An adaptive feeder automation algorithm for hybrid grid

Abstract

The present invention discloses a hybrid grid adaptive feeder automation algorithm, which relates to the technical field of distribution grid fault processing, step 1: confirm the switch operation state; step 2: select the feeder automation algorithm according to different scenarios; step 3: if the line fails when the traditional line is open-loop operated, the overcurrent fault logic directly cuts off the upstream switch of the fault point; step 4: if the traditional line fails when connected to the photovoltaic grid or wind power, the upstream and downstream switches of the fault point will have overcurrent fault characteristics, and the judgment is made according to the overcurrent direction criterion, and the fault is cut off and isolated. The beneficial effect of the present invention is that when the traditional line undergoes grid transformation and new energy is connected to the grid, there is no need to re-debug the protection function of the line distribution and use device, or modify the parameter setting value. The device can actively sense the grid operation state and memorize it when the line fails, and automatically implement the corresponding protection function configuration to ensure stable and reliable operation of the line.

Description

Technical Field

[0001] The present invention relates to the technical field of power communication protocol development process control, and in particular to a hybrid grid adaptive feeder automation algorithm. Background Art

[0002] With the development of new energy sources such as distributed energy and photovoltaic grid connection, the original open-loop grid has gradually added new energy to form an open-loop and closed-loop hybrid grid that operates simultaneously. This type of operation system has gradually become an important part of distribution network automation. The intervention of new energy has led to changes in the operation mode of the power grid. Conventional protection functions cannot automatically switch to functions that meet the fault isolation requirements of such hybrid grids. If manually removed, the hybrid grid line fault isolation time is long, the system impact is large, and the equipment life is also short. In addition, due to the different fault characteristics of closed-loop operation and open-loop operation on the same line, it is necessary to formulate a separate response switch. The hybrid grid switch equipped with a feeder adaptive algorithm can quickly remove the fault area and quickly restore power supply, which is of great significance to reducing the outage area, shortening the outage time, and improving power supply reliability. Summary of the invention

[0003] The object of the present invention is to provide a hybrid grid adaptive feeder automation algorithm to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a hybrid grid adaptive feeder automation algorithm, comprising the following steps:

[0005] Step 1: Confirm the switch operation status;

[0006] Step 2: Select feeder automation algorithm according to different scenarios;

[0007] Step 3: If a fault occurs in the line during open-loop operation of the traditional line, the overcurrent fault logic directly cuts off the switch upstream of the fault point;

[0008] Step 4: If a fault occurs when the traditional line is connected to the photovoltaic grid or wind power, the upstream and downstream switches of the fault point will have overcurrent fault characteristics. The fault will be judged based on the overcurrent direction criterion, and the fault will be removed and isolated.

[0009] Further, based on step 3, the downstream switch can be disconnected by undervoltage tripping through fault isolation logic.

[0010] Furthermore, based on the switches upstream of the fault point in step 4, the overcurrent directions are all within the zone, and the overcurrent directions downstream of the fault point are all outside the zone.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. The hybrid grid adaptive feeder automation algorithm does not need to re-debug the protection function of the line power distribution device or modify the parameter setting when the traditional line is transformed and the new energy is connected to the grid. The device can actively sense the grid operation status when a line fault occurs and memorize it until the fault processing is completed, and automatically implement the corresponding protection function configuration to ensure stable and reliable operation of the line. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of a conventional open-loop operation grid of a distribution network of the present invention;

[0014] Figure 2 A schematic diagram of a hybrid grid connected to the new energy CB03 of the present invention;

[0015] Figure 3 It is a schematic diagram of the fault point of the present invention in the open loop operation CB01;

[0016] Figure 4 It is a schematic diagram of the fault point of the present invention in the closed loop operation CB02-CB03;

[0017] Figure 5 It is a schematic diagram of a distributed self-healing single-contact model of the present invention;

[0018] Figure 6 It is a logical schematic diagram of the adaptive feeder algorithm of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only 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.

[0020] A hybrid grid adaptive feeder automation algorithm, the present invention provides the following technical solutions:

[0021] like Figure 3 When a short circuit fault occurs between the section switches F02 and F03 on line 01, F02 triggers a "node fault" signal and sends it to the switches F01 and F03 on both sides, and only one side of F02 and F03 has a "node fault signal". At this time, devices F02 and F03 can determine that the line is in an open-loop operation state based on this feature, and the device automatically performs open-loop fault isolation judgment logic, and the device can forward the switch operation status to other switches F01 and F04 on this line, so that they all perform protection judgment according to the open-loop logic during this fault handling process.

[0022] like Figure 4When a short circuit fault occurs between the section switches F05 and F06 on the closed-loop lines 02 and 03, F05, F06, F07, F08, and F09 will all trigger a "node fault" signal and send it to both sides. At this time, both sides of the section switches F05, F06, and F08 will receive the "node fault" signal. At this time, the device can determine that this line is in a closed-loop operation state based on this feature and forward it to other switches on the same line. At this time, during this fault handling process, the closed-loop lines 02 and 03 can automatically switch to the closed-loop fault isolation judgment logic and perform fault isolation.

[0023] like Figure 5 As shown, the action logic of "fault isolation" in open-loop operation is: 1: There is a fault in the line, and one side of M and N has no fault (M1&M2&M3=0 or N1&N2&N3=0); 2: There is no fault in the line, and only one contact has a fault: num(M1=1, M2=1, M3=1, N1=1, N2=1, N3=1)=1; The action logic of "fault isolation" in closed-loop operation is: 1: There is a fault in the line, and one side of M and N has "overcurrent direction blocking" (M1&M2&M3=0 or N1&N2&N3=0); 2: "Overcurrent direction blocking" in the line, and only one contact has an overcurrent fault: num(M1=1, M2=1, M3=1, N1=1, N2=1, N3=1)=1;

[0024] like Figure 6 The figure shows a simplified flow chart of the device identifying faults, determining the open-loop and closed-loop operation status of the line switch, cutting off and isolating the faulty area, and restoring power supply: After the device is put into the feeder automation function, in the case of abnormal communication, the backup protection function is directly started. When the communication is normal, the closed-loop processing logic is used by default. When a line fault occurs, if the open-loop fault characteristics are sensed, the signal "open-loop operation" is forwarded to other switches on the line and memorized for a period of time. During the memory time, the fault is processed according to the fault isolation logic of open-loop operation. The remaining rejection logic and power supply recovery logic are consistent in the case of open-loop and hybrid grid operation.

[0025] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A hybrid grid adaptive feeder automation algorithm comprising the following steps: Step 1: Confirm the switch operation status. When a short circuit fault occurs between the section switches F02 and F03 on line 01, F02 triggers a "node fault" signal and sends it to the switches F01 and F03 on both sides. F02 and F03 have a "node fault signal" on one and only one side. At this time, devices F02 and F03 can determine that this line is in an open-loop operation state based on this feature. The device automatically performs open-loop fault isolation judgment logic, and the device can forward the switch operation status to other switches F01 and F04 on this line, so that they can perform protection judgment according to the open-loop logic during this fault handling process; Step 2: Select feeder automation algorithm according to different scenarios; Step 3: If a fault occurs in the line during open-loop operation of the traditional line, the overcurrent fault logic directly cuts off the switch upstream of the fault point; Step 4: If a fault occurs when a traditional line is connected to a photovoltaic grid or wind power, the upstream and downstream switches of the fault point will have overcurrent fault characteristics. The fault will be judged according to the overcurrent direction criterion, and the fault will be removed and isolated. When a short circuit fault occurs between the segment switches F05 and F06 on the closed-loop line 02 and line 03, F05, F06, F07, F08, and F09 will trigger a "node fault" signal and send it to both sides. At this time, both sides of the segment switches F05, F06, and F08 will receive the "node fault" signal. At this time, the device can judge that this line is in a closed-loop operation state based on this feature and forward it to other switches on the same line. At this time, during this fault handling process, the closed-loop line 02 and line 03 can automatically switch to the closed-loop fault isolation judgment logic and perform fault isolation.

2. A hybrid grid adaptive feeder automation algorithm according to claim 1, characterized in that: Based on step 3, the downstream switch is disconnected by undervoltage tripping through the fault isolation logic.

3. The hybrid grid adaptive feeder automation algorithm according to claim 1, characterized in that: Based on the switch upstream of the fault point described in step 4, the overcurrent direction is within the zone, and the overcurrent direction downstream of the fault point is outside the zone.

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