An anti-over-tripping device and method for underground electro-optical high-security switch

Abstract

The application discloses a downhole electric-optical high-protection switch overstep trip-out prevention device and method, which comprises a plurality of transformer substations divided by levels, each of the transformer substations comprises a plurality of branch switches and a plurality of total switches, each of the switches is configured with a protector, and all of the transformer substations comprise a bus connected with a power grid; in a single transformer substation, all of the total switches are connected in series to the bus of the transformer substation through electric wires, the protectors of the branch switches are connected in stages through optical fibers and connected to the protector of the highest-stage total switch, the highest-stage total switch of each transformer substation is connected with the lowest-stage total switch of the upper transformer substation through an electric wire, and the protector of the highest-stage total switch of each transformer substation is connected with the protector of the lowest-stage total switch of the upper transformer substation through an optical fiber; the application has the advantages that the downhole power supply system is suitable for a downhole power supply system without small time delay of a ground-to-well line control switch.

Description

Technical Field

[0001] The present invention relates to the field of coal mine safety protection, and more particularly to an underground electro-optical high-security switch anti-over-tripping device and method. Background Art

[0002] Overtripping occurs when a power system fault occurs and a circuit breaker with a specific protection setting trips first, but another circuit breaker trips to clear the fault. In coal mines, overtripping can cause widespread power outages, severely impacting production and easily leading to accidents. This is an urgent issue facing coal mine power supply systems.

[0003] like Figure 1 As shown, existing underground over-tripping protection utilizes an electro-optical permanent magnet high-security switch equipped with an electro-optical DGG-660G protection device. This protection configuration includes an over-tripping protection feature. However, because many high-voltage lines in coal mines are short and have large cable capacities, the short-circuit currents generated by short circuits at the end of the line and at the exit are similar. Relying solely on current settings cannot guarantee protection selectivity, and over-tripping is inevitable. Typically, a time differential between the upper and lower level switches is used to ensure protection selectivity, somewhat mitigating over-tripping incidents. The DGG-660G high-security protection device's short-circuit quick-break protection function is configured as follows: The end-line short-circuit protection utilizes a zero-time quick-break, while the upper level adds a time differential Δt, where Δt = K × (protection judgment time + protection exit time + switch inherent trip time). K is the reliability factor, generally set to 1.5. The sum of the protection judgment time and protection exit time of the DGG-660G high-explosive protection device is no more than 30ms. The typical value of the inherent opening time of the existing high-explosive switch is less than 70ms, and the total tripping time of the high-explosive switch does not exceed 100ms. Figure 1 The timing coordination of each switch is as follows: the trip delay for switch #7 is 0ms; the trip delay for switches #5 and #6 is 150ms; and the trip delay for switches #3 and #4 is 300ms. Considering that there is still 70ms before switches #1 and #2 open, if a setting of 450ms plus the switch opening time exceeds 500ms, for safety reasons, the trip delay for switches #1 and #2 is set to 300ms. While resolving the short-circuit tripping issue with a small delay is simple and easy, it is not suitable for underground power supply systems where the surface access line control switches lack a small delay. Furthermore, if the line connected to the upper switch is short-circuited, the switch's quick-break protection tripping speed will be slow due to the delay. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing underground anti-over-tripping device and method are not suitable for the underground power supply system where the ground-entry line control switch has no small delay.

[0005] The present invention solves the above technical problems through the following technical means: an underground electro-optical high-security switch anti-over-tripping device, comprising a plurality of substations divided into levels, each substation comprising a plurality of branch switches and a plurality of main switches, each switch being equipped with a protector, and all substations comprising a busbar connected to a power grid;

[0006] In a single substation, all main switches are connected in series to the busbar of the substation via wires. The main switch closest to the busbar is the highest-level main switch, and the main switch farthest from the busbar is the lowest-level main switch. All sub-switches are connected to the busbar of the substation via wires. The protectors of the sub-switches are connected to the protector of the highest-level main switch via optical fibers, and the protectors of all main switches are connected to each other via optical fibers, one level at a time, and to the protector of the highest-level main switch.

[0007] Between substations, the highest-level main switch of each substation is connected to the lowest-level main switch of its upper substation through wires; the protector of the highest-level main switch of each substation is connected to the protector of the lowest-level main switch of its upper substation through optical fibers;

[0008] If the current value of the power supply system connected to the current switch reaches the quick-break condition, the protector corresponding to the current switch will output a locking control signal on the optical fiber, the current switch will start the quick-break trip, and at the same time, the quick-break backup function of the lower-level protection will be activated.

[0009] The present invention provides an anti-over-tripping device, which outputs a locking control signal on the optical fiber through the protector corresponding to the current switch, locks the quick-break function of the upper switch protection to prevent the upper switch from over-tripping, and simultaneously starts the quick-break backup function of the lower protection. The upper switch protection serves as the backup protection of the lower switch. Even if the lower switch refuses to operate, the quick-break protection will not be lost, so that the power supply system under each level of switch can be quickly tripped when short-circuited. The tripping speed is not slowed down due to the delay of the quick-break protection, and there is no need to set the switch delay. It is safe and reliable and suitable for underground power supply systems with no small delay in the ground-entry well line control switches.

[0010] Preferably, the several substations divided by hierarchy are horizontal substations, central substations and ground substations in sequence, the upper substation of the horizontal substation is the central substation, the highest-level main switch of the horizontal substation is connected to the lowest-level main switch of the central substation through wires, the upper substation of the central substation is the ground substation, the highest-level main switch of the central substation is connected to the lowest-level main switch of the ground substation through wires.

[0011] Preferably, the optical fiber includes a first optical fiber and a second optical fiber. In the single substation, the transmitting end of the protector of the sub-switch is connected to the receiving end of the protector of the adjacent sub-switch through the first optical fiber, and is connected to the receiving end of the protector of the highest-level main switch through a hierarchical connection of the first optical fiber; the transmitting end of the protector of the lowest-level main switch is connected to the receiving end of the protector of the adjacent main switch through the second optical fiber, and is connected to the receiving end of the protector of the highest-level main switch through a hierarchical connection of the second optical fiber.

[0012] Preferably, between the substations, the transmitting end of the protector of the highest-level main switch of each substation is connected to the receiving end of the protector of the lowest-level main switch of its upper substation through a second optical fiber.

[0013] Preferably, the model of the protector is DGG-660G.

[0014] The present invention also provides a method for preventing over-tripping of an underground electro-optical high-protection switch, the method comprising: if the current value of the power supply system connected to the current switch reaches the quick-break condition, the protector corresponding to the current switch will output a locking control signal on the optical fiber, the action time is 12ms, and the current switch starts the quick-break trip. When the quick-break condition disappears, the locking control signal on the optical fiber disappears. The locking control signal output on the optical fiber is used to lock the quick-break protection function of the upper switch of the current switch to prevent over-tripping of the upper switch.

[0015] Preferably, the method also includes: if the protector corresponding to the current switch receives the locking control signal of the lower-level switch of the current switch, the quick-break function of the protector corresponding to the current switch is locked to prevent the current switch from tripping beyond the level, and at the same time, the lower-level protection quick-break backup function is started. When it is detected that the lower-level switch of the current switch cannot start the quick-break tripping due to a fault, the quick-break tripping is started through the current switch, and at the same time, the current switch sends a locking control signal, and the upper-level switch of the current switch receives the locking control signal, and the quick-break protection function of the upper-level switch of the current switch is locked to prevent the upper-level switch of the current switch from tripping beyond the level.

[0016] Preferably, the method also includes: when the locking control signal disappears, the protector reports the lock return, and at the same time opens the quick-break protection function of the upper switch of the current switch, cancels the quick-break backup function of the lower-level protection, completes the current round of over-tripping locking function, and waits for the next fault to occur.

[0017] The advantages of the present invention are: the present invention adopts an anti-over-tripping device, which outputs a locking control signal on the optical fiber through the protector corresponding to the current switch, locks the quick-break function of the upper switch protection, prevents the upper switch from over-tripping, and starts the quick-break backup function of the lower protection at the same time. The upper switch protection serves as the backup protection of the lower switch. Even if the lower switch refuses to move, the quick-break protection will not be lost, so that the power supply system under each level of switch can be quickly tripped when short-circuited. The tripping speed is not slowed down due to the delay of the quick-break protection, and there is no need to set the switch delay. It is safe and reliable and suitable for underground power supply systems where the ground-entering well line control switches have no small delay. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of an anti-over-tripping device in the prior art;

[0019] Figure 2 The present invention is a schematic diagram of an anti-over-tripping device for an underground electro-optical high-security switch disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] Example 1

[0022] like Figure 2 As shown, an underground electro-optical high-security switch anti-over-tripping device includes several substations divided by levels, specifically Figure 2 Taking the device schematic diagram shown as an example, in actual application, the number of switches and the number of substations can be more or less than the diagram. The present invention aims to protect this wiring method and the idea of ​​preventing over-tripping, and does not impose any special restrictions on the number of switches and the number of substations.

[0023] The substations divided into several levels are horizontal substations, central substations and ground substations. The upper level substation of the horizontal substation is the central substation, and the upper level substation of the central substation is the ground substation. Each substation includes several branch switches and several main switches. Figure 2As shown, the horizontal substation includes a main switch SZ1, branch switches SF1, and SF2; the central substation includes main switches ZZ1, ZZ2, branch switches ZF1, and ZF2; and the ground substation includes main switches DZ1 and DZ2. Each switch is equipped with a DGG-660G protector. All substations have a busbar 1 connected to the grid.

[0024] In a single substation, all main switches are connected in series to the busbar 1 of the substation where they are located through wires 2. For example, one end of the main switch DZ1 is connected in series with the main switch DZ2 and the other end of the main switch DZ1 is connected to the busbar 1 of the ground substation where it is located. The main switch closest to the busbar 1 is the highest-level main switch, such as the main switch DZ1 is the highest-level main switch in the ground substation, the main switch ZZ1 is the highest-level main switch in the central substation, and the main switch SZ1 is the highest-level main switch in the horizontal substation. The main switch farthest from the busbar 1 is the lowest-level main switch, such as the main switch DZ2 is the lowest-level main switch in the ground substation, the main switch ZZ2 is the lowest-level main switch in the central substation, and the lowest-level main switch of the horizontal substation is not shown in the figure. All branch switches are connected to the busbar 1 of the substation where they are located through wires 2. For example, Figure 2 In the figure, the sub-switch ZF1 and the sub-switch ZF2 are connected to the bus 1 of the central substation of the substation where they are located through the wire 2, and the sub-switch SF1 and the sub-switch SF2 are connected to the bus 1 of the horizontal substation of the substation where they are located through the wire 2.

[0025] Between substations, the highest level main switch of each substation is connected to the lowest level main switch of its upper substation through wire 2; the protector of the highest level main switch of each substation is connected to the protector of the lowest level main switch of its upper substation through optical fiber; Figure 2 The highest level main switch SZ1 of the horizontal substation is connected to the lowest level main switch ZZ2 of the central substation through wire 2, and the highest level main switch ZZ1 of the central substation is connected to the lowest level main switch DZ2 of the ground substation through wire 2.

[0026] The present invention provides an underground electro-optical high-security switch anti-over-tripping device comprising an optical fiber, wherein the optical fiber comprises a first optical fiber CH1 and a second optical fiber CH2. In a single substation, the transmitting end TX of the protector of the sub-switch is connected to the receiving end RX of the protector of the adjacent sub-switch via the first optical fiber CH1, and is connected to the receiving end RX of the protector of the highest-level main switch via the hierarchical connection of the first optical fiber CH1. Figure 2Taking a horizontal substation as an example, the transmitting end TX of the protector of a sub-switch SF2 is connected to the receiving end RX of the protector of its adjacent sub-switch SF1 via a first optical fiber CH1. If there are more than two sub-switches, the transmitting end TX is connected to the receiving end RX of the protector of the highest-level main switch SZ1 via a hierarchical connection of the first optical fiber CH1. The transmitting end TX of the protector of the lowest-level main switch is connected to the receiving end RX of the protector of its adjacent main switch via a second optical fiber CH2. Then, the transmitting end TX of the protector of the highest-level main switch is connected to the receiving end RX of the protector of the lowest-level main switch via a hierarchical connection of the second optical fiber CH2. Taking a horizontal substation as an example, the lowest-level main switch of the horizontal substation is not shown. The transmitting end TX of the protector of the lowest-level main switch is connected to the receiving end RX of the protector of its adjacent main switch via a second optical fiber CH2. If there are more than two main switches in the horizontal substation, the transmitting end TX of the protector of the lowest-level main switch is connected to the receiving end RX of the protector of the highest-level main switch SZ1 via a hierarchical connection of the second optical fiber CH2.

[0027] Between the substations, the transmitting end TX of the protector of the highest level main switch of each substation is connected to the receiving end RX of the protector of the lowest level main switch of its upper substation through the second optical fiber CH2. Figure 2 The transmitting end TX of the protector of the highest-level main switch SZ1 of the horizontal substation is connected to the receiving end RX of the protector of the lowest-level main switch ZZ2 of its upper-level substation (central substation) via a second optical fiber CH2. The transmitting end TX of the protector of the highest-level main switch ZZ1 of the central substation is connected to the receiving end RX of the protector of the lowest-level main switch DZ2 of its upper-level substation (ground substation) via a second optical fiber CH2. The transmitting end TX of the protector of the highest-level main switch DZ1 of the ground substation is connected to the receiving end RX of the protector of the lowest-level main switch of its upper-level substation (ground substation) via a second optical fiber CH2.

[0028] The principle of the present invention is: the DGG-660G protector has built-in quick-break conditions and a circuit to prevent over-tripping caused by short circuits. The circuit to prevent over-tripping caused by short circuits belongs to the prior art and is not within the protection scope of this application. If the current value of the power supply system connected to the current switch reaches the quick-break condition, that is, the power supply system connected to the current switch is short-circuited, the protector corresponding to the current switch detects a large current, and the protector corresponding to the current switch will output a locking control signal on the optical fiber with an action time of 12ms. The current switch starts the quick-break trip. When the quick-break condition disappears, the locking control signal on the optical fiber disappears. The locking control signal output on the optical fiber is used to lock the quick-break protection function of the upper switch of the current switch to prevent over-tripping of the upper switch.

[0029] Through the above technical scheme, the present invention provides an underground electro-optical high-security switch anti-overtripping device, which outputs a locking control signal on the optical fiber through the protector corresponding to the current switch, locks the quick-break function of the upper switch protection to prevent the upper switch from overtripping, and simultaneously starts the quick-break backup function of the lower protection. The upper switch protection serves as the backup protection of the lower switch. Even if the lower switch refuses to move, the quick-break protection will not be lost, so that the power supply system under each level of switch can be quickly broken and tripped when short-circuited. The tripping speed is not slowed down due to the delay of the quick-break protection, and there is no need to set the switch delay. It is safe and reliable and suitable for underground power supply systems with no small delay in the ground-entry line control switch.

[0030] Example 2

[0031] Continue reading Figure 2 , Embodiment 2 of the present invention corresponding to Embodiment 1 of the present invention further provides a method for an underground electro-optical high-protection switch anti-overtripping device, the method comprising: if the current value of the power supply system connected to the current switch reaches the quick-break condition, the protector corresponding to the current switch will output a locking control signal on the optical fiber, the action time is 12ms, and the current switch starts the quick-break tripping. When the quick-break condition disappears, the locking control signal on the optical fiber disappears. The locking control signal output on the optical fiber is used to lock the quick-break protection function of the upper switch of the current switch to prevent the upper switch from overtripping.

[0032] by Figure 2 Taking the horizontal substation as an example, in the horizontal substation, if the power supply line connected to the main switch SZ1 has a short circuit fault, the main switch SZ1 detects a large current, and the protector corresponding to the main switch SZ1 outputs a locking control signal. Because the main switch SZ1 is the lowest level where the fault point is located, the main switch SZ1 starts the quick-break tripping to avoid large-scale power outages. The protector corresponding to the main switch SZ1 outputs a locking control signal, so that its upper-level switch, that is, the main switch ZZ2 of the central substation and the sub-switch SF1 of the horizontal substation, locks the quick-break protection function to prevent the main switch ZZ2 and the sub-switch SF1 from tripping across the level.

[0033] The method further includes: if the protector corresponding to the current switch receives a blocking control signal from a downstream switch of the current switch, blocking the quick-break function of the protector corresponding to the current switch to prevent overtripping of the current switch, and simultaneously activating a quick-break backup function of the downstream protection. If it is detected that the downstream switch of the current switch cannot initiate quick-break tripping due to a fault, quick-break tripping is initiated by the current switch, and the current switch sends a blocking control signal. The upstream switch of the current switch receives the blocking control signal, blocking the quick-break protection function of the upstream switch of the current switch to prevent overtripping of the upstream switch of the current switch. Even if the downstream switch of the current switch fails to operate due to a fault, the quick-break protection will not be lost.

[0034] by Figure 2Taking the central substation and horizontal substation as an example, if the protector corresponding to main switch ZZ2 receives a blocking control signal from main switch SZ1, the quick-break function of the corresponding protector of main switch ZZ2 is blocked to prevent main switch ZZ2 from overtripping. At the same time, the quick-break backup function of the lower-level protection is activated. If it detects that main switch SZ1 cannot initiate quick-break tripping due to a fault, quick-break tripping is initiated through main switch ZZ2. At the same time, main switch ZZ2 sends a blocking control signal. Main switch ZZ1 receives the blocking control signal and blocks the quick-break protection function of main switch ZZ1, preventing main switch ZZ2 from overtripping. Even if main switch SZ1 fails to operate due to a fault, the quick-break protection function will not be lost.

[0035] The method also includes: when the locking control signal disappears, the protector reports the lock return, and at the same time opens the quick-break protection function of the upper switch of the current switch, cancels the quick-break backup function of the lower protection, completes the current round of over-level tripping locking function, and waits for the next fault to occur. Figure 2 Taking the central substation and horizontal substation as an example, when the locking control signal transmitted in the optical fiber disappears, the protector corresponding to the main switch ZZ1 reports the lock return, and at the same time opens the quick-break protection function of the main switch ZZ1, cancels the quick-break backup function of the lower-level protection, completes the current round of over-tripping locking function, and waits for the next fault to occur.

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An underground electro-optical high-security switch anti-over-tripping device, characterized in that: It includes several substations divided into levels, each substation includes several branch switches and several main switches, each switch is equipped with a protector, and all substations include busbars connected to the power grid; In a single substation, all main switches are connected in series to the busbar of the substation via wires. The main switch closest to the busbar is the highest-level main switch, and the main switch farthest from the busbar is the lowest-level main switch. All sub-switches are connected to the busbar of the substation via wires. The protectors of the sub-switches are connected to the protector of the highest-level main switch via optical fibers, and the protectors of all main switches are connected to each other via optical fibers, one level at a time, and to the protector of the highest-level main switch. Between substations, the highest-level main switch of each substation is connected to the lowest-level main switch of its upper substation through wires; the protector of the highest-level main switch of each substation is connected to the protector of the lowest-level main switch of its upper substation through optical fibers; If the current value of the power supply system connected to the current switch reaches the quick-break condition, the protector corresponding to the current switch will output a locking control signal on the optical fiber, the current switch will start the quick-break trip, and at the same time, the quick-break backup function of the lower-level protection will be activated; If the protector corresponding to the current switch receives the blocking control signal from the lower-level switch of the current switch, the quick-break function of the protector corresponding to the current switch is blocked to prevent the current switch from tripping at an over-level. At the same time, the quick-break backup function of the lower-level protection is started. When it is detected that the lower-level switch of the current switch cannot start the quick-break trip due to a fault, the quick-break trip is started through the current switch. At the same time, the current switch sends a blocking control signal. The upper-level switch of the current switch receives the blocking control signal and blocks the quick-break protection function of the upper-level switch of the current switch to prevent the upper-level switch of the current switch from tripping at an over-level. When the locking control signal disappears, the protector reports the lock return, and at the same time opens the quick-break protection function of the upper switch of the current switch, cancels the quick-break backup function of the lower protection, completes the current round of over-tripping locking function, and waits for the next fault to occur.

2. The underground electro-optical high-security switch anti-over-tripping device according to claim 1, characterized in that: The several substations divided into levels are horizontal substations, central substations and ground substations. The upper substation of the horizontal substation is the central substation. The highest-level main switch of the horizontal substation is connected to the lowest-level main switch of the central substation through wires. The upper substation of the central substation is the ground substation. The highest-level main switch of the central substation is connected to the lowest-level main switch of the ground substation through wires.

3. The underground electro-optical high-security switch anti-over-tripping device according to claim 1, characterized in that: The optical fiber includes a first optical fiber and a second optical fiber. In the single substation, the transmitting end of the protector of the sub-switch is connected to the receiving end of the protector of the adjacent sub-switch through the first optical fiber, and is connected to the receiving end of the protector of the highest-level main switch through a hierarchical connection of the first optical fiber; the transmitting end of the protector of the lowest-level main switch is connected to the receiving end of the protector of the adjacent main switch through the second optical fiber, and is connected to the receiving end of the protector of the highest-level main switch through a hierarchical connection of the second optical fiber.

4. The underground electro-optical high-security switch anti-over-tripping device according to claim 3, characterized in that: Between the substations, the transmitting end of the protector of the highest-level main switch of each substation is connected to the receiving end of the protector of the lowest-level main switch of its upper substation through a second optical fiber.

5. The underground electro-optical high-security switch anti-over-tripping device according to claim 1, characterized in that: The model of the protector is DGG-660G.

6. A method for preventing over-tripping of an underground electro-optical high-security switch according to any one of claims 1 to 5, characterized in that: The method includes: if the current value of the power supply system connected to the current switch reaches the quick-break condition, the protector corresponding to the current switch will output a locking control signal on the optical fiber, the action time is 12ms, and the current switch starts to trip quickly. When the quick-break condition disappears, the locking control signal on the optical fiber disappears. The locking control signal output on the optical fiber is used to lock the quick-break protection function of the upper switch of the current switch to prevent the upper switch from tripping.

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