Method and system for realizing remote trip and remote transmission functions of line multi-terminal current differential protection

Abstract

The application discloses a method and system for realizing the remote tripping and remote transmission functions of multi-terminal line current differential protection, which comprises the following steps: selecting a power supply side line protection device of a multi-terminal line as a master, and selecting the rest of the line protection devices as slaves; adjusting the transmission path of the remote tripping signal or the remote transmission signal by using multi-direction information transmission logic according to whether the master and the slaves have the remote tripping signal or the remote transmission signal input; the line protection device receiving the remote tripping signal acts the output according to the receiving logic and the corresponding local criterion, and trips the circuit breaker on the line side of the line protection device; and the line protection device receiving the remote transmission signal drives the corresponding remote transmission signal output for the opposite side line protection logic. The application solves the problem of complex remote tripping and remote transmission signal information interaction among multi-terminal current differential protection devices, and the problem of easy misoperation and misdriven output; the stability of the multi-terminal system operation is improved, and the application meets the occasions of different line terminal numbers from two terminals to multi terminals.

Description

Technical Field

[0001] This invention belongs to the field of power system technology, specifically relating to a method and system for implementing remote tripping and remote transmission functions of multi-terminal current differential protection for power lines. Background Technology

[0002] Currently, efforts are being accelerated to build a new power system based on new energy sources. However, most areas rich in wind and solar power resources are far from load centers and require long-distance transmission to connect to the regional power grid. Considering factors such as saving on equipment investment and reducing land acquisition, multi-terminal current differential protection is increasingly appearing in high-voltage transmission lines. When a line fault occurs between a circuit breaker and the line protection current transformer, the fault is within the busbar protection's operating zone, and the busbar protection trips the circuit breaker on its side. Alternatively, when the line failure protection activates remote tripping of all circuit breakers on the opposite side of the busbar containing the failed line, the remote tripping function of the line protection is required to trip the circuit breakers on the opposite side.

[0003] The existing technology, "A Fiber Optic Differential Protection Method for Multi-Terminal T-Connected Transmission Lines Based on Interpolation Synchronization" (CN108616111B), uses a sampling interpolation synchronization algorithm to keep the sampled values ​​of the protection devices on each side of the T-connected line synchronized. Each device participating in differential protection is equal, without distinguishing between master and slave devices or adjusting the sampling time. Each device performs differential protection calculations and exchanges protection blocking and enabling signals. However, in this existing technology, the protection devices are connected to each other via fiber optic communication, and signals are transmitted between all devices through the fiber optic cables, reducing the economic efficiency and ease of engineering implementation of the protection device. "A Differential Protection Method and System for Multi-Terminal T-Connected Transmission Lines" (CN105896489B) selects one end of the multi-terminal T-connected transmission line as the synchronization reference end and the remaining ends as synchronization execution ends. It adopts a one-master-multiple-slave approach in the multi-terminal transmission line, with communication connections between the synchronization reference end and each synchronization execution end, while the synchronization execution ends do not communicate with each other, significantly reducing the number of fiber optic channels required. However, with the reduction of fiber optic channels, the execution logic can only be a one-way trip command issued from the synchronous reference end to the synchronous execution end, without involving the execution logic from the synchronous execution end to the synchronous reference end, and without involving the processing of multiple synchronous execution ends issuing trip commands to the synchronous reference end.

[0004] For multi-terminal lines, there will be multiple lines on the opposite side of the line, i.e., multiple circuit breakers. The remote tripping function of the line needs to trip the circuit breakers on each side of the multiple terminals. How to quickly, effectively and correctly disconnect multiple circuit breakers on the opposite side of the line is very important for the research of multi-terminal current differential protection. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for implementing remote tripping and remote transmission functions of multi-terminal current differential protection. When a multi-terminal current differential protection device is applied to a multi-terminal line, it realizes the remote tripping and remote transmission functions of multi-terminal protection. It solves the problems of complex remote tripping and remote transmission signal information interaction between multiple devices, which easily leads to malfunctions and erroneous outputs. It improves the stability of multi-terminal system operation and meets the needs of different line terminal numbers from two ends to multiple ends.

[0006] The present invention adopts the following technical solution.

[0007] This invention proposes a method for implementing remote tripping and remote transmission functions of multi-terminal current differential protection for lines, including:

[0008] Step 1: Select the line protection device configured on the power supply side of the multi-terminal line as the master unit, and the line protection devices configured on the other sides of the multi-terminal line as slave units; the master unit and each slave unit record their respective remote trip signal input and / or remote transmission signal input.

[0009] Step 2: During the information exchange between the master and each slave, based on whether there are remote trip signals or remote transmission signals input between the master and each slave, the transmission path of the remote trip signals or remote transmission signals is adjusted using multi-directional information transmission logic. The multi-directional information transmission logic includes: transmission from master to slave, transmission from slave to master, and multiple transmissions between master and slave. After the remote trip signal undergoes adaptive path adjustment in Step 2, it proceeds to Step 3; after the remote transmission signal undergoes adaptive path adjustment in Step 2, it proceeds to Step 4.

[0010] Step 3: Upon receiving the remote trip signal, the line protection device confirms the signal according to the receiving logic and the corresponding local criteria, and then, after the remote trip delay setting, activates the output to trip the circuit breaker on the line side where the line protection device is located.

[0011] Step 4: The line protection device that receives the remote transmission signal drives the corresponding remote transmission signal output for use by the line protection logic on the other side.

[0012] In step 1, there is only one master on the multi-terminal line, and there is a fiber optic channel between the master and each slave, but no fiber optic channel is set between the slaves.

[0013] Adjusting the transmission path of remote trip signals or remote transmission signals includes:

[0014] First transmission path: When the host receives a remote trip signal or remote transmission signal, the host will transmit the remote trip signal or remote transmission signal to each slave through the corresponding optical fiber channel.

[0015] Second transmission path: When any slave device m has a remote trip signal or remote transmission signal input, the slave device m will transmit the remote trip signal or remote transmission signal to the host through the fiber optic channel. The host records the slave device m that sent the remote trip signal or remote transmission signal and the signal reception time, and forwards the remote trip signal or remote transmission signal to other slave devices after removing slave device m.

[0016] When multiple slave devices receive remote trip signals or remote transmission signals, each slave device will transmit the remote trip signal or remote transmission signal in the order of signal reception time recorded by the master device, following the second transmission path.

[0017] When both the master and slave devices receive remote trip signals or remote transmission signals simultaneously, the remote trip signals or remote transmission signals are transmitted using the cooperation of the first and second transmission paths.

[0018] Local criteria include, but are not limited to: fault current voltage, low current, overcurrent, low active power, and low power factor angle.

[0019] The remote tripping delay setting is determined according to the specifications.

[0020] In step 4, the line protection device includes multiple remote signal input terminals, namely remote signal input terminal 1, remote signal input terminal 2, ..., remote signal input terminal T; using the control word in each frame of data of the digital channel, remote signal 1, remote signal 2, ..., remote signal T are transmitted simultaneously, that is, each optical fiber channel can transmit T remote signals at the same time.

[0021] This invention also proposes a system for realizing the remote tripping and remote transmission functions of multi-terminal current differential protection of a line. The system controls the line protection devices on each side of the multi-terminal line. The line protection device configured on the power supply side of the multi-terminal line is the master, and the line protection devices configured on the other sides of the multi-terminal line are slaves. The system includes: a signal confirmation module, a transmission path adjustment module, and a drive module.

[0022] The signal confirmation module is used to control the host and each slave device to record their respective remote trip signal input and remote transmission signal input;

[0023] The transmission path adjustment module is used to adjust the transmission path of remote trip signals or remote transmission signals based on whether there are remote trip signals or remote transmission signals input between the master and each slave, using multi-directional information transmission logic. The multi-directional information transmission logic includes: master-to-slave transmission, slave-to-master transmission, and multiple transmissions between the master and slave.

[0024] The drive module is used to control the line protection device that receives a remote trip signal. After confirming the signal according to the receiving logic and the corresponding local criteria, it will take action and trip the circuit breaker on the line side where the line protection device is located after the remote trip delay setting. It is also used to control the line protection device that receives a remote transmission signal and drive the corresponding remote transmission signal output for use by the line protection logic on the other side.

[0025] The transmission path adjustment module includes: a first transmission path adjustment unit and a second transmission path adjustment unit;

[0026] The first transmission path adjustment unit is used to control the host to transmit the remote trip signal or remote transmission signal to each slave through the corresponding optical fiber channel when the host has a remote trip signal or remote transmission signal input.

[0027] The second transmission path adjustment unit is used to control the slave m to transmit the remote trip signal or remote transmission signal to the host through the optical fiber channel when any slave m has a remote trip signal or remote transmission signal input. The host records the slave m that sent the remote trip signal or remote transmission signal and forwards the remote trip signal or remote transmission signal to other slaves after removing slave m.

[0028] The beneficial effects of this invention are as follows: Compared with the prior art, the method proposed in this invention for implementing remote tripping and remote transmission functions of multi-terminal current differential protection for lines, after determining the identities of the master and each slave device, enables information exchange between the master and each slave device, and the slave devices are not connected to each other, eliminating the need for direct signal transmission, thereby realizing the processing of tripping or remote transmission signals between all devices. Simultaneously, this invention also proposes multi-directional information processing logic for remote tripping or remote transmission processing. Multi-directional information processing includes master-to-slave, slave-to-master, and more complex multiple interactions between master and slave devices, thereby adaptively adjusting the transmission paths of remote tripping and remote transmission signals, achieving fast, effective, and correct signal transmission, and solving the complex problem of remote tripping and remote transmission signal information exchange between multiple devices in multi-terminal current differential protection devices. Using the implementation method and system proposed in this invention, multiple circuit breakers on the opposite side of the line can be quickly disconnected, improving the stability of the multi-terminal system operation, and enabling rapid and correct remote transmission of each device at multiple ends of the line for use on the opposite side. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the method and system for implementing the remote tripping and remote transmission functions of multi-terminal current differential protection in an embodiment of the present invention, showing a four-terminal line.

[0030] Figure 1 The annotations in the accompanying drawings are explained as follows:

[0031] M, N, O, P - M side, N side, O side, P side of multi-terminal lines;

[0032] T1, T2 - First connection point and second connection point of multi-terminal lines;

[0033] B1, B2, B3, B4 - Circuit breakers on the M side, O side, P side, and N side of multi-terminal lines;

[0034] CT1, CT2, CT3, CT4 - M-side current transformer, O-side current transformer, P-side current transformer, N-side current transformer for multi-terminal lines;

[0035] F1, F2, F3 - First fault point, second fault point, third fault point.

[0036] 10 - Master; 21 - First slave; 22 - Second slave; 23 - Third slave.

[0037] L1 - First fiber optic channel; L2 - Second fiber optic channel; L3 - Third fiber optic channel. Figure 2 This is a flowchart illustrating the steps of the method and system for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection for lines proposed in this invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0039] The remote tripping function of the line differential protection device enables the opposite side protection to trip quickly when there is a bus fault or a fault between the circuit breaker and the current transformer. The line differential protection device is equipped with one or more remote tripping input terminals, which are used to transmit the action signals of bus differential, failure and other protections when the local starting element is started. After receiving this signal, the opposite line differential protection device drives the permanent trip output to trip.

[0040] The remote transmission function of the line differential protection device is that the device on this side is equipped with one or more remote transmission signal input terminals. When the device on this side has a remote transmission input, it can transmit this signal to the device on the other side through the optical fiber channel, driving the device on the other side to output the remote transmission signal for the device on the other side to use.

[0041] Figure 1This is a schematic diagram of the circuit for the implementation method and system of the multi-terminal current differential protection remote tripping and remote transmission functions proposed in this invention. The circuit shown in this embodiment is a four-terminal circuit. The multi-terminal current differential protection devices are installed on the M, N, O, and P sides of the multi-terminal circuit, respectively. The diagram illustrates the current transformers CT1 on the M side, CT2 on the O side, CT3 on the P side, and CT4 on the N side of the multi-terminal circuit, as well as the circuit breakers B1 on the M side, B2 on the O side, B3 on the P side, and the N protection device B4. The first and second connection points of the multi-terminal circuit are T1 and T2, respectively. Because it is a master-slave mode, there is only one master unit, which communicates with each slave unit. The master unit 10 should be installed on the system side, and according to the distance from the master unit from closest to farthest, they are defined as the first slave unit 21, the second slave unit 22, and the third slave unit 23, respectively. The optical fiber longitudinal connection channels between the master unit and each slave unit are defined as the first optical fiber channel L1, the second optical fiber channel L2, and the third optical fiber channel L3, respectively. The master unit is connected to each slave unit via a corresponding fiber optic channel, but the slave units are not connected to each other.

[0042] When a line fault occurs between the circuit breaker and the line protection current transformer, such as Figure 1 The first fault point F1 occurs within the busbar protection's operating range, which is within the dead zone of the line protection. The busbar protection trips circuit breaker B1 on the M side of the line. However, for multi-terminal lines, the first fault point F1 still exists. For the N, O, P, and N sides of the line, the remote tripping function of the line needs to be used to trip the circuit breakers on each side, quickly clearing the fault and reducing its impact on system stability. Similarly, Figure 1 The second fault point F2 in the system is in the same situation.

[0043] This invention proposes a method for implementing the remote tripping and remote transmission functions of multi-terminal current differential protection for lines, such as... Figure 2 As shown, it includes:

[0044] Step 1: Select the line protection device configured on the power supply side of the multi-terminal line as the master unit, and the line protection devices configured on the other sides of the multi-terminal line as slave units; the master unit and each slave unit record their respective remote trip signal input and / or remote transmission signal input; there is an optical fiber channel between the master unit and each slave unit.

[0045] In this embodiment, when determining the identities of the master and slave devices of multiple line protection devices configured on a multi-terminal line, Figure 1The current differential protection device configured on the power supply side is set as the master unit 10, and there is only one master unit on the multi-terminal line; the current differential protection devices configured on the other sides of the multi-terminal line are respectively set as the first slave unit 21, the second slave unit 22 and the third slave unit 23, and a first optical fiber channel L1 is provided between the master unit 10 and the first slave unit 21, a second optical fiber channel L2 is provided between the master unit 10 and the second slave unit 22, and a third optical fiber channel L3 is provided between the master unit 10 and the third slave unit 23.

[0046] Combination Figure 1 In the event of a fault, the following explanation is provided, taking the recording of remote trip signal inputs by the master unit and each slave unit as an example:

[0047] 1. When the fault occurs at the first fault point F1, the bus protection device configured on the bus on the M side of the line trips the circuit breaker B1 on the M side. However, for multi-terminal lines, the first fault point F1 still exists, and the bus protection action signal is connected to the remote trip input of the M side line protection device (main unit 10).

[0048] 2. When the fault occurs at the second fault point F2, the bus protection device configured on the bus on the P side of the line will trip the circuit breaker B3 on the P side and connect the bus protection action signal to the remote trip input of the line protection device (second slave 22) on the P side.

[0049] 3. After the host and each slave device record the remote trip signal input, proceed to step 2.

[0050] The present invention proposes a method for implementing remote tripping and remote transmission functions of multi-terminal current differential protection for power lines. After identifying the master and slave devices, information is exchanged between the master and each slave device, while the slave devices are not interconnected and require no direct signal transmission. This achieves the processing of tripping or remote transmission signals between all devices. By significantly reducing the fiber optic cable laying between slave devices, the method improves both economic efficiency and engineering feasibility while ensuring the realization of line protection functions.

[0051] Step 2: During the information exchange between the master and each slave, based on whether there are remote trip signals or remote transmission signals input between the master and each slave, the transmission path of the remote trip signals or remote transmission signals is adjusted using multi-directional information transmission logic. This multi-directional information transmission logic includes: master-to-slave transmission, slave-to-master transmission, and multiple transmissions between the master and slave; specifically including:

[0052] 1. First transmission path: When the host receives a remote trip signal, it transmits the remote trip signal to each slave unit through the corresponding fiber optic channel.

[0053] In this embodiment, when the fault occurs at the first fault point F1, the host receives a remote trip signal input. The host transmits the remote trip signal to the first slave 21, the second slave 22, and the third slave 23 respectively via the first optical fiber channel L1, the second optical fiber channel L2, and the third optical fiber channel L3.

[0054] 2. Second transmission path: When any slave device m receives a remote trip signal, the slave device m transmits the remote trip signal to the host through the fiber optic channel. The host records the slave device m that received the remote trip signal and the signal reception time, and forwards the remote trip signal to other slave devices after removing slave device m.

[0055] In this embodiment, when the fault occurs at the second fault point F2, the second slave device 22 receives a remote trip signal input and transmits the remote trip signal to the host device 10 via the second optical fiber channel L2. After receiving the remote trip signal, the host device 10 records the second slave device 22 and sends the remote trip signal to the first slave device 21 and the third slave device 23 via the first optical fiber channel L1 and the third optical fiber channel L3.

[0056] 3. When multiple slave devices have remote trip signal inputs, or when multiple slave devices have remote trip signals or remote transmission signals input, each slave device will transmit the remote trip signal or remote transmission signal in sequence according to the order of signal reception time recorded by the master device, following the second transmission path. When both the master device and slave devices have remote trip signal inputs at the same time, the remote trip signal will be transmitted by coordinating the first and second transmission paths.

[0057] When the master receives a remote trip signal or remote transmission signal from multiple slaves, the master first processes the signal received fastest from slave n, and then uses the second transmission path to forward the remote trip signal or remote transmission signal to the other slaves after slave n; other slaves with remote trip signals or remote transmission signals input do not process the signals forwarded by the master again.

[0058] In this embodiment, when the fault occurs at the second fault point F2 and the third fault point F3, the first slave 21 and the second slave 22 have remote trip signal inputs. The first slave 21 transmits the remote trip signal to the host 10 through the third fiber optic channel L3; the second slave 22 transmits the remote trip signal to the host 10 through the second fiber optic channel L2. After the host 10 receives the remote trip signal from the first slave 21, it sends the remote trip signal to the third slave 23 and the second slave 22 through the first fiber optic channel L1 and the second fiber optic channel L2. The second slave 22 does not process the signal forwarded by the host.

[0059] The preceding text used a remote trip signal as an example to explain the remote trip signal transmission process in detail, combining steps 1 and 2. The remote signal transmission process is the same as the remote trip signal transmission process, and will not be repeated here.

[0060] After the remote trip signal undergoes adaptive path adjustment in step 2, it proceeds to step 3; after the remote transmission signal undergoes adaptive path adjustment in step 2, it proceeds to step 4.

[0061] This invention also proposes a multi-directional information processing logic for remote tripping or remote transmission. The multi-directional information processing includes multiple interactions and transmissions between the master and slave, slave and master, and more complex interactions between the master and slave. This adaptively adjusts the transmission paths of the remote tripping signal and the remote transmission signal, enabling fast, effective, and correct signal transmission. It solves the problem of complex interaction of remote tripping and remote transmission signal information between multiple devices in multi-terminal current differential protection devices, and avoids the problems of malfunction and erroneous output.

[0062] Step 3: Upon receiving the remote trip signal, the line protection device confirms the signal according to the receiving logic and corresponding local criteria. After the remote trip delay setting is reached, it trips the circuit breaker on the line side where the line protection device is located. The remote trip delay setting is determined according to the specifications, and its value ranges from 0.01 to 10 seconds.

[0063] The local criteria include, but are not limited to: fault current voltage, low current, overcurrent, low active power, and low power factor angle.

[0064] In this embodiment, when the fault occurs at the first fault point F1, the host records a remote trip signal input. The host transmits the remote trip signal to the first slave 21, the second slave 22, and the third slave 23 respectively through the first fiber optic channel L1, the second fiber optic channel L2, and the third fiber optic channel L3. The first slave 21, the second slave 22, and the third slave 23 trip the circuit breakers B2, B3, and B4 on the line side where each slave is located according to the receiving logic and the corresponding local criteria, quickly clearing the fault and reducing the impact of the fault on system stability.

[0065] In this embodiment, when the fault occurs at the second fault point F2, the second slave device 22 receives a remote trip signal input. The second slave device 22 transmits the remote trip signal to the master device via the second fiber optic channel L2. After receiving the remote trip signal, the master device records the second slave device 22 and sends the remote trip signal to the first slave device 21 and the third slave device 23 via the first fiber optic channel L1 and the third fiber optic channel L3. The first slave device 21 and the third slave device 23 trip the circuit breakers B2 and B4 on the line side where each slave device is located according to the receiving logic and the corresponding local criteria, quickly clearing the fault and reducing the impact of the fault on system stability.

[0066] Step 4: The line protection device that receives the remote transmission signal drives the corresponding remote transmission signal output for use by the line protection logic on the other side.

[0067] The line protection device includes multiple remote signal input terminals, namely remote signal input terminal 1, remote signal input terminal 2, ..., remote signal input terminal T. It simultaneously transmits remote signal 1, remote signal 2, ..., remote signal T using the control word in each frame of data from the digital channel; that is, each fiber optic channel can simultaneously transmit T remote signals. Upon receiving a remote signal, the line protection device drives the corresponding remote signal output.

[0068] The implementation method proposed in this invention can quickly disconnect multiple circuit breakers on the opposite side of the line, improving the stability of the multi-terminal system operation. It can also quickly and correctly drive the remote transmission of various devices at multiple ends of the line for use on the opposite side.

[0069] This invention also proposes a system for implementing remote tripping and remote transmission functions of multi-terminal current differential protection for lines, comprising:

[0070] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0071] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0072] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0073] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0074] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0075] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0076] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0077] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for implementing remote tripping and remote transmission functions of multi-terminal current differential protection for lines, characterized in that, The method includes: Step 1: Select the line protection device configured on the power supply side of the multi-terminal line as the master unit, and the line protection devices configured on the other sides of the multi-terminal line as slave units; the master unit and each slave unit record their respective remote trip signal input and / or remote transmission signal input. Step 2: During the information exchange between the master and each slave, based on whether there are remote trip signals or remote transmission signals input between the master and each slave, the transmission path of the remote trip signals or remote transmission signals is adjusted using multi-directional information transmission logic. The multi-directional information transmission logic includes: transmission from master to slave, transmission from slave to master, and multiple transmissions between master and slave. After the remote trip signal undergoes adaptive path adjustment in Step 2, it proceeds to Step 3; after the remote transmission signal undergoes adaptive path adjustment in Step 2, it proceeds to Step 4. Step 3: Upon receiving the remote trip signal, the line protection device confirms the signal according to the receiving logic and the corresponding local criteria, and then, after the remote trip delay setting, activates the output to trip the circuit breaker on the line side where the line protection device is located. Step 4: The line protection device that receives the remote transmission signal drives the corresponding remote transmission signal output for use by the line protection logic on the other side.

2. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of the line according to claim 1, characterized in that, In step 1, there is only one master on the multi-terminal line, and there is a fiber optic channel between the master and each slave, but no fiber optic channel is set between the slaves.

3. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of the line according to claim 1, characterized in that, Adjusting the transmission path of remote trip signals or remote transmission signals includes: First transmission path: When the host receives a remote trip signal or remote transmission signal, the host will transmit the remote trip signal or remote transmission signal to each slave through the corresponding optical fiber channel. Second transmission path: When any slave device m has a remote trip signal or remote transmission signal input, the slave device m will transmit the remote trip signal or remote transmission signal to the host through the fiber optic channel. The host records the slave device m that sent the remote trip signal or remote transmission signal and the signal reception time, and forwards the remote trip signal or remote transmission signal to other slave devices after removing slave device m.

4. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of the line according to claim 3, characterized in that, When multiple slave devices receive remote trip signals or remote transmission signals, each slave device will transmit the remote trip signal or remote transmission signal in the order of signal reception time recorded by the master device, following the second transmission path.

5. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of the line according to claim 3, characterized in that, When both the master and slave devices receive remote trip signals or remote transmission signals simultaneously, the remote trip signals or remote transmission signals are transmitted using the cooperation of the first and second transmission paths.

6. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of a line according to claim 1, characterized in that, Local criteria include, but are not limited to: fault current voltage, low current, overcurrent, low active power, and low power factor angle.

7. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of a line according to claim 1, characterized in that, The remote tripping delay setting is determined according to the specifications.

8. The method for implementing the remote tripping and remote transmission functions of the multi-terminal current differential protection of a line according to claim 1, characterized in that, In step 4, the line protection device includes multiple remote signal input terminals, namely remote signal input terminal 1, remote signal input terminal 2, ..., remote signal input terminal T; using the control word in each frame of data of the digital channel, remote signal 1, remote signal 2, ..., remote signal T are transmitted simultaneously, that is, each optical fiber channel can transmit T remote signals at the same time.

9. A system for implementing the remote tripping and remote transmission functions of multi-terminal current differential protection for lines using the method described in any one of claims 1-8, wherein the system controls the line protection devices on each side of the multi-terminal line, wherein... The line protection device configured on the power supply side of the multi-terminal line is the master unit, and the line protection devices configured on the other sides of the multi-terminal line are slave units. Its characteristic is that... The system includes: a signal confirmation module, a transmission path adjustment module, and a drive module; The signal confirmation module is used to control the host and each slave device to record their respective remote trip signal input and remote transmission signal input; The transmission path adjustment module is used to adjust the transmission path of remote trip signals or remote transmission signals based on whether there are remote trip signals or remote transmission signals input between the master and each slave, using multi-directional information transmission logic. The multi-directional information transmission logic includes: master-to-slave transmission, slave-to-master transmission, and multiple transmissions between the master and slave. The drive module is used to control the line protection device that receives a remote trip signal. After confirming the signal according to the receiving logic and the corresponding local criteria, it will take action and trip the circuit breaker on the line side where the line protection device is located after the remote trip delay setting. It is also used to control the line protection device that receives a remote transmission signal and drive the corresponding remote transmission signal output for use by the line protection logic on the other side.

10. The system for realizing the remote tripping and remote transmission functions of multi-terminal current differential protection for lines according to claim 9, characterized in that, The transmission path adjustment module includes: a first transmission path adjustment unit and a second transmission path adjustment unit; The first transmission path adjustment unit is used to control the host to transmit the remote trip signal or remote transmission signal to each slave through the corresponding optical fiber channel when the host has a remote trip signal or remote transmission signal input. The second transmission path adjustment unit is used to control the slave m to transmit the remote trip signal or remote transmission signal to the host through the optical fiber channel when any slave m has a remote trip signal or remote transmission signal input. The host records the slave m that sent the remote trip signal or remote transmission signal and forwards the remote trip signal or remote transmission signal to other slaves after removing slave m.

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