Coordination control method of flexible interconnection device in single-phase fault line selection of power distribution network

Abstract

The invention provides a coordination control method for a flexible interconnection device in single-phase fault line selection of a power distribution network, and the method comprises the steps: carrying out the coordination control of a flexible interconnection device in single-phase fault line selection based on a flexible interconnection power distribution system through a layered coordination architecture and a dynamic optimization strategy; full-process coordination control from fault detection, characteristic signal injection to data acquisition and analysis and fault feeder isolation operation is realized; for the FID level, a local and remote dual-mode injection signal trigger mechanism after a single-phase earth fault is designed, and a characteristic current adaptive amplitude adjustment control strategy is implemented to reduce the influence of electric energy quality while ensuring the fault characteristic intensity, and meanwhile, power frequency injection coordination control is adopted to ensure the equipment safety; and aiming at a system line selection level, designing a multi-criterion fused single-phase earth fault line identification strategy. According to the method, the line selection speed and reliability are improved, the influence on the power quality of the power grid is reduced, and an innovative solution is provided for safe operation of the flexible interconnection power distribution network.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection technology, and in particular to a coordinated control method for flexible interconnection devices in single-phase fault location in distribution networks. Background Technology

[0002] With the rapid development of medium-voltage flexible interconnected distribution networks (FIND), the limitations of traditional line selection methods in complex fault scenarios are becoming increasingly apparent. In existing technologies, the line selection method based on the characteristic signal injection of flexible interconnected devices (FID) can improve sensitivity, but it still faces the following problems in practical engineering: (1) Low efficiency of multi-device collaboration: Fault detection, signal injection, data acquisition and isolation operations rely on independent control modules and lack unified timing management, resulting in insufficient effectiveness and sensitivity of the characteristic frequency line selection method. (2) Insufficient dynamic adaptability: Under high transition resistance and complex line topology, the fixed voltage amplitude injection strategy is difficult to balance line selection sensitivity and power quality, which may lead to the submersion of characteristic signals or the occurrence of harmonic / interharmonic interference. (3) Disconnection between protection and control: The power frequency regulation function of flexible interconnected devices and line selection control lack deep integration, and control failure is easily caused by capacity and current amplitude limitations during faults. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, the first objective of this invention is to propose a coordinated control method for flexible interconnection devices in single-phase fault location in distribution networks.

[0005] The second objective of this invention is to provide a coordinated control device for flexible interconnection devices in single-phase fault location in power distribution networks.

[0006] The third objective of this invention is to provide an electronic device.

[0007] The fourth objective of this invention is to provide a computer-readable storage medium.

[0008] The fifth objective of this invention is to provide a computer program product.

[0009] To achieve the above objectives, a first aspect of the present invention provides a coordinated control method for flexible interconnection devices in single-phase fault location in distribution networks, comprising:

[0010] S1 constructs a two-layer collaborative architecture between the local control layer of the flexible interconnected device and the master station layer of the power distribution automation. The local control layer integrates fault detection, signal injection and power coordination modules, while the master station layer is responsible for signal acquisition, line selection decision and isolation command issuance. The two achieve data interaction through a communication link.

[0011] S2, based on the local control layer, real-time monitoring of phase voltage drop and zero-sequence voltage over-limit of common connection point, enters the delay confirmation window after the triggering condition is met, and verifies the zero-sequence voltage over-limit condition again. If it is met, the characteristic frequency signal injection is triggered. Otherwise, the average zero-sequence voltage in the delay window is further verified to avoid misjudgment. At the same time, after the master station layer determines a single-phase ground fault, it sends a remote trigger injection command to the flexible interconnection device through the communication channel.

[0012] S3, dynamically calculates the target characteristic current amplitude based on the injection time of the trigger signal, adjusts the injected current amplitude in real time based on the equivalent impedance of the fault point, and sets upper and lower limits of the current to take into account both the fault characteristic intensity and power quality.

[0013] S4 generates an additional voltage command and superimposes it onto the power frequency voltage modulation wave. It generates a switch trigger signal for the flexible interconnection device through PWM modulation to realize the injection of characteristic frequency signals. After the injection duration reaches the preset duration, it automatically blocks the characteristic current injection. At the same time, it introduces a measurement delay window to start steady-state signal acquisition. The master station layer calculates the main criteria for line selection based on the acquired data and judges the faulty line. If the signal acquisition is abnormal, it switches to the backup criteria for fault identification.

[0014] Optionally, S2 further includes:

[0015] For local triggering, the phase voltage drop and zero-sequence voltage limit exceedance at the point of common coupling are monitored in real time. If the above triggering conditions are met, a delayed confirmation window T1 is introduced to avoid transient interference. After T1 is completed, the zero-sequence voltage limit exceedance condition is verified again. If it is still met, the characteristic frequency signal is injected. If it is not met, the mean value of the zero-sequence voltage during T1 is further verified to avoid misjudgment of arc fault. If the mean value meets the zero-sequence voltage limit exceedance condition, the characteristic frequency signal is injected in the same way.

[0016] For remote triggering, as a backup protection for systems equipped with distribution automation technology, after the master station determines a single-phase ground fault based on the measurement data of the distributed intelligent terminal, it sends a characteristic signal injection command to the FID through the communication channel.

[0017] Optionally, S3 further includes:

[0018] Once the characteristic frequency signal is triggered, the target current amplitude I is calculated. FID,inj The magnitude of the target injected current is calculated according to the following formula:

[0019]

[0020] In the formula, The upper limit of the injection current, Z is the lower limit of the injection current. eq Z is the equivalent impedance of the grid connection point after the fault. eq,HIFThe equivalent impedance of the grid connection point corresponding to a 1kΩ high-resistance ground fault;

[0021] An additional voltage command U is generated using a constant current controller. FID,inj , and target current command I FID,inj The following relationship must be satisfied:

[0022] U FID,inj =k T |Z eq |I FID,inj

[0023] In the formula, k T This refers to the turns ratio of the converter transformer;

[0024] The formula for generating a three-phase symmetrical sinusoidal voltage modulation wave is as follows:

[0025]

[0026] In the formula, These are the additional voltage signals corresponding to A, B, and C, respectively, ω inj To inject the signal angular frequency, The initial phase of the additional voltage signal;

[0027] Calculate the power frequency active current i d reactive current i q The instruction, formula is:

[0028]

[0029] In the formula, u FID , For FID grid connection point phase voltage, there are named values ​​and per-unit values; P ref Q ref These are the active power and reactive power commands for the converter, respectively; I N For FID rated current; i lmt K1 and K2 are the converter limiting values; K1 and K2 are the reactive power compensation coefficients.

[0030] Optionally, S4 further includes:

[0031] The generated characteristic frequency voltage modulation wave is superimposed on the power frequency modulation wave, and the superimposed voltage modulation wave is modulated by PWM to generate the FID switch trigger signal, thereby realizing the injection of characteristic frequency signal.

[0032] The FID injection characteristic frequency signal is set to last for T2, and the characteristic current injection is automatically blocked at time t+T2, where time t is the injection time of the characteristic frequency signal.

[0033] The measurement delay window T3 is set, and the feeder terminal unit configured at each feeder outgoing switch starts steady-state signal acquisition at the delay t+T3 time. The characteristic frequency components are extracted by Fourier transform, and the main station summarizes the data through the communication network.

[0034] The master station calculates the main criteria for line selection for each line based on the feeder summary data, identifies the faulty feeder, and defines the line selection discrimination index K. d for:

[0035]

[0036] In the formula, the symbol M represents the line selection criterion value; M f M kmax These represent the criterion values ​​for the faulty line and the maximum criterion value for the healthy line, respectively; the main criterion for line selection is the amplitude of the zero-sequence characteristic frequency current, when K... d If the value is greater than 1, the line is considered faulty.

[0037] If signal acquisition is abnormal or communication is interrupted, the master station switches to the backup criterion. The line selection criterion for the phase criterion is the zero-sequence characteristic current phase discrimination, which is defined as follows:

[0038]

[0039] In the formula, n is the total number of feeders; θ isig θ jsig These are the characteristic frequencies of the zero-sequence current phase detected at the i and j outlets of the line, respectively. When the K of the feeder... d If the value is n-1, it is determined to be a faulty feeder;

[0040] The active power criterion for line selection is the active power at the zero-sequence characteristic frequency. When the K of the feeder... d <0 or |K d If |≥1, it is determined to be a faulty feeder;

[0041] After the master station determines the faulty line based on the primary or backup criteria, it sends a tripping command to the circuit breaker of the faulty feeder to achieve isolation of the single-phase grounding feeder.

[0042] To achieve the above objectives, a second aspect of the present invention provides a coordinated control device for flexible interconnection devices in single-phase fault location in a distribution network, comprising:

[0043] The dual-layer collaborative architecture construction module is used to build a dual-layer collaborative architecture between the local control layer of the flexible interconnection device and the master station layer of the power distribution automation. The local control layer integrates fault detection, signal injection and power coordination modules, while the master station layer is responsible for signal acquisition, line selection decision and isolation command issuance. The two achieve data interaction through a communication link.

[0044] The fault triggering and signal injection control module is used to monitor the phase voltage drop and zero-sequence voltage over-limit of the common connection point in real time based on the local control layer. After the triggering condition is met, it enters the delay confirmation window to verify the zero-sequence voltage over-limit condition again. If it is met, the characteristic frequency signal injection is triggered. Otherwise, the average zero-sequence voltage in the delay window is further verified to avoid misjudgment. At the same time, after the master station layer determines a single-phase ground fault, it sends a remote triggering injection command to the flexible interconnection device through the communication channel.

[0045] The characteristic current amplitude dynamic adjustment module is used to dynamically calculate the target characteristic current amplitude according to the injection time of the trigger signal, adjust the injected current amplitude in real time based on the equivalent impedance of the fault point, and set the upper and lower limits of the current to take into account both the fault characteristic intensity and power quality.

[0046] The signal injection and steady-state acquisition control module is used to generate additional voltage commands and superimpose them onto the power frequency voltage modulation wave. It generates a switching trigger signal for the flexible interconnect device through PWM modulation to realize the injection of characteristic frequency signals. After the injection duration reaches the preset duration, it automatically blocks the characteristic current injection. At the same time, a measurement delay window is introduced to start steady-state signal acquisition. The master station layer calculates the main criteria for line selection based on the acquired data and identifies the faulty line. If the signal acquisition is abnormal, it switches to the backup criteria for fault identification.

[0047] To achieve the above objectives, a third aspect of the present invention provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor;

[0048] The memory stores computer-executed instructions;

[0049] The processor executes computer execution instructions stored in the memory to implement the method as described in any one of the first aspects.

[0050] To achieve the above objectives, a fourth aspect of the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of the first aspects.

[0051] To achieve the above objectives, a fifth aspect of the present invention provides a computer program product that, when executed by a processor, implements the method described in any one of the first aspects.

[0052] The technical solutions provided by the embodiments of the present invention bring at least the following beneficial effects: The hierarchical collaborative control involved in the present invention achieves efficient synchronization of fault detection, signal injection, and isolation operation through a two-layer architecture of local and master stations, effectively reducing the risk of mismatch in each link. The adaptive amplitude adjustment control involved combines the transition resistance to dynamically adjust the injection current, taking into account both high-resistance fault sensitivity and low-resistance power quality. The coordinated control of the power frequency and characteristic frequency signals involved ensures the effective output of the characteristic frequency line selection signal, while realizing low-voltage ride-through control and power flow regulation control of the power frequency output, fully tapping the regulation potential of FID. The multi-criteria fusion involved improves the line selection reliability under complex operating conditions through complementary amplitude, phase, and active power criteria. The method involved in the present invention is entirely based on the existing hardware architecture of FID, and achieves functional upgrades through algorithm optimization of its control strategy, which has good engineering promotion value. In addition, the method has strong compatibility, is adapted to neutral point ungrounded / resonant grounded systems, and supports the expansion of multi-terminal flexible interconnection topologies.

[0053] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0054] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0055] Figure 1 This is a flowchart illustrating a coordinated control method for a flexible interconnection device in single-phase fault location in a power distribution network, as provided in an embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram of the coordinated control of the characteristic frequency and power frequency injection of FID provided in an embodiment of the present invention;

[0057] Figure 3 This is a flowchart of a single-phase fault line selection method using FID injection of characteristic frequency current provided in an embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of the structure of a flexible interconnection device for coordinating and controlling a single-phase fault location in a power distribution network, as provided in an embodiment of the present invention. Detailed Implementation

[0059] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0060] Figure 1 This is a flowchart illustrating a coordinated control method for a flexible interconnection device in single-phase fault location in a power distribution network, as provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the coordinated control of the characteristic frequency and power frequency injection of FID provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating single-phase fault line selection using FID injection of characteristic frequency current, provided in an embodiment of the present invention.

[0061] Reference Figure 1 , 2 And 3, the method includes the following steps:

[0062] S1 constructs a two-layer collaborative architecture between the local control layer of the flexible interconnected device and the master station layer of the power distribution automation. The local control layer integrates fault detection, signal injection and power coordination modules, while the master station layer is responsible for signal acquisition, line selection decision and isolation command issuance. The two achieve data interaction through a communication link.

[0063] In this embodiment, a two-layer collaborative architecture for the Flexible Interconnect Device (FID) is first constructed, consisting of a local control layer and a distribution automation master station layer. This architecture, through effective hierarchical division and modular design, ensures efficient collaboration between fault detection, signal injection, and power coordination.

[0064] Specifically, the local control layer integrates a fault detection module, a signal injection module, and a power coordination module. The fault detection module monitors electrical parameters in the distribution network in real time, and when a single-phase ground fault occurs, it can quickly detect the fault and trigger subsequent operations. The signal injection module is responsible for injecting characteristic frequency signals according to the fault type and specific requirements to ensure accurate identification of the faulty line. The power coordination module, when a fault occurs, adjusts power distribution and controls current to ensure that power quality is not excessively affected and to avoid secondary damage to the power grid.

[0065] The master station layer is primarily responsible for signal acquisition, line selection decisions, and issuing fault isolation commands. Through real-time data interaction with the local control layer, the master station layer receives electrical parameters and fault signals from the local control layer and uses this information to identify faulty lines and make line selection decisions. Line selection decisions are mainly based on multi-dimensional criteria, quickly and accurately identifying faulty lines by comparing the electrical characteristics of different feeders. The master station layer is also responsible for sending isolation commands to relevant circuit breakers to ensure that faulty lines are isolated in the shortest possible time, preventing the fault from spreading to other parts.

[0066] Data exchange between the two layers is achieved through a stable communication link, ensuring efficient transmission of fault information and timely execution of decision-making instructions. The communication link not only transmits fault detection results and signal injection information but also transmits real-time system operating status, ensuring seamless connection and efficient operation of the entire coordinated control process. This two-layer collaborative architecture leverages the flexibility of the local control layer in fault detection and response while utilizing the powerful decision-making capabilities of the master station layer, achieving the safe and stable operation of the distribution network.

[0067] S2, based on the local control layer, monitors the phase voltage drop and zero-sequence voltage limit of the common connection point in real time. After the triggering condition is met, it enters the delay confirmation window to verify the zero-sequence voltage limit condition again. If it is met, the characteristic frequency signal injection is triggered. Otherwise, the average zero-sequence voltage in the delay window is further verified to avoid misjudgment. At the same time, after the master station layer determines a single-phase ground fault, it sends a remote trigger injection command to the flexible interconnection device through the communication channel.

[0068] In the embodiments of this application, the design of the triggering mechanism is divided into two modes: local triggering and remote triggering.

[0069] Local Triggering: The local control layer determines whether a fault has occurred by real-time monitoring of phase voltage dips and zero-sequence voltage exceedances at the point of common coupling (PCC). Specifically, when the phase voltage dips below 0.85 pu and the zero-sequence voltage exceeds 0.15 pu, the triggering condition is met, and the initial fault detection phase begins. To avoid misjudgments due to transient disturbances, a delayed confirmation window T1 is introduced. This window represents a certain time delay to ensure that the zero-sequence voltage is re-verified after system stability to ensure it does not exceed 0.15 pu. If the condition is still met, the injection of a characteristic frequency signal is further triggered to help accurately identify the faulty line.

[0070] During the delayed confirmation window T1, if the zero-sequence voltage condition is not continuously met, the average zero-sequence voltage during T1 is verified again. If the average exceeds 0.15 pu, the characteristic frequency signal injection is still triggered, thereby ensuring that the system can accurately identify single-phase ground faults and avoid the possibility of misjudging arc faults. Through this redundant detection method, erroneous judgments caused by instantaneous fluctuations in the power grid can be better avoided, improving the reliability and accuracy of fault detection.

[0071] Remote triggering serves as a backup protection function at the master station level. The master station determines whether a single-phase ground fault has occurred in the system based on measurement data from distributed intelligent terminals. When a fault occurs, the master station sends a characteristic signal injection command to the Flexible Interconnect Device (FID) at the local control layer via a communication channel. The remote triggering mechanism provides additional backup protection for the distribution network, ensuring that even if the local detection system fails to trigger in a timely manner, the master station can still intervene and perform necessary interventions, thereby improving the system's fault response speed and accuracy.

[0072] This dual-trigger mechanism combines the real-time response capability of the local control layer with the remote intervention capability of the master station layer, enhancing the system's fault tolerance and the reliability of fault detection. It can respond promptly to various possible fault scenarios, ensuring the stable and safe operation of the distribution network.

[0073] S3 dynamically calculates the target characteristic current amplitude based on the injection time of the trigger signal, adjusts the injected current amplitude in real time based on the equivalent impedance of the fault point, and sets upper and lower limits for the current to balance the fault characteristic intensity and power quality.

[0074] In this embodiment, regarding the injection time of the characteristic frequency signal, once signal injection is triggered, the amplitude of the target characteristic current is dynamically calculated to ensure the fault characteristic intensity while avoiding power quality deterioration. The specific implementation steps are as follows:

[0075] When the characteristic frequency signal is injected, the target current amplitude I needs to be calculated first. FID,inj The target current amplitude is adjusted in real time based on the equivalent impedance of the fault point to adapt to different fault types and transition resistances. The formula for calculating the target current amplitude is as follows:

[0076]

[0077] In the formula, The upper limit of the injection current, Z is the lower limit of the injection current. eq Z is the equivalent impedance of the grid connection point after the fault. eq,HIF This represents the equivalent impedance at the grid connection point corresponding to a 1kΩ high-resistance ground fault. This formula ensures that, within the allowable range of power quality, the characteristic current amplitude is dynamically adjusted according to the specific fault situation, thus guaranteeing the fault characteristic strength while reducing the impact on grid stability. The upper and lower limits of the injected current are set to balance the requirements of fault characteristic strength and power quality; the upper current limit... Used to prevent power quality deterioration and to prevent excessive current from adversely affecting the system; current lower limit Ensure measurement accuracy so that signal injection is not affected by changes in system current.

[0078] Furthermore, based on the target current command IFID,inj An additional voltage command U is generated using a constant current controller. FID,inj And ensure that it satisfies the following relationship:

[0079]

[0080] In the formula, k T This refers to the turns ratio of the converter transformer. This relationship ensures that corresponding voltage commands are generated based on changes in the target current amplitude and the fault point impedance, thereby achieving effective regulation of the grid current.

[0081] To inject an additional voltage signal into the power grid, this invention generates a three-phase symmetrical sinusoidal voltage wave through modulation. The generation formula is as follows:

[0082]

[0083] In the formula, These are the additional voltage signals corresponding to A, B, and C, respectively, ω inj To inject the signal angular frequency, This is the initial phase of the additional voltage signal.

[0084] During a fault, this invention prioritizes the injection of characteristic current, especially in Low Voltage Ride-Through (LVRT) mode, where reactive current is preferentially injected to support the voltage. Simultaneously, to protect the converter's safety, the power frequency active current is dynamically limited within the converter's safety margin. Power frequency active current i d reactive current i q The formula for calculating the instruction is as follows:

[0085]

[0086] In the formula, u FID , For FID grid connection point phase voltage, there are named values ​​and per-unit values; P ref Q ref These are the active power and reactive power commands for the converter, respectively; I N For FID rated current; i lmt K1 and K2 are the converter limiting values; K1 and K2 are the reactive power compensation coefficients.

[0087] By employing a dual closed-loop structure of outer-loop power control and inner-loop current control, this invention generates three-phase voltage modulation waves at the power frequency. These modulation waves, combined with additional voltage signals at characteristic frequencies, optimize the injection and control of fault current while ensuring power quality and system stability.

[0088] By taking the above steps, the intensity of the fault characteristics is ensured, the negative impact on the power quality of the power grid is avoided, and the system is able to effectively respond to various fault conditions, ensuring the safe and stable operation of the power grid.

[0089] S4 generates an additional voltage command and superimposes it onto the power frequency voltage modulation wave. It generates a switch trigger signal for the flexible interconnection device through PWM modulation to realize the injection of characteristic frequency signals. After the injection duration reaches the preset duration, it automatically blocks the characteristic current injection. At the same time, it introduces a measurement delay window to start steady-state signal acquisition. The master station layer calculates the main criteria for line selection based on the acquired data and judges the faulty line. If the signal acquisition is abnormal, it switches to the backup criteria for fault identification.

[0090] In this embodiment of the application, the following specific steps are taken to achieve accurate injection of characteristic frequency signals and efficient identification of faulty lines:

[0091] First, the generated characteristic frequency voltage modulation wave is superimposed on the power frequency modulation wave. The superimposed voltage modulation wave is then modulated by PWM to generate the FID switch trigger signal, thus realizing the characteristic frequency signal injection. To avoid the adverse effects of prolonged characteristic current injection on the system, this signal injection will last for a preset time T2. Once T2 is reached, the system will automatically block the characteristic current injection, thereby avoiding the negative impact of prolonged signal injection on system stability.

[0092] To avoid interference from transient currents, the system sets a measurement delay window T3. Within this window, feeder terminal units (FTUs) are configured at the outgoing switches of each feeder. These units initiate steady-state signal acquisition at the delay time (t+T3) and extract characteristic frequency components through Fourier transform. Time t is the injection time of the characteristic frequency signal. The master station layer aggregates the steady-state signal data of each feeder through the communication network and uses this data to determine subsequent fault lines.

[0093] Based on the aggregated data, the main station calculates the primary selection criterion for each feeder and identifies the faulty line. The primary selection criterion is calculated based on the zero-sequence characteristic frequency current amplitude, and a selection discrimination index K is defined. d for:

[0094]

[0095] In the formula, the symbol M represents the line selection criterion value; M f M kmax These represent the criterion values ​​for the faulty line and the maximum criterion value for the healthy line, respectively; the main criterion for line selection is the amplitude of the zero-sequence characteristic frequency current, when K... d A value greater than 1 indicates a faulty line. Using this criterion, the master station can accurately identify faulty lines and then perform isolation operations.

[0096] If an anomaly or communication interruption occurs during signal acquisition, the master station will switch to backup criteria for fault identification. Backup criteria include phase criteria and active power criteria, wherein:

[0097] The selection criterion for the phase criterion is the zero-sequence characteristic current phase discrimination, and the zero-sequence characteristic current phase discrimination of feeder i is defined as:

[0098]

[0099] In the formula, n is the total number of feeders; θ isig θ jsig These are the characteristic frequencies of the zero-sequence current phase detected at the i and j outlets of the line, respectively. When the K of the feeder... d If the value is n-1, it is determined to be a faulty feeder;

[0100] The active power criterion for line selection is the active power at the zero-sequence characteristic frequency. When the K of the feeder... d <0 or |K d If |≥1, it is determined to be a faulty feeder.

[0101] Based on the primary or backup criteria, the master station determines the faulty line and sends a tripping command to the circuit breaker of the faulty feeder, thus isolating the single-phase grounded feeder. This operation can quickly disconnect the faulty line, preventing the fault from spreading to other parts and ensuring the stability and safe operation of the distribution network.

[0102] Through the above steps, the system can efficiently and accurately identify and isolate faulty lines, reduce the impact of faults on the power grid, and ensure the continuous and stable operation of the system.

[0103] To achieve the above embodiments, the present invention also proposes a coordination control device for flexible interconnection devices in single-phase fault location in distribution networks. Figure 4 This is a schematic diagram of the structure of a coordinated control device for a flexible interconnection device in single-phase fault location in a distribution network, provided as an embodiment of the present invention. Figure 4 As shown, the device includes:

[0104] The dual-layer collaborative architecture construction module is used to build a dual-layer collaborative architecture between the local control layer of the flexible interconnection device and the master station layer of the power distribution automation. The local control layer integrates fault detection, signal injection and power coordination modules, while the master station layer is responsible for signal acquisition, line selection decision and isolation command issuance. The two achieve data interaction through a communication link.

[0105] The fault triggering and signal injection control module is used to monitor the phase voltage drop and zero-sequence voltage over-limit of the common connection point in real time based on the local control layer. After the triggering condition is met, it enters the delay confirmation window to verify the zero-sequence voltage over-limit condition again. If it is met, the characteristic frequency signal injection is triggered. Otherwise, the average zero-sequence voltage in the delay window is further verified to avoid misjudgment. At the same time, after the master station layer determines a single-phase ground fault, it sends a remote triggering injection command to the flexible interconnection device through the communication channel.

[0106] The characteristic current amplitude dynamic adjustment module is used to dynamically calculate the target characteristic current amplitude according to the injection time of the trigger signal, adjust the injected current amplitude in real time based on the equivalent impedance of the fault point, and set the upper and lower limits of the current to take into account both the fault characteristic intensity and power quality.

[0107] The signal injection and steady-state acquisition control module is used to generate additional voltage commands and superimpose them onto the power frequency voltage modulation wave. It generates a switching trigger signal for the flexible interconnect device through PWM modulation to realize the injection of characteristic frequency signals. After the injection duration reaches the preset duration, it automatically blocks the characteristic current injection. At the same time, a measurement delay window is introduced to start steady-state signal acquisition. The master station layer calculates the main criteria for line selection based on the acquired data and identifies the faulty line. If the signal acquisition is abnormal, it switches to the backup criteria for fault identification.

[0108] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0109] To implement the above embodiments, the present invention also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0110] To implement the above embodiments, the present invention also proposes a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0111] To implement the above embodiments, the present invention also proposes a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0112] The collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in this invention all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0113] It should be noted that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. Furthermore, such collection / sharing should only be conducted after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes authorization of relevant user information before the user uses the function. In addition, any necessary steps must be taken to protect and safeguard access to such personal information data and ensure that others with access to personal information data comply with their privacy policies and procedures.

[0114] This invention is intended to provide implementation schemes for users to selectively prevent the use or access to personal information data. That is, this disclosure is intended to provide hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, risks can be minimized by restricting data collection and deleting data. Furthermore, where applicable, such personal information can be de-identified to protect user privacy.

[0115] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0116] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0117] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0118] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0119] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0120] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0121] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0122] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0123] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0124] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A coordinated control method for flexible interconnection devices in single-phase fault location in distribution networks, characterized in that, Includes the following steps: S1 constructs a two-layer collaborative architecture between the local control layer of the flexible interconnected device and the master station layer of the power distribution automation. The local control layer integrates fault detection, signal injection and power coordination modules, while the master station layer is responsible for signal acquisition, line selection decision and isolation command issuance. The two achieve data interaction through a communication link. S2, based on the local control layer, real-time monitoring of phase voltage drop and zero-sequence voltage over-limit of common connection point, enters the delay confirmation window after the triggering condition is met, and verifies the zero-sequence voltage over-limit condition again. If it is met, the characteristic frequency signal injection is triggered. Otherwise, the average zero-sequence voltage in the delay window is further verified to avoid misjudgment. At the same time, after the master station layer determines a single-phase ground fault, it sends a remote trigger injection command to the flexible interconnection device through the communication channel. S3, dynamically calculates the target characteristic current amplitude based on the injection time of the trigger signal, adjusts the injected current amplitude in real time based on the equivalent impedance of the fault point, and sets upper and lower limits of the current to take into account both the fault characteristic intensity and power quality. S4 generates an additional voltage command and superimposes it onto the power frequency voltage modulation wave. It generates a switch trigger signal for the flexible interconnection device through PWM modulation to realize the injection of characteristic frequency signals. After the injection duration reaches the preset duration, it automatically blocks the characteristic current injection. At the same time, it introduces a measurement delay window to start steady-state signal acquisition. The master station layer calculates the main criteria for line selection based on the acquired data and judges the faulty line. If the signal acquisition is abnormal, it switches to the backup criteria for fault identification.

2. The method according to claim 1, characterized in that, The S2 further includes: For local triggering, the phase voltage drop and zero-sequence voltage limit exceedance at the point of common coupling are monitored in real time. If the above triggering conditions are met, a delayed confirmation window T1 is introduced to avoid transient interference. After T1 is completed, the zero-sequence voltage limit exceedance condition is verified again. If it is still met, the characteristic frequency signal is injected. If it is not met, the mean value of the zero-sequence voltage during T1 is further verified to avoid misjudgment of arc fault. If the mean value meets the zero-sequence voltage limit exceedance condition, the characteristic frequency signal is injected in the same way. For remote triggering, as a backup protection for systems equipped with distribution automation technology, after the master station determines a single-phase ground fault based on the measurement data of the distributed intelligent terminal, it sends a characteristic signal injection command to the FID through the communication channel.

3. The method according to claim 2, characterized in that, The S3 further includes: Once the characteristic frequency signal is triggered, the target current amplitude I is calculated. FID,inj The magnitude of the target injected current is calculated according to the following formula: In the formula, The upper limit of the injection current, Z is the lower limit of the injection current. eq Z is the equivalent impedance of the grid connection point after the fault. eq,HIF The equivalent impedance of the grid connection point corresponding to a 1kΩ high-resistance ground fault; An additional voltage command U is generated using a constant current controller. FID,inj , and the target current command i FID,inj The following relationship must be satisfied: U FID,inj =k T |Z eq |I FID,inj In the formula, k T This refers to the turns ratio of the converter transformer; The formula for generating a three-phase symmetrical sinusoidal voltage modulation wave is as follows: In the formula, These are the additional voltage signals corresponding to A, B, and C, respectively, ω inj To inject the signal angular frequency, The initial phase of the additional voltage signal; Calculate the power frequency active current i d reactive current i q The instruction, formula is: In the formula, u FID , For FID grid connection point phase voltage, there are named values ​​and per-unit values; P ref Q ref These are the active power and reactive power commands for the converter, respectively; I N For FID rated current; i lmt K1 and K2 are the converter limiting values; K1 and K2 are the reactive power compensation coefficients.

4. The method according to claim 3, characterized in that, The S4 further includes: The generated characteristic frequency voltage modulation wave is superimposed on the power frequency modulation wave, and the superimposed voltage modulation wave is modulated by PWM to generate the FID switch trigger signal, thereby realizing the injection of characteristic frequency signal. The FID injection characteristic frequency signal is set to last for T2, and the characteristic current injection is automatically blocked at time t+T2, where time t is the injection time of the characteristic frequency signal. The measurement delay window T3 is set, and the feeder terminal unit configured at each feeder outgoing switch starts steady-state signal acquisition at the delay t+T3 time. The characteristic frequency components are extracted by Fourier transform, and the main station summarizes the data through the communication network. The master station calculates the main criteria for line selection for each line based on the feeder summary data, identifies the faulty feeder, and defines the line selection discrimination index K. d for: In the formula, the symbol M represents the line selection criterion value; M f M kmax These represent the criterion values ​​for the faulty line and the maximum criterion value for the healthy line, respectively; the main criterion for line selection is the amplitude of the zero-sequence characteristic frequency current, when K... d If the value is greater than 1, the line is considered faulty. If signal acquisition is abnormal or communication is interrupted, the master station switches to the backup criterion. The line selection criterion for the phase criterion is the zero-sequence characteristic current phase discrimination, which is defined as follows: In the formula, n is the total number of feeders; θ isig θ jsig These are the characteristic frequencies of the zero-sequence current phase detected at the i and j outlets of the line, respectively. When the K of the feeder... d If the value is n-1, it is determined to be a faulty feeder; The active power criterion for line selection is the active power at the zero-sequence characteristic frequency. When the K of the feeder... d <0 or |K d If |≥1, it is determined to be a faulty feeder; After the master station determines the faulty line based on the primary or backup criteria, it sends a tripping command to the circuit breaker of the faulty feeder to achieve isolation of the single-phase grounding feeder.

5. A coordinated control device for flexible interconnection devices in single-phase fault location in distribution networks, characterized in that, include: The dual-layer collaborative architecture construction module is used to build a dual-layer collaborative architecture between the local control layer of the flexible interconnection device and the master station layer of the power distribution automation. The local control layer integrates fault detection, signal injection and power coordination modules, while the master station layer is responsible for signal acquisition, line selection decision and isolation command issuance. The two achieve data interaction through a communication link. The fault triggering and signal injection control module is used to monitor the phase voltage drop and zero-sequence voltage over-limit of the common connection point in real time based on the local control layer. After the triggering condition is met, it enters the delay confirmation window to verify the zero-sequence voltage over-limit condition again. If it is met, the characteristic frequency signal injection is triggered. Otherwise, the average zero-sequence voltage in the delay window is further verified to avoid misjudgment. At the same time, after the master station layer determines a single-phase ground fault, it sends a remote triggering injection command to the flexible interconnection device through the communication channel. The characteristic current amplitude dynamic adjustment module is used to dynamically calculate the target characteristic current amplitude according to the injection time of the trigger signal, adjust the injected current amplitude in real time based on the equivalent impedance of the fault point, and set the upper and lower limits of the current to take into account both the fault characteristic intensity and power quality. The signal injection and steady-state acquisition control module is used to generate additional voltage commands and superimpose them onto the power frequency voltage modulation wave. It generates a switching trigger signal for the flexible interconnect device through PWM modulation to realize the injection of characteristic frequency signals. After the injection duration reaches the preset duration, it automatically blocks the characteristic current injection. At the same time, a measurement delay window is introduced to start steady-state signal acquisition. The master station layer calculates the main criteria for line selection based on the acquired data and identifies the faulty line. If the signal acquisition is abnormal, it switches to the backup criteria for fault identification.

6. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-4.

8. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method of any one of claims 1-4.

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