Distribution network fault positioning method independent of branch line equipment

Abstract

The invention relates to a distribution network fault positioning method independent of branch line equipment, and the method comprises the steps: determining a topological structure of a distribution line, and configuring a traveling wave monitoring terminal according to the line condition; the method comprises the following steps: extracting phase-mode traveling waves collected by all traveling wave monitoring terminals when a line fails, decomposing the phase-mode traveling waves into zero-mode traveling waves and line-mode traveling waves, and then respectively calculating wave head time differences; selecting a line as a main line, and respectively calculating the distance between the fault point and the traveling wave monitoring terminals at the head and tail of the selected main line; if the corresponding condition is met, that is, the fault point is located on the main line, determining the specific position of the fault point on the main line; if the corresponding condition is not met, the fault point is located on a certain branch line, and the next step is executed; determining the distance between the fault point and the T contact of the branch line; and determining the distance from the fault point to the main line upgoing wave monitoring terminal. The method has the advantages that under the condition that multiple branches exist in a distribution network line and equipment on the branch lines is lacked, judgment of the main line and the branch lines of the fault points and judgment of the accurate positions of the fault points can still be achieved.

Description

Technical Field

[0001] The present invention relates to the field of distribution network fault location, and in particular to a distribution network fault location method that does not rely on branch line equipment. Background Art

[0002] As the last link of power transmission, the distribution network is directly responsible for the supply of electricity to users, and its power supply reliability is closely related to the development of the national economy. With the continuous adjustment of the energy structure and the rapid economic development, the new era has higher requirements for power supply reliability. However, the current distribution network is in complex and severe external conditions. Affected by weather, disasters and human factors, failures are inevitable. How to accurately locate the fault point, quickly troubleshoot the fault, and improve the reliability of the system power supply is a long-standing problem in the distribution network.

[0003] Distribution networks generally contain many branches, which makes it more difficult to locate distribution networks than transmission networks. In addition, in a neutral point non-effectively grounded system, the fault current is weak and the arc is unstable, which makes fault location more difficult. Traditional fault location methods have many problems. The following are several traditional fault location methods:

[0004] 2.1 Trial pull method

[0005] The faulty line is determined by testing the power supply, and then the operating personnel determine the location of the fault point along the line with the naked eye. This method not only consumes a lot of manpower and material resources, but also easily causes phase-to-phase short circuit deterioration during the test power supply process. In addition, the environment in places with complex terrain such as mountain villages and rivers is harsh and the fault troubleshooting time is long, making this method inefficient and economically uneconomical, and unable to adapt to distribution network automation.

[0006] 2.2 Relay protection within the station

[0007] The in-station relay protection can monitor the current changes, voltage changes, and frequency changes of the line, and determine whether the line has a fault (three-phase short circuit, two-phase short circuit, single-phase grounding, etc.) and an abnormal operating state (overload, overvoltage, low voltage, etc.) according to the pre-set setting values. It can quickly and selectively issue a tripping command to cut off the fault or issue an alarm, thereby reducing the scope of power outages and the degree of damage to electrical equipment caused by the fault, and ensuring the stable operation of the power system. However, it cannot determine the interval where the hybrid line fault occurs, let alone accurately locate the fault.

[0008] 2.3 Impedance ranging method

[0009] The impedance ranging method is also known as the generalized fault analysis method. The ranging device calculates the impedance of the fault circuit based on the voltage and current measured when the overhead transmission line fails. Since the line length is proportional to the impedance, the distance from the device installation to the fault point can be calculated based on the calculated impedance and the reference impedance of the line. Specifically: the ranging device first calculates based on the collected electrical quantities to determine the fault type, and then enters the corresponding fault type calculation program to calculate the fault circuit impedance. However, in the field of hybrid line fault location, the ranging accuracy is limited and the reliability of interval positioning is poor due to the influence of line characteristics, fault point grounding resistance, etc.

[0010] 2.4 Power frequency method

[0011] The power frequency method arranges power frequency current and voltage measuring devices on the mixed rack nodes and busbars to monitor the power frequency characteristics at each node. When a hybrid line fault occurs, the fault interval is determined based on the overcurrent situation and the polarity and direction of the power frequency current. The investment cost is relatively low, but it can only determine the fault interval and cannot accurately locate the fault.

[0012] 2.5 Distributed Traveling Wave Ranging Method

[0013] When a hybrid line fails, current and voltage traveling waves will be generated at the fault point and transmitted to both ends of the line. The distributed traveling wave ranging method extracts the fault traveling wave by arranging traveling wave monitoring terminals at all mixed points, and uses the difference in traveling wave polarity extracted between the two monitoring terminals to realize fault interval discrimination, and uses wavelet transform and other methods to extract the traveling wave head, and calculates the time difference between the two traveling wave heads to realize accurate fault location. Although the distributed traveling wave ranging technology can solve the problem of mixed line fault location very well, there are many branches in the distribution line. The traveling wave method faces many new difficulties in locating distribution network faults. The most concentrated problem is that the transmission line generally does not contain T-connection or only contains one T-connection. Generally, two or three sets of equipment can realize the fault location of the entire line. However, for the distribution network line, due to the existence of many branch lines, if the branch line needs to be accurately located, a set of fault monitoring terminals must be installed at the end of each branch line. Due to the investment cost problem, the traveling wave method is difficult to be widely popularized and applied in distribution lines. Summary of the invention

[0014] The technical problem to be solved by the present invention is to provide a distribution network fault locating method that does not rely on branch line equipment, so as to overcome the deficiencies in the above-mentioned prior art.

[0015] The technical solution of the present invention to solve the above technical problem is as follows: A distribution network fault location method that does not rely on branch line equipment includes the following steps:

[0016] S100, determining the topological structure of the power distribution line and configuring the traveling wave monitoring terminal according to the line conditions;

[0017] S200, when a line fault occurs, extract the phase mode traveling waves collected by all traveling wave monitoring terminals, decompose them into zero mode traveling waves and line mode traveling waves, and then calculate the time difference between the zero mode traveling wave head and the line mode traveling wave head collected by each traveling wave monitoring terminal;

[0018] S300, select a line as the main line, and calculate the distance l between the fault point F and the first and last traveling wave monitoring terminals of the selected main line MF and l NF ;

[0019] S400, if l is satisfied MF +l NF = l MN , that is, the fault point F is located on the main line, and then according to l MF or NF The specific location of the fault point F on the main line can be determined; if l MF +l NF > MN , then the fault point F is located on a branch line and enters S500;

[0020] S500: Determine the distance between the fault point F and the T junction of the branch line where it is located

[0021] S600: Determine the distance between the fault point F and the main line up-wave monitoring terminal M according to The length can determine the exact location of the branch line where the fault point is located.

[0022] Based on the above technical solution, the present invention can also be improved as follows.

[0023] Furthermore, the configuration principles of the traveling wave monitoring terminal in S100 are as follows:

[0024] If there are no other branch lines on the T-connection of the line, a traveling wave monitoring terminal is configured at the beginning and end of the line;

[0025] If the T-connection of the line contains a single branch, a traveling wave monitoring terminal shall be configured at the beginning and end of the line and at the end of the T-connection;

[0026] If the T-connection of the line contains multiple branches, a traveling wave monitoring terminal is configured at the beginning and end of the line and at the end of the single branch line under multiple branches;

[0027] If the T-connection of the line contains multiple single branches, traveling wave monitoring terminals are configured at the beginning and end of the line and at the end of the T-connection.

[0028] Furthermore, in S300 MF and l NF The calculation formulas are:

[0029]

[0030]

[0031] Among them, △t M is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at M, △t N is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at N, v1 is the line-mode traveling wave velocity, and v0 is the zero-mode traveling wave velocity.

[0032] Furthermore, in S500 The calculation formula is:

[0033]

[0034] Furthermore, in S600 The calculation formula is:

[0035]

[0036] Furthermore, the traveling wave monitoring terminal has a power supply module, a traveling wave voltage sensor, a traveling wave current sensor, a GPS / Beidou synchronization clock, a communication unit and a collection unit. The traveling wave voltage sensor and the traveling wave current sensor respectively collect the line fault power frequency voltage and current and traveling wave current signals in real time, and transmit the collected signals to the remote central station through the communication unit.

[0037] The beneficial effects of the present invention are:

[0038] Based on the time difference between the wave heads of the zero-mode traveling wave and the line-mode traveling wave collected by the traveling wave monitoring terminal on one side, the distance between the fault point and the traveling wave monitoring terminal on that side can be calculated. Similarly, the traveling wave monitoring terminal on the opposite side can also obtain the distance between the fault point and the traveling wave monitoring terminal on the opposite side based on the time difference. Then, the precise location of the fault point can be determined by the two distances and the total length of the line. This method can still determine the location of the fault point on the main line and the branch line, as well as the exact location of the fault point, when there are multiple branches in the distribution network and there is a lack of equipment on the branch line. This provides a new idea for the large-scale application of the traveling wave method in the distribution network, and can greatly reduce the number of traveling wave monitoring terminals used, effectively reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of the distribution network fault location method that does not rely on branch line equipment in the present invention;

[0040] Figure 2 It is the relationship between the wave velocity and frequency of zero mode traveling wave and line mode traveling wave;

[0041] Figure 3 This is a single branch distribution network line fault diagram;

[0042] Figure 4 This is a schematic diagram of a typical complex distribution network structure;

[0043] Figure 5 This is a fault diagram when the main line contains multiple single branches and the fault occurs on a branch line;

[0044] Figure 6 This is the fault diagram when the main line contains multiple single branches and the fault occurs on the main line. DETAILED DESCRIPTION

[0045] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0046] Example 1

[0047] like Figure 1 As shown, a distribution network fault location method that does not rely on branch line equipment includes the following steps:

[0048] S100, determining the topological structure of the power distribution line and configuring the traveling wave monitoring terminal according to the line conditions;

[0049] S200, when a line fault occurs, extract the phase mode traveling waves collected by all traveling wave monitoring terminals, decompose them into zero mode traveling waves and line mode traveling waves, and then calculate the time difference between the zero mode traveling wave head and the line mode traveling wave head collected by each traveling wave monitoring terminal;

[0050] S300, select a line as the main line, and calculate the distance l between the fault point F and the first and last traveling wave monitoring terminals of the selected main line MF and l NF ;

[0051] S400, if l is satisfied MF +l NF = l MN , that is, the fault point F is located on the main line, and then according to l MF or NF The specific location of the fault point F on the main line can be determined; if l MF +l NF > MN , then the fault point F is located on a branch line and enters S500;

[0052] S500: Determine the distance between the fault point F and the T junction of the branch line where it is located

[0053] S600: Determine the distance between the fault point F and the main line up-wave monitoring terminal M according to The length can determine the exact location of the branch line where the fault point is located.

[0054] Example 2

[0055] This embodiment is a further optimization based on Embodiment 1, and its details are as follows:

[0056] The configuration principles of the traveling wave monitoring terminal in S100 are as follows:

[0057] If there are no other branch lines on the T-connection of the line, a traveling wave monitoring terminal is configured at the beginning and end of the line;

[0058] If the T-connection of the line contains a single branch, a traveling wave monitoring terminal shall be configured at the beginning and end of the line and at the end of the T-connection;

[0059] If the T-connection of the line contains multiple branches, a traveling wave monitoring terminal is configured at the beginning and end of the line and at the end of the single branch line under multiple branches;

[0060] If the T-connection of the line contains multiple single branches, traveling wave monitoring terminals are configured at the beginning and end of the line and at the end of the T-connection.

[0061] like Figure 4 As shown in the figure, it is a schematic diagram of a typical complex distribution network topology structure, which includes four typical branch line situations, namely: there are no other branch lines on the T-connection of the line, the T-connection of the line contains a single branch, the T-connection of the line contains multiple branches, and the T-connection of the line contains multiple single branches.

[0062] Example 3

[0063] This embodiment is a further optimization based on Embodiment 1 or 2, and its details are as follows:

[0064] S300 MF and l NF The calculation formulas are:

[0065]

[0066]

[0067] Among them, △t M is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at M, △t N is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at N, v1 is the line-mode traveling wave velocity, and v0 is the zero-mode traveling wave velocity.

[0068] Going further:

[0069] S500 The calculation formula is:

[0070]

[0071] S600 The calculation formula is:

[0072]

[0073] Example 4

[0074] This embodiment is a further optimization based on Embodiment 1, 2 or 3, and its details are as follows:

[0075] The traveling wave monitoring terminal has a power supply module, a traveling wave voltage sensor, a traveling wave current sensor, a GPS / Beidou synchronous clock, a communication unit and a collection unit. The traveling wave voltage sensor and the traveling wave current sensor respectively collect the line fault power frequency voltage and current and traveling wave current signals in real time, and transmit the collected signals to the remote central station through the communication unit. The collection unit can use a 4G collection unit or a 5G collection unit.

[0076] Application Examples

[0077] When a distribution network line fails, a transient traveling wave current i is transmitted from the fault point F to both ends of the line. a 、i b 、i c , the traveling wave current will be zero mode i0, line mode i α 、i β The transmission mode is transmitted to both ends. The relationship between the modulus traveling wave and the phasor traveling wave can be obtained by Karen Boolean transformation, that is, how to obtain the zero-sequence current from the phase current, and the subsequent zero-sequence and positive-sequence current wave speed and frequency relationship is theoretically derived. The specific formula is as follows:

[0078]

[0079] Among them: the transmission loop of the zero-mode traveling wave is the earth, and the zero-mode wave speed is greatly affected by factors such as the frequency of the traveling wave. The higher the frequency of the zero-mode traveling wave, the faster the wave speed. When the line-mode traveling wave is transmitted on the transmission line, the line-mode wave speed basically does not change with the frequency and is very close to the speed of light c.

[0080] The attenuation constant of the zero-mode traveling wave is:

[0081]

[0082] The zero-mode wave velocity can be calculated from the above formula:

[0083]

[0084] From the above formula, we can see that as the frequency increases, the zero-mode wave velocity increases, while for line-mode traveling waves, the frequency change basically does not affect the magnitude of the positive-sequence resistance and the positive-sequence inductance. Therefore, the frequency basically does not affect the line-mode traveling wave velocity. The time difference between the zero-mode and line-mode wave velocities is as follows: Figure 2As shown in the figure, the general frequency range of traveling waves is mostly concentrated in the range of 10kHz to 1MHz. In this range, the zero-mode traveling wave velocity is 2.51×10 8 m / s increases to 2.89×10 8 m / s, the zero-mode traveling wave increases by 15.1%, while the line-mode traveling wave has a velocity of 2.98×10 8 m / s increases to 3.00×10 8 m / s, the wave speed only increased by 0.7%.

[0085] Since there is a difference in the transmission speed of zero-mode traveling wave and line-mode traveling wave, there will be a time difference in the wave head time when the zero-mode traveling wave and the line-mode traveling wave are transmitted to the traveling wave monitoring terminal. The distance to the fault point can be calculated using this time difference, which is:

[0086]

[0087] Wherein, l1 is the distance from the fault point to the measurement point, v1 is the line mode traveling wave velocity, v0 is the zero mode traveling wave velocity, t1 is the line mode traveling wave head time, and t0 is the zero mode traveling wave head time.

[0088] Since there is a time difference between the zero-mode traveling wave head and the line-mode traveling wave head, the distance between the fault point and the traveling wave monitoring terminal can be calculated based on the time difference between the two traveling waves arriving at the traveling wave monitoring terminal.

[0089] like Figure 3 The figure shows a single-branch distribution network line, where F1 is the fault point on the branch line, and F2 is the fault point on the main line. Traveling wave monitoring terminals are arranged at the M and N measuring points at the beginning and end of the main line respectively. If only the traveling wave monitoring at point M is used to determine the fault location, it is impossible to determine whether the fault point is on the branch line or on the main line.

[0090] In view of the above problems, a fault location solution for distribution network lines with T-connected lines is proposed. Assuming that the fault occurs at the main line F2, the traveling wave monitoring terminals at the measuring points M and N can collect the zero-mode traveling wave head and the line-mode traveling wave head respectively. Then, the distance from the fault point F2 to the traveling wave monitoring terminals at M and N is calculated based on the time difference. The specific formula is:

[0091]

[0092]

[0093] Among them, the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at M is △t N is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at N, v1 is the line-mode traveling wave velocity, v0 is the zero-mode traveling wave velocity, l MFis the distance between the fault point F and point M, l NF is the distance between the fault point F and point N.

[0094] When the fault point occurs on the main line, the two l MF and l NF The total length of the line can be formed, namely:

[0095] l MN = l MF +l NF

[0096] However, if the fault occurs at the location of the line branch F1, the sum of the distance from the fault point F to point M and the distance from point N cannot constitute the total length of the main line, that is:

[0097] l MF +l NF =(l MT +l TF )+(l NT +l TF )

[0098] = l MN +2l TF

[0099] Generally, the total length of the line and the location of the T-point are the basic information of the line, from which the distance between the fault point and the T-point can be obtained:

[0100]

[0101] From the above analysis, the fault location criterion for the distribution network with single T connection can be obtained:

[0102] If the conditions are met: MN = l MF +l NF , then the fault point is on the main line, and the distance between the fault point and point M is l MF ;

[0103] If the conditions are met: MF +l NF >l MN , then the fault point is located on the branch line, and the distance between the fault point and the T junction is l TF .

[0104] The above analysis shows how to determine whether the fault point is located on the branch line and the method of fault location in the single-branch distribution network line. However, in actual distribution network lines, there are often many branch lines in the line, and the line branches also contain secondary branches. Therefore, the corresponding solutions are given for fault location under complex multi-branch distribution network structures in the future.

[0105] Step 1: Configure the traveling wave monitoring terminal

[0106] First, the distribution network line topology needs to be drawn according to the line structure and connection relationship, and then the traveling wave monitoring terminal is configured according to the line structure. The traveling wave monitoring terminal can collect the line fault power frequency voltage and current, and traveling wave current signals in real time, and transmit the collected signals to the remote central station through the communication unit. The central station implements unified analysis and processing to decompose the phase-mode traveling wave into zero-mode traveling wave and line-mode traveling wave, extract the zero-mode traveling wave head time and line-mode traveling wave head time respectively, and calculate the time difference.

[0107] like Figure 4 The figure shows a typical complex distribution network topology diagram, where A, B, C...K are line monitoring terminals, T1, T2...T9 are line T-connections. In order to minimize the cost of line traveling wave monitoring devices and accurately determine whether the fault point is located in the branch line or the main line, different configuration principles need to be formulated according to the line conditions:

[0108] 1) There is no branch T connection on the T connection. As shown in the figure, there is no other branch line on T1B. If you need to locate the fault on branch line T1B, you only need to install the traveling wave monitoring terminal at points A and K;

[0109] 2) The T connection contains a single branch, as shown in T2D in the figure. Branch line T2D contains a single branch line T5C. In order to determine whether the fault is on T2D or branch line T5C, AD needs to be regarded as the main line of the line and the problem is converted into a single T connection line fault location problem. At this time, another set of traveling wave monitoring terminal needs to be installed at D;

[0110] 3) The T connection contains multiple branches, such as T3E in the figure. Branch line T3E also contains branch line T6G, and branch line T6G also contains branch line T7F. In this case of multiple branch lines, taking AE as the main line, it can be determined whether the fault point is in the AE section or in the T6G section. Furthermore, taking EG as the main line, it can be determined that the fault point is located on the EG line or on the branch line T7F. Therefore, traveling wave monitoring terminals need to be installed on both E and G.

[0111] 4) The T connection contains multiple single branches, such as T4I in the figure. There are branch lines T8J and T9H on branch line T4I. Taking AI as the main line, it can be determined that the fault point is located at T9H, T8J or on the main line AI. In this case, a traveling wave monitoring terminal needs to be added at I.

[0112] Figure 4 The four branches on the central main line are typical branches in distribution network lines. All complex structure distribution network lines can be configured according to the above principles.

[0113] Step 2: Calculate the single-ended distance

[0114] Since the principles of locating and judging the fault location are the same, such as Figure 5 , Figure 6 As shown in the figure, the subsequent discussion of multi-branch fault location takes the main line containing multiple single branches as an example for analysis. As shown in the figure, it is a simplified schematic diagram of the multi-branch power grid structure. Only the traveling wave monitoring terminal is installed at the M and N positions at the beginning and end of the line. There are n T connections on the line, and the T contacts are numbered T1, T2, T3...T n .

[0115] From the above conclusions, it can be seen that the distance between the fault point and the traveling wave monitoring terminal is:

[0116]

[0117]

[0118] Step 3: Determine the fault branch line and fault location

[0119] Combined with the conclusion of the single branch fault analysis above, if the following conditions are met: MN = l MF +l NF , then the fault point is on the main line, and the distance between the fault point and point M is l MF ;

[0120] If the conditions are met: MF +l NF >l MN , then the fault point is located on a branch line, and the shortest paths of the zero-mode traveling wave and line-mode traveling wave generated by the fault point to reach point M and point N can be expressed as:

[0121]

[0122]

[0123] From this, the distance between the T-junction where the fault point is located and the fault point can be calculated:

[0124]

[0125] There are many T-connections in the line, and it is necessary to determine the specific T-connection position of the fault point. The total length of the line and the position of each T-connection point are the default known basic information of the line. Therefore, the distance between the fault T-connection and the main line can be obtained as:

[0126]

[0127] according to The length can determine the exact location of the branch line where the fault point is located.

[0128] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A distribution network fault location method that does not rely on branch line equipment, characterized in that: The steps include: S100, determining the topological structure of the power distribution line and configuring the traveling wave monitoring terminal according to the line conditions; S200, when a line fault occurs, extract the phase mode traveling waves collected by all traveling wave monitoring terminals, decompose them into zero mode traveling waves and line mode traveling waves, and then calculate the time difference between the zero mode traveling wave head and the line mode traveling wave head collected by each traveling wave monitoring terminal; S300, select a line as the main line, and calculate the distance l between the fault point F and the first and last traveling wave monitoring terminals of the selected main line MF and l NF ; S400, if l is satisfied MF +l NF = l MN , that is, the fault point F is located on the main line, and then according to l MF or NF The specific location of the fault point F on the main line can be determined; if l MF +l NF > MN , then the fault point F is located on a branch line and enters S500; S500: Determine the distance between the fault point F and the T junction of the branch line where it is located S600: Determine the distance between the fault point F and the main line up-wave monitoring terminal M according to The length can determine the exact location of the branch line where the fault point is located.

2. According to claim 1, a distribution network fault location method that does not rely on branch line equipment is characterized in that: The configuration principles of the traveling wave monitoring terminal in S100 are as follows: If there are no other branch lines on the T-connection of the line, a traveling wave monitoring terminal is configured at the beginning and end of the line; If the T-connection of the line contains a single branch, a traveling wave monitoring terminal shall be configured at the beginning and end of the line and at the end of the T-connection; If the T-connection of the line contains multiple branches, a traveling wave monitoring terminal is configured at the beginning and end of the line and at the end of the single branch line under multiple branches; If the T-connection of the line contains multiple single branches, traveling wave monitoring terminals are configured at the beginning and end of the line and at the end of the T-connection.

3. A distribution network fault location method that does not rely on branch line equipment according to claim 1 or 2, characterized in that: S300 MF and l NF The calculation formulas are: Among them, △t M is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at M, △t N is the time difference between the zero-mode traveling wave head and the line-mode traveling wave head collected by the traveling wave monitoring terminal at N, v1 is the line-mode traveling wave velocity, and v0 is the zero-mode traveling wave velocity.

4. A distribution network fault location method that does not rely on branch line equipment according to claim 1, 2 or 3, characterized in that: S500 The calculation formula is:

5. A distribution network fault location method that does not rely on branch line equipment according to claim 4, characterized in that: S600 The calculation formula is:

6. A distribution network fault location method that does not rely on branch line equipment according to any one of claims 1 to 5, characterized in that: The traveling wave monitoring terminal has a power supply module, a traveling wave voltage sensor, a traveling wave current sensor, a GPS / Beidou synchronous clock, a communication unit and a collection unit. The traveling wave voltage sensor and the traveling wave current sensor respectively collect the line fault power frequency voltage and current and traveling wave current signals in real time, and transmit the collected signals to the remote central station through the communication unit.

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