Distribution network power supply restoration method and system considering coordination of multiple types of distributed power sources

Abstract

The present application discloses a distribution network power supply restoration method and system taking into account the coordination of multiple types of distributed power sources. The method includes: when the fault section is successfully isolated, the grid-type DG in the power-off area is switched on without voltage; a source-load balance island is constructed based on the grid-type DG, and important loads are restored first; when there is no connection, the switch upstream of the fault point is reclosed without voltage to handle transient faults and plan the island to be connected to the grid; when there is connection, the optimal connecting switch is selected according to the connecting line and the power-off load capacity, and the irrecoverable section is cut off and then closed. The capacity of the adjacent grid-type DG is considered, and the power is restored in stages by cyclically cutting off the irrecoverable load, connecting the grid-type DG to the grid, and updating the recoverable capacity. When the adjacent section of the island is restored, the connected switches are synchronized and connected to the grid. The present invention realizes the maximum capacity safe restoration of the load in the non-fault section through the coordinated control strategy of multiple types of DGs, gives full play to the active support capability of DG, and significantly improves the reliability of the distribution system.

Description

Technical Field

[0001] The present invention belongs to the technical field of medium-voltage distribution network power supply restoration, and in particular relates to a distribution network power supply restoration method and system taking into account the coordination of multiple types of distributed power sources. Background Art

[0002] With the large-scale access of distributed generators (DGs) to distribution networks, existing fault power supply restoration methods usually adopt the active DG removal strategy. Traditional single-path restoration solutions have limitations and fail to fully utilize the supporting role of DGs, making it impossible to achieve multi-objective collaborative optimization of power supply restoration.

[0003] In the existing technologies, such as CN119482659A and CN119209521A, although they involve island division and transient optimization, they have the following technical defects: (1) Traditional centralized control relies on global optimization of the master station, which has the problems of high communication delay and poor real-time performance; (2) The existing DG fault ride-through coordination mechanism is imperfect. For example, the impact of the dynamic characteristics of DG low voltage ride-through on the recovery strategy is not fully considered, resulting in a sharp drop in the system support capacity after the DG is removed; (3) The communication path selection strategy is single. For example, there is a lack of analysis of DG output fluctuations and line capacity margin, which may cause overload. Summary of the Invention

[0004] In order to address the deficiencies in the prior art, the present invention provides a distribution network power supply restoration method and system taking into account the coordination of multiple types of distributed power sources, solving the problems raised in the above-mentioned background technology, making full use of the supporting role of DG, realizing multi-objective collaborative optimization of power supply restoration, improving the reliability of the distribution system, and being suitable for medium-voltage distribution network systems.

[0005] The present invention adopts the following technical solutions.

[0006] A first aspect of the present invention provides a method for power distribution network restoration taking into account the coordination of multiple types of distributed power sources, comprising:

[0007] Obtain the fault section isolation success signal and determine the power failure area;

[0008] Cut off all grid-connected distributed power sources in the power-off area that are connected to the node that receives the isolation success signal;

[0009] When the power outage area includes grid-type distributed power generation nodes, a planned island is constructed. Within each planned island, the order of load power restoration is determined based on the load level, and the smallest restoration unit with the highest load level is restored first.

[0010] When the power outage area is disconnected from other areas of the distribution network, the system detects the status of the no-voltage reclosing switch upstream of the fault point and determines the power restoration strategy based on the fault type and the no-voltage reclosing status.

[0011] When the power outage area is connected to other areas of the distribution network, the optimal tie switch is determined based on the tie line and the power of the power-lost load. After the irrecoverable section is cut off, the optimal tie switch is closed. Based on the capacity of the adjacent grid-connected distributed power sources, power is restored in stages by cyclically cutting off the irrecoverable load, connecting the grid-connected distributed power sources, and updating the restorable capacity until there are no more restorable sections.

[0012] When the power supply is restored to the adjacent section of the island, the switches connected to the island area and the area restored by the tie switch are synchronized and connected to the grid, and power supply to the remaining loads in the island is restored according to the load power supply restoration sequence and the updated restorable capacity.

[0013] Optionally, the planned island includes multiple minimum restoration units. Within each planned island, the load power supply restoration sequence is determined based on the load level, including:

[0014] Calculate the load power of each minimum restoration unit;

[0015] When the load is greater than or equal to the minimum restoration unit load power, the load power supply restoration order is determined based on the total power supply load capacity, load level and corresponding constraints of different loads in the preset time period.

[0016] Optionally, the constraint condition of the total power supply load capacity of the load in the preset time period is that the total power supply load capacity of the load in the preset time period is less than the capacity of the grid-forming distributed power supply. The load power supply restoration order is determined based on the total power supply load capacity of different loads in the preset time period, the load level, and the corresponding constraint conditions, including:

[0017] The load is divided according to the sum of the capacity of the grid-type distributed power sources and the constraint condition of the total capacity of the power supply load in the preset time period of the load to obtain multiple load sets;

[0018] Determine the load power supply sequence according to load level among multiple load concentrations, and allocate restorable load capacity according to load level.

[0019] Optionally, the power restoration strategy includes transient faults and permanent faults.

[0020] Optionally, determining the optimal tie switch according to the tie line and the power of the power-off load includes:

[0021] Calculate the recoverable capacity of the grid-connected distributed power source connected to the island;

[0022] Calculate the maximum transfer power of each tie line before power supply is restored;

[0023] The maximum restoration capability of the maximum transfer power of each tie line is calculated based on the restorable capacity and the maximum transfer power of each tie line before power supply is restored, and the optimal tie switch is determined based on the maximum restoration capability of the maximum transfer power of each tie line.

[0024] Optionally, calculating the maximum restoration capability of the maximum transfer power of each tie line based on the restorable capacity and the maximum transfer power of each tie line before power restoration, and determining the optimal tie switch based on the maximum restoration capability of the maximum transfer power of each tie line, including:

[0025] The maximum restoration capacity of the maximum transfer power of each tie line is obtained by summing the restorable capacity and the maximum transfer power of each tie line before power restoration.

[0026] The tie line corresponding to the maximum value among the maximum restoration capabilities is selected as the optimal tie switch.

[0027] Optionally, after the grid-connected distributed power source is connected to the grid and the restorable capacity is updated, the method further includes:

[0028] Update the power and load power of the non-fault section, and determine whether to restore power in stages based on the updated power and load power of the non-fault section and the updated recoverable capacity.

[0029] Optionally, update the recoverable capacity as follows:

[0030] ,

[0031] Where, For recoverable capacity, This is a collection of restored power supply sections. is the maximum transfer power of the interconnection line n, is the active power of the grid-following distributed power supply in the non-fault power-off section connected to the island area before the fault. It is the ratio of pre-fault active power that can be output within the preset time period when the voltage at the common connection point reaches the normal operating range.

[0032] Optionally, the method further includes:

[0033] Based on the power supply restoration capacity constraint condition, it is determined whether there is a restorable section, and the power supply restoration capacity constraint condition is that the load capacity in a preset time period is less than or equal to the maximum transfer power of the interconnection line.

[0034] A second aspect of the present invention provides a distribution network power restoration system taking into account the coordination of multiple types of distributed power sources, the system comprising:

[0035] Determination module, used to obtain the fault section isolation success signal and determine the power failure area;

[0036] A cut-off module is used to cut off all grid-connected distributed power sources connected to the nodes that have received the isolation success signal in the power-off area;

[0037] A construction module is used to construct planned islands when the power outage area contains grid-type distributed power generation nodes. Within each planned island, the load power supply restoration order is determined based on the load level, and the minimum restoration unit with the highest load level is restored first.

[0038] The first restoration module is used to detect the status of the no-voltage reclosing switch upstream of the fault point when there is no communication between the power outage area and other areas of the distribution network, and determine the power supply restoration strategy based on the fault type and the status of the no-voltage reclosing switch;

[0039] The second restoration module is used to determine the optimal tie switch based on the tie line and the power of the power-lost load when the power-lost area is connected to other areas of the distribution network. After removing the unrecoverable section, the optimal tie switch is closed. Based on the capacity of adjacent grid-connected distributed power sources, power is restored in stages by cyclically removing unrecoverable loads, connecting grid-connected distributed power sources, and updating the recoverable capacity until there are no more recoverable sections.

[0040] The third recovery module is used to synchronize the switches connected to the island area and the tie switch closing recovery area when the recovery is to the adjacent section of the island, and restore power to the remaining loads in the island according to the load power supply recovery sequence and the updated restorable capacity.

[0041] The third aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, the method for restoring power supply to the distribution network taking into account the coordination of multiple types of distributed power sources is implemented.

[0042] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned distribution network power supply restoration method taking into account the coordination of multiple types of distributed power sources.

[0043] Compared with the prior art, the beneficial effects of the present invention include at least:

[0044] This paper proposes a distribution network power restoration method that takes into account the collaboration of multiple types of distributed power sources. By deploying intelligent self-healing terminals at key nodes and building a horizontal peer-to-peer communication network, this method employs a "distributed control + multi-stage collaboration" architecture. The method adaptively selects the optimal path based on the capacity margin indicator of the interconnecting lines. This method uses short-latency channels to achieve real-time topology identification and dynamic capacity margin correction between intelligent self-healing terminals, enabling multi-stage and maximum-scale power restoration. This method can safely restore loads in non-faulty sections to their maximum capacity, fully leveraging the supporting role of different types of distributed generators in the power restoration process, significantly improving the reliability of the distribution system.

[0045] The present invention proposes for the first time a method for adaptively selecting the optimal power transfer path based on the interconnection line capacity margin index, which solves the problems of insufficient adaptability and limited load recovery of traditional single fixed power transfer.

[0046] The present invention proposes for the first time a method for dynamically updating the recoverable capacity margin based on rapid interaction between terminal information, thereby realizing multi-stage and maximum-range power supply restoration.

[0047] The present invention proposes a priority power supply restoration strategy for important loads based on the active construction of isolated islands by grid-type DG, which improves the level of local and nearby consumption of new energy and the continuous power supply capacity of important loads.

[0048] The present invention proposes a power supply restoration method that takes into account the supporting role of different types of DGs, achieves maximum capacity safe restoration of loads in non-fault sections, and significantly improves the reliability of the distribution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0050] Figure 1 A schematic flow chart of a power restoration method taking into account the coordination of multiple types of distributed power sources provided in a specific embodiment of the present invention;

[0051] Figure 2 A diagram illustrating the division of a minimum recovery unit provided for a specific embodiment of the present invention;

[0052] Figure 3 A typical multi-connection network implementation diagram provided for a specific embodiment of the present invention. DETAILED DESCRIPTION

[0053] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0054] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0055] like Figure 1 As shown, embodiment 1 of the present invention provides a power restoration method that takes into account the coordination of multiple types of distributed power sources, which is applicable to medium-voltage distribution network systems and realizes rapid, safe, and orderly power restoration in non-fault sections. Specifically, it includes the following steps:

[0056] Step 1: Obtain a signal indicating successful isolation of the faulty section and determine the power-off area.

[0057] Preferably, the fault power-off area includes:

[0058] Based on the information interaction between nodes, the switch of the first node connecting the power supply side and the load side of the fault point trips to isolate the fault section, and the area composed of the tripping node on the load side to the end node is the power-off area.

[0059] As shown in Table 1, nodes include load nodes, DG nodes, and contact nodes. Load nodes are divided into primary, secondary, and tertiary levels according to load levels, and DG nodes are divided into network-following type and network-forming type according to type.

[0060] Table 1

[0061]

[0062] In Table 1, 0 indicates that the node does not correspond to the level load, and 1 indicates that the node corresponds to the level load.

[0063] Step 2: Cut off all grid-connected distributed power sources in the power-off area that are connected to the node that receives the isolation success signal.

[0064] By jointly cutting the grid-following DG in the power-off area, the conditions for no-pressure reclosing or interconnected closing can be met.

[0065] Specifically, after receiving the signal that the fault section is successfully isolated, the node whose node information is a grid-following DG will switch off the connected grid-following DG, meeting the conditions for no-pressure reclosing or interconnected closing.

[0066] No-voltage reclosing means that when a line fault causes tripping, if it is detected that there is no voltage in the line, it is considered that the fault has been eliminated, and the reclosing device will issue a closing command to try to restore power supply.

[0067] The interconnection closing is to achieve the connection and power restoration between power supply systems through the interconnection switch. When one of the systems fails or there is a power outage, the interconnection switch is closed and the other system supplies power to the power outage area.

[0068] The condition for no-pressure reclosing or interconnected closing is that there is pressure on one side of the system power supply. If the grid-following DG is not disconnected from the grid, there will be pressure on both sides, which will not meet the condition for no-pressure reclosing or interconnected closing.

[0069] Step 3: When the power outage area contains a meshed DG node, construct a planned island, determine the load power supply restoration order according to the load level within each planned island, and give priority to restoring the smallest restoration unit with the highest load level.

[0070] In this embodiment, by constructing a planned island through source-load balancing conditions, it is possible to ensure continuous power supply to important loads and reduce power outage time.

[0071] Preferably, said constructing planned islands based on the source-load balance condition and determining the load power supply restoration order according to the load level in each planned island includes:

[0072] Step 3.1: When the power outage area contains a grid-forming DG node, construct a planned island based on the source-load balance condition and determine the load power of each minimum restoration unit:

[0073]

[0074] Where, is the load power of the i-th minimum restoration unit, is the power of the upstream boundary switch of the minimum restoration unit, m is the number of boundary switches in the minimum restoration unit, t is the cross-section time of normal operation before the fault occurs,

[0075] is the sum of the power of each downstream boundary switch of the minimum recovery unit, Inject power into the DG in the section where the minimum recovery unit is located.

[0076] The minimum recovery unit load power is the total load that the minimum recovery unit can support.

[0077] like Figure 2 As shown, Figure 2This is an interpretation diagram of the minimum restoration unit division. The minimum restoration unit is an area composed of the main line section switch and branch / boundary switch, branch switch and boundary switch, and no other switches with three remote functions are contained inside.

[0078] Figure 2 In the figure, the substation outgoing line switch CB and the main line section switch FD1, the main line section switch FD1 and the main line section switch FD2, the branch switch FS1, the branch switch FS1 and the boundary switch YS1, the main line section switch FD2 and the main line section switch FD3, the branch switch FS2, the branch switch FS2 and the boundary switch YS2, the tie switch LSW1, the main line section switch FD3 and the main line section switch FS4, the main line section switch FS4 and the branch switch FS3, the tie switch LSW2, the branch switch FS3 and the boundary switch YS3 respectively constitute the minimum restoration unit.

[0079] Combine Figure 2 As shown, the load power of the minimum recovery unit 1 for:

[0080]

[0081] Where, is the minimum recovery unit 1 upstream switch CB power, is the sum of the power of the downstream trunk line segment switches, Figure 2 It can be seen that there is no DG in the minimum restoration unit, so the DG injection power is 0.

[0082] Load power of minimum recovery unit 7 for:

[0083]

[0084] Where, is the minimum recovery unit 7 upstream switch FS2 power, is the sum of the power of the downstream trunk line segment switches, Inject power into the DG section where the minimum restoration unit 7 is located.

[0085] Step 3.2: When the load is greater than or equal to the minimum restoration unit load power, determine the load power restoration order based on the total power supply load capacity, load level and corresponding constraints of different loads in the preset time period. Step 3.2 specifically includes:

[0086] Step 3.2.1: The constraint condition of the total power supply load capacity of the load in the preset time period is that the total power supply load capacity of the load in the preset time period is less than the grid-type DG capacity. When the load is greater than or equal to the minimum restoration unit load power, the first index value of the load is determined according to the constraint condition of the total power supply load capacity of the load in the preset time period.

[0087] The total capacity of the priority restored power supply load must be less than the capacity of the grid-forming DG, and the constraints are:

[0088]

[0089] Where, is the sum of the capacity of the network-type DG at time t, is the load capacity at time t.

[0090] Specifically, when the total power supply load capacity of the load in the preset time period is less than the capacity of the grid-forming DG, the first indicator value may be set to 3; otherwise, the first indicator value may be set to 0.

[0091] Step 3.2.2: Determine the second load index value based on the load level and its corresponding constraints.

[0092] Specifically, the load levels include primary load, secondary load and tertiary load.

[0093] The first-level load is restored first, and the following conditions must be met:

[0094]

[0095] in, Prioritize capacity restoration for primary loads. is the primary load capacity ratio coefficient, Greater than or equal to 60%, is the load capacity at time t.

[0096] Secondary loads are restored first, and the remaining capacity allocation must meet the following requirements:

[0097] (4)

[0098] in, The secondary load has the second highest priority in restoring capacity. is the secondary load capacity ratio coefficient, Greater than or equal to 60%, is the load capacity at time t.

[0099] For the three-level load dynamic recovery, the remaining capacity allocation must meet the following requirements:

[0100] (5)

[0101] in, Dynamically restore capacity for level 3 load.

[0102] Specifically, when the first-level load recovery capacity is less than or equal to the first-level load capacity ratio of the total power supply load capacity, the second indicator value is set to 3, otherwise it is 0; when the second-level load recovery capacity is less than or equal to the second-level load capacity ratio of the total power supply load capacity, the second indicator is set to 2, otherwise it is 0; when the third-level load recovery capacity is less than or equal to the third-level load capacity ratio of the total power supply load capacity, the second indicator is set to 1, otherwise it is 0, where the sum of the third-level load capacity ratio, the first-level load capacity ratio and the second-level load capacity ratio is 1.

[0103] Step 3.2.3: Determine the load power supply restoration order based on the first index value and the second index value of the load.

[0104] Specifically, the first and second index values ​​of the loads and their corresponding weights are summed and calculated, and the order of load power supply restoration is determined according to the calculation result. The larger the calculation result, the higher the priority for restoring load power supply.

[0105] Specifically, the order of restoring power to the loads is determined based on the multiplication result of the first and second index values ​​of the loads. The larger the calculated result, the higher the priority for restoring power to the loads.

[0106] It is understandable that the specific numbers of the first index value, the second index value and the weight are set according to actual applications, and this embodiment does not limit this.

[0107] In some embodiments, step 3.2 specifically includes:

[0108] The load is divided according to the sum of the capacity of the grid-forming DGs and the constraint condition of the total capacity of the power supply load in the preset time period of the load to obtain multiple load sets;

[0109] Determine the load power supply sequence according to load level among multiple load concentrations, and allocate restorable load capacity according to load level.

[0110] It can be allocated proportionally or according to load level weights.

[0111] In this embodiment, a priority power supply restoration strategy for important loads on isolated islands is constructed based on the grid-type DG, which improves the level of local consumption of new energy and the continuous power supply capacity of important loads.

[0112] Step 4: When the power-off area is not connected to other areas of the distribution network, detect the status of the no-voltage reclosing switch upstream of the fault point and determine the power supply restoration strategy based on the fault type and the status of the no-voltage reclosing switch.

[0113] No connection means that there is no direct electrical connection between certain areas or lines in the power grid, or there is no backup power supply path. These areas or lines are independent under normal circumstances and cannot be powered by other lines or power sources.

[0114] Preferably, when there is no communication, the power supply recovery strategy includes transient faults and permanent faults. Step 4 specifically includes:

[0115] Step 4.1: Restoring power supply from a transient fault when there is no communication, including:

[0116] 1) If the fault type and the status of the no-pressure reclosing circuit breaker are judged to be a transient fault and the reclosing circuit breaker is successful, the power supply from the island power supply side switch to the busbar area load is restored;

[0117] 2) The grid-following DG that actively connects the switch on the island power supply side to the bus area is fully connected to the grid when the system voltage meets the [-5%, +5%] condition;

[0118] 3) The switch on the island power supply side checks the synchronization and closes to restore power to the loads in the island area that failed to be restored in priority in step 3;

[0119] 4) The switch on the island load side is closed, and the grid-following DG that is actively connected to the terminal area by the switch on the island load side is fully connected to the grid when the system voltage meets the [-5%, +5%] condition;

[0120] 5) All loads on the instantaneous fault line are restored to power.

[0121] Step 4.2: Restoration of power supply from a permanent fault when there is no communication, including:

[0122] 1) Based on the fault type and the status of the no-pressure reclosing switch, it is determined that the reclosing fails due to a permanent fault. The switch on the island power supply side is restored until the load in the bus area loses power again;

[0123] 2) When the adjacent section of the island contains a grid-following DG, that is, when a grid-following DG is directly connected to the island area, it is fully connected to the grid, otherwise the power supply restoration process ends;

[0124] 3) After the grid-connected DG is fully connected to the grid, the capacity margin can be restored based on the grid-connected capacity of the grid-connected DG;

[0125] 4) Based on the power supply restoration capacity constraint condition (10), determine whether there is a restorable section. If there is a restorable section, remove the unrestorable load based on the source-load balance, and complete the staged power restoration;

[0126] 5) Cyclic search is performed to determine whether there are any isolated areas directly connected to the grid-type DG, and the load of the areas connected to the isolated areas is restored in stages until there are no more recoverable sections.

[0127] Step 5: When the power-off area is connected to other areas of the distribution network, the optimal tie switch is determined based on the tie line and the power of the power-off load. After the irrecoverable section is cut off, the optimal tie switch is closed. Based on the capacity of the adjacent grid-following DG, power is restored in stages by cyclically cutting off the irrecoverable load, connecting the grid-following DG, and updating the restorable capacity until there are no more restorable sections.

[0128] Step 5.1: Determine the optimal tie switch based on the tie line and the power of the power-off load. Step 5.1 specifically includes:

[0129] Step 5.1.1: Calculate the recoverable capacity of the grid-connected DG connected to the island.

[0130] Preferably, the recoverable capacity of the grid-connected DG connected to the island includes:

[0131] (6)

[0132] Where, is the maximum value of recoverable capacity, is the active power before the fault of the grid-following DG in the non-fault power-off section connected to the island area, It is the set of non-fault power-off sections connected to the island area; When the PCC (Point of Common Coupling) voltage reaches the normal operating area, the active power ratio before the fault can be output within the preset time. The value can be 0.8, and the preset time is set according to actual needs.

[0133] It can be understood that the recoverable capacity in formula (6) is the recoverable capacity after the grid-type DG connected to the island is connected to the grid.

[0134] Step 5.1.2: Calculate the maximum transfer power of each interconnection line before power is restored.

[0135] Preferably, the maximum transfer power of the tie line before power supply is restored (i.e., transfer) is calculated according to the following formula:

[0136] (7)

[0137] Where, is the maximum transfer power of the interconnection line n; is the rated power of the interconnection line n; is the load power of interconnection line n before transfer.

[0138] Step 5.1.3: Calculate the maximum restoration capability of the maximum transfer power of each tie line based on the restorable capacity and the maximum transfer power of each tie line before power restoration, and determine the optimal tie switch based on the maximum restoration capability of the maximum transfer power of each tie line.

[0139] Calculate the sum of the restorable capacity and the maximum transfer power of each tie line before power is restored, and select the tie line corresponding to the maximum sum as the optimal tie switch.

[0140] The maximum restoration capability of the maximum transfer power of the tie line is calculated by formulas (6) and (7):

[0141] (8)

[0142] Where, It is the maximum recovery capacity of the maximum transfer power of the tie line, that is, the recoverable capacity considering the remaining capacity of the tie switch. The largest tie line serves as the optimal tie switch.

[0143] Step 5.2: Update the power sum of the power loss load in the non-fault section:

[0144] (9)

[0145] Where, is the power sum of the power loss load in the non-fault section, is the load power of non-fault section i, m is the set of all non-fault sections, and i is the i-th section in the non-fault section.

[0146] Step 5.3: When the maximum restoration capacity of the maximum transfer power of the interconnection line where the optimal interconnection switch is located is less than the power load power of the non-fault section, restore power in stages until there are no more restorable areas. Step 5.3 specifically includes:

[0147] Step 5.3.1: Determine the unrecoverable section based on the power restoration capacity constraint and remove the unrecoverable section.

[0148] The power restoration capacity constraints are:

[0149] (10)

[0150] Where, is the load capacity during period t, is the maximum transfer power of interconnection line n.

[0151] Step 5.3.2: Close the optimal tie switch and update the load capacity and restorable capacity of the unrestored section.

[0152] Preferably, when there is communication, updating the load capacity and the restorable capacity of the unrestored section in stages includes:

[0153] Update the load capacity of the unrecovered section as follows:

[0154] (11)

[0155] Where, is the load capacity during period t, that is, the load capacity of the unrestored section. is the power sum of the power loss load in the non-fault section, is the load power of interconnection line n before transfer, A collection of sections where power supply has been restored.

[0156] Step 5.3.3: Connect the grid-connected DG and update the restorable capacity.

[0157] Based on the source-load balance constraint, the optimal tie switch is closed and other tie switches are locked. The recoverable capacity of the tie switch remaining capacity is updated as follows:

[0158] (12)

[0159] Where, For recoverable capacity, This is a collection of restored power supply sections. is the maximum transfer power of the interconnection line n, is the active power of the grid-following distributed power supply in the non-fault power-off section connected to the island area before the fault. It is the ratio of pre-fault active power that can be output within the preset time period when the voltage at the common connection point reaches the normal operating range.

[0160] Step 5.3.4: Update the power and load power of the non-fault section. Determine whether to restore power in sections based on the updated power and load power of the non-fault section and the updated recoverable capacity. Repeat steps 5.3.1 to 5.3.4 until there are no recoverable areas.

[0161] Step 5.4: When the adjacent section of the island is restored, the switches connected to the island area and the area restored by the tie breaker closing are synchronized and connected to the grid.

[0162] Step 6: When the power supply is restored to the adjacent section of the island, the switches connected to the island area and the tie switch closing restoration area are synchronized and connected to the grid, and power supply is restored to the remaining loads in the island according to the load power supply restoration sequence and the updated restorable capacity.

[0163] Synchronous grid connection check means that during the grid connection operation, the voltage amplitude, frequency and phase angle on both sides of the grid connection point are detected to see if they meet the synchronization conditions, so as to decide whether to close the switch to complete the grid connection.

[0164] In this embodiment, after load restoration is complete within the island, due to capacity limitations, some loads remain internally, while all external loads cannot be restored. At this point, the minimum restoration unit operates as an island. Because the tie switch is connected to the opposite power source, closing the tie switch provides power support, restoring power to some loads (depending on the capacity of the opposite power source). When the tie switch is closed, if the restored area is adjacent to the island, the connected switches will be closed synchronously.

[0165] like Figure 3 As shown, Figure 3 This is a typical multi-connection grid diagram for a distributed power source connected to the distribution network. Figure 3 In the 5G network, the self-healing integrated terminal can realize information exchange through 5G wireless communication. DG1, DG3, and DG4 are all grid-following DGs with rated output capacities of 2MW, 3MW, and 2MW respectively. DG2 is a grid-forming DG with a rated output capacity of 2MW. The maximum transfer power of the tie switches LSW1 and LSW2 are 4.5MW and 4MW respectively. Taking the fault between the main line section switches FS1 and FS2 as an example, the phased power supply restoration steps are as follows:

[0166] Step 1: The self-healing terminal obtains a signal indicating successful isolation of the faulty section and determines the power-off area.

[0167] The fault point is located in the minimum restoration unit 2, and the power-off area is the minimum restoration unit 3-9; the node information includes DG1, DG3, and DG4, which are all network-following DGs, and DG2 is a network-forming DG.

[0168] Specifically, the main line section switches FD1 and FD2 and the branch switch FS1 trip due to protection action, completing the isolation of the fault section.

[0169] Step 2: Cut off all grid-connected distributed power sources in the power-off area that are connected to the node that receives the isolation success signal.

[0170] The switches YS1, YS3, and YS4 at the connection between the grid-following types DG1, DG3, and DG4 in the non-fault power-off area and the system will actively trip after receiving the fault isolation success signal, and DG1, DG3, and DG4 will be disconnected from the grid.

[0171] Step 3: Since the power outage area includes the grid-type DG2 node, a planned island is constructed based on the source-load balance condition. Within each planned island, the load power supply restoration order is determined according to the load level, and the minimum restoration unit with the highest load level is restored first.

[0172] Step 3.1: Update the minimum restoration unit load power according to formula (1) based on the section information at the time of fault. The section information at the time of fault includes DG power, load power, tie switch capacity, etc. The calculation results are shown in Table 2.

[0173] Table 2

[0174]

[0175] Step 3.2: When the load is greater than the minimum restoration unit load power, the load power supply restoration order is determined according to the total power supply load capacity, load level and corresponding constraints of different loads in the preset time period.

[0176] Figure 3 In the figure, the total load power of the minimum recovery unit 8 is 2MW, which meets the constraint condition (2) that it is not greater than the rated capacity of the grid-type DG2. The branch switch FS2 trips, and the minimum recovery unit 8 operates in an island mode, which means that the load in the minimum recovery unit is restored.

[0177] Figure 3 Since there is a communication grid, skip step 4 and proceed to step 5.

[0178] Step 5: When the power-off area is connected to other areas of the distribution network, the optimal tie switch is determined based on the tie line and the power of the power-off load. After the irrecoverable section is cut off, the optimal tie switch is closed. Based on the capacity of the adjacent grid-following DG, power is restored in stages by cyclically cutting off the irrecoverable load, connecting the grid-following DG, and updating the restorable capacity until there are no more restorable sections. When the power is restored to the adjacent section of the island, the switches connected to the island area and the area restored by closing the tie switch are synchronized and connected to the grid.

[0179] Step 5.1: Calculate the maximum restoration capacity of the maximum transfer power of tie line 1 and tie line 2 respectively, and select the tie switch LSW2 with the maximum restoration capacity as the optimal tie switch. The specific comparison method is as follows:

[0180] ,

[0181] ,

[0182] ,

[0183] Where, is the maximum recovery capability of the maximum transfer power of the interconnection line 1, The maximum recovery capability of the maximum transfer power of the interconnection line 2.

[0184] Step 5.2: Update the power sum of the power loss load in the non-fault section according to formula (9):

[0185] ,

[0186] Step 5.3: When the maximum restoration capacity of the maximum transfer power of the interconnection line where the optimal interconnection switch is located is less than the power of the power loss load in the non-fault section, restore power in stages until there are no more restorable areas.

[0187] because Greater than Therefore, it is impossible to restore all non-fault power-off areas at once. Step 5.3 specifically includes:

[0188] Step 5.3.1: Determine the unrecoverable section based on the power restoration capacity constraint and remove the unrecoverable section.

[0189] Specifically, according to formula (10), we can get:

[0190] ,

[0191] It can be seen that since the sum of the load capacities of the minimum restoration unit 5 and the minimum restoration unit 9 is less than the maximum transfer power of the interconnection line 2, the sum of the load capacities of the minimum restoration unit 4, the minimum restoration unit 5 and the minimum restoration unit 9 is greater than the maximum transfer power of the interconnection line 2. Therefore, the main line section switch FD4 is opened to cut off the minimum restoration units 4 and 7 in the section that cannot be restored to meet the power supply restoration capacity constraint.

[0192] Step 5.3.2: Close the optimal tie breaker and update the load capacity of the unrestored section.

[0193] Specifically, the tie switch LSW2 is closed and the tie switch LSW1 is locked to prevent the two tie switches from closing at the same time. The closed loop operation may cause asynchronous closing. The power supply of the minimum recovery units 5 and 9 is restored, and the load capacity of the unrestored section is updated according to formula (11):

[0194] ,

[0195] Step 5.3.3: Connect the grid-connected DG and update the restorable capacity.

[0196] Branch switch YS4 is closed, DG4 is connected to the grid and outputs power. The recoverable capacity is updated according to formula (12):

[0197] ,

[0198] Step 5.3.4: Update the power and load power of the non-fault section. Determine whether to restore power in sections based on the updated power and load power of the non-fault section and the updated recoverable capacity. Repeat steps 5.3.1 to 5.3.4 until there are no recoverable areas.

[0199] Because the total load capacity of the unrestored sections 3, 4, and 7 is 4MW, which is greater than the restorable capacity, it is impossible to restore all non-fault power outage areas at once. The main line section switch FD3 is opened to remove the smallest restoration unit 3 in the unrestored section, meeting the power restoration capacity constraint:

[0200] ,

[0201] Then, the main line section switch FD4 is closed, power supply to the minimum restoration units 4 and 7 is restored, and the load capacity of the unrestored section is updated:

[0202] ,

[0203] Then, branch switch YS3 is closed, DG3 is connected to the grid and outputs power, and the recoverable capacity is updated: ,

[0204] Then, in the non-fault power outage area, only the smallest restoration unit 3 remains without power restoration, satisfying the power restoration capacity constraint:

[0205] ,

[0206] Then, the main line section switch FD3 is closed, the power supply of the minimum restoration unit 3 is restored, and the power supply to all loads in the power-lost area is restored.

[0207] Step 6: Check the synchronization of the switch FS2 connecting the island to the system and close it, and then restore the power supply process technology.

[0208] Embodiment 2 of the present invention provides a distribution network power restoration system that takes into account the coordination of multiple types of distributed power sources, and runs the distribution network power restoration method that takes into account the coordination of multiple types of distributed power sources as described in embodiment 1. The system includes:

[0209] Determination module, used to obtain the fault section isolation success signal and determine the power failure area;

[0210] A cut-off module is used to cut off all grid-connected distributed power sources connected to the nodes that have received the isolation success signal in the power-off area;

[0211] A construction module is used to construct planned islands when the power outage area contains grid-type distributed power generation nodes. Within each planned island, the load power supply restoration order is determined based on the load level, and the minimum restoration unit with the highest load level is restored first.

[0212] The first restoration module is used to detect the status of the no-voltage reclosing switch upstream of the fault point when there is no communication between the power outage area and other areas of the distribution network, and determine the power supply restoration strategy based on the fault type and the status of the no-voltage reclosing switch;

[0213] The second restoration module is used to determine the optimal tie switch based on the tie line and the power of the power-lost load when the power-lost area is connected to other areas of the distribution network. After removing the unrecoverable section, the optimal tie switch is closed. Based on the capacity of adjacent grid-connected distributed power sources, power is restored in stages by cyclically removing unrecoverable loads, connecting grid-connected distributed power sources, and updating the recoverable capacity until there are no more recoverable sections.

[0214] The third recovery module is used to synchronize the switches connected to the island area and the tie switch closing recovery area when the recovery is to the adjacent section of the island, and restore power to the remaining loads in the island according to the load power supply recovery sequence and the updated restorable capacity.

[0215] Regarding the system in the above embodiment, the specific manner in which each unit performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0216] Embodiment 3 of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, the method for restoring power supply to a distribution network taking into account the coordination of multiple types of distributed power sources described in embodiment 1 is implemented.

[0217] In some embodiments, the electronic device may be a self-healing integrated terminal.

[0218] Embodiment 4 of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements a distribution network power supply restoration method taking into account the coordination of multiple types of distributed power sources according to embodiment 1.

[0219] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0220] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0221] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0222] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0223] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all protected by the present invention.

Claims

1. A method for power distribution network restoration taking into account the coordination of multiple types of distributed power sources, characterized in that: include: Obtain the fault section isolation success signal and determine the power failure area; Cut off all grid-connected distributed power sources in the power-off area that are connected to the node that receives the isolation success signal; When the power outage area includes a grid-type distributed power generation node, a planned island is constructed, and the load power supply restoration order is determined according to the load level within each planned island, and the minimum restoration unit with the highest load level is restored first; wherein the planned island includes multiple minimum restoration units, and the load power supply restoration order is determined according to the load level within each planned island, including: calculating the load power of each minimum restoration unit; when the load is greater than or equal to the load power of the minimum restoration unit, the load power supply restoration order is determined according to the total power supply load capacity of different loads in a preset time period, the load level and the corresponding constraints; When the power outage area is disconnected from other areas of the distribution network, the system detects the status of the no-voltage reclosing switch upstream of the fault point and determines the power restoration strategy based on the fault type and the no-voltage reclosing status. When the power outage area is connected to other areas of the distribution network, the optimal tie switch is determined based on the tie line and the power of the power-lost load. After the non-recoverable section is cut off, the optimal tie switch is closed. Based on the capacity of the adjacent grid-type distributed power sources, the non-recoverable load is cyclically cut off, the grid-type distributed power sources are connected to the grid, and the recoverable capacity is updated. After the grid-type distributed power sources are connected to the grid and the recoverable capacity is updated, the power of the power-lost load in the non-fault section is updated. Based on the updated power-lost load power in the non-fault section and the updated recoverable capacity, it is determined whether to restore power in stages, and the staged restoration is achieved until there are no more recoverable sections. The optimal tie switch is determined based on the tie line and the power of the power-lost load, including: calculating the recoverable capacity of the grid-connected distributed power source connected to the island after being connected to the grid; calculating the maximum transfer power of each tie line before power is restored; calculating the maximum recovery capability of the maximum transfer power of each tie line based on the recoverable capacity and the maximum transfer power of each tie line before power is restored, and determining the optimal tie switch based on the maximum recovery capability of the maximum transfer power of each tie line; And update the recoverable capacity as follows: ， Where, For recoverable capacity, This is a collection of restored power supply sections. is the maximum transfer power of the interconnection line n, is the active power of the grid-following distributed power supply in the non-fault power-off section connected to the island area before the fault. The ratio of pre-fault active power that can be output within a preset time period when the voltage at the common connection point reaches the normal operating range; When the power supply is restored to the adjacent section of the island, the switches connected to the island area and the area restored by the tie switch are synchronized and connected to the grid, and power supply to the remaining loads in the island is restored according to the load power supply restoration sequence and the updated restorable capacity.

2. The method for power distribution network restoration taking into account the coordination of multiple types of distributed power sources according to claim 1, characterized in that: The constraint condition of the total power supply load capacity of the load in the preset time period is that the total power supply load capacity of the load in the preset time period is less than the capacity of the grid-forming distributed power supply. The load power supply restoration order is determined based on the total power supply load capacity of the preset time period of different loads, the load level and the corresponding constraint conditions, including: The load is divided according to the sum of the capacity of the grid-type distributed power sources and the constraint condition of the total capacity of the power supply load in the preset time period of the load to obtain multiple load sets; Determine the load power supply sequence according to load level among multiple load concentrations, and allocate restorable load capacity according to load level.

3. The method for power distribution network restoration taking into account the coordination of multiple types of distributed power sources according to claim 1, characterized in that: The power restoration strategy includes transient faults and permanent faults.

4. The method for power distribution network restoration taking into account the coordination of multiple types of distributed power sources according to claim 1, characterized in that: The maximum restoration capability of the maximum transfer power of each tie line is calculated based on the restorable capacity and the maximum transfer power of each tie line before power restoration. The optimal tie switch is determined based on the maximum restoration capability of the maximum transfer power of each tie line, including: The maximum restoration capacity of the maximum transfer power of each tie line is obtained by summing the restorable capacity and the maximum transfer power of each tie line before power restoration. The tie line corresponding to the maximum value among the maximum restoration capabilities is selected as the optimal tie switch.

5. The method for power distribution network restoration taking into account the coordination of multiple types of distributed power sources according to claim 1, characterized in that: The method further comprises: Based on the power supply restoration capacity constraint condition, it is determined whether there is a restorable section, and the power supply restoration capacity constraint condition is that the load capacity in a preset time period is less than or equal to the maximum transfer power of the interconnection line.

6. A distribution network power supply restoration system taking into account the coordination of multiple types of distributed power sources using the distribution network power supply restoration method taking into account the coordination of multiple types of distributed power sources according to any one of claims 1 to 5, characterized in that: The system comprises: Determination module, used to obtain the fault section isolation success signal and determine the power failure area; A cut-off module is used to cut off all grid-connected distributed power sources connected to the nodes that have received the isolation success signal in the power-off area; A construction module is used to construct planned islands when the power outage area contains grid-type distributed power generation nodes. Within each planned island, the load power supply restoration order is determined based on the load level, and the minimum restoration unit with the highest load level is restored first. The planned island includes multiple minimum restoration units. The load power supply restoration order is determined according to the load level in each planned island, including: calculating the load power of each minimum restoration unit; when the load is greater than or equal to the load power of the minimum restoration unit, determining the load power supply restoration order according to the total power supply load capacity, load level and corresponding constraints of different loads in the preset time period; The first restoration module is used to detect the status of the no-voltage reclosing switch upstream of the fault point when there is no communication between the power outage area and other areas of the distribution network, and determine the power supply restoration strategy based on the fault type and the status of the no-voltage reclosing switch; The second recovery module is used to determine the optimal tie switch according to the tie line and the power of the power-lost load when the power-lost area is connected to other areas of the distribution network, close the optimal tie switch after cutting off the non-recoverable section, and based on the capacity of the adjacent grid-type distributed power sources, cyclically cut off the non-recoverable load, connect the grid-type distributed power sources to the grid, and update the recoverable capacity. After the grid-type distributed power sources are connected to the grid and the recoverable capacity is updated, the power of the power-lost load in the non-fault section is updated, and the updated non-fault section power-lost load and the updated recoverable capacity are used to determine whether to restore power in stages according to the updated non-fault section power-lost load and the updated recoverable capacity, so as to achieve staged power restoration until there are no more recoverable sections; The optimal tie switch is determined based on the tie line and the power of the power-lost load, including: calculating the recoverable capacity of the grid-connected distributed power source connected to the island after being connected to the grid; calculating the maximum transfer power of each tie line before power is restored; calculating the maximum recovery capability of the maximum transfer power of each tie line based on the recoverable capacity and the maximum transfer power of each tie line before power is restored, and determining the optimal tie switch based on the maximum recovery capability of the maximum transfer power of each tie line; And update the recoverable capacity as follows: ， Where, For recoverable capacity, This is a collection of restored power supply sections. is the maximum transfer power of the interconnection line n, is the active power of the grid-following distributed power supply in the non-fault power-off section connected to the island area before the fault. The ratio of pre-fault active power that can be output within a preset time period when the voltage at the common connection point reaches the normal operating range; The third recovery module is used to synchronize the switches connected to the island area and the tie switch closing recovery area when the recovery is to the adjacent section of the island, and restore power to the remaining loads in the island according to the load power supply recovery sequence and the updated restorable capacity.

7. An electronic device comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method for power supply restoration in a distribution network taking into account the coordination of multiple types of distributed power sources according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the distribution network power supply restoration method taking into account the coordination of multiple types of distributed power sources as described in any one of claims 1 to 5 are implemented.

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