Microgrid system source detection method, system and equipment

Abstract

The invention provides a micro-grid system source detection method, system and device, and relates to the technical field of power grids, and the method comprises the steps: responding to a line state collection instruction through a plurality of substations, respectively collecting the electrical quantity of a preset key line, the position of a split-phase switch and a protection tripping signal, judging the line switching and tripping states, and obtaining a detection result; the state information is sent to a master control station, so that the master control station performs processing based on the state information in combination with electrical quantities, switch positions and protection tripping signals, collected by the station, of the high-voltage side and the medium-voltage side of a main transformer and a tie line, and a processing result is obtained; the load control station receives the processing result and acquires the electrical quantity and switch position information of the tie line, the high and low voltage side of the main transformer and the energy storage line to obtain the small island state; and the master control station generates a result containing the states of the large island, the medium island and the total island based on the state of the small island. According to the scheme, the self-healing capability and the operation stability of the micro-grid in an off-grid scene can be improved.

Description

Technical Field

[0001] The present invention relates to the field of power grid technology, and in particular to a method, system and device for detecting a source of a microgrid system. Background Art

[0002] Traditional island detection methods mainly rely on local electrical quantity monitoring (such as voltage / frequency offset, harmonic changes) or communication signal interruption judgment; for example, passive detection judges off-grid by monitoring sudden changes in voltage amplitude and frequency, but is easily affected by load fluctuations and changes in distributed power output, and has a high misjudgment rate; active detection observes the response by injecting disturbance signals, which may affect the power quality and is difficult to adapt to complex microgrids with multiple power sources and multi-level structures; in addition, existing technologies are mostly limited to the status judgment of a single node and lack real-time analysis of the global topology of the microgrid, resulting in the inability to accurately distinguish between multiple levels of states such as large islanding (complete disconnection of the main grid), medium islanding (partial disconnection of the medium-voltage busbar) and small islanding (independent operation of the load side) in complex network structures, which in turn affects the accuracy of the control strategy. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method, system and device for detecting the source of a microgrid system, which can improve the self-healing ability and operational stability of the microgrid in an off-grid scenario.

[0004] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0005] The present invention provides a method for detecting a source of a microgrid system, the method comprising:

[0006] Collect electrical quantities and switch position information of each bay of multiple substations in the microgrid system;

[0007] Performing a global topology analysis based on the electrical quantity and switch position information to obtain a topology analysis result;

[0008] Based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals and the fault electrical quantities, the grid connection or disconnection status of the microgrid system and the external grid is identified;

[0009] Based on the grid-connected or off-grid status, when an unplanned off-grid event is detected in the microgrid, the unplanned off-grid control strategy is triggered and line status collection instructions are sent to multiple substations;

[0010] Multiple substations respond to line status collection instructions, respectively collecting electrical quantities, phase switch positions, and protection trip signals of preset key lines, determining line shutdown and tripping status, and obtaining status information;

[0011] The status information is sent to the master control station, so that the master control station processes the status information based on the electrical quantities of the high-voltage side, medium-voltage side and tie line of the main transformer, the switch position and the protection trip signal collected by the master control station to obtain a processing result;

[0012] The load control station receives the processing results and collects the electrical quantities and switch position information of the tie line, the high and low voltage sides of the main transformer, and the energy storage line to obtain the small island status;

[0013] Based on the small island status, the master control station generates results including large island status, medium island status and total island status.

[0014] Optionally, performing a global topology analysis based on the electrical quantity and the switch position information to obtain a topology analysis result includes:

[0015] Based on the electrical quantities collected by each substation, the voltage and current correlation between each node in the microgrid system is determined. Combined with the closed / open status of the phase switches in the switch position information, a dynamic topology connection matrix is ​​constructed.

[0016] Analyzing the electrical connectivity path according to the dynamic topology connection matrix, and determining that the current branch is removed from the global topology when the electrical quantity of the branch returns to zero and the corresponding switch position is in an open state;

[0017] The branch removal status of each substation is integrated to generate a topology analysis result that reflects the current electrical connection relationship of the microgrid system.

[0018] Optionally, based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities, identifying the grid-connected or off-grid status of the microgrid system and the external grid includes:

[0019] Based on the main network connection point status in the topology analysis result, if the electrical quantity at the main network connection point is continuously non-zero and the switch position is closed, it is determined to be in a grid-connected state;

[0020] When it is detected that the electrical quantity at the main grid connection point suddenly drops to zero, and the protection device action signal is triggered or the switch change signal indicates disconnection, combined with the sudden change characteristics of the fault electrical quantity, it is determined to be an off-grid state;

[0021] When an off-grid state occurs without receiving a planned off-grid instruction, it is marked as an unplanned off-grid event.

[0022] Optionally, multiple substations respond to line status collection instructions, respectively collecting electrical quantities, phase switch positions, and protection trip signals of preset key lines, determining the line's shutdown and tripping status, and obtaining status information, including:

[0023] Each substation analyzes the line status acquisition instruction issued by the master control station, determines the target line and the parameters to be collected, calls the local measurement and control device to perform synchronous sampling on the designated line, and collects the phase-by-phase electrical quantities of the preset key line;

[0024] Collect phase switch positions and protection trip signals, perform switch status logic judgment, and obtain switch / protection signal verification results;

[0025] Based on the electrical quantity acquisition results and the switch / protection signal verification results, the line status is judged to obtain the line status judgment result;

[0026] Based on the line status judgment results, status information including line name, timestamp, phase switch position, electrical quantity status label and trip type is generated.

[0027] Optionally, the status information is sent to a master control station, so that the master control station processes the status information based on the information and in combination with the electrical quantities, switch positions, and protection trip signals of the main transformer high-voltage side, medium-voltage side, and tie lines collected by the station to obtain a processing result, including:

[0028] The master control station receives the preset key line shutdown and tripping status sent by multiple substations. Combined with the sudden changes in electrical quantities on the high-voltage side, medium-voltage side, and tie lines collected by the master control station, it determines whether the high-voltage side of the main transformer is disconnected from the external system:

[0029] If the current on the high-voltage side of the main transformer suddenly drops to zero and the corresponding switch position is disconnected, a large islanding determination result is generated;

[0030] If the bus voltage on the medium voltage side of the main transformer suddenly drops to zero and the tie line switch is disconnected, the islanding determination result is generated;

[0031] If the electrical quantity of the tie line returns to zero and the protection trip signal is triggered, the tie line disconnection judgment result is generated.

[0032] Optionally, the load control station receives the processing results and collects electrical quantities and switch position information on the tie line, high and low voltage sides of the main transformer, and energy storage line to obtain the small island status, including:

[0033] The load control station receives the tie line decoupling judgment result sent by the master control station, and simultaneously collects the tie line current, voltage and energy storage line power direction of the station;

[0034] If the tie line current is zero and the energy storage line power is transmitted from the energy storage to the load side, then the local switch position information is combined to determine whether the load side is isolated from the main grid;

[0035] When the load-side electrical quantity is supported only by energy storage and local power supply, it is determined to be a small island state and the state is fed back to the master control station.

[0036] Optionally, the master station generates results based on the small island status, including large island, medium island, and total island status, including:

[0037] The master control station receives the small islanding status feedback from the load control station. If the large islanding determination result is valid, the overall islanding status is marked as large islanding.

[0038] If the medium island determination result is valid and the large island mark is invalid, the overall island status is marked as medium island;

[0039] If only a small islanding state exists and the local judgment criteria of the master control station confirm that the load side is operating independently, the total islanding state is marked as a small islanding state, and the final output is a three-level hierarchical judgment result of large islanding, medium islanding and total islanding state.

[0040] An embodiment of the present invention further provides a microgrid system source detection system, comprising:

[0041] An acquisition module is used to collect electrical quantities and switch position information of each interval of multiple substations in the microgrid system, perform global topology analysis based on the electrical quantities and switch position information, and obtain a topology analysis result;

[0042] an identification module for identifying the grid-connected or off-grid status of the microgrid system and the external grid based on the topology analysis results and in combination with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities;

[0043] The sending module is used to trigger the unplanned off-grid control strategy and send line status collection instructions to multiple substations based on the grid-connected or off-grid status when an unplanned off-grid event is detected in the microgrid;

[0044] The processing module is used to respond to the line status collection instruction through multiple substations, collect the electrical quantities, phase switch positions and protection tripping signals of preset key lines respectively, determine the line shutdown and tripping status, and obtain status information; send the status information to the main control station, so that the main control station processes the status information based on the status information and the electrical quantities, switch positions and protection tripping signals of the main transformer high-voltage side, medium-voltage side and tie line collected by the station to obtain processing results; receive the processing results through the load control station, and collect the electrical quantities and switch position information of the tie line, the high- and low-voltage sides of the main transformer and the energy storage line to obtain the small island status; generate the results including large island, medium island and total island status based on the small island status through the main control station.

[0045] An embodiment of the present invention further provides a computing device, comprising: a processor and a memory storing a computer program, wherein the computer program executes the above-mentioned method when executed by the processor.

[0046] An embodiment of the present invention further provides a computer-readable storage medium, comprising: storing instructions, which, when executed on a computer, enable the computer to execute the above-mentioned method.

[0047] The above solution of the present invention includes at least the following beneficial effects:

[0048] The detection method of the microgrid system source of the present invention collects the electrical quantities and switch position information of each interval of multiple substations in the microgrid system; performs global topology analysis based on the electrical quantities and switch position information to obtain topology analysis results; based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals and the fault electrical quantities, identifies the grid-connected or off-grid status of the microgrid system and the external grid; based on the grid-connected or off-grid status, when it is identified that the microgrid is unplanned off-grid, triggers the unplanned off-grid control strategy and sends line status collection instructions to multiple substations; and responds to the line status collection instructions through multiple substations. The system collects electrical quantities, phase switch positions, and protection trip signals from preset key lines, determines the line's shutdown and tripping status, and obtains status information. This information is then sent to the master control station, which processes the status information based on the electrical quantities, switch positions, and protection trip signals collected from the high- and medium-voltage sides of the main transformer and the tie lines, to obtain a processing result. The load control station receives the processing result and collects electrical quantities and switch position information from the tie lines, high- and low-voltage sides of the main transformer, and energy storage lines to obtain a small islanding status. Based on the small islanding status, the master control station generates a result including large islanding, medium islanding, and total islanding status. This can improve the self-healing capability and operational stability of the microgrid in off-grid scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 1 is a flow chart of a method for detecting a source of a microgrid system according to the present invention;

[0050] Figure 2 It is a module schematic diagram of the detection system of the microgrid system source of the present invention. DETAILED DESCRIPTION

[0051] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0052] like Figure 1 As shown, an embodiment of the present invention provides a method for detecting a source of a microgrid system, which is applied to a source-grid-load-storage microgrid system. The method includes:

[0053] Step 11, collecting electrical quantities and switch position information of each interval of multiple substations in the microgrid system;

[0054] Step 12: performing a global topology analysis based on the electrical quantity and the switch position information to obtain a topology analysis result;

[0055] Step 13: Based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities, identify the grid connection or disconnection status of the microgrid system and the external grid;

[0056] Step 14: Based on the grid-connected or off-grid status, when an unplanned off-grid event is detected in the microgrid, an unplanned off-grid control strategy is triggered, and a line status collection instruction is sent to multiple substations;

[0057] Step 15: Multiple substations respond to the line status collection instruction, respectively collect the electrical quantities, phase switch positions, and protection trip signals of the preset key lines, determine the line shutdown and trip status, and obtain status information;

[0058] Step 16: Send the status information to the master control station, so that the master control station processes the status information based on the electrical quantities, switch positions, and protection trip signals of the main transformer high-voltage side, medium-voltage side, and tie line collected by the station to obtain a processing result;

[0059] Step 17: Receive the processing results through the load control station, collect the electrical quantities and switch position information of the tie line, the high and low voltage sides of the main transformer, and the energy storage line, and obtain the small island status;

[0060] In step 18, the master control station generates a result including a large island, a medium island, and a total island status based on the small island status.

[0061] In this embodiment, by collecting the electrical quantities and switch position information of each substation in real time, a dynamic topology connection matrix is ​​constructed, and the global topology structure is quickly updated in combination with graph theory algorithms, which significantly improves the adaptability to changes in the operation mode of the microgrid and avoids the misjudgment problem caused by the traditional fixed topology model; based on the collaborative data interaction between the master station and the substation, the protection device action signal, switch position change signal and the sudden change characteristics of the fault electrical quantity are integrated to quickly distinguish between multiple levels of states such as large islanding (complete disconnection of the main grid), medium islanding (disconnection of the medium-voltage busbar) and small islanding (independent operation of the load side), providing a reliable basis for hierarchical control. By triggering the unplanned off-grid control strategy, linking multiple substations to collect key line status information, combined with the master station's real-time monitoring of the high-voltage side, medium-voltage side and connecting line of the main transformer, fault location and islanding judgment are completed within milliseconds, greatly shortening the control response time. The load control station dynamically cuts off non-critical load switches based on the instructions of the master control station and local criteria, avoiding over-cutting or under-cutting problems caused by traditional single control strategies. At the same time, it combines the power direction of the energy storage line to achieve autonomous maintenance of the small island state and improve power supply reliability. It adopts a collaborative communication mechanism between the master control station and the substation, outputs the island state through hard contacts and uses the GOOSE protocol to transmit and disconnect information, ensuring real-time performance while reducing the amount of communication data and lowering the risk of control failure due to communication delays or interruptions.

[0062] In an optional embodiment of the present invention, in step 12, performing a global topology analysis based on the electrical quantity and the switch position information to obtain a topology analysis result may include:

[0063] Step 121: Based on the electrical quantities collected by each substation, determine the voltage and current correlation between each node in the microgrid system, and build a dynamic topology connection matrix based on the closed / open status of the phase switches in the switch position information;

[0064] Step 122: Analyze electrical connectivity paths using a graph theory algorithm based on the dynamic topology connection matrix. When the electrical quantity of a branch returns to zero and the corresponding switch position is disconnected, determine that the current branch is removed from the global topology.

[0065] Step 123 , integrating the branch removal status of each substation to generate a topology analysis result reflecting the current electrical connection relationship of the microgrid system; the topology analysis result includes the real-time topology structure of the main grid connection point, tie line and energy storage node.

[0066] In this embodiment, the node voltage amplitude, phase and line current direction collected by each substation are compared to determine whether there is an electrical connection between the nodes (for example, if the voltage difference between adjacent nodes is less than a threshold and the current flow direction conforms to Kirchhoff's law, it is considered to be associated). The phase state (A / B / C phase closed / open) in the switch position information is converted into a matrix element: the closed phase is recorded as "1" and the open phase is recorded as "0". For example: if the A phase of a switch is closed and the B / C phase is open, the A phase element of the branch in the corresponding matrix is ​​1, and the B / C phase is 0. With the nodes as rows / columns, based on the electrical correlation and the phase state of the switch, an N×N dynamic matrix (N is the number of nodes) is generated, and the element value reflects the phase connectivity between the corresponding nodes (for example, the matrix element M[i,j]=[1,0,1] indicates that the A phase and C phase are connected and the B phase is open between the ij nodes). The present invention reflects the switch phase operation (such as single-phase tripping after a single-phase grounding fault) and electrical quantity changes in real time, and incorporates the phase state into the topology analysis, which can accurately identify local topology changes after an asymmetric fault (such as a two-phase short circuit); traverse the dynamic matrix, if the three-phase electrical quantities of a branch (i, j) are all zero (such as current and power are zero), and the corresponding switch phase states are all disconnected (all matrix elements are 0), then the branch is marked as "to be removed"; exception processing: if the electrical quantity is zero but the switch is closed (such as an unloaded line), the branch is retained (considered to be unloaded and connected); using the connectivity analysis algorithm in graph theory (such as breadth-first search BFS or depth-first search DFS), starting from the main network connection point, traverse the "1" elements in the matrix to identify valid electrical paths, for example: if the main network connection point is node S, through BFS it is found that node S cannot reach node T through any "1" element path, then it is determined that the branch where node T is located is disconnected from the main network; for the branch marked as "to be removed", if it is not in any valid electrical path, Remove it from the topology; if there are still other phases connected (such as phase A is closed, phase B / C is disconnected but the electrical quantity of phase A is non-zero), then the phase branch is retained. In this embodiment, the no-load state of "switch disconnected but the electrical quantity is non-zero" is distinguished from the real disconnection state of "switch disconnected and the electrical quantity is zero" to avoid misjudgment (such as the no-load line is misjudged as the fault removal). The connection path is updated in real time through the graph theory algorithm to adapt to the dynamic topology changes caused by the switching of distributed power sources in the microgrid (such as the access / exit of energy storage nodes); collect the tags of each substation The "branch to be removed" list is removed from the list. Branches that are still globally connected (e.g., connected via other substations) due to local faults (e.g., a switch tripped inside the substation) are removed. For example, if substation X reports a branch disconnected, but the master control station finds that the branch is still connected via the path to substation Y based on data from substation Y, then the branch is not included in the global removal list. The real-time connectivity status of the main grid connection points (e.g., nodes on the high-voltage side of the main transformer), tie line nodes (nodes connecting different substations), and energy storage nodes (e.g., energy storage converter access points) is marked:

[0067] Main grid connection point: If it is associated with the external grid electrical quantity (such as the voltage and frequency are consistent with the main grid), it is marked as "grid-connected state"; otherwise, it is marked as "off-grid state";

[0068] Tie line node: If it is connected with other substation nodes, it is marked as "interconnected state"; otherwise, it is marked as "isolated state";

[0069] Energy storage node: If it is in the discharging state (current flows out of the node), it is marked as "power supply state"; if it is in the charging state, it is marked as "load state";

[0070] Output the topology in graphical or list form, marking each node type (main network / interconnection line / energy storage), connectivity status (connected / disconnected) and phase information (such as A connected, B / C disconnected).

[0071] The present invention avoids the limitations of single-substation data and ensures the accuracy of topology analysis results through cross-validation of multi-station data (for example, when a branch is disconnected at substation A but connected at substation B, the actual electrical path shall prevail). The status of the main network connection point can be determined to quickly judge and disconnect from the grid, and the power supply status of the energy storage node can be marked to assist in load control strategies (for example, priority is given to retaining loads in island areas powered by energy storage).

[0072] In an optional embodiment of the present invention, step 13, based on the topology analysis results and in combination with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities, identifying the grid-connected or off-grid status of the microgrid system and the external grid may include:

[0073] Step 131: Based on the main network connection point status in the topology analysis result, if the electrical quantity at the main network connection point is continuously non-zero and the switch position is closed, it is determined to be in a grid-connected state;

[0074] Step 132: When it is detected that the electrical quantity at the main grid connection point suddenly drops to zero and the protection device action signal is triggered or the switch change signal indicates disconnection, combined with the sudden change characteristics of the fault electrical quantity, it is determined to be an off-grid state;

[0075] Step 133: If no planned off-grid instruction is received when the off-grid state occurs, it is marked as an unplanned off-grid event.

[0076] In this embodiment, the state of the main grid connection point (such as the node on the high-voltage side of the main transformer) is extracted from the topology analysis results, and the electrical quantities (voltage, current, power, etc.) of the node and the corresponding switch position are continuously monitored. If the electrical quantity at the main grid connection point is continuously non-zero (indicating that energy is exchanged with the external grid) and the switch position is closed (the physical connection is not disconnected), it is determined that the microgrid is in the grid-connected state.

[0077] Off-grid status determination:

[0078] When the electrical quantity at the main grid connection point is monitored to drop to zero (such as voltage, current drops to 0 or close to 0), a preliminary off-grid early warning is triggered; protection device action signal: whether there is an overcurrent, overvoltage and other fault protection signal triggering (indicating that off-grid may be caused by failure);

[0079] Switching position signal: whether the switch corresponding to the main grid connection point changes from "closed" to "open" (physical connection is disconnected);

[0080] Fault electrical quantity mutation feature: such as current phase mutation, voltage frequency deviation from the main grid standard value (auxiliary judgment of fault type), if at least one of the above conditions is met (such as protection action and electrical quantity drop, or switch off and electrical quantity zero), it is determined that the off-grid state is reached; after determining the off-grid state, check whether the system receives a planned off-grid instruction (such as manual operation or preset program triggered off-grid command), if no planned instruction is received, mark it as a non-planned off-grid event, and trigger the subsequent control strategy (such as the non-planned off-grid response of step 3).

[0081] This embodiment combines topology state, electrical quantity change, protection signal and switch state, avoids single data misjudgment (such as relying only on switch position may misjudge the connection state due to contact failure), and through the linkage analysis of electrical quantity mutation feature (such as sudden drop, phase anomaly) and protection action, the off-grid reason (such as short circuit fault, switch misoperation) can be located in milliseconds, the off-grid nature (man-made plan or fault triggering) is determined, accurate basis is provided for subsequent control strategy (such as non-planned off-grid needs to start island control urgently, and planned off-grid can be switched orderly), state misjudgment caused by communication delay or single sensor failure is reduced, and the stability and safety of the micro-grid in the grid-connected and off-grid mode switching are ensured.

[0082] In an optional embodiment of the application, in step 14, based on the grid-connected or off-grid state, when it is identified that the micro-grid has a non-planned off-grid, a non-planned off-grid control strategy is triggered, and a line state acquisition instruction is sent to the plurality of sub-stations, which can include:

[0083] Step 141, based on the determination result of step 13, the electrical quantity (voltage / current / power) of the main grid connection point is checked again whether it is continuously zero, the consistency of the protection device action signal (such as overcurrent protection triggering) and the switch position signal (the main grid switch changes from "closed" to "open") is confirmed, and whether there is a planned off-grid instruction (such as manual operation record or system preset program triggering log) is verified.

[0084] Logical judgment, if "electrical quantity zero + protection action / switch off + no planned instruction" are met at the same time, it is formally marked as a non-planned off-grid event, and the subsequent control process is triggered.

[0085] Step 142, based on the topology analysis results generated in step 12, locate the key lines directly associated with the main network connection point (such as the main transformer high-voltage side incoming line, the main line of the tie line) and the corresponding substation nodes (such as the substation connected to the main network, the substation at both ends of the tie line); in the order of "main network connection point → tie line → energy storage access line", determine the line list that needs to be collected first (such as the main transformer high-voltage side line, the tie line across the substation, and the energy storage converter outgoing line), and associate it to the corresponding substation (such as substation A responsible for the main network incoming line, substation B and C responsible for the tie line section).

[0086] Step 143, generate customized collection instructions for each target substation, including:

[0087] Collection object: specify the name / number of key lines (such as "L1 main network incoming line" "L3 tie line A-B section");

[0088] Collection parameters: phase-by-phase electrical quantities (A / B / C phase voltage, current, power), phase-by-phase switch position (closed / open), protection tripping signal (whether overcurrent / quick-break protection is triggered);

[0089] Collection time limit: requires the substation to complete data collection and return within a millisecond period (such as 10ms).

[0090] Instruction distribution mechanism: send instructions to target substations through hard connection signals or GOOSE protocol to ensure real-time communication (reduce network delay impact), while using multi-path redundant communication (such as optical fiber + wireless) to improve instruction transmission reliability.

[0091] Step 144, local data collection, after the substation receives the instruction, immediately start the dedicated collection module, synchronously sample the electrical quantities of the specified line (ensure that the timestamps of each phase data are consistent), and read the switch position register and protection device action record.

[0092] Preliminary state discrimination: the substation locally preprocesses the data, marks abnormal states (such as sudden change of certain phase current to 3 times the rated value, switch position and electrical quantity contradiction), and compresses and packages the original data and discrimination results, ready to upload to the master station.

[0093] The present invention uses millisecond-level command triggering and data collection to achieve immediate response to unplanned off-grid events and shorten fault location time (traditional methods require second-level polling, which is improved to millisecond level here); targeted collection of key line status to avoid data flooding across the entire network, focus on suspected fault areas, and improve positioning accuracy (such as directly locking the main network incoming line or connecting line breakpoint); using multi-substation distributed collection to achieve cross-verification of the same line data (such as substation A collecting the main network side and substation B collecting the load side, and comparing to determine the line open and closed), avoiding misjudgment caused by single-site sensor failure; phase-split data collection supports asymmetric fault analysis (such as state identification of single-phase tripping after single-phase grounding), and improves the refinement of topology analysis.

[0094] In an optional embodiment of the present invention, in step 15, multiple substations respond to the line status collection instruction, respectively collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determine the line shutdown and trip status, and obtain status information, which may include:

[0095] Step 151: Each substation parses the line status collection instruction issued by the master control station, determines the target line and the parameters to be collected, and calls the local measurement and control device to synchronously sample the designated line to collect the phase-by-phase electrical quantities of the preset key line. Specifically, each substation parses the line status collection instruction issued by the master control station, determines the target line and the parameters to be collected, and calls the local measurement and control device to synchronously sample the designated line to collect the phase-by-phase electrical quantities of the preset key line, including voltage, current, frequency, and power direction of the energy storage line, and determines the line abnormality based on the comparison result of the electrical quantities with the rated values.

[0096] Step 152: collect the phase switch position and protection trip signal, perform switch state logic judgment, and obtain the switch / protection signal verification result. Specifically, based on the phase switch position and protection trip signal collected in step 151, perform switch state logic judgment:

[0097] Compare the switch position with the historical connectivity status of the line in the topology matrix to verify the consistency of the switch status;

[0098] In the scenario where the switch is closed but the electrical quantity is zero, the power factor is combined to determine whether it is a normal no-load state;

[0099] Verify the fault correlation of protection tripping signals based on protection device action records and electrical quantity mutation characteristics;

[0100] Step 153: Based on the electrical quantity collection results and the switch / protection signal verification results, a line state determination is performed to obtain a line state determination result. Specifically, based on the electrical quantity collection results of step 151 and the switch / protection signal verification results of step 152, the line state determination is performed:

[0101] When at least one phase of the phase-splitting switch is closed and the corresponding phase electrical quantity is non-zero, or when all switches are open but there is reverse power supply in the energy storage line, it is determined to be in operation state;

[0102] When all phase switches are disconnected and the electrical quantity is zero, or when the switches are closed but the electrical quantity is continuously zero and the power factor meets the no-load characteristics, it is determined to be in an outage state;

[0103] When the protection device action signal is triggered, the corresponding phase current drops to zero, and the switch position changes from closed to open, it is determined to be a protection trip; when the switch position changes to open but there is no protection action record, it is determined to be a non-protection trip;

[0104] Step 154: Generate status information including line name, timestamp, phase switch position, electrical quantity status label and trip type based on the line status judgment result. Specifically, integrate the line status judgment result of step 153 to generate status information including line name, timestamp, phase switch position, electrical quantity status label and trip type; add a warning label to the abnormal status and upload it to the master control station through the priority queue.

[0105] In this embodiment, after receiving the line status acquisition command from the master control station, the substation analyzes the target line list (e.g., "L1 main grid incoming line," "L5 energy storage outgoing line") and parameter requirements (phase electrical quantities, switch positions, protection signals), and calls the local measurement and control device to synchronously sample the specified line (with a sampling time difference of less than 1ms between each phase). Parameters such as phase voltage (e.g., phase RMS voltage of phase A), current (instantaneous value, power direction), and frequency are collected and compared with the rated values ​​to determine whether there are any anomalies (e.g., voltage sag > 30% of the rated value, current surge > 2 times the rated value). For energy storage lines, the power direction (current inflow / outflow node) is additionally monitored to determine whether the energy storage is in a charging or discharging state.

[0106] Switch state logic judgment:

[0107] Read the phase switch position register (A / B / C phase closed / open status) and compare it with the historical connectivity status of the line in the topology matrix (for example, if the instruction requires the switch to be in the closed state during acquisition, if a phase is actually disconnected, it is marked as abnormal); for the scenario of "the switch is closed but the electrical quantity is zero" (such as an unloaded line), determine whether it is a normal unloaded state through the power factor (close to 0) to avoid misjudging it as a fault disconnection.

[0108] Verify the protection tripping signal, check the protection device action record (such as whether the overcurrent I stage and quick-break protection are triggered), and combine the electrical quantity mutation characteristics (such as a sudden 180° change in current phase) to confirm whether the tripping is caused by a fault (rather than a false operation).

[0109] Investment and suspension status determination:

[0110] In the operational state, any of the following conditions is met: · At least one phase of the phase switch is closed, and the corresponding phase electrical quantity is non-zero (e.g., phase A voltage > 50% of the rated value, current > 0.1 times the rated value); · All switches are disconnected, but there is reverse power supply from the charging energy storage line (e.g., the energy storage node supplies power to the line through other paths).

[0111] In the outage state, all phase switches are disconnected and the corresponding phase electrical quantities are all zero, or the switches are closed but the electrical quantities are continuously zero and the power factor is close to 0 (no load but no energy flow).

[0112] Tripping status judgment:

[0113] Protection tripping: protection device action signal is triggered + corresponding phase current drops to zero + switch position changes from closed to open (phase or three-phase tripping).

[0114] Non-protection tripping: The switch position change signal shows disconnection, but there is no protection action record (possibly caused by manual operation or communication error).

[0115] Status information packaging and upload:

[0116] Data formatting: Generate status information packets by line, including:

[0117] Line name / number, substation name, acquisition timestamp;

[0118] Phase switch position (such as A phase closed, B / C phase open), electrical quantity value and status label (normal / abnormal); protection trip type (overcurrent / quick break, etc.), trip phase (single phase / two phase / three phase), whether it is the first trip (distinguishing the status before / after reclosing).

[0119] Abnormal marking and priority: Add red warning tags to detected abnormal conditions (such as protection tripping, switch position and electrical quantity inconsistency) and upload them to the main control station through the priority queue (to ensure that critical fault information is not delayed).

[0120] The present invention uses a collaborative analysis of phase-separated electrical quantities and switch positions to accurately identify asymmetric faults (such as single-phase grounding causing phase A to trip), avoiding the loss of details caused by traditional three-phase unified judgment; distinguishing between "normal shutdown" and "fault disconnection" through power direction and no-load characteristics (power factor) to reduce misjudgments (such as no-load lines being mistakenly reported as faults). Synchronous sampling ensures the temporal consistency of electrical quantities and switch states, avoiding logical contradictions caused by timing deviations (such as first collecting a current mutation and then receiving a switch disconnection signal); the protection signal and the electrical quantity mutation characteristics are linked for verification, reliably distinguishing between real fault tripping and false operation (such as false triggering of a protection device); the substation locally pre-processes abnormal states, reducing the amount of uploaded data while highlighting key information (such as only reporting warning tags + characteristic values), improving the processing efficiency of the master station, and the power direction and energy storage status in the status information provide a basis for subsequent island maintenance strategies (such as giving priority to retaining the line load powered by energy storage).

[0121] In an optional embodiment of the present invention, in step 16, the status information is sent to the master control station, so that the master control station processes the status information based on the status information in combination with the electrical quantities, switch positions, and protection trip signals of the main transformer high-voltage side, medium-voltage side, and tie line collected by the station to obtain a processing result, including:

[0122] In step 161, the master control station receives the preset key line shutdown and tripping status sent by multiple substations, and determines whether the high-voltage side of the main transformer is disconnected from the external system based on the sudden changes in electrical quantities on the high-voltage side, medium-voltage side, and tie lines collected by the master control station:

[0123] Step 162: If the current on the high-voltage side of the main transformer suddenly drops to zero and the corresponding switch position is open, a large islanding determination result is generated;

[0124] Step 163: If the bus voltage on the medium voltage side of the main transformer suddenly drops to zero and the tie line switch is disconnected, a medium islanding determination result is generated;

[0125] Step 164: If the tie-line electrical quantity returns to zero and the protection trip signal is triggered, a tie-line disconnection determination result is generated.

[0126] In this embodiment, the master control station receives the preset key line shutdown and tripping status (such as line phase switch position and protection tripping signal) uploaded by each substation, and simultaneously collects the electrical quantities (voltage, current, power) and switch positions and protection tripping signals of the main transformer high-voltage side and the tie line of the station, and focuses on monitoring the sudden changes of electrical quantities (such as the current / voltage sudden rise / sag amplitude exceeding the threshold);

[0127] Check the status of the high-voltage side of the main transformer:

[0128] If a sudden current drop to zero (close to 0A) is detected and the corresponding switch position is disconnected (physical connection disconnected), it is determined that the high-voltage side of the main transformer is completely disconnected from the external system. Combined with the status of the main grid connection point in the topology analysis results (if the main grid connection point is marked as "off-grid"), a large islanding determination result is generated (the main grid is completely disconnected and the microgrid is completely disconnected from the external grid);

[0129] Determine the islanding condition and check the status of the busbar and tie line on the medium voltage side of the main transformer:

[0130] If the bus voltage on the medium voltage side of the main transformer suddenly drops to zero (indicating a power outage on the medium voltage bus), and the tie line switch is in the disconnected state (the electrical connection between the substations is interrupted);

[0131] Determined to be in island state (the medium voltage bus is disconnected and the microgrid is divided into multiple independent medium voltage areas);

[0132] Tie line disconnection determination and tie line status verification:

[0133] If the electrical quantity (current, power) of the tie line returns to zero and a protection trip signal is detected (such as overcurrent protection), it is determined to be a tie line disconnection event (the tie line is disconnected due to a fault or control instruction, resulting in islanding between substations). Based on the above judgment results, a processing result is generated, including states such as large islanding, medium islanding, and tie line disconnection, and the event type, occurrence time, and related node / line information are marked;

[0134] This example uses differentiated criteria for the main transformer's high-voltage and medium-voltage sides, as well as the tie lines, to distinguish multiple islanding conditions, such as "main grid disconnection," "internal busbar disconnection," and "substation interconnection interruption." This provides a precise basis for hierarchical control (e.g., large islands require global switching to islanding mode, while medium islands require zoned control). By combining electrical quantity mutations with switch states, the fault point can be located within milliseconds (e.g., a main transformer high-voltage side disconnect indicates an external fault, while a tie line disconnection indicates an inter-substation line fault), shortening fault handling time and preventing fault propagation. By integrating substation-reported data with local monitoring data from the master control station, cross-validation is used to avoid single-device false alarms (e.g., if a substation's tie line switch signal misreports, the master control station's monitored electrical quantity returning to zero can be used to assist in the judgment). This improves the reliability of the judgment results. Different islanding conditions correspond to different control logics (e.g., large islands require global energy storage power supply activation, while medium islands require independent power supply maintenance in each zone). The processing results directly drive subsequent load control, energy storage regulation, and other strategies, enhancing the flexibility and effectiveness of the microgrid's emergency response.

[0135] In an optional embodiment of the present invention, in step 17, receiving the processing result through the load control station and collecting the electrical quantities and switch position information of the tie line, the high and low voltage sides of the main transformer, and the energy storage line to obtain the small island state may include:

[0136] Step 171: The load control station receives the tie line decoupling determination result sent by the master control station, and simultaneously collects the tie line current, voltage, and energy storage line power direction of the station;

[0137] Step 172: If the tie line current is zero and the energy storage line power direction is from energy storage to the load side, then determine whether the load side is isolated from the main grid in combination with the local switch position information;

[0138] Step 173: When the load-side electrical quantity is supported only by energy storage and local power supply, it is determined to be a small island state, and the state is fed back to the master control station.

[0139] In this embodiment, the load control station receives the tie line disconnection determination result (i.e., the signal indicating that the tie line is disconnected due to a fault or a control instruction) sent by the master control station;

[0140] Synchronously collect real-time data of this site:

[0141] Tie-line electrical quantities: current, voltage (to determine whether the tie-line is completely de-energized);

[0142] Energy storage line power direction: monitors the power flow direction of the energy storage converter (whether it is "charging" or "discharging");

[0143] Local switch position information: the opening and closing status of the high and low voltage side switches and load side switches of the main transformer.

[0144] Check the status of the tie line after disconnection:

[0145] If the interconnection line current is zero (indicating that no current is flowing and the physical or electrical connection is disconnected), and the energy storage line power direction is transmitted from the energy storage to the load side (i.e. the energy storage is in a "discharge" state, supplying power to the load).

[0146] Load side isolation judgment:

[0147] Combined with the local switch position information, check the electrical connection between the load side and the main grid:

[0148] If the main transformer's high-voltage side switch is disconnected (physically isolated from the external main grid) and the main transformer's medium-voltage or low-voltage side switch is closed (the load side is powered by a local power source), further monitor whether the load-side electrical quantities (such as voltage and frequency) are supported only by the energy storage device and local distributed power sources (such as photovoltaics and small wind turbines) (i.e., no energy input from the main grid or other substations);

[0149] Small island status determination conditions:

[0150] If the interconnection line is disconnected (current is zero), the energy storage is in a discharging state (power flows to the load side), and the load side is completely isolated from the main grid and other substations (relying only on the local power supply), it is determined to be a small island state, and the state information is fed back to the master control station, while marking the involved load area, energy storage node and power supply range.

[0151] This embodiment focuses on the load-side terminal network. By analyzing the energy storage power direction and tie-line status, it can accurately identify "independent load areas powered solely by energy storage and local power sources," avoiding misidentification of intermediate busbar faults as small islands. Determining small islands based on the energy storage line power direction (discharge state) directly triggers the energy storage system's islanding mode switch (e.g., from grid-connected control to droop control), maintaining load-side voltage and frequency stability and improving power supply continuity. After determining the boundaries of the small island, the load control station can dynamically cut off non-critical loads (e.g., interruptible industrial loads) based on local criteria, while retaining critical loads (e.g., residential electricity). The closed-loop mechanism of local data collection and determination reduces reliance on the master control station. Small island status can be quickly confirmed and fed back locally, shortening multi-level communication delays. This approach is particularly suitable for island autonomy in communication interruption scenarios. The determination logic is compatible with multiple distributed power sources (e.g., energy storage and photovoltaics), and the criteria can be flexibly adjusted based on the actual power configuration (e.g., adding photovoltaic output monitoring), improving the method's versatility and adaptability to various microgrid types.

[0152] In an optional embodiment of the present invention, in step 18, generating a result including a large island, a medium island, and a total island status based on the small island status by the master control station may include:

[0153] Step 181: Receive the small islanding status feedback from the load control station through the master control station. If the large islanding determination result is valid, the overall islanding status is marked as a large islanding;

[0154] Step 182: If the medium island determination result is valid and the large island mark is invalid, the overall island state is marked as medium island;

[0155] In step 183, if only a small islanding state exists and the local judgment criteria of the master control station confirm that the load side is operating independently, the total islanding state is marked as a small islanding state, and finally a three-level hierarchical judgment result of a large islanding state, a medium islanding state, and a total islanding state is output.

[0156] In this embodiment, the master control station first receives and verifies the validity of the judgment results of large islands, medium islands, and small islands (such as whether the signal has timed out and whether the data is complete); the priority logic is: large islands > medium islands > small islands (that is, higher-level island states override lower-level ones);

[0157] Big Island Mark:

[0158] If the result of the major islanding determination is valid (the high-voltage side of the main transformer is disconnected from the external system, and the microgrid is completely off-grid), the total islanding state is directly marked as major islanding, and the determination results of medium islanding and small islanding are ignored;

[0159] Middle island mark:

[0160] If the major islanding determination result is invalid (the main grid connection is normal) and the medium islanding determination result is valid (the medium voltage busbar is disconnected and the interconnection between substations is interrupted), the overall islanding status is marked as medium islanding;

[0161] Small island marker:

[0162] If both the large islanding and medium islanding determination results are invalid, and the load control station reports that the small islanding state is valid, and the master control station confirms through local monitoring that the load-side electrical quantity is supported only by the local power source (such as energy storage) (without energy input from the main grid or other substations), then the overall islanding state is marked as small islanding;

[0163] Through the above logic, a judgment result containing the following contents is generated: large island status: marked "yes / no", corresponding to the scenario of complete disconnection of the main grid; medium island status: marked "yes / no", corresponding to the scenario of disconnection of the medium-voltage busbar within the microgrid and isolation between substations; based on the priority, it is finally determined to be a large island, medium island or small island, and the involved area range (such as the main grid connection point, medium-voltage busbar number, load side area) is marked.

[0164] This embodiment clarifies the island level through a priority mechanism, so that the master control station can quickly match the control strategy according to the overall island status (for example, large islands require global activation of energy storage power supply, medium islands require zoned adjustment of interconnection lines, and small islands only require local load control), avoiding control failures caused by policy confusion; three-level hierarchical determination can refine the island boundary (for example, distinguishing "the entire microgrid is off-grid", "internal area isolation", and "terminal load independence"), helping operation and maintenance personnel to quickly locate the fault level (main grid side, bus side, or load side), shortening the troubleshooting time; supporting mixed island scenarios (such as large island state with simultaneous The system ensures the uniqueness of the overall state through priority coverage, adapting to the evolution of islanding under the complex topology of the microgrid (such as multiple main transformers and multiple interconnection lines); low-level islanding states (such as small islands) do not need to trigger global control instructions, and adjustments can be completed only through the local load control station, reducing the computing pressure and communication bandwidth usage of the master station and improving the overall operation efficiency of the system; the three-level hierarchical results can intuitively display the islanding state of each level of the microgrid, which is convenient for real-time presentation through the monitoring interface (such as large islands marked in red, medium islands marked in yellow, and small islands marked in blue), assisting operators to make quick decisions.

[0165] like Figure 2 As shown, an embodiment of the present invention further provides a microgrid system source detection system 20, comprising:

[0166] The acquisition module 21 is used to collect electrical quantities and switch position information of each interval of multiple substations in the microgrid system, perform global topology analysis based on the electrical quantities and switch position information, and obtain topology analysis results;

[0167] An identification module 22 is configured to identify the grid connection or disconnection status of the microgrid system and the external grid based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities;

[0168] The sending module 23 is used to trigger the unplanned off-grid control strategy and send line status collection instructions to multiple substations when it is identified that the microgrid is unplanned off-grid based on the on-grid or off-grid status;

[0169] The processing module 24 is used to respond to the line status collection instruction through multiple substations, collect the electrical quantities, phase switch positions and protection tripping signals of the preset key lines respectively, determine the line shutdown and tripping status, and obtain status information; send the said status information to the main control station, so that the main control station processes the said status information based on the combination of the electrical quantities, switch positions and protection tripping signals of the high-voltage side, medium-voltage side and tie line of the main transformer collected by the station to obtain the processing results; receive the processing results through the load control station, and collect the electrical quantities and switch position information of the tie line, the high-voltage and low-voltage sides of the main transformer and the energy storage line to obtain the small island status; generate the results including large island, medium island and total island status based on the small island status through the main control station.

[0170] Optionally, performing a global topology analysis based on the electrical quantity and the switch position information to obtain a topology analysis result includes:

[0171] Based on the electrical quantities collected by each substation, the voltage and current correlation between each node in the microgrid system is determined. Combined with the closed / open status of the phase switches in the switch position information, a dynamic topology connection matrix is ​​constructed.

[0172] Analyzing electrical connectivity paths using a graph theory algorithm based on the dynamic topology connection matrix; when the electrical quantity of a branch returns to zero and the corresponding switch position is disconnected, the current branch is determined to be removed from the global topology;

[0173] The branch removal status of each substation is integrated to generate a topology analysis result that reflects the current electrical connection relationship of the microgrid system.

[0174] Optionally, performing a global topology analysis based on the electrical quantity and the switch position information to obtain a topology analysis result includes:

[0175] Based on the electrical quantities collected by each substation, the voltage and current correlation between each node in the microgrid system is determined. Combined with the closed / open status of the phase switches in the switch position information, a dynamic topology connection matrix is ​​constructed.

[0176] Analyzing the electrical connectivity path according to the dynamic topology connection matrix, and determining that the current branch is removed from the global topology when the electrical quantity of the branch returns to zero and the corresponding switch position is in an open state;

[0177] The branch removal status of each substation is integrated to generate a topology analysis result that reflects the current electrical connection relationship of the microgrid system.

[0178] Optionally, based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities, identifying the grid-connected or off-grid status of the microgrid system and the external grid includes:

[0179] Based on the main network connection point status in the topology analysis result, if the electrical quantity at the main network connection point is continuously non-zero and the switch position is closed, it is determined to be in a grid-connected state;

[0180] When it is detected that the electrical quantity at the main grid connection point suddenly drops to zero, and the protection device action signal is triggered or the switch change signal indicates disconnection, combined with the sudden change characteristics of the fault electrical quantity, it is determined to be an off-grid state;

[0181] When an off-grid state occurs without receiving a planned off-grid instruction, it is marked as an unplanned off-grid event.

[0182] Optionally, multiple substations respond to line status collection instructions, respectively collecting electrical quantities, phase switch positions, and protection trip signals of preset key lines, determining the line's shutdown and tripping status, and obtaining status information, including:

[0183] Each substation analyzes the line status acquisition instruction issued by the master control station, determines the target line and the parameters to be collected, calls the local measurement and control device to perform synchronous sampling on the designated line, and collects the phase-by-phase electrical quantities of the preset key line;

[0184] Collect phase switch positions and protection trip signals, perform switch status logic judgment, and obtain switch / protection signal verification results;

[0185] Based on the electrical quantity acquisition results and the switch / protection signal verification results, the line status is judged to obtain the line status judgment result;

[0186] Based on the line status judgment results, status information including line name, timestamp, phase switch position, electrical quantity status label and trip type is generated.

[0187] Optionally, the status information is sent to a master control station, so that the master control station processes the status information based on the information and in combination with the electrical quantities, switch positions, and protection trip signals of the main transformer high-voltage side, medium-voltage side, and tie lines collected by the station to obtain a processing result, including:

[0188] The master control station receives the preset key line shutdown and tripping status sent by multiple substations. Combined with the sudden changes in electrical quantities on the high-voltage side, medium-voltage side, and tie lines collected by the master control station, it determines whether the high-voltage side of the main transformer is disconnected from the external system:

[0189] If the current on the high-voltage side of the main transformer suddenly drops to zero and the corresponding switch position is disconnected, a large islanding determination result is generated;

[0190] If the bus voltage on the medium voltage side of the main transformer suddenly drops to zero and the tie line switch is disconnected, the islanding determination result is generated;

[0191] If the electrical quantity of the tie line returns to zero and the protection trip signal is triggered, the tie line disconnection judgment result is generated.

[0192] Optionally, the load control station receives the processing results and collects electrical quantities and switch position information on the tie line, high and low voltage sides of the main transformer, and energy storage line to obtain the small island status, including:

[0193] The load control station receives the tie line decoupling judgment result sent by the master control station, and simultaneously collects the tie line current, voltage and energy storage line power direction of the station;

[0194] If the tie line current is zero and the energy storage line power is transmitted from the energy storage to the load side, then the local switch position information is combined to determine whether the load side is isolated from the main grid;

[0195] When the load-side electrical quantity is supported only by energy storage and local power supply, it is determined to be a small island state and the state is fed back to the master control station.

[0196] Optionally, the master station generates results based on the small island status, including large island, medium island, and total island status, including:

[0197] The master control station receives the small islanding status feedback from the load control station. If the large islanding determination result is valid, the overall islanding status is marked as large islanding.

[0198] If the medium island determination result is valid and the large island mark is invalid, the overall island status is marked as medium island;

[0199] If only a small islanding state exists and the local judgment criteria of the master control station confirm that the load side is operating independently, the total islanding state is marked as a small islanding state, and the final output is a three-level hierarchical judgment result of large islanding, medium islanding and total islanding state.

[0200] It should be noted that this system is a system corresponding to the above method, and all implementation methods in the above method embodiment are applicable to this embodiment and can achieve the same technical effects.

[0201] An embodiment of the present invention further provides a computing device comprising: a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction implements the steps of the above-described method when executed by the processor.

[0202] An embodiment of the present invention further provides a computer-readable storage medium comprising instructions, which, when executed on a computer, cause the computer to execute the method described above. All implementations in the above method embodiments are applicable to this embodiment and can achieve the same technical effects.

[0203] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0204] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0205] In the embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0206] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0207] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0208] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, ROM, RAM, a magnetic disk, or an optical disk.

[0209] In addition, it should be noted that, in the apparatus and method of the present invention, it is obvious that each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. Moreover, the steps of performing the above-mentioned series of processing can naturally be performed in chronological order according to the order of description, but it is not necessary to perform them in chronological order, and some steps can be performed in parallel or independently of each other. For those of ordinary skill in the art, it will be understood that all or any steps or components of the method and apparatus of the present invention can be implemented in any computing device (including processors, storage media, etc.) or a network of computing devices in hardware, firmware, software or a combination thereof, which can be achieved by those of ordinary skill in the art using their basic programming skills after reading the description of the present invention.

[0210] Therefore, the purpose of the present invention can also be achieved by running a program or a group of programs on any computing device. The computing device can be a well-known general-purpose device. Therefore, the purpose of the present invention can also be achieved simply by providing a program product containing program code that implements the method or device. That is to say, such a program product also constitutes the present invention, and the storage medium storing such a program product also constitutes the present invention. Obviously, the storage medium can be any well-known storage medium or any storage medium developed in the future. It should also be pointed out that in the device and method of the present invention, it is obvious that each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. In addition, the steps of performing the above-mentioned series of processing can naturally be performed in chronological order according to the order of description, but do not necessarily need to be performed in chronological order. Certain steps can be performed in parallel or independently of each other.

[0211] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for detecting a source of a microgrid system, applied to a source-grid-load-storage microgrid system, characterized in that: The method comprises: Collect electrical quantities and switch position information of each bay of multiple substations in the microgrid system; Performing a global topology analysis based on the electrical quantity and switch position information to obtain a topology analysis result; Based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals and the fault electrical quantities, the grid connection or disconnection status of the microgrid system and the external grid is identified; Based on the grid-connected or off-grid status, when an unplanned off-grid event is detected in the microgrid, the unplanned off-grid control strategy is triggered and line status collection instructions are sent to multiple substations; Multiple substations respond to line status collection instructions, respectively collecting electrical quantities, phase switch positions, and protection trip signals of preset key lines, determining line shutdown and tripping status, and obtaining status information; The status information is sent to the master control station, so that the master control station processes the status information based on the electrical quantities of the high-voltage side, medium-voltage side and tie line of the main transformer, the switch position and the protection trip signal collected by the master control station to obtain a processing result; The load control station receives the processing results and collects the electrical quantities and switch position information of the tie line, the high and low voltage sides of the main transformer, and the energy storage line to obtain the small island status; Based on the small island status, the master control station generates results including large island status, medium island status and total island status.

2. The method for detecting a microgrid system source according to claim 1, characterized in that: Performing a global topology analysis based on the electrical quantity and switch position information to obtain a topology analysis result, including: Based on the electrical quantities collected by each substation, the voltage and current correlation between each node in the microgrid system is determined. Combined with the closed / open status of the phase switches in the switch position information, a dynamic topology connection matrix is ​​constructed. Analyzing the electrical connectivity path according to the dynamic topology connection matrix, and determining that the current branch is removed from the global topology when the electrical quantity of the branch returns to zero and the corresponding switch position is in an open state; The branch removal status of each substation is integrated to generate a topology analysis result that reflects the current electrical connection relationship of the microgrid system.

3. The method for detecting a microgrid system source according to claim 1, wherein: Based on the topology analysis results, combined with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities, the grid-connected or off-grid status of the microgrid system and the external grid is identified, including: Based on the main network connection point status in the topology analysis result, if the electrical quantity at the main network connection point is continuously non-zero and the switch position is closed, it is determined to be in a grid-connected state; When it is detected that the electrical quantity at the main grid connection point suddenly drops to zero, and the protection device action signal is triggered or the switch change signal indicates disconnection, combined with the sudden change characteristics of the fault electrical quantity, it is determined to be an off-grid state; When an off-grid state occurs without receiving a planned off-grid instruction, it is marked as an unplanned off-grid event.

4. The method for detecting a microgrid system source according to claim 1, wherein: Multiple substations respond to line status collection instructions, respectively collecting electrical quantities, phase switch positions, and protection trip signals of preset key lines, identifying line shutdown and tripping status, and obtaining status information, including: Each substation analyzes the line status acquisition instruction issued by the master control station, determines the target line and the parameters to be collected, calls the local measurement and control device to perform synchronous sampling on the designated line, and collects the phase-by-phase electrical quantities of the preset key line; Collect phase switch positions and protection trip signals, perform switch status logic judgment, and obtain switch / protection signal verification results; Based on the electrical quantity acquisition results and the switch / protection signal verification results, the line status is judged to obtain the line status judgment result; Based on the line status judgment results, status information including line name, timestamp, phase switch position, electrical quantity status label and trip type is generated.

5. The method for detecting a source of a microgrid system according to claim 1, wherein: The status information is sent to the master control station, and the master control station processes the status information based on the information and the electrical quantities, switch positions, and protection trip signals of the main transformer high-voltage side, medium-voltage side, and tie lines collected by the station to obtain processing results, including: The master control station receives the preset key line shutdown and tripping status sent by multiple substations. Combined with the sudden changes in electrical quantities on the high-voltage side, medium-voltage side, and tie lines collected by the master control station, it determines whether the high-voltage side of the main transformer is disconnected from the external system: If the current on the high-voltage side of the main transformer suddenly drops to zero and the corresponding switch position is disconnected, a large islanding determination result is generated; If the bus voltage on the medium voltage side of the main transformer suddenly drops to zero and the tie line switch is disconnected, the islanding determination result is generated; If the electrical quantity of the tie line returns to zero and the protection trip signal is triggered, the tie line disconnection judgment result is generated.

6. The method for detecting a microgrid system source according to claim 1, wherein: The load control station receives the processing results and collects the electrical quantities and switch position information of the tie line, the high and low voltage sides of the main transformer, and the energy storage line to obtain the small island status, including: The load control station receives the tie line decoupling judgment result sent by the master control station, and simultaneously collects the tie line current, voltage and energy storage line power direction of the station; If the tie line current is zero and the energy storage line power is transmitted from the energy storage to the load side, then the local switch position information is combined to determine whether the load side is isolated from the main grid; When the load-side electrical quantity is supported only by energy storage and local power supply, it is determined to be a small island state and the state is fed back to the master control station.

7. The method for detecting a microgrid system source according to claim 1, wherein: Based on the small island status, the master station generates results including large island, medium island and total island status, including: The master control station receives the small islanding status feedback from the load control station. If the large islanding determination result is valid, the overall islanding status is marked as large islanding. If the medium island determination result is valid and the large island mark is invalid, the overall island status is marked as medium island; If only a small islanding state exists and the local judgment criteria of the master control station confirm that the load side is operating independently, the total islanding state is marked as a small islanding state, and the final output is a three-level hierarchical judgment result of large islanding, medium islanding and total islanding state.

8. A detection system for a microgrid system source, characterized in that: include: An acquisition module is used to collect electrical quantities and switch position information of each interval of multiple substations in the microgrid system, perform global topology analysis based on the electrical quantities and switch position information, and obtain a topology analysis result; an identification module for identifying the grid-connected or off-grid status of the microgrid system and the external grid based on the topology analysis results and in combination with the action signals of the protection devices in each substation, the switch position change signals, and the fault electrical quantities; The sending module is used to trigger the unplanned off-grid control strategy and send line status collection instructions to multiple substations based on the grid-connected or off-grid status when an unplanned off-grid event is detected in the microgrid; The processing module is used to respond to line status collection instructions through multiple substations, respectively collect electrical quantities, phase switch positions and protection trip signals of preset key lines, determine the line's shutdown and tripping status, and obtain status information; The status information is sent to the master control station, so that the master control station processes the status information based on the electrical quantities of the high-voltage side, medium-voltage side and tie line of the main transformer, the switch position and the protection trip signal collected by the master control station to obtain a processing result; The load control station receives the processing results and collects the electrical quantities and switch position information of the tie line, the high and low voltage sides of the main transformer, and the energy storage line to obtain the small island status; Based on the small island status, the master control station generates results including large island status, medium island status and total island status.

9. A computing device, characterized in that include: A processor and a memory storing a computer program, wherein when the computer program is executed by the processor, the method according to any one of claims 1 to 7 is performed.

10. A computer-readable storage medium, characterized in that The device stores instructions, which, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 7.

Images