WO2019174045A1

WO2019174045A1 - Method and device for locating fault point in area network based on traveling wave

Info

Publication number: WO2019174045A1
Application number: PCT/CN2018/079329
Authority: WO
Inventors: Xin Dong Li; Xi Xia DU; Ke Hu
Original assignee: Siemens Aktiengesellschaft
Priority date: 2018-03-16
Filing date: 2018-03-16
Publication date: 2019-09-19
Also published as: CN111433617A; CN111433617B; BR112020018356A2

Abstract

The present invention relates to a method and device for locating a fault point in an area network based on a traveling wave, the area network including a plurality of transformer substations, and every two adjacent transformer substations being connected via a power line. The method includes: if a power line has a fault point, acquiring a time point set, the time point set including time points of arrival of a traveling wave corresponding to the fault point at each transformer substation; acquiring a location set, the location information set including location information about each transformer substation; determining a transformer substation from the area network to serve as an initial target point; determining a plurality of transformer substations from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point; determining a first distance between the fault point and the target point according to the time point set, the location set and the reference points; and determining the location of the fault point according to the first distance. According to the present invention, a fault point can be accurately located.

Description

METHOD AND DEVICE FOR LOCATING FAULT POINT IN AREA NETWORK BASED ON TRAVELING WAVE

BACKGROUND Technical Field

The present invention relates to the field of power, and more particularly to a method and device for locating a fault point in an area network based on a traveling wave.

Related Art

Power is a basis of national economy and is an important pillar industry. Therefore, a power system must be safe and reliable. The power system generally consists of generators, a transformers, buss, power lines, and electric equipments. Each electrical element and system are in a normal running state usually, but may be in a faulty or abnormal running state.

With the increasingly-expanded scale and increasingly-complex structure of the power system, a fault is inevitable. Particularly, due to a large distribution range of the power line, the power line is usually affected by various complex geographical environments and climatic environments, and a running fault of the power line caused by adverse environment conditions will directly affect safe and reliable running of the power line or even may cause a large-area power outage if the fault is serious. Thus, when the power line is faulty, it is necessary to rapidly determine the corresponding fault point, for convenience of timely maintenance.

Therefore, it is urgently necessary to accurately determine a location of the fault point.

SUMMARY

In view of this, the present invention is directed to a method and device for locating a fault point in an area network based on a traveling wave, so as to accurately locate a fault point.

According to one aspect of the present invention, a method for locating a fault point in an area network based on a traveling wave is provided, the area network including a plurality of transformer substations, and every two adjacent transformer substations being connected via a power line. The method includes:

if a power line has a fault point , acquiring a time point set, the time point set including time points of arrival of a traveling wave corresponding to the fault point at each transformer substation;

acquiring a location set, the location information set including location information about each transformer substation;

determining a transformer substation from the area network to serve as an initial target point;

determining a plurality of transformer substations from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point;

determining a first distance between the fault point and the target point according to the time point set, the location set and the reference points; and

determining a location of the fault point according to the first distance.

After a fault point of a power line is recognized, time of arrival of a traveling wave at a plurality of transformer substations is acquired, an initial target point and a plurality of reference points are determined, the location of the fault point is determined by combining traveling wave time received by the plurality of transformer substations in the same area network, a location set of the plurality of transformer substations and the plurality of reference points, and therefore the location of the fault point can be more accurately determined. Furthermore, the method of the present embodiment does not determine the location of the fault point by means of a wave speed of the traveling wave, thereby avoiding an inaccurate final locating result caused by a possible change of the wave speed.

According to the foregoing method, alternatively, determining the first distance between the fault point and the target point according to the time point set, the location set and the reference points includes:

determining a time interval between time of arrival of the traveling wave at the target point and at each reference point according to the time point set;

determining a second distance between the target point and each reference point according to the location set; and

determining the first distance between the fault point and the target point according to each time interval and each second distance.

According to the foregoing method, alternatively, determining one transformer substation from the area network to serve as the initial target point includes: determining one of transformer substations at two ends of the power line where the fault point is located to serve as the initial target point.

Because a traveling wave may be attenuated and traveling waves received by the transformer substations at the two ends of the power line where the fault point is located are relatively strong, detection results of the traveling waves are more accurate, and then final location of the fault point may be relatively accurate.

According to the foregoing method, alternatively, after determining the first distance between the fault point and the target point according to each time interval and each second distance, and before determining the location of the fault point according to the first distance, the method further includes:

determining another transformer substation from the area network to serve as an updated target point, and returning to execute the operation of determining a plurality of reference points from the remaining transformer substations until another first distance between the fault point and the updated target point is determined; and

correcting a first distance b/2 between the fault point and the initial target point according to a following formula:

b/2 = (the first distance plus a third distance between two transformer substations at two ends of a power line where the fault point is located minus the another first distance) /2.

Because distances between two target points are simultaneously involved in a corrected first distance, the fault point can be more accurately located.

According to the foregoing method, alternatively, the initial target point is one of transformer substations at two ends of the power line where the fault point is located, and the updated target point is the other one of the transformer substations at the two ends of the power line where the fault point is located.

According to the foregoing method, alternatively, determining the first distance between the fault point and the target point according to each time interval and each second distance includes:

determining a first distance b/2 between the fault point and the target point according to a following formula:

where X _i represents a time interval of arrival of the traveling wave at the i ^th reference point and time of arrival of the traveling wave at the target point, Y _i represents a second distance between the i ^th reference point and the target point, n represents the number of the reference points, both i and n are positive integers, a represents a negative of the wave speed of the traveling wave, and b is twice of the first distance between the fault point and the target point.

According to the foregoing method, alternatively, the traveling wave is a current traveling wave. The current traveling wave is easier to detect, and lowly requires a locating implementation device, and therefore the cost is relatively low.

According to the foregoing method, alternatively, a time point of arrival of the traveling wave at each transformer substation is a time point of arrival of a wave head of the traveling wave at each transformer substation.

According to another aspect of the present invention, a device for locating a fault point in an area network based on a traveling wave is provided, the area network including a plurality of transformer substations, and every two adjacent transformer substations being connected via a power line. The device includes:

a first acquisition unit, configured to acquire a time point set if a power line has a fault point, the time point set including time points of arrival of a traveling wave corresponding to the fault point at each transformer substation;

a second acquisition unit, configured to acquire a location set, the location information set including location information about each transformer substation;

a first determination unit, configured to determine a transformer substation from the area network to serve as an initial target point;

a second determination unit, configured to determine a plurality of transformer substations from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point;

a third determination unit, configured to determine a first distance between the fault point and the target point according to the time point set, the location set and the reference points; and

a fourth determination unit, configured to determine a location of the fault point according to the first distance.

After a fault point of a power line is recognized, time of arrival of a traveling wave at a plurality of transformer substations is acquired, an initial target point and a plurality of reference points are determined, the location of the fault point is determined by combining traveling wave time received by the plurality of transformer substations in the same area network, a location set of the plurality of transformer substations and a plurality of reference points, and therefore the location of the fault point can be more accurately determined. Furthermore, the method of the present embodiment does not determine the location of the fault point by means of a wave speed of the traveling wave, thereby avoiding a possibility of an inaccurate final locating result caused by a possible change of the wave speed.

According to the foregoing device, alternatively, the third determination unit specifically includes:

a time determination sub-unit, configured to determine a time interval between time of arrival of the traveling wave at the target point and at each reference point according to the time point set;

a first distance determination sub-unit, configured to determine a second distance between the target point and each reference point according to the location set; and

a second distance determination sub-unit, configured to determine the first distance between the fault point and the target point according to each time interval and each second distance.

According to the foregoing device, alternatively, the first determination unit is specifically configured to: determine one of transformer substations at two ends of the power line where the fault point is located to serve as an initial target point. Because a traveling wave may be attenuated and traveling waves received by the transformer substations at the two ends of the power line where the fault point is located are relatively strong, detection results of the traveling waves are more accurate, and then final location of the fault point may be relatively accurate.

The foregoing device, alternatively, further includes a correction unit, configured to:

determine another transformer substation from the area network to serve as an updated target point, and return to trigger the second determination unit until another first distance between the fault point and the updated target point is determined; and

correct the first distance b/2 between the fault point and the initial target point according to a following formula:

b/2= (the first distance plus a third distance between two transformer substations at two ends of a power line where the fault point is located minus the another first distance) /2.

According to the foregoing device, alternatively, the initial target point is one of transformer substations at two ends of the power line where the fault point is located, and the updated target point is the other one of the transformer substations at the two ends of the power line where the fault point is located.

According to the foregoing device, alternatively, the second distance determination sub-unit is specifically configured to:

determine a first distance b/2 between the fault point and the target point according to a following formula:

where X _i represents a time interval between time of arrival of the traveling wave at the i ^th reference point and time of arrival of the traveling wave at the target point, Y _i represents a second distance between the i ^th reference point and the target point, n represents the number of the reference points, both i and n are positive integers, a represents a negative of a wave speed of the traveling wave, and b is twice of the first distance between the fault point and the target point.

According to the foregoing device, alternatively, the traveling wave is a current traveling wave. The current traveling wave is easier to detect, and lowly requires a locating implementation device, and therefore the cost is relatively low.

According to the foregoing device, alternatively, a time point of arrival of the traveling wave at each transformer substation is a time point of arrival of a wave head of the traveling wave at each transformer substation.

According to a further aspect of the present invention, a device for locating a fault point in an area network based on a traveling wave is provided, the area network including a plurality of transformer substations, and every two adjacent transformer substations being connected via a power line. The device includes:

at least one communication interface, configured to communicate with each transformer substation;

at least one memory, configured to store location information about each transformer substation; and

at least one processor, connected to the communication interface and the memory, and acquiring data sent by the communication interface and the location information in the memory, the processor being configured to execute the method for locating a fault point in an area network based on a traveling wave according to any one of the preceding contents.

at least one memory, configured to store an instruction; and

at least one processor, configured to execute the method for locating a fault point in an area network based on a traveling wave by means of the instruction stored by the memory according to any one of the preceding contents.

According to a yet further aspect of the present invention, a readable storage medium is provided. A machine-readable instruction is stored in the readable storage medium stores a machine-readable instruction, and when the machine-readable instruction is executed by a machine, the machine executes the method for locating a fault point in an area network based on a traveling wave according to any one of the preceding contents.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described hereinbelow with reference to the drawings in detail to allow those ordinarily skilled in the art to more clearly understand the above-mentioned and other features and advantages of the present invention. In the drawings,

FIG. 1 is a flowchart of a method for locating a fault point in an area network based on a traveling wave according to an embodiment of the present invention.

FIG. 2 is a flowchart of a method for locating a fault point in an area network based on a traveling wave according to another embodiment of the present invention.

FIG. 3 is a structure diagram of an area network according to a further embodiment of the present invention.

FIG. 4 is a structure diagram of a device for locating a fault point in an area network based on a traveling wave according to a further embodiment of the present invention.

FIG. 5A is a structure diagram of a device for locating a fault point in an area network based on a traveling wave according to another embodiment of the present invention.

FIG. 5B is a structure diagram of a device for locating a fault point in an area network based on a traveling wave according to a further embodiment of the present invention.

FIG. 6 is a structure diagram of a device for locating a fault point in an area network based on a traveling wave according to a yet further embodiment of the present invention.

DETAILED DESCRIPTION

To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further illustrated with the following embodiments in detail.

An area network usually includes a plurality of transformer substations connected via a power line, that is, two transformer substations in direct communication are connected via a power line. All transformer substations falling within the same area network may directly or indirectly communicate with one another. Each transformer substation is provided with a relay protection device and a traveling wave detection device. It may be found out whether a power line is faulty in the area network by means of the relay protection device or the traveling wave detection device. For example, it can be found out whether a power line is faulty by means of a voltage or current change, or it can be determined whether a power line is faulty by detecting the presence or absence of a traveling wave. A specific mode of how to recognize whether a fault point occurs on a power line of an area network falls within the prior art, and will not be elaborated herein.

If a fault point of the power line of the area network is recognized, it is then necessary to determine a location of the fault point. The power line between two transformer substations is as long as tens of kilometers or even hundreds of kilometers generally. Therefore, it is necessary to determine a specific location of the fault point, for convenience of timely maintenance.

The present invention determines a specific location of a fault point by using traveling wave information received by each transformer substation in an area network and a location of each transformer substation, and therefore the fault point can be more accurately located.

The “first” and “second” in the following text do not represent the sequence, just for distinguishing.

Embodiment 1

The present embodiment provides a method for locating a fault point in an area network based on a traveling wave, an executive body being a device for locating a fault point in an area network based on a traveling wave. The device may communicate with a traveling wave detection device in the transformer substations, and may also communicate with a relay protection device in the transformer substations.

FIG. 1 shows a flowchart of a method for locating a fault point in an area network based on a traveling wave according to the present embodiment. The method includes the steps as follows.

Step 101, if a power line has a fault point, a time point set is acquired.

An area network includes a plurality of transformer substations connected via a power line. All transformer substations falling within the same area network may directly or indirectly communicate with one another.

The time point set includes time points of arrival of a traveling wave corresponding to the fault point at each transformer substation, i.e. the arrival time of the traveling wave at each transformer substation. The traveling wave detection device may detect a time point of arrival of a traveling wave at each transformer substation. The present embodiment, for example, selects a time point of first arrival of a traveling wave at each transformer substation. It should be noted that a manner of acquiring a time point set may be respectively receiving, by the device for locating a fault point in an area network based on a traveling wave, a time point sent by the traveling wave detection device in each transformer substation, or may be collecting, by another device, all time points into a time point set by another device and then sending the time point set to the device for locating the fault point in the area network based on the traveling wave, as long as it is ensured that a time point of arrival of a traveling wave corresponding to a fault point at each transformer substation can be acquired. For simple description, all time points of arrival of the traveling wave at each transformer substation are referred to as a "time point set" . The acquisition behavior may be actively initiated or may be passively received.

In the present embodiment, the relay protection device or the traveling detection device may be specifically adopted to determine whether a fault point occurs on a power line, and then the device for locating the fault point in the area network based on the traveling wave is informed. Or, after the relay protection device or the traveling detection device recognizes a fault point, the device for locating the fault point in the area network based on the traveling wave is directly triggered to execute an operation of acquiring the time point set. For example, the traveling wave detection device directly sends a time point of arrival of the traveling wave at a transformer substation to the device for locating the fault point in the area network based on the traveling wave.

Step 102, a location set is acquired, the location information set including location information about each transformer substation.

The location information about each transformer substation may be represented by longitude and latitude or may be represented by a basic reference, which may be selected specifically according to an actual requirement and will not be elaborated herein. The location set may be pre-stored in the device for locating the fault point in the area network based on the traveling wave, or may be pre-stored in a memory. As required, the device for locating a fault point in the area network based on the traveling wave may acquire the location set therefore. A specific implementation manner will not be elaborated any longer.

Step 103, a transformer substation is determined from the area network to serve as an initial target point, and a plurality of transformer substations is determined from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point.

The number of reference points should be at least two, i.e. there are at least two reference points.

In the present embodiment, any one transformer substation capable of detecting time of arrival of a traveling wave may be selected from the area network to serve as an initial target point, and a plurality of reference points is determined from the remaining transformer substations, wherein the number of the reference points may be selected according to an actual requirement. A transformer substation (the power line between the transformer substation and the target point needs to pass through the fault point) is an opposite transformer substation of the target point based on the fault point. The reference points may be opposite transformer substations partially or totally. When the reference points are opposite transformer substations totally, calculated amount may be simplified, thereby obtaining a final result more rapidly.

Step 104, a first distance between the fault point and the target point is determined according to the time point set, the location set and the reference points.

Step 105, a location of the fault point is determined according to the first distance.

Because the location of the target point and the layout direction of the power line have been known in advance, the location of the fault point can be directly determined after acquiring the locations of the fault point and the target point. Staff may directly arrive at the location of the fault point to perform maintenance. Certainly, the staff may also start from the target point, walk for a length of the first distance along the power line, and arrive at the location of the fault point.

It should be noted that it is only necessary to execute the step 102 ahead of the step 104, the acquisition behavior may be, for example, pre-executed, that is, it is ahead of the step 101 or may be executed with the step 101 at the same time, or it is ahead of the step 103 or executed with the step 103 at the same time. The sequence may be determined specifically according to an actual requirement and will not be elaborated herein. Similarly, it is only necessary to execute the step 103 after the fault point occurs on the power line and before the step 104. In addition, the execution sequence of the step 103, the step 104 and the step 101 is not specific, the step 103, the step 104 and the step 101 may be executed at the same time, or the step 103 and the step 104 may be executed before or after the step 101. For example, after a fault of the power line is recognized, a target point and a reference point may be determined first. In this case, a time point set includes time points of arrival of a traveling wave corresponding to the fault point at each determined transformer substation, namely only includes time points of arrival of the traveling wave at the target point and the reference points. Correspondingly, a location set may only include location information about the target point and the reference points. If the target point and the reference points are determined after the time point set is acquired, the situation of taking a transformer substation of which a traveling detection device is faulty as a target point or a reference point can be avoided.

The traveling wave in the present embodiment may be a voltage traveling wave or may be a current traveling wave. The current traveling wave is easier to detect, and lowly requires a locating implementation device, and therefore the cost is relatively low.

According to the present embodiment, after a fault point of a power line is recognized, time of arrival of a traveling wave at a plurality of transformer substations is acquired, an initial target point and a plurality of reference points are determined, the location of the fault point is determined by combining traveling wave time received by a plurality of transformer substations in the same area network, a location set of the plurality of transformer substations and a plurality of reference points, and therefore the location of the fault point can be more accurately determined. Furthermore, the method of the present embodiment does not determine the location of a fault point by means of the wave speed of a traveling wave, thereby avoiding an inaccurate final locating result caused by a possible change of the wave speed.

Embodiment 2

The present embodiment makes a further supplemental description on the method for locating a fault point in an area network based on a traveling wave in the embodiment 1.

FIG. 2 shows a flowchart of a method for locating a fault point in an area network based on a traveling wave according to the present embodiment. The method includes the steps as follows.

Step 201, if a power line has a fault point, a time point set is acquired.

This step is consistent with the step 101, and will not be elaborated herein.

In step 202, a location set is acquired, the location information set including location information about each transformer substation.

It is only necessary to execute the step 202 ahead of step 206, the acquisition behavior may be, for example, pre-executed, that is, it is ahead of the step 201 or may be executed with the step 201 at the same time. The sequence may be determined specifically according to an actual requirement and will not be elaborated herein.

Step 203, a transformer substation is determined from an area network to serve as an initial target point.

For example, one of transformer substations at two ends of the power line where the fault point is located may serve as the initial target point. Specifically, a faulty power line and transformer substations at the two ends of the faulty power line may be determined according to detection or actions of a relay protection device, or which two transformer substations are closest to the fault point may be determined according to received traveling wave time, which will not be elaborated specifically. Because a traveling wave may be attenuated and traveling waves received by the transformer substations at the two ends of the power line, where the fault point is located, are relatively strong, thus detection results of the traveling waves are more accurate, and then final location of the fault point may be relatively accurate.

Step 204, a plurality of transformer substations is determined from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point.

In the present embodiment, all opposite transformer substations of the target point based on the fault point may serve as the reference points. If relay protection devices or traveling wave detection devices of some opposite transformer substations are out of work, such as failing in detecting a traveling wave, all the remaining opposite transformer substations capable of detecting the traveling wave may serve as opposite transformer. For example, as shown in FIG. 3, if the fault point is located between B and D, when B is the target point, the opposite transformer substations of B are D, E, F, G, H, I and J. The power line between the target point and each opposite transformer substations should pass through the fault point. If the fault point is located between D and E, when B is the target point, the opposite transformer substations of B are E, F, G, H, I and J. If the fault point is located between E and G, when E is the target point, the opposite transformer substations of E are G, H, I and J.

In step 205, a time interval between the time of arrival of the traveling wave at the target point and the time of arrival of the travelling wave at each reference point is determined according to the time point set.

The time point set has time points of arrival of the traveling wave at each transformer substation, and more specifically, may have time points of arrival of a wave head of the traveling wave at each transformer substation. Thus, after the target point and the reference points are determined, a time interval between arrival time of the traveling wave at the target point and arrival time of the travelling wave at the each reference point can be determined. The time interval is a positive number.

In step 206, a second distance between the target point and each reference point is determined according to the location set. The step 206 and the step 205 may be executed at the same time, or the step 206 may be executed before or after the step 205, which will not be elaborated specifically.

The second distance is a positive number.

In step 207, a first distance between the fault point and the target point is determined according to each time interval and each second distance.

The first distance is a positive number.

The first distance b/2 between the fault point and the target point may be determined specifically according to a following formula:

From the formula, it can be seen that acquisition of the first distance does not depend on the wave speed of the traveling wave, and is only associated with the locations of reference points, the target point and the time points of arrival of the traveling wave at the transformer substations. Because the wave speed of the traveling wave may be changed due to change of an external environment or may not be accurately measured, the first distance can be acquired more accurately by excluding the wave speed. In addition, the traveling detection device of each transformer substation may not be synchronized in clock, an error of a calculation result caused by a measurement error of the traveling detection device may be reduced by using the above-mentioned formula obtained by fitting a straight line, and therefore the location of the fault point may still be accurately determined.

In step 208, the location of the fault point is determined according to the first distance.

Because the location of the target point and the layout direction of the power line have been known in advance, the location of the fault point can be directly determined after acquiring the fault point and the target point. Staff may directly arrive at the location of the fault point to perform maintenance. Certainly, the staff may also start from the target point, walk for a length of the first distance along the power line, and arrive at the location of the fault point.

Alternatively, between the step 207 and the step 208, the method further includes:

determining another transformer substation from the area network to serve as an updated target point, and returning to execute the step 204 until another first distance between the updated fault point and the updated target point is determined; and

correcting the first distance b/2 between the fault point and the initial target point according to a following formula:

b/2= (a first distance plus a third distance between two transformer substations at two ends of a power line where a fault point is located minus the another first distance) /2.

It is assumed that the initial target point is one of transformer substations at the two ends of the power line where the fault point is located, and the updated target point is the other one of the transformer substations at the two ends of the power line where the fault point is located. Return to execute the step 204 until the another first distance is determined. Correction is performed based on that the acquired another first distance is the first distance corresponding to the initial target point, and the corrected first distance is adopted to execute the step 208.

Because distances with two target points are simultaneously involved in the corrected first distance, a fault point can be more accurately located. Certainly, during actual operation, correction may not be needed, that is, the fault point can be located by using one initial target point, which may be selected specifically according to an actual requirement.

According to the present embodiment, the first distance between the fault point and the target point is determined by means of traveling wave time received by a plurality of transformer substations in the same area network and a location set relevant with the locations of the plurality of transformer substations, then the location of the fault point is determined by means of the first distance, so that the location of the fault point can be determined more accurately.

Embodiment 3

The present embodiment illustrates the method for locating a fault point in an area network based on a traveling wave in the above-mentioned embodiment.

FIG. 3 shows a structure diagram of an area network 300. The area network 300 includes 11 transformer substations namely A, B, C, D, E, G, F, H, I, J and H, every two adjacent transformer substations being connected via a power line. Each transformer substation is provided with a relay protection device or a traveling wave detection device. The relay protection device or the traveling detection device may detect whether a power line is faulty in the area network. When a fault occurs, a traveling wave is emitted from a fault point, wherein the traveling wave can be acquired by the traveling wave detection device. The traveling wave detection device may also acquire a time point of arrival of the traveling wave at the transformer substation. Each traveling wave detection device may communicate with the device for locating the fault point in the area network based on the traveling wave. The device for locating the fault point in the area network based on the traveling wave pre-stores location information about each transformer substation.

It is hypothetically determined that the fault point occurs on the power line between D and E according to the strength of the traveling wave. D is selected as an initial target point, and an distance between the fault point and the target point is d _D, where

d _D= (Δt _DEv+l _DE) /2 (1)

Δt _DE=t _D-t _E (2)

where v represents the wave speed of a traveling wave, l _DE represents a distance between D and E, Δt _DE represents a time interval between time of arrival of a traveling wave at D and at E, t _D represents a time point of arrival of the traveling wave at D, and t _E represents a time point of arrival of the traveling wave at E.

Based on the foregoing formula, when a transformer substation m is selected as a target point and a transformer substation j is selected as a reference point, a distance d _m between the fault point and the target point m may be represented as a following formula:

d _m= (Δt _mjv+l _mj) /2 (3)

Δt _mj=t _m-t _j (4)

where v represents the wave speed of a the traveling wave, l _mj represents an distance between m and j, Δt _mj represents a time interval of arrival of the traveling wave at m and at j, t _m represents a time point of arrival of the a traveling wave at m, and t _j represents a time point of arrival of the a traveling wave at j.

Thus, l _mj=2d _m-Δt _mjv (5)

where the selection number of the target points may be determined to 1, 2, 5 or even more according to an actual requirement, and for example, each transformer substation in the area network may be selected as the target point. When the number of the target points is 1 or 2, not only can the location of the fault point be determined accurately, but also time for determining the location of the faulty point is shorter.

If Y=l _mj, X=Δt _mj, a=-v and b=2d _m, a following straight line fitting formula will be formed according to the formula (5) :

Y=aX+b (6)

After the target point m is determined, n reference points may be selected, so that n items of data will be generated according to the formula (6) .

Correspondingly, a following formula can be generated according to the formula (6) :

where X _i represents a time interval between time of arrival of the traveling wave at the i ^th reference point and time of arrival of the traveling wave at the target point, Y _i represents a second distance between the i ^th reference point and the target point, n represents the number of the reference points, and both i and n are positive integers, a represents a negative of a wave speed of the traveling wave, and b is twice of the first distance between the fault point and the target point.

A following formula is generated according to the formula (7) :

Values of a and b may be acquired according to the formula (8) . From the formula (8) , it can be seen that the value of b does not depend on the value of a, that is, acquisition of location information about the fault point does not depend on the wave speed of the traveling wave. The wave speed of the traveling wave may be changed along with the change of an external environment, the manner of acquiring location information about the fault point in the present embodiment can avoid use of the wave speed of the traveling wave, thereby making a result more accurate.

The following is a specific example in which the fault point occurs between D and E, the traveling wave is a current traveling wave and the wave speed is a speed of arrival of the wave head of the traveling wave at each transformer substation.

Example 1: D is selected as a target point, and in this case, opposite transformer substations of D are E, F, G, H, I, J and H. It is detected that relay protection devices and the traveling wave detection devices of all opposite transformer substations of D are in a normal working state, and therefore all the opposite transformer substations corresponding to D are determined as reference points. Table 1 shows a list of each time point of arrival of the traveling wave at each transformer substation.

Table 1

A time intervals of time of arrival of the traveling wave at each transformer substation are acquired according to Table 1, and a distance between D and opposite transformer substations is determined according to location information pre-acquired by each transformer substation. As shown in Table 2, ΔT represents a time interval between time of arrival of a traveling wave at the reference point and at the target point.

Table 2

Reference point	Distance (km) with target point	ΔT/ (μs)
E	200	133.78
F	280	-133.78
G	320	-267.56

H	670	-1438.13
I	760	-1739.13
J	790	-1839.46

Data in Table 2 is substituted into the formula (8) to obtain a =-0.2990km/μs and b=239.9998km, thereby obtaining the wave speed 2.990×10 ⁵km/s of the traveling wave and a first distance d _D between the fault point and D is 119.9999km.

Thereafter, E may be selected as a target point, and in this case, opposite transformer substations of E are A, B, C and D. It is detected that fault detectors of all opposite transformer substations of E are in a normal working state, and therefore all the opposite transformer substations corresponding to E are determined as reference points. A time interval of arrival of a traveling wave at each transformer substation is acquired according to Table 1, and another first distance between E and opposite transformer substations is determined according to location information pre-acquired by each transformer substation. As shown in Table 3, ΔT represents a time interval of arrival of a traveling wave at each reference point and at the target point.

Table 3

Data in Table 3 is substituted into the formula (8) to finally obtain a=-0.299 km/μs and b=160km, thereby obtaining the wave speed 2.990×10 ⁵km/s of the traveling wave and a first distance d _E 80.00km between the fault point and E.

Thereafter, d _D between the fault point and D is corrected, and a corrected first distance is d _D′.

Because the location of D has been known in advance, a specific geographical location of the fault point can be acquired according to d _D′.

According to practical measurement, the location of the fault point is determined to be 120km away from D.

Example 2

As shown in FIG. 3, it is assumed that traveling wave detection device of E are faulty and fail in detecting a traveling wave. The traveling wave detection devices of F, G and I are not synchronized in clock, thereby causing errors to time points of arrival of the traveling wave, detected by the points F, G and I. A time point of arrival of the traveling wave at each transformer substation is as shown in Table 4.

Table 4

A fault point occurs between D and E, D is a target point, F, G, H, I, J and H are reference points, and relevant data is as shown in Table 5.

Table 5

Data in Table 5 is substituted into the formula (8) to finally obtain a=-0.2973 km/μs and b=238.40km.

That is, a first distance between the fault point and the target point D is d _D=119.20km.

An error is calculated as

e being within an error range of which an error threshold is 5%. That is, the first distance d _D=119.20km is an accurate location.

Because the location of D has been known in advance, a specific geographical location of the fault point can be determined according to d _D.

Embodiment 4

The present embodiment provides a device for locating a fault point in an area network based on a traveling wave, configured to execute the method for locating a fault point in an area network based on a traveling wave in the foregoing embodiment.

FIG. 4 shows a structure diagram of the device for locating the fault point in the area network based on the traveling wave according to the present embodiment. The device for locating the fault point in the area network based on the traveling wave includes: a first acquisition unit 401, a second acquisition unit 402, a first determination unit 403, a second determination unit 404, a third determination unit 405 and a fourth determination unit 406.

The first acquisition unit 401 is configured to acquire a time point set if a power line has a fault point, the time point set including time points of arrival of a traveling wave corresponding to the fault point at each transformer substation; the second acquisition unit 402 is configured to acquire a location set, the location information set including location information about each transformer substation; the first determination unit 403 is configured to determine a transformer substation from the area network to serve as an initial target point; the second determination unit 404 is configured to determine a plurality of transformer substations from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point; the third determination unit 405 is configured to determine a first distance between the fault point and the target point according to the time point set, the location set and the reference points; and the fourth determination unit 406 is configured to determine the location of the fault point according to the first distance.

The first determination unit 403 may be connected to the first acquisition unit 401 to determine one of the transformer substations capable of acquiring a time point of arrival of the traveling wave as the target point. The second determination unit 404 may be connected to the first determination unit 403 to determine the reference points according to the target point determined by the first determination unit 403. Alternatively, the first determination unit 403 may be connected to the third determination unit 405 to directly send information about the target point to the third determination unit 405, or may indirectly send the information to the third determination unit 405 via the second determination unit 404.

The traveling wave may be a current traveling wave. For example, a time point of arrival of the traveling wave at each transformer substation is a time point of arrival of a wave head of the traveling wave at each transformer substation.

A working method of each unit in the present embodiment is the same as that in the foregoing embodiment, and will not be elaborated herein.

According to the present embodiment, after the device for locating the fault point in the area network based on the traveling wave recognizes a fault point of a power line, time of arrival of a traveling wave at a plurality of transformer substations is acquired, an initial target point and a plurality of reference points are determined, the location of the fault point is determined by combining traveling wave time received by the plurality of transformer substations in the same area network, a location set of the plurality of transformer substations and the plurality of reference points, and therefore the location of the fault point can be more accurately determined. Furthermore, the method of the present embodiment does not determine the location of the fault point by means of the wave speed of the traveling wave, thereby avoiding an inaccurate final locating result caused by a possible change of the wave speed.

Embodiment 5

The present embodiment makes a further supplemental description on the device for locating a fault point in an area network based on a traveling wave in the embodiment 4.

Alternatively, as shown in FIG. 5A, the third determination unit 405 in the present embodiment specifically includes a time determination sub-unit 4051, a first distance determination sub-unit 4052 and a second distance determination sub-unit 4053.

The time determination sub-unit 4051 is configured to determine a time interval between time of arrival of the traveling wave at the target point and at each reference point according to the time point set; the first distance determination sub-unit 4052 is configured to determine a second distance between the target point and each reference point according to the location set; and the second distance determination sub-unit 4053 is configured to determine a first distance between the fault point and the target point according to each time interval and each second distance.

The second determination unit 404 is specifically configured to: determine transformer substations (the power line between the transformer substations and the target point needs to pass through the fault point) from the remaining transformer substations to serve as reference points.

The first determination unit 403 is specifically configured to: determine one of transformer substations at two ends of the power line where the fault point is located to serve as the initial target point.

Alternatively, the second distance determination sub-unit is specifically configured to:

Alternatively, as shown in FIG. 5B, the device for locating the fault point in the area network based on the traveling wave in the present embodiment further includes a correction unit 501, the correction unit 501 being configured to determine another transformer substation from the area network to serve as an updated target point, and return to trigger the second determination unit 404 until another first distance between the fault point and the updated target point is determined; and

correct a first distance b/2between the fault point and the initial target point according to a following formula:

b/2= (a first distance plus a third distance between two transformer substations at two ends of a power line where the fault point is located minus the another first distance) /2.

The initial target point may be one of the transformer substations at the two ends of the power line where the fault point is located, and the updated target point may be the other one of the transformer substations at the two ends of the power line where the fault point is located.

According to the present embodiment, a first distance between a fault point and a target point is determined by means of traveling wave time received by a plurality of transformer substations in the same area network and a location set of the plurality of transformer substations, and then the location of the fault point is determined by means of the first distance, so that the location of the fault point can be determined more accurately.

Embodiment 6

The present embodiment provides another device for locating a fault point in an area network based on a traveling wave, the area network including a plurality of transformer substations, and every two adjacent transformer substations being connected via a power line. As shown in FIG. 6, a device 600 for locating a fault point in an area network based on a traveling wave includes at least one communication interface 601, at least one memory 602 and at least one processor 603.

The communication interface 601 is configured to communicate with each transformer substation; the memory 602 is configured to store location information about each transformer substation; and the processor 603 is connected to the communication interface 601 and the memory 602, and is configured to acquire data sent by the communication interface 601 and the location information in the memory 602, the processor 603 being configured to execute the method for locating a fault point in an area network based on a traveling wave in the foregoing embodiment. The memory 602 may be disposed in the processor 603, or may be disposed independently.

For example, there may be two communication interfaces 601, one of which may communicate with a traveling wave detection device to receive a time point of arrival of a traveling wave corresponding to a fault point at each transformer substation, and the other one may communicate with the relay protection device. The location information in the memory 602 may be pre-stored. The processor 603 may execute the method for locating a fault point in an area network based on a traveling wave in any one of the foregoing embodiments.

According to the present embodiment, after the device for locating the fault point in the area network based on the traveling wave recognizes the fault point of a power line, time of arrival of the traveling wave at a plurality of transformer substations is acquired, an initial target point is determined, the location of the fault point is determined by combining traveling wave time received by the plurality of transformer substations in the same area network and a location set of the plurality of transformer substations, and therefore the location of the fault point can be more accurately determined. Furthermore, the method of the present embodiment does not determine the location of a fault point by means of a wave speed of the traveling wave, thereby avoiding a possibility of an inaccurate final locating result caused by a possible change of the wave speed.

The present invention also provides a device for locating a fault point in an area network based on a traveling wave, including at least one memory and at least one processor. The memory is configured to store an instruction. The processor is configured to execute, by means of the instruction stored by the memory, the method for locating a fault point in an area network based on a traveling wave described in any one of the foregoing embodiments.

The embodiment of the present invention also provides a readable storage medium. A machine-readable instruction is stored in the readable storage medium, and when the machine-readable instruction is executed by a machine, the machine executes the method for locating a fault point in an area network based on a traveling wave described in any one of the foregoing embodiments.

The readable medium stores a machine-readable instruction, and when the machine-readable instruction is executed by a processor, the processor executes any one of the foregoing methods. Specifically, a system or device equipped with a readable storage medium may be provided, software program codes implementing functions of any one of the above-mentioned embodiments are stored on the readable storage medium, and a computer or processor of the system or device reads and executes a machine-readable instruction stored in the readable storage medium.

Under this circumstance, the program codes read from the readable medium per se may implement functions of any one of the above-mentioned embodiments, and therefore machine-readable codes and a readable storage medium storing the machine-readable codes constitute a part of the present invention.

Embodiments of the readable storage medium include a floppy disk, a hard disk, a magnetic disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW and DVD+RW) , a magnetic tape, a non-volatile memory card and an ROM. Alternatively, program codes may be downloaded from a server computer or a cloud via a communication network.

It should be noted that not all steps and units in each flow and each system structure diagram above are necessary, and some steps or units may be omitted according to an actual requirement. The execution sequence of all steps is not fixed, and may be adjusted as required. The device structure described in each of the above-mentioned embodiments may be a physical structure, or may be a logic structure. That is, some units may be implemented by the same physical entity, or some units may be implemented by a plurality of physical entities or may be implemented jointly by some components in a plurality of pieces of independent equipment.

In each of the above-mentioned embodiments, a hardware unit may be implemented by means of a mechanical manner or electrical manner. For example, a hardware unit or processor may include a permanent dedicated circuit or logic (such as a dedicated processor, FPGA or ASIC) for completing corresponding operations. The hardware unit or processor may further include a programmable logic or circuit (such as universal processors or other programmable processors) , which may be temporarily set by software to complete corresponding operations. A specific implementation manner (mechanical manner, or dedicated permanent circuit, or temporarily set circuit) may be determined in view of cost and time.

The present invention was displayed and illustrated with the drawings and the preferred embodiments above in detail. However, the present invention is not limited to these disclosed embodiments. Based on the plurality of above-mentioned embodiments, those skilled in the art may know that more embodiments of the present invention may be obtained by combining code checking means in different embodiments, these embodiments also falling within the scope of protection of the present invention.

The above is only the preferred embodiments of the present invention, and is not used to limit the present invention. Any modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present invention should fall within the scope of protection of the present invention.

Claims

A method for locating a fault point in an area network based on a traveling wave, the area network comprising a plurality of transformer substations, every two adjacent transformer substations being connected via a power line, and the method being characterized by comprising:

if a power line has a fault point , acquiring a time point set, the time point set comprising time points of arrival of a traveling wave corresponding to the fault point at each transformer substation;

acquiring a location set, the location information set comprising location information about each transformer substation;

determining a transformer substation from the area network to serve as an initial target point;

determining a plurality of transformer substations from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point;

determining a first distance between the fault point and the target point according to the time point set, the location set and the reference points; and

determining a location of the fault point according to the first distance.
The method according to claim 1, characterized in that determining the first distance between the fault point and the target point according to the time point set, the location set and the reference points comprises:

determining a time interval between time of arrival of the traveling wave at the target point and at each reference point according to the time point set;

determining a second distance between the target point and each reference point according to the location set; and

determining the first distance between the fault point and the target point according to each time interval and each second distance.
The method according to claim 2, characterized in that determining the transformer substation from the area network to serve as the initial target point comprises:

determining one of transformer substations at two ends of the power line where the fault point is located to serve as an initial target point.
The method according to claim 2, characterized in that after determining the first distance between the fault point and the target point according to each time interval and each second distance, and before determining the location of the fault point according to the first distance, the method further comprises:

determining another transformer substation from the area network to serve as an updated target point, and returning to the operation of determining the plurality of reference points from the remaining transformer substations until another first distance between the fault point and the updated target point is determined; and

correcting a first distance b/2 between the fault point and the initial target point according to a following formula:

b/2= (the first distance plus a third distance between two transformer substations at two ends of a power line where the fault point is located minus the another first distance) /2.
The method according to claim 4, characterized in that the initial target point is one of transformer substations at two ends of the power line where the fault point is located, and the updated target point is the other one of the transformer substations at the two ends of the power line where the fault point is located.
The method according to any one of claims 2 to 5, characterized in that determining the first distance between the fault point and the target point according to each time interval and each second distance comprises:

determining the first distance b/2 between the fault point and the target point according to a following formula:

where X _i represents a time interval between time of arrival of the traveling wave at the i ^th reference point and time of arrival of the traveling wave at the target point, Y _i represents a second distance between the i ^th reference point and the target point, n represents the number of the reference points, both i and n are positive integers, a represents a negative of a wave speed of the traveling wave, and b is twice of the first distance between the fault point and the target point.
The method according to any one of claims 1 to 5, characterized in that the traveling wave is a current traveling wave.
The method according to any one of claims 1 to 5, characterized in that a time point of arrival of the traveling wave at each transformer substation is a time point of arrival of a wave head of the traveling wave at each transformer substation.
A device for locating a fault point in an area network based on a traveling wave, the area network comprising a plurality of transformer substations, every two adjacent transformer substations being connected via a power line, and the device being characterized by comprising:

a first acquisition unit, configured to acquire a time point set if a power line has a fault point, the time point set comprising time points of arrival of a traveling wave corresponding to the fault point at each transformer substation;

a second acquisition unit, configured to acquire a location set, the location information set comprising location information about each transformer substation;

a first determination unit, configured to determine a transformer substation from the area network to serve as an initial target point;

a second determination unit, configured to determine a plurality of transformer substations from the remaining transformer substations to serve as reference points corresponding to the target point, wherein the power line between at least two reference points and the target point needs to pass through the fault point;

a third determination unit, configured to determine a first distance between the fault point and the target point according to the time point set, the location set and the reference points; and

a fourth determination unit, configured to determine a location of the fault point according to the first distance.
The device according to claim 9, characterized in that the third determination unit specifically comprises:

a time determination sub-unit, configured to determine a time interval between time of arrival of the traveling wave at the target point and at each reference point according to the time point set;

a first distance determination sub-unit, configured to determine a second distance between the target point and each reference point according to the location set; and

a second distance determination sub-unit, configured to determine the first distance between the fault point and the target point according to each time interval and each second distance.
The device according to claim 10, characterized in that the first determination unit is specifically configured to:

determine one of transformer substations at two ends of the power line where the fault point is located to serve as an initial target point.
The device according to claim 10, characterized by further comprising a correction unit, configured to:

determine another transformer substation from the area network to serve as an updated target point, and return to trigger the second determination unit until another first distance between the fault point and the updated target point is determined; and

correct a first distance b/2 between the fault point and the initial target point according to a following formula:

b/2 = (the first distance plus a third distance between two transformer substations at two ends of the power line where the fault point is located minus the another first distance) /2.
The device according to claim 12, characterized in that the initial target point is one of transformer substations at the two ends of the power line where the fault point is located, and the updated target point is the other one of the transformer substations at the two ends of the power line where the fault point is located.
The device according to any one of claims 10 to 13, characterized in that the second distance determination sub-unit is specifically configured to:

determine the first distance b/2 between the fault point and the target point according to a following formula:

where X _i represents a time interval between time of arrival of the traveling wave at the i ^th reference point and time of arrival of the traveling wave at the target point, Y _i represents the second distance between the i ^th reference point and the target point, n represents the number of the reference points, both i and n are positive integers, a represents a negative of a wave speed of the traveling wave, and b is twice of the first distance between the fault point and the target point.
The device according to any one of claims 9 to 13, characterized in that the traveling wave is a current traveling wave.
The device according to any one of claims 9 to 13, characterized in that a time point of arrival of the traveling wave at each transformer substation is a time point of arrival of a wave head of the traveling wave at each transformer substation.
A device for locating a fault point in an area network based on a traveling wave, the area network comprising a plurality of transformer substations, every two adjacent transformer substations being connected via a power line, and the device being characterized by comprising:

at least one communication interface, configured to communicate with each transformer substation;

at least one memory, configured to store location information about each transformer substation; and

at least one processor, connected to the communication interface and the memory, and acquiring data sent by the communication interface and the location information in the memory, and the processor being configured to execute the method for locating a fault point in an area network based on a traveling wave according to any one of claims 1 to 8.
A device for locating a fault point in an area network based on a traveling wave, the area network comprising a plurality of transformer substations, every two adjacent transformer substations being connected via a power line, and the device being characterized by comprising:

at least one memory, configured to store an instruction; and

at least one processor, configured to execute, by means of the instruction stored by the memory, the method for locating a fault point in an area network based on a traveling wave according to any one of claims 1 to 8.
A readable storage medium, characterized in that a machine-readable instruction is stored in the readable storage medium, and when the machine-readable instruction is executed by a machine, the machine executes the method for locating a fault point in an area network based on a traveling wave according to any one of claims 1 to 8.