10kV and 20kV interconnecting transformer protection device and implementation method thereof

Abstract

The invention provides an implementation method of a 10kV and 20kV interconnecting transformer protection device, which comprises the following steps of: detecting the opening and closing states of section switches FDL1 and FDL2 when the load side of an interconnecting transformer has a fault; according to the opening and closing states of the section switches FDL1 and FDL2, one of three backup protection constant values is selected to execute backup protection tripping logic correspondingly configured according to a power supply side power supply mode and overcurrent protection three-section time limit, and the section switches and interconnecting transformer switches which are correspondingly closed are sequentially driven to trip off to realize backup protection; wherein the power supply side power supply mode comprises a 10kV bus single-side power supply mode, a 20kV bus single-side power supply mode and a 10kV and 20kV bus parallel power supply mode; and the third over-current protection time limit comprises a first over-current protection time limit, a second over-current protection time limit and a third over-current protection time limit. By means of the method, mistaken tripping of partial section switches can be avoided, and the overcurrent impact phenomenon of 10kV and 20kV interconnecting transformers can be avoided by tripping off the corresponding switches in batches based on the overcurrent protection three-section time limit protection mode.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a protection device for a 10kV and 20kV interconnection transformer and its implementation method. Background Technology

[0002] To address issues such as insufficient power supply and excessive voltage drop in rural areas, one approach is to upgrade the distribution network from 10kV to 20kV. However, upgrading a 10kV distribution network to 20kV is a long-term, systematic project, with construction lasting 10-15 years (or even 20 years). This means that not all power supply areas within the 10kV distribution network upgrade zone have the immediate conditions and opportunity for voltage upgrades, inevitably resulting in areas where 10kV and 20kV power sources are mixed.

[0003] Currently, during the renovation of areas with mixed 10kV and 20kV power supply, it is necessary to ensure the reliable operation of the system while also considering the interconnection between the original 10kV distribution network and the newly constructed 20kV distribution network. At this time, if... Figure 1 As shown, areas with mixed 10kV and 20kV power supply (such as...) Figure 1 Within the area indicated by the dashed box, the 10kV and 20kV interconnection transformer connects the newly constructed 20kV distribution network bus 1M with the 20kV distribution network bus 2M in the 110kV to 20kV power supply area via sectionalizing switch FDL2, and connects the newly constructed 10kV distribution network bus 2M with the 10kV distribution network 1M in the 110kV to 10kV power supply area via sectionalizing switch FDL1. Furthermore, corresponding protection devices are configured for operation protection to isolate faults and prevent the escalation of power grid accidents. The 10kV and 20kV interconnection transformer is connected to the newly constructed 10kV distribution network bus 2M via interconnection transformer switch DL3, and to the newly constructed 20kV distribution network bus 1M via interconnection transformer switch DL4.

[0004] To ensure that the 10kV and 20kV interconnection transformers do not trip due to load-side faults under different power supply modes (e.g., controlled by the opening and closing states of sectionalizing switches FDL1 and FDL2), the protection device for the 10kV and 20kV interconnection transformers is connected to sectionalizing switches FDL1, FDL2, interconnection transformer switch DL3, and interconnection transformer switch DL4 for backup protection tripping.

[0005] However, when the existing protection device for the 10kV and 20kV interconnection transformer trips for backup protection, on the one hand, it does not consider the power supply mode of the power source side and performs simultaneous trip control of all connected switches, which causes some sectional switches to trip erroneously and triggers a chain reaction of tripping switches on the corresponding power supply side. On the other hand, because the tripping sequence of the connected switches is not sequential, there is an overcurrent impact phenomenon on the 10kV and 20kV interconnection transformer. Summary of the Invention

[0006] The technical problem to be solved by the embodiments of the present invention is to provide a protection device for a 10kV and 20kV interconnection transformer and its implementation method. This device can not only avoid the problem of cascading tripping of the corresponding power supply side caused by the erroneous tripping of some sectionalizing switches, but also automatically adapt to different backup protection settings to trip the corresponding switches in batches based on the three-stage time-limit overcurrent protection mode, so as to avoid the overcurrent impact phenomenon of the 10kV and 20kV interconnection transformer.

[0007] To address the aforementioned technical problems, this invention provides a method for implementing a protection device for a 10kV and 20kV interconnection transformer, the method comprising the following steps: S1. When a fault occurs on the load side of the 10kV and 20kV interconnection transformer, check the opening and closing status of sectionalizing switch FDL1 and sectionalizing switch FDL2. S2. Based on the detected opening and closing states of sectionalizing switches FDL1 and FDL2, select one of the three preset backup protection settings to execute the backup protection tripping logic configured according to the power supply mode and the three-stage overcurrent protection time limit. This sequentially drives the corresponding closed sectionalizing switches and tie transformer switches to trip, thereby achieving backup protection for the 10kV and 20kV tie transformers. The power supply mode includes a 10kV distribution network bus single-side power supply mode, a 20kV distribution network bus single-side power supply mode, and a 10kV distribution network bus and 20kV distribution network bus parallel power supply mode. The three-stage overcurrent protection time limit includes overcurrent protection time limit TGL1, overcurrent protection time limit 2, and overcurrent protection time limit 3.

[0008] Specifically, step S2 includes: If it is detected that the sectionalizing switch FDL1 is in the closed state and the sectionalizing switch FDL2 is in the open state, then the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the 10kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL4, the overcurrent protection two time limit trips the tie transformer switch DL3, and the overcurrent protection three time limit trips the sectionalizing switch FDL1. Based on the determined backup protection tripping logic, the interconnection transformer switch DL4, interconnection transformer switch DL3 and the sectionalizing switch FDL1 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

[0009] Step S2 further includes: If it is detected that the sectionalizing switch FDL1 is in the open state and the sectionalizing switch FDL2 is in the closed state, then the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the single-side power supply mode of the 20kV distribution network bus, the overcurrent protection one time limit trips the tie transformer switch DL3, the overcurrent protection two time limit trips the tie transformer switch DL4, and the overcurrent protection three time limit trips the sectionalizing switch FDL2. Based on the determined backup protection tripping logic, the interconnection transformer switch DL3, interconnection transformer switch DL4 and the sectionalizing switch FDL2 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

[0010] Step S2 further includes: If both sectionalizing switches FDL1 and FDL2 are detected to be in the closed state, the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, the overcurrent protection one-time-limit trips sectionalizing switch FDL1, the overcurrent protection two-time-limit trips tie transformer switch DL3, and the overcurrent protection three-time-limit trips tie transformer switch DL4; or, the overcurrent protection one-time-limit trips sectionalizing switch FDL2, the overcurrent protection two-time-limit trips tie transformer switch DL4, and the overcurrent protection three-time-limit trips tie transformer switch DL3. Based on the determined backup protection tripping logic, the sectionalizing switch FDL1, the interconnecting transformer switch DL3, and the interconnecting transformer switch DL4 are tripped in sequence; or, the sectionalizing switch FDL2, the interconnecting transformer switch DL4, and the interconnecting transformer switch DL3 are tripped in sequence to achieve backup protection for the 10kV and 20kV interconnecting transformers.

[0011] This invention also provides a protection device for a 10kV and 20kV interconnection transformer, comprising: The sectionalizing switch status detection unit is used to detect the opening and closing status of sectionalizing switches FDL1 and FDL2 when there is a fault on the load side of the 10kV and 20kV interconnection transformer. The backup protection logic execution unit is used to select one of three preset backup protection settings based on the detected opening and closing states of sectionalizing switches FDL1 and FDL2, and execute the backup protection tripping logic configured according to the power supply mode and the three-stage overcurrent protection time limit corresponding to the selected backup protection setting. This sequentially drives the corresponding closed sectionalizing switches and tie transformer switches to trip, thereby achieving backup protection for the 10kV and 20kV tie transformers. The power supply mode includes a 10kV distribution network bus single-side power supply mode, a 20kV distribution network bus single-side power supply mode, and a 10kV distribution network bus and 20kV distribution network bus parallel power supply mode. The three-stage overcurrent protection time limit includes overcurrent protection time limit one, overcurrent protection time limit two, and overcurrent protection time limit three.

[0012] The backup protection logic execution unit includes: The backup protection logic execution module under 10kV single-side power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that the sectionalizing switch FDL1 is in the closed state and the sectionalizing switch FDL2 is in the open state. Specifically, under the 10kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL4, the overcurrent protection two time limit trips the tie transformer switch DL3, and the overcurrent protection three time limit trips the sectionalizing switch FDL1. Based on the determined backup protection tripping logic, the interconnection transformer switch DL4, interconnection transformer switch DL3 and the sectionalizing switch FDL1 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

[0013] The backup protection logic execution unit further includes: The backup protection logic execution module under 20kV single-side power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that the sectionalizing switch FDL1 is in the open state and the sectionalizing switch FDL2 is in the closed state. Specifically, under the 20kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL3, the overcurrent protection two time limit trips the tie transformer switch DL4, and the overcurrent protection three time limit trips the sectionalizing switch FDL2. Based on the determined backup protection tripping logic, the interconnection transformer switch DL3, interconnection transformer switch DL4 and the sectionalizing switch FDL2 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

[0014] The backup protection logic execution unit further includes: The backup protection logic execution module under 10kV and 20kV parallel power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that both sectionalizing switches FDL1 and FDL2 are in the closed state. Specifically, under the parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, the overcurrent protection one-time-limit trips sectionalizing switch FDL1, the overcurrent protection two-time-limit trips tie transformer switch DL3, and the overcurrent protection three-time-limit trips tie transformer switch DL4; or, the overcurrent protection one-time-limit trips sectionalizing switch FDL2, the overcurrent protection two-time-limit trips tie transformer switch DL4, and the overcurrent protection three-time-limit trips tie transformer switch DL3. Based on the determined backup protection tripping logic, the sectionalizing switch FDL1, the interconnecting transformer switch DL3, and the interconnecting transformer switch DL4 are tripped in sequence; or, the sectionalizing switch FDL2, the interconnecting transformer switch DL4, and the interconnecting transformer switch DL3 are tripped in sequence to achieve backup protection for the 10kV and 20kV interconnecting transformers.

[0015] Implementing the embodiments of the present invention has the following beneficial effects: In this invention, the protection device for the 10kV and 20kV interconnection transformer is pre-configured with three backup protection settings based on the power supply mode and the three-stage overcurrent protection time limit, corresponding to three backup protection tripping logics. Once a load-side fault occurs in the 10kV and 20kV interconnection transformer, a backup protection setting will be selected based on the opening and closing status of sectionalizing switches FDL1 and FDL2 to execute the corresponding backup protection tripping logic. By sequentially driving the corresponding closed sectionalizing switches and interconnection transformer switches to trip, backup protection for the 10kV and 20kV interconnection transformer is achieved. This not only avoids the problem of cascading tripping of switches on the corresponding power supply side caused by partial sectionalizing switch malfunctions, but also utilizes automatic adaptation of different backup protection settings to trip the corresponding switches in batches, thereby avoiding overcurrent impact on the 10kV and 20kV interconnection transformer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0017] Figure 1 A schematic diagram illustrating the retrofitting of a mixed 10kV and 20kV power supply area in existing technology; Figure 2A flowchart illustrating a method for implementing a protection device for a 10kV and 20kV interconnection transformer, as provided in an embodiment of the present invention; Figure 3 A schematic diagram of the backup protection tripping logic of a 10kV and 20kV interconnection transformer protection device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a protection device for a 10kV and 20kV interconnection transformer provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] like Figure 2 As shown in the figure, a method for implementing a protection device for a 10kV and 20kV interconnection transformer is provided in an embodiment of the present invention. The method includes the following steps: Step S1: When a fault occurs on the load side of the 10kV and 20kV interconnection transformer, check the opening and closing status of sectionalizing switch FDL1 and sectionalizing switch FDL2. The specific process is as follows, based on Figure 1 It can be seen that the protection device for the 10kV and 20kV interconnection transformer is connected to the switch positions of sectionalizing switch FDL1, sectionalizing switch FDL2, interconnection transformer switch DL3 and interconnection transformer switch DL4, and obtains the opening and closing status of each switch in real time and performs status control.

[0020] At this time, if a fault occurs on the load side of the 10kV and 20kV interconnection transformer, the opening and closing status of the sectionalizing switch FDL1 and sectionalizing switch FDL2 at the time of the fault will be automatically detected.

[0021] Step S2: Based on the detected opening and closing states of sectionalizing switches FDL1 and FDL2, select one of the three preset backup protection settings to execute the backup protection tripping logic configured according to the power supply mode and the three-stage overcurrent protection time limit. This sequentially drives the corresponding closed sectionalizing switches and tie transformer switches to trip, thereby achieving backup protection for the 10kV and 20kV tie transformers. The power supply mode includes a 10kV distribution network bus single-side power supply mode, a 20kV distribution network bus single-side power supply mode, and a 10kV distribution network bus and 20kV distribution network bus parallel power supply mode. The three-stage overcurrent protection time limit includes overcurrent protection time limit one, overcurrent protection time limit two, and overcurrent protection time limit three.

[0022] The specific process is as follows: the protection device for the 10kV and 20kV interconnection transformer will first configure three backup protection tripping logics according to the power supply mode on the power supply side and the three-stage time limit of overcurrent protection, and configure corresponding backup protection settings on the device to correspond to the three backup protection tripping logics so as to start execution.

[0023] At this time, given that the power supply modes on the power supply side include single-side power supply mode of 10kV distribution network bus, single-side power supply mode of 20kV distribution network bus, and parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, and that the overcurrent protection has three time limits, including the overcurrent protection one-time limit T used to coordinate with the outgoing line instantaneous overcurrent protection, GL1 (e.g., 0.2s~0.5s), overcurrent protection with two-time delay (T) used in conjunction with outgoing line overcurrent protection. GL2 (T) GL2 =T GL1 +Δt1 (e.g., 0.6s~0.9s) and overcurrent protection with three time limits T GL3 (T) GL3 =T GL2 +Δt2, such as >0.9s) corresponds to the three backup protection tripping logics configured.

[0024] like Figure 3 As shown, the specific tripping logics for the three backup protection methods described above are as follows: (1) In the 10kV distribution network bus single-side power supply mode, since the sectionalizing switch FDL1, the tie transformer switch DL3 and the tie transformer switch DL4 are all closed, the overcurrent protection one time limit trips the tie transformer switch DL4, the overcurrent protection two time limit trips the tie transformer switch DL3 and the overcurrent protection three time limit trips the sectionalizing switch FDL1 from the tripping angle of the 10kV distribution network bus side; (2) In the single-side power supply mode of the 20kV distribution network bus, since the sectionalizing switch FDL2, the tie transformer switch DL3 and the tie transformer switch DL4 are all closed, the overcurrent protection one time limit trips the tie transformer switch DL3, the overcurrent protection two time limit trips the tie transformer switch DL4 and the overcurrent protection three time limit trips the sectionalizing switch FDL2 from the tripping angle of the 20kV distribution network bus side. (3) In the parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, since the sectionalizing switch FDL1, sectionalizing switch FDL2, tie transformer switch DL3 and tie transformer switch DL4 are all closed, the overcurrent protection one-time time limit tripping of sectionalizing switch FDL1, the overcurrent protection two-time time limit tripping of tie transformer switch DL3 and the overcurrent protection three-time time limit tripping of tie transformer switch DL4 are set from the tripping angle of 10kV distribution network bus side; the overcurrent protection one-time time limit tripping of sectionalizing switch FDL2, the overcurrent protection two-time time limit tripping of tie transformer switch DL4 and the overcurrent protection three-time time limit tripping of tie transformer switch DL3 are set from the tripping angle of 20kV distribution network bus side.

[0025] Therefore, step S2 specifically includes: If it is detected that sectionalizing switch FDL1 is in the closed state and sectionalizing switch FDL2 is in the open state, the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the single-side power supply mode of the 10kV distribution network bus, the overcurrent protection one-time-limit trips the tie transformer switch DL4, the overcurrent protection two-time-limit trips the tie transformer switch DL3, and the overcurrent protection three-time-limit trips the sectionalizing switch FDL1. According to the determined backup protection tripping logic, the tie transformer switch DL4, the tie transformer switch DL3, and the sectionalizing switch FDL1 are driven to trip in sequence to realize the backup protection for the 10kV and 20kV tie transformers.

[0026] If it is detected that the sectionalizing switch FDL1 is in the open state and the sectionalizing switch FDL2 is in the closed state, the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the single-side power supply mode of the 20kV distribution network bus, the overcurrent protection one time-limit trips the tie transformer switch DL3, the overcurrent protection two time-limit trips the tie transformer switch DL4, and the overcurrent protection three time-limit trips the sectionalizing switch FDL2. According to the determined backup protection tripping logic, the tie transformer switch DL3, the tie transformer switch DL4, and the sectionalizing switch FDL2 are driven to trip in sequence to realize the backup protection for the 10kV and 20kV tie transformers.

[0027] If both sectionalizing switches FDL1 and FDL2 are detected to be in the closed state, the backup protection tripping logic corresponding to the selected backup protection setting from the three backup protection settings is determined. Specifically, under the parallel power supply mode of the 10kV distribution network bus and the 20kV distribution network bus, the overcurrent protection one-time-limit trip sectionalizing switch FDL1, the overcurrent protection two-time-limit trip tie transformer switch DL3, and the overcurrent protection three-time-limit trip tie transformer switch DL4; or, the overcurrent protection one-time-limit trip sectionalizing switch FDL2, the overcurrent protection two-time-limit trip tie transformer switch DL4, and the overcurrent protection three-time-limit trip tie transformer switch DL3; according to the determined backup protection tripping logic, the sectionalizing switch FDL1, the tie transformer switch DL3, and the tie transformer switch DL4 are driven to trip in sequence; or, the sectionalizing switch FDL2, the tie transformer switch DL4, and the tie transformer switch DL3 are driven to trip in sequence, thereby realizing backup protection for the 10kV and 20kV tie transformers.

[0028] like Figure 4 As shown in the figure, a protection device for a 10kV and 20kV interconnection transformer is provided in an embodiment of the present invention, comprising: The sectionalizing switch status detection unit 110 is used to detect the opening and closing status of sectionalizing switches FDL1 and FDL2 when there is a fault on the load side of the 10kV and 20kV interconnection transformer. The backup protection logic execution unit 120 is used to select one of three preset backup protection settings based on the detected opening and closing states of sectionalizing switches FDL1 and FDL2, and execute the backup protection tripping logic configured according to the power supply mode and the three-stage overcurrent protection time limit corresponding to the selected backup protection setting. This sequentially drives the corresponding closed sectionalizing switches and tie transformer switches to trip, thereby achieving backup protection for the 10kV and 20kV tie transformers. The power supply mode includes a 10kV distribution network bus single-side power supply mode, a 20kV distribution network bus single-side power supply mode, and a 10kV distribution network bus and 20kV distribution network bus parallel power supply mode. The three-stage overcurrent protection time limit includes overcurrent protection time limit one, overcurrent protection time limit two, and overcurrent protection time limit three.

[0029] The backup protection logic execution unit 120 includes: The backup protection logic execution module under 10kV single-side power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that the sectionalizing switch FDL1 is in the closed state and the sectionalizing switch FDL2 is in the open state. Specifically, under the 10kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL4, the overcurrent protection two time limit trips the tie transformer switch DL3, and the overcurrent protection three time limit trips the sectionalizing switch FDL1. Based on the determined backup protection tripping logic, the interconnection transformer switch DL4, interconnection transformer switch DL3 and the sectionalizing switch FDL1 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

[0030] The backup protection logic execution unit 120 further includes: The backup protection logic execution module under 20kV single-side power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that the sectionalizing switch FDL1 is in the open state and the sectionalizing switch FDL2 is in the closed state. Specifically, under the 20kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL3, the overcurrent protection two time limit trips the tie transformer switch DL4, and the overcurrent protection three time limit trips the sectionalizing switch FDL2. Based on the determined backup protection tripping logic, the interconnection transformer switch DL3, interconnection transformer switch DL4 and the sectionalizing switch FDL2 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

[0031] The backup protection logic execution unit 120 further includes: The backup protection logic execution module under 10kV and 20kV parallel power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that both sectionalizing switches FDL1 and FDL2 are in the closed state. Specifically, under the parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, the overcurrent protection one-time-limit trips sectionalizing switch FDL1, the overcurrent protection two-time-limit trips tie transformer switch DL3, and the overcurrent protection three-time-limit trips tie transformer switch DL4; or, the overcurrent protection one-time-limit trips sectionalizing switch FDL2, the overcurrent protection two-time-limit trips tie transformer switch DL4, and the overcurrent protection three-time-limit trips tie transformer switch DL3. Based on the determined backup protection tripping logic, the sectionalizing switch FDL1, the interconnecting transformer switch DL3, and the interconnecting transformer switch DL4 are tripped in sequence; or, the sectionalizing switch FDL2, the interconnecting transformer switch DL4, and the interconnecting transformer switch DL3 are tripped in sequence to achieve backup protection for the 10kV and 20kV interconnecting transformers.

[0032] Implementing the embodiments of the present invention has the following beneficial effects: In this invention, the protection device for the 10kV and 20kV interconnection transformer is pre-configured with three backup protection settings based on the power supply mode and the three-stage overcurrent protection time limit, corresponding to three backup protection tripping logics. Once a load-side fault occurs in the 10kV and 20kV interconnection transformer, a backup protection setting will be selected based on the opening and closing status of sectionalizing switches FDL1 and FDL2 to execute the corresponding backup protection tripping logic. By sequentially driving the corresponding closed sectionalizing switches and interconnection transformer switches to trip, backup protection for the 10kV and 20kV interconnection transformer is achieved. This not only avoids the problem of cascading tripping of switches on the corresponding power supply side caused by partial sectionalizing switch malfunctions, but also utilizes automatic adaptation of different backup protection settings to trip the corresponding switches in batches, thereby avoiding overcurrent impact on the 10kV and 20kV interconnection transformer.

[0033] It is worth noting that in the above-described device system embodiments, the various device modules are divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional module are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0034] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, optical disk, etc.

[0035] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for implementing a protection device for a 10kV and 20kV interconnection transformer, characterized in that, The method includes the following steps: S1. When a fault occurs on the load side of the 10kV and 20kV interconnection transformer, check the opening and closing status of sectionalizing switch FDL1 and sectionalizing switch FDL2. S2. Based on the detected opening and closing states of sectionalizing switches FDL1 and FDL2, select one of the three preset backup protection settings to execute the backup protection tripping logic configured according to the power supply mode and the three-stage overcurrent protection time limit. This sequentially drives the corresponding closed sectionalizing switches and tie transformer switches to trip, thereby achieving backup protection for the 10kV and 20kV tie transformers. The power supply mode includes a 10kV distribution network bus single-side power supply mode, a 20kV distribution network bus single-side power supply mode, and a 10kV distribution network bus and 20kV distribution network bus parallel power supply mode. The three-stage overcurrent protection time limit includes overcurrent protection time limit one, overcurrent protection time limit two, and overcurrent protection time limit three.

2. The method for implementing the 10kV and 20kV interconnection transformer protection device as described in claim 1, characterized in that, Step S2 specifically includes: If it is detected that the sectionalizing switch FDL1 is in the closed state and the sectionalizing switch FDL2 is in the open state, then the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the 10kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL4, the overcurrent protection two time limit trips the tie transformer switch DL3, and the overcurrent protection three time limit trips the sectionalizing switch FDL1. Based on the determined backup protection tripping logic, the interconnection transformer switch DL4, interconnection transformer switch DL3 and the sectionalizing switch FDL1 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

3. The method for implementing the 10kV and 20kV interconnection transformer protection device as described in claim 2, characterized in that, Step S2 further includes: If it is detected that the sectionalizing switch FDL1 is in the open state and the sectionalizing switch FDL2 is in the closed state, then the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the single-side power supply mode of the 20kV distribution network bus, the overcurrent protection one time limit trips the tie transformer switch DL3, the overcurrent protection two time limit trips the tie transformer switch DL4, and the overcurrent protection three time limit trips the sectionalizing switch FDL2. Based on the determined backup protection tripping logic, the interconnection transformer switch DL3, interconnection transformer switch DL4 and the sectionalizing switch FDL2 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

4. The method for implementing the 10kV and 20kV interconnection transformer protection device as described in claim 3, characterized in that, Step S2 further includes: If both sectionalizing switches FDL1 and FDL2 are detected to be in the closed state, the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings is determined. Specifically, under the parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, the overcurrent protection one-time-limit trips sectionalizing switch FDL1, the overcurrent protection two-time-limit trips tie transformer switch DL3, and the overcurrent protection three-time-limit trips tie transformer switch DL4; or, the overcurrent protection one-time-limit trips sectionalizing switch FDL2, the overcurrent protection two-time-limit trips tie transformer switch DL4, and the overcurrent protection three-time-limit trips tie transformer switch DL3. Based on the determined backup protection tripping logic, the sectionalizing switch FDL1, the interconnecting transformer switch DL3, and the interconnecting transformer switch DL4 are tripped in sequence; or, the sectionalizing switch FDL2, the interconnecting transformer switch DL4, and the interconnecting transformer switch DL3 are tripped in sequence to achieve backup protection for the 10kV and 20kV interconnecting transformers.

5. A protection device for a 10kV and 20kV interconnection transformer, characterized in that, include: The sectionalizing switch status detection unit is used to detect the opening and closing status of sectionalizing switches FDL1 and FDL2 when there is a fault on the load side of the 10kV and 20kV interconnection transformer. The backup protection logic execution unit is used to select one of three preset backup protection settings based on the detected opening and closing states of sectionalizing switches FDL1 and FDL2, and execute the backup protection tripping logic configured according to the power supply mode and the three-stage overcurrent protection time limit corresponding to the selected backup protection setting. This sequentially drives the corresponding closed sectionalizing switches and tie transformer switches to trip, thereby achieving backup protection for the 10kV and 20kV tie transformers. The power supply mode includes a 10kV distribution network bus single-side power supply mode, a 20kV distribution network bus single-side power supply mode, and a 10kV distribution network bus and 20kV distribution network bus parallel power supply mode. The three-stage overcurrent protection time limit includes overcurrent protection time limit one, overcurrent protection time limit two, and overcurrent protection time limit three.

6. The 10kV and 20kV interconnection transformer protection device as described in claim 5, characterized in that, The backup protection logic execution unit includes: The backup protection logic execution module under 10kV single-side power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that the sectionalizing switch FDL1 is in the closed state and the sectionalizing switch FDL2 is in the open state. Specifically, under the 10kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL4, the overcurrent protection two time limit trips the tie transformer switch DL3, and the overcurrent protection three time limit trips the sectionalizing switch FDL1. Based on the determined backup protection tripping logic, the interconnection transformer switch DL4, interconnection transformer switch DL3 and the sectionalizing switch FDL1 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

7. The 10kV and 20kV interconnection transformer protection device as described in claim 6, characterized in that, The backup protection logic execution unit further includes: The backup protection logic execution module under 20kV single-side power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that the sectionalizing switch FDL1 is in the open state and the sectionalizing switch FDL2 is in the closed state. Specifically, under the 20kV distribution network bus single-side power supply mode, the overcurrent protection one time limit trips the tie transformer switch DL3, the overcurrent protection two time limit trips the tie transformer switch DL4, and the overcurrent protection three time limit trips the sectionalizing switch FDL2. Based on the determined backup protection tripping logic, the interconnection transformer switch DL3, interconnection transformer switch DL4 and the sectionalizing switch FDL2 are sequentially driven to trip, thereby realizing backup protection for the 10kV and 20kV interconnection transformers.

8. The 10kV and 20kV interconnection transformer protection device as described in claim 7, characterized in that, The backup protection logic execution unit further includes: The backup protection logic execution module under 10kV and 20kV parallel power supply is used to determine the backup protection tripping logic corresponding to the backup protection setting selected from the three backup protection settings if it is detected that both sectionalizing switches FDL1 and FDL2 are in the closed state. Specifically, under the parallel power supply mode of 10kV distribution network bus and 20kV distribution network bus, the overcurrent protection one-time-limit trips sectionalizing switch FDL1, the overcurrent protection two-time-limit trips tie transformer switch DL3, and the overcurrent protection three-time-limit trips tie transformer switch DL4; or, the overcurrent protection one-time-limit trips sectionalizing switch FDL2, the overcurrent protection two-time-limit trips tie transformer switch DL4, and the overcurrent protection three-time-limit trips tie transformer switch DL3. Based on the determined backup protection tripping logic, the sectionalizing switch FDL1, the interconnecting transformer switch DL3, and the interconnecting transformer switch DL4 are tripped in sequence; or, the sectionalizing switch FDL2, the interconnecting transformer switch DL4, and the interconnecting transformer switch DL3 are tripped in sequence to achieve backup protection for the 10kV and 20kV interconnecting transformers.

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