An insulation detection control method and system based on a high-voltage direct-current power supply system

Abstract

The application provides an insulation detection control method and system based on a high-voltage direct-current power supply system, relates to the technical field of insulation detection and fault control of the high-voltage direct-current power supply system, and solves the technical problem of inaccurate fault positioning in the prior art. The method comprises the following steps: dividing a direct-current bus into multiple sub-zones and setting contactors; injecting a sweep signal between the positive and negative buses and the ground wire, collecting impedance response of each sub-zone; calculating the insulation deterioration degree based on the impedance response, injecting a synchronous traveling wave signal when the insulation deterioration degree exceeds a threshold; collecting the time difference of the arrival of the traveling wave at the first and last ends, and calculating the fault point position; and disconnecting the contactor of the corresponding sub-zone according to the fault point position, so as to realize sub-zone isolation. The application is used in the insulation state monitoring, accurate fault positioning and sub-zone isolation, fault type identification and system operation reliability optimization process of the high-voltage direct-current power supply system.

Description

Technical Field

[0001] This invention belongs to the field of insulation detection and fault control of high voltage DC power supply systems, specifically an insulation detection and control method and system based on high voltage DC power supply systems. Background Technology

[0002] In high-voltage direct current (HVDC) power supply systems, insulation testing is a crucial step in ensuring stable and safe system operation. It involves continuous monitoring of the insulation condition of the DC bus and related equipment, using various technical methods to quantify and analyze insulation performance indicators. This allows for the early detection of aging and damage to insulation materials, as well as potential grounding fault risks. If any insulation abnormalities are detected, the system can promptly issue an alarm, preventing leakage and short circuits caused by insulation problems, preventing irreversible damage to equipment, and ensuring the continuity and reliability of the power supply.

[0003] In terms of fault location, traditional two-end traveling wave location methods calculate the fault distance by utilizing the time difference between the arrival times of the traveling wave at both ends of the line, but often assume that the traveling wave velocity is constant. However, actual high-voltage DC busbars are dispersive media, and the wave velocities of different frequency components vary when the traveling wave propagates within them. The assumption of a constant wave velocity introduces a large error, which leads to a significant reduction in location accuracy and fails to meet the requirements for precise location. Summary of the Invention

[0004] This application provides an insulation detection and control method and system based on a high-voltage DC power supply system, which solves the technical problem of inaccurate fault location in the prior art.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] Firstly, an insulation detection and control method based on a high-voltage DC power supply system is provided, including:

[0007] The DC bus is divided into multiple zones, each containing a contactor;

[0008] Frequency sweep signals are injected between the positive bus and the ground wire, and between the negative bus and the ground wire, and the impedance response of each zone is collected;

[0009] The insulation degradation level of each zone is calculated based on the impedance response of each zone, and when the insulation degradation level is greater than a preset threshold, the pulse generator is activated to inject a synchronous traveling wave signal into the DC bus.

[0010] The time difference between the arrival of the traveling wave signal at the beginning and end of the DC bus is collected, and the distance between the fault point and the beginning of the DC bus is calculated based on the time difference to obtain the fault point location x.

[0011] If the fault location x is located in partition k∈(x k-1 ,x kIf the contactor of partition k is disconnected, then the contactor of partition k will be disconnected.

[0012] If the location of the fault point x = x k Then disconnect the contactor between partition k and partition k+1; where x k x0 represents the coordinates of the end of partition k, and x0 represents the beginning of the DC bus.

[0013] Based on the above technical solution, the insulation detection and control method for a high-voltage DC power supply system provided in this application divides the DC bus into multiple zones, which can reduce the fault range and improve detection efficiency. Injecting a sweep frequency signal between the positive and negative DC buses and the ground wire and collecting the impedance response of each zone node can comprehensively acquire the electrical characteristics of the system at different frequencies, providing rich data support for accurately assessing the insulation status. Based on the impedance response, the degree of insulation degradation in each zone is calculated. Combined with a preset threshold to activate a pulse generator to inject traveling waves, quantitative judgment of insulation defects and targeted fault location measures are achieved, improving the scientific rigor and reliability of the detection. Finally, the propagation characteristics of traveling waves are used to achieve precise fault location. Depending on the fault location, the zone contactor is selectively disconnected or a global power outage is executed. This minimizes the power outage area during local faults, ensuring normal operation of non-faulty areas, while ensuring system safety during severe faults, effectively balancing the system's reliability and safety requirements.

[0014] In conjunction with the first aspect above, in one possible implementation, voltage sensors and current sensors are deployed at the beginning and end of the DC bus of the high-voltage DC power supply system, and impedance monitoring units are set at each partition node to calculate the degree of insulation degradation of the partition.

[0015] In conjunction with the first aspect above, in one possible implementation, the calculation of the insulation degradation degree of each partition based on the impedance response of each partition includes:

[0016] The normalized frequency is obtained by calculating the ratio of the frequency of the swept frequency signal to the system reference frequency. ;

[0017] The frequency range of the swept frequency signal is calculated by comparing it with the system reference frequency, thus obtaining the integral frequency range. , ];

[0018] Based on the sweep frequency signal voltage of partition k and the collected response current The complex impedance of partition k is calculated. : ;

[0019] The system characteristic impedance Z0 is calculated based on the inductance L and capacitance C per unit length of the DC bus: ;

[0020] Based on the real part of the complex impedance of partition k and the virtual part Calculate the impedance phase angle : ;

[0021] Obtain the system's reference impedance. and reference phase angle The degree of insulation degradation in partition k is calculated using the formula. : ;in, Let λ represent the frequency weighting function, λ represent the high-frequency suppression coefficient, and β represent the phase difference sensitivity factor.

[0022] In conjunction with the first aspect above, in one possible implementation, the frequency weighting function The formula for calculation is: Where μ represents the normalized value of the system resonant frequency, and σ represents the bandwidth coefficient.

[0023] In conjunction with the first aspect above, in one possible implementation, the formula for calculating the distance x between the fault point and the beginning of the DC bus is: ;in, This represents the frequency-dependent wave velocity, used to characterize the propagation speed of traveling waves in dispersive media. denoted by , where α represents the frequency domain fault sensitivity factor, S represents the total length of the DC bus, and γ represents the nonlinear heterogeneity coefficient.

[0024] In conjunction with the first aspect above, in one possible implementation, the formula for calculating the frequency-dependent wave velocity is: Where v0 represents the reference wave velocity, C dist ω represents the dispersion distortion coefficient. n ω represents the target operating angular frequency. c denoted by ω, where ω represents the cutoff angular frequency of the medium, and s represents the dispersion slope index.

[0025] In conjunction with the first aspect above, in one possible implementation, the formula for calculating the frequency domain fault sensitivity factor is: ;in, Represents angular frequency. Indicates the frequency of target analysis. This represents the magnitude of the reflection coefficient at the fault location x. Indicates the damping factor. Let represent the imaginary part of the complex characteristic impedance of the transmission line, and let represent the complex characteristic impedance of the transmission line. The formula for calculation is: R represents resistance per unit length, L represents inductance per unit length, G represents conductance per unit length, C represents capacitance per unit length, and j represents the imaginary unit.

[0026] In conjunction with the first aspect above, in one possible implementation, the frequency sweep signal is an amplitude-adjustable sine wave, wherein the sine wave V inj The formula for calculating V is: inj =Asin(2πft); where the frequency range f∈[0.1,1000]Hz, the signal amplitude A is dynamically adjusted with the system voltage, and the adjustment calculation formula is: A=k a ×V dc k a ∈[0.01%, 0.1%], representing the adjustment coefficient, V dc This indicates the DC bus voltage.

[0027] In conjunction with the first aspect above, in one possible implementation, after obtaining the fault location, the fault type is determined based on the frequency domain fault sensitivity factor and the degree of insulation degradation:

[0028] If the frequency domain fault sensitivity factor is greater than the preset arc fault threshold, it is determined to be an arc fault.

[0029] If the proportion of the low-frequency component of the insulation degradation level is greater than a preset proportion threshold, it is determined to be a partition k insulation degradation fault; wherein, the proportion R of the low-frequency component of the insulation degradation level is... low The formula for calculation is: .

[0030] Secondly, an insulation detection and control device based on a high-voltage DC power supply system is provided, comprising: a communication unit and a processing unit;

[0031] The communication unit is used to communicate with the voltage sensor, current sensor and impedance monitoring unit of each partition node at the beginning and end of the DC bus, and to transmit sweep frequency signal injection command, traveling wave injection command and real-time acquired impedance response data and traveling wave arrival time difference data; at the same time, it sends a disconnect command to the partition contactor or a global power-off command to the system.

[0032] The processing unit is used to divide the DC bus into multiple partitions, generate a sweep frequency signal, and inject it between the positive and negative DC buses and the ground wire;

[0033] The insulation degradation level of each partition is calculated based on the impedance response of each partition, and when the insulation degradation level is greater than a preset threshold, the pulse generator is activated to inject a traveling wave.

[0034] The location of the fault point is calculated based on the time difference between the arrival of the traveling wave at the beginning and end of the DC bus, and the zone contactor is disconnected according to the location of the fault point.

[0035] Thirdly, this application provides an insulation detection and control device based on a high-voltage DC power supply system, comprising: a processor and a storage medium; the storage medium includes instructions, and the processor is used to execute the instructions to implement the method described in the first aspect and any possible implementation thereof. This insulation detection and control device based on a high-voltage DC power supply system can be an electronic device or a chip within an electronic device.

[0036] Fourthly, this application provides an insulation detection and control system based on a high-voltage DC power supply system, comprising: a partitioning module, a signal injection module, and a data processing module; wherein,

[0037] The partitioning module is used to divide the DC bus into multiple partitions; each partition is equipped with a contactor.

[0038] The signal injection module is used to inject sweep frequency signals between the positive bus and the ground wire, and between the negative bus and the ground wire; when the degree of insulation degradation is greater than a preset threshold, the pulse generator is activated to inject a synchronous traveling wave signal into the DC bus.

[0039] The data processing module is used to acquire the impedance response of each partition node when a frequency sweep signal is injected, and to calculate the degree of insulation degradation of each partition based on the impedance response of each partition; and,

[0040] When a synchronous traveling wave signal is injected, the time difference Δt between the traveling wave signal and the beginning and end of the DC bus is collected, and the distance between the fault point and the beginning of the DC bus is calculated based on the time difference to obtain the fault point location x.

[0041] Disconnect the zone contactor based on the location of the fault.

[0042] Fifthly, this application provides a computer-readable storage medium storing instructions that, when executed on an insulation detection and control device based on a high-voltage DC power supply system, cause the insulation detection and control device based on a high-voltage DC power supply system to perform the method described in the first aspect and any possible implementation thereof.

[0043] Sixthly, this application provides a computer program product containing instructions that, when the computer program product is run on an insulation detection and control device based on a high-voltage DC power supply system, cause the insulation detection and control device based on a high-voltage DC power supply system to perform the methods described in the first aspect and any possible implementation thereof.

[0044] This application provides an insulation detection and control device based on a high-voltage DC power supply system. By deploying voltage / current sensors at the beginning and end of the DC bus and setting impedance monitoring units at each zone node, it achieves accurate acquisition of the impedance response of each zone, providing reliable data support for calculating the degree of insulation degradation. Through normalized frequency processing, complex impedance and phase angle calculation, and the introduction of a characteristic impedance benchmark, combined with a Gaussian-distributed frequency weighting function and a phase difference sensitivity factor to construct an integral formula, the degree of insulation degradation can be comprehensively and accurately quantified, improving the accuracy of insulation condition assessment.

[0045] A fault location distance calculation formula constructed using parameters such as frequency-dependent wave velocity and frequency-domain fault sensitivity factor fully considers the propagation characteristics of traveling waves in dispersive media and the influence of the fault point reflection coefficient. This can improve fault location accuracy to the zone level and shorten fault investigation time. Simultaneously, the design of dynamically adjusting the sweep signal amplitude according to system voltage allows it to adapt to detection needs under different operating conditions, reducing detection errors caused by system voltage fluctuations. Through a joint judgment mechanism of frequency-domain fault sensitivity factor and the proportion of low-frequency components in insulation degradation, arc faults and insulation degradation faults can be accurately distinguished, providing a more detailed basis for operation and maintenance strategy formulation and improving the targeting and efficiency of system fault handling.

[0046] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A system architecture diagram of an insulation detection and control system based on a high-voltage DC power supply system is provided for embodiments of this application;

[0049] Figure 2 A schematic flowchart illustrating an insulation detection and control method based on a high-voltage DC power supply system, provided for an embodiment of this application;

[0050] Figure 3 A schematic flowchart of another insulation detection and control method based on a high-voltage DC power supply system provided in this application embodiment;

[0051] Figure 4 A schematic flowchart of another insulation detection and control method based on a high-voltage DC power supply system provided in this application embodiment;

[0052] Figure 5 A schematic diagram of an insulation detection and control device based on a high-voltage DC power supply system provided in this application embodiment;

[0053] Figure 6 This is a schematic diagram of the hardware structure of an insulation detection and control device based on a high-voltage DC power supply system, provided in an embodiment of this application. Detailed Implementation

[0054] In the description of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" means one or more, and "multiple" means two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0055] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0056] The insulation detection and control method based on a high-voltage DC power supply system provided in this application embodiment can be applied to, for example... Figure 1 In the insulation detection and control system based on a high-voltage DC power supply system shown, such as Figure 1 As shown, the communication system includes: a partitioning module, a signal injection module, and a data processing module.

[0057] The partitioning module is used to divide the DC bus into multiple partitions; each partition is equipped with a contactor.

[0058] The signal injection module is used to inject sweep frequency signals between the positive bus and the ground wire, and between the negative bus and the ground wire; when the insulation degradation level is greater than the preset threshold, the pulse generator is activated to inject a synchronous traveling wave signal into the DC bus.

[0059] The data processing module is used to acquire the impedance response of each partition node when a frequency sweep signal is injected, and to calculate the degree of insulation degradation of each partition based on the impedance response of each partition; and,

[0060] When a synchronous traveling wave signal is injected, the time difference Δt between the traveling wave signal and the beginning and end of the DC bus is collected, and the distance between the fault point and the beginning of the DC bus is calculated based on the time difference to obtain the fault point location x.

[0061] Disconnect the zone contactor based on the location of the fault.

[0062] To address the technical problems of low insulation detection accuracy and ambiguous fault location in existing high-voltage DC power supply systems, this application provides an insulation detection control method based on a high-voltage DC power supply system, which includes:

[0063] The DC bus is divided into multiple zones, each containing a contactor;

[0064] Frequency sweep signals are injected between the positive bus and the ground wire, and between the negative bus and the ground wire, and the impedance response of each zone is collected;

[0065] The insulation degradation level of each zone is calculated based on the impedance response of each zone, and when the insulation degradation level is greater than a preset threshold, the pulse generator is activated to inject a synchronous traveling wave signal into the DC bus.

[0066] The time difference between the arrival of the traveling wave signal at the beginning and end of the DC bus is collected, and the distance between the fault point and the beginning of the DC bus is calculated based on the time difference to obtain the location of the fault point.

[0067] Disconnect the contactor of the corresponding zone based on the location of the fault to achieve zone isolation.

[0068] Based on this, the present invention integrates partition detection and traveling wave positioning to construct a complete process from insulation condition assessment to precise fault isolation, which can improve the early warning capability and fault handling efficiency of insulation faults in high voltage DC systems, and provide refined technical support for the safe and stable operation of power systems.

[0069] like Figure 2 As shown in the figure, an insulation detection and control method based on a high-voltage DC power supply system provided in this application includes:

[0070] S1. Divide the DC bus into multiple zones, each containing a contactor.

[0071] Among them, the contactor is a switching element used to switch the DC bus partition circuit on and off. It can be controlled by electrical signals to achieve isolation and protection of the fault area.

[0072] In some implementations, zones can be divided based on the location of existing power distribution nodes, or based on the physical length of the busbar (e.g., dividing a zone into zones per kilometer) or the level of load importance (e.g., dividing critical load areas into separate zones).

[0073] It should be noted that the number of partitions should be matched with the system size to avoid increasing detection costs due to overly dense partitions, or affecting fault location accuracy due to overly sparse partitions.

[0074] For example: For a DC power supply system for urban rail transit, it can be divided into multiple zones according to the interval of the traction substation, and a contactor is installed at the beginning of each zone.

[0075] S2. Inject sweep frequency signals between the positive bus and the ground wire, and between the negative bus and the ground wire, and collect the impedance response of each partition.

[0076] Among them, the sweep frequency signal is an excitation signal with continuously changing frequency, used to excite the electrical response of the bus insulation medium; the impedance response refers to the characteristic of the change of the voltage-to-current ratio between the bus and the ground wire with frequency after the sweep frequency signal is injected.

[0077] In some implementations, a sweep frequency signal can be injected through a dedicated signal generator, and response data can be collected by the first and last sensors or the partition node monitoring unit and transmitted to the central processing unit.

[0078] It should be noted that the frequency range of the sweep signal must cover the characteristic frequency band of the insulation defect to avoid resonance interference with the system's inherent frequency.

[0079] For example, in a data center high-voltage DC system, a frequency sweep signal with a frequency ranging from low to medium can be injected, and the response can be collected by the impedance monitoring module built into each distribution cabinet.

[0080] S3. Calculate the insulation degradation level of each partition based on the impedance response of each partition, and when the insulation degradation level is greater than the preset threshold, activate the pulse generator to inject a synchronous traveling wave signal into the DC bus.

[0081] Among them, the degree of insulation degradation refers to the degree of aging or damage of the insulation material as quantified by the change in impedance response; the pulse generator is a device that generates high-voltage pulse signals to induce traveling wave propagation; the synchronous traveling wave signal is a pulse signal synchronized with the system clock, which facilitates the accurate measurement of the time difference between the beginning and end.

[0082] In some implementations, the degree of insulation degradation can be calculated by comparing the deviation of the current impedance response with the historical reference value, or by constructing an evaluation model based on impedance amplitude and phase changes.

[0083] It should be noted that the preset threshold needs to be dynamically adjusted based on factors such as the type of insulation material and the system's operating years to avoid misjudgment or missed detection.

[0084] For example, if the phase angle deviation of the impedance response of a certain partition exceeds 20% of the historical average and the amplitude deviation exceeds 15%, it can be determined that the insulation degradation exceeds the standard, triggering the pulse generator.

[0085] S4. Collect the time difference between the arrival of the traveling wave signal at the beginning and end of the DC bus, and calculate the distance between the fault point and the beginning of the DC bus based on the time difference to obtain the location of the fault point.

[0086] The time difference between the arrival of the traveling wave signal at the beginning and end of the DC bus is based on the idea of ​​traveling wave positioning: the traveling wave propagates in the bus at a fixed wave speed, and the time difference between the arrival of the traveling wave generated at the fault point and the beginning and end of the fault point is linearly related to the location of the fault point.

[0087] In some implementations, the traditional two-end traveling wave positioning method can be used, such as x = v × Δt / 2, where v is the wave velocity. Alternatively, the positioning algorithm can be optimized by incorporating factors such as busbar distribution parameters and load characteristics. For example, if the time difference between the arrival of the first and last ends of the traveling wave is 5 μs, and the wave velocity is assumed to be 2 × 10⁻⁶, then... 5 If the speed is km / s, then the distance from the fault point to the beginning is 500 meters.

[0088] S5. Disconnect the contactor of the corresponding zone according to the location of the fault to achieve zone isolation.

[0089] In some implementations, if the fault point is located within a certain partition, the contactor of that partition is disconnected; if the fault point is located at the boundary point of a partition, the contactor of the adjacent partition is disconnected.

[0090] It should be noted that the contactor disconnect command must have an anti-interference design to avoid accidental triggering that could cause power outages in non-faulty areas. At the same time, a backup protection strategy should be considered when the contactor fails to operate.

[0091] For example, when the fault is located in the middle of partition 3, the system automatically sends a command to disconnect the contactor of partition 3, while maintaining normal power supply to other partitions.

[0092] Based on the above technical solution, the insulation detection and control method provided in this application constructs a multi-level protection system from insulation condition assessment to precise fault isolation by combining zoned detection, frequency sweep excitation and traveling wave positioning. It can adapt to the insulation monitoring needs of high voltage DC systems of different scales. Compared with the traditional global detection scheme, it significantly improves the flexibility of fault handling and the reliability of system operation.

[0093] In one possible implementation of this application embodiment, the above-mentioned S1 can be specifically implemented by the following S101, S102 and S103, which are described in detail below:

[0094] S101. Determine the partitioning strategy based on the physical structure of the DC bus or the load distribution.

[0095] The zoning process needs to balance detection accuracy and engineering feasibility. Zoning boundaries can be determined based on bus length, branch node location, or load characteristics of the power supply area (such as important loads and non-important loads).

[0096] In some implementations, a physical zone can be divided every 500m or 1000m of busbar, or it can be naturally segmented according to the location of the power distribution switch cabinet. Alternatively, a high-load area can be divided into a separate zone based on the load current.

[0097] It should be noted that the number of partitions should not be too many (to avoid increased hardware costs) or too few (to avoid decreased positioning accuracy). Usually, it is advisable to control the number of partitions to 4-10 based on the system size, and the partition boundaries must ensure that the impedance monitoring unit can be deployed.

[0098] For example, a 3,000-meter-long DC power supply busbar for a subway is divided into four sections of 750 meters each, with each section covering the line segment between adjacent traction substations.

[0099] S102. Deploy voltage and current sensors at the beginning and end of the DC bus, and set up impedance monitoring units at each partition node.

[0100] Among them, the first and last sensors are used to collect the voltage / current response after the frequency sweep signal is injected, and the impedance monitoring unit of the partition node is used to monitor the impedance characteristics of each partition in real time, providing data support for insulation degradation calculation.

[0101] In some implementations, the voltage sensor uses a high-precision electronic voltage transformer, the current sensor uses a Rogowski coil (bandwidth covering 0.1Hz-100kHz), and the impedance monitoring unit is integrated into the partition control cabinet, supporting real-time uploading of frequency response data.

[0102] It should be noted that the sampling rate of the sensor and monitoring unit must be ≥10kHz to meet the high-frequency component acquisition requirements of the sweep frequency signal from 0.1 to 1000Hz, and the signal must be transmitted through shielded cables to reduce electromagnetic interference.

[0103] For example, in a high-voltage DC system of a data center, electronic voltage sensors with a rated voltage of 1500V are installed at the beginning and end, and impedance monitoring modules with DSP chips are deployed at each partition node to calculate the impedance value in the 10-1000Hz frequency band in real time.

[0104] S103. Each partition contains a DC contactor, and a logical correspondence is established between the contactor and the partition.

[0105] Among them, DC contactors are used to disconnect the corresponding zone circuit in case of a fault. The rated current of the contactor must be greater than the maximum operating current of the zone (e.g., 1.5 times the margin), and the breaking voltage must match the system voltage level. For example, a contactor with a rated voltage of 1200V should be selected for a 1000V DC system.

[0106] In some implementations, the contactor uses a permanent magnet DC contactor with fast breaking capability (breaking time ≤10ms) and is connected to the processing unit via hard wiring to ensure reliable command transmission.

[0107] It should be noted that the contactor needs to be linked with the impedance monitoring unit of the partition node. When the fault is located in partition k, the processing unit needs to send a trip command within 5ms, and the contactor needs to have an auxiliary contact feedback function to confirm the tripping status.

[0108] For example, in a 1500V DC system for urban rail transit, each zone is equipped with a permanent magnet DC contactor with a rated current of 3000A, a breaking voltage of 1800V, and a breaking time of 8ms. The auxiliary contacts transmit status signals to the central monitoring system via optical fiber.

[0109] Based on the above technical solution, the coordinated implementation of partitioning strategy design, sensor deployment and contactor installation lays the hardware foundation for subsequent frequency sweep signal injection, impedance response acquisition and fault partitioning isolation, ensuring the accuracy and reliability of insulation detection and fault location.

[0110] In one possible implementation of the embodiments of this application, combined with Figure 2 ,like Figure 3 As shown, the above S2 can be implemented through the following S201, S202 and S203, which are explained in detail below:

[0111] S201. Generate a sweep sine wave signal with adjustable amplitude.

[0112] The sweep frequency signal is a sinusoidal wave with a frequency continuously varying in the range of 0.1-1000Hz, and its amplitude A varies with the DC bus voltage V. dc Dynamic adjustment, the adjustment formula is A=k a ×V dc , where k a The adjustment factor is 0.01%-0.1%.

[0113] In some implementations, a fundamental signal can be generated using a digital signal generator (such as a DDS chip), amplified by a power amplifier, and then output. A voltage sensor can then monitor the voltage (V) in real time. dc And feed it back to the signal generator to dynamically adjust k. a To adapt to different working conditions.

[0114] It should be noted that the signal amplitude must be strictly limited within the system's safe range to avoid interference with the normal operation of the bus. For example, when V dc When the voltage is 1000V, the maximum value of A is 0.1×1000V=1V, ensuring that it does not exceed the busbar insulation withstand threshold.

[0115] For example, in a high-voltage DC power supply system, after the signal generator generates a sweep frequency signal, the amplitude is amplified to A = 0.05 × V by an operational amplifier. dc When V dc When the voltage is 800V, the output signal amplitude is 0.4V, and the frequency is scanned from 0.1Hz to 1000Hz in 10Hz steps.

[0116] S202. A sweep frequency signal is injected between the positive and negative DC bus and the ground wire through a coupling circuit.

[0117] The injection circuit must include a DC blocking capacitor and an impedance matching network to ensure that the sweep frequency signal is effectively coupled to the bus, while isolating the DC component to avoid affecting the normal power supply of the system.

[0118] In some implementations, high-voltage capacitors (such as film capacitors with a rated voltage of 2000V) are used as coupling elements, and the output impedance is adjusted through an LC matching network to match the characteristic impedance Z0 of the bus, thereby reducing signal reflection. The LC matching network is a circuit network composed of inductors (L, Inductor) and capacitors (C, Capacitor) used to adjust the impedance matching between circuits, thereby maximizing the power transmission efficiency between the signal source and the load.

[0119] It should be noted that the withstand voltage of the coupling circuit must be higher than the peak voltage of the DC bus, and the grounding loop must be reliably shielded to prevent electromagnetic interference from affecting signal quality.

[0120] For example, in a 1500V DC system, two 10μF / 2500V high-voltage capacitors are connected in series to the positive bus and the negative bus, respectively. A sweep frequency signal is injected between the bus and the ground through a π-type LC matching network (L=100μH, C=0.1μF). The impedance of the matching network is designed to be consistent with the characteristic impedance of the bus.

[0121] S203. Acquire impedance response using the first and last end sensors and the zone impedance monitoring unit.

[0122] Voltage and current sensors are deployed at both ends of the DC bus, and impedance monitoring units are set up at each partition node to collect the voltage after the frequency sweep signal is injected in real time. and response current Used to calculate partitioned complex impedance .

[0123] It should be noted that the sensor sampling rate must be ≥10kHz to meet the sampling requirements of the 1000Hz sweep frequency signal, and the clocks at both ends must be synchronized via GPS to ensure the phase accuracy of the impedance calculation.

[0124] Based on the above technical solution, by dynamically adjusting the parameters of the frequency sweep signal, designing the coupling circuit, and acquiring data collaboratively with multiple nodes, the comprehensive acquisition of the bus impedance characteristics at different frequencies was achieved. This provides high-precision electrical response data for subsequent insulation degradation calculations, ensuring the accuracy and reliability of insulation condition assessment.

[0125] In one possible implementation of this application embodiment, the above-mentioned S3 can be specifically implemented by the following S301, S302 and S303, which are described in detail below:

[0126] S301. Calculate the normalized frequency and the range of the integral frequency.

[0127] Specifically: the normalized frequency is obtained by calculating the ratio of the actual frequency of the swept frequency signal to the system reference frequency. Then, the actual frequency range is compared with the system reference frequency to determine the integral frequency range. , This process is used to eliminate the influence of frequency differences between different systems and to unify the calculation benchmark.

[0128] In some implementations, the reference frequency can be selected from the system's rated frequency, such as 50Hz. The actual frequency range is determined based on the frequency scanning range (0.1-1000Hz) of the sweep signal, and the normalized integration interval is obtained through linear mapping. For example, when the set frequency range is 0.1-1000Hz, the corresponding normalized frequency range is [0.1 / 50, 1000 / 50] = [0.002, 20].

[0129] It should be noted that the integration frequency range must cover the characteristic frequency band of the insulation defect to avoid deviations in the calculation of the degree of degradation due to improper selection of the frequency band. For example, insulation degradation faults often manifest as changes in low-frequency characteristics, so it is necessary to ensure that the low-frequency band (such as 0.110Hz) is within the integration range.

[0130] S302. Calculate the complex impedance, characteristic impedance, and phase angle of the partition.

[0131] Among them, the partitioned complex impedance refers to the frequency domain ratio of the voltage and current between the DC bus and the ground wire in partition k after the injection of the sweep frequency signal. It is essentially a complex number containing a real part (resistance component) and a 2 imaginary part (reactance component), and its unit is ohms.

[0132] Characteristic impedance is an inherent electrical parameter of a DC bus, determined by the inductance and capacitance per unit length of the bus. Its value is only related to the physical structure and material properties of the bus and is independent of frequency.

[0133] The phase angle is a phase property of complex impedance, reflecting the phase difference between voltage and current. It is calculated using the real and imaginary parts of the complex impedance and is expressed in radians (rad) or degrees (°).

[0134] (1) Calculate the complex impedance: based on the sweep frequency signal voltage of partition k and response current Calculate complex impedance ;

[0135] (2) Calculate the characteristic impedance: Calculate the characteristic impedance based on the inductance L and capacitance C per unit length of the DC bus. ;

[0136] (3) Calculate the phase angle: Calculate the phase angle using the real and imaginary parts of the complex impedance. .

[0137] In some implementations, voltage and current signals are converted to the frequency domain via FFT (Fast Fourier Transform), and the complex impedance at each frequency point is calculated in real time using a sliding window algorithm; the inductance L and capacitance C per unit length can be obtained through bus physical parameters (such as conductor cross-sectional area and insulation layer thickness) or through on-site measurement.

[0138] It should be noted that noise interference must be considered when calculating complex impedance. Kalman filtering and other algorithms can be used to denoise the sampled data. The characteristic impedance Z0 needs to be dynamically updated according to the actual distribution parameters of the bus to avoid calculation errors caused by parameter deviations.

[0139] For example, a frequency sweep signal with a frequency of f=100Hz is injected into a certain partition. At this time, the voltage V=0.5V and the current I=0.01A of partition k are as follows: The complex impedance Z k =50Ω; if the inductance per unit length of the busbar is L=0.5μH / m and the capacitance is C=0.1nF / m, then the characteristic impedance is... Phase angle =0° indicates that the impedance characteristic of this partition is purely resistive, with no phase shift caused by inductance or capacitance.

[0140] S303. Calculate the degree of insulation degradation and determine whether to activate the pulse generator.

[0141] The formula for calculating the degree of insulation degradation is: Calculate the degree of insulation degradation ,in, Indicates the reference impedance. Indicates the reference phase angle. The frequency weighting function (Gaussian distribution) uses λ as the high-frequency suppression coefficient (ranging from 0.1 to 0.5, adjustable based on high-frequency interference in the system) and β as the phase difference sensitivity factor (ranging from 0.5 to 1.5). When... When the preset threshold is exceeded, the pulse generator is activated to inject a synchronous traveling wave signal.

[0142] It should be noted that the reference impedance reference refers to the complex impedance reference value at each frequency point when the DC bus is in good insulation condition, i.e., when the system is fault-free, and is used to characterize the impedance characteristics of the system during normal operation; the reference phase angle refers to the phase difference reference value between voltage and current at each frequency point when the DC bus is in good insulation condition (i.e., when the system is fault-free), and is used to characterize the phase characteristics of the system during normal operation.

[0143] In some implementations, the reference impedance and reference phase angle can be obtained by calibrating the impedance response data of the newly commissioned system; the preset threshold is determined by accelerated aging tests or historical operating data. For example, if the calculated threshold for a certain partition... =0.8, the preset threshold is 0.5, then the pulse generator is activated to inject a synchronous traveling wave signal into the bus. The traveling wave signal is synchronized with the system clock, and the acquisition accuracy of the time difference between the beginning and end must be within 1μs.

[0144] Among them, the frequency weighting function The formula for calculation is: Where μ represents the normalized value of the system resonant frequency, and σ represents the bandwidth coefficient. Furthermore, μ and σ can be adjusted according to the characteristic frequency of the insulating material. For example, if the characteristic frequency of oil-paper insulation is concentrated in the 10-100Hz range, μ can be set to 2 and σ to 1.

[0145] Based on the above technical solution, by normalizing the frequency, calculating multiple parameters of complex impedance and phase angle, and combining an integral model constructed with a frequency weighting function and a phase difference factor, the degree of insulation degradation is accurately quantified. This process fully considers the joint changes in impedance amplitude and phase, better reflects the aging state of the insulation material, and improves the accuracy and reliability of fault early warning.

[0146] In one possible implementation of the embodiments of this application, combined with Figure 2 ,like Figure 4 As shown, the above S4 specifically includes the following S401 to S403:

[0147] S401. Acquire the time difference Δt between the arrival time of the traveling wave signal at the beginning and end of the DC bus.

[0148] Specifically, voltage / current sensors (such as Hall effect sensors or Rogowski coils) deployed at the beginning and end of the DC bus are used to acquire traveling wave signals in real time. The time difference Δt is calculated by comparing the arrival times of the traveling wave at the beginning and end. This time difference is used as the basis for subsequent calculations of the distance to the fault point.

[0149] S402. Calculate the frequency-dependent wave velocity v(ωn) and the frequency domain fault sensitivity factor Λ(ωn).

[0150] Specifically, the frequency-dependent wave velocity is determined according to the formula... Calculate, where v0 is the reference wave speed (e.g., 0.7 times the speed of light in a vacuum), C dist ω represents the dispersion distortion coefficient (ranging from 0.1 to 0.5, calibrated through frequency domain response testing). n ω is the target angular frequency. c ω is the cutoff angular frequency of the medium, and s is the dispersion slope exponent (ranging from 1 to 3, determined by frequency domain response testing, reflecting how fast the dispersion changes with frequency).

[0151] Frequency domain fault sensitivity factor is obtained through integral formula ,in The complex characteristic impedance of the transmission line. δ is the magnitude of the reflection coefficient at the fault point, and δ is the damping factor (ranging from 0.1 to 1.0, determined by the integral convergence test of the frequency domain fault sensitivity factor).

[0152] In some implementations, bus parameters (such as L, C, R, G) are obtained through on-site measurements or design documents. dist The frequency response and s are calibrated through frequency domain response testing; the integral calculation adopts numerical methods (such as Gaussian integral) and uses FFT to accelerate frequency domain transformation.

[0153] For example, if v0 = 2 × 10 5 km / s, C dist =0.1, ω n =2π×1000rad / s, ω c =2π×500rad / s, s=2, then .

[0154] S403. Calculate the fault location x based on the time difference and wave velocity.

[0155] Where: according to the formula Calculate the distance between the fault point and the head end, where α is the weight adjustment coefficient (default value is 0.5) in rad / (Ω·s), S is the total length of the busbar, and γ is the nonlinear heterogeneity coefficient (default value is 1). The degree of insulation degradation in partition k.

[0156] In some implementations: when the degree of insulation degradation When smaller (e.g., | (|<0.5), the latter term can be ignored, simplifying to the traditional two-terminal method. When the fault is severe, the subsequent term corrects the location result by using frequency domain sensitivity factors and the degree of degradation.

[0157] It should be noted that the weighting coefficient α needs to be adjusted according to the system size (e.g., 0.8 for long busbars and 0.5 for short busbars) to avoid the latter term from excessively affecting the positioning accuracy; the measurement error of S needs to be controlled within ±1%, otherwise it will accumulate in the calculation of x.

[0158] Example: Total busbar length S = 2km, =2.12×10 5 km / s, Δt=10μs =0.6, α=0.7, =0.8, γ=1, then x=(2.12×10 5 ×10×10 -6 ) / 2+0.7×0.6×2×0.8 / (1+1×0.8)=1.06+0.373=1.433km. That is, the fault location is 1.433km from the beginning of the bus.

[0159] Based on the above technical solution, by introducing frequency-dependent wave velocity and frequency-domain fault sensitivity factors, the propagation characteristics of traveling waves in dispersive media and the influence of the reflection coefficient at the fault point are fully considered, thereby improving the positioning accuracy of the traditional two-end traveling wave location method and shortening the fault diagnosis time. This method adapts to different fault severity levels through dynamic correction terms, improving the algorithm's adaptability to complex working conditions while ensuring positioning accuracy.

[0160] In one possible implementation of this application embodiment, step S5 may specifically include:

[0161] S501. Determine the relationship between the fault location x and the partition coordinates.

[0162] Wherein: the coordinate range of each partition is preset to be k∈(x k-1 ,x k ), where x0 is the coordinate of the beginning of the DC bus, x k Let x be the coordinates of the end point of partition k. By comparing the relationship between the fault location x and the coordinates of each partition, the fault location area can be determined.

[0163] In some implementations, if k∈(x k-1 ,x k If x = x, then the fault point is determined to be located within partition k; if x = x k(i.e., the fault point is located at the node between partition k and k + 1), it is determined as a cross - partition fault; if x exceeds the coordinate range of all partitions (such as x < x0 or x > x n , where n is the total number of partitions), it is determined as a global fault.

[0164] S502. Perform partition isolation or global power - off according to the fault - point location.

[0165] Among them, if the fault point is within partition k, that is, x ∈ (x k-1 , x k ), a trip command is sent to the contactor of partition k to disconnect the circuit of this partition;

[0166] If the fault point is at the partition - node coordinate x = x k , the contactors of both partition k and partition k + 1 are disconnected simultaneously;

[0167] If the fault point exceeds all partition ranges or the positioning fails (such as the time - difference acquisition error exceeds the threshold), global power - off is performed to cut off all contactors of the DC bus.

[0168] In some implementation manners, the contactor trip command is transmitted through hard - wiring, the response time ≤ 10 ms, and the trip state is fed back to the processing unit through auxiliary contacts. The global power - off command needs to trigger the trip coils of all partition contactors simultaneously and ensure reliability through a redundant circuit.

[0169] It should be noted that global power - off is only performed when the fault point cannot be located or a cross - partition fault occurs, and it needs to cooperate with the system protection device (such as over - current protection) to avoid misoperation resulting in a power outage of the entire system.

[0170] Exemplarily, when the fault point is located at 1200 m and the coordinate range of partition 3 is (1000 m, 1500 m), the contactor of partition 3 is disconnected; if x = 1500 m (the common node of partition 3 and partition 4), the contactors of both partition 3 and partition 4 are disconnected simultaneously.

[0171] S503. Verify the partition - isolation effect and record the fault data.

[0172] After disconnecting the contactor, bus voltage and current signals are collected by the head - end and end - point sensors and the partition impedance monitoring unit to verify whether the fault is isolated. If the isolation is successful (no voltage / current response in the partition where the fault point is located), the fault time, location, and insulation deterioration degree are recorded; if the isolation fails (such as the contactor refuses to operate), a backup protection strategy (such as a secondary trip command or starting a circuit breaker) is activated.

[0173] In some implementations, the verification process involves real-time calculation of the complex impedance of each partition. If the complex impedance of partition k approaches infinity (open circuit state), the isolation is considered successful. Fault data is stored in the system database for subsequent fault analysis and insulation condition trend assessment.

[0174] For example, after disconnecting the contactor of zone 2, the complex impedance of zone 2 was monitored and increased from 50Ω to over 1000Ω, which was determined to be a successful isolation. The fault time was recorded as 14:30 on June 19, 2025, and the insulation degradation degree Δξ=0.8.

[0175] S504. Execute subsequent maintenance strategies based on fault type.

[0176] Specifically, this is achieved through the frequency domain fault sensitivity factor Λ and the proportion of low-frequency components in insulation degradation R. low Determine the type of fault:

[0177] like If the arc fault threshold (e.g., 0.5) is used to determine an arc fault, it is necessary to check bus joints, contactor contacts and other parts that are prone to arcing.

[0178] If R low If a preset percentage threshold (e.g., 90%) is used, it is determined to be an insulation degradation fault, and the bus insulation layer of section k needs to be subjected to aging testing (e.g., dielectric loss testing).

[0179] In some implementations, the arc fault threshold is determined through accelerated aging experiments; for example, if the average value of Λ during simulated contact arcing is 0.6, the threshold is set to 0.5; R low The calculation is based on the integral formula. When the integral value of the low-frequency band (0.1-10Hz) exceeds 90%, it indicates that the molecular structure of the insulating material has deteriorated.

[0180] It should be noted that fault type determination should be carried out after zone isolation to avoid the risk of live testing; for insulation degradation faults, the degree of insulation deterioration should be retested regularly, and if Δξ continues to rise, bus insulation repair or replacement should be arranged.

[0181] For example, in a certain fault, Λ=0.7>0.5, which is determined to be an arc fault. Inspection revealed burn marks on the contactor contacts in zone 3, requiring replacement of the contactor; in another fault, R... low =92%>90%, which is judged as insulation degradation. Dielectric loss test was performed on the busbar of section 2. It was found that the dielectric loss tangent value increased by 50% compared with the reference value, and insulation layer repair needs to be arranged.

[0182] Based on the above technical solutions, by accurately matching the fault location with the partition coordinates, and by the differentiated design of the contactor tripping logic, combined with the in-depth judgment of the fault type, not only is the safe isolation of the system in case of faults ensured, but also the fault data recording and type analysis provide a basis for preventive maintenance, thereby improving the operation and maintenance efficiency and reliability of the high-voltage DC power supply system.

[0183] The above primarily describes the solutions of the embodiments of this application from the perspective of device implementation. It is understood that each device, such as an insulation detection and control device based on a high-voltage DC power supply system, includes at least one of the hardware structures and software modules corresponding to each function in order to achieve the above-mentioned functions. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0184] This application embodiment can divide the insulation detection and control device based on the high-voltage DC power supply system into functional units according to the above method example. For example, each function can be divided into a separate functional unit, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or software. It should be noted that the unit division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0185] When using integrated units, Figure 5 The above-described embodiment shows a possible structural schematic diagram of an insulation detection and control device based on a high-voltage DC power supply system (referred to as insulation detection and control device 50 based on a high-voltage DC power supply system). The insulation detection and control device 50 based on a high-voltage DC power supply system includes a processing unit 501 and a communication unit 502, and may also include a storage unit 503. Figure 5 The schematic diagram shown can be used to illustrate the structure of the insulation detection and control device based on the high-voltage DC power supply system involved in the above embodiments.

[0186] when Figure 5The schematic diagram shown illustrates the structure of the insulation detection and control device based on a high-voltage DC power supply system involved in the above embodiments. The processing unit 501 is used to control and manage the operation of the insulation detection and control device based on a high-voltage DC power supply system. The communication unit 502 is used for the insulation detection and control device based on a high-voltage DC power supply system to communicate with other devices. The storage unit 503 is used to store the program code and data of the insulation detection and control device based on a high-voltage DC power supply system.

[0187] For example, the communication unit 502 is used to communicate with the voltage sensor, current sensor and impedance monitoring unit of each partition node at the beginning and end of the DC bus, transmit sweep frequency signal injection command and traveling wave injection command, and collect impedance response data and traveling wave arrival time difference data in real time; at the same time, it sends a disconnect command to the partition contactor or a global power-off command to the system.

[0188] The processing unit 501 is used to divide the DC bus into multiple zones, generate an amplitude-adjustable sweep frequency sine wave signal and inject it between the positive and negative DC bus and the ground wire; calculate the degree of insulation degradation based on the impedance response of each zone, and activate the pulse generator to inject a traveling wave when the degree of degradation is greater than a preset threshold; calculate the location of the fault point based on the time difference of the traveling wave, and disconnect the contactor of the corresponding zone according to the location.

[0189] In one possible implementation, the processing unit 501 is also used to perform normalized frequency calculation, complex impedance and phase angle calculation, quantify the degree of insulation degradation through an integral formula, wherein the frequency weighting function is calculated in the form of a Gaussian distribution, and a phase difference sensitivity factor is introduced to improve the evaluation accuracy.

[0190] In one possible implementation, the communication unit 502 is also used to receive the synchronization signal feedback from the pulse generator and the contactor tripping status signal, and the processing unit 501 is also used to determine the fault type (such as arc fault or insulation degradation fault) based on the frequency domain fault sensitivity factor and the proportion of low-frequency components of insulation degradation degree, and generate corresponding operation and maintenance strategy instructions.

[0191] The processing unit 501 can be a processor or a controller, and the communication unit 502 can be a communication interface, transceiver, transceiver circuit, transceiver device, etc. The term "communication interface" is a general term and may include one or more interfaces. The storage unit 503 can be a memory. When the insulation detection and control device 50 based on the high-voltage DC power supply system is a chip, the processing unit 501 can be a processor or a controller, and the communication unit 502 can be an input interface and / or an output interface, pins, or circuits, etc. The storage unit 503 can be a storage unit within the chip (e.g., a register, cache, etc.) or a storage unit located outside the chip (e.g., read-only memory (ROM), random access memory (RAM, etc.).

[0192] The communication unit can also be called a transceiver unit. The antenna and control circuit with transceiver functions in the insulation detection and control device 50 based on the high-voltage DC power supply system can be considered as the communication unit 502 of the insulation detection and control device 50 based on the high-voltage DC power supply system, and the processor with processing functions can be considered as the processing unit 501 of the insulation detection and control device 50 based on the high-voltage DC power supply system. Optionally, the device in the communication unit 502 used to implement the receiving function can be considered as a communication unit, which is used to execute the receiving steps in the embodiments of this application. The communication unit can be a receiver, a receiver circuit, etc. The device in the communication unit 502 used to implement the transmitting function can be considered as a transmitting unit, which is used to execute the transmitting steps in the embodiments of this application. The transmitting unit can be a transmitter, a transmitter, a transmitting circuit, etc.

[0193] Figure 5 If the integrated units in the process are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. Storage media for storing computer software products include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0194] Figure 5 The units in the process can also be called modules; for example, a processing unit can be called a processing module.

[0195] This application also provides a hardware structure diagram of an insulation detection and control device based on a high-voltage DC power supply system (denoted as insulation detection and control device 60 based on a high-voltage DC power supply system), see [link to relevant documentation]. Figure 6 The insulation detection and control device 60 based on a high-voltage DC power supply system includes a processor 601, and optionally, a memory 602 connected to the processor 601.

[0196] In the first possible implementation, see Figure 6 The insulation detection and control device 60 based on a high-voltage DC power supply system also includes a transceiver 603. The processor 601, memory 602, and transceiver 603 are connected via a bus. The transceiver 603 is used to communicate with other devices or communication networks. Optionally, the transceiver 603 may include a transmitter and a receiver. The device in the transceiver 603 that implements the receiving function can be considered as a receiver, which is used to perform the receiving steps in the embodiments of this application. The device in the transceiver 603 that implements the transmitting function can be considered as a transmitter, which is used to perform the transmitting steps in the embodiments of this application.

[0197] Based on the first possible implementation method Figure 6 The schematic diagram shown can be used to illustrate the structure of the insulation detection and control device based on the high-voltage DC power supply system involved in the above embodiments.

[0198] in, Figure 6 The diagram can also illustrate the system chip in an insulation detection and control device based on a high-voltage DC power supply system. In this case, the actions performed by the aforementioned insulation detection and control device based on a high-voltage DC power supply system can be implemented by this system chip. The specific actions performed can be found above and will not be repeated here.

[0199] In implementation, each step of the method provided in this embodiment can be completed by integrated logic circuits in the processor or by instructions in software form. The steps of the method disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules in the processor.

[0200] The processor in this application may include, but is not limited to, at least one of the following: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, etc., which are various computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing. The processor may be a separate semiconductor chip or integrated with other circuits into a single semiconductor chip. For example, it may be integrated with other circuits (such as encoding / decoding circuits, hardware acceleration circuits, or various bus and interface circuits) to form a SoC (System-on-a-Chip), or it may be integrated as a built-in processor within an ASIC. The ASIC with the integrated processor may be packaged separately or together with other circuits. In addition to the cores for executing software instructions to perform calculations or processing, the processor may further include necessary hardware accelerators, such as field-programmable gate arrays (FPGAs), PLDs (programmable logic devices), or logic circuits that implement dedicated logic operations.

[0201] The memory in the embodiments of this application may include at least one of the following types: read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions; random access memory (RAM) or other types of dynamic storage devices capable of storing information and instructions; or electrically erasable programmable-only memory (EEPROM). In some scenarios, the memory may also be a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer, but is not limited thereto.

[0202] This application also provides a computer-readable storage medium including instructions that, when run on a computer, cause the computer to perform any of the methods described above.

[0203] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to perform any of the methods described above.

[0204] This application also provides a chip including a processor and an interface circuit. The interface circuit is coupled to the processor. The processor is used to run computer programs or instructions to implement the above-described method. The interface circuit is used to communicate with other modules outside the chip.

[0205] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0206] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0207] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and variations.

Claims

1. A method for insulation detection control based on a high voltage direct current power supply system, characterized by, The application relates to a method for detecting insulation fault of a DC bus, comprising the following steps: The DC bus is divided into multiple partitions, each of which contains a contactor; the DC bus comprises a positive bus and a negative bus; Sweep signals are injected between the positive bus and the ground and between the negative bus and the ground, and the impedance responses of the partitions are collected; The insulation deterioration degree of each partition is calculated based on the impedance responses of the partitions; When the insulation deterioration degree is greater than a preset threshold, a pulse generator is activated to inject a synchronous traveling wave signal into the DC bus, and the time difference of the arrival of the synchronous traveling wave signal at the first end and the last end of the DC bus is collected; The distance between the fault point and the first end of the DC bus is calculated based on the time difference, and the fault point position x is obtained; if the fault point position x is located in the partition k e (x k-1 ,x k ), then disconnect the contactor of the partition k; If the fault point position x = x k , then disconnect the contactors of the partition k and the partition k+1; wherein x k represents the end coordinate of the partition k, and x0 represents the head end of the DC bus. The insulation deterioration degree of each partition is calculated based on the impedance responses of the partitions, comprising the following steps: dividing the frequency of the swept signal by a system reference frequency to obtain a normalized frequency ; The frequency range of the sweep signal is calculated by ratio with the system reference frequency to obtain the integral frequency range , ]. Based on the swept frequency signal at the normalized frequency and the response current of the partition k, the complex impedance of the partition k is calculated and the impedance phase angle of the partition k ; The system characteristic impedance Z0 is calculated according to the unit length inductance and the unit length capacitance of the DC bus; Obtaining a reference impedance reference for a system and a reference phase angle and combining the complex impedance of the partition k the impedance phase angle of the partition k and the system characteristic impedance Z0 to calculate the degree of insulation deterioration.

2. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 1, characterized by, The insulation deterioration degree calculation formula is: ; wherein, represents a frequency weight function, λ represents a high frequency suppression coefficient, and β represents a phase difference sensitivity factor, represents an insulation deterioration degree is a function related to a normalized frequency .

3. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 2, characterized by, The frequency weight function The calculation formula is: ; wherein, μ represents a system resonance frequency normalized value, and σ represents a bandwidth coefficient.

4. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 2, characterized by, The calculation formula of the distance x of the fault point from the first end of the DC bus is: ; wherein, represents the frequency-dependent wave speed, used to characterize the propagation speed of the traveling wave in the dispersive medium, represents the frequency-domain fault sensitivity factor, a represents the weight adjustment coefficient, S represents the total length of the DC bus, γ represents the nonlinear heterogeneous coefficient, and Δt represents the time difference between the arrival of the traveling wave signals at the first and last ends of the DC bus.

5. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 4, characterized by, The formula for calculating the frequency-dependent wave velocity is: ; where v0represents a reference wave velocity, C dist represents a dispersion distortion coefficient, ω n represents a target operating angular frequency, ω c represents a medium cutoff angular frequency, s represents a dispersion slope exponent.

6. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 4, characterized by, The calculation formula of the frequency domain fault sensitive factor is: ; wherein, represents an angular frequency, represents a target analysis frequency, represents a reflection coefficient modulus value at a fault position x, represents a damping factor, represents an imaginary part of a complex characteristic impedance of a transmission line, and the complex characteristic impedance of the transmission line is calculated as: , R represents a unit length resistance, L represents a unit length inductance, G represents a unit length conductance, C represents a unit length capacitance, and j represents an imaginary unit.

7. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 1, characterized by, The sweep signal is a sine wave voltage with adjustable amplitude, and the sine wave voltage V inj The calculation formula is: V inj (f)=Asin(2πft); wherein, the frequency range f∈[0.1, 1000] Hz, A represents the amplitude of the voltage signal, and t represents time.

8. The insulation detection control method based on a high-voltage direct-current power supply system according to claim 2, characterized by, After the fault point position is obtained, the fault type is judged according to the frequency domain fault sensitive factor and the insulation deterioration degree: If the frequency domain fault sensitive factor is greater than a preset arc fault threshold, the arc fault is determined; If the low-frequency component proportion of the insulation deterioration degree is greater than a preset proportion threshold, it is determined that the partition k insulation degradation fault; wherein the low-frequency component proportion R of the insulation deterioration degree low The calculation formula is: .

9. An insulation detection control system based on a high voltage direct current power supply system, characterized by The application relates to a method for detecting insulation fault of a DC bus, comprising the following steps: The partition module, the signal injection module and the data processing module; wherein, The partition module is used for dividing the DC bus into multiple partitions; wherein, each partition is provided with a contactor; The signal injection module is used for injecting sweep signals between the positive bus and the ground and between the negative bus and the ground; when the insulation deterioration degree is greater than a preset threshold, a pulse generator is activated to inject a synchronous traveling wave signal into the DC bus; The data processing module is used for collecting the impedance responses of the partition nodes when the sweep signals are injected, and calculating the insulation deterioration degree of each partition based on the impedance responses of the partitions; and, When the synchronous traveling wave signal is injected, the time difference of the arrival of the traveling wave signal at the first end and the last end of the DC bus is collected, and the distance between the fault point and the first end of the DC bus is calculated based on the time difference, so that the fault point position is obtained; The partition contactor is disconnected according to the fault point position; The insulation deterioration degree of each partition is calculated based on the impedance responses of the partitions, comprising the following steps: dividing the frequency of the swept signal by a system reference frequency to obtain a normalized frequency ; The frequency range of the sweep signal is calculated by ratio with the system reference frequency to obtain the integral frequency range , ]. Based on the frequency-swept signal at the normalized frequency and the response current of the partition k, the complex impedance of the partition k is calculated and the impedance phase angle of the partition k ; The system characteristic impedance Z0 is calculated according to the unit length inductance and the unit length capacitance of the DC bus; Reference impedance reference of acquisition system and reference phase angle and combining the complex impedance of the partition k the impedance phase angle of the partition k and the system characteristic impedance Z0 , representing the insulation deterioration degree is a function of the normalized frequency .

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