CN115372757A - Power distribution network cable fault location method and system based on wide area earth wire current amplitude ratio - Google Patents
Power distribution network cable fault location method and system based on wide area earth wire current amplitude ratio Download PDFInfo
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Abstract
The invention discloses a power distribution network cable fault location method based on wide area earth wire current amplitude ratio, which comprises the following steps: judging a fault cable by comparing the polarities of the transient grounding line currents; calculating the ratio of the actually measured amplitude values of the currents of the grounding wires of the fault cable and the sound cable; setting virtual fault points by using a dichotomy method, and calculating the power frequency component of the grounding wire current of the head end of each branch cable; after a new fault interval is determined, reducing by using a dichotomy until a fault distance is obtained; and taking the average value of the plurality of fault distances as the final fault distance. The invention belongs to the technical field of power distribution network fault location, and particularly provides a power distribution network cable fault location method and a system for a wide-area earth wire current amplitude ratio, which are used in a power distribution network cable line, can realize unbalanced fault identification of a power distribution network, do not need accurate and synchronous signals, are not influenced by fault transition resistance and environmental noise, and can effectively improve the power supply reliability of the power distribution network.
Description
Technical Field
The invention belongs to the technical field of power distribution network fault location, and particularly relates to a power distribution network cable fault location method and system based on wide area earth wire current amplitude ratio.
Background
With the continuous development of power distribution systems and the continuous improvement of urbanization levels, the proportion of cable lines is continuously improved. Due to self-aging, external stress and other factors, the failure rate of the cable gradually rises, wherein single-phase metallic earth faults are the main factors. Due to the fact that the cable laying path is complicated, the fault cannot be found through an intuitive method after the fault occurs. The grounding fault point of the three-core cable is quickly and accurately positioned, the damage caused by the fault can be effectively reduced, and the power supply reliability of a power distribution system is ensured.
The existing power distribution network cable single-phase earth fault distance measuring method can be roughly divided into two categories: off-line and on-line methods. Although the off-line method is simple to implement and has high ranging accuracy, a fault point cannot be located in time, and a mode of externally injecting a signal may cause secondary damage to a cable. In contrast, the online fault location technology is faster and more efficient, and is mainly classified into a traveling wave method, an impedance method and a machine learning method. However, the power distribution network topology is complex, the line is short, the problem of superposition of traveling wave signals is serious, effective extraction and identification cannot be carried out, and the traveling wave method is limited in practical application. The machine learning method mainly researches artificial intelligence and is mainly characterized in that fault events are matched with cases trained before faults, and the method is simple to operate when faults are located, but needs a large amount of calculation. Most of the current impedance methods do not consider the influence of a metal shielding layer, and the positioning accuracy is poor. In the engineering practice, most of the existing terminals are difficult to obtain zero sequence voltage signals, and the zero sequence current acquisition can introduce considerable errors to distance measurement due to inaccurate measurement.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides the power distribution network cable fault distance measuring method and system which are used in a power distribution network cable line, can realize the identification of the unbalanced fault of the power distribution network, do not need accurate and synchronous signals, are not influenced by fault transition resistance and environmental noise, and can effectively improve the power supply reliability of the power distribution network.
The technical scheme adopted by the invention is as follows: the invention discloses a power distribution network cable fault location method based on wide area earth wire current amplitude ratio, which comprises the following steps:
s1: acquiring a current signal of a grounding wire at the head end of the cable, and judging a fault cable by comparing the polarities of the transient grounding wire currents of different cables;
s2: extracting power frequency components of 3 rd to 4 th power frequency cycles of the grounding line current of each branch cable after the fault, and calculating the actually measured amplitude ratio of the grounding line current of the fault cable to the grounding line current of the healthy cable one by one;
s3: setting virtual fault points on the fault cables by using a dichotomy, constructing a fault positioning equation by combining a power distribution network topological structure and line parameters, and calculating current power frequency components of the grounding wires at the head ends of the branch cables;
s4: calculating the amplitude ratio of the current of the fault cable grounding wire and the current of the healthy cable grounding wire when the virtual fault occurs one by one, and comparing the amplitude ratio with the actually measured amplitude ratio to determine a new fault interval;
s5: continuously reducing the fault interval by utilizing a bisection method, and stopping iteration when the distance between the boundaries of the two intervals is less than or equal to the requirement of the distance measurement allowable error to obtain a fault distance;
s6: and after solving a positioning equation according to the current amplitude ratio of all fault cables to the ground wires of the sound cables, taking the average value of the fault distances as the final fault distance.
Further, in the step S1, a difference operation is performed on the signal of the first-end ground wire, and if the absolute value of the difference is greater than a set threshold, it is determined that a fault occurs; differential delta I of ground line current SG (k) The formula (2) is shown in the following formula (1):
ΔI SG (k)＝I SG (k+1)-I SG (k) (k =0, 1.., n) formula (1)
In the formula (1), I SG (k) The current of the grounding wire measured for the head end of each cable, and k is the number of sampling points;
the basis for the occurrence of a fault is as shown in equation (2):
|ΔI SG (k)|＞I f formula (2)
In the formula (2), | Δ I SG (k) I is the calculated absolute value of the current difference, I f Is a set threshold. The transient grounding line current of the fault cable is opposite to the transient grounding line current of the sound cable in polarity, and the fault cable is selected by comparing the polarities of the transient grounding line currents of different cables.
Wherein the threshold value I f The obtaining method comprises the following steps: based on the conditions of the simulation system, the switching of simulation equipment, the maximum unbalanced operation and the system disturbance, the maximum difference absolute value of the earth current under each condition is obtained, and the maximum value in the maximum difference absolute value is taken and recorded as I f 。
As a preferred scheme, extracting the power frequency component of the current of the grounding wire in the 3 rd to 4 th power frequency periods after the fault occurs by utilizing Fourier transform, and calculating the actual measurement amplitude ratio of the current of the grounding wire of the fault cable to the current of the grounding wire of the sound cable one by one;
measured amplitude ratio k fi The formula (3) is shown as follows:
in the formula (3), the reaction mixture is,
for the fault cable j to be the ground line current,
for a robust cable i ground current, N represents the number of distribution network cables.
Further, in the fault cable section [ a, b ] according to dichotomy](a =0, b = l) (l is the length of the faulty cable) and the midpoint α is taken within 1 And constructing a fault positioning equation by combining the topology of the power distribution network and line parameters such as resistance, inductance and capacitance, and solving the current of the grounding wire of each cable when the point has a fault.
As described in step S4, the current of the faulty cable ground wire and the current of the healthy cable ground wire are calculated one by one when the virtual fault occursAmplitude ratio k cfi (α 1 ) (ii) a Comparison k cfi (α 1 ) Current amplitude ratio k of ground wire to actually measured ground wire fi The size relationship of (1):
if k is cfi (α 1 )＝k fi Then l is fi ＝α 1 ；
If k is cfi (α 1 )<k fi Then the fault point is [ a, alpha ] 1 ]Let b = α 1 Then a new interval [ a, b ] is generated]；
If k is cfi (α 1 )>k fi Then the fault point is [ alpha ] 1 ,b]Let a = α 1 Then a new interval [ a, b ] is generated]；
The calculation formula of the current amplitude ratio of the cable grounding wire when the virtual fault occurs is shown as the formula (4):
in the formula (4), the reaction mixture is,
for the calculated fault cable j ground current,
the calculated healthy cable i ground current.
Further, the fault interval is continuously reduced by utilizing a bisection method, iteration is stopped when the distance between the boundaries of the two intervals is smaller than or equal to the requirement of the distance measurement allowable error epsilon, namely b-a is smaller than or equal to epsilon, and the fault distance l is obtained fi = (a + b)/2; after the current amplitude ratio of all fault cables to the ground wire of the sound cable is solved and the positioning equation is completed, the final fault distance is
Wherein, the allowable error epsilon is selected according to actual needs.
As a further elaboration scheme, the invention also discloses a power distribution network cable fault location system with wide area earth wire current amplitude ratio:
the ground wire current collection device comprises a plurality of ground wire current collection devices, an information collection device, a data processing device, a communication network and a memory;
the grounding wire current acquisition device is arranged at the head end of each cable and is used for acquiring the current of the grounding wire at the head end;
the information collecting device collects the data recorded by the grounding wire current collecting device in the coverage area of the information collecting device;
the data processing device is used for executing any step of the fault distance measuring method;
the communication network is used for connecting the grounding wire current acquisition device and the information collecting device with the data processing device in a communication way;
the memory is used for storing instructions and fault data.
The beneficial effects obtained by adopting the scheme are as follows: according to the method and the system for measuring the distance of the power distribution network cable fault based on the wide area earth wire current amplitude ratio, the unbalanced fault of the power distribution network is identified according to the obvious mutation characteristic of the earth wire current after the fault based on the research on the earth wire current characteristic of the metal shielding layer, and the precision is high; the distance measurement equation is constructed by adopting the current amplitude ratio of the grounding wires of the whole network, so that the influence of the transition resistance on the distance measurement precision is effectively eliminated; compared with some existing ranging methods, the method requires low signal sampling rate and does not need precise synchronization; the method is not influenced by environmental noise, three-phase imbalance and topology change of the power distribution network, and the distance measurement precision is high; the current of the grounding wire can be conveniently measured at the head end of the cable through the current transformer, so that the errors caused by field measurement conditions, the limitation of the volume of signal acquisition equipment and data synthesis are avoided, the implementation cost is low, and the method has the condition of popularization and application in engineering.
Drawings
In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the present disclosure taken in conjunction with the accompanying drawings, in which:
fig. 1 is an overall flowchart of a power distribution network cable fault location method for wide area ground line current amplitude ratio according to the present invention;
fig. 2 is a diagram showing a simulation of a cable line of a power distribution network in embodiment 3;
FIG. 3 is the ground line current for different outgoing lines simulated in example 3;
FIG. 4 shows a fault line L 1 And healthy line L 4 The head end ground line current and the ratio of the two;
fig. 5 shows ranging results under different fault conditions.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
As shown in fig. 1, the method for measuring the distance between the power distribution network cable faults by using the wide area ground wire current amplitude ratio of the invention comprises the following steps:
s1: acquiring a current signal of a grounding wire at the head end of the cable, and judging a fault cable by comparing the polarities of the transient grounding wire currents of different cables;
carrying out differential operation on signals of the ground wire at the head end, and judging that a fault occurs if the absolute value of the difference is greater than a set threshold value; differential delta I of ground line current SG (k) The formula (2) is shown in the following formula (1):
ΔI SG (k)＝I SG (k+1)-I SG (k) (k =0, 1.., n) formula (1)
In the formula (1), I SG (k) The current of the grounding wire measured for the head end of each cable, and k is the number of sampling points;
the basis for the occurrence of a fault is as shown in equation (2):
|ΔI SG (k)|＞I f formula (2)
In the formula (2), | Δ I SG (k) I is the calculated absolute value of the current difference, I f Is a set threshold. The transient grounding line current of the fault cable is opposite to the transient grounding line current of the sound cable in polarity, and the fault cable is selected by comparing the polarities of the transient grounding line currents of different cables.
Wherein the threshold value I f The obtaining method comprises the following steps: based on the conditions of the simulation system, the switching of simulation equipment, the maximum unbalanced operation and the system disturbance, the maximum difference absolute value of the earth current under each condition is obtained, and the maximum value in the maximum difference absolute value is taken and recorded as I f 。
S2: extracting power frequency components of 3 rd to 4 th power frequency cycles of the grounding line current of each branch cable after the fault, and calculating the actually measured amplitude ratio of the grounding line current of the fault cable to the grounding line current of the healthy cable one by one;
extracting power frequency components of the current of the grounding wire in the 3 rd to 4 th power frequency periods after the fault occurs by utilizing Fourier transform, and calculating the actually measured amplitude ratio of the current of the grounding wire of the fault cable to the current of the grounding wire of the healthy cable one by one;
measured amplitude ratio k fi The formula (3) is shown as follows:
in the formula (3), the reaction mixture is,
for the fault cable j to be grounded,
for a healthy cable i earth wire current, N represents the number of distribution network cables.
S3: setting virtual fault points on the fault cables by using a dichotomy, constructing a fault positioning equation by combining a power distribution network topological structure and line parameters, and calculating the power frequency component of the current of the grounding wire at the head end of each branch cable;
according to dichotomy in fault cable sections [ a, b](a =0, b = l) (l is the length of the faulty cable) and the midpoint α is taken within 1 And constructing a fault positioning equation by combining the topology of the power distribution network and line parameters such as resistance, inductance and capacitance, and solving the current of the grounding wire of each cable when the point has a fault.
S4: calculating the amplitude ratio of the current of the fault cable earth wire to the current of the healthy cable earth wire when the virtual fault occurs one by one, and comparing the amplitude ratio with the actually measured amplitude ratio to determine a new fault interval;
calculating the amplitude ratio k of the current of the fault cable earth wire to the current of the sound cable earth wire when the virtual fault occurs one by one cfi (α 1 ) (ii) a Comparison k cfi (α 1 ) Current amplitude ratio k of ground wire to actually measured ground wire fi The size relationship of (1):
if k is cfi (α 1 )＝k fi Then l is fi ＝α 1 ；
If k is cfi (α 1 )<k fi Then the fault point is [ a, α ] 1 ]Let b = α 1 Then a new interval [ a, b ] is generated]；
If k is cfi (α 1 )>k fi Then the fault point is [ alpha ] 1 ,b]Let a = α 1 Then a new interval [ a, b ] is generated]；
The calculation formula of the current amplitude ratio of the cable earth wire when the virtual fault occurs is shown as the formula (4):
in the formula (4), the reaction mixture is,
for the calculated fault cable j ground current,
the resulting healthy cable i ground current is calculated.
S5: continuously reducing the fault interval by utilizing a bisection method, and stopping iteration when the distance between the boundaries of the two intervals is less than or equal to the requirement of the distance measurement allowable error to obtain a fault distance;
s6: and after the current amplitude ratio of all fault cables to the healthy cable grounding wire is solved and the positioning equation is completed, taking the average value of the fault distances as the final fault distance.
Continuously reducing the fault interval by using a bisection method, stopping iteration when the distance between the boundaries of the two intervals is less than or equal to the requirement of the distance measurement allowable error epsilon, namely b-a is less than or equal to epsilon, and obtaining the fault distance l fi = (a + b)/2; after the current amplitude ratio of all fault cables to the ground wire of the sound cable is solved and the positioning equation is completed, the final fault distance is
Wherein, the allowable error epsilon is selected according to actual needs.
Example 2
Based on the same inventive concept as embodiment 1, the embodiment of the present invention provides a power distribution network cable fault location system with a wide area ground wire current amplitude ratio, including:
the device comprises a plurality of grounding wire current acquisition devices, an information collection device, a data processing device, a communication network and a memory;
the grounding wire current acquisition device is arranged at the head end of each cable and is used for acquiring the current of a grounding wire at the head end;
the information collecting device collects the data recorded by the grounding wire current collecting device in the coverage area of the information collecting device;
the data processing device is used for executing any step of the fault distance measuring method;
the communication network is used for connecting the grounding wire current acquisition device, the information collection device and the data processing device in a communication way;
the memory is used for storing instructions and fault data.
Example 3
In order to verify the model and the ranging algorithm, a simulation model of a 10kV neutral point arc suppression coil grounding power distribution network is constructed based on PSCAD/EMTDC and is shown in FIG. 2. The simulation model contains 8 cables, of which the line L 7 And the other lines are put into operation in a standby state. The sampling frequency was 6.4kHz.
FIG. 3 shows simulated ground line currents for different outgoing lines, where I G_S_L1 For faulty cable L 1 Head end earth line current of G_S_L2 、I G_S_L4 、I G_S_L5 Respectively a sound line L 2 、L 4 、L 5 The head end ground line current of (1). FIG. 4 shows a fault line L 1 And healthy line L 4 And the ratio of the head end ground line current to the head end ground line current.
Fig. 5 shows the ranging results under different fault conditions, and it can be seen that the power distribution network cable fault ranging method of the wide area earth line current amplitude ratio provided by the present invention has higher accuracy under different fault resistances, different fault initial phase angles and different fault positions.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
The present invention and its embodiments have been described above, and the description is not intended to be limiting, and the drawings are only one embodiment of the present invention, and the actual structure is not limited thereto. In summary, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. The power distribution network cable fault location method of the wide area earth wire current amplitude ratio is characterized by comprising the following steps of:
s1: acquiring a current signal of a grounding wire at the head end of the cable, and judging a fault cable by comparing the polarities of the transient grounding wire currents of different cables;
s2: extracting power frequency components of 3 rd to 4 th power frequency cycles of the grounding line current of each branch cable after the fault, and calculating the actually measured amplitude ratio of the grounding line current of the fault cable to the grounding line current of the healthy cable one by one;
s3: setting virtual fault points on the fault cables by using a dichotomy, constructing a fault positioning equation by combining a power distribution network topological structure and line parameters, and calculating current power frequency components of the grounding wires at the head ends of the branch cables;
s4: calculating the amplitude ratio of the current of the fault cable grounding wire and the current of the healthy cable grounding wire when the virtual fault occurs one by one, and comparing the amplitude ratio with the actually measured amplitude ratio to determine a new fault interval;
s5: continuously reducing the fault interval by using a bisection method, and stopping iteration when the distance between the boundaries of the two intervals is less than or equal to the requirement of the distance measurement allowed error to obtain a fault distance;
s6: and after solving a positioning equation according to the current amplitude ratio of all fault cables to the ground wires of the sound cables, taking the average value of the fault distances as the final fault distance.
2. The method of claim 1, wherein the wide area ground wire current magnitude ratio is a power distribution network cable fault location method, the method comprising: in the step S1, differential operation is carried out on signals of the grounding wire at the head end, and if the absolute value of the difference is greater than a set threshold value, a fault is determined to occur; differential delta I of ground line current SG (k) The formula (2) is shown in the following formula (1):
ΔI SG (k)＝I SG (k+1)-I SG (k) (k =0, 1.., n) formula (1)
In the formula (1), I SG (k) The current of the grounding wire measured for the head end of each cable, and k is the number of sampling points;
the basis for the occurrence of a fault is as shown in equation (2):
|ΔI SG (k)|＞I f formula (2)
In the formula (2), | Δ I SG (k) I is the calculated absolute value of the current difference, I f Is a set threshold.
3. The method of claim 2, wherein the wide area ground wire current magnitude ratio is a power distribution network cable fault location method, the method comprising: the transient earth wire current of the fault cable is opposite to the transient earth wire current of the sound cable in polarity, and the fault cable is selected by comparing the polarities of the transient earth wire currents of different cables.
4. The method of claim 3, wherein the wide area ground wire current magnitude ratio is determined by a power distribution network cable fault location method, comprising: extracting power frequency components of the current of the grounding wire in the 3 rd to 4 th power frequency periods after the fault occurs by utilizing Fourier transform, and calculating the actually measured amplitude ratio of the current of the grounding wire of the fault cable to the current of the grounding wire of the healthy cable one by one;
measured amplitude ratio k fi The formula (3) is shown as follows:
in the formula (3), the reaction mixture is,
for the fault cable j to be the ground line current,
for a robust cable i ground current, N represents the number of distribution network cables.
5. The method of claim 4, wherein the wide area ground wire current magnitude ratio is determined by a power distribution network cable fault location method, comprising: according to dichotomy in fault cable sections [ a, b](a =0, b = l) (l is the length of the faulty cable) and the midpoint α is taken within 1 Combined with distribution of electricityAnd constructing a fault positioning equation by using the network topology and the parameters of the resistor, the inductor and the capacitor, and solving the current of the grounding wire of each cable when the point has a fault.
6. The method of claim 5, wherein the wide area ground wire current magnitude ratio is determined by a method comprising: calculating the amplitude ratio k of the current of the fault cable earth wire to the current of the sound cable earth wire when the virtual fault occurs one by one cfi (α 1 ) (ii) a Comparison k cfi (α 1 ) Current amplitude ratio k of ground wire to actual measurement fi The size relationship of (1):
if k is cfi (α 1 )＝k fi Then l is obtained fi ＝α 1 ；
If k is cfi (α 1 )<k fi Then the fault point is [ a, α ] 1 ]Let b = α 1 Then a new interval [ a, b ] is generated]；
If k is cfi (α 1 )>k fi Then the fault point is [ alpha ] 1 ,b]Let a = α 1 Then a new interval [ a, b ] is generated]；
The calculation formula of the current amplitude ratio of the cable earth wire when the virtual fault occurs is shown as the formula (4):
in the formula (4), the reaction mixture is,
to calculate the resulting fault cable j ground current,
the resulting healthy cable i ground current is calculated.
7. The method of claim 6, wherein the wide area ground wire current magnitude ratio is determined by a method comprising: continuously reduce the power by dichotomyStopping iteration when the distance between the boundaries of the two intervals is less than or equal to the requirement of the distance measurement allowable error epsilon, namely b-a is less than or equal to epsilon, and obtaining the fault distance l fi = (a + b)/2; after the current amplitude ratio of all fault cables to the healthy cable grounding wire is solved and the positioning equation is completed, the final fault distance is as shown in the formula (5):
8. the method of claim 2, wherein the threshold I is a wide area ratio of ground line current magnitude for cable fault location in a power distribution network f The obtaining method comprises the following steps: based on the conditions of simulation system, simulation equipment switching, maximum unbalanced operation and system disturbance, the maximum difference absolute value of the earth wire current under each condition is obtained, and the maximum value in the maximum difference absolute value is taken as I f 。
9. The method of claim 7, wherein the wide area ground wire current magnitude ratio is determined by a method comprising: the allowable error epsilon is selected according to actual needs.
10. A fault location system for a power distribution network cable fault location method of wide area earth wire current magnitude ratio according to any of claims 1-9, wherein:
the ground wire current collection device comprises a plurality of ground wire current collection devices, an information collection device, a data processing device, a communication network and a memory;
the grounding wire current acquisition device is arranged at the head end of each cable and is used for acquiring the current of the grounding wire at the head end;
the information collecting device collects the data recorded by the grounding wire current collecting device in the coverage area of the information collecting device;
the data processing apparatus is adapted to perform the steps of the method of any one of claims 1 to 9;
the communication network is used for connecting the grounding wire current acquisition device and the information collecting device with the data processing device in a communication way;
the memory is used for storing instructions and fault data.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1089081A2 (en) * | 1999-09-23 | 2001-04-04 | ABB Substation Automation Oy | Method for computational determination of ground fault distance in an electrical power distribution network having a ring configuration |
| KR20020017390A (en) * | 2000-08-30 | 2002-03-07 | 이승재 | Apparatus and method for locating fault distance in a power double circuit transmision line |
| CN113093050A (en) * | 2021-03-31 | 2021-07-09 | 中国矿业大学 | Cable early fault identification method and system based on cable grounding wire current time-frequency characteristics |
| CN113655342A (en) * | 2021-09-23 | 2021-11-16 | 国网江苏省电力有限公司连云港供电分公司 | Three-core cable single-phase fault positioning method based on multi-conductor coupling model |
| CN113805012A (en) * | 2021-09-23 | 2021-12-17 | 国网江苏省电力有限公司连云港供电分公司 | Method for identifying fault section of power distribution network with neutral point grounded through small resistor |
| CN114487698A (en) * | 2021-12-31 | 2022-05-13 | 中国矿业大学 | Power distribution network cable fault positioning method and system based on current amplitude ratio of double-end grounding wire |
| CN114779007A (en) * | 2022-04-20 | 2022-07-22 | 中国矿业大学 | Distribution cable fault section positioning method based on earth wire current and zero sequence current |
-
2022
- 2022-08-30 CN CN202211043974.9A patent/CN115372757A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1089081A2 (en) * | 1999-09-23 | 2001-04-04 | ABB Substation Automation Oy | Method for computational determination of ground fault distance in an electrical power distribution network having a ring configuration |
| KR20020017390A (en) * | 2000-08-30 | 2002-03-07 | 이승재 | Apparatus and method for locating fault distance in a power double circuit transmision line |
| CN1359010A (en) * | 2000-08-30 | 2002-07-17 | 株式会社赛尔鲍尔 | Apparatus and method for positioning parallel double electricity transmission line |
| CN113093050A (en) * | 2021-03-31 | 2021-07-09 | 中国矿业大学 | Cable early fault identification method and system based on cable grounding wire current time-frequency characteristics |
| CN113655342A (en) * | 2021-09-23 | 2021-11-16 | 国网江苏省电力有限公司连云港供电分公司 | Three-core cable single-phase fault positioning method based on multi-conductor coupling model |
| CN113805012A (en) * | 2021-09-23 | 2021-12-17 | 国网江苏省电力有限公司连云港供电分公司 | Method for identifying fault section of power distribution network with neutral point grounded through small resistor |
| CN114487698A (en) * | 2021-12-31 | 2022-05-13 | 中国矿业大学 | Power distribution network cable fault positioning method and system based on current amplitude ratio of double-end grounding wire |
| CN114779007A (en) * | 2022-04-20 | 2022-07-22 | 中国矿业大学 | Distribution cable fault section positioning method based on earth wire current and zero sequence current |
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