A method, system, and device for detecting sources in a microgrid system.

Abstract

This invention provides a method, system, and device for detecting sources in a microgrid system, relating to the field of power grid technology. The method includes: multiple substations responding to line status acquisition commands to collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determining line on / off and trip states, and sending the status information to the main control station. The main control station processes the status information, combined with the electrical quantities, switch positions, and protection trip signals collected by the substation from the high-voltage side, medium-voltage side, and tie lines of the main transformer, to obtain a processing result. The load control station receives the processing result and collects the electrical quantities and switch position information of the tie lines, the high- and low-voltage sides of the main transformer, and the energy storage lines to obtain a small islanding state. Based on the small islanding state, the main control station generates a result including a large islanding, a medium islanding, and a total islanding state. The solution of this invention can improve the self-healing capability and operational stability of microgrids in off-grid scenarios.

Description

Technical Field

[0001] This invention relates to the field of power grid technology, and in particular to a method, system and equipment for detecting sources in a microgrid system. Background Technology

[0002] Traditional islanding detection methods mainly rely on monitoring local electrical quantities (such as voltage / frequency deviations and harmonic variations) or interruptions in communication signals. For example, passive detection detects grid disconnection by monitoring sudden changes in voltage amplitude and frequency, but it is easily affected by load fluctuations and changes in distributed power output, resulting in a high false alarm rate. Active detection observes the response by injecting disturbance signals, which may affect 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 state judgment of a single node and lack real-time analysis of the global topology of the microgrid. This makes it impossible to accurately distinguish between multiple levels of states such as large islanding (complete disconnection of the main grid), medium islanding (partial disconnection of medium-voltage buses), and small islanding (independent operation of the load side) in complex network structures, thus affecting the accuracy of control strategies. Summary of the Invention

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

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] This invention provides a method for detecting sources in 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] A global topology analysis is performed based on the electrical quantities and switch position information to obtain the topology analysis results;

[0008] Based on the topology analysis results, and combined with the action signals of the protection devices in each substation, switch change signals, and fault electrical quantities, the grid-connected or off-grid status of the microgrid system with the external power 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 acquisition commands are sent to multiple substations.

[0010] By responding to line status acquisition commands through multiple substations, the electrical quantities, phase switch positions and protection trip signals of preset key lines are collected respectively, and the line on / off and trip status is determined to obtain status information.

[0011] The status information is sent to the main control station, which then processes the status information in conjunction with the electrical quantities, switch positions, and protection trip signals collected by the station from the high-voltage side, medium-voltage side, and tie lines of the main transformer to obtain the processing result.

[0012] The load control station receives and processes the results, and collects electrical quantities and switch position information of tie lines, high and low voltage sides of main transformers and energy storage lines to obtain the islanding status.

[0013] The main control station generates results based on the small island status, including the large island, medium island, and total island status.

[0014] Optionally, a global topology analysis is performed based on the electrical quantities and switch position information to obtain the topology analysis results, including:

[0015] Based on the electrical quantities collected by each substation, the voltage and current correlation between nodes in the microgrid system is determined, and a dynamic topology connection matrix is ​​constructed by combining the phase switch closing / opening status in the switch position information.

[0016] Based on the dynamic topology connection matrix, the electrical connection path is analyzed. When the electrical quantity of the branch is zero and the corresponding switch position is in the open state, it is determined that the current branch is removed from the global topology.

[0017] By integrating the branch removal status of each substation, a topology analysis result reflecting the current electrical connection relationship of the microgrid system is generated.

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

[0019] Based on the topology analysis results, the status of the main network connection point is as follows: 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 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 that it is disconnected, the state is determined to be off-grid based on the sudden change characteristics of the fault electrical quantity.

[0021] If no planned disconnection instruction is received when disconnection occurs, it is marked as an unplanned disconnection event.

[0022] Optionally, multiple substations respond to line status acquisition commands to collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determine line activation / deactivation and tripping status, and obtain status information, including:

[0023] Each substation analyzes the line status acquisition instructions issued by the main control station, determines the target line and the parameters to be acquired, calls the local measurement and control device to synchronously sample the designated line, and collects the phase electrical quantities of the preset key line.

[0024] Collect the position of the phase switch and the protection trip signal, perform logic judgment on the switch status, and obtain the verification results of the switch / protection signal;

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

[0026] Based on the line status determination 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 the main control station, which then processes the status information in conjunction with the electrical quantities, switch positions, and protection trip signals collected by the station from the high-voltage side, medium-voltage side, and tie lines of the main transformer to obtain the processing result, including:

[0028] By receiving preset critical line activation / deactivation and tripping statuses from multiple substations via the main control station, and combining this with the electrical quantity fluctuations collected by the main control station on the high-voltage side, medium-voltage side, and tie lines of the main transformer, it is determined 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 is in the open position, a large islanding determination result is generated.

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

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

[0032] Optionally, the processing results are received through the load control station, and electrical quantities and switch position information of tie lines, high and low voltage sides of the main transformer, and energy storage lines are collected to obtain the islanding status, including:

[0033] The load control station receives the tie-line disconnection judgment result sent by the main 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 power direction of the energy storage line is from the energy storage to the load side, then the local switch position information is used to determine whether the load side is isolated from the main grid.

[0035] When the electrical quantities on the load side are supported only by energy storage and local power supply, it is determined to be in a small island state, and this state is fed back to the main control station.

[0036] Optionally, the main control station can generate results based on the small island status, including the large island, medium island, and overall island status, including:

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

[0038] If the result of the medium island determination is valid and the large island label is invalid, then the overall island status is labeled as medium island.

[0039] If only a small islanding state exists and the local criteria of the master station confirm that the load side is operating independently, then 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] Embodiments of the present invention also propose a detection system for sources in a microgrid system, comprising:

[0041] The acquisition module is used to acquire electrical quantities and switch position information of each bay of multiple substations in the microgrid system, and to perform global topology analysis based on the electrical quantities and switch position information to obtain the topology analysis results.

[0042] The identification module is used to identify the grid-connected or off-grid status of the microgrid system with respect to the topology analysis results, combined with the action signals of the protection devices in each substation, the switch 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 acquisition commands to multiple substations when an unplanned off-grid event is detected, based on the grid-connected or off-grid status.

[0044] The processing module is used to respond to line status acquisition commands through multiple substations, collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determine line operation and tripping status, and obtain status information; send the status information to the main control station, which processes the status information based on the electrical quantities, switch positions, and protection trip signals of the high-voltage side, medium-voltage side, and tie lines of the main transformer collected by the substation, and obtains the processing result; receive the processing result through the load control station, and collect electrical quantities and switch position information of the tie lines, high and low voltage sides of the main transformer, and energy storage lines to obtain the small island status; and generate a result including the large island, medium island, and overall island status based on the small island status through the main control station.

[0045] Embodiments of the present invention also provide a computing device, including: a processor and a memory storing a computer program, wherein the computer program, when run by the processor, executes the method described above.

[0046] Embodiments of the present invention also provide a computer-readable storage medium comprising: storage instructions that, when executed on a computer, cause the computer to perform the method described above.

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

[0048] The microgrid system source detection method of this invention collects electrical quantities and switch position information of each bay 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 protection devices in each substation, switch change signals, and fault electrical quantities, identifies the grid-connected or off-grid status of the microgrid system with the external power grid; based on the grid-connected or off-grid status, when an unplanned off-grid event is detected, an unplanned off-grid control strategy is triggered, and line status acquisition commands are sent to multiple substations; the method involves multiple substations responding to the line status acquisition commands. The system collects electrical quantities, phase switch positions, and protection trip signals from preset key lines to determine line activation / deactivation and tripping status, obtaining status information. This status information is then sent to the main control station, which processes it based on the status information, combined with electrical quantities, switch positions, and protection trip signals collected from the high-voltage and medium-voltage sides of the main transformer and tie lines, to obtain a processing result. The load control station receives the processing result and collects electrical quantities and switch position information from tie lines, the 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 main control station generates a result including large islanding, medium islanding, and overall islanding status. This can improve the self-healing capability and operational stability of the microgrid in off-grid scenarios. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the detection method for microgrid system sources according to the present invention;

[0050] Figure 2 This is a schematic diagram of the module of the microgrid system source detection system of the present invention. Detailed Implementation

[0051] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

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

[0053] Step 11: Collect electrical quantities and switch position information for each bay of multiple substations in the microgrid system;

[0054] Step 12: Perform global topology analysis based on the electrical quantities and switch position information to obtain the topology analysis results;

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

[0056] Step 14: 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 acquisition instructions are sent to multiple substations.

[0057] Step 15: Through multiple substations responding to the line status acquisition command, the electrical quantities, phase switch positions and protection trip signals of the preset key lines are collected respectively to determine the line on / off and trip status and obtain status information.

[0058] Step 16: Send the status information to the main control station, so that the main control station can process the status information in combination with the electrical quantities, switch positions and protection trip signals of the high voltage side, medium voltage side and tie line of the main transformer collected by the station to obtain the processing result;

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

[0060] Step 18: The main control station generates a result that includes the status of large islands, medium islands, and total islands based on the status of small islands.

[0061] In this embodiment, by collecting electrical quantities and switch position information from each substation in real time, a dynamic topology connection matrix is ​​constructed. Combined with graph theory algorithms, the global topology structure is quickly updated, significantly improving the adaptability to changes in microgrid operation modes and avoiding misjudgment problems caused by traditional fixed topology models. Based on the collaborative data interaction between the master control station and substations, and by integrating the action signals of protection devices, switch position signals, and sudden changes in fault electrical quantities, it can quickly distinguish between multiple levels of states such as large islanding (complete disconnection of the main grid), medium islanding (disconnection of the medium-voltage bus), and small islanding (independent operation on the load side), providing a reliable basis for hierarchical control. By triggering unplanned off-grid control strategies, multiple substations are linked to collect critical line status information. Combined with the real-time monitoring of the high-voltage side, medium-voltage side, and tie lines of the main transformer by the master control station, fault location and islanding determination are completed within milliseconds, significantly shortening the control response time. The load control station dynamically cuts off non-critical load switches based on instructions from the master control station and local criteria, avoiding over- 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, improving 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 transmits off-grid information using the GOOSE protocol, reducing the amount of communication data while ensuring real-time performance, and reducing the risk of control failure due to communication delays or interruptions.

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

[0063] Step 121: Based on the electrical quantities collected by each substation, determine the voltage and current correlation between nodes in the microgrid system, and construct a dynamic topology connection matrix by combining the phase switch closing / opening status in the switch position information.

[0064] Step 122: Based on the dynamic topology connection matrix, analyze the electrical connection path using graph theory algorithm. When the electrical quantity of a branch is zero and the corresponding switch position is in the open state, it is determined that the current branch is removed from the global topology.

[0065] Step 123: Integrate the branch removal status of each substation to generate topology analysis results that reflect the current electrical connection relationship of the microgrid system; the topology analysis results include the real-time topology structure of the main grid connection point, tie lines and energy storage nodes.

[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 nodes (e.g., if the voltage difference between adjacent nodes is less than a threshold and the current flow direction conforms to Kirchhoff's laws, it is considered an association). The phase status (A / B / C phase closed / open) in the switch position information is converted into matrix elements: closed phase is recorded as "1", and open phase is recorded as "0". For example, if a switch has phase A closed and phases B / C open, then the A phase element of that branch in the corresponding matrix is ​​1, and the B / C phase is 0. Using nodes as rows / columns, based on electrical association and switch phase status, an N×N dynamic matrix (N is the number of nodes) is generated. The element values ​​reflect the phase connectivity between corresponding nodes (e.g., matrix element M[i,j]=[1,0,1] indicates that phases A and C are connected between nodes ij, and phase B is open). This invention reflects in real-time switch phase-by-phase operations (such as single-phase tripping after a single-phase ground fault) and changes in electrical quantities. Phase-by-phase states are incorporated into topology analysis, accurately identifying local topology changes after asymmetrical faults (such as two-phase short circuits). The dynamic matrix is ​​traversed; if all three-phase electrical quantities of a branch (i,j) are zero (e.g., current and power are zero), and the corresponding switch phase-by-phase states are all open (all matrix elements are 0), then the branch is marked as "to be removed." Exception handling: if the electrical quantities are zero but the switch is closed (e.g., an unloaded line), the branch is retained (considered as unloaded connectivity). A connectivity analysis algorithm from graph theory (such as Breadth-First Search (BFS) or Depth-First Search (DFS)) is used. Starting from the main network connection point, the "1" elements in the matrix are traversed to identify valid electrical paths. For example, if the main network connection point is node S, and BFS reveals that node S cannot reach node T through any "1" element path, then the branch containing node T is determined to be disconnected from the main network. For branches marked as "to be removed," if they are not in any valid electrical path, then... Remove from the topology; if other phases are still connected (e.g., phase A is closed, phases B / C are open but the electrical quantity of phase A is non-zero), then retain that phase branch. In this embodiment, the no-load state of "switch open but electrical quantity non-zero" is distinguished from the true disconnection state of "switch open and electrical quantity zero" to avoid misjudgment (e.g., no-load line is mistakenly judged as fault removal). The connected paths are updated in real time through graph theory algorithms to adapt to the dynamic changes in the topology caused by the switching of distributed power sources (e.g., energy storage node access / exit) in the microgrid; collect the tags of each substation. The "Branch to be Removed" list removes branches that are still globally connected due to local faults (such as internal switch tripping within a substation) but are still connected globally (e.g., those connected via other substations). For example, if substation X reports a branch disconnected, but the main control station finds through data from other substation Y that the branch can still be connected via station Y, then it is not included in the global removal list. The real-time connectivity status of main grid connection points (such as high-voltage side nodes of the main transformer), tie line nodes (nodes connecting different substations), and energy storage nodes (such as energy storage converter access points) is marked.

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

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

[0069] Energy storage node: If it is in a discharging state (current outflow node), it is marked as "power supply state"; if it is in a charging state, it is marked as "load state".

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

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

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

[0073] Step 131: Based on the status of the main network connection point in the topology analysis results, 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 grid-connected state.

[0074] Step 132: When 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, the state is determined to be off-grid based on the sudden change characteristics of the fault electrical quantity.

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

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

[0077] Offline status determination:

[0078] When the electrical quantity at the main grid connection point is detected to suddenly drop to zero (such as voltage or current dropping to 0 or close to 0), a preliminary off-grid warning is triggered; protection device action signals: whether overcurrent, overvoltage or other fault protection signals are triggered (indicating that off-grid may be caused by a fault);

[0079] Switch position change signal: Whether the switch corresponding to the main network connection point has changed from "closed" to "open" (physical connection disconnected);

[0080] Fault electrical quantity change characteristics: such as sudden change in current phase, voltage frequency deviation from the main grid standard value, etc. (to help determine the fault type). If at least one of the above conditions is met (such as protection action and sudden drop in electrical quantity, or switch opening and electrical quantity returning to zero), it is determined to be an off-grid state. After determining the off-grid state, check whether the system has received a planned off-grid command (such as an off-grid command triggered by manual operation or preset program). If no planned command is received, it is marked as an unplanned off-grid event, triggering subsequent control strategies (such as the unplanned off-grid response in step 3).

[0081] This embodiment combines topology status, electrical quantity changes, protection signals, and switch status to avoid misjudgment based on single data (such as relying solely on switch position, which may lead to misjudgment of connection status due to contact failure). Through the linkage analysis of electrical quantity abrupt change characteristics (such as sudden drop, phase abnormality) and protection actions, the cause of disconnection (such as short circuit fault, switch malfunction) can be located in milliseconds, and the nature of disconnection (human planning or fault triggering) can be determined. This provides a precise basis for subsequent control strategies (such as unplanned disconnection requiring emergency activation of islanding control, while planned disconnection can be switched in an orderly manner), reducing misjudgments of status due to communication delays or single sensor failures, and ensuring the stability and safety of the microgrid when switching between grid-connected and off-grid modes.

[0082] In an optional embodiment of the present invention, step 14, based on the grid-connected or off-grid status, when an unplanned off-grid event is detected in the microgrid, triggers an unplanned off-grid control strategy and sends line status acquisition instructions to multiple substations, which may include:

[0083] Step 141: Based on the judgment result of step 13, check again whether the electrical quantities (voltage / current / power) of the main grid connection point are continuously zero, confirm the consistency between the protection device action signal (such as overcurrent protection trigger) and the switch change signal (main grid switch from "closed" to "open"), and at the same time verify whether there is a planned off-grid instruction (such as manual operation record or system preset program trigger log).

[0084] Logical judgment: If all three conditions are met simultaneously, namely "electrical quantity returning to zero + protection action / switch disconnection + unplanned instruction", it is officially marked as an unplanned off-grid event, triggering the subsequent control process.

[0085] Step 142: Based on the topology analysis results generated in Step 12, locate the critical lines directly associated with the main grid connection point (such as the main transformer high-voltage side incoming line and the main tie line) and the corresponding substation nodes (such as the substations connecting to the main grid and the substations at both ends of the tie line); determine the list of lines whose status needs to be collected first (such as the main transformer high-voltage side line, the cross-substation tie line, and the energy storage converter outgoing line) in the order of "main grid connection point → tie line → energy storage access line", and associate them with the corresponding substations (such as substation A being responsible for the main grid incoming line, and substations B and C being responsible for the tie line segments).

[0086] Step 143: Generate customized acquisition instructions for each target substation, including:

[0087] Data collection target: The name / number of the specified critical path (e.g., "L1 Main Network Incoming Line" "L3 Link Line AB Section");

[0088] Collected parameters: phase electrical quantities (A / B / C phase voltage, current, power), phase switch position (closed / open), protection trip signal (whether overcurrent / instantaneous overcurrent protection is triggered);

[0089] Data acquisition timeliness: The substation is required to complete data acquisition and return within a millisecond period (e.g., 10ms).

[0090] Command distribution mechanism: Commands are sent to the target substation via hard contact signals or the GOOSE protocol to ensure real-time communication (reduce the impact of network latency), while multi-path redundant communication (such as fiber optic + wireless) is used to improve the reliability of command transmission.

[0091] Step 144, Local Data Acquisition: After receiving the instruction, the substation immediately starts the dedicated acquisition module to synchronously sample the electrical quantities of the specified line (ensuring that the data timestamps of each phase are consistent), and reads the switch position register and protection device action records.

[0092] Preliminary status assessment: The substation preprocesses the data locally, marks abnormal statuses (such as a sudden change in phase current to 3 times the rated value, or a contradiction between switch position and electrical quantity), and compresses and packages the original data and assessment results, ready to be uploaded to the main control station.

[0093] This invention achieves instant response to unplanned off-grid events through millisecond-level command triggering and data acquisition, shortening fault location time (traditional methods require second-level polling, which is improved to millisecond-level here); it targets the collection of critical line status, avoiding data flooding across the entire network, focusing on suspected fault areas, and improving location accuracy (such as directly locking the main network incoming line or tie line break); it utilizes multi-substation distributed acquisition to achieve cross-verification of data for the same line (such as substation A collecting data from the main network side and substation B collecting data from the load side, comparing and judging line continuity), avoiding misjudgments caused by single-site sensor failures; phase-by-phase data acquisition supports asymmetrical fault analysis (such as the status identification of single-phase tripping after single-phase grounding), improving the refinement of topology analysis.

[0094] In an optional embodiment of the present invention, step 15 involves multiple substations responding to line status acquisition commands to collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determine line activation / deactivation and tripping status, and obtain status information. This process may include:

[0095] Step 151: Each substation analyzes the line status acquisition instructions issued by the main control station to determine the target line and the parameters to be acquired. The local measurement and control device is called to synchronously sample the designated line and collect the phase electrical quantities of the preset key line. Specifically, each substation analyzes the line status acquisition instructions issued by the main control station to determine the target line and the parameters to be acquired. The local measurement and control device is called to synchronously sample the designated line and collect the phase electrical quantities of the preset key line, including voltage, current, frequency and power direction of the energy storage line. The abnormal state of the line is judged based on the comparison results of the electrical quantities and the rated values.

[0096] Step 152: Collect the phase switch position and protection trip signal, perform switch status 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 status 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] For scenarios where the switch is closed but the electrical quantity is zero, determine whether it is a normal no-load state by combining the power factor.

[0099] Based on the action records of the protection device and the characteristics of sudden changes in electrical quantities, the fault correlation of the protection trip signal is verified;

[0100] Step 153: Based on the electrical quantity acquisition results and the switch / protection signal verification results, perform line status determination to obtain the line status determination result. Specifically, based on the electrical quantity acquisition results of step 151 and the switch / protection signal verification results of step 152, perform line status determination:

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

[0102] When all phase switches are open and the electrical quantity is zero, or when the switch is closed but the electrical quantity remains zero and the power factor meets the no-load characteristics, it is determined to be in a shutdown 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 change display shows open but there is no protection action record, it is determined to be a non-protection trip.

[0104] Step 154: Based on the line status judgment result, generate status information including line name, timestamp, phase switch position, electrical quantity status label and trip type. 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 warning labels to abnormal status and upload them to the main control station through a priority queue.

[0105] In this embodiment, after receiving the line status acquisition command sent by the main control station through the substation, it parses the target line list (such as "L1 main grid incoming line" and "L5 energy storage outgoing line") and parameter requirements (phase electrical quantities, switch positions, protection signals), and calls the local measurement and control device to perform synchronous sampling on the designated line (the sampling time difference between each phase is <1ms). It collects parameters such as phase voltage (such as the effective value and phase of phase A voltage), current (instantaneous value, power direction), and frequency, and compares them with rated values ​​to determine if there are any abnormalities (such as voltage drop >30% of rated value, current surge >2 times rated value). For energy storage lines, it additionally monitors the power direction (current inflow / outflow nodes) to determine whether the energy storage is in a charging or discharging state.

[0106] Switch status 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 (if the instruction requires the switch to be in the closed state when collecting data, if a phase is actually open, mark it as abnormal); for the scenario of "switch closed but electrical quantity is zero" (such as no-load line), determine whether it is a normal no-load state by the power factor (close to 0) to avoid misjudging it as a fault disconnection.

[0108] Verify the protection trip signal by checking the protection device's operation record (such as whether overcurrent stage I or instantaneous overcurrent protection is triggered), and combine this with the characteristics of sudden changes in electrical quantities (such as a 180° change in current phase) to confirm whether the trip was caused by a fault (rather than a malfunction).

[0109] Determining if a stock is suspended from trading:

[0110] The operation status meets any of the following conditions: • At least one phase of the phase switch is closed, and the electrical quantity of the corresponding phase is not zero (e.g., phase A voltage > 50% of the rated value, current > 0.1 times the rated value); • All switches are open but there is a charging state of the energy storage line supplying power in reverse (e.g., the energy storage node supplies power to the line through other paths).

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

[0112] Trip status determination:

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

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

[0115] Status information encapsulation and uploading:

[0116] Data formatting: Generate status information packets according to the line, including:

[0117] Line name / number, substation name, data collection timestamp;

[0118] Phase switch position (e.g., phase A closed, phases B / C open), electrical quantity values ​​and status labels (normal / abnormal); protection trip type (overcurrent / instantaneous trip, etc.), trip phase (single-phase / two-phase / three-phase), whether it is the first trip (distinguish between the state before / after reclosing).

[0119] Anomaly labeling and prioritization: Red warning labels are added to detected abnormal states (such as protection tripping, switch position and electrical quantity inconsistencies), and the information is uploaded to the main control station first through a priority queue (to ensure that critical fault information is not delayed).

[0120] This invention employs phase-specific electrical quantity and switch position collaborative analysis to accurately identify asymmetrical faults (such as single-phase grounding causing phase A tripping), avoiding the loss of detail caused by traditional three-phase unified judgment. It distinguishes between "normal outage" and "fault disconnection" by power direction and no-load characteristics (power factor), reducing misjudgments (such as no-load lines being falsely reported as faults). Synchronous sampling ensures consistency between electrical quantities and switch status timing, avoiding logical contradictions caused by timing deviations (such as receiving a current surge before the switch disconnection signal is received). Linked verification of protection signals and electrical quantity surge characteristics reliably distinguishes between genuine fault tripping and erroneous actions (such as false triggering of protection devices). Abnormal states are pre-processed locally at the substation, reducing the amount of uploaded data while highlighting key information (such as reporting only warning tags and feature values), improving the processing efficiency of the main control station. The power direction and energy storage status in the status information provide a basis for subsequent islanding maintenance strategies (such as prioritizing the retention of loads on lines powered by energy storage).

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

[0122] Step 161: The main control station receives preset critical line activation / deactivation and tripping statuses from multiple substations. Combined with the electrical quantity fluctuations collected by the main control station on the high-voltage side, medium-voltage side, and tie lines of the main transformer, it determines whether the high-voltage side of the main transformer is disconnected from the external system.

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

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

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

[0126] In this embodiment, the main control station receives the preset critical line activation / deactivation and tripping status (such as the position of the line phase switch and protection tripping signal) uploaded by each substation, and synchronously collects the electrical quantities (voltage, current, power) of the main transformer high voltage side, medium voltage side and tie line of the station, as well as the switch position and protection tripping signal, and focuses on monitoring the sudden changes in electrical quantities (such as the current / voltage sudden rise / fall exceeding the threshold).

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

[0128] If a sudden drop in current to zero (close to 0A) is detected, and the corresponding switch position is open (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 as a whole is disconnected from the external grid).

[0129] In case of islanding, check the status of the medium-voltage side busbar and tie line of the main transformer:

[0130] If the voltage of the medium-voltage busbar on the main transformer suddenly drops to zero (indicating that the medium-voltage busbar is de-energized), and the tie line switch is in the open state (electrical connection between each substation is interrupted);

[0131] The microgrid is determined to be in a medium-voltage islanding state (the medium-voltage bus is disconnected, and the microgrid is divided into multiple independent medium-voltage zones).

[0132] Determine if a tie line is disconnected and check its status:

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

[0134] This example, through differentiated criteria for the high-voltage side, medium-voltage side, and tie lines of the main transformer, can distinguish between multiple levels of islanding, such as "main grid disconnection," "internal bus disconnection," and "substation interconnection interruption," providing precise basis for hierarchical control (e.g., large islanding requires global switching to islanding mode, while medium islanding requires zone control). Combining electrical quantity fluctuations with switch status, fault points can be located in milliseconds (e.g., a disconnection on the high-voltage side of the main transformer indicates an external fault, and disconnection of the tie line indicates a fault in the line between substations), shortening fault handling time and preventing fault propagation. By integrating substation reported data with local monitoring data from the main control station, cross-validation avoids false alarms from single devices (e.g., when a tie line switch signal of a substation is falsely alarmed, the determination can be aided by whether the electrical quantity monitored by the main control station is zero), improving the reliability of the judgment results. Different islanding states correspond to different control logics (e.g., large islanding requires activation of energy storage for global power supply, while medium islanding requires each zone to maintain power supply independently). The processing results directly drive subsequent load control, energy storage regulation, and other strategies, improving the flexibility and effectiveness of microgrid emergency response.

[0135] In an optional embodiment of the present invention, step 17, receiving the processing result through the load control station and collecting 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 islanding status, may include:

[0136] Step 171: Receive the tie-line disconnection judgment result sent by the main control station through the load control station, and simultaneously collect the tie-line current, voltage and energy storage line power direction of this station;

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

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

[0139] In this embodiment, the load control station receives the tie-line disconnection determination result sent by the master control station (i.e., the tie-line is disconnected due to fault or control command).

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

[0141] Electrical quantities of the tie line: current and voltage (to determine whether the tie line is completely de-energized);

[0142] Power direction of energy storage lines: Monitor the power flow direction of the energy storage converter (whether it is "charging" or "discharging");

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

[0144] Check the status after the contact line is disconnected:

[0145] If the tie line current is zero (indicating no current is flowing and the physical or electrical connection has been broken), and the power direction of the energy storage line is from the energy storage to the load side (i.e., the energy storage is in a "discharging" state, supplying power to the load).

[0146] Load-side isolation judgment:

[0147] Based on the local switch location information, check the electrical connection between the load side and the main grid:

[0148] If the high-voltage side switch of the main transformer is open (physically isolated from the external main grid), and the medium-voltage side or low-voltage side switch of the main transformer is closed (the load side is powered by local power), further monitor whether the electrical quantities (such as voltage and frequency) on the load side are supported only by energy storage devices 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] Conditions for determining the status of a small isolated island:

[0150] If the tie 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 local power), it is determined to be a small island state. This state information is fed back to the main control station, and the load area, energy storage node and power supply range involved are marked.

[0151] This embodiment focuses on the load-side end network. Through the linkage analysis of energy storage power direction and tie line status, it can accurately identify "independent load areas powered only by energy storage and local power sources," avoiding misjudging intermediate layer bus faults as small islands. Based on the power direction (discharge state) of energy storage lines, small islands can be determined, which can directly trigger the islanding mode switching of the energy storage system (such as switching from grid-connected control to droop control), maintaining the stability of load-side voltage and frequency, improving power supply continuity. After determining the boundary of the small island, the load control station can dynamically cut off non-critical loads (such as interruptible industrial loads) and retain critical loads (such as residential electricity) according to local criteria. The closed-loop mechanism of local data acquisition and judgment reduces the dependence on the master control station. The small island status can be quickly confirmed and fed back locally, shortening multi-level communication delays, which is especially suitable for island autonomy in communication interruption scenarios. The judgment logic is compatible with various distributed power sources (such as energy storage and photovoltaics), and the judgment criteria can be flexibly adjusted according to the actual power configuration (such as adding photovoltaic output monitoring), improving the versatility of the method and the adaptability of microgrid types.

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

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

[0154] Step 182: If the medium island determination result is valid and the large island label is invalid, then the overall island status is labeled as medium island.

[0155] Step 183: If only a small islanding state exists and the local criterion of the master station confirms that the load side is operating independently, then the total islanding state is marked as a small islanding state, and the final output is the three-level hierarchical judgment result of the large islanding, medium islanding and total islanding states.

[0156] In this embodiment, the main control station first receives and verifies the validity of the determination results of large islands, medium islands, and small islands (such as whether the signal has timed out or whether the data is complete); the priority logic is: large island > medium island > small island (that is, the higher level island status takes priority over the lower level);

[0157] Large Island marker:

[0158] If the large islanding determination result is valid (the high-voltage side of the main transformer is disconnected from the external system and the microgrid is disconnected from the grid as a whole), then the overall islanding status is directly marked as large islanding, and the determination results of medium islanding and small islanding are ignored.

[0159] Mid-island marker:

[0160] If the large islanding determination result is invalid (main network connection is normal), and the medium islanding determination result is valid (medium voltage bus is disconnected, interconnection between substations is interrupted), then the overall islanding status will be marked as medium islanding.

[0161] Small island marker:

[0162] If the results of the large islanding and medium islanding determinations are both invalid, and the load control station reports that the small islanding status is valid, and the main control station confirms through local monitoring that the electrical quantities on the load side are only supported by local power sources (such as energy storage) (without energy input from the main grid or other substations), then the total islanding status will be marked as small islanding.

[0163] Based on the above logic, a judgment result containing the following is generated: Large island status: marked "Yes / No", corresponding to the scenario of complete disconnection from the main grid; Medium island status: marked "Yes / No", corresponding to the scenario of disconnection of the medium-voltage bus and isolation between substations within the microgrid; Based on the priority, it is finally determined as a large island, medium island, or small island, and the area involved is marked (such as the main grid connection point, medium-voltage bus number, load side area).

[0164] This embodiment clarifies the islanding level through a priority mechanism, enabling the master control station to quickly match control strategies based on the overall islanding status (e.g., large islands require global activation of energy storage power supply, medium islands require zoned adjustment of tie lines, and small islands only require local load control), avoiding control failures caused by strategy confusion; the three-level hierarchical judgment can refine the islanding boundaries (e.g., distinguishing between "the entire microgrid off-grid", "internal area isolation", and "independent end loads"), helping maintenance personnel quickly locate the fault level (main grid side, bus side, or load side), shortening fault diagnosis time; it supports mixed islanding scenarios (e.g., simultaneously in a large islanding state). The system addresses the issue of islanding in microgrids. Priority coverage ensures a unique overall state, adapting to the islanding evolution process in complex microgrid topologies (e.g., multiple main transformers, multiple tie lines). Lower-level islanding states (e.g., small islands) do not require triggering global control commands; adjustments can be made solely through the local load control station, reducing the computational burden and communication bandwidth usage of the main control station and improving overall system efficiency. The three-tiered results visually represent the islanding status at each level of the microgrid, facilitating real-time display through the monitoring interface (e.g., large islands highlighted in red, medium islands in yellow, and small islands in blue), aiding operators in making rapid decisions.

[0165] like Figure 2 As shown, embodiments of the present invention also provide a microgrid system source detection system 20, comprising:

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

[0167] The identification module 22 is used to identify the grid-connected or off-grid status of the microgrid system with respect to the topology analysis results, combined with the action signals of the protection devices in each substation, the switch 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 acquisition instructions to multiple substations when an unplanned off-grid event is detected, based on the grid-connected or off-grid status.

[0169] The processing module 24 is used to respond to line status acquisition commands through multiple substations, collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determine line operation 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 electrical quantities, switch positions, and protection trip signals of the high-voltage side, medium-voltage side, and tie lines of the main transformer collected by the station, and obtains the processing result; receive the processing result through the load control station, and collect electrical quantities and switch position information of the tie lines, high and low voltage sides of the main transformer, and energy storage lines to obtain the small island status; and generate a result including the large island, medium island, and total island status based on the small island status through the main control station.

[0170] Optionally, a global topology analysis is performed based on the electrical quantities and switch position information to obtain the topology analysis results, including:

[0171] Based on the electrical quantities collected by each substation, the voltage and current correlation between nodes in the microgrid system is determined, and a dynamic topology connection matrix is ​​constructed by combining the phase switch closing / opening status in the switch position information.

[0172] Based on the dynamic topology connection matrix, the electrical connection path is analyzed by graph theory algorithm. When the electrical quantity of a branch is zero and the corresponding switch position is in the open state, it is determined that the current branch is removed from the global topology.

[0173] By integrating the branch removal status of each substation, a topology analysis result reflecting the current electrical connection relationship of the microgrid system is generated.

[0174] Optionally, a global topology analysis is performed based on the electrical quantities and switch position information to obtain the topology analysis results, including:

[0175] Based on the electrical quantities collected by each substation, the voltage and current correlation between nodes in the microgrid system is determined, and a dynamic topology connection matrix is ​​constructed by combining the phase switch closing / opening status in the switch position information.

[0176] Based on the dynamic topology connection matrix, the electrical connection path is analyzed. When the electrical quantity of the branch is zero and the corresponding switch position is in the open state, it is determined that the current branch is removed from the global topology.

[0177] By integrating the branch removal status of each substation, a topology analysis result reflecting the current electrical connection relationship of the microgrid system is generated.

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

[0179] Based on the topology analysis results, the status of the main network connection point is as follows: 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 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 that it is disconnected, the state is determined to be off-grid based on the sudden change characteristics of the fault electrical quantity.

[0181] If no planned disconnection instruction is received when disconnection occurs, it is marked as an unplanned disconnection event.

[0182] Optionally, multiple substations respond to line status acquisition commands to collect electrical quantities, phase switch positions, and protection trip signals of preset key lines, determine line activation / deactivation and tripping status, and obtain status information, including:

[0183] Each substation analyzes the line status acquisition instructions issued by the main control station, determines the target line and the parameters to be acquired, calls the local measurement and control device to synchronously sample the designated line, and collects the phase electrical quantities of the preset key line.

[0184] Collect the position of the phase switch and the protection trip signal, perform logic judgment on the switch status, and obtain the verification results of the switch / protection signal;

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

[0186] Based on the line status determination 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 the main control station, which then processes the status information in conjunction with the electrical quantities, switch positions, and protection trip signals collected by the station from the high-voltage side, medium-voltage side, and tie lines of the main transformer to obtain the processing result, including:

[0188] By receiving preset critical line activation / deactivation and tripping statuses from multiple substations via the main control station, and combining this with the electrical quantity fluctuations collected by the main control station on the high-voltage side, medium-voltage side, and tie lines of the main transformer, it is determined 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 is in the open position, a large islanding determination result is generated.

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

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

[0192] Optionally, the processing results are received through the load control station, and electrical quantities and switch position information of tie lines, high and low voltage sides of the main transformer, and energy storage lines are collected to obtain the islanding status, including:

[0193] The load control station receives the tie-line disconnection judgment result sent by the main 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 power direction of the energy storage line is from the energy storage to the load side, then the local switch position information is used to determine whether the load side is isolated from the main grid.

[0195] When the electrical quantities on the load side are supported only by energy storage and local power supply, it is determined to be in a small island state, and this state is fed back to the main control station.

[0196] Optionally, the main control station can generate results based on the small island status, including the large island, medium island, and overall island status, including:

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

[0198] If the result of the medium island determination is valid and the large island label is invalid, then the overall island status is labeled as medium island.

[0199] If only a small islanding state exists and the local criteria of the master station confirm that the load side is operating independently, then 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. All implementation methods in the above method embodiments are applicable to this embodiment and can achieve the same technical effect.

[0201] Embodiments of the present invention also provide a computing device, including: a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the method described above.

[0202] Embodiments of the present invention also provide a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform 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 recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

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

[0205] In the embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0206] The units described as separate components may or may not be physically separate. 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 the units can be selected to achieve the purpose of this embodiment according to actual needs.

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

[0208] If the aforementioned functions are implemented as 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 this invention, essentially, or the part that contributes to the prior art, or a portion 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 to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0209] Furthermore, it should be noted that in the apparatus and method of the present invention, it is obvious that the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered equivalent solutions of the present invention. Moreover, the steps performing the above-described series of processes can naturally be executed in the order described, but are not necessarily required to be executed in chronological order; some steps can be executed in parallel or independently of each other. Those skilled in the art will understand that all or any step or component of the method and apparatus of the present invention can be implemented in any computing device (including processors, storage media, etc.) or network of computing devices, in hardware, firmware, software, or a combination thereof. This is something that those skilled in the art can achieve by using their basic programming skills after reading the description of the present invention.

[0210] Therefore, the object of the present invention can also be achieved by running a program or a set of programs on any computing device. The computing device can be a known general-purpose device. Therefore, the object of the present invention can also be achieved simply by providing a program product containing program code implementing the method or apparatus. That is, 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 known storage medium or any storage medium developed in the future. It should also be noted that in the apparatus and method of the present invention, it is obvious that the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered equivalent to the present invention. Furthermore, the steps performing the above series of processes can naturally be performed in the order described, but are not necessarily required to be performed in chronological order. Some steps can be performed in parallel or independently of each other.

[0211] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting a source of a micro-grid system, applied to a source-grid-load-storage micro-grid system, and characterized in that, The method comprises: Collecting electrical quantities and switch position information of each interval of a plurality of sub-stations in a micro-grid system; Performing global topology analysis based on the electrical quantities and switch position information to obtain a topology analysis result; Based on the topology analysis result, in combination with the action signals of the protection devices in each sub-station, the switch position signals and the fault electrical quantities, identifying the grid-connected or off-grid state of the micro-grid system and the external power grid; Based on the grid-connected or off-grid state, when an unplanned off-grid of the micro-grid is identified, triggering an unplanned off-grid control strategy and sending a line state collection instruction to the plurality of sub-stations; Collecting, by the plurality of sub-stations in response to the line state collection instruction, electrical quantities, split-phase switch positions and protection tripping signals of preset key lines, discriminating line throwing and tripping states, and obtaining state information, specifically comprising: determining target lines and parameters to be collected by each sub-station analyzing the line state collection instruction issued by the master control station, calling local measurement and control devices to synchronously sample the specified lines, and collecting split-phase electrical quantities of the preset key lines; collecting split-phase switch positions and protection tripping signals, performing switch state logic judgment to obtain switch / protection signal verification results; based on the electrical quantity collection results and the switch / protection signal verification results, performing line state discrimination to obtain line state discrimination results; and generating state information containing line name, time stamp, split-phase switch position, electrical quantity state label and tripping type according to the line state discrimination results; Sending the state information to the master control station, so that the master control station processes the state information in combination with the electrical quantities, switch positions and protection tripping signals of the high-voltage side, medium-voltage side and tie line collected by the master station to obtain a processing result, specifically comprising: receiving the throwing and tripping states of the preset key lines by the master control station, in combination with the electrical quantity mutation of the high-voltage side, medium-voltage side and tie line of the master transformer collected by the master control station, determining whether the high-voltage side of the master transformer is disconnected from the external system: if the current of the high-voltage side of the master transformer suddenly drops to zero and the corresponding switch position is disconnected, a large island determination result is generated; if the voltage of the medium-voltage side of the master transformer suddenly drops to zero and the tie line switch is disconnected, a medium island determination result is generated; if the electrical quantity of the tie line is zero and the protection tripping signal is triggered, a tie line splitting determination result is generated; Receiving the processing result by 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 master transformer and the energy storage line to obtain a small island state; Generating, by the master control station based on the small island state, a result containing the large island, medium island and total island states.

2. The method of claim 1, wherein, Performing global topology analysis based on the electrical quantities and switch position information to obtain a topology analysis result, comprising: Based on the electrical quantities collected by each sub-station, determining the voltage and current correlation between each node in the micro-grid system, and constructing a dynamic topology connection matrix in combination with the split-phase switch on / off state in the switch position information; According to the dynamic topology connection matrix, analyzing the electrical connection path, and determining that the current branch is removed from the global topology when the branch electrical quantity is zero and the corresponding switch position is in the off state; Integrate the branch removal state of each substation to generate a topology analysis result reflecting the current electrical connection relationship of the micro-grid system.

3. The method of claim 1, wherein the microgrid system source is detected by, Based on the topology analysis result, in combination with the action signal of the protection device, the switch position signal and the fault electrical quantity in each substation, the grid-connected or off-grid state of the micro-grid system and the external power grid is identified, including: Based on the state of the main grid connection point in the topology analysis result: the electrical quantity at the main grid connection point is continuously non-zero and the switch position is closed, it is determined that the grid-connected state is determined; When the electrical quantity at the main grid connection point is detected to suddenly drop to zero, and the protection device action signal is triggered or the switch position signal indicates disconnection, in combination with the sudden change characteristics of the fault electrical quantity, it is determined that the off-grid state is determined; When the off-grid state occurs without receiving a planned off-grid instruction, it is marked as a non-planned off-grid event.

4. The method of claim 1, wherein, Through the load control station, receive the processing result, and collect 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, including: Through the load control station, receive the tie line splitting determination result sent by the master control station, and synchronously collect 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 direction is transmitted from the energy storage to the load side, in combination with the local switch position information, it is determined whether the load side is isolated from the main grid; When the load side electrical quantity is only supported by the energy storage and local power supply, it is determined that the small island state is determined, and the state is fed back to the master control station.

5. The method of claim 1, wherein, Based on the small island state through the master control station, generate a result including the large island, medium island and total island state, including: Through the master control station, receive the small island state fed back by the load control station, if the large island determination result is valid, the total island state is marked as a large island; If the medium island determination result is valid and the large island mark is invalid, the total island state is marked as a medium island; If only the small island state exists and the master control station local criterion confirms the load side independent operation, the total island state is marked as a small island, and finally the three-level layered determination result of the large island, medium island and total island state is output.

6. A microgrid system source detection system, comprising: Including: The acquisition module is used to acquire the electrical quantity and switch position information of each interval in the multiple substations in the micro-grid system, and perform global topology analysis based on the electrical quantity and switch position information to obtain a topology analysis result; The identification module is used to identify the grid-connected or off-grid state of the micro-grid system and the external power grid based on the topology analysis result in combination with the action signal of the protection device, the switch position signal and the fault electrical quantity in each substation; The sending module is used to trigger a non-planned off-grid control strategy when identifying that the micro-grid has a non-planned off-grid, and send a line state acquisition instruction to the multiple substations based on the grid-connected or off-grid state. The processing module is used for collecting electrical quantities, phase switch positions and protection tripping signals of preset key lines through multiple substations in response to line state collection instructions, judging line throwing and tripping states, and obtaining state information, specifically including: analyzing line state collection instructions issued by the master station through each substation, determining target lines and parameters to be collected, calling local measurement and control devices to perform synchronous sampling on specified lines, and collecting phase electrical quantities of the preset key lines; collecting phase switch positions and protection tripping signals, performing switch state logic judgment, and obtaining switch / protection signal verification results; based on the electrical quantity collection results and the switch / protection signal verification results, performing line state judgment, and obtaining line state judgment results; generating state information containing line names, time stamps, phase switch positions, electrical quantity state labels and tripping types according to the line state judgment results; and sending the state information to the master station, so that the master station processes the state information in combination with electrical quantities, switch positions and protection tripping signals of the high-voltage side, the medium-voltage side and the tie line collected by the station, obtains processing results, specifically including: receiving the throwing and tripping states of the preset key lines sent by multiple substations through the master station, and judging whether the high-voltage side of the main transformer is disconnected from the external system in combination with the electrical quantity sudden change of the high-voltage side, the medium-voltage side and the tie line collected by the master station: if the current of the high-voltage side of the main transformer suddenly drops to zero and the corresponding switch position is disconnected, a large island determination result is generated; if the voltage of the medium-voltage side of the main transformer suddenly drops to zero and the tie line switch is disconnected, a medium island determination result is generated; if the electrical quantity of the tie line is zero and the protection tripping signal is triggered, a tie line splitting determination result is generated; receiving the processing results through the load control station, and collecting 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 a small island state; and generating a result containing a large island, a medium island and a total island state based on the small island state through the master station.

7. A computing device, comprising: The processor, the memory storing a computer program, the computer program being executed by the processor to perform the method of any one of claims 1 to 5. The storage instruction, when the instruction is executed on the computer, causes the computer to perform the method of any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, ​

Images