A fault location and protection method for distribution network based on 5G communication network

Abstract

The present invention discloses a fault location and protection method for a distribution network based on a 5G communication network. The 5G communication module is used to send SV messages. The optical fiber channel between each terminal device is eliminated, and there is no need to lay communication cables, which can greatly reduce the laying cost. In the case of reconstruction or expansion, there is no need to re-lay the communication cables. The operation and maintenance are convenient, simple and easy to operate, which can greatly reduce the operation and maintenance cost. Moreover, the communication connection can be established between each terminal device according to the communication link establishment rules, which greatly simplifies the multi-terminal differential communication wiring. By setting an IP address for the 5G communication module, once it is determined that a line has a fault, the fault line can be quickly located according to the IP address, thereby improving the efficiency of operation and maintenance. In the present invention, there is no need to configure a separate host. It only requires communication between adjacent terminal devices or terminal devices across branches. The communication distance can be shortened, the power consumption and operation and maintenance costs can be reduced, the failure rate is also reduced, and the stability of the differential protection is improved.

Description

Technical field:

[0001] The present invention relates to the field of power distribution networks, and in particular to a fault location and protection method for a power distribution network based on a 5G communication network. Background technology:

[0002] A distribution network is a power grid that receives electricity from the transmission grid or regional power plants and distributes it locally or in a tiered manner according to voltage to various users through distribution facilities. Composed of overhead lines, cables, towers, distribution transformers, disconnectors, VAR compensators, and other ancillary facilities, the distribution network plays a crucial role in distributing electricity within the power grid. The distribution network is characterized by multiple voltage levels, a complex network structure, diverse equipment types, numerous and widespread operating locations, and a relatively poor safety environment. Consequently, it presents a relatively high number of safety risks. Furthermore, the distribution network's function of providing electricity to a wide range of users places higher demands on its safe and reliable operation. Failure to promptly rectify a distribution network fault and restore power often results in significant economic losses from power outages and production halts.

[0003] However, distribution networks are complex, and with the increasing use of power electronic devices, their fault characteristics have significantly changed. Traditional fault location and isolation methods, which rely on overcurrent or distance sensors, have been significantly challenged. Differential protection, due to its simplicity and reliability, can promptly detect distribution network faults. However, traditional differential protection relies primarily on dedicated fiber-optic lines, requiring fiber channels between all relevant devices. Specifically, for unit-level differential protection, for a two-terminal line, one fiber channel is required between the two devices. For a three-terminal line, one fiber channel is required between each of the three devices, for a total of three fiber channels. For a four-terminal line, the complexity of the system makes traditional fiber-optic data exchange difficult to implement. Wide-area differential protection, on the other hand, requires differential calculations based on cross-element electrical quantity information, and is generally implemented using a master-slave model. Local devices transmit local information to a master, which then constructs the topological differential elements, calculates differential currents, and identifies faults. The master then issues fault isolation commands to each local device, which then isolates the fault. Not only does it have the problem of complex fiber optic wiring, high laying cost, difficult construction, and difficult operation and maintenance, but once the line is rebuilt or expanded, the fiber optic channel needs to be re-laid, the protection configuration is inflexible, and it cannot meet the needs of massive connections in the distribution network, and a host is required for comprehensive judgment.

[0004] Currently, there is also technology that uses wireless communication to send information to the host. However, since all devices in the distribution network need to send information to the host, the communication distance of some devices is bound to be long, resulting in problems such as long communication distance and high power consumption, which increases operation and maintenance costs, high failure rate and poor stability. Summary of the invention:

[0005] In order to solve the above problems, the purpose of the present invention is to provide a fault location and protection method for the distribution network based on the 5G communication network, which can greatly reduce the laying cost, and has convenient, simple, easy operation, low cost, high fault judgment accuracy, and can locate the fault line in time.

[0006] The present invention is implemented by the following technical solutions:

[0007] A method for fault location and protection of a distribution network based on a 5G communication network, comprising the following steps:

[0008] S1. Each terminal device in the distribution network is equipped with a circuit breaker that can disconnect the fault current, and a collection device that can collect current signals is configured at both ends of each terminal device. Each terminal device is also equipped with a 5G communication module.

[0009] S2. Using any terminal device in the distribution network as a node and the distribution network transmission line as a branch, a corresponding topology structure tree is constructed based on the primary wiring diagram of the protected area.

[0010] S3. Set an IP address for the 5G communication module corresponding to each terminal device;

[0011] S4. Start the differential protection mode and perform fault location and protection on the distribution network transmission line by using the differential protection method, which includes the following steps:

[0012] S41. Current data at both ends of the same line is collected by using collection devices at both ends of the line in a synchronous sampling manner, and the collected current data, instantaneous time data during current collection, and IP information of the 5G communication module corresponding to the collection device are collectively used as an SV message;

[0013] S42. According to the communication link establishment rules, the client terminal devices at both ends of the same line send the SV message of the client terminal device to the server terminal device;

[0014] S43. Determine whether a fault occurs in the power transmission line between two adjacent terminal devices according to the unit-level differential protection method based on the SV message received by the server terminal device;

[0015] S44. If it is determined in S43 that the power transmission line between the two terminal devices has failed, the circuit breaker corresponding to the client terminal device is disconnected, and based on the IP information in the SV message received by the server terminal device, it can be determined which client terminal device and server terminal device has failed in the power transmission line;

[0016] At the same time, a wide-area differential protection method is used to determine whether a fault has occurred on the transmission line between the terminal equipment across the branch;

[0017] S45. If it is determined in S44 that a fault occurs in the power transmission line between the cross-branch terminal devices, the circuit breaker corresponding to the client terminal device corresponding to the faulty line is cut off, and based on the IP information in the SV message received by the server terminal device, it can be known which client terminal device has a power transmission line close to the server terminal device that has a fault.

[0018] Furthermore, the collection device is a merging unit.

[0019] Furthermore, in S2, when constructing the topology tree, any terminal device is used as a root node, and adjacent terminal devices are used as child nodes.

[0020] Furthermore, in said S41, the current data is collected using a synchronous sampling method based on a GPS clock signal;

[0021] If the instantaneous time of current collection in the SV message received by the server terminal device is inconsistent with the instantaneous time of current collection in the SV message of the server terminal device itself, it is determined that the GPS clock signal is abnormal, and the synchronous sampling method based on the GPS clock signal is switched to the constant temperature crystal oscillator to synchronize the current data.

[0022] If, after 10 minutes of synchronous collection of current data using a constant temperature crystal oscillator, the instantaneous time of current collection in the SV message received by the server terminal device is still inconsistent with the instantaneous time of current collection in the SV message of the server terminal device itself, the server terminal device and the client terminal device that are not sampling synchronously will exit the differential protection mode, and the synchronization method of the constant temperature crystal oscillator timekeeping will be switched to a synchronous sampling method based on the voltage vector.

[0023] Furthermore, in said S42, when the communication link is established, the terminal device at the upper level in the topology structure tree is used as the server when the communication link is established, and the terminal device at the lower level in the topology structure tree is used as the client when the communication link is established.

[0024] Furthermore, in S43, the specific method of unit-level differential protection is:

[0025] First, the client terminal devices at both ends of the same line send their corresponding SV message data to the server terminal device through their own 5G communication modules;

[0026] Secondly, the server terminal device calculates the differential current between the current data in the received SV message data and the current data in its own SV message data;

[0027] If the differential current is 0, it is determined that the power transmission line connecting the client terminal device and the server terminal device is normal;

[0028] If the differential current is not zero, it is determined that a power transmission line connecting the client terminal device and the server terminal device has a fault.

[0029] Furthermore, in S44, the specific method of wide-area differential protection is:

[0030] First, the next-level terminal device corresponding to the client terminal device of the faulty line in the topology structure tree is used as the new client terminal device, and its corresponding SV message data is sent to the server terminal device corresponding to the faulty line through its own 5G communication module;

[0031] Secondly, the server terminal device calculates the differential current between the current data in the received SV message data and the current data in its own SV message data;

[0032] If the differential current is 0, it is determined that the power transmission line between the new client terminal device and the client terminal device corresponding to the fault line is normal, that is, the power transmission line on the side of the new client terminal device close to the server terminal device is normal;

[0033] If the differential current is not 0, it is determined that the power transmission line connecting the new client terminal device and the client terminal device corresponding to the faulty line is faulty, that is, the power transmission line on the side of the new client terminal device close to the server terminal device is faulty.

[0034] Advantages of the present invention:

[0035] By configuring a 5G communication module and using it to send SV messages, the optical fiber channel between each terminal device is eliminated, and there is no need to lay communication cables, which can greatly reduce the laying cost. For reconstruction and expansion, there is no need to re-lay communication cables. The operation and maintenance are convenient and easy to operate, which can greatly reduce the operation and maintenance cost. Moreover, the communication connection can be established between each terminal device according to the communication link establishment rules, which greatly simplifies the multi-terminal differential communication wiring.

[0036] By setting an IP address for the 5G communication module, once a line fault is determined, the IP information in the SV message received by the server terminal device can be used to determine which client server the received SV message corresponds to, and then determine which client terminal device has a power transmission line fault close to the server terminal device. Ultimately, the faulty line can be quickly located, improving the efficiency of operation and maintenance.

[0037] The present invention mainly collects current data by synchronizing the GPS clock signal. When the GPS synchronization signal becomes abnormal, it is promptly replaced with a constant temperature crystal oscillator to synchronize the current data. If, after a certain period of time, the instantaneous time of current collection in the SV message received by the server terminal device is still inconsistent with the instantaneous time of current collection in the SV message of the server terminal device itself, the differential protection mode is exited, and the synchronization method of the constant temperature crystal oscillator is switched to a synchronous sampling method based on the voltage vector. In this way, the accuracy of the differential current can be ensured by multiple synchronization methods, thereby improving the accuracy of fault judgment. At the same time, if the current collection time of the two terminal devices at both ends of the transmission line cannot be synchronized for a long time, the terminal device that cannot be sampled synchronously will be promptly exited from the differential protection to avoid malfunction of the circuit breaker.

[0038] In addition, by establishing corresponding communication link establishment rules, no matter whether the unit-level differential protection method or the wide-area differential protection method is adopted, the present invention does not need to configure a separate host. It only requires communication between adjacent terminal devices or terminal devices across branches, which can shorten the communication distance, reduce power consumption and operation and maintenance costs, and at the same time, reduce the failure rate and improve the stability of differential protection. Description of the drawings:

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 The 9-node overhead line in Example 2;

[0041] Figure 2 This is a topology structure tree constructed in Example 2 with the terminal device 103 as the root node. Specific implementation method:

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] Example 1:

[0044] A method for fault location and protection of a distribution network based on a 5G communication network, comprising the following steps:

[0045] S1. A circuit breaker capable of disconnecting fault current is configured for each terminal device in the distribution network, and a collection device capable of collecting current signals is configured at both ends of each terminal device, and each terminal device is configured with a 5G communication module; the collection device is a merging unit.

[0046] S2. Using any terminal device in the distribution network as a node and the distribution network transmission line as a branch, a topology structure tree is constructed based on the primary wiring diagram of the protected area, with any terminal device as the root node and adjacent terminal devices as child nodes.

[0047] S3. Set an IP address for the 5G communication module corresponding to each terminal device;

[0048] S4. Start the differential protection mode and perform fault location and protection on the distribution network transmission line by using the differential protection method, which includes the following steps:

[0049] S41. Current data at both ends of the same line is collected by using collection devices at both ends of the line in a synchronous sampling manner, and the collected current data, instantaneous time data during current collection, and IP information of the 5G communication module corresponding to the collection device are collectively used as an SV message;

[0050] In this embodiment, a synchronous sampling method based on GPS clock signal is used to collect current data;

[0051] If the instantaneous time of current collection in the SV message received by the server terminal device is inconsistent with the instantaneous time of current collection in the SV message of the server terminal device itself, it is determined that the GPS clock signal is abnormal, and the synchronous sampling method based on the GPS clock signal is switched to the constant temperature crystal oscillator to synchronize the current data.

[0052] If, after 10 minutes of synchronous collection of current data using a constant temperature crystal oscillator, the instantaneous time of current collection in the SV message received by the server terminal device is still inconsistent with the instantaneous time of current collection in the SV message of the server terminal device itself, the server terminal device and the client terminal device that are not sampling synchronously will exit the differential protection mode, and the synchronization method of the constant temperature crystal oscillator timekeeping will be switched to a synchronous sampling method based on the voltage vector.

[0053] In this embodiment, since only the two asynchronous sampling devices are exited from the differential protection mode, other terminal devices in the distribution network are not affected and remain in the differential protection mode, the overall differential protection of the distribution network is not affected.

[0054] S42. According to the communication link establishment rules, the client terminal devices at both ends of the same line send the SV message of the client terminal device to the server terminal device;

[0055] When a communication link is established, the terminal device at the upper level in the topology structure tree is used as the server when the communication link is established, and the terminal device at the lower level of the server in the topology structure tree is used as the client when the communication link is established.

[0056] S43. Determine whether a fault occurs in the power transmission line between two adjacent terminal devices according to the unit-level differential protection method based on the SV message received by the server terminal device;

[0057] The specific method of unit-level differential protection is:

[0058] First, the client terminal devices at both ends of the same line send their corresponding SV message data to the server terminal device through their own 5G communication modules;

[0059] Secondly, the server terminal device calculates the differential current between the current data in the received SV message data and the current data in its own SV message data;

[0060] If the differential current is 0, it is determined that the power transmission line connecting the client terminal device and the server terminal device is normal;

[0061] If the differential current is not zero, it is determined that a power transmission line connecting the client terminal device and the server terminal device has a fault.

[0062] S44. If it is determined in S43 that the power transmission line between the two terminal devices has failed, the circuit breaker corresponding to the client terminal device is disconnected, and based on the IP information in the SV message received by the server terminal device, it can be determined which client terminal device and server terminal device has failed in the power transmission line;

[0063] At the same time, a wide-area differential protection method is used to determine whether a fault has occurred on the transmission line between the terminal equipment across the branch;

[0064] The specific method of wide-area differential protection is:

[0065] First, the next-level terminal device corresponding to the client terminal device of the faulty line in the topology structure tree is used as the new client terminal device, and its corresponding SV message data is sent to the server terminal device corresponding to the faulty line through its own 5G communication module;

[0066] Secondly, the server terminal device calculates the differential current between the current data in the received SV message data and the current data in its own SV message data;

[0067] If the differential current is 0, it is determined that the power transmission line between the new client terminal device and the client terminal device corresponding to the fault line is normal, that is, the power transmission line on the side of the new client terminal device close to the server terminal device is normal;

[0068] If the differential current is not 0, it is determined that the power transmission line connecting the new client terminal device and the client terminal device corresponding to the faulty line is faulty, that is, the power transmission line on the side of the new client terminal device close to the server terminal device is faulty.

[0069] S45. If it is determined in S44 that a fault occurs in the power transmission line between the cross-branch terminal devices, the circuit breaker corresponding to the client terminal device corresponding to the faulty line is cut off, and based on the IP information in the SV message received by the server terminal device, it can be known which client terminal device has a power transmission line close to the server terminal device that has a fault.

[0070] Example 2:

[0071] like Figure 1 The overhead line has 9 nodes, i.e., it includes 9 terminal devices, of which 101 to 109 are 9 terminal devices and 201 to 207 are main supply lines. According to the method of Example 1, the overhead line is fault-located and protected based on the distribution network of the 5G communication network, including the following steps:

[0072] S1. A merging unit is configured at both ends of each terminal device, and each terminal device is configured with a 5G communication module, and each terminal device is configured with a circuit breaker. In this embodiment, for the convenience of description, the number of each terminal device is consistent with the number of the circuit breaker.

[0073] S2, taking the terminal device 103 as the root node as an example, the topology structure tree constructed is as follows Figure 2 shown.

[0074] S3. Set an IP address for the 5G communication module corresponding to each terminal device;

[0075] S4. The merging unit collects current data from both ends of the same line in a GPS synchronization manner, and uses the collected current data, instantaneous time data when the current is collected, and IP information as an SV message;

[0076] S5, such as Figure 2In the example, when the terminal device 103 establishes a communication link with the terminal devices 102 and 104, the terminal device 103 acts as a server terminal device, and the terminal devices 102 and 104 act as client terminal devices;

[0077] When terminal device 103 establishes a link with terminal device 102, terminal device 102, as a client terminal device, initiates a communication link establishment request and actively sends the SV message corresponding to terminal device 102 to terminal device 103, as a server terminal device. This communication link is mainly used for differential protection of line 202.

[0078] S6. In this embodiment, a unit-level differential protection link is established between the terminal device 103 and the terminal device 102, and between the terminal device 103 and the terminal device 104 according to the unit-level differential protection method.

[0079] The terminal device 103 calculates the differential current between the current data in the SV message data received from the terminal device 102 and the current data in the SV message data of the terminal device 103 itself;

[0080] If the differential current is 0, it is determined that line 202 is normal;

[0081] If the differential current is not zero, it is determined that a fault occurs in line 202 .

[0082] S7. If a fault occurs in line 202, the circuit breaker 102 corresponding to the terminal device 102 is disconnected, and a wide-area differential protection method is used to determine whether a fault occurs in line 201 between the terminal device 102 and the next-level terminal device 101. The specific method is as follows:

[0083] The terminal device 101 actively sends the SV message corresponding to the terminal device 101 to the terminal device 103. The terminal device 103 calculates the differential current between the current data in the SV message data received from the terminal device 101 and the current data in the SV message data of the terminal device 103 itself.

[0084] If the differential current is 0, it is determined that line 201 is normal;

[0085] If the differential current is not 0, it is determined that a fault occurs in line 201 .

[0086] S8. If a fault occurs in the line 201, the circuit breaker 101 corresponding to the terminal device 101 is disconnected to protect the distribution network.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for fault location and protection of a distribution network based on a 5G communication network, characterized in that: The following steps are involved: S1. Each terminal device in the distribution network is equipped with a circuit breaker that can disconnect the fault current, and a collection device that can collect current signals is configured at both ends of each terminal device. Each terminal device is also equipped with a 5G communication module. S2. Using any terminal device in the distribution network as a node and the distribution network transmission line as a branch, a corresponding topology structure tree is constructed based on the primary wiring diagram of the protected area. S3. Set an IP address for the 5G communication module corresponding to each terminal device; S4. Start the differential protection mode and perform fault location and protection on the distribution network transmission line by using the differential protection method, which includes the following steps: S41. Current data at both ends of the same line is collected by using collection devices at both ends of the line in a synchronous sampling manner, and the collected current data, instantaneous time data during current collection, and IP information of the 5G communication module corresponding to the collection device are collectively used as an SV message; S42. According to the communication link establishment rules, the client terminal devices at both ends of the same line send the SV message of the client terminal device to the server terminal device; S43. Determine whether a fault occurs in the power transmission line between two adjacent terminal devices according to the unit-level differential protection method based on the SV message received by the server terminal device; S44. If it is determined in S43 that the power transmission line between the two terminal devices is faulty, the circuit breaker corresponding to the client terminal device is disconnected, and the power transmission line between which client terminal device and the server terminal device is faulty is determined based on the IP information in the SV message received by the server terminal device. At the same time, a wide-area differential protection method is used to determine whether a fault has occurred on the transmission line between the terminal equipment across the branch; S45. If it is determined in S44 that a transmission line between the inter-branch terminal devices has a fault, the circuit breaker corresponding to the client terminal device corresponding to the faulty line is disconnected, and based on the IP information in the SV message received by the server terminal device, it is determined which client terminal device has a transmission line fault close to the server terminal device. In the S41, current data is collected using a synchronous sampling method based on a GPS clock signal; If the instantaneous time of current collection in the SV message received by the server terminal device is inconsistent with the instantaneous time of current collection in the SV message of the server terminal device itself, it is determined that the GPS clock signal is abnormal, and the synchronous sampling method based on the GPS clock signal is switched to the constant temperature crystal oscillator to synchronize the current data. If, after 10 minutes of synchronous sampling of current data using the constant temperature crystal oscillator (OCO) timing, the instantaneous time of current sampling in the SV message received by the server terminal device is still inconsistent with the instantaneous time of current sampling in the SV message of the server terminal device itself, the server terminal device and the client terminal device that are not synchronously sampling will be exited from the differential protection mode, and the synchronization method of the constant temperature crystal oscillator (OCO) timing will be switched to the synchronous sampling method based on the voltage vector; In said S42, when the communication link is established, the terminal device at the upper level in the topology structure tree is used as the server when the communication link is established, and the terminal device at the lower level in the topology structure tree is used as the client when the communication link is established.

2. A method for fault location and protection of a distribution network based on a 5G communication network according to claim 1, characterized in that: The collecting device is a merging unit.

3. A method for fault location and protection of a distribution network based on a 5G communication network according to claim 1, characterized in that: In S2, when constructing the topology tree, any terminal device is used as a root node, and adjacent terminal devices are used as child nodes.

4. A method for fault location and protection of a distribution network based on a 5G communication network according to claim 1, characterized in that: In S43, the specific method of unit-level differential protection is: First, the client terminal devices at both ends of the same line send their corresponding SV message data to the server terminal device through their own 5G communication modules; Secondly, the server terminal device calculates the differential current between the current data in the received SV message data and the current data in its own SV message data; If the differential current is 0, it is determined that the power transmission line connecting the client terminal device and the server terminal device is normal; If the differential current is not zero, it is determined that a power transmission line connecting the client terminal device and the server terminal device has a fault.

5. The method for fault location and protection of a distribution network based on a 5G communication network according to claim 1, characterized in that: In S44, the specific method of wide-area differential protection is: First, the next-level terminal device corresponding to the client terminal device of the faulty line in the topology structure tree is used as the new client terminal device, and its corresponding SV message data is sent to the server terminal device corresponding to the faulty line through its own 5G communication module; Secondly, the server terminal device calculates the differential current between the current data in the received SV message data and the current data in its own SV message data; If the differential current is 0, it is determined that the power transmission line between the new client terminal device and the client terminal device corresponding to the fault line is normal, that is, the power transmission line on the side of the new client terminal device close to the server terminal device is normal; If the differential current is not 0, it is determined that the power transmission line connecting the new client terminal device and the client terminal device corresponding to the faulty line is faulty, that is, the power transmission line on the side of the new client terminal device close to the server terminal device is faulty.

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