A secondary backbone network distribution network structure and its distributed self-healing system and self-healing method

Abstract

The embodiment of the present invention relates to the technical field of distribution network line fault maintenance, and discloses a secondary main network distribution network structure and its distributed self-healing system and self-healing method. The above-mentioned secondary main network distribution network structure is characterized in that it includes a first distribution network structure, the first distribution network structure includes a first power supply to a second power supply, a first switch to a second switch, and a first distribution unit to a second distribution unit; the first distribution unit is a single busbar segmented wiring method, the upper-level power supplies of the first busbar and the second busbar come from the first power supply and the second power supply respectively, the first power supply is connected to the first busbar of the first distribution unit, the second power supply is connected to the second busbar of the first distribution unit, and the first distribution unit is powered by dual power supplies; the second distribution unit is a single busbar segmented wiring method, cascaded to the first distribution unit, the third busbar is connected to the first busbar, the fourth busbar is connected to the second busbar, and the second distribution unit is powered by dual power supplies.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network line fault maintenance, and in particular to a secondary trunk network distribution network structure and a distributed self-healing system and a self-healing method thereof. Background Art

[0002] As urban load centers have increasingly higher requirements for power supply reliability, distribution network structures have become increasingly complex, and the demand for self-healing technology for high-reliability distribution network structures has also increased. In recent years, various high-reliability distribution network structures such as double petal type and double ring network have been effectively applied to important loads in urban centers, improving the reliability of power supply. However, for the ring network structure of multiple switch stations or distribution rooms, the intelligent distributed terminal STU of each switch station or distribution room must be put into operation synchronously to ensure the normal operation of the entire self-healing system. In the early stage of regional distribution network construction, due to the special requirements of planning and load, each switch station or distribution room often cannot meet the conditions for synchronous operation, which brings difficulties to the normal operation of the self-healing system and distributed STU.

[0003] At present, the research on distribution network structure and its self-healing methods has not considered the transitional solutions that can meet the system operation mode requirements in the early stage of distribution network planning and construction. The self-healing devices and systems used in actual projects often play a role only after all switch stations and distribution rooms in the entire area are put into operation. This greatly limits the important protection role of the self-healing system in the secondary trunk network of the distribution network, and has an adverse impact on improving the reliability of distribution network power supply. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a secondary backbone network distribution network structure and a distributed self-healing system and a self-healing method thereof, so as to achieve effective self-healing protection when a secondary backbone network line fails during the distribution network construction period.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] In a first aspect, an embodiment of the present invention provides a secondary mains distribution network structure, including a first distribution network structure, wherein the first distribution network structure includes a first power supply to a second power supply, a first switch to a second switch, and a first distribution unit to a second distribution unit; the first distribution unit is a single busbar segmented wiring method, the first power supply is connected to the first busbar of the first distribution unit, and the second power supply is connected to the second busbar of the first distribution unit, so as to realize dual power supply of the first distribution unit; the second distribution unit is a single busbar segmented wiring method, cascaded to the first distribution unit, the third busbar is connected to the first busbar, and the fourth busbar is connected to the second busbar, so as to realize dual power supply of the second distribution unit

[0007] Based on the first aspect, in some embodiments, the first power distribution unit includes a first bus to a second bus, a third switch to a sixth switch, and a first section contact switch; the first power supply is connected to the first bus through the first switch and the third switch, the second power supply is connected to the second bus through the second switch and the fourth switch, and the first bus and the second bus are connected through the first section contact switch; the second power distribution unit includes a third bus to a fourth bus, a seventh switch to an eighth switch, and a second section contact switch; one end of the seventh switch is connected to the fifth switch and the other end is connected to the third bus, one end of the eighth switch is connected to the sixth switch and the other end is connected to the fourth bus, and the third bus and the fourth bus are connected through the second section contact switch. The first power supply is connected to the first switch, the third switch, the fifth switch and the seventh switch in sequence, and the second power supply is connected to the second switch, the fourth switch, the sixth switch and the eighth switch in sequence, forming the main supply circuit of the first distribution network structure.

[0008] Based on the first aspect, in some embodiments, the secondary main network distribution network structure also includes a second distribution network structure, the second distribution network structure includes a first power supply to a second power supply, a first switch to a second switch, and a first distribution unit to a third distribution unit; the second distribution unit also includes a tenth switch and an eleventh switch, the tenth switch is connected to the third bus, and the eleventh switch is connected to the fourth bus; the third distribution unit includes a fifth bus to a sixth bus, a twelfth switch to a thirteenth switch, and a third section connecting switch; one end of the twelfth switch is connected to the third bus through the tenth switch, and the other end is connected to the fifth bus, one end of the thirteenth switch is connected to the fourth bus through the eleventh switch, and the other end is connected to the sixth bus, and the fifth bus and the sixth bus are connected through the third section connecting switch.

[0009] In the second aspect, an embodiment of the present invention provides a distributed self-healing system of a secondary backbone distribution network structure, characterized in that it is applicable to the secondary backbone distribution network structure as described in the first aspect above, and the distributed self-healing system includes an intelligent distributed terminal STU, a switch and an external protection device; the STU is used to collect electrical quantity information and position information at each switch, and control the switch action based on a preset action logic; the STU is configured according to the bus position, and each bus section of each distribution unit is configured with an STU, and adjacent STUs are connected by optical fiber to achieve mutual communication; the external protection device is installed at each switch on the main supply circuit of the secondary backbone distribution network structure, and is used to control the action of each switch.

[0010] Based on the second aspect, in some embodiments, when a fault occurs in the distribution network, the STU can achieve at least one of the following functions: fault location, fault isolation and power supply restoration in non-fault areas; the fault location function includes active location and passive location; the fault isolation function includes at least one of no-voltage tripping, line fault isolation, busbar fault isolation, feeder line fault isolation, failure protection, remote tripping and small power supply joint cutting functions; the power supply restoration function in non-fault areas includes a single-ring network self-healing function and a segmented backup automatic switching function.

[0011] In the third aspect, an embodiment of the present invention provides a self-healing method for a distributed self-healing system of a secondary backbone distribution network structure, characterized in that it is applicable to a distributed self-healing system of a secondary backbone distribution network structure as described in the second aspect, and the method includes: obtaining fault location information through a fault location function; controlling the action of corresponding switch nodes according to the fault location information and the preset action logic of the distributed self-healing system to achieve fault isolation; controlling the action of corresponding switch nodes according to the fault location information and the preset action logic of the distributed self-healing system to restore normal power supply to the secondary backbone network.

[0012] Based on the third aspect, in some embodiments, the fault location information is obtained through the fault location function, including: STU obtains the action signal of the external protection device, and determines the fault location through the action signal of the external protection device; when the external protection device action signal is not received, the internal fault location element information is used to determine the fault location; if the external protection device action signal and the internal fault location element information are received at the same time, and the fault locations determined according to the external protection device action signal and the internal fault location element information are inconsistent, the fault location result determined according to the external protection device action signal is used.

[0013] Based on the third aspect, in some embodiments, the corresponding switch node action is controlled according to the fault location information and the preset action logic of the distributed self-healing system to achieve fault isolation, including: defining the lines and switches from the third switch to the eighth switch and from the first section connecting switch to the second section connecting switch as inside the ring, and defining the lines from the first power supply to the second power supply, from the first switch to the second switch, and between the first switch and the third switch, and between the second switch and the fourth switch as outside the ring; applying the no-voltage tripping function to achieve fault isolation; the application of the no-voltage tripping function to achieve fault isolation includes: if the fault location information indicates that the line or switch outside the ring has a fault, the switch directly connected to the switch station on the side of the fault power outage on both sides of the open ring point is tripped, and the no-voltage tripping function is activated to perform fault isolation; if the fault location information indicates that the line or switch inside the ring has a fault, current discrimination is performed through the switch directly connected to the switch station. If a large reverse current flows through the switch directly connected to the switch station, it is determined that a fault has occurred in the ring network, and the no-voltage tripping function is locked.

[0014] Based on the third aspect, in some embodiments, according to the fault location information and the preset action logic of the distributed self-healing system, the distributed self-healing system operates to control the corresponding switch node actions to restore normal power supply to the secondary backbone network, including: confirming that the fault has been successfully isolated, giving priority to using the single-ring network self-healing function to restore power supply, and the STU sends a closing command to the open-loop point switch to restore power supply to the non-fault area; the open-loop point is the segmented interconnecting switch of the last-level distribution unit; after the single-ring network self-healing function is used to self-heal the open-loop point switch or when the single-ring network self-healing function startup conditions are not met, the segmented standby automatic transfer function is used to restore power supply, and no information exchange is performed between the distribution units at all levels. After the incoming line switch interval or the outgoing line switch interval within the ring is tripped, the segmented interconnecting switch in the distribution unit is closed.

[0015] Based on the third aspect, in some embodiments, the tripping of the incoming line switch interval or the outgoing line switch interval within the ring also includes: determining whether the incoming line switch interval or the outgoing line switch interval within the ring is controlled by the segmented standby automatic re-entry function according to the preset pressure plate activation status on the STU; when the "standby automatic re-entry exits the first interval" pressure plate is activated, the first interval switch is not controlled by the standby automatic re-entry function; when the "standby automatic re-entry exits the first interval" pressure plate is not activated, the first interval switch is controlled by the standby automatic re-entry function; the first interval is any incoming line switch interval or outgoing line switch interval within the ring.

[0016] The secondary trunk network distribution network structure proposed in the embodiment of the present invention is suitable for transition in the initial stage of regional distribution network commissioning, as a beneficial extension and supplement to the main network series, to provide reliable power supply for regional users. The above distribution network structure has great flexibility and scalability, and can be expanded into a double-ring network structure or a multi-cascade access structure according to the planning or load center requirements. At the same time, a corresponding self-healing system and an applicable self-healing method are proposed for the secondary trunk network distribution network structure to achieve effective self-healing protection when the secondary trunk network line fails during the distribution network construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A structural diagram of the first distribution network of the secondary backbone network provided by an embodiment of the present invention;

[0019] Figure 2 A diagram of an expandable dual-ring network structure provided by an embodiment of the present invention;

[0020] Figure 3 A structural diagram of the second distribution network of the secondary backbone network provided by an embodiment of the present invention;

[0021] Figure 4 A configuration diagram of a distributed self-healing system for a secondary backbone network distribution structure provided by an embodiment of the present invention;

[0022] Figure 5 A flow chart of a distributed self-healing system method provided by an embodiment of the present invention;

[0023] Figure 6 A schematic diagram of a secondary backbone network distribution network structure failure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described more clearly below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the effects of the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0026] The secondary backbone network, as a secondary network of the main backbone network, is a network structure with the distribution room as the core node, and is composed of connecting lines between the switch station power supply and the distribution room, and between distribution rooms. Figure 1 The diagram of the secondary backbone network distribution network structure provided by an embodiment of the present invention is shown, which is a single-ring network dual-access cascade secondary backbone network distribution network structure. "Dual access cascade" refers to the access of two-level distribution rooms, and the connection relationship between the two-level distribution rooms is cascade. In the embodiment of the present invention, A and B are two-level distribution rooms respectively.

[0027] The first-level A distribution room adopts a single bus segmented wiring method, and the upper-level power supply of each bus segment comes from two different switch station buses: the first power supply S1 is connected to the first bus A1 of the A distribution room, and the second power supply S2 is connected to the second bus A2 of the A distribution room, realizing dual power supply for the A distribution room.

[0028] The second-level B distribution room also adopts a single busbar segmented wiring method. The two power supplies of the second-level B distribution room come from the two busbars of the upper-level distribution room. Two interconnecting lines are set up to be cascaded to the A distribution room. The first busbar A1 is connected to the third busbar B1, and the second busbar A2 is connected to the fourth busbar B2. In this way, the B distribution room is powered by dual power supplies from the upper-level A distribution room.

[0029] The main wiring of the distribution room is single busbar segmentation, 501 and 502 are the segmented contact switches of the A and B distribution rooms respectively. Switches 101-102-103-104 and 201-202-203-204 constitute the main supply circuit of the single ring network. The outgoing line interval on the busbar of each distribution room in the figure is only a schematic diagram, with 1-2 load lines, such as 601 and 602 intervals.

[0030] like Figure 1 As shown, the secondary backbone network distribution network structure includes a first distribution network structure, and the first distribution network structure includes a first power source S1 to a second power source S2, a first switch 101 to a second switch 201, and a first distribution unit to a second distribution unit.

[0031] The first power distribution unit includes the first busbar A1 to the second busbar A2, the third switch 102 to the sixth switch 203, and the first section contact switch 501. The first power source S1 is connected to the first busbar A1 through the first switch 101 and the third switch 102, the second power source S2 is connected to the second busbar A2 through the second switch 201 and the fourth switch 202, and the first busbar A1 and the second busbar A2 are connected through the first section contact switch 501.

[0032] The second power distribution unit includes the third busbar B1 to the fourth busbar B2, the seventh switch 104 to the eighth switch 204, and the second section contact switch. One end of the seventh switch 104 is connected to the fifth switch 103, and the other end is connected to the third busbar B1, one end of the eighth switch 204 is connected to the sixth switch 203, and the other end is connected to the fourth busbar B2, and the third busbar B1 is connected to the fourth busbar B2 through the second section contact switch 502.

[0033] Exemplarily, the first distribution network structure further includes a ninth switch 601 and a first small power source 602, wherein the ninth switch 601 is connected to the first bus A1, and the first small power source 602 is connected to the third bus B1. The ninth switch and the small power source may also be connected to other buses of the first distribution network structure. Figure 1 The connections shown are for illustration purposes only.

[0034] The first power source S1 is connected to the first switch 101, the third switch 102, the fifth switch 103 and the seventh switch 104 in sequence, and the second power source S2 is connected to the second switch 201, the fourth switch 202, the sixth switch 203 and the eighth switch 204 in sequence, forming the main supply circuit of the first distribution network structure.

[0035] like Figure 2 As shown, the dual-access cascade secondary trunk network distribution network structure is simple and can meet the needs of regional high-reliability power supply in the early stage of regional distribution network planning. As the network gradually expands, it can also be expanded into a double-ring network structure. On the basis of the original grid structure, it is expanded into a double-ring network structure consisting of 4 power supplies from S1 to S4 and 4 distribution rooms ABCD. Among them, S1-101-102-103-104-105-405-404-403-402-401-S4 constitutes the first ring network, and S2-201-202-203-204-205-305-304-303-302-301-S3 constitutes the second ring network.

[0036] like Figure 3 As shown, the secondary main network distribution network structure can also be expanded into a single ring network multi-cascade access structure consisting of three distribution rooms based on the original grid structure. The twelfth switch 106 on the fifth bus C1 of the C distribution room and the thirteenth switch 206 on the sixth bus C2 are respectively connected to the original ring network main supply circuit to form a second distribution network structure, which includes the first power supply to the second power supply, the first switch to the second switch, and the first distribution unit to the third distribution unit. The second distribution unit also includes the tenth switch 105 and the eleventh switch 205, the tenth switch 015 is connected to the third bus B1, and the eleventh switch 205 is connected to the fourth bus B2.

[0037] The third power distribution unit includes the fifth busbar C1 to the sixth busbar C2, the twelfth switch 106 to the thirteenth switch 206, and the third section contact switch 503. One end of the twelfth switch 106 is connected to the third busbar through the tenth switch 105, and the other end is connected to the fifth busbar C1. One end of the thirteenth switch 206 is connected to the fourth busbar B2 through the eleventh switch 205, and the other end is connected to the sixth busbar C2. The fifth busbar C1 is connected to the sixth busbar C2 through the third section contact switch 503. The busbars of the power distribution units at all levels can also be connected to small power sources, such as Figure 3 As shown, a small power source can be connected to the fifth bus 603 node.

[0038] According to the characteristics of the dual-access cascade distribution network structure, the embodiment of the present invention also proposes a distributed self-healing system of the secondary backbone network distribution network structure. The specific system configuration is as follows Figure 4 As shown, it includes intelligent distributed terminal STU, switches and external protection devices. The intelligent distributed terminal STU is used to collect electrical quantity information and location information at each switch, and control the switch action based on the preset action logic. The STU needs to be configured according to the busbar. Each bus section of each distribution unit is configured with an STU. Adjacent STUs are connected by optical fiber, and information exchange between each other is achieved based on the GOOSE communication protocol. When a system failure occurs, the peer-to-peer communication function between multiple STUs can be used to quickly locate the fault, quickly isolate the fault, and quickly restore power supply to non-fault power-off areas. An independent external line longitudinal differential protection device is configured on the main supply circuit of the main trunk line. The above-mentioned external protection device is installed at each switch on the main supply circuit of the secondary trunk network distribution structure to control the action of each switch.

[0039] The self-healing system proposed in the present invention has the functions of fault location, fault isolation, power supply restoration in non-fault areas, etc.

[0040] 1) Fault location function

[0041] The fault location function of the above-mentioned self-healing system includes two methods: active location and passive location. Passive location refers to using the action signal of the external protection device, and connecting the action signal of the external protection device as an external input to the intelligent distributed terminal STU. When the signal is received, it is considered that the fault is located on the trunk line.

[0042] Active positioning means that the STU is equipped with various independent positioning elements for the faults of each trunk line, bus and bus feeder line in the ring network, such as network topology protection, line differential protection, bus differential protection and bus feeder line protection.

[0043] Passive positioning is preferred. When the differential action signal of the external protection device is not received, the positioning result of the internal fault positioning element is used. When the action signal of the external protection device is inconsistent with the internal fault positioning result of the STU, the fault positioning function uses the action signal of the external protection device.

[0044] 2) Fault isolation function

[0045] The fault isolation function of the above-mentioned self-healing system includes no-voltage tripping, line fault isolation, busbar fault isolation, feeder line fault isolation, failure protection, remote tripping, small power supply joint cutting and other functions. The fault isolation function is only allowed to operate when there is no current in the main supply circuit interval and no voltage on the busbar.

[0046] When the no-voltage tripping function is activated, the switch directly connected to the switch station on the side of the fault power outage on both sides of the open loop point will be tripped to isolate the fault. When there is a fault on the switch station side or the switch is tripped, the no-voltage tripping function should operate correctly; when the main line between the switch station and the distribution room fails and the external differential protection refuses to operate, the no-voltage tripping function should operate correctly. When a fault occurs in the ring network other than the main line between the switch station and the distribution room, the no-voltage tripping function should not operate correctly. In the case of a three-phase PT disconnection, the no-voltage tripping function should not malfunction.

[0047] For line fault isolation, STU should support the selection of working mode (active / passive) through control words to meet the needs of special projects. When the active tripping working mode is adopted, the line fault isolation function of STU will directly trip after the action conditions are met, and will not be affected by the exit of the self-healing function, and will have the same function as the external line protection device. When the passive mode is adopted, the line fault isolation function will operate the outlet under the condition of no pressure and no flow in the corresponding interval, and support the coordination with the external line protection reclosing function through time setting.

[0048] Busbar fault isolation adopts active function. When the busbar differential protection relay (full busbar differential) is actuated, all interval switches on the busbar section will be tripped and remotely tripped to the opposite side.

[0049] Feeder line interval protection, when a fault occurs in each feeder line interval, the corresponding interval overcurrent or zero-sequence overcurrent protection will operate to isolate the fault.

[0050] When the failure protection function is activated, all bay switches on the bus section will be tripped and the opposite side will be remotely tripped. When bay differential protection, bay topology protection, bay overcurrent protection, bay zero-sequence overcurrent protection, busbar differential protection, no-pressure tripping, fault location tripping, and follow-up tripping are activated, the switch failure judgment can be started; when failure protection, remote tripping, and other components are activated, the switch failure judgment will not be started.

[0051] The small power supply joint cutting function mainly considers that after the distributed power supply is connected, in the event of a power grid failure, in order to avoid the small power supply voltage support from affecting the self-healing gate function, the distributed power supply joint cutting process needs to be executed after the fault isolation is completed. The self-healing joint cutting small power supply object is the line defined as a small power supply in the distribution room between the fault point and the open loop point. When the main supply circuit on the power supply side of the station where the small power supply is located fails or the switch is tripped, the small power supply joint cutting action trips the small power supply branch. In the case of manual tripping, the small power supply joint cutting should not act.

[0052] 3) Power supply restoration function in non-fault areas

[0053] The above self-healing system's non-fault area power supply restoration function includes two power supply restoration functions: single-ring network self-healing and segmented standby automatic switching. The single-ring network self-healing function and the segmented standby automatic switching function can be put into operation at the same time. When both are put into operation at the same time, after the fault isolation is completed, the single-ring network self-healing method is preferentially used to realize the self-healing of the open-loop point switch.

[0054] When the self-healing switch is activated or the conditions for self-healing switch are not met, the power supply to the distribution room in the power-off state is restored by the section backup automatic function.

[0055] A model was built in the RTDS test environment, and the self-healing method of the secondary backbone network with a dual-access cascade structure was simulated and analyzed, as well as the action to restore power supply under various N-1 fault conditions. The test results show that this method can meet the self-healing power supply needs of the system under various N-1 fault conditions and ensure the reliability of power supply for users.

[0056] like Figure 5 As shown, the present invention also discloses a self-healing method for a distributed self-healing system of a secondary backbone distribution network structure, including steps 101 to 103.

[0057] Step 101: Obtain the fault location information through the fault location function.

[0058] Passive positioning is preferred. Passive positioning obtains the action signal of the external protection device through STU and determines the fault location based on the action signal. When no action signal of the external protection device is received, active positioning is used to determine the fault location based on the information of the internal fault positioning element.

[0059] If the external protection device action signal and the internal fault locating element information are received at the same time, and the fault locations determined according to the external protection device action signal and the internal fault locating element information are inconsistent, the fault locating result determined according to the external protection device action signal is used.

[0060] Step 102: According to the fault location information and the preset action logic of the distributed self-healing system, the corresponding switch node is controlled to be turned on to achieve fault isolation.

[0061] Specifically, when there is no current in the main supply circuit interval and no voltage in the busbar, the STU can achieve fault isolation through a variety of fault isolation functions. The following is a detailed description of the implementation steps of the no-pressure tripping function. The lines and switches including the third switch 102 to the eighth switch 204, the first section contact switch 501 to the second section contact switch 502 are defined as inside the ring, and the lines and switches including the first power supply to the second power supply, the first switch to the second switch, and the first switch and the third switch, the second switch and the fourth switch are defined as outside the ring. The no-pressure tripping function is used to achieve fault isolation.

[0062] If the fault location information indicates that a fault has occurred in the line or switch outside the loop, the switch directly connected to the switch station on the side of the fault power outage on both sides of the open loop point is tripped, and the no-voltage tripping function is activated to isolate the fault. Figure 1 When a fault occurs in the line on the S1 side of the medium power supply or the switch 101 is tripped, the no-pressure tripping function is activated to trip the switch 102 directly connected to the switch station to isolate the fault.

[0063] If the fault location information indicates that a line or switch in the ring has a fault, current discrimination is performed through a switch directly connected to the switch station. If a large reverse current flows through the switch directly connected to the switch station, it is determined that a fault has occurred in the ring network, and the no-voltage trip function is locked. For example, the current discrimination method of the switch 102 directly connected to the switch station can be adopted. If a large reverse current flows through the switch 102, it is determined to be a fault in the ring. At this time, the no-voltage trip function is locked and does not operate. In the case of a three-phase voltage transformer PT disconnection, the no-voltage trip should not malfunction.

[0064] In addition to the voltage-free tripping function, STU also includes a variety of fault isolation functions such as line fault isolation, busbar fault isolation, feeder fault isolation, failure protection, remote tripping, and small power supply joint cutting. When a fault occurs in the secondary backbone network, STU can use different functions to independently or jointly implement fault isolation according to the location and type of the fault, thereby improving the success rate of fault isolation.

[0065] Step 103: According to the fault location information and the preset action logic of the distributed self-healing system, the corresponding switch node is controlled to close to restore the normal power supply of the secondary main network.

[0066] After confirming that the fault has been successfully isolated, the single-ring network self-healing function is used to restore power supply. The STU sends a closing command to the open-loop point switch to restore power supply to the non-fault area.

[0067] The secondary trunk network of the single-ring network double-access cascade connection designed by the present invention has a fixed open-loop point, which is the sectional contact switch of the last-stage power distribution room. Figure 1The middle one is the section contact switch 502. After confirming that the fault has been successfully isolated and the no-pressure and no-current conditions are met, the STU issues a closing command to close the open-loop point switch, restore power supply to the non-fault area, and the system self-heals successfully.

[0068] After the single-ring network self-healing function is used to self-heal the open-loop point switch or when the single-ring network self-healing function startup conditions are not met, the sectional standby automatic re-entry function is used to restore power supply. At this time, the standby automatic re-entry function between the two-level distribution rooms does not require information exchange. When the sectional standby automatic re-entry is actuated, the incoming line switch interval in the ring and the outgoing line switch interval in the ring (hereinafter referred to as the ring-in and ring-out intervals) are tripped. After confirming that the ring-in and ring-out intervals are tripped, the sectional contact switch is closed after a short delay. In the case of a current transformer PT line break, the sectional standby automatic re-entry should not malfunction. When the incoming line interval trip position is abnormal, the sectional standby automatic re-entry should be locked. When the switch on the power supply side of this distribution room or the upper-level trunk network is manually tripped or there is a "locked self-healing and standby automatic re-entry" turned on, the sectional standby automatic re-entry should be locked.

[0069] Furthermore, according to the preset pressure plate activation state on the STU, it is determined whether the incoming switch interval or the outgoing switch interval is controlled by the segmented backup automatic switching function. When the "backup automatic switching exit first interval" pressure plate is activated, the first interval switch is not controlled by the backup automatic switching function. If the "backup automatic switching exit first interval" pressure plate is not activated, the first interval switch is controlled by the backup automatic switching function. The above-mentioned first interval is any incoming switch interval or outgoing switch interval within the ring

[0070] For example, Figure 1 As shown, the 103 interval is selected as the small power source. When the 203-204 line is under maintenance, the A1 busbar of the A distribution room supplies power to the B distribution room via the 103-104 single line. At this time, the "standby automatic switch exit interval 103" pressure plate can be activated to make only the interval 102 trip when the standby automatic switch trips, so as to reduce the risk of power outage in the B distribution room at this time.

[0071] Example 1

[0072] by Figure 6 The first distribution network structure shown is used as an example for further explanation. The sectionalized contact switch 502 is an open loop point. Since the left side is symmetrical with the right side, the self-healing action of the fault is the same, so only the left side is used as an example for explanation. The following faults involve single-phase grounding faults and phase-to-phase faults.

[0073] 1) The upper level loses power. When the power supply S1 side of the upper level switch station loses power, as shown in the figure, after the F1 point fails:

[0074] a) 102 no-voltage tripping action, after 102 switch trips, it automatically heals and cuts off the small power supply 602, and after bus 1 in the B distribution room meets the no-voltage condition, it automatically heals the 502 switch and restores power supply;

[0075] b) If switch 102 refuses to trip, 102 no-voltage tripping will be actuated and the self-healing small power supply 602 will be disconnected. The 102 failure protection will be actuated, switches 103 and 501 will be tripped, and switch 104 will be remotely tripped. Switch 502 will be self-healed and power supply will be restored.

[0076] 2) Trunk line F2 failure

[0077] a) After the externally configured line longitudinal differential protection is actuated, the 102 differential input protection is actuated. After 102 is tripped, the self-healing and interlocking small power source 602 is disconnected and connected to 502. The power supply of A1 and B1 buses is restored;

[0078] b) If switch 102 refuses to trip, after the externally configured line longitudinal differential protection is activated, the 102 failure protection is activated, tripping switches 103 and 501, and remotely tripping switch 104, self-healing switch 502, and restoring power supply;

[0079] c) If the external longitudinal differential protection is withdrawn, the backup protection 101 will be activated, the fault will be disconnected and the small power supply 602 will be tripped. After 102 meets the no-voltage tripping logic, it will trip and the self-healing circuit breaker 502 will be restored to restore power supply.

[0080] 3) A1 bus F3 fault

[0081] a) The A1 busbar protection is activated, all busbar branches are tripped, and the 104 switch is remotely tripped. The small power supply 602 switch is self-healed and connected to 502. The B1 busbar is restored to power supply;

[0082] b) If the 103 switch or the 104 switch refuses to trip, the busbar protection will trip all branch switches and trip remotely, and then the small power supply will be connected to the 602 switch, and the 502 switch will be closed, and the B1 busbar will resume power supply;

[0083] c) If the A1 busbar protection refuses to operate, the 101 backup protection will operate, the fault will be disconnected and the small power supply 602 will be tripped, the fault isolation is not completed, and the self-healing discharge will not operate.

[0084] 4) Branch line F4 fault

[0085] a) If the overcurrent protection of the 601 branch line operates normally, it will return to normal after the fault is cut off, and self-healing will not operate;

[0086] b) If the 601 switch refuses to trip, the branch line failure protection will trip other branches of the A1 bus, and remotely trip the 104 switch, self-healing and connecting the small power supply 602 switch, self-healing and entering the 502 switch, and the B1 bus will resume power supply;

[0087] c) If the 601 protection refuses to operate, the 101 backup protection will operate to trip the 101 switch, and the fault will trip the small power supply 602 switch. At this time, the fault isolation is not completed and the self-healing discharge will not operate.

[0088] 5) Trunk line F5 failure

[0089] a) The externally configured line longitudinal differential protection is activated, switches 103 and 104 are tripped, the self-healing small power source 602 is cut off, and 502 is connected to restore power supply;

[0090] b) If switch 104 refuses to trip, the externally configured line longitudinal differential protection will trip switch 103, and switch 104 failure protection will trip other switches on bus B1. At this time, fault isolation is not completed and self-healing discharge will not work;

[0091] c) If the external longitudinal differential protection is withdrawn, the STU differential protection will be activated in active mode to open switches 103 and 104, the fault will be disconnected to open the small power supply 602, the self-healing will cut off the small power supply 602, and 502 will be connected to restore power supply.

[0092] 6) B1 bus F6 fault

[0093] a) B1 busbar protection is activated, all busbar branches are tripped, and switch 103 is remotely tripped. Fault isolation is not completed, and self-healing discharge does not operate;

[0094] b) If the B1 busbar protection refuses to operate, the 103 backup protection will operate, the fault will be disconnected and the small power supply 602 will be tripped, the fault isolation is not completed, and the self-healing discharge will not operate.

[0095] 7) Small power branch F7 fault

[0096] a) If the overcurrent protection of the 602 branch line operates normally, it will return to normal after the fault is cut off, and self-healing will not operate;

[0097] b) If the 602 switch refuses to trip, the branch line failure protection will trip other branches of the B1 bus and remotely trip the 103 switch. The fault isolation is not completed and the self-healing discharge will not operate.

[0098] c) If the 602 protection refuses to operate, the 103 backup protection will operate to trip the 103 switch, and the fault will trip the small power supply 602 switch. At this time, the fault isolation is not completed and the self-healing discharge will not operate.

[0099] 8) Switch tripping

[0100] a) The 101 switch tripped secretly, the fault was cleared and the small power supply 602 switch was tripped, and the 102 no-voltage trip was actuated. After the bus 1 in the B distribution room met the no-voltage condition, the 502 switch was automatically healed and the power supply was restored.

[0101] b) The 102 switch (or 103, 104 switches) trips secretly, the fault is tripped and the small power supply 602 switch is tripped, the self-healing 502 switch is switched on, and the power supply is restored.

[0102] 9) Switch manual trip

[0103] Manual tripping of the switch is an operation by the operator and requires switching the operating mode. At this time, the self-healing system should not be activated. Therefore, when the 101 switch (or 102, 103, 104 switches) is manually tripped, the self-healing system discharges and does not operate.

[0104] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents. 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 embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A self-healing method for a distributed self-healing system of a secondary backbone network distribution network structure, characterized in that: The method is applicable to a distributed self-healing system of a secondary backbone network distribution network structure, wherein the secondary backbone network distribution network structure comprises a first distribution network structure, wherein the first distribution network structure comprises a first power supply to a second power supply, a first switch to a second switch, and a first distribution unit to a second distribution unit; The first power distribution unit adopts a single busbar segmented wiring mode, the first power supply is connected to the first busbar of the first power distribution unit, and the second power supply is connected to the second busbar of the first power distribution unit, so as to realize dual power supply of the first power distribution unit; the second power distribution unit adopts a single busbar segmented wiring mode, cascadedly connected to the first power distribution unit, the third busbar is connected to the first busbar, and the fourth busbar is connected to the second busbar, so as to realize dual power supply of the second power distribution unit; The first power distribution unit includes a first busbar to a second busbar, a third switch to a sixth switch, and a first section contact switch; the first power supply is connected to the first busbar through the first switch and the third switch, the second power supply is connected to the second busbar through the second switch and the fourth switch, and the first busbar is connected to the second busbar through the first section contact switch; the second power distribution unit includes a third busbar to a fourth busbar, a seventh switch to an eighth switch, and a second section contact switch; one end of the seventh switch is connected to the fifth switch, and the other end is connected to the third busbar, one end of the eighth switch is connected to the sixth switch, and the other end is connected to the fourth busbar, and the third busbar is connected to the fourth busbar through the second section contact switch; The first power source is connected to the first switch, the third switch, the fifth switch and the seventh switch in sequence, and the second power source is connected to the second switch, the fourth switch, the sixth switch and the eighth switch in sequence, forming a main supply circuit of the first distribution network structure; The method comprises: Obtain the fault location information through the fault location function; According to the fault location information and the preset action logic of the distributed self-healing system, control the action of the corresponding switch node to achieve fault isolation; According to the fault location information and the preset action logic of the distributed self-healing system, control the action of the corresponding switch node to restore the normal power supply of the secondary backbone network; According to the fault location information and the preset action logic of the distributed self-healing system, the distributed self-healing system operates to control the corresponding switch node to restore the normal power supply of the secondary backbone network, including: Confirm that the fault has been successfully isolated, and give priority to the single-ring network self-healing function for power restoration. The STU sends a closing command to the open-loop point switch to restore power supply to the non-fault area; the open-loop point is the sectional contact switch of the last-level distribution unit; After the single-ring network self-healing function is used to self-heal the open-loop point switch or when the conditions for starting the single-ring network self-healing function are not met, the sectional backup automatic transfer function is used to restore power supply. No information exchange is performed between distribution units at all levels. After the incoming line switch interval or the outgoing line switch interval within the ring is tripped, the sectional interconnecting switch in the distribution unit is closed.

2. The self-healing method of the distributed self-healing system of the secondary backbone network distribution structure according to claim 1, characterized in that: The obtaining of fault location information through the fault location function includes: The STU obtains an action signal of an external protection device and determines the fault location through the action signal of the external protection device; when no action signal of the external protection device is received, the fault location is determined using information of an internal fault locating element; If the external protection device action signal and the internal fault locating element information are received at the same time, and the fault locations determined according to the external protection device action signal and the internal fault locating element information are inconsistent, the fault locating result determined according to the external protection device action signal is adopted.

3. The self-healing method of the distributed self-healing system of the secondary backbone network distribution structure according to claim 1, characterized in that: The controlling the corresponding switch node action according to the fault location information and the preset action logic of the distributed self-healing system to achieve fault isolation includes: The lines and switches including the third switch to the eighth switch and the first section contact switch to the second section contact switch are defined as inside the ring, and the lines including the first power supply to the second power supply, the first switch to the second switch, and the lines between the first switch and the third switch, and the second switch and the fourth switch are defined as outside the ring; the voltage-free tripping function is used to achieve fault isolation; The application of the no-pressure tripping function to achieve fault isolation includes: If the fault location information indicates that a fault occurs in the line or switch outside the loop, the switch directly connected to the switch station on the side of the fault power outage on both sides of the open loop point is tripped, and the no-pressure tripping function is activated to isolate the fault; If the fault location information indicates that a line or switch within the ring has a fault, current identification is performed through a switch directly connected to the switch station. If a large reverse current flows through the switch directly connected to the switch station, it is determined that a fault has occurred within the ring network, and the no-pressure tripping function is locked.

4. The self-healing method of the distributed self-healing system of the secondary backbone network distribution structure according to claim 1, characterized in that: The tripping of the incoming line switch interval or the outgoing line switch interval in the ring also includes: According to the preset pressure plate activation status on the STU, determine whether the incoming line switch interval or the outgoing line switch interval within the ring is controlled by the segmented standby automatic transfer function. When the "standby automatic transfer exits the first interval" pressure plate is activated, the first interval switch is not controlled by the standby automatic transfer function. When the "standby automatic transfer exits the first interval" pressure plate is not activated, the first interval switch is controlled by the standby automatic transfer function. The first interval is any incoming line switch interval or outgoing line switch interval within the ring.

5. The self-healing method of the distributed self-healing system of the secondary backbone network distribution structure according to claim 1, characterized in that: The distributed self-healing system includes an intelligent distributed terminal STU, a switch and an external protection device; The STU is used to collect electrical quantity information and position information at each switch, and control the corresponding switch action based on the preset action logic; The STU is configured according to the bus position, and each bus section of each power distribution unit is configured with an STU, and adjacent STUs are connected by optical fiber to achieve peer-to-peer interactive communication; The external protection device is installed at each switch on the main supply circuit of the secondary main network distribution network structure and is used to control the operation of each switch.

6. The self-healing method of the distributed self-healing system of the secondary backbone network distribution structure according to claim 5, characterized in that: The STU can achieve at least one of the following functions: fault location, fault isolation, and power supply restoration to non-faulty areas; The fault location function includes active location and passive location; The fault isolation function includes at least one of no-voltage tripping, line fault isolation, busbar fault isolation, feeder fault isolation, failure protection, remote tripping and small power supply joint cutting functions; The non-fault area power supply recovery function includes a single-ring network self-healing function and a segmented backup automatic switching function.

7. The self-healing method of the distributed self-healing system of the secondary backbone network distribution structure according to claim 1, characterized in that: The secondary backbone network distribution network structure further includes a second distribution network structure, wherein the second distribution network structure includes a first power supply to a second power supply, a first switch to a second switch, and a first distribution unit to a third distribution unit; The second power distribution unit further includes a tenth switch and an eleventh switch, the tenth switch is connected to the third bus, and the eleventh switch is connected to the fourth bus; The third power distribution unit includes the fifth bus to the sixth bus, the twelfth switch to the thirteenth switch, and a third section connecting switch; one end of the twelfth switch is connected to the third bus through the tenth switch, and the other end is connected to the fifth bus, one end of the thirteenth switch is connected to the fourth bus through the eleventh switch, and the other end is connected to the sixth bus, and the fifth bus and the sixth bus are connected through the third section connecting switch.

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