An electrical fault logic detection method based on current-limiting characteristic parameters

Abstract

This invention relates to the field of electrical fault detection technology, and in particular to an electrical fault logic detection method based on current-limiting characteristic parameters. This method eliminates the need for external temperature sensors, achieving fault detection solely through the acquisition of pure electrical data such as voltage and current at the SSCB port. This avoids the problems of temperature sensor lag and susceptibility to interference, significantly improving the real-time performance and reliability of the detection. A two-dimensional phase trajectory discrimination method is employed, combined with a nonlinear safety boundary curve, to adapt to parameter fluctuations under different operating conditions. The method for tuning the boundary curve is also disclosed, ensuring accurate reproduction by technicians. Furthermore, the solution can be implemented using existing industrial controllers without requiring additional complex hardware. It boasts good hardware adaptability, low cost, and easy application in industrial settings, effectively enhancing the fault protection capabilities of DC microgrids.

Description

Technical Field

[0001] This invention relates to the field of electrical fault detection technology, and in particular to an electrical fault logic detection method based on current limiting characteristic parameters. Background Technology

[0002] DC microgrids, due to their advantages of high efficiency, energy saving, and adaptability to distributed power sources, are widely used in new energy power generation, rail transportation, and industrial energy storage. Solid-state circuit breakers (SSCBs), as their core protection devices, play a crucial role in fault current limiting and rapid disconnection. During the transient current-limiting process of SSCBs, the transient junction temperature rise of the current-limiting element and the dynamic equivalent impedance are strongly coupled, easily forming an "electrothermal masking effect," causing the fault current to be suppressed by the impedance and exhibit low amplitude characteristics. Traditional protection logic often relies on single parameters such as current amplitude and current change rate to identify faults, which cannot overcome this masking effect. It is easy to misjudge suppressed malicious short circuits as safe disturbances, causing protection delays or maloperation. In severe cases, it can damage power equipment and expand the fault range. Therefore, there is an urgent need for a technical solution that can achieve electrothermal decoupling and accurate fault detection.

[0003] Existing fault detection technologies for DC microgrids (SSCBs) have several shortcomings, making it difficult to meet the precise protection requirements of industrial sites. First, most solutions rely on external temperature sensors to collect junction temperature data from current-limiting components to aid in fault condition assessment. However, these sensors suffer from lag, failing to capture transient junction temperature changes in real time and are susceptible to environmental interference, resulting in biased data and an inability to promptly reflect the degree of internal electrothermal coupling. Second, existing logic is largely based on single electrical parameters, analyzing only current amplitude, voltage changes, or single impedance parameters. This fails to decouple the coupling between transient junction temperature rise and dynamic equivalent impedance. When faced with the "electrothermal masking effect," it cannot distinguish between malicious short circuits suppressed by impedance and normal safety disturbances, leading to a high false alarm rate. Third, some solutions lack effective noise suppression mechanisms. Hardware noise introduced during high-frequency sampling interferes with the judgment logic, further reducing detection accuracy. Furthermore, existing solutions often use fixed thresholds for fault discrimination, failing to adapt to parameter fluctuations under different operating conditions, exhibiting poor adaptability. Moreover, the lack of publicly available complete parameter tuning methods makes accurate reproduction difficult for technicians, limiting practicality. Summary of the Invention

[0004] The main objective of this invention is to provide an electrical fault logic detection method based on current limiting characteristic parameters, which effectively solves the problems mentioned in the background art.

[0005] The technical solution of the present invention is as follows: Firstly, a logic detection method for electrical faults based on current-limiting characteristic parameters is proposed, which includes the following steps: S1. Obtain the transient port voltage at both ends of the solid-state circuit breaker and the transient loop current flowing through the solid-state circuit breaker, and convert the transient port voltage and the transient loop current into discrete transient port voltage and discrete transient loop current based on a preset sampling time step, and then calculate the discrete transient injection power and discrete transient apparent impedance. S2. Based on the discrete transient injection power at the current moment, the discrete transient injection power at the previous moment, the sampling time step, and the discrete transient apparent impedance at the current moment, calculate the discrete transient electrothermal energy dissipation gradient, and accumulate and integrate the discrete transient electrothermal energy dissipation gradient within the sliding time window to obtain the cumulative coupling stress. S3. Calculate the discrete current change rate based on the discrete transient loop current at the current moment and the discrete transient loop current at the previous moment, and construct a two-dimensional dynamic phase plane with the discrete current change rate as the abscissa and the discrete transient electrothermal energy dissipation gradient as the ordinate. Compare the spatial position of the coordinate point at the current moment with the preset nonlinear safety boundary curve to output the real fault flag. S4. Generate a corresponding control command based on the actual fault flag bit, and output it as the final correction result to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to perform a disconnection action or maintain the conduction state.

[0006] A further improvement of the present invention is that step S1 includes the following specific steps: S11. The transient port voltage analog signal at both ends of the solid-state circuit breaker and the transient loop current analog signal flowing through the solid-state circuit breaker are synchronously acquired through the 16-bit high-precision analog-to-digital conversion module built into the microcontroller. The sampling channel of the microcontroller is electrically connected to the signal output terminals of the voltage sensor and the current sensor, respectively. S12. Discretize the acquired transient port voltage analog signal and transient loop current analog signal according to the preset sampling time step to obtain the discrete transient port voltage at time k. With discrete transient loop current The bandwidth of both the voltage sensor and the current sensor is not less than 100kHz. S13, Discrete transient port voltage based on the same sampling time With discrete transient loop current Perform a product operation to obtain the discrete transient injection power. ; S14, Based on the discrete transient port voltage With supplementary zero minimum constant The discrete transient loop current after + Performing a division operation yields the discrete transient apparent impedance. .

[0007] A further improvement of the present invention is that the following specific steps are included in step S2: S21, Based on Discrete Transient Injection Power Discrete transient apparent impedance And a preset sampling time step, and call the discrete transient injection power stored at the previous sampling time. Perform a first-order difference operation to obtain the power change rate. ; S22. The power change rate is compared with the absolute value of the discrete transient apparent impedance at the same moment. Perform a product operation to obtain the discrete transient electrothermal energy dissipation gradient. ; S23. The discrete transient electrothermal energy dissipation gradient at the current moment. Store the sequence in the internal storage array, and combine it with the preset sliding time window length N to match all sequences within the window. Perform cumulative integration to obtain the cumulative coupling stress. Where j is the discrete time index within the sliding time window, and its value ranges from kN to k; the length N of the sliding time window is 10.

[0008] A further improvement of the present invention is that step S3 includes the following specific steps: S31. Discrete transient electrothermal energy dissipation gradient based on the current moment. And based on the discrete transient loop current at the current moment. The discrete transient loop current at the previous moment Perform a first-order difference operation to obtain the discrete current rate of change. ; S32. Using the discrete current change rate as the abscissa and the discrete transient electrothermal energy dissipation gradient as the ordinate, construct a two-dimensional dynamic phase plane in the internal storage space of the microcontroller; set the coordinate point at the current moment... With the preset nonlinear safety boundary curve Perform spatial location comparison to determine whether the current operating condition is a safety disturbance or a masked malignant short-circuit fault; S33, when the coordinate point is located on the nonlinear safety boundary curve When the value is below the actual fault flag, output the true fault flag bit. When the coordinate point crosses the nonlinear safety boundary curve vertically upwards... At that time, output the actual fault flag bit. 1; wherein, the tuning method of the nonlinear safety boundary curve is: under rated operating conditions, data is collected during heavy-load start-up, line switching, and capacitor charging and discharging processes. and The maximum value is multiplied by a reliability coefficient of 1.2, and then the nonlinear safety boundary curve is obtained by polynomial fitting.

[0009] A further improvement of the present invention is that step S4 includes the following specific steps: S41, when identified When 1, the state is mapped and converted into a hard turn-off command that cuts off the gate drive signal of the solid-state circuit breaker, and the hard turn-off command is output as the final correction result to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to perform a disconnection action and cut off the fault circuit. S42, When detected At that time, the state is mapped and converted into a crossover command to maintain the gate drive signal of the solid-state circuit breaker, and this crossover command is output as the final correction result E to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to maintain the conducting state and ensure the normal power supply of the DC microgrid; wherein, the real fault flag bit is a Boolean value. 1 indicates a severe short-circuit fault. This indicates a security disturbance.

[0010] The technical effects of this invention are as follows: A novel electrical fault detection method based on current-limiting characteristic parameters has been developed. This method eliminates the need for external temperature sensors, enabling fault detection solely through the acquisition of pure electrical data such as voltage and current at the SSCB port. This avoids the lag and susceptibility to interference inherent in temperature sensors, significantly improving real-time performance and reliability. By constructing the discrete transient electrothermal energy dissipation gradient as a core feature and fusing power change rate and apparent impedance, effective decoupling of transient junction temperature rise and dynamic equivalent impedance is achieved, successfully overcoming the "electrothermal masking effect." This method can accurately identify severe short-circuit faults suppressed by impedance, completely resolving the misjudgment problem inherent in traditional logic. Accumulated coupling stress is obtained through sliding time window integration, effectively suppressing high-frequency sampling noise, improving the stability of the discrimination logic, and reducing the impact of external interference on the detection results. A two-dimensional phase trajectory discrimination method combined with a nonlinear safety boundary curve is employed to adapt to parameter fluctuations under different operating conditions. The tuning method for the boundary curve is also disclosed, ensuring accurate reproduction by technical personnel. Furthermore, the solution can be implemented based on existing industrial controllers without the need for additional complex hardware. It has good hardware compatibility, low cost, and is easy to promote and apply in industrial fields, effectively improving the fault protection capability of DC microgrids. Attached Figure Description

[0011] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1This is a flowchart illustrating an electrical fault logic detection method based on current limiting characteristic parameters according to Embodiment 1 of the present invention. Detailed Implementation

[0012] Example 1

[0013] This embodiment constructs an electrical fault logic detection method based on current-limiting characteristic parameters. It eliminates the need for external temperature sensors, achieving fault detection solely through the acquisition of pure electrical data such as voltage and current at the SSCB port. This avoids the lag and susceptibility to interference inherent in temperature sensors, significantly improving detection real-time performance and reliability. By constructing the discrete transient electrothermal energy dissipation gradient as a core feature and fusing power change rate and apparent impedance, it effectively decouples transient junction temperature rise from dynamic equivalent impedance, successfully overcoming the "electrothermal masking effect." This allows for accurate identification of severe short-circuit faults suppressed by impedance, completely resolving the misjudgment problem of traditional logic. The accumulated coupling stress is obtained through sliding time window integration, effectively suppressing high-frequency sampling noise, improving the stability of the discrimination logic, and reducing the impact of external interference on the detection results. A two-dimensional phase trajectory discrimination method is employed, combined with a nonlinear safety boundary curve, adapting to parameter fluctuations under different operating conditions. Furthermore, the boundary curve tuning method is disclosed, ensuring accurate reproduction by technical personnel. Furthermore, the solution can be implemented based on existing industrial controllers without the need for additional complex hardware. It has good hardware compatibility, low cost, and is easy to promote and apply in industrial fields, effectively improving the fault protection capability of DC microgrids.

[0014] An electrical fault logic detection method based on current limiting characteristic parameters, such as Figure 1 As shown, the specific steps include the following: S1. Obtain the transient port voltage at both ends of the solid-state circuit breaker and the transient loop current flowing through the solid-state circuit breaker, and convert the transient port voltage and the transient loop current into discrete transient port voltage and discrete transient loop current based on a preset sampling time step, and then calculate the discrete transient injection power and discrete transient apparent impedance. S2. Based on the discrete transient injection power at the current moment, the discrete transient injection power at the previous moment, the sampling time step, and the discrete transient apparent impedance at the current moment, calculate the discrete transient electrothermal energy dissipation gradient, and accumulate and integrate the discrete transient electrothermal energy dissipation gradient within the sliding time window to obtain the cumulative coupling stress. S3. Calculate the discrete current change rate based on the discrete transient loop current at the current moment and the discrete transient loop current at the previous moment, and construct a two-dimensional dynamic phase plane with the discrete current change rate as the abscissa and the discrete transient electrothermal energy dissipation gradient as the ordinate. Compare the spatial position of the coordinate point at the current moment with the preset nonlinear safety boundary curve to output the real fault flag. S4. Generate a corresponding control command based on the actual fault flag bit, and output it as the final correction result to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to perform a disconnection action or maintain the conduction state.

[0015] In this embodiment, step S1 includes the following specific steps: S11. The transient port voltage analog signal at both ends of the solid-state circuit breaker and the transient loop current analog signal flowing through the solid-state circuit breaker are synchronously acquired through the 16-bit high-precision analog-to-digital conversion module built into the microcontroller. The sampling channel of the microcontroller is electrically connected to the signal output terminals of the voltage sensor and the current sensor, respectively. S12. Discretize the acquired transient port voltage analog signal and transient loop current analog signal according to the preset sampling time step to obtain the discrete transient port voltage at time k. With discrete transient loop current The bandwidth of both the voltage sensor and the current sensor is not less than 100kHz. S13, Discrete transient port voltage based on the same sampling time With discrete transient loop current Perform a product operation to obtain the discrete transient injection power. ; S14, Based on the discrete transient port voltage With supplementary zero minimum constant The discrete transient loop current after + Performing a division operation yields the discrete transient apparent impedance. .

[0016] In this embodiment, step S2 specifically includes the following steps: S21, Based on Discrete Transient Injection Power Discrete transient apparent impedance And a preset sampling time step, and call the discrete transient injection power stored at the previous sampling time. Perform a first-order difference operation to obtain the power change rate. ; S22. The power change rate is compared with the absolute value of the discrete transient apparent impedance at the same moment. Perform a product operation to obtain the discrete transient electrothermal energy dissipation gradient. ; S23. The discrete transient electrothermal energy dissipation gradient at the current moment. Store the sequence in the internal storage array, and combine it with the preset sliding time window length N to match all sequences within the window. Perform cumulative integration to obtain the cumulative coupling stress. Where j is the discrete time index within the sliding time window, and its value ranges from kN to k; the length N of the sliding time window is 10.

[0017] In this embodiment, step S3 includes the following specific steps: S31. Discrete transient electrothermal energy dissipation gradient based on the current moment. And based on the discrete transient loop current at the current moment. The discrete transient loop current at the previous moment Perform a first-order difference operation to obtain the discrete current rate of change. ; S32. Using the discrete current change rate as the abscissa and the discrete transient electrothermal energy dissipation gradient as the ordinate, construct a two-dimensional dynamic phase plane in the internal storage space of the microcontroller; set the coordinate point at the current moment... With the preset nonlinear safety boundary curve Perform spatial location comparison to determine whether the current operating condition is a safety disturbance or a masked malignant short-circuit fault; S33, when the coordinate point is located on the nonlinear safety boundary curve When the value is below the actual fault flag, output the true fault flag bit. When the coordinate point crosses the nonlinear safety boundary curve vertically upwards... At that time, output the actual fault flag bit. 1; wherein, the tuning method of the nonlinear safety boundary curve is: under rated operating conditions, data is collected during heavy-load start-up, line switching, and capacitor charging and discharging processes. and The maximum value is multiplied by a reliability coefficient of 1.2, and then the nonlinear safety boundary curve is obtained by polynomial fitting.

[0018] In this embodiment, step S4 includes the following specific steps: S41, when identified When 1, the state is mapped and converted into a hard turn-off command that cuts off the gate drive signal of the solid-state circuit breaker, and the hard turn-off command is output as the final correction result to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to perform a disconnection action and cut off the fault circuit. S42, When detected At that time, the state is mapped and converted into a crossover command to maintain the gate drive signal of the solid-state circuit breaker, and this crossover command is output as the final correction result E to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to maintain the conducting state and ensure the normal power supply of the DC microgrid; wherein, the real fault flag bit is a Boolean value. 1 indicates a severe short-circuit fault. This indicates a security disturbance.

[0019] Example 2 This embodiment provides an electronic device, including a processor and a memory, wherein the memory stores a computer program that can be called by the processor; the processor executes the above-described electrical fault logic detection method based on current limiting characteristic parameters by calling the computer program stored in the memory.

[0020] The electronic device can vary considerably depending on its configuration or performance. It may include one or more Central Processing Units (CPUs) and one or more memories, wherein the memory stores at least one computer program, which is loaded and executed by the processor to implement the electrical fault logic detection method based on current-limiting characteristic parameters provided in the above-described embodiment. The electronic device may also include other components for implementing its functions; for example, it may have wired or wireless network interfaces and input / output interfaces for data input and output. Further details are omitted here.

[0021] Those skilled in the art will recognize that this invention can be implemented as a system, method, or computer program product. Therefore, this invention can be implemented in the following forms: it can be entirely hardware, entirely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software, generally referred to herein as a "circuit," "module," or "system." Furthermore, in some embodiments, this invention can also be implemented as a computer program product contained in one or more computer-readable media, which includes computer-readable program code.

[0022] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0023] This invention is described with reference to flowchart illustrations and block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and block diagrams, as well as combinations of blocks in the flowchart illustrations and block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart. Figure 1 One or more processes and boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0024] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and boxes Figure 1 The steps of the function specified in one or more boxes.

[0025] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method of electrical fault logic detection based on current-limited characteristic parameters, characterized by: The specific steps include the following: S1. Obtain the transient port voltage at both ends of the solid-state circuit breaker and the transient loop current flowing through the solid-state circuit breaker, and convert the transient port voltage and the transient loop current into discrete transient port voltage and discrete transient loop current based on a preset sampling time step, and then calculate the discrete transient injection power and discrete transient apparent impedance. S2. Based on the discrete transient injection power at the current moment, the discrete transient injection power at the previous moment, the sampling time step, and the discrete transient apparent impedance at the current moment, calculate the discrete transient electrothermal energy dissipation gradient, and accumulate and integrate the discrete transient electrothermal energy dissipation gradient within the sliding time window to obtain the cumulative coupling stress. S3. Calculate the discrete current change rate based on the discrete transient loop current at the current moment and the discrete transient loop current at the previous moment, and construct a two-dimensional dynamic phase plane with the discrete current change rate as the abscissa and the discrete transient electrothermal energy dissipation gradient as the ordinate. Compare the spatial position of the coordinate point at the current moment with the preset nonlinear safety boundary curve to output the real fault flag. S4. Generate a corresponding control command based on the actual fault flag bit, and output it as the final correction result to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to perform a disconnection action or maintain the conduction state.

2. The method of claim 1, wherein the method further comprises: S1 includes the following specific steps: S11. The transient port voltage analog signal at both ends of the solid-state circuit breaker and the transient loop current analog signal flowing through the solid-state circuit breaker are synchronously acquired through the 16-bit high-precision analog-to-digital conversion module built into the microcontroller. The sampling channel of the microcontroller is electrically connected to the signal output terminals of the voltage sensor and the current sensor, respectively. S12. Discretize the acquired transient port voltage analog signal and transient loop current analog signal according to the preset sampling time step to obtain the discrete transient port voltage at time k. With discrete transient loop current The bandwidth of both the voltage sensor and the current sensor is not less than 100kHz. S13, Discrete transient port voltage based on the same sampling time With discrete transient loop current Perform a product operation to obtain the discrete transient injection power. ; S14, Based on the discrete transient port voltage With supplementary zero minimum constant The discrete transient loop current after + Performing a division operation yields the discrete transient apparent impedance. .

3. The electrical fault logic detection method based on current limiting characteristic parameters according to claim 2, characterized in that: The specific steps of S2 are as follows: S21, Based on Discrete Transient Injection Power Discrete transient apparent impedance And a preset sampling time step, and call the discrete transient injection power stored at the previous sampling time. Perform a first-order difference operation to obtain the power change rate. ; S22. The power change rate is compared with the absolute value of the discrete transient apparent impedance at the same moment. Perform a product operation to obtain the discrete transient electrothermal energy dissipation gradient. ; S23. The discrete transient electrothermal energy dissipation gradient at the current moment. Store the sequence in the internal storage array, and combine it with the preset sliding time window length N to match all sequences within the window. Perform cumulative integration to obtain the cumulative coupling stress. Where j is the discrete time index within the sliding time window, and its value ranges from kN to k; the length N of the sliding time window is 10.

4. The electrical fault logic detection method based on current limiting characteristic parameters according to claim 3, characterized in that: S3 includes the following specific steps: S31. Discrete transient electrothermal energy dissipation gradient based on the current moment. And based on the discrete transient loop current at the current moment. Discrete transient loop current at the previous moment Perform a first-order difference operation to obtain the discrete current rate of change. ; S32. Using the discrete current change rate as the abscissa and the discrete transient electrothermal energy dissipation gradient as the ordinate, construct a two-dimensional dynamic phase plane in the internal storage space of the microcontroller; set the coordinate point at the current moment... With respect to the preset nonlinear safety boundary curve Perform spatial location comparison to determine whether the current operating condition is a safety disturbance or a masked malignant short-circuit fault; S33, when the coordinate point is located on the nonlinear safety boundary curve When the value is below the actual fault flag, output the true fault flag bit. When the coordinate point crosses the nonlinear safety boundary curve vertically upwards... At that time, output the actual fault flag bit. 1; wherein, the tuning method of the nonlinear safety boundary curve is as follows: under rated operating conditions, data are collected during heavy-load start-up, line switching, and capacitor charging and discharging processes. and The maximum value is multiplied by a reliability coefficient of 1.2, and then the nonlinear safety boundary curve is obtained by polynomial fitting.

5. The electrical fault logic detection method based on current limiting characteristic parameters according to claim 4, characterized in that: S4 includes the following specific steps: S41, when identified When 1, the state is mapped and converted into a hard turn-off command that cuts off the gate drive signal of the solid-state circuit breaker, and the hard turn-off command is output to the gate driver of the solid-state circuit breaker as the final correction result to control the solid-state circuit breaker to perform a disconnection action and cut off the fault circuit. S42, When detected At that time, the state is mapped and converted into a crossover command to maintain the gate drive signal of the solid-state circuit breaker, and this crossover command is output as the final correction result E to the gate driver of the solid-state circuit breaker to control the solid-state circuit breaker to maintain the conducting state and ensure the normal power supply of the DC microgrid; wherein, the actual fault flag bit is a Boolean value. 1 indicates a severe short-circuit fault. This indicates a security disturbance.

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