System and method for judging branch where overhead line system fault is located

Abstract

The invention discloses a system and method for judging a branch where a contact network fault is located, and the system and method are applied to a contact network with branches, and the method comprises the steps: obtaining the current if of a first branch, and transmitting the current data of the first branch to a measurement and control device; acquiring a second branch current ib, and sending the second branch current to the measurement and control device; and acquiring a feeder protection action signal, calculating the first branch current if data and the second branch current ib data at the time corresponding to the feeder protection action moment, and judging whether the fault position of the contact network is in the second branch or not. The method is used for the situation that the fault position of the overhead contact system with branches cannot be determined only according to the fault distance measurement result, when the overhead contact system breaks down, the judgment result of the method is combined with the feeder protection fault distance measurement result, and the accurate position of the fault of the overhead contact system can be rapidly, accurately and automatically judged.

Description

Technical Field

[0001] The present application relates to the field of measurement and control of traction power supply for electrified railways, and in particular to a system and method for determining the branch where a contact network fault is located. Background Art

[0002] The feeder of the electrified railway traction substation (including the switch substation if not specified below) supplies power to the overhead line through the power supply line. Since the overhead line is arranged in the open air, has a complex structure, and is in high-speed sliding contact with the pantograph of the electric locomotive or EMU, it has frequent faults, and there is no backup for the overhead line equipment. If the fault cannot be quickly eliminated after it occurs, a long power outage will have a serious impact on the railway transportation order.

[0003] Catenary faults are divided into transient faults and permanent faults. Transient faults can be quickly restored to power supply through automatic reclosing, but the fault location is often the weak point of the catenary, and hidden dangers need to be found and eliminated to prevent the fault from recurring or developing into a permanent fault. For permanent faults, it is even more important to quickly find the fault location in order to eliminate the fault and restore the catenary power supply as soon as possible. Therefore, after a catenary fault occurs, quickly determining the fault location is the premise and key to restoring power supply as soon as possible and reducing fault losses.

[0004] At present, the feeder protection devices of traction substations are all equipped with a built-in fault distance measurement function. When a fault occurs in the contact network, the feeder protection device will operate and disconnect the feeder circuit breaker. At the same time, it will calculate the distance from the fault location to the installation location of the protection device based on data such as the bus voltage, feeder current or suction line current at the time of the fault, thereby determining the location of the contact network fault, so that the power supply dispatcher can guide the contact network maintenance personnel to quickly rush to the fault site to deal with the fault.

[0005] In fact, the access points where the power supply line is connected to the contact network are not all located at the branch line at the end of the contact network power supply section. In many cases, the power supply line T is connected to the contact network, and there are contact networks on both sides of the access point. When a fault occurs in the contact network, the fault distance indicated by the feeder protection device may correspond to different positions of the contact networks on both sides of the access point, and it is impossible to determine on which side of the access point the fault is located.

[0006] There are also some contact networks with branches, which are common in railway hubs, stations or railways with branches. One fault distance may correspond to two or more contact network locations, and it is impossible to determine which contact network branch the fault is in.

[0007] For the situation where the contact networks on both sides of the contact point on the T-type contact network or on different branches of the branch-type contact network are long, if a fault occurs, the fault distance does not correspond to the only fault location, and the contact network maintenance personnel are required to rush to different locations to check the contact network, or arrange multiple repair teams to go to different locations, which will extend the time for the contact network to restore power supply, seriously affecting the power supply safety and driving order. Summary of the invention

[0008] In view of the above-mentioned deficiencies in the prior art, the system and method for determining the branch where a contact network fault is located provided by the present invention solve the above-mentioned problems in the prior art.

[0009] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a branch determination system for a contact network fault, applied to a contact network with branches, the current transformer and the circuit breaker in the traction substation lead out a first branch from the busbar, and connect it to the contact network outside the traction substation at its non-end, and select the contact network branch on either side of the connection point between the first branch and the contact network as the second branch;

[0010] The system includes a first branch current acquisition module, a second branch current acquisition module, a feeder protection action signal acquisition module, a transmission channel and a measurement and control device;

[0011] The first branch current acquisition module and the feeder protection action signal acquisition module are connected to the measurement and control device, and the second branch current acquisition module is connected to the measurement and control device through a transmission channel;

[0012] The first branch current acquisition module is used to acquire current data of the first branch;

[0013] The second branch current acquisition module is used to acquire current data of the second branch;

[0014] The transmission channel is used for data transmission between the second branch current module and the measurement and control device;

[0015] The feeder protection action signal acquisition module is used to acquire the feeder protection action signal as a condition for starting the fault branch judgment;

[0016] The measuring and controlling device is used to calculate the current data of the first branch and the second branch at the corresponding time under the condition of starting the fault branch judgment, and give the judgment result of whether the contact network fault is in the second branch.

[0017] Furthermore, the measurement and control device includes a CPU module, and an analog input module, a switch input module, a power supply module, a communication module and a human-machine interface module, all of which are connected to the CPU module.

[0018] Further, the transmission channel is a cable, an optical fiber or a wireless communication network;

[0019] When the current data of the second branch is transmitted in the form of an analog signal, the transmission channel is a cable;

[0020] When the current data of the second branch is transmitted in the form of a digital signal, the transmission channel is an optical fiber;

[0021] When the current data of the second branch is transmitted in the form of a digital signal with a time stamp, the transmission channel is a wireless communication network.

[0022] Furthermore, when the current data of the second branch is transmitted in the form of a digital signal with a time stamp, a data terminal is provided on the current acquisition side of the second branch, and the clock of the data terminal is synchronized with the clock of the measurement and control device.

[0023] A method for determining a branch where a contact network fault is located comprises the following steps:

[0024] S1, respectively acquiring current data of the first branch and the second branch through the first branch current acquisition module and the second branch current acquisition module, and transmitting the data to the measurement and control device;

[0025] S2. Obtaining a feeder protection action signal through a feeder protection action signal acquisition module, and detecting whether the feeder protection is actuated;

[0026] If yes, proceed to step S3;

[0027] If not, return to step S1;

[0028] S3. Calculate the current data of the first branch and the second branch through the measurement and control device and compare them, and give a determination result of whether the contact network fault is in the second branch.

[0029] Furthermore, in step S1, the current data of the first branch is obtained by directly obtaining it from the output terminal of the current transformer installed on the first branch, or indirectly obtaining it through a device or network related to the output of the current transformer installed on the first branch;

[0030] The current data of the second branch is obtained by: obtaining from the output end of the current transformer installed on the second branch, or obtaining after the output of the current transformer installed on the second branch is processed by a data terminal.

[0031] Furthermore, in step S2, the method for obtaining the feeder protection action signal includes:

[0032] Acquire a contact signal or a level signal representing a protection action from a feeder protection device as a feeder protection action signal;

[0033] Obtain feeder protection action signals from messages via the communication network;

[0034] According to the acquired current data of the first branch and the second branch, a feeder protection action signal is calculated and determined to be generated.

[0035] Furthermore, the step S3 is specifically as follows:

[0036] At the moment of feeder protection action, if the current data of the second branch is greater than 0.5 times the current data of the first branch, it is determined that the contact network fault causing the feeder protection action is located in the second branch, otherwise it is not in the second branch.

[0037] Furthermore, the step S3 is specifically as follows:

[0038] The current data of the first branch and the current data of the second branch within a period of time before and after the feeder protection action is used as the basis for judgment, and the similarity of the data curve shapes of the current data of the first branch and the second branch within the time range in the corresponding time series is compared, and it is determined whether the similarity is greater than the set threshold. If so, it is determined that the contact network fault causing the feeder protection action is located in the second branch, otherwise it is not in the second branch.

[0039] Furthermore, the calculation formula for the similarity of the data curve shapes of the current data of the first branch and the second branch in the corresponding time series is:

[0040]

[0041] Where d is the minimum Euclidean distance between the current data if of the first branch in the corresponding time series and the current data ib of the second branch after translation along the Y axis, which is used to measure the similarity of the two curves. v is the translation of the second branch current ib along the Y axis, v∈[min(if-ib),max(if-ib)], j is the time point, and n is the total length of the time series.

[0042] The beneficial effects of the present invention are:

[0043] The present invention provides a system and method for determining the branch where a contact network fault is located with relatively less equipment investment, which is used in the case where the fault distance corresponds to not a unique contact network location. When a contact network fault occurs and the substation feeder protection is actuated, it is quickly determined whether the fault is located in a specific contact network branch. The determination result is combined with the fault distance measurement result of the feeder protection to automatically and quickly determine the exact location of the contact network fault, thereby providing conditions for timely handling of the contact network fault, thereby shortening the contact network fault power outage time and reducing the loss caused by the fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram of a system for determining a branch where a contact network fault is located provided by the present invention.

[0045] Figure 2 This is a structural diagram of the branch determination system for the contact network fault provided by the present invention.

[0046] Figure 3 This is a schematic diagram of the structure of the measurement and control device provided by the present invention.

[0047] Figure 4 A schematic diagram of obtaining second branch current data provided by the present invention.

[0048] Figure 5 A flow chart of a method for determining a branch where a contact network fault is located provided by the present invention. DETAILED DESCRIPTION

[0049] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0050] Embodiment 1:

[0051] like Figure 1 As shown, an embodiment of the present invention provides a system for determining the branch where a contact network fault is located, which is applied to a contact network with branches. The current transformer and the circuit breaker in the traction substation lead out a first branch from the busbar, which is connected to the contact network outside the traction substation at its non-end, and the contact network branch on either side of the connection point between the first branch and the contact network is selected as the second branch.

[0052] like Figure 2 As shown, the contact network fault branch determination system in the embodiment of the present invention includes a first branch current acquisition module, a second branch current acquisition module, a feeder protection action signal acquisition module, a transmission channel and a measurement and control device; the first branch current acquisition module and the feeder protection action signal module are connected to the measurement and control device, and the second branch current acquisition module is connected to the measurement and control device through the transmission channel; the first branch current acquisition module and the feeder protection action signal acquisition module are connected to the measurement and control device, and the second branch current acquisition module is connected to the measurement and control device through the transmission channel; the first branch current acquisition module is used to obtain current data of the first branch; the second branch current acquisition module is used to obtain current data of the second branch; the transmission channel is used for data transmission between the second branch current module and the measurement and control device; the feeder protection action signal acquisition module is used to obtain the feeder protection action signal as a condition for starting the fault branch determination; the measurement and control device is used to calculate the current data of the first branch and the second branch at the corresponding time under the condition of starting the fault branch determination, and give a determination result of whether the contact network fault is in the second branch.

[0053] For a contact network with branches, the exact location of the contact network fault cannot be determined based only on the bus voltage and feeder current data measured in the traction substation, as the fault distance does not correspond to a unique location. Therefore, in this embodiment, by collecting the current of a selected contact network branch, it is possible to determine whether the fault is located in the selected contact network branch, and then determine the exact location of the contact network fault based on the fault distance measurement result of the feeder protection device.

[0054] In this embodiment, the measurement and control device is the core of the system and is used to store, calculate and manage data, such as Figure 3 The figure shows the structure of a measurement and control device, which includes a CPU module, and an analog input module, a switch input module, a power supply module, a communication module and a human-machine interface module all connected to the CPU module.

[0055] Specifically, in the structure of the above-mentioned measurement and control device, the power supply module is used to provide the power required for the operation of the measurement and control device, the analog input module is used to collect the current data of the first branch and / or the second branch input in the form of analog quantity; the switch input module is used to collect the feeder protection action signal input in the form of switch quantity; the communication module is used to communicate and exchange data with the traction substation integrated automation system, the dispatching automation system, and the data terminal; the CPU module is used to calculate and determine the faulty branch; store programs, data and information, and control the work flow of the device.

[0056] In this embodiment, the current data of the first branch acquired by the first branch current acquisition module is the current data output by the secondary winding of the traction substation current transformer. In implementation, the secondary winding of the feeder current transformer can be directly connected to the analog input module of the measurement and control device.

[0057] In another embodiment of the present invention, the current data of the first branch can be obtained by connecting the communication module of the measurement and control device to the integrated automation system of the traction substation, and obtaining the current data of the first branch measured by the feeder protection device through network messages.

[0058] In an embodiment of the present invention, the second branch current data acquisition module acquires the current data of the second branch, a second branch current transformer is set on the contact network of the second branch near the node position, and the acquired second branch current data is sent to the measurement and control device in the traction substation through the transmission channel; specifically, when acquiring the second branch current, the polarity of the second branch current transformer should be kept consistent with the polarity of the first branch current transformer.

[0059] In this embodiment, according to the distance between the second branch current transformer installed on the contact network and the measurement and control device installed in the traction substation, the transmission channel is a cable, an optical fiber or a wireless communication network.

[0060] When the distance between the second branch current transformer and the measurement and control device is short, the transmission channel uses a cable, the second branch current data is transmitted in the form of an analog signal, and the secondary winding output of the second branch current transformer is directly connected to the analog input module of the measurement and control device.

[0061] When the distance between the second branch current transformer and the measurement and control device is far, optical fiber is used as the transmission channel; the second branch current data is transmitted in the form of a digital signal, and a data terminal is set near the second branch current transformer to convert the analog signal output by the secondary winding of the second branch current transformer into a digital signal, and the digital signal is transmitted to the measurement and control device through optical fiber.

[0062] In an optional embodiment of the present invention, when the transmission channel is an optical fiber, the second branch current transformer adopts an electronic current transformer with digital output, which is transmitted to the measurement and control device via the optical fiber without setting a data terminal.

[0063] When the distance between the second branch current transformer and the measurement and control device is far and it is inconvenient to set up an optical fiber transmission channel, a wireless communication network is used as the transmission channel, and the second branch current data is transmitted to the measurement and control device in the form of a time-stamped digital signal through the wireless communication network.

[0064] In this embodiment, when the current data of the second branch is transmitted in the form of a digital signal with a time stamp, a data terminal is provided on the current acquisition side of the second branch, and the clock of the data terminal is synchronized with the clock of the measurement and control device.

[0065] Specifically, in this embodiment, Figure 4 As shown, a data terminal is arranged near the current transformer of the second branch, and a wireless communication module 2 and a wireless communication module 1 are arranged at the data terminal and the measurement and control device respectively. The wireless communication module 2 and the wireless communication module 1 communicate with each other through a wireless communication network, so that the data terminal and the measurement and control device exchange data through a wireless network transmission channel.

[0066] Due to the uncertainty of wireless communication data transmission delay, in order to ensure that the first branch current and the second branch current involved in the calculation are data at the same time, the following processing method is adopted in this embodiment: the data terminal and the measurement and control device respectively set system clocks, the data terminal clock is synchronized with the measurement and control device clock, the data terminal and the measurement and control device respectively cache the second branch current data and the first branch current data in digital quantities with time stamps, when the measurement and control device collects the feeder protection action signal, it sends an instruction with a start time stamp to the data terminal by wireless communication, after receiving the instruction, the data terminal sends the current data of a period of time before and after the start time stamp in the cache to the measurement and control device by wireless communication, the measurement and control device calculates and determines whether the contact network fault is in the second branch according to the second branch current data and the first branch current data at the same time.

[0067] In the above process, the communication between the measurement and control device and the data terminal adopts the retrieval-reporting mechanism, and data is transmitted only when the measurement and control device needs it. The network load rate requirement is low, and the use of low-bandwidth wireless communication can also meet the requirements. Since wireless communication has a delay in transmitting data, there will be a delay in the measurement and control device reporting the fault branch judgment result. A delay of seconds is acceptable in engineering applications.

[0068] In an optional embodiment of the present invention, the wireless communication network used as a transmission channel may be a wireless public network or a wireless private network.

[0069] Embodiment 2:

[0070] The embodiment of the present invention provides a corresponding method for determining the branch where the overhead line fault is located based on the overhead line fault determination system proposed in Embodiment 1, such as Figure 5 As shown, the following steps are included:

[0071] S1, respectively acquiring current data of the first branch and the second branch through the first branch current acquisition module and the second branch current acquisition module, and transmitting the data to the measurement and control device;

[0072] S2. Obtaining a feeder protection action signal through a feeder protection action signal acquisition module, and detecting whether the feeder protection is actuated;

[0073] If yes, proceed to step S3;

[0074] If not, return to step S1;

[0075] S3. Calculate the current data of the first branch and the second branch through the measurement and control device and compare them, and give a determination result of whether the contact network fault is in the second branch.

[0076] In step S1 of the embodiment of the present invention, the current data of the first branch is obtained by directly obtaining it from the output terminal of the current transformer installed on the first branch, or indirectly obtaining it through a device or network related to the output of the current transformer installed on the first branch.

[0077] Specifically, the current data of the first branch acquired by the first branch current acquisition module is the current data output by the secondary winding of the current transformer of the traction substation. In implementation, the secondary winding of the feeder current transformer can be directly connected to the analog input module of the measurement and control device; it can also be automatically connected to the traction substation integrated system through the communication module of the measurement and control device, and the current data of the first branch measured by the feeder protection device can be obtained through network messages.

[0078] In step S1 of the embodiment of the present invention, the current data of the second branch is obtained by: obtaining from the current output terminal installed on the second branch, or obtaining after the output of the current transformer installed on the second branch is processed by a data terminal.

[0079] Specifically, in this embodiment, the second branch current data acquisition module acquires the current data of the second branch, a second branch current transformer is set on the contact network of the second branch near the node position, and the acquired second branch current data is sent to the measurement and control device in the traction substation through the transmission channel; specifically, when acquiring the second branch current, the polarity of the second branch current transformer should be kept consistent with the polarity of the first branch current transformer.

[0080] In this embodiment, according to the distance between the second branch current transformer installed on the contact network and the measurement and control device installed in the traction substation, the transmission channel is a cable, an optical fiber or a wireless communication network.

[0081] When the distance between the second branch current transformer and the measurement and control device is short, the transmission channel can use a cable, the second branch current data is transmitted in the form of an analog signal, and the secondary winding output of the second branch current transformer is directly connected to the analog input module of the measurement and control device.

[0082] When the distance between the second branch current transformer and the measurement and control device is far, the transmission channel can use optical fiber; the second branch current data is transmitted in the form of a digital signal, and a data terminal is set near the second branch current transformer to convert the analog signal output by the secondary winding of the second branch current transformer into a digital signal, and the digital signal is transmitted to the measurement and control device via optical fiber.

[0083] In an optional embodiment of the present invention, when the transmission channel is an optical fiber, the second branch current transformer adopts an electronic current transformer with digital output, which is transmitted to the measurement and control device via the optical fiber without setting a data terminal.

[0084] When the distance between the second branch current transformer and the measurement and control device is far and it is inconvenient to set up a transmission channel in the form of an optical fiber, a wireless communication network can be used as a transmission channel. The second branch current data is transmitted to the measurement and control device in the form of a digital signal with a time stamp through the wireless communication network.

[0085] Furthermore, when the current data of the second branch is transmitted in the form of a digital signal with a time stamp, such as Figure 4 As shown, a data terminal is arranged near the current transformer of the second branch, and a wireless communication module 2 and a wireless communication module 1 are arranged at the data terminal and the measurement and control device respectively. The wireless communication module 2 and the wireless communication module 1 communicate with each other through a wireless communication network, so that the data terminal and the measurement and control device exchange data through a wireless network transmission channel.

[0086] Due to the uncertainty of wireless communication data transmission delay, in order to ensure that the first branch current and the second branch current involved in the calculation are data at the same time, the following processing method is adopted in this embodiment: the data terminal and the measurement and control device respectively set system clocks, the data terminal clock is synchronized with the measurement and control device clock, the data terminal and the measurement and control device respectively cache the second branch current data and the first branch current data in digital quantities with time stamps, when the measurement and control device collects the feeder protection action signal, it sends an instruction with a start time stamp to the data terminal by wireless communication, after receiving the instruction, the data terminal sends the current data of a period of time before and after the start time stamp in the cache to the measurement and control device by wireless communication, the measurement and control device calculates and determines whether the contact network fault is in the second branch according to the second branch current data and the first branch current data at the same time.

[0087] In the above process, the communication between the measurement and control device and the data terminal adopts the retrieval-reporting mechanism, and data is transmitted only when the measurement and control device needs it. The network load rate requirement is low, and the use of low-bandwidth wireless communication can also meet the requirements. Since wireless communication has a delay in transmitting data, there will be a delay in the measurement and control device reporting the fault branch judgment result. A delay of seconds is acceptable in engineering applications.

[0088] In step S2 of the embodiment of the present invention, the method for obtaining a feeder protection action signal includes:

[0089] Acquire a contact signal or a level signal representing a protection action from a feeder protection device as a feeder protection action signal;

[0090] Obtain feeder protection action signals from messages via the communication network;

[0091] Or, based on the acquired current data of the first branch and the second branch, calculate and determine to generate a feeder protection action signal.

[0092] Step S3 of the embodiment of the present invention is specifically:

[0093] At the moment of feeder protection action, if the current data of the second branch is greater than 0.5 times the current data of the first branch, it is determined that the contact network fault causing the feeder protection action is located in the second branch, otherwise it is not in the second branch.

[0094] The above determination method is based on the premise that when the overhead contact network fails, the fault branch current is greater than the non-fault branch current. In fact, the operation and fault conditions of the overhead contact network are very complex and accidental. In large and long power supply sections or stations and hubs, the start-up and operation of multiple locomotives will cause the load current to be large. On the other hand, when a small current fault such as high-resistance grounding of the overhead contact network occurs, the fault current is small. Under the combined effect of the above two situations, the fault branch current may not be greater than 0.5 times the feeder current, resulting in the above determination algorithm to obtain an incorrect determination result.

[0095] In an embodiment of the present invention, another method for determining whether the contact network fault is in the second branch is provided. When a fault occurs, all branches through which the fault current passes have a current surge change process. If the fault is located in the second branch, the current in the second branch and the current in the first branch have similar change trends during the formation and development of the fault.

[0096] Based on this, step S3 of the embodiment of the present invention is specifically as follows:

[0097] The current data of the first branch and the current data of the second branch within a period of time before and after the feeder protection action is used as the basis for judgment, and the similarity of the data curve shapes of the current data of the first branch and the second branch within the time range in the corresponding time series is compared, and it is determined whether the similarity is greater than the set threshold. If so, it is determined that the contact network fault causing the feeder protection action is located in the second branch, otherwise it is not in the second branch.

[0098] In this embodiment, based on the similarity of the curve shapes of the second branch current ib and the first branch current if, the Euclidean distance algorithm with translation along the Y-axis is used to eliminate the influence of the uncertain difference in numerical values ​​between the second branch current ib and the first branch current if due to the diversion of other branches, which leads to the non-convergence of the calculation results.

[0099] Specifically, each sampling point on the second branch current ib curve is first translated upward along the Y axis for a distance v, and then the Euclidean distance with the first branch current if in the same time period is calculated, where v is the difference from the minimum to the maximum between the first branch current ib and the second branch current if in the data window, and the minimum Euclidean distance is found, which is the distance d between the two curves under the condition of maximum similarity matching. The specific calculation formula is:

[0100]

[0101] Where d is the minimum Euclidean distance between the current data if of the first branch in the corresponding time series and the current data ib of the second branch after translation along the Y axis, which is used to measure the similarity of the two curves. v is the translation of the second branch current ib along the Y axis, v∈[min(if-ib),max(if-ib)], j is the time point, and n is the total length of the time series.

[0102] It should be noted that the high-voltage equipment in the embodiment of the present application only adds one second branch current transformer, so as to achieve the purpose of determining the branch where the contact network fault is located with the least investment. Through the method provided by the present application, for contact networks with various branch numbers and node numbers, the location of the branch current transformer can be reasonably selected according to the specific situation, and the determination result can narrow the range of the contact network fault location, or more branch current transformers can be set according to the method provided by the present application to accurately determine the branch where the contact network fault is located.

[0103] It should be understood that a person skilled in the art would understand that a system may include more than Figure 2 and Figure 3 Fewer or more components than those shown in the figure, or including Figure 2 and Figure 3 The components shown are different components, Figure 2 and Figure 3 Only components that are more relevant to the implementation disclosed in the embodiments of the present application are shown.

[0104] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0105] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A system for determining the branch where a contact network fault is located, applied to a contact network with branches, characterized in that: The current transformer and the circuit breaker in the traction substation lead out a first branch from the busbar, and connect the contact network outside the traction substation at its non-end, and select the contact network branch on either side of the connection point between the first branch and the contact network as the second branch; The system includes a first branch current acquisition module, a second branch current acquisition module, a feeder protection action signal acquisition module, a transmission channel and a measurement and control device; The first branch current acquisition module and the feeder protection action signal acquisition module are connected to the measurement and control device, and the second branch current acquisition module is connected to the measurement and control device through a transmission channel; The first branch current acquisition module is used to acquire current data of the first branch; The second branch current acquisition module is used to acquire current data of the second branch; The transmission channel is used for data transmission between the second branch current module and the measurement and control device; The feeder protection action signal acquisition module is used to acquire the feeder protection action signal as a condition for starting the fault branch judgment; The measuring and controlling device is used to calculate the current data of the first branch and the second branch at the corresponding time under the condition of starting the fault branch judgment, and give the judgment result of whether the contact network fault is in the second branch.

2. The overhead line fault location branch determination system according to claim 1, characterized in that: The measurement and control device comprises a CPU module, and an analog quantity input module, a switch quantity input module, a power supply module, a communication module and a human-machine interface module, all of which are connected to the CPU module.

3. The overhead line fault location branch determination system according to claim 1, characterized in that: The transmission channel is a cable, an optical fiber or a wireless communication network; When the current data of the second branch is transmitted in the form of an analog signal, the transmission channel is a cable; When the current data of the second branch is transmitted in the form of a digital signal, the transmission channel is an optical fiber; When the current data of the second branch is transmitted in the form of a digital signal with a time stamp, the transmission channel is a wireless communication network.

4. The overhead line fault location branch determination system according to claim 3, characterized in that: When the current data of the second branch is transmitted in the form of a digital signal with a time stamp, a data terminal is provided on the current acquisition side of the second branch, and the clock of the data terminal is synchronized with the clock of the measurement and control device.

5. A method for determining a branch where a contact network fault is located based on the contact network fault branch determination system according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, respectively acquiring current data of the first branch and the second branch through the first branch current acquisition module and the second branch current acquisition module, and transmitting the data to the measurement and control device; S2. Obtaining a feeder protection action signal through a feeder protection action signal acquisition module, and detecting whether the feeder protection is actuated; If yes, proceed to step S3; If not, return to step S1; S3. Calculate the current data of the first branch and the second branch through the measurement and control device and compare them, and give a determination result of whether the contact network fault is in the second branch.

6. The method for determining the branch where the overhead line fault is located according to claim 5, characterized in that: In the step S1, the current data of the first branch is obtained by directly obtaining it from the output terminal of the current transformer installed on the first branch, or indirectly obtaining it through a device or network related to the output of the current transformer installed on the first branch; The current data of the second branch is obtained by: obtaining from the output end of the current transformer installed on the second branch, or obtaining after the output of the current transformer installed on the second branch is processed by a data terminal.

7. The method for determining the branch where the overhead line fault is located according to claim 5, characterized in that: In step S2, the method for obtaining the feeder protection action signal includes: Acquire a contact signal or a level signal representing a protection action from a feeder protection device as a feeder protection action signal; Obtain feeder protection action signals from messages via the communication network; According to the acquired current data of the first branch and the second branch, a feeder protection action signal is calculated and determined to be generated.

8. The method for determining the branch where the overhead line fault is located according to claim 5, characterized in that: The step S3 is specifically as follows: At the moment of feeder protection action, if the current data of the second branch is greater than 0.5 times the current data of the first branch, it is determined that the contact network fault causing the feeder protection action is located in the second branch, otherwise it is not in the second branch.

9. The method for determining the branch where the overhead line fault is located according to claim 5, characterized in that: The step S3 is specifically as follows: The current data of the first branch and the current data of the second branch within a period of time before and after the feeder protection action is used as the basis for judgment, and the similarity of the data curve shapes of the current data of the first branch and the second branch within the time range in the corresponding time series is compared, and it is determined whether the similarity is greater than the set threshold. If so, it is determined that the contact network fault causing the feeder protection action is located in the second branch, otherwise it is not in the second branch.

10. The method for determining the branch where the overhead line fault is located according to claim 9, characterized in that: The calculation formula for the similarity of the data curve shapes of the current data of the first branch and the second branch in the corresponding time series is: Where d is the minimum Euclidean distance between the current data if of the first branch in the corresponding time series and the current data ib of the second branch after translation along the Y axis, which is used to measure the similarity of the two curves. v is the translation of the second branch current ib along the Y axis, v∈[min(if-ib),max(if-ib)], j is the time point, and n is the total length of the time series.

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