A data transmission method of a dynamic response 5G communication differential protection

Abstract

The application discloses a kind of dynamic response 5G communication differential protection data transmission method, so that the differential protection service based on 5G communication is widely applied in low-voltage distribution network field, promote the development of new technology of power grid relay protection, solve the protection terminal of traditional low-voltage power grid not dependent on channel cannot give consideration to speed and selectivity requirement, by using advanced 5G communication technology, with the high bandwidth of 5G communication network, low latency and high reliability wireless communication environment, realize the large-scale application of longitudinal differential protection in closed-loop operation low-voltage power grid, improve the protection level of power grid.The application applies dynamic response transmission mode in the communication process of distribution network transmission line differential protection based on 5G communication, meets the rapidity requirement of relay protection, reduces 5G communication transmission flow, saves communication resources and reduces communication cost.

Description

Technical Field

[0001] This invention relates to a data transmission method for dynamic response 5G communication differential protection, belonging to the field of power system relay protection technology. Background Technology

[0002] The high proportion of distributed power sources connected to the distribution network has changed the original distribution characteristics of the network power sources. It is difficult to achieve rapid and accurate identification of fault sections by relying solely on the simple overcurrent protection principle. It is necessary to adopt a multi-point information comparison method with absolute selectivity. The longitudinal differential protection makes full use of the communication channel to expand the information collection range. It has the advantages of sensitivity, reliability, and fast action speed, and can adapt to various complex fault operating conditions, effectively improving the level of power grid protection.

[0003] The first problem to be solved in line differential protection is data synchronization and fast communication. Dedicated optical fiber can meet the fast communication requirements of longitudinal protection, but it requires large-scale fiber optic deployment, which is difficult to carry out and has high investment. In addition, some power distribution terminals are not equipped with the conditions for fiber optic deployment, which is not conducive to the promotion and application of differential protection in the distribution network.

[0004] Line differential protection uses a channel to transmit electrical quantities such as voltage and current, as well as switching signals, from one side to the other. Each side's protection device distinguishes between faults within and outside its zone based on the comparison of data from both sides. Existing 5G-based line differential protection typically adopts a real-time communication mode, borrowing from the traditional fiber optic differential protection data transmission model. This means that the protection devices on both sides of the line send the data collected on their respective sides to the device on the other side at a frequency of 1.2kHz for real-time logic calculation and discrimination. Calculations show that real-time communication devices will generate up to 500GB of data traffic per month, resulting in high traffic overhead, high communication costs, and poor economic efficiency, making it unsuitable for widespread application.

[0005] Therefore, the high data traffic overhead and high communication cost of 5G in existing line differential protection data transmission are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0006] Objective: To overcome the shortcomings of existing technologies, this invention provides a data transmission method for dynamic response 5G communication differential protection, which reduces 5G communication data transmission traffic and communication costs while meeting the speed requirements of relay protection, effectively improving the economic efficiency of 5G communication line differential protection.

[0007] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A data transmission method for dynamic response differential protection in 5G communication includes the following steps:

[0009] When the distribution network line is working normally, the 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line use a non-real-time communication mode to transmit data, which is used to maintain the normal link establishment of the channel and the corresponding data required for the detection logic during the normal operation of the differential protection.

[0010] When a system disturbance or fault occurs in the distribution network line, the 5G differential protection device on the strong power supply M side is activated. The 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line switch to real-time communication mode to transmit data, and set the differential enable signal DifStart and the communication mode ComMode flag.

[0011] When a system disturbance or fault occurs in the distribution network line, and the starting element of the 5G differential protection device on the N side of the weak power source fails to operate, if the 5G differential protection device on the N side of the weak power source receives the differential allow signal DifStart flag bit from the 5G differential protection device on the other side, it will immediately switch to real-time communication mode to transmit data and set the ComMode flag bit.

[0012] As a preferred embodiment, the following is also included: when a system disturbance or fault occurs in the distribution network line, the 5G differential protection device on the strong power supply M side is activated, and the 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line switch to real-time communication mode to transmit data, and set the differential enable signal DifStart and the communication mode ComMode flags; when the protection activation element returns, the 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line switch to non-real-time communication mode to transmit data, and deactivate the DifStart and ComMode flags.

[0013] As a preferred embodiment, the following further includes: when a system disturbance or fault occurs in the distribution network line, and the starting element of the 5G differential protection device on the N side of the weak power source fails to operate, if the 5G differential protection device on the N side of the weak power source receives the differential enable signal DifStart flag bit from the 5G differential protection device on the other side, it immediately switches to real-time communication mode to transmit data and sets the ComMode flag bit; when the 5G differential protection device on the N side of the weak power source receives the DifStart flag bit from the protection number on the other side, the 5G differential protection on the N side of the weak power source switches to non-real-time communication mode to transmit data and removes the ComMode flag bit.

[0014] As a preferred embodiment, the non-real-time communication mode means that the 5G differential protection device sends sampling point data S to the other side every second. w The corresponding UDP packet frames are sent in T UDP packets per second.

[0015]

[0016] Where T is a natural number and f is the number of sampling points per second.

[0017] The UDP packet frame includes: UDP header data, SV packet data, and UDP trailer data. The UDP header data includes the MAC header, IP header, length / type, and UDP header. The UDP trailer data includes century seconds, century nanoseconds, and CRC code. The SV packet data includes the destination address, source address, packet type, application identifier (APPID), packet length, reserved bits, and application protocol data unit (APDU).

[0018] As a preferred option, the application protocol data unit includes SV configuration and sampling point data S. w w represents the w-th sampling point data per second, and each sampling point data includes the fundamental cosine amplitude A of the three-phase current. c1 Three-phase current fundamental sinusoidal amplitude A s1 Synchronization flag (Syn), sampling sequence number (SamCnt), differential activation flag (Ena), three-phase differential enable flag (DifStart), communication mode (ComMode), switch position (TWJ), and checksum (SumCRC).

[0019] As a preferred option, the value of T ranges from 1 to 10.

[0020] As a preferred embodiment, the real-time communication mode means that the 5G differential protection device sends UDP packet frames encapsulated with the current sampling point data to the opposite 5G differential protection device at a rate of f points per second.

[0021] As the preferred option, f = 1200.

[0022] As a preferred option, the protection activation criteria for the 5G differential protection device are as follows:

[0023] Power frequency change current starting element. The power frequency change current starting element will activate and extend for 7 seconds when the following operating equation is satisfied;

[0024] ΔI ΦΦMAX >1.25ΔI T +ΔI set

[0025] Where, ΔI ΦΦMAX The maximum value among the half-wave integrals of the three phase-to-phase current RMS values; ΔI set A fixed threshold that can be adjusted; ΔI T It is a floating threshold that automatically adjusts as the amount of change changes.

[0026] Zero-sequence current starting element. When the self-generated zero-sequence current exceeds the zero-sequence current starting setting value, the zero-sequence current starting element activates and extends for 7 seconds;

[0027] Negative sequence current starting element. When the negative sequence current exceeds the negative sequence current starting setting value, the negative sequence current starting element activates and extends for 7 seconds;

[0028] Low-voltage differential current starting element. When the protection device receives a differential protection permission signal from the opposite side, and the phase or phase-to-phase voltage related to the operation of the differential element is less than 65% of the rated voltage, the low-voltage differential current starting element operates and is delayed for 7 seconds;

[0029] If any of the above starting elements activates, the 5G differential protection device is determined to be activated.

[0030] Beneficial Effects: The data transmission method for dynamic response 5G communication differential protection provided by this invention enables the widespread application of 5G communication-based differential protection services in medium and low voltage distribution networks, promotes the development of new technologies for power grid relay protection, and solves the problem that traditional medium and low voltage power grid protection terminals that do not rely on channels cannot simultaneously meet the requirements of speed and selectivity. By adopting advanced 5G communication technology and leveraging the high bandwidth, low latency, and high reliability of the 5G communication network's wireless communication environment, the invention enables the large-scale application of longitudinal differential protection in closed-loop medium and low voltage power grids, thereby improving the protection level of the power grid.

[0031] This invention applies a dynamic response transmission mode in the differential protection communication process of power distribution transmission lines based on 5G communication, which meets the requirements of relay protection speed, while reducing 5G communication transmission traffic, saving communication resources, and reducing communication costs. Attached Figure Description

[0032] Figure 1 This is a flowchart of a dynamic response 5G differential protection data transmission process.

[0033] Figure 2 This is a diagram of a dynamic response 5G differential protection data transmission architecture.

[0034] Figure 3 A 5G differential protection data transmission frame structure for dynamic response.

[0035] Figure 4 This is a schematic diagram of 5G differential protection data transmission with dynamic response. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] like Figure 1 As shown, a data transmission method for dynamic response differential protection in 5G communication includes the following steps:

[0038] Step S1, as follows Figure 2 As shown, 5G differential protection devices are installed on both sides of the medium- and low-voltage distribution network lines M and N, respectively, and connected to a clock source to achieve time synchronization. Each 5G differential protection device simultaneously collects the instantaneous values ​​of the three-phase voltage, the instantaneous values ​​of the three-phase current, clock information, and switch position information at a frequency of 1.2kHz on the rising edge of the clock second pulse.

[0039] Step S2, as follows Figure 3 As shown, each side of the 5G differential protection device generates 1200 UDP packet frames per second for 5G communication data transmission;

[0040] A UDP packet frame consists of UDP header data, SV data, and UDP trailer data. The UDP header data includes the MAC header, IP header, length / type, and UDP header, while the UDP trailer data includes century seconds, century nanoseconds, and CRC code.

[0041] SV message data includes destination address, source address, message type, application identifier (APPID), message length, reserved bits, and application protocol data unit (APDU).

[0042] APDU includes SV configuration and sampling point data S w (1≤w≤1200).

[0043] Each sampling point data includes the fundamental cosine amplitude A of the three-phase current. c1 Three-phase current fundamental sinusoidal amplitude A s1 Synchronization flag (Syn), sampling sequence number (SamCnt), differential activation flag (Ena), three-phase differential enable flag (DifStart), communication mode (ComMode), switch position (TWJ), and checksum (SumCRC).

[0044] in,

[0045]

[0046]

[0047] In the above formula, x k is the instantaneous current value at the sampling point, and N is the number of sampling points per cycle, which is 24.

[0048] In step S3, during the initial stage of data transmission, the 5G differential protection devices on the M and N sides use a non-real-time communication mode to transmit data in order to maintain the normal link establishment of the channel and the corresponding data required for the detection logic during the normal operation of the differential protection.

[0049] The aforementioned non-real-time communication mode refers to each 5G differential protection device sending sampling point data S to the other side every second. w The corresponding UDP packet frames are sent in T UDP packets per second.

[0050]

[0051] Wherein, the number of transmission points per second (T) is a fixed value, ranging from 1 to 10. The value of T will affect the channel delay between the two-sided 5G differential protection depending on the current 5G network environment; generally, the smaller the T value, the greater the channel delay. To significantly reduce data transmission traffic, the T value should be set to the minimum while ensuring the channel delay is less than 20ms. For example, if f is 1200, T is 5, and t is a natural number from 1 to 5, the calculated w will be 240, 480, 720, 960, and 1200 respectively, i.e., S... 240 S 480 S 720 S 960 S 1200 Data from 5 sampling points within 1 second.

[0052] Step S4: When a system disturbance or fault occurs in the low-voltage distribution network line, the 5G differential protection device on the M side of the high-voltage power supply side is activated. The protection activation criteria are composed of the following components:

[0053] 1) Power frequency variation current starting element. The power frequency variation current starting element will activate and extend for 7 seconds when the following operating equation is satisfied;

[0054] ΔI ΦΦMAX >1.25ΔI T +ΔI set (4)

[0055] Where, ΔI ΦΦMAX The maximum value among the half-wave integrals of the three phase-to-phase current RMS values; ΔI se t is a fixed threshold that can be adjusted; ΔI T It is a floating threshold that automatically adjusts as the amount of change changes.

[0056] 2) Zero-sequence current starting element. When the self-generated zero-sequence current exceeds the zero-sequence current starting setting value, the zero-sequence current starting element activates and extends for 7 seconds;

[0057] 3) Negative sequence current starting element. When the negative sequence current exceeds the negative sequence current starting setting value, the negative sequence current starting element will activate and extend for 7 seconds;

[0058] 4) Low-voltage differential current starting element. When the protection device receives a differential protection permission signal from the opposite side, and the phase or phase-to-phase voltage related to the operation of the differential element is less than 65% of the rated voltage, the low-voltage differential current starting element operates and is delayed for 7 seconds;

[0059] Step S5, as follows Figure 4 As shown, when any of the above protection starting elements are activated, the 5G differential protection switches to real-time communication mode to transmit data and sets the differential enable signal DifStart and the communication mode ComMode flag. After the protection starting element returns, the 5G differential protection switches to non-real-time communication mode to transmit data and removes the DifStart and ComMode flags.

[0060] The real-time communication mode refers to the 5G differential protection sending UDP packet frames encapsulated at the current sampling point to the other device at 1200 points per second in real time so that the other device can perform differential protection logic calculations.

[0061] Step S6: When the N-side protection starting element of the weak power supply side fails to operate due to disturbance or fault in the medium and low voltage line system, if the N-side 5G differential protection device receives the DifStart flag of the differential protection on the opposite side, it immediately switches to real-time communication mode and sets the ComMode flag; after receiving the DifStart flag from the opposite side, the N-side 5G differential protection switches to non-real-time communication mode to transmit data and exits the ComMode flag.

[0062] In step S7, after each side's 5G differential protection device receives the ComMode flag bit from the other side, it processes the data from the other side's 5G differential protection device and makes a trip output decision based on the differential protection logic calculation results.

[0063] In the absence of the data transmission method for 5G communication differential protection with dynamic response as described in this invention, the protection device adopts a real-time data transmission mode, with each message frame length being 190 bytes. The real-time communication message transmission frequency of the protection device is 1200Hz, and the monthly uplink traffic consumption is...

[0064] 190Byte*1200*3600s*24h*30d≈550GB

[0065] When using the dynamic response 5G communication differential protection data transmission method of this invention, since it switches to real-time transmission mode when the system experiences disturbances, the protection speed is consistent with the current 5G differential protection. In non-real-time transmission mode, when the number of transmission points per second T is 1, the monthly uplink traffic consumption is:

[0066] 190Byte*3600s*24h*30d≈0.459GB

[0067] When the number of transmissions per second (T) is 10, the monthly uplink traffic consumption is:

[0068] 190Byte*10*3600s*24h*30d≈4.59GB

[0069] Therefore, it can be seen that the 5G differential protection of the present invention can reduce the data transmission traffic to 1% of the original while meeting the requirements of relay protection speed, which greatly reduces the 5G communication transmission traffic, saves communication resources, and reduces communication costs.

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A data transmission method for dynamic response differential protection in 5G communication, characterized in that: Includes the following steps: When the distribution network line is working normally, the 5G differential protection device on the strong power supply M side and the weak power supply N side of the distribution network line uses a non-real-time communication mode to transmit data, which is used to maintain the normal link establishment of the channel and the corresponding data required for the detection logic during the normal operation of the differential protection. When a system disturbance or fault occurs in the distribution network line, the 5G differential protection device on the strong power supply M side is activated. The 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line switch to real-time communication mode to transmit data, and set the differential enable signal DifStart and the communication mode ComMode flag. When a system disturbance or fault occurs in the distribution network line, and the starting element of the 5G differential protection device on the N side of the weak power source fails to operate, if the 5G differential protection device on the N side of the weak power source receives the differential allow signal DifStart flag bit from the 5G differential protection device on the other side, it will immediately switch to real-time communication mode to transmit data and set the communication mode ComMode flag bit. The non-real-time communication mode means that the 5G differential protection device sends sampling point data S to the other side every second. w The corresponding UDP packet frames, a total of T UDP packet frames are sent per second; Where T is a natural number, and f is the number of sampling points per second; The UDP packet frame includes: UDP packet header data, SV packet data, and UDP packet trailer data; the UDP packet header data includes MAC header, IP header, length / type, and UDP header; the UDP packet trailer data includes century seconds, century nanoseconds, and CRC code; the SV packet data includes destination address, source address, packet type, application identifier (APPID), packet length, reserved bits, and application protocol data unit (APDU).

2. The data transmission method for dynamic response differential protection of 5G communication according to claim 1, characterized in that: Also includes: When a system disturbance or fault occurs in the distribution network line, the 5G differential protection device on the strong power supply M side is activated. The 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line switch to real-time communication mode to transmit data, and set the differential enable signal DifStart and the communication mode ComMode flag. When the protection activation element returns, the 5G differential protection devices on the strong power supply M side and the weak power supply N side of the distribution network line switch to non-real-time communication mode to transmit data, and deactivate the DifStart and ComMode flags.

3. The data transmission method for dynamic response differential protection of 5G communication according to claim 1, characterized in that: Also includes: When a system disturbance or fault occurs in the distribution network line, and the starting element of the 5G differential protection device on the N side of the weak power source fails to operate, if the 5G differential protection device on the N side of the weak power source receives the differential enable signal DifStart flag from the 5G differential protection device on the other side, it immediately switches to real-time communication mode to transmit data and sets the communication mode ComMode flag. When the 5G differential protection device on the N side of the weak power source receives the DifStart flag from the protection number on the other side, the 5G differential protection on the N side of the weak power source switches to non-real-time communication mode to transmit data and removes the ComMode flag.

4. The data transmission method for dynamic response differential protection of 5G communication according to claim 1, characterized in that: The application protocol data unit includes SV configuration and sampling point data S. w w represents the w-th sampling point data per second, and each sampling point data includes the fundamental cosine amplitude A of the three-phase current. c1 Three-phase current fundamental sinusoidal amplitude A s1 Synchronization flag (Syn), sampling sequence number (SamCnt), differential activation flag (Ena), differential enable flag (DifStart), communication mode (ComMode), switch position (TWJ), and checksum (SumCRC).

5. The data transmission method for dynamic response differential protection of 5G communication according to claim 1, characterized in that: The value of T ranges from 1 to 10.

6. A data transmission method for dynamic response differential protection of 5G communication according to any one of claims 1-3, characterized in that: The real-time communication mode means that the 5G differential protection device sends UDP packet frames encapsulated with the current sampling point data to the opposite 5G differential protection device at a rate of f points per second.

7. The data transmission method for dynamic response differential protection of 5G communication according to claim 6, characterized in that: f＝1200。 8. A data transmission method for dynamic response differential protection of 5G communication according to any one of claims 1-3, characterized in that: The protection activation criteria for the 5G differential protection device are as follows: Power frequency change current starting element; the power frequency change current starting element operates and widens in nanoseconds when the following operating equation is satisfied; ΔI ΦΦMAX >1.25ΔI T +ΔI set Where, ΔI ΦΦMAX The maximum value among the half-wave integrals of the three phase-to-phase current RMS values; ΔI set A fixed threshold that can be adjusted; ΔI T It is a floating threshold that automatically adjusts as the amount of change changes. Zero-sequence current starting element; when the self-generated zero-sequence current is greater than the zero-sequence current starting setting value, the zero-sequence current starting element operates and widens by ns; Negative sequence current starting element; when the negative sequence current is greater than the negative sequence current starting setting value, the negative sequence current starting element operates and widens by ns; Low-voltage differential current starting element; when the protection device receives a differential protection permission signal from the opposite side, and the phase or phase-to-phase voltage related to the operation of the differential element is less than 65% of the rated voltage, the low-voltage differential current starting element operates and is delayed for ns. If any of the above starting elements activates, the 5G differential protection device is determined to be activated.

9. The data transmission method for dynamic response differential protection of 5G communication according to claim 8, characterized in that: n＝7。

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