Line protection DC panel power failure protection method and system

Abstract

The present invention discloses a power failure protection method for a line protection DC panel, comprising: obtaining a DC panel power input signal of line protection devices on both sides of the line; the line protection devices on both sides are respectively given a virtual input signal; the line protection device on this side transmits the DC panel power input signal and the virtual input signal to the line protection device on the opposite side respectively; the line protection device on each side determines whether the opposite DC panel has power failure by the time difference between the return time of the DC panel power input signal on the opposite side and the return time of the virtual input signal; if the DC panel on the opposite side has power failure, power failure protection is performed. The present invention quickly and accurately determines the power failure of the DC panel by utilizing the time difference between the return time of the DC panel power input signal on the opposite side and the return time of the virtual input signal. Although it is not complicated, it is very clever, and can perform tripping processing on power failure in time, eliminating the risk of unprotected operation of the line at the first time.

Description

Technical Field

[0001] The invention belongs to the technical field of relay protection of electric power systems, and in particular relates to a power failure protection method and system for a line protection DC panel. Background Art

[0002] Two line protection devices are configured on both sides of the transmission line to protect the primary transmission line. The main protection of the line protection device is usually longitudinal differential protection, which is a double-end protection, and transmits information on both sides through the longitudinal channel; the backup protection mainly includes three-stage distance protection, which is a single-end protection. Among them, distance section I usually protects 70%-80% of the total length of the line, and the protection range of distance section II exceeds the total length of the line, but there is a certain action time delay.

[0003] When the DC panel of the line protection device on one side loses power (the power-off side), the line protection device exits operation, and the main protection of the line protection device on the other side (the normal side) cannot operate normally. Only the backup protection continues to operate, and the protection range only covers 70%-80% of the total length of the line, and the protection range is reduced. In addition, when the line fails, the line protection on the normal side cannot trip the switch on the power-off side, which will cause the impact range of the accident to expand and destroy the stable operation of the system. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a line protection DC panel power failure protection method, which can judge and protect the power failure of the DC panel of the opposite side line protection device.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] In a first aspect, a line protection DC panel power failure protection method is provided, comprising:

[0007] Obtain the DC panel power input signal of the line protection devices on both sides of the line;

[0008] The line protection devices on both sides are given a virtual open-in signal respectively;

[0009] The line protection device on this side transmits the DC panel power input signal and the virtual input signal to the line protection device on the opposite side respectively;

[0010] The line protection device on each side determines whether the opposite DC panel loses power by the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal;

[0011] If the DC panel on the opposite side loses power, power failure protection will be performed.

[0012] In combination with the first aspect, further, judging whether the opposite DC panel loses power by the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal includes:

[0013] Given time periods ta and tc, let ta<ts<tc, ts is the time the line protection device maintains power supply after the DC panel power supply fails.

[0014] If ta<td<tc, it is determined that the opposite DC panel has lost power, where td is the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal.

[0015] In combination with the first aspect, further, the power failure protection includes:

[0016] If the second criterion control word of DC power failure protection is 0, it will trip directly after a given delay tck;

[0017] If the second criterion control word of the DC power failure protection is 1, the same method is used to determine whether the DC panel on the opposite side has power failure. If it is still determined to be power failure, it will trip after a given delay tck, otherwise it will not trip.

[0018] In combination with the first aspect, further, the tck is 1s.

[0019] In a second aspect, a line protection DC screen power failure protection system is provided, comprising:

[0020] A signal acquisition module, used to obtain the DC panel power input signal of the line protection devices on both sides of the line;

[0021] The line protection devices on both sides are given a virtual open-in signal respectively;

[0022] The line protection device on this side transmits the DC panel power input signal and the virtual input signal to the line protection device on the opposite side respectively; the power failure judgment module is used for the line protection device on each side to judge whether the opposite DC panel has power failure by the time difference between the return time of the DC panel power input signal on the opposite side and the return time of the virtual input signal;

[0023] The power failure protection module is used to provide power failure protection if the DC panel on the opposite side loses power.

[0024] In combination with the second aspect, further, the content executed by the power failure judgment module includes: given time periods ta and tc, let ta<ts<tc, ts is the time that the line protection device maintains power supply after the DC panel power supply is powered off, if ta<td<tc, then it is determined that the opposite side DC panel has lost power, wherein td is the time difference between the return moment of the opposite side DC panel power input signal and the return moment of the virtual input signal.

[0025] In a third aspect, a line protection DC panel power failure protection system is characterized by comprising:

[0026] including memory and processor;

[0027] The memory is used to store instructions;

[0028] The processor is used to operate according to the instructions to execute the steps of the method according to any one of the first aspects.

[0029] Beneficial effects of the invention: The invention can quickly and accurately determine the power failure of the DC panel by utilizing the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal. Although it is not complicated, it is very clever, and can perform tripping processing in time for power failure, eliminating the risk of unprotected line operation at the first time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of signal access in the present invention;

[0031] Figure 2 It is a flow chart of the logic implementation of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0033] In order to better understand the present invention, the relevant technologies in the technical solution of the present invention are explained below.

[0034] Example 1

[0035] like Figure 1-Figure 2 As shown, a line protection DC panel power failure protection method of the present invention comprises the following steps:

[0036] Step 1: Signal acquisition

[0037] The line protection device is connected to an open input contact of the line protection device through the DC source of the line protection device panel cabinet. This open input contact is the external open input signal. When the DC panel is normal, this open input is 1, and when the DC panel loses power, this open input is 0.

[0038] The line protection device sets a virtual input signal through software and sets it to 1.

[0039] The channel information of the line protection device is increased by two input quantities and transmitted to the opposite side, which are the above-mentioned external input signal and virtual input signal.

[0040] Step 2: DC panel power failure judgment

[0041] Since the power supply of the line protection device can maintain normal power supply for ts=100ms after power failure, when the moment when the virtual input signal received by the line protection device on this side changes from 1 to 0 lags behind the moment when the external input signal changes from 1 to 0, we use this time difference to judge the power failure, given the time period ta=50ms and tc=200ms (set according to experience), let ta<ts<tc.

[0042] If ta<td<tc, it is determined that the opposite DC panel has lost power, where td is the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal.

[0043] Step 3: Power failure protection

[0044] The present invention adopts a double set of protection devices. In step 2, the first set of protection devices is used to determine whether power is lost. The subsequent judgment is based on the first set of protection devices judging that power is lost.

[0045] Before starting the power failure protection (whether to pull the switch), we first judge the second criterion control word of the DC power failure protection. If the second criterion control word of the DC power failure protection is 0, it means that the system does not need to judge the second set of protection, and it will directly trip after the given delay tck to complete the protection. If the second criterion control word of the DC power failure protection is 1, it means that the second set of protection is needed to confirm the power failure again, and then the same method in step 2 of the second set of protection device is used to judge whether the DC panel on the opposite side has power failure. If it is still judged to be power failure, it will trip after the given delay tck, otherwise it will not trip. Here we set the duration of tck to 1s.

[0046] Example 2

[0047] The present invention also provides a line protection DC panel power failure protection system, comprising:

[0048] A signal acquisition module, used to obtain the DC panel power input signal of the line protection devices on both sides of the line;

[0049] The line protection devices on both sides are given a virtual open-in signal respectively;

[0050] The line protection device on this side transmits the DC panel power input signal and the virtual input signal to the line protection device on the opposite side respectively; the power failure judgment module is used for the line protection device on each side to judge whether the opposite DC panel has power failure by the time difference between the return time of the DC panel power input signal on the opposite side and the return time of the virtual input signal;

[0051] The power failure protection module is used to provide power failure protection if the DC panel on the opposite side loses power.

[0052] Example 3

[0053] A line protection DC panel power failure protection system, comprising:

[0054] including memory and processor;

[0055] The memory is used to store instructions;

[0056] The processor is used to operate according to the instructions to execute the steps of any one of the line protection DC panel power failure protection methods.

[0057] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0058] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0059] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0060] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A line protection DC panel power failure protection method, characterized in that: include: Get the DC panel power input signal of the line protection device on both sides of the line. When the DC panel is normal, this input is 1, and when the DC panel loses power, this input is 0; The line protection devices on both sides are given a virtual input signal, which is fixed at 1; The line protection device on this side transmits the DC panel power input signal and the virtual input signal to the line protection device on the opposite side respectively; The line protection device on each side determines whether the opposite DC panel loses power by the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal; If the DC panel on the opposite side loses power, power failure protection will be performed; The method of judging whether the opposite DC panel loses power by the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal includes: Given time periods ta and tc, let ta<ts<tc, ts is the time the line protection device maintains power supply after the DC panel power supply fails. If ta<td<tc, it is determined that the DC panel on the opposite side has lost power, where td is the time difference between the moment when the power input signal of the DC panel on the opposite side returns and the moment when the virtual input signal returns.

2. A line protection DC panel power failure protection method according to claim 1, characterized in that: The power failure protection includes: If the second criterion control word of DC power failure protection is 0, it will trip directly after a given delay tck; If the second criterion control word of the DC power failure protection is 1, the same method is used to determine whether the DC panel on the opposite side has power failure. If it is still determined to be power failure, it will trip after a given delay tck, otherwise it will not trip.

3. A line protection DC panel power failure protection method according to claim 2, characterized in that: The tck is 1s.

4. A line protection DC panel power failure protection system, characterized in that: include: The signal acquisition module is used to obtain the DC panel power input signal of the line protection device on both sides of the line. When the DC panel is normal, this input is 1, and when the DC panel loses power, this input is 0; The line protection devices on both sides are given a virtual input signal, which is fixed at 1; The line protection device on this side transmits the DC panel power input signal and the virtual input signal to the line protection device on the opposite side respectively; A power failure judgment module is used for the line protection device on each side to judge whether the opposite DC panel has power failure by the time difference between the return time of the power input signal of the opposite DC panel and the return time of the virtual input signal; Power failure protection module, used for power failure protection if the DC panel on the opposite side loses power; The contents executed by the power failure judgment module include: given time periods ta and tc, let ta<ts<tc, ts is the time that the line protection device maintains power supply after the DC panel power supply is powered off; if ta<td<tc, it is determined that the opposite DC panel has lost power, wherein td is the time difference between the return moment of the opposite DC panel power input signal and the return moment of the virtual input signal.

5. A line protection DC panel power failure protection system, characterized in that: include: including memory and processor; The memory is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 3.

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