A single - end fault location method and device for transmission line fault points based on the traveling - wave method

Abstract

The present invention discloses a single - end fault location method and device for a transmission line based on the traveling - wave method. The method includes the steps of: determining and marking on a waveform diagram the waveform mutation point T0 corresponding to the time when the traveling wave first reaches the monitoring device; selecting a waveform mutation point near T0 on the waveform diagram as a reference point; calculating and marking on the waveform diagram multiple other characteristic points based on the selected reference point; observing the marking situation of the characteristic points and calculating the distance between the fault point and the monitoring device according to the finally determined reference point to complete the fault location. The present invention utilizes the mutation characteristics presented by the reflected traveling wave of the fault on the waveform diagram, and can achieve fast and accurate fault location through simple point - selection judgment, avoiding the complex manual calculation and verification process in the traditional single - end location method. The operation is simplified to point - selection and judgment, greatly reducing the location time and improving the location accuracy, enabling ordinary personnel in this field to perform transmission line fault location.

Description

Technical Field

[0001] The present invention belongs to the technical field of power monitoring, and particularly relates to a single-end fault location method and device for transmission line fault points based on the traveling wave method. Background Art

[0002] A transmission line fault refers to problems such as short circuit, line tripping, and line power outage under the action of various factors. Generally, it can be divided into transient faults and permanent faults. A transient fault is that after the relay protection operates to disconnect the power supply, the arc at the fault point extinguishes itself, the insulation medium (such as insulators, arresters, etc.) resumes its strength again, and the fault is eliminated automatically. At this time, if the circuit breaker is reclosed, normal power supply can be restored, that is, the reclosing is successful; if the fault is not eliminated in time, when the circuit breaker is reclosed at this time, the line will trip again, that is, the reclosing fails. The reclosing will be started immediately after the line fault, and after a delay of 0.5 s to 1.0 s, a reclosing pulse is sent to close the circuit breaker. A permanent fault is that after the line power supply is disconnected, the insulation strength at the fault point cannot be restored, the fault point still exists, and even if the circuit breaker is reclosed, it will be disconnected again by the relay protection device, and then there will be no automatic reclosing.

[0003] After a transmission line fails, high-frequency traveling wave current and power frequency fault current will be generated on the line. According to the wavefront polarity and waveform characteristics of the current waveform, the fault section and fault type where the fault point occurs can be confirmed; according to the time when the traveling wave current reaches the distributed device, the specific tower position where the fault point occurs can be calculated. As Figure 1 shown, assume that point M is the monitoring point equipped with a monitoring terminal, and the fault occurs at point C between substation A and point M. Then the traveling wave generated by the fault point propagates along the transmission line towards substation B at a speed of v, and reflects back and forth between substation B and fault point C. The monitoring terminal at point M records the moment when the fault traveling wave passes through this monitoring point, and a single-end traveling wave fault location system can be formed. The distance L between fault point C and monitoring point M = (t3 - t2)v / 2, where t3 is the moment when the fault traveling wave reaches the monitoring terminal M for the third time after being reflected by substation B and the fault point, and t2 is the moment when the fault traveling wave reaches the monitoring terminal M for the second time.

[0004] However, the traditional single-end traveling wave fault location method has a long location time and poor accuracy. For the traveling wave waveform with the superposition of multiple reflection waveforms, it is difficult to distinguish the wavefront of the reflection waveform, and the selection of t2 and t3 is a major problem. And the operation and maintenance personnel often need to obtain the fault diagnosis result in a short time. Therefore, it is extremely important to provide a fast and simple single-end location method. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a single - end fault location method and device for transmission line fault points based on the traveling - wave method, so as to reduce the difficulty of manual point selection, optimize the fault point location process, not rely on the personal experience of operation and maintenance personnel, and enable ordinary personnel in this field to perform fast and accurate fault location operations.

[0006] The technical solution provided by the present invention is as follows:

[0007] A single - end fault location method for transmission line fault points based on the traveling - wave method, the transmission line includes a monitoring device for receiving fault traveling waves, and a head - end substation and a tail - end substation located on the left and right sides of the monitoring device respectively; the method includes the steps:

[0008] S1. Obtain the waveform diagram of the fault traveling wave in real time through the monitoring device;

[0009] S2. Judge whether the fault point is on the left or right side of the monitoring device, and calibrate the traveling - wave velocity:

[0010] First, according to the distance between the monitoring device and the head - end substation and the ideal wave velocity, calculate the time t1 required for the fault traveling wave to propagate from the monitoring device to the head - end substation. Then, find the position point with a time difference of 2t1 from T0 in the waveform diagram, and judge whether this position point or its vicinity is a waveform mutation point. If so, the fault point is on the right side of the monitoring device, otherwise it is on the left side; when the fault point is on the left side of the monitoring device, regard the original head - end substation as the tail - end substation, and regard the original tail - end substation as the head - end substation; when calibrating the wave velocity, find the waveform mutation point in the waveform diagram, and take half of the time difference between this waveform mutation point and T0 as the time for the fault traveling wave to propagate from the monitoring device to the head - end substation, and calculate the actual wave velocity of the fault traveling wave according to the distance between the monitoring device and the head - end substation;

[0011] S3. Determine and mark the waveform mutation point T0 corresponding to when the traveling wave first arrives at the monitoring device on the waveform diagram;

[0012] S4. Select the waveform mutation point closest to T0 on the waveform diagram as the reference point;

[0013] S5. Regard the reference point as T2 or T8; T2 represents the time point when the fault traveling wave propagates from the fault point to the head - end substation, then reflects back to the fault point and continues to propagate to the monitoring device; T8 represents the time point when the fault traveling wave propagates from the fault point to the tail - end substation, then reflects back to the fault point and continues to propagate to the monitoring device;

[0014] S6. According to the time difference between T2 or T8 and T0, calculate the time t required for the traveling wave to directly propagate from the fault point to the monitoring device, and further deduce and mark other multiple characteristic points of the refracted and reflected traveling waves received by the monitoring device on the waveform diagram;

[0015] S7. If all the corresponding points among the multiple characteristic points on the waveform diagram are mutation points, the selected reference point is the actual T2 or T8. The obtained time t is the actual time required for the traveling wave to directly propagate from the fault point to the monitoring device. Then, the distance from the fault point to the monitoring device is calculated based on the traveling wave velocity to achieve fault point location.

[0016] S8. Otherwise, other waveform mutation points are sequentially selected as reference points on the waveform diagram in the order of the distance from T0 from near to far, and steps S5 - S7 are repeated until the fault point location is completed.

[0017] Further, in step S5, when the fault point is on the right side of the monitoring device, T2 = 3t + 2t1, T8 = 2t2 - t, where t is the time required for the fault traveling wave to directly propagate from the fault point to the monitoring device, t1 is the time required for the fault traveling wave to propagate from the monitoring device to the head - end substation, and t2 is the time required for the fault traveling wave to propagate from the monitoring device to the end - end substation.

[0018] Further, in step S6, the other multiple characteristic points include:

[0019] The time point T3 when the fault traveling wave sequentially passes through "fault point - head - end substation - end - end substation - fault point - monitoring device";

[0020] The time point T4 when the fault traveling wave sequentially passes through "fault point - head - end substation - fault point - head - end substation - monitoring device";

[0021] The time point T5 when the fault traveling wave sequentially passes through "fault point - head - end substation - end - end substation - head - end substation - monitoring device";

[0022] The time point T6 when the fault traveling wave sequentially passes through "fault point - head - end substation - fault point - head - end substation - fault point - monitoring device";

[0023] The time point T7 when the fault traveling wave sequentially passes through "fault point - head - end substation - fault point - head - end substation - fault point - head - end substation - monitoring device".

[0024] Further, when the fault point is on the right side of the monitoring device, T3 = t + 2t1 + 2t2, T4 = 3t + 4t1, T5 = t + 4t1 + 2t2, T6 = 5t + 4t1, T7 = 5t + 6t1, where t is the time required for the fault traveling wave to directly propagate from the fault point to the monitoring device, t1 is the time required for the fault traveling wave to propagate from the monitoring device to the head - end substation, and t2 is the time required for the fault traveling wave to propagate from the monitoring device to the end - end substation.

[0025] Further, in step S6, the other multiple feature points further include:

[0026] The time point T9 when the fault traveling wave sequentially passes through "fault point - end substation - head substation - monitoring device";

[0027] The time point T10 when the fault traveling wave sequentially passes through "fault point - end substation - fault point - end substation - monitoring device";

[0028] The time point T11 when the fault traveling wave sequentially passes through "fault point - end substation - head substation - fault point - monitoring device";

[0029] The time point T12 when the fault traveling wave sequentially passes through "fault point - end substation - fault point - end substation - head substation - monitoring device";

[0030] The time point T13 when the fault traveling wave sequentially passes through "fault point - end substation - head substation - fault point - head substation - monitoring device".

[0031] Further, when the fault point is on the right side of the monitoring device, T9 = 2t1 + 2t2 - t, T10 = 4t2 - 3t, T11 = 2t1 + 2t2 + t, T12 = 2t1 + 4t2 - 3t, T13 = 4t1 + 2t2 + t, where t is the time required for the fault traveling wave to directly propagate from the fault point to the monitoring device, t1 is the time required for the fault traveling wave to propagate from the monitoring device to the head substation, and t2 is the time required for the fault traveling wave to propagate from the monitoring device to the end substation.

[0032] A single - end fault location device for a transmission line based on the above - mentioned method, comprising:

[0033] A waveform display module, configured to receive and display the fault traveling wave waveform acquired by the monitoring device;

[0034] A parameter setting module, configured to input the distances between the monitoring device and the head substation and the end substation, as well as the traveling wave velocity;

[0035] A fault point direction judgment module, configured to judge whether the fault point is on the left or right side of the monitoring device;

[0036] A wave velocity calibration module, configured to calculate and obtain the actual wave velocity of the fault traveling wave;

[0037] A reference point selection module, configured to allow the user to select a waveform mutation point as a reference point on the waveform graph;

[0038] A waveform automatic annotation module, configured to automatically annotate other multiple feature points calculated based on the selected reference point on the waveform graph;

[0039] The fault point distance output module is used to calculate and output the distance between the fault point and the monitoring device according to the finally determined reference point after the user observes the feature point marking situation.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] The present invention utilizes the mutation characteristics presented by the fault line wave reflection on the waveform diagram, and can achieve fast and accurate fault location through simple point selection and judgment, avoiding the complex manual calculation and verification processes in the traditional single-end location method. The operation is simplified to point selection and judgment, greatly reducing the location time, improving the location accuracy, and enabling ordinary personnel in this field to perform transmission line fault location. Description of the Drawings

[0042] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention.

[0043] Figure 1 It is a schematic diagram of the traditional single-end location method provided by an embodiment of the present invention;

[0044] Figure 2 It is a schematic diagram of the complete line wave reflection provided by an embodiment of the present invention;

[0045] Figure 3 It is a schematic diagram of the left-traveling wave reflection provided by an embodiment of the present invention;

[0046] Figure 4 It is a schematic diagram of the right-traveling wave reflection provided by an embodiment of the present invention;

[0047] Figure 5 It is a schematic diagram of the transmission line provided by an embodiment of the present invention;

[0048] Figure 6 It is a fault traveling wave diagram of a certain line obtained by the monitoring device provided by an embodiment of the present invention;

[0049] Figure 7 It is a schematic diagram of the selection of mutation point 1 provided by an embodiment of the present invention;

[0050] Figure 8 It is a waveform annotation diagram of T0~T13 after calculating mutation point 1 as T2 provided by an embodiment of the present invention;

[0051] Figure 9 It is a waveform annotation diagram of T0~T13 after calculating mutation point 1 as T8 provided by an embodiment of the present invention;

[0052] Figure 10It is a schematic diagram for judging whether the fault point is on the left / right side of the monitoring device provided by an embodiment of the present invention;

[0053] Figure 11 It is a schematic flow diagram of a single-end fault location method for a transmission line fault point provided by an embodiment of the present invention. Detailed implementation manners

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0055] I. Traveling wave reflection process

[0056] The complete traveling wave reflection process is relatively complex, but it is always the superposition of two traveling wave reflections. As Figure 2 shown, they are respectively the traveling wave propagating from the fault point to the head-end substation and the traveling wave propagating from the fault point to the tail-end substation during a fault, hereinafter simply referred to as the left traveling wave and the right traveling wave. The reflection and refraction processes of the left traveling wave and the right traveling wave are respectively as Figure 3 and Figure 4 shown, and the waveform passing through the fault point is represented by a dashed line. Considering the reflection and refraction losses, only the waveforms with 5 or fewer reflection and refraction times are calculated.

[0057] II. Analysis of single-end location algorithm

[0058] As Figure 5 shown, assume that the transmission line consists of four nodes: "head-end substation - monitoring device - fault point - tail-end substation", and is divided into three parts: t1, t, and t2 - t (length / standard traveling wave speed). Among them, t1 and t2 are known (t1 is the time for the traveling wave to propagate from the monitoring device to the head-end substation, and t2 is the time for the traveling wave to propagate from the monitoring device to the tail-end substation), and there is only one unknown t, that is, the propagation time of the traveling wave from the fault point to the monitoring device. As long as t is determined, the time when the monitoring device receives each reflection and refraction waveform can also be determined (i.e., the time of the mutation point on the waveform).

[0059] Referring to Figure 3 for the left traveling wave reflection and refraction process, then there is

[0060] T0 = t, the trigger point time, that is, the fault point - monitoring device

[0061] T1 = t + 2*t1, the time for wave speed calibration, that is, the fault point - head-end substation - monitoring device

[0062] T2 = 3*t + 2*t1, Fault point - First substation - Fault point - Monitoring device

[0063] T3 = t + 2*t1 + 2*t2, Fault point - First end - Fault point - Last end - Fault point - Monitoring device

[0064] T4 = 3*t + 4*t1, Fault point - First end - Fault point - First end - Monitoring device

[0065] T5 = t + 4*t1 + 2*t2, Fault point - First end - Last end - First end - Monitoring device

[0066] T6 = 5*t + 4*t1, Fault point - First end - Fault point - First end - Fault point - Monitoring device

[0067] T7 = 5*t + 6*t1, Fault point - First end - Fault point - First end - Fault point - First end - Monitoring device

[0068] Reference Figure 4 in the right - hand wave - reflection process, then there is

[0069] T8 = 2*t2 - t, Fault point - Last end - Fault point - Monitoring device

[0070] T9 = 2*t1 + 2*t2 - t, Fault point - Last end - First end - Monitoring device

[0071] T10 = 4*t2 - 3*t, Fault point - Last end - Fault point - Last end - Monitoring device

[0072] T11 = 2*t1 + 2*t2 + t, Fault point - Last end - First end - Fault point - Monitoring device

[0073] T12 = 2*t1 + 4*t2 - 3*t, Fault point - Last end - Fault point - Last end - First end - Monitoring device

[0074] T13 = 4*t1 + 2*t2 + t, Fault point - Last end - First end - Fault point - First end - Monitoring device

[0075] In the above calculation, t1 = distance from the monitoring device to the head substation / traveling wave speed, t2 = distance from the monitoring device to the end substation / traveling wave speed. The distances from the head substation and the end substation to the monitoring device are known, and the traveling wave speed is 296 m / us. Then the only variable among T1~T13 is t. If t can be determined, then T1~T13 can also be determined. The mutation point closest to T0 can be taken from the waveform diagram received by the monitoring device, and this point must be one of T1, T2, and T8. T1 can be directly determined by t1. After excluding T1, assuming this mutation point is T2 / T8, T0~T13 can be directly solved and marked on the original waveform diagram. Manually, only need to judge whether T0~T13 are mutation points on the waveform. If so, the positioning is completed; if not, re-select the mutation point as T2 / T8. For easy understanding, the following is an example.

[0076] As Figure 5 shown, it is the traveling wave diagram of line fault obtained by a certain monitoring device. Among them, T0 is the time difference when the waveform first reaches the monitoring device from the fault point. Since the time of the fault occurrence is unknown, T0 cannot be directly obtained from the figure. The time parameter that can be directly obtained in the figure is the time difference between the waveform after reflection and refraction and the first wave. The reason is that every time the waveform is reflected and refracted and passes through the monitoring device, a new waveform will be superimposed on the original waveform, forming a mutation point. The time difference between this mutation point and the wave head is the time difference between T1~T13 and T0.

[0077] According to Figure 3 and Figure 4 it can be known that the time point closest to the wave head of the left traveling wave is T1, but the time difference 2*t1 between T1 and T0 is a known quantity and t cannot be determined, so T2 is selected; the time point closest to the wave head of the right traveling wave is T8. From Figure 6 it can be seen that T0 is the wave head, and T1 is the mutation point at a distance of 2t1 from the wave head. Then except for T1, the mutation point closest to T0 is T2 or T8. Determining the position of this mutation point means determining the value of t and the position of the fault point, and also determining the positions of T0~T13 in Figure 6 . Mark T1~T13 in Figure 6 and observe whether their positions are waveform mutation points, then it can be judged whether the value of t is correct and whether the diagnosis is successful.

[0078] Specifically, taking Figure 7 as an example, select mutation point 1 as T2 / T8. When calculating T0~T13 as T2, as Figure 8 shown, it can be seen from Figure 8 that except for T0~T3 which are mutation points, the waveforms at other time points do not have obvious mutations (the waveforms at some time points exceed the waveform length and are not shown in the figure). It can be seen that mutation point 1 is not T2. Then calculate T0~T13 with mutation point 1 as T8 asFigure 9 As shown, by comparing Figure 9 and Figure 8 , Figure 9 The T0 - T13 of [[reference]] (some time points exceed the waveform length and are not shown) is more consistent with the mutation points of the waveform. Taking mutation point 1 as T8 is more in line with the waveform characteristics. If taking mutation point 1 as T2 / T8 does not conform to the waveform characteristics, mutation point 1 may be a mutation of the waveform itself, rather than being generated by the superposition after waveform reflection and refraction. Then, other points such as point 2, point 3, point 4, etc. can be taken after mutation point 1. The method is the same as the above process and will not be elaborated here.

[0079] The above operations can be calculated through the diagnostic platform. The manual operation only requires the following steps:

[0080] ① Determine whether the fault point is on the left / right side of the monitoring device;

[0081] ② Select mutation points 1, 2, 3......

[0082] ③ Check the fitting situation between T0 - T13 and the waveform characteristics;

[0083] ④ Complete the positioning.

[0084] Among them, regarding how to judge whether the fault point is on the left / right side of the monitoring device, taking Figure 10 as an example, first calculate t1 and t2 according to the line lengths from the monitoring device to the head - end substation and the tail - end substation. Then find the positions with time differences of 2t1 and 2t2 from T0 in the waveform diagram. It can be seen from the figure that at T0 + 2t1 (or its vicinity) is the mutation point, which just corresponds to the time point (i.e., T1) when the fault traveling wave passes through the monitoring device and is reflected back to the monitoring device by the left - hand substation after passing through the monitoring device when the fault point is on the right side of the monitoring device. Therefore, the fault occurs on the right side of the monitoring device. If the point at T0 + 2t1 is not a mutation point, then the fault occurs on the left side of the monitoring device. In addition, at the same time, the propagation speed of the fault traveling wave can be calibrated according to the actual time difference between mutation point T1 and T0 (the previously calculated 2t1 is the theoretical value calculated under the ideal light speed).

[0085] The overall process of the single - end fault point location method provided in this embodiment is as Figure 11 shown. Correspondingly, this embodiment also provides a single - end fault point location device for transmission lines based on the traveling - wave method, which mainly includes:

[0086] A waveform display module, configured to receive and display the fault traveling - wave waveform acquired by the monitoring device;

[0087] A parameter setting module, configured to input the distances between the monitoring device and the head - end substation and the tail - end substation, as well as the traveling - wave speed;

[0088] The fault point direction judgment module is used to judge whether the fault point is on the left or right side of the monitoring device;

[0089] The wave velocity calibration module is used to calculate and obtain the actual wave velocity of the fault traveling wave;

[0090] The reference point selection module is used for the user to select the waveform mutation point as the reference point on the waveform diagram;

[0091] The waveform automatic annotation module is used to automatically annotate multiple other characteristic points calculated based on the selected reference point on the waveform diagram;

[0092] The fault point distance output module is used to calculate and output the distance between the fault point and the monitoring device according to the finally determined reference point after the user observes the annotation situation of the characteristic points.

[0093] The above product can execute the single - end fault point location method, has the corresponding functional modules and beneficial effects of the method. For the technical details not described in detail in this part, reference can be made to the above - provided single - end fault point location method.

[0094] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of brevity, they are not provided in detail; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A single - end fault location method for transmission line fault points based on the traveling - wave method. The transmission line includes a monitoring device for receiving fault traveling waves, and a head - end substation and a tail - end substation located on the left and right sides of the monitoring device respectively. It is characterized in that, Including the steps: S1. Obtain the waveform diagram of the fault traveling wave in real time through the monitoring device; S2. Determine whether the fault point is on the left or right side of the monitoring device, and calibrate the traveling wave velocity: First, calculate the time t1 required for the fault traveling wave to propagate from the monitoring device to the head-end substation according to the distance between the monitoring device and the head-end substation and the ideal wave velocity. Then, find the position point with a time difference of 2t1 from T0 in the waveform diagram, and determine whether this position point or its vicinity is a waveform mutation point. If so, the fault point is on the right side of the monitoring device; otherwise, it is on the left side. When the fault point is on the left side of the monitoring device, regard the original head-end substation as the end substation and the original end substation as the head-end substation. When calibrating the wave velocity, find the waveform mutation point in the waveform diagram, and take half of the time difference between this waveform mutation point and T0 as the time for the fault traveling wave to propagate from the monitoring device to the head-end substation, and calculate the actual wave velocity of the fault traveling wave according to the distance between the monitoring device and the head-end substation; S3. Determine and mark the waveform mutation point T0 corresponding to when the traveling wave first arrives at the monitoring device on the waveform diagram; S4. Select the waveform mutation point closest to T0 on the waveform diagram as the reference point; S5. Regard the reference point as T2 or T8; T2 represents the time point when the fault traveling wave propagates from the fault point to the head-end substation, then reflects back to the fault point and continues to propagate to the monitoring device; T8 represents the time point when the fault traveling wave propagates from the fault point to the end substation, then reflects back to the fault point and continues to propagate to the monitoring device; S6. Calculate the time t required for the traveling wave to directly propagate from the fault point to the monitoring device according to the time difference between T2 or T8 and T0, and then deduce and mark other multiple characteristic points of the reflected and refracted traveling wave received by the monitoring device on the waveform diagram; S7. If all the corresponding points of these multiple characteristic points on the waveform diagram are mutation points, then the selected reference point is the actual T2 or T8, and the obtained time t is the actual time required for the traveling wave to directly propagate from the fault point to the monitoring device. Then, calculate the distance from the fault point to the monitoring device according to the traveling wave velocity to achieve fault point location; S8. Otherwise, sequentially select other waveform mutation points as the reference point on the waveform diagram from the closest to T0, and repeat steps S5 - S7 until the fault point location is completed.

2. The single - end fault location method for transmission lines according to claim 1, wherein, In step S5, when the fault point is on the right side of the monitoring device, T2 = 3t + 2t1, T8 = 2t2 - t, where t is the time required for the fault traveling wave to directly propagate from the fault point to the monitoring device, t1 is the time required for the fault traveling wave to propagate from the monitoring device to the head-end substation, and t2 is the time required for the fault traveling wave to propagate from the monitoring device to the end substation.

3. The single - end fault location method for transmission lines as claimed in claim 1, wherein In step S6, the other multiple characteristic points include: The time point T3 when the fault traveling wave passes through "fault point - head-end substation - end substation - fault point - monitoring device" in sequence; The time point T4 when the fault traveling wave passes through "fault point - head-end substation - fault point - head-end substation - monitoring device" in sequence; The time point T5 when the fault traveling wave passes through "fault point - head-end substation - end substation - head-end substation - monitoring device" in sequence; The time point T6 when the fault traveling wave passes through "fault point - head substation - fault point - head substation - fault point - monitoring device" in sequence; The time point T7 when the fault traveling wave passes through "fault point - head substation - fault point - head substation - fault point - head substation - monitoring device" in sequence.

4. The single-end fault location method for a transmission line according to claim 3, characterized in that, When the fault point is on the right side of the monitoring device, T3 = t + 2t1 + 2t2, T4 = 3t + 4t1, T5 = t + 4t1 + 2t2, T6 = 5t + 4t1, T7 = 5t + 6t1, where t is the time required for the fault traveling wave to directly propagate from the fault point to the monitoring device, t1 is the time required for the fault traveling wave to propagate from the monitoring device to the head substation, and t2 is the time required for the fault traveling wave to propagate from the monitoring device to the end substation.

5. The single-end fault location method for transmission lines according to claim 1, wherein In step S6, the other multiple characteristic points further include: The time point T9 when the fault traveling wave passes through "fault point - end substation - head substation - monitoring device" in sequence; The time point T10 when the fault traveling wave passes through "fault point - end substation - fault point - end substation - monitoring device" in sequence; The time point T11 when the fault traveling wave passes through "fault point - end substation - head substation - fault point - monitoring device" in sequence; The time point T12 when the fault traveling wave passes through "fault point - end substation - fault point - end substation - head substation - monitoring device" in sequence; The time point T13 when the fault traveling wave passes through "fault point - end substation - head substation - fault point - head substation - monitoring device" in sequence.

6. The single - end fault location method for transmission lines according to claim 5, characterized in that, When the fault point is on the right side of the monitoring device, T9 = 2t1 + 2t2 - t, T10 = 4t2 - 3t, T11 = 2t1 + 2t2 + t, T12 = 2t1 + 4t2 - 3t, T13 = 4t1 + 2t2 + t, where t is the time required for the fault traveling wave to directly propagate from the fault point to the monitoring device, t1 is the time required for the fault traveling wave to propagate from the monitoring device to the head substation, and t2 is the time required for the fault traveling wave to propagate from the monitoring device to the end substation.

7. A single - end fault location device for transmission lines based on the method according to any one of claims 1 to 6, characterized in that, Including: A waveform display module for receiving and displaying the fault traveling wave waveform acquired by the monitoring device; A parameter setting module for inputting the distances between the monitoring device and the head substation and the end substation, as well as the traveling wave velocity; A fault point direction judgment module for judging whether the fault point is on the left or right side of the monitoring device; A wave velocity calibration module for calculating and obtaining the actual wave velocity of the fault traveling wave; A reference point selection module for the user to select a waveform mutation point as a reference point on the waveform graph; A waveform automatic annotation module for automatically annotating other multiple characteristic points deduced based on the selected reference point on the waveform graph; A fault point distance output module for calculating and outputting the distance between the fault point and the monitoring device according to the finally determined reference point after the user observes the annotation situation of the characteristic points.

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