Z 2 The current refractive index of the line to be measured, namely the current refractive index of the bus at the first end of the line to be measured; beta 23 "from wave impedance to Z 2 Line-to-wave impedance of Z 3 The current reflection coefficient of the line of (a) is that of the back side bus; alpha 2F "is the current refractive index of the fault point.
It should be noted that, corresponding beta in case of reverse out-of-zone failure 2F "is the current reflection coefficient beta of the fault point shown in formula (1) F ，α 2F "that is, the current refractive index α of the fault point shown in formula (1) F 。
After the amplitudes of all the catadioptric wave heads under the conditions of the internal faults, the external faults and the external faults of the forward region are obtained, the amplitude comparator 4 can compare the amplitudes of all the catadioptric wave heads under the three conditions with a preset threshold value.
As shown in fig. 9, in the test system for traveling wave ranging lock-out time provided in the present embodiment, the first lock-out time calculator 5 includes an addition module 51 and a division module 52. Specifically, the adding module 51 may be an adding circuit, and the dividing module 52 may be a dividing circuit.
The adding module 51 is connected to the data memory 1 and the amplitude comparator 4, and the adding module 51 is configured to obtain a total length of a line propagated when the first refractive wave head reaches the first end of the line to be measured according to a length of the line to be measured, a length of the back side line, and a length of the opposite side line.
Taking the schematic diagram of the line structure of the fault in the area shown in fig. 6 as an example again, the first end of the line to be tested is the point M, and the wave head i is refracted and reflected 1 Total length of line propagating to point M 1 For the length of two lines to be tested, i.e. l 1 =2mn; reflection wave head i 2 Total length of line propagating to point M 2 For the length of the line from the two points F to N and the length of one line to be tested, i.e.) 2 =2nf+mn; reflection wave head i 3 Total length of line propagating to point M 3 For the length of a line from point F to point P, for the length of a line from point N to point P, and for the length of a line to be tested, i.e.) 3 ＝FP+NP+MN。
The first refraction wave head is a refraction wave head i 1 ～i 3 In any one of the above cases, the total length l of the line propagating through the first catadioptric wave head is the total length of the line propagating through the corresponding catadioptric wave head.
The division operation module 52 is respectively connected with the data memory 1 and the addition operation module 51, and the division operation module 52 is configured to calculate the total length l of the line propagating from the propagation velocity V of the traveling wave and the first refraction-reflection wave head reaching the first end of the line to be measured according to t 1 The time taken for the first refracted wave head to reach the first end of the line under test is calculated as l/V, which is the first lock-out time.
It is understood that, when the testing system for traveling wave ranging locking time includes the second locking time calculator 6, the second locking time calculator 6 may also include an addition operation module and a division operation module, and the connection manner of the addition operation module and the division operation module included in the second locking time calculator 6 and the connection manner of the addition operation module 51 and the division operation module 52 included in the first locking time calculator 5 are the same as the working principle, which is not repeated herein.
Example two
The embodiment provides a method for testing the blocking time of travelling wave ranging, which is applied to the system for testing the blocking time of travelling wave ranging provided in the embodiment.
As shown in fig. 10, the method for testing the traveling wave ranging locking time specifically includes:
step S1: the length of the line to be measured, the length of the back side line, the length of the opposite side line, and the propagation speed of the traveling wave are stored.
Step S2: the wave impedance coefficient of the line to be measured, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line are collected.
Step S3: and obtaining the amplitude of the refraction and reflection wave head of the initial wave head according to the acquired wave impedance coefficient of the to-be-detected line, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line.
Step S4: and comparing the amplitude of the catadioptric wave head with a preset threshold value.
Step S5: selecting a refraction-reflection wave head which reaches the first end of the line to be tested at the latest from refraction-reflection wave heads with the amplitude value being greater than or equal to a threshold value, and obtaining a first refraction-reflection wave head; and obtaining the time for the first refraction-reflection wave head to reach the first end of the line to be measured according to the length of the line to be measured, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is first locking time, and the first locking time is traveling wave ranging locking time.
The threshold value of the amplitude of the catadioptric wave head can be specifically defined according to specific situations, and optionally, the threshold value can be set to be 0.3.
Because the testing method of the traveling wave ranging locking time provided by the embodiment is applied to the testing system of the traveling wave ranging locking time provided by the first embodiment, the testing method of the traveling wave ranging locking time provided by the embodiment can be used for accurately testing the traveling wave ranging locking time, so that the problem that the ranging failure or fault identification is omitted due to unscientific setting of the locking time in the prior art is avoided.
For example, in the prior art, the deployment personnel usually set the minimum traveling wave ranging locking time to 20ms according to experience, and the locking time calculated by the testing method of the traveling wave ranging locking time provided by the embodiment can be precisely about 5ms, so that the locking time is greatly shortened, and further, the problem of missing fault identification caused by overlong locking time setting can be avoided.
In addition, as shown in fig. 10, step S5 may further include:
step S5': selecting a catadioptric wave head which reaches the second end of the line to be tested at the latest from the catadioptric wave heads with the amplitude value being greater than or equal to the threshold value, and obtaining a second catadioptric wave head; and obtaining the time used by the second refraction and reflection wave head to reach the second end of the circuit to be tested according to the length of the circuit to be tested, the length of the back side circuit, the length of the opposite side circuit and the propagation speed of the traveling wave, wherein the time is the second locking time.
After the step S5 and the step S5' are executed, the testing method of the traveling wave ranging locking time further comprises the following steps:
step S6: judging whether the first locking time is greater than or equal to the second locking time, if so, the travelling wave ranging locking time is the first locking time; if not, the traveling wave ranging locking time is the second locking time.
The time used by the refraction-reflection wave heads reaching the two end points of the line to be detected at the latest is measured, and the maximum value in the first locking time and the second locking time is set to be the traveling wave ranging locking time, so that the traveling wave ranging locking time can be further ensured to avoid all refraction-reflection wave heads with higher amplitude values, and the initial wave head is ensured to be accurately detected.
The step S3 in the method for testing the traveling wave ranging locking time provided in this embodiment may specifically include:
step S31: and respectively obtaining the current refraction and reflection coefficients of the fault point, the bus bars at the two ends of the line to be tested, the back bus bar and the opposite bus bar according to the acquired wave impedance coefficient of the line to be tested, the back line and the opposite bus bar.
The buses at two ends of the to-be-tested line are buses corresponding to two end points of the to-be-tested line.
Step S32: and obtaining the amplitude of the catadioptric wave head of the initial wave head according to the obtained current catadioptric coefficient of the fault point, the current catadioptric coefficients of the buses at the two ends of the line to be tested, the current catadioptric coefficient of the bus at the back side and the current catadioptric coefficient of the bus at the opposite side.
In practical application, the buses at two ends, the back side and the opposite side of the line to be tested are respectively of three types: a first type of bus with one-circuit outlet, a second type of bus with two-circuit outlet and a third type of bus with three-circuit outlet and more than three-circuit outlet. Therefore, in order to obtain the current refraction and reflection coefficients of the buses at the two ends of the line to be tested, the current refraction and reflection coefficients of the buses at the back side and the current refraction and reflection coefficients of the buses at the opposite side, the current refraction and reflection coefficients of the three buses need to be calculated respectively.
Specifically, step S31 specifically includes:
obtaining a current refraction and reflection coefficient of a fault point according to the acquired wave impedance coefficient of the line to be tested through a formula (1), wherein the current refraction and reflection coefficient of the fault point comprises a current refraction coefficient alpha of the fault point F And the current reflection coefficient beta of the fault point F 。
Wherein Z is 1 And Z 0 Line mode impedance and zero mode impedance of unit length of line respectively, R f Is a fault transition resistance.
The fault transition resistor R f The value of (2) can be obtained through prediction, and the maximum transition resistance value of the refraction and reflection wave head can also be obtained.
Obtaining a current refraction and reflection coefficient of a first type bus according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line through a formula (2), wherein the current refraction and reflection coefficient of the first type bus comprises a current refraction and reflection coefficient alpha of the first type bus ZC And the current reflection coefficient beta of the first bus ZC 。
Wherein C is the stray capacitance of the bus, Z is the wave impedance of the unit length of the line, and omega is the angular frequency.
Obtaining the traveling wave from the wave impedance Z according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line by the formula (3) i Is transmitted to the wave impedance asZ j The current refraction coefficient of the second type bus comprises the current refraction coefficient alpha of the second type bus ij And the current reflection coefficient beta of the second type bus ij 。
Obtaining the traveling wave from the wave impedance Z according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line by the formula (4) m Is transmitted to the wave impedance Z n The current refraction coefficient of the third class bus bar, wherein the current refraction coefficient of the third class bus bar comprises the current refraction coefficient alpha of the third class bus bar mn And the current refraction and reflection coefficient beta of the third bus mn 。
Wherein Z is Σ Is the equivalent impedance of the line connected to the third type of bus.
The current refraction and reflection coefficients of the buses at the two ends of the line to be tested respectively correspond to the current refraction and reflection coefficients of the first type buses, the current refraction and reflection coefficients of the second type buses or the current refraction and reflection coefficients of the third type buses which are the same as the current refraction and reflection coefficients of the first type buses; the current refraction and reflection coefficient of the back side bus corresponds to the current refraction and reflection coefficient of the first bus, the current refraction and reflection coefficient of the second bus or the current refraction and reflection coefficient of the third bus which are the same with the back side bus; the current refraction and reflection coefficients of the opposite side bus bar correspond to the current refraction and reflection coefficients of the first bus bar, the second bus bar or the third bus bar which are the same as the opposite side bus bar.
For example, when the type of the backside bus bar is the second type bus bar, the refraction and reflection coefficient of the backside bus bar is obtained by the refraction and reflection coefficient calculation formula (3) of the second type bus bar; when the type of the opposite side bus is the third bus, the refraction and reflection coefficient of the opposite side bus is obtained through a calculation formula (4) of the refraction and reflection coefficient of the third bus.
Since it is not known whether the fault belongs to an intra-zone fault, a forward out-of-zone fault, or a reverse out-of-zone fault, before the fault distance is specifically detected. In order to ensure that all the reflectances with magnitudes greater than or equal to the threshold can be screened out, all the magnitudes of the reflectances under the three fault conditions need to be calculated.
Correspondingly, the step S32 specifically includes:
and obtaining the amplitude of the catadioptric wave head during the fault in the area according to the obtained current catadioptric coefficient of the fault point, the current catadioptric coefficients of the buses at the two ends of the line to be tested, the current catadioptric coefficient of the bus at the back side and the current catadioptric coefficient of the bus at the opposite side.
And obtaining the amplitude of the catadioptric wave head in the case of the fault outside the forward region according to the obtained current catadioptric coefficient of the fault point, the current catadioptric coefficients of the buses at the two ends of the line to be tested, the current catadioptric coefficient of the bus at the back side and the current catadioptric coefficient of the bus at the opposite side.
And obtaining the amplitude of the catadioptric wave head in the case of the fault outside the reverse region according to the obtained current catadioptric coefficient of the fault point, the current catadioptric coefficients of the buses at the two ends of the line to be tested, the current catadioptric coefficient of the bus at the back side and the current catadioptric coefficient of the bus at the opposite side.
In addition, in the method for testing the traveling wave ranging locking time provided in the present embodiment, step S5 may specifically include:
step S51: and obtaining the total length of the line propagated when the first refraction-reflection wave head reaches the first end of the line to be measured according to the stored length of the line to be measured, the length of the back side line and the length of the opposite side line.
Step S52: and obtaining the time used by the first refraction-reflection wave head when reaching the first end of the line to be tested according to the stored propagation speed of the traveling wave and the total length of the line propagated by the first refraction-reflection wave head when reaching the first end of the line to be tested, wherein the time is the first locking time.
It can be appreciated that, when the testing method of the traveling wave ranging locking time includes the step S5', the step S5' may specifically include:
step S51': and obtaining the total length of the line propagated when the second refraction-reflection wave head reaches the second end of the line to be measured according to the stored length of the line to be measured, the length of the back side line and the length of the opposite side line.
Step S52': and obtaining the time used by the first refraction-reflection wave head when reaching the second end of the line to be tested according to the stored propagation speed of the traveling wave and the total length of the line propagated by the second refraction-reflection wave head when reaching the second end of the line to be tested, wherein the time is the second locking time.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A test system for traveling wave ranging lock-out time, comprising:
the data storage is used for storing the length of a circuit to be tested, the length of a back side circuit of the circuit to be tested, the length of an opposite side circuit of the circuit to be tested and the propagation speed of a traveling wave;
the data acquisition device is used for acquiring the wave impedance coefficient of the line to be detected, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
The amplitude calculator is used for obtaining the amplitude of the catadioptric wave head of the initial wave head according to the wave impedance coefficient of the line to be detected, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
the amplitude comparator is connected with the amplitude calculator and is used for comparing the amplitude of the catadioptric wave head with a preset threshold value;
the first locking time calculator is respectively connected with the data memory and the amplitude comparator and is used for selecting a catadioptric wave head which reaches the first end of the line to be tested at the latest from the catadioptric wave heads with the amplitude being greater than or equal to the threshold value to obtain a first catadioptric wave head; obtaining the time used by the first refraction-reflection wave head when reaching the first end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is a first locking time;
the test system of the traveling wave ranging locking time further comprises:
the second locking time calculator is respectively connected with the data memory and the amplitude comparator and is used for selecting a catadioptric wave head which reaches the second end of the line to be tested at the latest from the catadioptric wave heads with the amplitude larger than or equal to the threshold value to obtain a second catadioptric wave head; and obtaining the time used by the second refraction-reflection wave head when reaching the second end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is second locking time, and the traveling wave ranging locking time is the maximum value of the first locking time and the second locking time.
2. The traveling wave ranging lock-out time test system according to claim 1, wherein the amplitude calculator comprises a refraction-reflection coefficient calculation module and a wave head amplitude calculation module;
the refraction and reflection coefficient calculation module is connected with the data acquisition device and is used for respectively obtaining the current refraction and reflection coefficient of a fault point, the current refraction and reflection coefficient of buses at two ends of the circuit to be detected, the current refraction and reflection coefficient of a back side bus and the current refraction and reflection coefficient of a contralateral bus according to the wave impedance coefficient of the circuit to be detected, the wave impedance coefficient of the back side circuit and the wave impedance coefficient of the contralateral circuit;
the buses at two ends of the to-be-tested line are corresponding buses at two end points of the to-be-tested line;
the wave head amplitude calculation module is respectively connected with the refraction and reflection coefficient calculation module and the amplitude comparator, and is used for obtaining the amplitude of the refraction and reflection wave head of the initial wave head according to the current refraction and reflection coefficient of the fault point, the current refraction and reflection coefficient of the bus at the two ends of the line to be tested, the current refraction and reflection coefficient of the bus at the back side and the current refraction and reflection coefficient of the bus at the opposite side.
3. The traveling wave ranging locking time testing system according to claim 2, wherein the refraction-reflection coefficient calculating module comprises a fault point current refraction-reflection coefficient calculating unit, a first type bus current refraction-reflection coefficient calculating unit, a second type bus current refraction-reflection coefficient calculating unit and a third type bus current refraction-reflection coefficient calculating unit which are respectively connected with the data collector and the wave head amplitude calculating module;
the first type of bus is a bus with one-circuit outgoing line, the second type of bus is a bus with two-circuit outgoing lines, and the third type of bus is a bus with three-circuit outgoing lines and more than three-circuit outgoing lines;
the fault point current refraction and reflection coefficient calculation unit is used for obtaining the current refraction and reflection coefficient of the fault point according to the wave impedance coefficient of the line to be tested;
the first-type bus current refraction and reflection coefficient calculation unit is used for obtaining the current refraction and reflection coefficient of the first-type bus according to the wave impedance coefficient of the to-be-detected line, the wave impedance coefficient of the back-side line and the wave impedance coefficient of the opposite-side line;
the second class bus current refraction and reflection coefficient calculation unit is used for obtaining the current refraction and reflection coefficient of the second class bus according to the wave impedance coefficient of the to-be-detected line, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
The third bus current refraction and reflection coefficient calculation unit is used for obtaining the current refraction and reflection coefficient of the third bus according to the wave impedance coefficient of the to-be-detected line, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
the current refraction and reflection coefficients of the buses at the two ends of the line to be tested respectively correspond to the current refraction and reflection coefficients of the first type buses, the current refraction and reflection coefficients of the second type buses or the current refraction and reflection coefficients of the third type buses which are the same as the current refraction and reflection coefficients of the first type buses; the current refraction and reflection coefficient of the back side bus corresponds to the current refraction and reflection coefficient of a first bus, the current refraction and reflection coefficient of a second bus or the current refraction and reflection coefficient of a third bus which are the same with the back side bus; the current refraction and reflection coefficients of the opposite side buses correspond to the current refraction and reflection coefficients of the first type buses, the second type buses or the third type buses which are the same in type.
4. The traveling wave ranging lock-out time test system according to claim 2, wherein the wave head amplitude calculation module includes an intra-zone fault amplitude calculation unit, a forward extra-zone fault amplitude calculation unit, and a reverse extra-zone fault amplitude calculation unit connected to the refraction-reflection coefficient calculation module and the amplitude comparator, respectively;
The in-zone fault amplitude calculation unit is used for obtaining the amplitude of a refraction-reflection wave head during in-zone faults according to the current refraction-reflection coefficient of the fault point, the current refraction-reflection coefficient of the bus at the two ends of the line to be tested, the current refraction-reflection coefficient of the back bus and the current refraction-reflection coefficient of the opposite bus;
the positive out-of-zone fault amplitude calculation unit is used for obtaining the amplitude of the refraction-reflection wave head during the positive out-of-zone fault according to the current refraction-reflection coefficient of the fault point, the current refraction-reflection coefficient of the bus at the two ends of the line to be tested, the current refraction-reflection coefficient of the back bus and the current refraction-reflection coefficient of the opposite bus;
the reverse region external fault amplitude calculating unit is used for obtaining the amplitude of the refraction and reflection wave head during the reverse region external fault according to the current refraction and reflection coefficient of the fault point, the current refraction and reflection coefficient of the bus at the two ends of the line to be tested, the current refraction and reflection coefficient of the back side bus and the current refraction and reflection coefficient of the opposite side bus.
5. The traveling wave ranging lock-out time test system according to claim 1, wherein the first lock-out time calculator includes an addition operation module and a division operation module;
The addition operation module is respectively connected with the data memory and the amplitude comparator, and is used for obtaining the total length of the line propagated when the first refraction-reflection wave head reaches the first end of the line to be tested according to the length of the line to be tested, the length of the back side line and the length of the opposite side line;
the division operation module is respectively connected with the data memory and the addition operation module, and is used for obtaining the time used by the first refraction and reflection wave head when reaching the first end of the line to be tested according to the propagation speed of the traveling wave and the total length of the line propagated when the first refraction and reflection wave head reaches the first end of the line to be tested, wherein the time is a first locking time.
6. The method for testing the traveling wave ranging locking time is characterized by comprising the following steps of:
step S1: storing the length of the line to be measured, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave;
step S2: collecting the wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
step S3: obtaining the amplitude of the refraction-reflection wave head of the initial wave head according to the acquired wave impedance coefficient of the to-be-detected line, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line;
Step S4: comparing the amplitude of the refraction-reflection wave head with a preset threshold value;
step S5: selecting a catadioptric wave head which reaches the first end of the line to be tested at the latest from the catadioptric wave heads with the amplitude value being greater than or equal to the threshold value, and obtaining a first catadioptric wave head; obtaining the time used by the first refraction-reflection wave head when reaching the first end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is a first locking time;
the testing method of the traveling wave ranging locking time further comprises the following steps:
selecting a catadioptric wave head which reaches the second end of the line to be tested at the latest from the catadioptric wave heads with the amplitude value being greater than or equal to the threshold value, and obtaining a second catadioptric wave head; obtaining the time for the second refraction-reflection wave head to reach the second end of the line to be tested according to the length of the line to be tested, the length of the back side line, the length of the opposite side line and the propagation speed of the traveling wave, wherein the time is a second locking time;
judging whether the first locking time is greater than or equal to the second locking time, if so, the travelling wave ranging locking time is the first locking time; if not, the traveling wave ranging locking time is the second locking time.
7. The method for testing traveling wave ranging locking time according to claim 6, wherein the step S3 specifically includes:
step S31: according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line, the current refraction and reflection coefficients of the fault point, the current refraction and reflection coefficients of the buses at the two ends of the line to be tested, the current refraction and reflection coefficients of the back side bus and the opposite side bus are respectively obtained;
the buses at two ends of the to-be-tested line are corresponding buses at two end points of the to-be-tested line;
step S32: and obtaining the amplitude of the catadioptric wave head of the initial wave head according to the obtained current catadioptric coefficient of the fault point, the current catadioptric coefficients of the buses at the two ends of the line to be tested, the current catadioptric coefficient of the bus at the back side and the current catadioptric coefficient of the bus at the opposite side.
8. The method for testing traveling wave ranging locking time according to claim 7, wherein the step S31 specifically comprises:
obtaining a current refraction and reflection coefficient of a fault point according to the acquired wave impedance coefficient of the line to be tested through a formula (1), wherein the current refraction and reflection coefficient of the fault point comprises a current refraction coefficient alpha of the fault point F And the current reflection coefficient beta of the fault point F ；
Wherein Z is 1 And Z 0 Line mode impedance and zero mode impedance of unit length of line respectively, R f Is a fault transition resistance;
obtaining a current refraction and reflection coefficient of a first type bus according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line through a formula (2), wherein the current refraction and reflection coefficient of the first type bus comprises a current refraction and reflection coefficient alpha of the first type bus ZC And the current reflection coefficient beta of the first type bus bar ZC ；
Wherein C is the stray capacitance of the bus, Z is the wave impedance of the unit length of the line, and omega is the angular frequency;
obtaining the traveling wave from the wave impedance Z according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line by the formula (3) i Is transmitted to the wave impedance Z j A current refraction coefficient of a second type bus, wherein the current refraction coefficient of the second type bus comprises a current refraction coefficient alpha of the second type bus ij And the second type bus barIs the current reflection coefficient beta of (2) ij ；
Obtaining the traveling wave from the wave impedance Z according to the acquired wave impedance coefficient of the line to be tested, the wave impedance coefficient of the back side line and the wave impedance coefficient of the opposite side line by the formula (4) m Is transmitted to the wave impedance Z n A current refraction coefficient of a third class bus bar, wherein the current refraction coefficient of the third class bus bar comprises a current refraction coefficient alpha of the third class bus bar mn And the current refraction and reflection coefficient beta of the third bus bar mn ；
Wherein Z is Σ Equivalent impedance of a line connected with the third bus;
the current refraction and reflection coefficients of the buses at the two ends of the line to be tested respectively correspond to the current refraction and reflection coefficients of the first type buses, the current refraction and reflection coefficients of the second type buses or the current refraction and reflection coefficients of the third type buses which are the same as the current refraction and reflection coefficients of the first type buses; the current refraction and reflection coefficient of the back side bus corresponds to the current refraction and reflection coefficient of the first bus, the current refraction and reflection coefficient of the second bus or the current refraction and reflection coefficient of the third bus which are the same with the back side bus; the current refraction and reflection coefficients of the opposite side buses correspond to the current refraction and reflection coefficients of the first type buses, the current refraction and reflection coefficients of the second type buses or the current refraction and reflection coefficients of the third type buses, which are the same in type.
9. The method for testing traveling wave ranging locking time according to claim 7, wherein the step S32 specifically includes:
Obtaining the amplitude of the refraction-reflection wave head during the fault in the area according to the obtained current refraction-reflection coefficient of the fault point, the current refraction-reflection coefficient of the bus at the two ends of the line to be tested, the current refraction-reflection coefficient of the bus at the back side and the current refraction-reflection coefficient of the bus at the opposite side;
obtaining the amplitude of the refraction-reflection wave head when the fault occurs outside the forward region according to the obtained current refraction-reflection coefficient of the fault point, the current refraction-reflection coefficient of the bus at the two ends of the line to be tested, the current refraction-reflection coefficient of the bus at the back side and the current refraction-reflection coefficient of the bus at the opposite side;
and obtaining the amplitude of the catadioptric wave head in the case of the fault outside the reverse region according to the obtained current catadioptric coefficient of the fault point, the current catadioptric coefficients of the buses at the two ends of the line to be tested, the current catadioptric coefficient of the bus at the back side and the current catadioptric coefficient of the bus at the opposite side.
10. The method for testing traveling wave ranging locking time according to claim 6, wherein the step S5 specifically includes:
step S51: obtaining the total length of the line propagated when the first refraction-reflection wave head reaches the first end of the line to be measured according to the stored length of the line to be measured, the length of the back side line and the length of the opposite side line;
Step S52: and obtaining the time used by the first refraction-reflection wave head when reaching the first end of the line to be tested according to the stored propagation speed of the traveling wave and the total length of the line propagated when the first refraction-reflection wave head reaches the first end of the line to be tested, wherein the time is the first locking time.
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