Cable partial discharge monitoring method, device and system

Abstract

The application provides a cable partial discharge monitoring method, device and system, and belongs to the technical field of electric power. The cable partial discharge monitoring method comprises the following steps: obtaining a voltage phase reference source, wherein the voltage phase reference source is a standard alternating voltage signal of a transformer substation; obtaining a partial discharge signal of a cable; determining a phase position in the partial discharge signal of the cable based on a voltage zero-crossing point of the voltage phase reference source; generating a graph based on the partial discharge signal of the cable and the phase position, wherein the graph comprises a phase-resolved partial discharge graph and / or a phase-resolved pulse sequence graph; and obtaining a cable partial discharge monitoring result based on the graph. The load factor interference problem existing in the current phase reference is fundamentally avoided, the graph statistical characteristics (discharge amount and phase distribution) can truly reflect the insulation defect characteristics, and the cable partial discharge monitoring accuracy is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power, in particular to a cable partial discharge monitoring method, a cable partial discharge monitoring system, a cable partial discharge monitoring device, a machine readable storage medium and an electronic device. BACKGROUND

[0002] In the power construction of megacities, power pipe corridors are widely used in urban power grids due to their small occupation and avoidance of the impact of overhead lines on urban landscapes. However, the environment of the pipe corridor is relatively complex, and the insulation of the cables running in the pipe corridor, especially at the cable joint position, may be deteriorated due to the influence of electricity, heat, mechanical stress and environmental factors, which is the main cause of urban power failure. Partial discharge monitoring as an effective means to evaluate the insulation state of the cable is of great significance for early warning and avoiding equipment failure.

[0003] Please refer to Figure 2 , Figure 2 The system architecture and workflow diagram of the prior art are schematically shown. Traditional cable partial discharge monitoring mainly relies on the Rogowski coil to capture the power frequency current as a phase reference to generate the phase-resolved partial discharge (PRPD) spectrum and the phase-resolved pulse sequence (PRPS) spectrum. However, the Rogowski coil is easily affected by power grid harmonic disturbance, and the additional phase shift introduced by the sheath circulating current makes the phase signal output by the Rogowski coil unstable or distorted. The cable line can be converted into a load formed by inductance (L) / capacitance (C), and the actual current phase angle of the line will deviate from the reference voltage phase. The Rogowski coil can only measure the actual current phase of the line, and the coil has an angle difference caused by the magnetic flux lag due to the excitation branch iron loss / copper loss. Finally, the reference phase relied on to generate the PRPD spectrum is distorted, and the Rogowski coil is easily saturated in a large current and strong electromagnetic environment, resulting in distorted output waveform. These factors make the PRPD / PRPS spectrum based on the current phase distorted and unable to truly reflect the characteristics of the partial discharge, making the cable partial discharge monitoring not accurate enough. SUMMARY

[0004] The embodiment of the present application aims to provide a cable partial discharge monitoring method, a cable partial discharge monitoring system, a cable partial discharge monitoring device, a machine readable storage medium and an electronic device, which directly uses the standard AC voltage signal of a substation as a global phase reference, ensures that the graphs of each monitoring point are strictly aligned to the real system voltage zero point phase, can make the graph statistical characteristics (discharge amount, phase distribution) truly reflect the insulation defect characteristics, solves the graph distortion problem, and greatly improves the cable partial discharge monitoring accuracy.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a cable partial discharge monitoring method applied to each cable joint monitoring point, which comprises:

[0006] obtaining a voltage phase reference source, which is a standard AC voltage signal of a substation;

[0007] obtaining a partial discharge signal of a cable;

[0008] determining a phase position in the partial discharge signal of the cable based on the voltage zero point of the voltage phase reference source;

[0009] generating a graph based on the partial discharge signal of the cable and the phase position, wherein the graph comprises a phase-resolved partial discharge graph and / or a phase-resolved pulse sequence graph;

[0010] obtaining a cable partial discharge monitoring result based on the graph.

[0011] In the embodiment of the present application, the voltage phase reference source is obtained by:

[0012] obtaining an optical carrier phase signal through an optical fiber, which is obtained by converting the standard AC voltage signal of the substation into an optical signal;

[0013] obtaining the voltage phase reference source based on the optical carrier phase signal.

[0014] In the embodiment of the present application, the optical carrier phase signal is obtained through an optical fiber by:

[0015] obtaining the ambient temperature information and the length of the optical fiber;

[0016] calculating a compensation delay amount based on the ambient temperature information and the length of the optical fiber;

[0017] obtaining the optical carrier phase signal through the optical fiber, and adjusting the emission timing of the signal sending end of the optical fiber based on the compensation delay amount.

[0018] In the embodiment of the present application, the compensation time delay is calculated based on the ambient temperature information and the length of the optical fiber, and the compensation time delay comprises:

[0019] The static transmission time delay is calculated based on the length of the optical fiber.

[0020] The temperature drift time delay is calculated based on the ambient temperature information and the length of the optical fiber.

[0021] The compensation time delay is obtained based on the static transmission time delay and the temperature drift time delay.

[0022] In the embodiment of the present application, the static transmission time delay is calculated based on the length of the optical fiber, and the static transmission time delay comprises:

[0023] The length of the optical fiber is substituted into a preset first time delay calculation formula to obtain the static transmission time delay, and the preset first time delay calculation formula is:

[0024] ,

[0025] wherein, is the group refractive index of the optical fiber, is the length of the optical fiber, is the vacuum light speed, is the static transmission time delay.

[0026] In the embodiment of the present application, the temperature drift time delay is calculated based on the ambient temperature information and the length of the optical fiber, and the temperature drift time delay comprises:

[0027] The reference temperature variation is calculated based on the ambient temperature information and a preset reference temperature of the optical fiber.

[0028] The length of the optical fiber and the reference temperature variation are substituted into a preset second time delay calculation formula to obtain the temperature drift time delay, and the preset second time delay calculation formula is:

[0029] ,

[0030] wherein, is the group refractive index of the optical fiber, is the length of the optical fiber, is the vacuum light speed, is the reference temperature variation, is the thermal expansion coefficient of the optical fiber, is the temperature drift time delay.

[0031] In the embodiment of the present application, the compensation time delay is calculated based on the ambient temperature information and the length of the optical fiber, and the compensation time delay comprises:

[0032] In the process of obtaining the optical carrier phase signal through the optical fiber, the synchronous clock is obtained based on the optical carrier phase signal and / or based on a preset time service module.

[0033] The second aspect of the present application provides a cable partial discharge monitoring system, comprising:

[0034] The acquisition processing unit is configured to obtain a voltage phase reference source, the voltage phase reference source being a standard alternating voltage signal of a substation; obtain a partial discharge signal of a cable; determine a phase position in the partial discharge signal of the cable based on a voltage zero-crossing point of the voltage phase reference source; generate a map based on the partial discharge signal of the cable and the phase position, the map comprising a phase-resolved partial discharge map and / or a phase-resolved pulse sequence map; and obtain a cable partial discharge monitoring result based on the map.

[0035] In the embodiments of the present application, the VEU unit and the MPU unit are further included, and the VEU unit is connected to the MPU unit through an optical fiber;

[0036] The VEU unit is configured to obtain a standard alternating voltage signal of the substation, convert the standard alternating voltage signal of the substation into an optical signal, obtain an optical carrier phase signal, and send the optical carrier phase signal to the MPU unit through the optical fiber.

[0037] The MPU unit is configured to obtain a voltage phase reference source based on the optical carrier phase signal, and send the voltage phase reference source to the acquisition processing unit.

[0038] In the embodiments of the present application, the VEU unit is arranged at a secondary circuit of the substation, and the VEU unit is connected to the secondary circuit of the substation through an electromagnetic shield cable.

[0039] In the embodiments of the present application, the MPU unit is arranged at a joint of the cable.

[0040] In the embodiments of the present application, the VEU unit comprises an acquisition subunit, a compensation subunit and an adjustment subunit.

[0041] The acquisition subunit is configured to acquire environmental temperature information and length of the optical fiber.

[0042] The compensation subunit is configured to calculate a compensation time delay based on the environmental temperature information and the length of the optical fiber.

[0043] The adjustment subunit is configured to convert the standard alternating voltage signal of the substation into an optical signal to obtain an optical carrier phase signal, and adjust a transmission timing of sending the optical carrier phase signal to the MPU unit based on the compensation time delay.

[0044] In the embodiment of the present application, the compensation subunit is specifically configured to calculate a static transmission delay based on the length of the optical fiber, calculate a temperature drift delay based on the ambient temperature information and the length of the optical fiber, and obtain a compensation delay amount based on the static transmission delay and the temperature drift delay.

[0045] The third aspect of the present application provides a cable partial discharge monitoring device, applied to each cable joint monitoring point, comprising:

[0046] A reference source acquisition module is configured to acquire a voltage phase reference source, which is a standard AC voltage signal of a substation.

[0047] A telecommunication signal acquisition module is configured to acquire a partial discharge signal of a cable.

[0048] A synchronization module is configured to determine a phase position in the partial discharge signal of the cable based on a voltage zero-crossing point of the voltage phase reference source.

[0049] A graph module is configured to generate a graph based on the partial discharge signal of the cable and the phase position, the graph comprising a phase-resolved partial discharge graph and / or a phase-resolved pulse sequence graph.

[0050] A monitoring module is configured to obtain a cable partial discharge monitoring result based on the graph.

[0051] In the embodiment of the present application, the reference source acquisition module comprises:

[0052] A recovery unit is configured to acquire an optical carrier phase signal through an optical fiber, the optical carrier phase signal being obtained by converting the standard AC voltage signal of the substation into an optical signal.

[0053] A conversion unit is configured to obtain the voltage phase reference source based on the optical carrier phase signal.

[0054] In the embodiment of the present application, the recovery unit comprises:

[0055] An information acquisition subunit is configured to acquire ambient temperature information and a length of the optical fiber.

[0056] A calculation subunit is configured to calculate a compensation delay amount based on the ambient temperature information and the length of the optical fiber.

[0057] An adjustment subunit is configured to acquire an optical carrier phase signal through an optical fiber and adjust a transmission timing of a signal transmitting end of the optical fiber based on the compensation delay amount.

[0058] The fourth aspect of the present application provides an electronic device, comprising:

[0059] at least one processor;

[0060] a memory connected with the at least one processor;

[0061] The memory stores instructions executable by the at least one processor, and the at least one processor implements the above cable partial discharge monitoring method by executing the instructions stored in the memory.

[0062] The fifth aspect of the present application provides a machine-readable storage medium, which stores instructions, and the instructions make the processor configured to execute the above cable partial discharge monitoring method when executed by the processor.

[0063] Through the above technical solution, by acquiring a voltage phase reference source, the voltage phase reference source is a standard alternating voltage signal of a substation; a partial discharge signal of a cable is acquired; a phase position is determined in the partial discharge signal of the cable based on a voltage zero point of the voltage phase reference source; a graph is generated based on the partial discharge signal of the cable and the phase position, the graph includes a phase-resolved partial discharge graph and / or a phase-resolved pulse sequence graph; and a cable partial discharge monitoring result is obtained based on the graph. The standard alternating voltage signal of the substation is directly used as a global phase reference, the graphs of all monitoring points are strictly aligned to the real system voltage zero point phase, the load factor interference problem existing in the current phase reference is fundamentally avoided, the graph statistical characteristics (discharge amount, phase distribution) can truly reflect the insulation defect characteristics, the graph distortion problem is solved, the cable partial discharge monitoring accuracy is greatly improved, and the discharge type recognition rate is improved by more than 30%. The method can be applied to power pipe gallery high-voltage cable online monitoring, can accurately measure the partial discharge signal of the high-voltage cable, and generate accurate PRPD / PRPS graphs, which helps to improve the intelligent level of power grid state monitoring and provides a new guarantee for the safety of intelligent substation equipment.

[0064] Other features and advantages of the embodiments of the present application will be described in detail in the following specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0065] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used together with the following specific implementation to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0066] Figure 1 The flowchart of the cable partial discharge monitoring method according to the embodiments of the present application is schematically shown;

[0067] Figure 2 The system architecture and workflow diagram of the prior art are schematically shown;

[0068] Figure 3 Fig. 1 schematically shows a cable partial discharge monitoring workflow diagram according to an embodiment of the present application;

[0069] Figure 4 Fig. 2 schematically shows a dual-mode tolerance diagram according to an embodiment of the present application;

[0070] Figure 5 Fig. 3 schematically shows a PRPD map phase offset comparison experimental result diagram according to an embodiment of the present application;

[0071] Figure 6 Fig. 4 schematically shows an optical fiber synchronization performance test data diagram according to an embodiment of the present application;

[0072] Figure 7 Fig. 5 schematically shows a system architecture and workflow diagram according to an embodiment of the present application;

[0073] Figure 8 Fig. 6 schematically shows a structure diagram of a cable partial discharge monitoring device according to an embodiment of the present application;

[0074] Figure 9 Fig. 7 schematically shows an internal structure diagram of a computer device according to an embodiment of the present application.

[0075] Legend of reference signs

[0076] 410-reference source acquisition module; 420-electrical signal acquisition module; 430-synchronization module; 440-map module; 450-monitoring module; A01-processor; A02-network interface; A03-internal memory; A04-display screen; A05-input device; A06-nonvolatile storage medium; B01-operating system; B02-computer program. DETAILED DESCRIPTION

[0077] The specific embodiments of the embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the embodiments of the present application, and are not intended to limit the embodiments of the present application.

[0078] It should be noted that the acquisition, transmission, storage, use, processing, etc. of data in the technical solutions of the present application comply with relevant provisions of laws and regulations. In the embodiments of the present application, some industry existing solutions, components, models, etc. may be mentioned, which should be considered as exemplary, and the purpose is only to illustrate the feasibility of the implementation of the technical solutions of the present application, but it does not mean that the applicant has or will necessarily use the solutions.

[0079] It should be noted that if the application embodiments involve directionality indication (such as up, down, left, right, front, back, …), the directionality indication is only used to explain the relative position relationship, motion condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directionality indication also changes accordingly.

[0080] In addition, if the application embodiments involve "first", "second" and the like, the "first", "second" and the like are only for description purposes, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person skilled in the art, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the application.

[0081] Term explanation:

[0082] VEU: its English full name is Voltage Evaluation Unit, Chinese full name: voltage detection unit or voltage evaluation unit.

[0083] MPU: its English full name is Main Processing Unit, Chinese full name is main processing unit.

[0084] Please refer to Figure 1 , Figure 1 The flowchart of a cable partial discharge monitoring method according to the embodiments of the application is schematically shown. The embodiments provide a cable partial discharge monitoring method, which is applied to each cable joint monitoring point and includes the following steps:

[0085] Step 210: obtaining a voltage phase reference source, which is a standard AC voltage signal of a substation;

[0086] In the embodiments, the standard AC voltage signal of the substation can be a power frequency voltage signal obtained at a secondary circuit of the substation, or a power frequency voltage signal of the secondary circuit of the substation is converted into an optical pulse signal for transmission, and then the optical pulse signal is demodulated and reconstructed by a high-speed photoelectric converter to output a power frequency sine wave. The voltage phase reference source can be a power frequency sine wave.

[0087] In some embodiments, the voltage phase reference source is obtained by:

[0088] First, an optical carrier phase signal is obtained through an optical fiber, the optical carrier phase signal being obtained by converting a standard AC voltage signal of the transformer substation into an optical signal;

[0089] In the embodiment, a signal processing device can be arranged at a PT secondary circuit of the transformer substation, and a core function of the signal processing device is to convert a power frequency voltage signal of the transformer substation secondary circuit into an anti-interference optical signal, to provide a high-precision voltage phase reference source for cable partial discharge monitoring. Specifically, a 57.7V / 100V power frequency voltage signal can be directly obtained from the transformer substation PT secondary circuit as an absolute phase reference of the power grid. In a specific implementation, the power frequency voltage signal can be connected through an electromagnetic shield cable twisted pair to avoid electromagnetic pollution in the transmission process. Then, the power grid harmonic noise (such as switching operation and power electronic device interference) can be filtered through an LC low-pass filter (cut-off frequency 100Hz). Then, a high-precision lithium niobate electro-optical modulator is used to convert the pure voltage signal into an optical pulse (wavelength 1310nm±0.1nm) to obtain an optical carrier phase signal. Then, the optical carrier phase signal can be transmitted to a data processing end through an optical fiber in a lossless and synchronous manner to obtain a voltage phase reference source. The optical fiber can be a single-mode armored optical fiber laid in a cable pipe gallery. The optical fiber itself is not affected by the electromagnetic field, and the transmission loss is less than 0.3dB / km (8km measured signal attenuation is less than 2.5dB). In this way, an undisturbed and lossless optical carrier phase signal can be obtained.

[0090] Then, a voltage phase reference source is obtained based on the optical carrier phase signal.

[0091] In the embodiment, the optical carrier phase signal can be demodulated and reconstructed through a high-speed photoelectric converter to output a power frequency sine wave, that is, to obtain a voltage phase reference source.

[0092] The optical carrier phase signal is obtained through an optical fiber, and then the optical carrier phase signal is converted to obtain a voltage phase reference source, so that the signal is not disturbed in the transmission process, a lossless signal can be obtained, the voltage phase reference source has the same phase as the standard AC voltage signal of the transformer substation, the phase drift is less than 0.1° in the temperature range of “-40℃~85℃” in actual measurement, and the phase stability in a harsh environment is ensured. This is helpful to improve the accuracy of cable partial discharge monitoring.

[0093] In some embodiments, in order to further ensure that each cable obtains a signal phase synchronization, dynamic time delay compensation can be performed on the optical pulse signal. That is, the optical carrier phase signal obtained through the optical fiber includes:

[0094] First, the ambient temperature information and the length of the optical fiber are obtained;

[0095] In the embodiment, the environmental temperature change of the optical fiber can be monitored in real time, which can be obtained by a distributed optical fiber temperature monitoring system and belongs to the prior art, and thus will not be described herein. The length of the optical fiber can be measured.

[0096] In the second step, the compensation delay amount is calculated based on the environmental temperature information and the length of the optical fiber.

[0097] In the embodiment, the dynamic delay compensation can be performed based on the environmental temperature information and the length of the optical fiber to eliminate the path delay.

[0098] In some embodiments, the compensation delay amount is calculated based on the environmental temperature information and the length of the optical fiber, including:

[0099] First, the static transmission delay is calculated based on the length of the optical fiber.

[0100] In the embodiment, the static transmission delay can be calculated by multiplying the group refractive index of the optical fiber and the length of the optical fiber by the ratio of the vacuum light speed.

[0101] Specifically, the length of the optical fiber can be substituted into a preset first delay calculation formula to obtain the static transmission delay, and the preset first delay calculation formula is:

[0102] ,

[0103] wherein, is the group refractive index of the optical fiber, and a typical value is 1.467, is the length of the optical fiber, is the vacuum light speed, and a typical value is 3×10 8 m / s, is the static transmission delay.

[0104] The length of the optical fiber can be substituted into the preset first delay calculation formula to quickly obtain the static transmission delay.

[0105] Then, the temperature drift delay is calculated based on the environmental temperature information and the length of the optical fiber.

[0106] In the embodiment, the temperature drift delay can be calculated by multiplying the group refractive index of the optical fiber and the length of the optical fiber by the ratio of the vacuum light speed, and then multiplying the thermal expansion coefficient of the optical fiber and the reference temperature change amount.

[0107] Specifically, the reference temperature change amount can be calculated based on the environmental temperature information of the optical fiber and a preset reference temperature. Then, the length of the optical fiber and the reference temperature change amount can be substituted into a preset second delay calculation formula to obtain the temperature drift delay, and the preset second delay calculation formula is:

[0108] ,

[0109] wherein, is the group refractive index of the optical fiber, is the length of the optical fiber, is the vacuum light speed, is the reference temperature variation, is the thermal expansion coefficient of the optical fiber, and a typical value is 5.5x10 -7 , is the temperature drift delay.

[0110] In this embodiment, the reference temperature variation can be expressed as: wherein, is the reference temperature, and a typical value is 25℃, is the real-time temperature of the optical fiber environment (which can be a multi-point average), in ℃.

[0111] By first calculating the reference temperature variation, and then substituting the length of the optical fiber and the reference temperature variation into the preset second delay calculation formula, the temperature drift delay can be quickly obtained.

[0112] Finally, based on the static transmission delay and the temperature drift delay, the compensation delay amount is obtained.

[0113] In this embodiment, the compensation delay amount can be composed of the static transmission delay + the temperature drift delay, i.e., the compensation delay amount can be expressed as:

[0114] .

[0115] By respectively calculating the static transmission delay based on the length of the optical fiber, calculating the temperature drift delay based on the environmental temperature information and the length of the optical fiber, and calculating the compensation delay amount based on the static transmission delay and the temperature drift delay, the compensation delay amount can be quickly and accurately calculated, which helps to accurately perform dynamic delay compensation.

[0116] Thirdly, the optical carrier phase signal is obtained through the optical fiber, and the transmission timing of the signal sending end of the optical fiber is adjusted based on the compensation delay amount.

[0117] In the embodiment, the signal processing device VEU unit can be deployed at the secondary circuit of the transformer substation PT to convert the power frequency voltage signal of the secondary circuit of the transformer substation into an anti-interference optical signal. The MPU unit is arranged at the cable joint to demodulate and reconstruct the optical pulse signal through a high-speed photoelectric converter and output a power frequency sine wave. The VEU unit and the MPU unit are connected through an optical fiber. The VEU unit (the signal transmitting end of the optical fiber) transmits the optical carrier phase signal to the MPU unit through the optical fiber and adjusts the timing of the transmitted optical signal according to the calculated compensation delay amount, so as to ensure the phase alignment of each MPU unit, that is, to ensure the cross-node synchronization.

[0118] Referring to Figure 6 , Figure 6 The figure shows the optical fiber synchronization performance test data according to the embodiment of the application. The 8km optical fiber link in a certain city is tested continuously for 72 hours under the condition of environmental temperature fluctuation (±5℃). The data is collected by using the Tektronix DPO71604C oscilloscope (sampling rate 50GS / s) combined with the optical time domain reflectometer. The test result shows that the optical fiber transmission delay is stably controlled within 30ns, which meets the nanosecond-level measurement requirement.

[0119] The environmental temperature information and the length of the optical fiber are acquired. The compensation delay amount is calculated based on the environmental temperature information and the length of the optical fiber. The optical carrier phase signal is acquired through the optical fiber, and the transmission timing of the signal transmitting end of the optical fiber is adjusted based on the compensation delay amount, so as to ensure the phase alignment of the signals corresponding to each cable.

[0120] Step 220: acquiring the partial discharge signal of the cable;

[0121] In the embodiment, the partial discharge signal of the cable can be acquired through a high-frequency current transformer (HFCT, High-Frequency Current Transformer). The above-mentioned partial discharge signal is a partial discharge current pulse signal.

[0122] Step 230: determining the phase position in the partial discharge signal of the cable based on the voltage zero-crossing point of the voltage phase reference source;

[0123] In the embodiment, the output of the voltage phase reference source is a pure power frequency sine wave, which can be monitored in real time, and the point where the sine wave crosses from negative to positive value is accurately identified, i.e. the voltage zero-crossing point. The phase position can be determined by time-stamping the voltage zero-crossing point of the voltage phase reference source in the partial discharge signal of the cable. A digital pulse signal is generated at each zero-crossing point, serving as the trigger reference of the entire data acquisition system. The pulse marks the beginning of each new power frequency cycle (0° phase). When a partial discharge pulse is detected, the system immediately calculates the time interval between the arrival time of the pulse and the last voltage zero-crossing reference, and according to the time interval and the known power frequency cycle (T, 20 ms for 50 Hz), the accurate phase position of the pulse can be calculated. The positioning error of the power frequency voltage sine wave zero-crossing point can be ensured to be ≤±0.05°.

[0124] Step 240: generating a map based on the partial discharge signal of the cable and the phase position, the map comprising a phase-resolved partial discharge map and / or a phase-resolved pulse sequence map;

[0125] In the embodiment, the system accumulates phase-labeled pulse data for several seconds to several minutes. Then, a two-dimensional coordinate system is created with phase (0°-360°) as the horizontal axis and discharge amplitude as the vertical axis. Each pulse is projected into the corresponding coordinate grid according to its phase and amplitude, and the frequency of discharge occurrence at that position is represented by color depth or point density, forming a two-dimensional PRPD map. On the basis of PRPD, a third dimension-time or power frequency cycle number is added. It can be understood that hundreds or thousands of consecutive PRPD maps are stacked in time sequence to form a three-dimensional data cube, which shows the distribution of partial discharge activity with phase and the evolution with time, obtaining the PRPS map.

[0126] Step 250: obtaining the cable partial discharge monitoring result based on the map.

[0127] In the embodiment, the voltage phase-aligned PRPD / PRPS map can be sent to the master station system, which can compare the voltage phase-aligned PRPD / PRPS map with the fault diagnosis feature library, identify the type of partial discharge, and obtain the cable partial discharge monitoring result.

[0128] The scheme will be described below with specific examples. Please refer to Figure 3 , Figure 3The schematic diagram illustrates the cable partial discharge monitoring workflow according to an embodiment of this application. The secondary voltage of the substation PT is directly acquired and used as a global phase reference source. After VUE filtering and photoelectric conversion into an optical signal, it is transmitted to the MPU via single-mode fiber with low latency and high bandwidth for photoelectric recovery conversion to reconstruct the original phase signal. PRPD / PRPS spectra can be generated through phase zero-point synchronization and acquisition of partial discharge pulses to obtain the cable partial discharge monitoring results.

[0129] Please refer to Figure 5 , Figure 5 The diagram schematically illustrates the experimental results of a phase shift comparison of PRPD spectra according to an embodiment of this application. Partial discharge pulses are timestamped under a voltage phase reference. The partial discharge acquisition and processing unit acquires the partial discharge signal and synthesizes PRPD / PRPS spectra based on the voltage-synchronized phase. The comparison reveals that: Traditional current method: the spectrum shifts by 20° when the load fluctuates, leading to misjudgment of the discharge type (metal tip discharge characteristics are misidentified as floating discharge due to the 20° phase shift); Using this scheme: the phase reference is constant, and the spectrum clearly presents the concentrated discharge area (such as internal discharge clusters near the voltage peak), accurately determining the tip-off discharge type.

[0130] In the above implementation process, a voltage phase reference source is acquired, which is the standard AC voltage signal of the substation; the partial discharge signal of the cable is acquired; based on the zero-crossing point of the voltage phase reference source, the phase position in the partial discharge signal of the cable is determined; based on the partial discharge signal of the cable and the phase position, a spectrum is generated, which includes a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum; based on the spectrum, the cable partial discharge monitoring result is obtained. By directly using the standard AC voltage signal of the substation as the global phase reference, the spectrum of each monitoring point is strictly aligned to the true system voltage zero-point phase, fundamentally avoiding the load factor interference problem existing in the current phase reference. This allows the statistical characteristics of the spectrum (discharge quantity, phase distribution) to truly reflect the insulation defect characteristics, solving the spectrum distortion problem and greatly improving the accuracy of cable partial discharge monitoring, increasing the discharge type identification rate by more than 30%. It can be applied to online monitoring of high-voltage cables in power utility tunnels, accurately measuring the partial discharge signal of high-voltage cables and generating accurate PRPD / PRPS spectra, helping to improve the intelligent level of power grid status monitoring and providing new protection for the safety of intelligent substation equipment.

[0131] In some embodiments, it also includes:

[0132] During the process of acquiring the optical carrier phase signal through the optical fiber, a synchronization clock is obtained based on the optical carrier phase signal and / or based on a preset timing module.

[0133] In this embodiment, please refer toFigure 4 , Figure 4 A schematic diagram illustrating a dual-mode disaster recovery scheme according to an embodiment of this application is provided. When the optical fiber is functioning normally, synchronization can be achieved using an optical signal (i.e., an optical carrier phase signal), meaning a synchronization clock is obtained based on the optical carrier phase signal. When the optical fiber is interrupted, the system automatically switches to a 50Hz synchronization clock generated by the built-in GPS / BeiDou module (i.e., a timing module). The backup clock phase jitter is <±0.5°, ensuring continuous system operation for ≥24 hours. Alternatively, the built-in GPS / BeiDou module (i.e., a timing module) can be used directly to generate the synchronization clock.

[0134] The system employs a dual-mode disaster recovery design, prioritizing optical signal synchronization for phase synchronization. After successful phase synchronization of the fiber optic signal, it also synchronizes the time stamp of the GPS / BeiDou module. When fiber optic transmission is unstable or interrupted, the synchronization clock of the GPS / BeiDou module is activated. This clock is calculated based on the last successful time stamp plus a multiple of 50Hz power frequency cycle.

[0135] Employing a dual-mode synchronization mechanism, the system can automatically switch to the timing module as a backup clock source when the primary fiber optic transmission fails, thus ensuring continuous operation under extreme conditions. Meanwhile, the modular design supports hot-swappable maintenance, resulting in high system robustness.

[0136] Figure 1 This is a flowchart illustrating the cable partial discharge monitoring method in this embodiment. It should be understood that, although... Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0137] Please refer to Figure 7 , Figure 7 This illustration schematically depicts the system architecture and workflow according to an embodiment of the present application. This embodiment provides a cable partial discharge monitoring system, including:

[0138] The acquisition and processing unit is used to acquire a voltage phase reference source, which is a standard AC voltage signal of a substation; acquire partial discharge signals of the cable; determine the phase position in the partial discharge signal of the cable based on the voltage zero-crossing point of the voltage phase reference source; generate a spectrum based on the partial discharge signal of the cable and the phase position, the spectrum including a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum; and obtain the cable partial discharge monitoring results based on the spectrum.

[0139] In this embodiment, the acquisition and processing unit can be a device with data processing capabilities, such as a computer or digital processor. The acquisition and processing unit acquires a voltage phase reference source, which is the standard AC voltage signal of the substation; acquires the partial discharge signal of the cable; determines the phase position in the partial discharge signal of the cable based on the zero-crossing point of the voltage phase reference source; generates a spectrum based on the partial discharge signal and the phase position, the spectrum including a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum; and obtains the cable partial discharge monitoring results based on the spectrum. By directly using the power frequency voltage signal of the substation's secondary circuit as the global phase reference, the spectrum at each monitoring point is strictly aligned to the true system voltage zero-point phase, fundamentally avoiding the load factor interference problem existing in the current phase reference. This allows the statistical characteristics of the spectrum (discharge quantity, phase distribution) to truly reflect the insulation defect characteristics, solving the spectrum distortion problem, greatly improving the accuracy of cable partial discharge monitoring, and increasing the discharge type identification rate by more than 30%. It can be applied to online monitoring of high-voltage cables in power utility tunnels, accurately measuring the partial discharge signal of high-voltage cables and generating accurate PRPD / PRPS maps, which helps to improve the intelligence level of power grid status monitoring and provides new protection for the safety of smart substation equipment.

[0140] It also includes a VEU unit and an MPU unit, wherein the VEU unit and the MPU unit are connected by optical fiber;

[0141] The VEU unit is used to acquire the standard AC voltage signal of the substation, convert the standard AC voltage signal of the substation into an optical signal, obtain an optical carrier phase signal, and send it to the MPU unit through the optical fiber;

[0142] The MPU unit is used to obtain a voltage phase reference source based on the optical carrier phase signal, and send the voltage phase reference source to the acquisition and processing unit.

[0143] In this embodiment, the VEU unit, or field acquisition unit, is used to convert the power frequency voltage signal of the substation secondary circuit into an anti-interference optical signal, providing a high-precision voltage phase reference source for cable partial discharge monitoring. A 57.7V / 100V power frequency voltage signal can be directly acquired from the substation PT secondary circuit as the absolute phase reference of the power grid. The signal is connected via an electromagnetically shielded twisted-pair cable to avoid electromagnetic pollution during transmission. The VEU unit includes a signal conditioning circuit (LC low-pass filter, cutoff frequency 100Hz) and a lithium niobate electro-optic modulator (wavelength tolerance ±0.1nm). The LC low-pass filter (cutoff frequency 100Hz) filters out power grid harmonic noise (such as switching operations and power electronic device interference). The high-precision lithium niobate electro-optic modulator converts the pure voltage signal into an optical pulse (wavelength 1310nm ±0.1nm). The MPU unit demodulates and reconstructs the optical pulse signal through a high-speed photoelectric converter, outputting a power frequency sine wave. It includes a photoelectric recovery module, which reconstructs the power frequency voltage waveform through a 16-bit DAC, with a phase recovery error of <±0.3°. For transmission distances ≤20km, a single optical fiber can simultaneously support at least 10 photoelectric phase recovery units (MPUs), enabling multi-node cascading expansion. Armored optical fibers can be used to mitigate electromagnetic interference. The acquisition and processing unit uses the voltage zero-crossing point reconstructed by the MPU units as a trigger reference to synchronously acquire partial discharge pulse data.

[0144] By setting up VEU and MPU units, high-quality 50Hz / 60Hz power frequency voltage signals can be directly acquired from the substation and used as a global phase reference source. These signals are converted into optical signals by a high-precision photoelectric conversion module and transmitted to the MPU unit at the monitoring site with low latency and high bandwidth via single-mode fiber. The original phase signal is then reconstructed through photoelectric reconstruction. This ensures that the voltage phase reference source is in phase with the standard AC voltage signal of the substation. Actual measurements show a phase drift of <0.1° within a temperature range of -40℃ to 85℃, ensuring phase stability even in harsh environments. This contributes to improving the accuracy of cable partial discharge monitoring.

[0145] In some embodiments, the VEU unit is located in the secondary circuit of the substation, and the VEU unit is connected to the secondary circuit of the substation via an electromagnetic shielded cable.

[0146] In this embodiment, the VEU unit includes a signal conditioning circuit (LC low-pass filter, cutoff frequency 100Hz) and a high-linearity lithium niobate electro-optic modulator (wavelength tolerance ±0.1nm). The signal is connected via an electromagnetically shielded twisted-pair cable to avoid electromagnetic pollution during transmission. The LC low-pass filter (cutoff frequency 100Hz) filters out grid harmonic noise (such as interference from switching operations and power electronic devices). This ensures that the standard AC voltage signal of the substation is not interfered with.

[0147] In some embodiments, the MPU unit is disposed at the connector of the cable.

[0148] In this embodiment, the MPU unit includes a photoelectric recovery module that reconstructs the power frequency voltage waveform using a 16-bit DAC, with a phase recovery error of <±0.3°. By deploying the MPU unit at the cable joint, the voltage phase signal can be processed locally, avoiding induced interference from long-distance cables and helping to improve the accuracy of partial discharge monitoring in cables.

[0149] In some embodiments, the MPU unit includes an acquisition subunit, a compensation subunit, and an adjustment subunit;

[0150] The acquisition subunit is used to acquire the ambient temperature information and length of the optical fiber;

[0151] The compensation subunit is used to calculate the compensation delay based on the ambient temperature information and length of the optical fiber.

[0152] The adjustment subunit is used to convert the power frequency voltage signal of the substation secondary circuit into an optical signal to obtain an optical carrier phase signal, and adjust the transmission timing of sending the optical carrier phase signal to the MPU unit based on the compensation delay amount.

[0153] Specifically, the compensation subunit is used to calculate the static transmission delay based on the length of the optical fiber, calculate the temperature drift delay based on the ambient temperature information and length of the optical fiber, and obtain the compensation delay amount based on the static transmission delay and the temperature drift delay.

[0154] By acquiring the ambient temperature and length of the optical fiber through the MPU unit, calculating the compensation delay based on the ambient temperature and length of the optical fiber, and acquiring the optical carrier phase signal through the optical fiber, and adjusting the transmission timing of the signal transmitting end of the optical fiber based on the compensation delay, the signal phase alignment of each cable can be guaranteed.

[0155] Please refer to Figure 8 , Figure 8 The schematic diagram illustrates the structure of a cable partial discharge monitoring device according to an embodiment of this application. This embodiment provides a cable partial discharge monitoring device applied to monitoring points at various cable joints, including a reference source acquisition module 410, an electrical signal acquisition module 420, a synchronization module 430, a graph module 440, and a monitoring module 450, wherein:

[0156] The reference source acquisition module 410 is used to acquire a voltage phase reference source, wherein the voltage phase reference source is a standard AC voltage signal of the substation.

[0157] Electrical signal acquisition module 420 is used to acquire partial discharge signals of the cable;

[0158] Synchronization module 430 is used to determine the phase position in the partial discharge signal of the cable based on the voltage zero crossing point of the voltage phase reference source.

[0159] The graph module 440 is used to generate a graph based on the partial discharge signal of the cable and the phase position, the graph including a phase-resolved partial discharge graph and / or a phase-resolved pulse sequence graph;

[0160] The monitoring module 450 is used to obtain the partial discharge monitoring results of the cable based on the spectrum.

[0161] The reference source acquisition module 410 includes:

[0162] The recovery unit is used to acquire an optical carrier phase signal via optical fiber, wherein the optical carrier phase signal is obtained by converting the standard AC voltage signal of the substation into an optical signal.

[0163] The conversion unit is used to obtain a voltage phase reference source based on the optical carrier phase signal.

[0164] The conversion unit includes:

[0165] An information acquisition subunit is used to acquire the ambient temperature information and length of the optical fiber;

[0166] The calculation subunit is used to calculate the compensation delay based on the ambient temperature information and length of the optical fiber;

[0167] The adjustment subunit is used to acquire the optical carrier phase signal through the optical fiber and adjust the transmission timing of the signal transmitting end of the optical fiber based on the compensation delay amount.

[0168] The cable partial discharge monitoring device includes a processor and a memory. The aforementioned reference source acquisition module 410, electrical signal acquisition module 420, synchronization module 430, spectrum module 440, and monitoring module 450 are all stored as program units in the memory. The processor executes the aforementioned program units stored in the memory to realize the corresponding functions.

[0169] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and partial discharge monitoring of cables can be performed by adjusting kernel parameters.

[0170] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0171] This invention provides a machine-readable storage medium storing a program that, when executed by a processor, implements the cable partial discharge monitoring method.

[0172] This invention provides a processor for running a program, wherein the program executes the cable partial discharge monitoring method during runtime.

[0173] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 9 As shown. The computer device includes a processor A01, a network interface A02, a display screen A04, an input device A05, and a memory (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A06. The non-volatile storage medium A06 stores an operating system B01 and a computer program B02. The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 stored in the non-volatile storage medium A06. The network interface A02 is used for communication with external terminals via a network connection. When the computer program is executed by the processor A01, it implements a method for monitoring partial discharge in cables. The display screen A04 can be a liquid crystal display (LCD) or an e-ink display. The input device A05 can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0174] Those skilled in the art will understand that Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0175] In one embodiment, the cable partial discharge monitoring device provided in this application can be implemented as a computer program, which can be implemented in the form of, for example... Figure 9 The computer device shown is running the program. The computer device's memory can store the various program modules that make up the cable partial discharge monitoring device, for example, Figure 8 The diagram shows a reference source acquisition module 410, an electrical signal acquisition module 420, a synchronization module 430, a spectrum module 440, and a monitoring module 450. The computer program comprised of these modules causes the processor to execute the steps in the cable partial discharge monitoring methods of the various embodiments of this application described in this specification.

[0176] Figure 9 The computer equipment shown can be used as follows Figure 8 The reference source acquisition module 410 in the cable partial discharge monitoring device shown executes step 210. The computer device can execute step 220 via the electrical signal acquisition module 420. The computer device can execute step 230 via the synchronization module 430. The computer device can execute step 240 via the graph module 440. The computer device can execute step 450 via the monitoring module 450.

[0177] This application provides an electronic device comprising: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the at least one processor implements the aforementioned cable partial discharge monitoring method by executing the instructions stored in the memory, applied to various cable joint monitoring points. When the processor executes the instructions, it performs the following steps:

[0178] Obtain a voltage phase reference source, wherein the voltage phase reference source is a standard AC voltage signal of a substation;

[0179] Acquire partial discharge signals from the cable;

[0180] Based on the zero-crossing point of the voltage phase reference source, the phase position is determined in the partial discharge signal of the cable.

[0181] Based on the partial discharge signal of the cable and the phase position, a spectrum is generated, which includes a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum.

[0182] Based on the aforementioned spectrum, the results of partial discharge monitoring of the cable were obtained.

[0183] In one embodiment, obtaining the voltage phase reference source includes:

[0184] The optical carrier phase signal is obtained by converting the standard AC voltage signal of the substation into an optical signal through optical fiber.

[0185] Based on the optical carrier phase signal, a voltage phase reference source is obtained.

[0186] In one embodiment, acquiring the optical carrier phase signal via optical fiber includes:

[0187] Obtain the ambient temperature information and length of the optical fiber;

[0188] Based on the ambient temperature information and length of the optical fiber, the compensation delay is calculated.

[0189] The optical carrier phase signal is obtained through an optical fiber, and the transmission timing of the signal transmitting end of the optical fiber is adjusted based on the compensation delay.

[0190] In one embodiment, calculating the compensation delay based on the ambient temperature information and length of the optical fiber includes:

[0191] The static transmission delay is calculated based on the length of the optical fiber.

[0192] The temperature drift delay is calculated based on the ambient temperature information and length of the optical fiber.

[0193] The compensation delay is obtained based on the static transmission delay and the temperature drift delay.

[0194] In one embodiment, calculating the static transmission delay based on the length of the optical fiber includes:

[0195] Substituting the length of the optical fiber into the preset first delay calculation formula, the static transmission delay is obtained. The preset first delay calculation formula is as follows:

[0196] ,

[0197] in, The refractive index of the fiber group, The length of the optical fiber. The speed of light in a vacuum. This refers to static transmission delay.

[0198] In one embodiment, calculating the temperature drift delay based on the ambient temperature information and length of the optical fiber includes:

[0199] Based on the ambient temperature information of the optical fiber and the preset reference temperature, the change in reference temperature is calculated.

[0200] Substituting the length of the optical fiber and the reference temperature change into the preset second time delay calculation formula, the temperature drift time delay is obtained. The preset second time delay calculation formula is as follows:

[0201] ,

[0202] in, The refractive index of the fiber group, The length of the optical fiber. The speed of light in a vacuum. For reference temperature change, The coefficient of thermal expansion of optical fiber. This is the temperature drift delay.

[0203] In one embodiment, it also includes:

[0204] During the process of acquiring the optical carrier phase signal through the optical fiber, a synchronization clock is obtained based on the optical carrier phase signal and / or based on a preset timing module.

[0205] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0206] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or 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 / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0207] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0208] 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 / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0209] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0210] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0211] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0212] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0213] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for monitoring partial discharge in cables, characterized in that, The method, applied to various cable joint monitoring points, includes: Obtain a voltage phase reference source, wherein the voltage phase reference source is a standard AC voltage signal of a substation; Acquire partial discharge signals from the cable; Based on the zero-crossing point of the voltage phase reference source, the phase position is determined in the partial discharge signal of the cable. Based on the partial discharge signal of the cable and the phase position, a spectrum is generated, which includes a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum. Based on the aforementioned spectrum, the partial discharge monitoring results of the cable were obtained; The method for obtaining the voltage phase reference source includes: The optical carrier phase signal is obtained by converting the standard AC voltage signal of the substation into an optical signal through optical fiber. Based on the optical carrier phase signal, a voltage phase reference source is obtained; The step of acquiring the optical carrier phase signal via optical fiber includes: Obtain the ambient temperature information and length of the optical fiber; Based on the ambient temperature information and length of the optical fiber, the compensation delay is calculated. The optical carrier phase signal is obtained through an optical fiber, and the transmission timing of the signal transmitting end of the optical fiber is adjusted based on the compensation delay amount. The calculation of the compensation delay based on the ambient temperature information and length of the optical fiber includes: The static transmission delay is calculated based on the length of the optical fiber. The temperature drift delay is calculated based on the ambient temperature information and length of the optical fiber. The compensation delay is obtained based on the static transmission delay and the temperature drift delay.

2. The cable partial discharge monitoring method according to claim 1, characterized in that, The calculation of the static transmission delay based on the length of the optical fiber includes: Substituting the length of the optical fiber into the preset first delay calculation formula, the static transmission delay is obtained. The preset first delay calculation formula is as follows: ， in, The refractive index of the fiber group, The length of the optical fiber. The speed of light in a vacuum. This refers to static transmission delay.

3. The cable partial discharge monitoring method according to claim 1, characterized in that, The temperature drift delay is calculated based on the ambient temperature information and length of the optical fiber, including: Based on the ambient temperature information of the optical fiber and the preset reference temperature, the change in reference temperature is calculated. Substituting the length of the optical fiber and the reference temperature change into the preset second time delay calculation formula, the temperature drift time delay is obtained. The preset second time delay calculation formula is as follows: ， in, The refractive index of the fiber group, The length of the optical fiber. The speed of light in a vacuum. For reference temperature change, The coefficient of thermal expansion of optical fiber. This is the temperature drift delay.

4. The cable partial discharge monitoring method according to claim 1, characterized in that, Also includes: During the process of acquiring the optical carrier phase signal through the optical fiber, a synchronization clock is obtained based on the optical carrier phase signal and / or based on a preset timing module.

5. A cable partial discharge monitoring system, characterized in that, include: The acquisition and processing unit is used to acquire a voltage phase reference source, which is a standard AC voltage signal of a substation. Acquire partial discharge signals from the cable; Based on the zero-crossing point of the voltage phase reference source, the phase position is determined in the partial discharge signal of the cable; based on the partial discharge signal of the cable and the phase position, a spectrum is generated, the spectrum including a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum; based on the spectrum, the cable partial discharge monitoring result is obtained; It also includes a VEU unit and an MPU unit, wherein the VEU unit and the MPU unit are connected by optical fiber; The VEU unit is used to acquire the standard AC voltage signal of the substation, convert the standard AC voltage signal of the substation into an optical signal, obtain an optical carrier phase signal, and send it to the MPU unit through the optical fiber; The MPU unit is used to obtain a voltage phase reference source based on the optical carrier phase signal, and send the voltage phase reference source to the acquisition and processing unit; The VEU unit includes an acquisition subunit, a compensation subunit, and an adjustment subunit; The acquisition subunit is used to acquire the ambient temperature information and length of the optical fiber; The compensation subunit is used to calculate the compensation delay based on the ambient temperature information and length of the optical fiber; specifically, the compensation subunit is used to calculate the static transmission delay based on the length of the optical fiber, calculate the temperature drift delay based on the ambient temperature information and length of the optical fiber, and obtain the compensation delay based on the static transmission delay and the temperature drift delay. The adjustment subunit is used to convert the standard AC voltage signal of the substation into an optical signal to obtain an optical carrier phase signal, and adjust the transmission timing of sending the optical carrier phase signal to the MPU unit based on the compensation delay amount.

6. The cable partial discharge monitoring system according to claim 5, characterized in that, The VEU unit is installed in the secondary circuit of the substation, and the VEU unit is connected to the secondary circuit of the substation through an electromagnetic shielded cable.

7. The cable partial discharge monitoring system according to claim 5, characterized in that, The MPU unit is located at the connector of the cable.

8. A cable partial discharge monitoring device, characterized in that, Applied to various cable joint monitoring points, including: The reference source acquisition module is used to acquire a voltage phase reference source, which is the standard AC voltage signal of the substation. An electrical signal acquisition module is used to acquire partial discharge signals from the cable. A synchronization module is used to determine the phase position in the partial discharge signal of the cable based on the zero-crossing point of the voltage phase reference source. The spectrum module is used to generate a spectrum based on the partial discharge signal of the cable and the phase position, the spectrum including a phase-resolved partial discharge spectrum and / or a phase-resolved pulse sequence spectrum; The monitoring module is used to obtain the partial discharge monitoring results of the cable based on the spectrum. The reference source acquisition module includes: The recovery unit is used to acquire an optical carrier phase signal via optical fiber, wherein the optical carrier phase signal is obtained by converting the standard AC voltage signal of the substation into an optical signal. A conversion unit is used to obtain a voltage phase reference source based on the optical carrier phase signal; The recovery unit includes: An information acquisition subunit is used to acquire the ambient temperature information and length of the optical fiber; A calculation subunit is used to calculate the compensation delay amount based on the ambient temperature information and length of the optical fiber; wherein, the calculation of the compensation delay amount based on the ambient temperature information and length of the optical fiber includes: calculating the static transmission delay based on the length of the optical fiber; calculating the temperature drift delay based on the ambient temperature information and length of the optical fiber; and obtaining the compensation delay amount based on the static transmission delay and the temperature drift delay. The adjustment subunit is used to acquire the optical carrier phase signal through the optical fiber and adjust the transmission timing of the signal transmitting end of the optical fiber based on the compensation delay amount.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; A memory connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the at least one processor implements the cable partial discharge monitoring method according to any one of claims 1 to 4 by executing the instructions stored in the memory.

10. A machine-readable storage medium storing instructions thereon, characterized in that, When executed by a processor, this instruction causes the processor to be configured to perform the cable partial discharge monitoring method according to any one of claims 1 to 4.

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