A cable dielectric loss monitoring method and system based on leakage current separation

Abstract

The application discloses a cable dielectric loss monitoring method and system based on leakage current separation, comprising: collecting three-phase ground currents and phase currents of a cable, and collecting a space voltage of an intermediate phase; calculating lead angles of the ground currents and the phase currents based on the ground currents, the phase currents and the space voltage; in any cycle, separating induced currents based on the lead angles of the ground currents and the phase currents at two different time points, and determining a phase angle of a leakage current; and calculating a dielectric loss tangent value of each phase based on the phase angle of the leakage current. The method can monitor the dielectric loss of the cable in real time under normal operation of the cable, can more accurately obtain the dielectric loss tangent value of the cable by separating the induced current and the leakage current and calculating a phase difference between the leakage current and the space voltage, and thus can more accurately evaluate the aging state of the cable, and the safety and reliability of a power system are improved.

Description

Technical Field

[0001] This invention relates to the field of electrical measurement technology, and more specifically, to a method and system for monitoring cable dielectric loss based on leakage current separation. Background Technology

[0002] Distribution network cables are numerous and have complex topologies. Under long-term operating conditions, they are susceptible to damage from unexplained external forces, internal water ingress, and other defects, leading to severe aging and significantly threatening safe and stable operation. Therefore, monitoring the insulation condition of distribution network cables is essential, enabling early warning and effectively preventing short-circuit accidents.

[0003] Dielectric loss is a crucial indicator of insulation aging in power equipment. Dielectric loss detection and monitoring of cables can reflect their operational status and guide appropriate operation and maintenance measures. Currently, offline detection is the primary method in engineering projects, using ultra-low frequency dielectric loss detectors to obtain cable dielectric loss values ​​during power outages. However, this method is limited by power outages and cannot promptly detect potential problems and defects.

[0004] There are two main methods for online monitoring of dielectric loss in power equipment: ① Injecting a 0.01Hz low-frequency voltage signal at the high-voltage end and extracting the phase angle difference between the injected voltage signal and the current signal of the same frequency at the grounding point to obtain the dielectric loss; ② Collecting the grounding current, separating the leakage current, and then simultaneously collecting the voltage to calculate the phase difference between the two to obtain the dielectric loss value.

[0005] While existing online monitoring technologies for cable dielectric loss have been proposed, they are still some distance from practical engineering applications. For example, low-frequency signal injection technology at the high-voltage end requires modification of the cable head structure of the distribution cabinet, resulting in complex wiring. Moreover, if the low-frequency signal amplitude is large, it can easily generate harmonics that affect power quality. If the low-frequency signal amplitude is small, the leakage current at the corresponding frequency is very weak and difficult to extract, leading to excessive errors.

[0006] Single-core cables, such as those with voltage levels of 35kV and above, often employ double-ended grounding and cross-interconnected grounding methods, resulting in complex grounding current components. For double-ended grounding, it is often necessary to sample the grounding current at both ends simultaneously, perform phase conversion and induced current separation to obtain the leakage current in the insulation medium. For cross-interconnected grounding, multiple current transformers need to be installed at the grounding point to eliminate induced current. These methods all require the installation of multiple current transformers and necessitate synchronous measures to separate induced current and obtain leakage current through current signal addition and subtraction, leading to high costs, cumbersome installation, and difficulty in widespread adoption.

[0007] Therefore, a new method for monitoring cable dielectric loss based on leakage current separation is needed. Summary of the Invention

[0008] This invention proposes a cable dielectric loss monitoring method and system based on leakage current separation to solve the problem of how to efficiently and accurately determine the dielectric loss of a single-core cable.

[0009] To address the aforementioned problems, according to one aspect of the present invention, a cable dielectric loss monitoring method based on leakage current separation is provided, the method comprising:

[0010] Collect the grounding current and phase current of the three phases of the cable, and collect the space voltage of the intermediate phase;

[0011] The lead angle of the ground current and phase current is calculated based on the ground current, phase current and space voltage.

[0012] Within any given cycle, the induced current is separated based on the leading angle of the ground current and phase current at two different times to determine the phase angle of the leakage current.

[0013] The dielectric loss tangent of each phase is calculated based on the phase angle of the leakage current.

[0014] Preferably, the method further includes:

[0015] The space voltage is acquired using a voltage sensor, which employs the principle of electromagnetic induction and a D-dot probe and integration restoration method to detect the waveform of the space voltage.

[0016] Preferably, the calculation of the lead angle of the ground current and phase current based on the ground current, phase current, and space voltage includes:

[0017] For any phase, calculate the phase difference between the ground current and phase current of that phase and the space voltage, respectively, to obtain the lead angle of that corresponding ground current and phase current.

[0018] Preferably, within any given period, the induced current is separated based on the lead angle of the ground current and phase current at two different times to determine the phase angle of the leakage current, including:

[0019] I di (t)∠θ di (t)=K·I i (t)∠θ k +I li ∠θ li ,

[0020] Among them, I at times t1 and t2 respectively di ∠θ di and I i Substitute these values ​​into the above formula and use the subtraction vector calculation method to calculate K and ∠θ. k and I di∠θ di ;I di (t), ∠θ di (t) represents the grounding current of phase i at time t and the corresponding lead angle, respectively; K is the proportional coefficient, I i (t) represents the phase current of phase i at time t; ∠θ k I is the phase angle of the induced current; lφ , ∠θ lφ These represent the leakage current amplitude and phase angle of phase i, respectively.

[0021] Preferably, the calculation of the dielectric loss tangent of each phase based on the phase angle of the leakage current includes:

[0022] δ m =tan(90°+θ) l2 ),

[0023] δ i =tan(θ) li -30°), θ li ∈ (30°, 120°), i=1,3,

[0024] δ i =tan(θ) li -150°), θ li ∈ (150°, 240°), i=1,3,

[0025] Where, δ m δ is the tangent of the dielectric loss angle of the intermediate phase. i θ is the tangent of the dielectric loss angle of phase i; li Let be the phase angle of the leakage current in phase i.

[0026] According to another aspect of the present invention, a cable dielectric loss monitoring system based on leakage current separation is provided, the system comprising:

[0027] The data acquisition unit is used to acquire the grounding current and phase current of the three phases of the cable, and to acquire the space voltage of the intermediate phase;

[0028] A lead angle calculation unit is used to calculate the lead angle of the ground current and the phase current based on the ground current, the phase current and the space voltage;

[0029] The leakage current calculation unit is used to separate the induced current based on the lead angle of the ground current and phase current at two different times in any cycle, and determine the phase angle of the leakage current.

[0030] The dielectric loss calculation unit is used to calculate the dielectric loss tangent of each phase based on the phase angle of the leakage current.

[0031] Preferably, the data acquisition unit further includes:

[0032] The space voltage is acquired using a voltage sensor, which employs the principle of electromagnetic induction to detect the waveform of the space voltage through a D-dot probe and an integration and restoration system.

[0033] Preferably, the lead angle calculation unit calculates the lead angle of the ground current and phase current based on the ground current, phase current, and space voltage, including:

[0034] For any phase, calculate the phase difference between the ground current and phase current of that phase and the space voltage, respectively, to obtain the lead angle of that corresponding ground current and phase current.

[0035] Preferably, the leakage current calculation unit, within any given period, separates the induced current based on the lead angle of the ground current and phase current at two different times to determine the phase angle of the leakage current, including:

[0036] I di (t)∠θ di (t)=K·I i (t)∠θ k +I li ∠θ li ,

[0037] Among them, I at times t1 and t2 respectively di ∠θ di and I i Substitute these values ​​into the above formula and use the subtraction vector calculation method to calculate K and ∠θ. k and I di ∠θ di ;I di (t), ∠θ di (t) represents the grounding current of phase i at time t and the corresponding lead angle, respectively; K is the proportional coefficient, I i (t) represents the phase current of phase i at time t; ∠θ k I is the phase angle of the induced current; lφ , ∠θ lφ These represent the leakage current amplitude and phase angle of phase i, respectively.

[0038] Preferably, the dielectric loss calculation unit calculates the dielectric loss tangent of each phase based on the phase angle of the leakage current, including:

[0039] δ m =tan(90°+θ) l2 ),

[0040] δ i =tan(θ) li-30°), θ li ∈ (30°, 120°), i=1,3,

[0041] δ i =tan(θ) li -150°), θ li ∈ (150°, 240°), i=1,3,

[0042] Where, δ m δ is the tangent of the dielectric loss angle of the intermediate phase. i θ is the tangent of the dielectric loss angle of phase i; li Let be the phase angle of the leakage current in phase i.

[0043] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the cable dielectric loss monitoring methods based on leakage current separation.

[0044] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0045] The aforementioned computer-readable storage medium; and

[0046] One or more processors for executing a program in the computer-readable storage medium.

[0047] This invention provides a cable dielectric loss monitoring method and system based on leakage current separation, comprising: acquiring the grounding current and phase current of the three phases of the cable, and acquiring the space voltage of the intermediate phase; calculating the lead angle of the grounding current and phase current based on the grounding current, phase current, and space voltage; separating the induced current based on the lead angle of the grounding current and phase current at two different times within any cycle to determine the phase angle of the leakage current; and calculating the dielectric loss tangent of each phase based on the phase angle of the leakage current. The method of this invention can monitor the dielectric loss of the cable in real time under normal operating conditions. By separating the induced current and leakage current and calculating the phase difference between the leakage current and the space voltage, the dielectric loss tangent of the cable can be obtained more accurately, thereby more accurately assessing the aging state of the cable. This achieves accurate and real-time monitoring of the dielectric loss of single-core cables, simplifies the installation and operation process, and can dynamically reflect the aging state of the cable, improving the safety and reliability of the power system. Attached Figure Description

[0048] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0049] Figure 1 This is a flowchart of a cable dielectric loss monitoring method 100 based on leakage current separation according to an embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of data acquisition according to an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of the equivalent circuit and integration circuit of the D-dot sensor according to an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram illustrating the relationship between the space voltage signal and the phase voltage according to an embodiment of the present invention;

[0053] Figure 5 This is a schematic diagram of the cable dielectric loss monitoring system 500 based on leakage current separation according to an embodiment of the present invention. Detailed Implementation

[0054] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0055] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0056] The technical problem to be solved by this invention is to overcome the gaps in the existing technology. First, the grounding current, space voltage and phase current of the single-core cable of the distribution network are monitored; then, the induced current is separated by calculating the correlation matrix of the phase current and the grounding current, and the leakage current is calculated; then, the dielectric loss tangent is obtained by calculating the phase difference between the leakage current and the space voltage, so as to assess the aging of the cable.

[0057] Figure 1 This is a flowchart of a cable dielectric loss monitoring method 100 based on leakage current separation according to an embodiment of the present invention. Figure 1As shown, the cable dielectric loss monitoring method based on leakage current separation provided by this invention can monitor the dielectric loss of a cable in real time under normal operating conditions. By separating the induced current and leakage current and calculating the phase difference between the leakage current and the space voltage, the dielectric loss tangent of the cable can be obtained more accurately, thereby more accurately assessing the aging state of the cable. This achieves accurate and real-time monitoring of the dielectric loss of a single-core cable, simplifies the installation and operation process, and can dynamically reflect the aging state of the cable, improving the safety and reliability of the power system. The cable dielectric loss monitoring method 100 based on leakage current separation provided by this invention starts from step 101. In step 101, the grounding current and phase current of the three phases of the cable are collected, and the space voltage of the intermediate phase is collected.

[0058] Preferably, the method further includes:

[0059] The space voltage is acquired using a voltage sensor, which employs the principle of electromagnetic induction and a D-dot probe and integration restoration method to detect the waveform of the space voltage.

[0060] In this invention, utilizing Figure 2 The device shown performs data acquisition. For example... Figure 2 As shown, the main monitoring locations include the three grounding currents of the cable (denoted as I). d1 I d2 I d3 ), three phase currents (I1, I2, I3) and the space voltage of the intermediate phase (U) m All parameters are vectors. These parameters are acquired simultaneously and in parallel by a single data acquisition unit, ensuring consistent acquisition time and enabling effective calculation of phase differences.

[0061] In this invention, the space voltage monitoring device is installed close to the middle phase of the three-phase cable head. For example... Figure 2 As shown, the monitoring sensor uses the principle of electromagnetic induction to detect the spatial electric field waveform through a D-dot probe and integration reconstruction method. The D-dot sensor is a differential capacitive voltage divider that indirectly measures voltage by measuring the differential components of the spatial electric field E or the electric displacement vector D. Generally, connecting an integration circuit after the D-dot sensor output voltage signal yields a voltage signal linearly proportional to the conductor voltage. The potential of the measured conductor is equivalent to V. i voltage source, C m C is the mutual capacitance between the sensor and the high-voltage conductor. s R is the stray capacitance to ground of the sensor. m For the ground load resistance, the sensor is equivalent to a load resistance of C. m C s and R mThis forms the simplest first-order RC circuit. The sensor's output signal V1(t) is input into a passive integrator circuit composed of R1 and C1. The integrator circuit outputs a signal V... o (t) represents the obtained measurement signal, which is a power frequency alternating signal, such as... Figure 4 As shown, since the sensor is located on both sides of the side phases, the space voltage vector U induced on the sensor by the middle phase and the side phases is symmetrical. sv The direction is consistent with the intermediate phase voltage.

[0062] In this invention, the grounding current of the cable under test is monitored and obtained by the above method. Phase current Space voltage signal It is important to note that during actual operation, attention should be paid to the orientation of the current sensor, and the grounding current at both ends should be in the positive direction from the cable flowing into the ground.

[0063] In step 102, the lead angle of the ground current and phase current is calculated based on the ground current, phase current and space voltage.

[0064] Preferably, the calculation of the lead angle of the ground current and phase current based on the ground current, phase current, and space voltage includes:

[0065] For any phase, calculate the phase difference between the ground current and phase current of that phase and the space voltage, respectively, to obtain the lead angle of that corresponding ground current and phase current.

[0066] In this invention, the synchronous acquisition device performs further FFT spectrum analysis on the above signal to extract the 50Hz power frequency AC component and calculates the phase difference angle between the ground current, phase current, and space voltage signal for each phase. Specifically, for any phase, the phase difference between the ground current and phase current of that phase and the space voltage is calculated to obtain the lead angle of that corresponding ground current and phase current. For example, taking the intermediate phase as an example, by subtracting the ground current and phase current of the intermediate phase from the space voltage, I can be obtained. d2 ∠θ d2 I²∠θ², U m If ∠0, then θ d2 θ1 and θ2 represent the lead angle of the grounding current and the lead angle of the phase current, respectively, with the intermediate phase as a reference.

[0067] In step 103, within any cycle, the induced current is separated based on the leading angle of the ground current and phase current at two different times to determine the phase angle of the leakage current.

[0068] Preferably, within any given period, the induced current is separated based on the lead angle of the ground current and phase current at two different times to determine the phase angle of the leakage current, including:

[0069] I di (t)∠θ di (t)=K·I i (t)∠θ k +I li ∠θ li ,

[0070] Among them, I at times t1 and t2 respectively di ∠θ di and I i Substitute these values ​​into the above formula and use the subtraction vector calculation method to calculate K and ∠θ. k and I di ∠θ di ;I di (t), ∠θ di (t) represents the grounding current of phase i at time t and the corresponding lead angle, respectively; K is the proportional coefficient, I i (t) represents the phase current of phase i at time t; ∠θ k I is the phase angle of the induced current; lφ , ∠θ lφ These represent the leakage current amplitude and phase angle of phase i, respectively.

[0071] In step 104, the dielectric loss tangent of each phase is calculated based on the phase angle of the leakage current.

[0072] Preferably, the calculation of the dielectric loss tangent of each phase based on the phase angle of the leakage current includes:

[0073] δ m =tan(90°+θ) l2 ),

[0074] δ i =tan(θ) li -30°), θ li ∈ (30°, 120°), i=1,3,

[0075] δ i =tan(θ) li -150°), θ li ∈ (150°, 240°), i=1,3,

[0076] Where, δ m δ is the tangent of the dielectric loss angle of the intermediate phase. i θ is the tangent of the dielectric loss angle of phase i; li Let be the phase angle of the leakage current in phase i.

[0077] In this invention, for any phase, the induced current is separated by the lead angle of the ground current and the phase current at two different times within any cycle, the phase angle of the leakage current is determined, and the dielectric loss tangent of each phase is calculated based on the phase angle of the leakage current.

[0078] The calculation example uses the middle phase (i=2) as an example. The magnitude of the induced current in a single-core cable is directly proportional to the phase current amplitude, and the proportionality coefficient changes with the operating environment and aging condition. In this case, the grounding current I... d2 ∠θ d2 It can be represented as:

[0079] I d2 (t1)∠θ d2 (t1)=K·I2(t1)∠θ k +I l2 ∠θ l2 (1)

[0080] I d2 (t2)∠θ d2 (t2)=K·I2(t2)∠θ k +I l2 ∠θ l2 (2)

[0081] In the above system of equations, K and I l2 ∠θ l2 , representing the proportionality coefficient of the induced current, the magnitude of the leakage current, and the phase angle, respectively, ∠θ k The phase angle represents the induced current.

[0082] In this invention, T is considered as a period, assuming that the cable will not experience accelerated aging within time T, and that the proportional coefficient K and leakage current vector value will not change during this time. I is monitored at different times (t1, t2) within T. d2 ∠θ d2 By substituting I2 into equations (1) and (2), K and ∠θ can be easily obtained. k and I l2 ∠θ l2 Among them, based on the vector calculation method of subtracting two equations, the value of K and ∠θ are first obtained. k Then, substituting into any formula, we can calculate I. l2 ∠θ l2 .

[0083] In this invention, load changes caused by user behavior at different time periods are considered. Therefore, T can be taken as 3 hours, which ensures that the difference in phase current amplitude at two times t1 and t2 is greater than 30%, making the K value more representative. If the difference in phase current amplitude cannot be guaranteed to be within 30% within T, the time span of T can be lengthened.

[0084] Following this logic, we can obtain I. l1 ∠θ l1 I l3 ∠θ l3 .

[0085] Finally, I was obtained. l2 ∠θ l2 Then, according to δm=tan(90°+θ) l2 The dielectric loss tangent δm of the intermediate phase can then be obtained.

[0086] Since the voltage reference phase is based on the middle phase, according to the 120° phase correction principle, the dielectric loss tangent of the other two phases is calculated as follows:

[0087] θ li ∈(30°, 120°) then δ i =tan(θ) li -30°);

[0088] θ li ∈(150°, 240°) then δ i =tan(θ) li -150°); i = 1, 3.

[0089] Table 1 shows the current and phase angle data for the intermediate phase at two different times. Based on the data in Table 1, the proportional coefficient and phase angle of the induced current are calculated as follows:

[0090]

[0091] Solving for K, we get K = 0.050403, θ k =47.76938, I l2 =0.88776, θ l2 = -89.58799, and by substituting this into the formula for calculating the dielectric loss tangent of the intermediate phase, we can obtain δ. m =tan(90°+θ) l2 = 0.00719.

[0092] Table 1. Data on current and angle of the intermediate phase at different times.

[0093] <![CDATA[Time t1]]> <![CDATA[Time t2]]> <![CDATA[Grounding current I d2 (A)]]> 2.0 2.5 <![CDATA[Leading angle θ d2 (°)]]> 30.27 33.85 <![CDATA[Phase current I2 (A)]]> 50.8 61.1 <![CDATA[Lead angle θ2 (°)]]> 20.81 25.62

[0094] Similarly, based on the above process, the dielectric loss tangent of the other two phases can be calculated.

[0095] The single-core cable dielectric loss monitoring method based on leakage current separation of the present invention has the following advantages:

[0096] (1) Realize online monitoring of cable dielectric loss:

[0097] This invention provides an online monitoring method that can monitor the dielectric loss of a cable in real time while the cable is operating normally, thus avoiding the inconvenience and potential risks caused by power outages.

[0098] (2) Improve monitoring accuracy and reliability:

[0099] By separating the induced current and the leakage current, and calculating the phase difference between the leakage current and the space voltage, the dielectric loss tangent (tanδ) of the cable can be obtained more accurately, thereby more precisely assessing the aging condition of the cable.

[0100] (3) Dynamic monitoring of cable aging:

[0101] By monitoring changes in leakage current over different time periods, the aging status of cables can be dynamically reflected, potential faults can be warned in a timely manner, short-circuit accidents can be prevented, and the safety and stability of the power system can be improved.

[0102] (4) Improve power quality:

[0103] This invention avoids interference from low-frequency signals on power quality, ensuring the stable operation of the power system.

[0104] In summary, the method of the present invention enables accurate and real-time monitoring of dielectric loss in single-core cables, simplifies installation and operation procedures, adapts to various grounding methods, and can dynamically reflect the aging status of cables, thereby improving the safety and reliability of power systems.

[0105] Figure 5 This is a schematic diagram of the cable dielectric loss monitoring system 500 based on leakage current separation according to an embodiment of the present invention. Figure 5 As shown, the cable dielectric loss monitoring system 500 based on leakage current separation provided by the embodiment of the present invention includes: a data acquisition unit 501, a lead angle calculation unit 502, a leakage current calculation unit 503, and a dielectric loss calculation unit 504.

[0106] Preferably, the data acquisition unit 501 is used to acquire the grounding current and phase current of the three phases of the cable, and to acquire the space voltage of the intermediate phase.

[0107] Preferably, the data acquisition unit 501 further includes:

[0108] The space voltage is acquired using a voltage sensor, which employs the principle of electromagnetic induction to detect the waveform of the space voltage through a D-dot probe and an integration and restoration system.

[0109] Preferably, the lead angle calculation unit 502 is used to calculate the lead angle of the ground current and the phase current based on the ground current, the phase current and the space voltage.

[0110] Preferably, the lead angle calculation unit 502 calculates the lead angle of the ground current and phase current based on the ground current, phase current, and space voltage, including:

[0111] For any phase, calculate the phase difference between the ground current and phase current of that phase and the space voltage, respectively, to obtain the lead angle of that corresponding ground current and phase current.

[0112] Preferably, the leakage current calculation unit 503 is used to separate the induced current based on the leading angle of the ground current and the phase current at two different times in any cycle, and determine the phase angle of the leakage current.

[0113] Preferably, the leakage current calculation unit 503, within any given period, separates the induced current based on the leading angles of the ground current and phase current at two different times to determine the phase angle of the leakage current, including:

[0114] I di (t)∠θ di (t)=K·I i (t)∠θ k +I li ∠θ li ,

[0115] Among them, I at times t1 and t2 respectively di ∠θ di and I i Substitute these values ​​into the above formula and use the subtraction vector calculation method to calculate K and ∠θ. k and I di ∠θ di ;I di (t), ∠θ di (t) represents the grounding current of phase i at time t and the corresponding lead angle, respectively; K is the proportional coefficient, I i (t) represents the phase current of phase i at time t; ∠θ k I is the phase angle of the induced current; lφ <θ lφ These represent the leakage current amplitude and phase angle of phase i, respectively.

[0116] Preferably, the dielectric loss calculation unit 504 is used to calculate the dielectric loss tangent of each phase based on the phase angle of the leakage current.

[0117] Preferably, the dielectric loss calculation unit 504 calculates the dielectric loss tangent of each phase based on the phase angle of the leakage current, including:

[0118] δ m =tan(90°+θ) l2 ),

[0119] δ i =tan(θ) li -30°), θ li ∈ (30°, 120°), i=1,3,

[0120] δ i =tan(θ) li -150°), θ li ∈ (150°, 240°), i=1,3,

[0121] Where, δ m δ is the tangent of the dielectric loss angle of the intermediate phase. i θ is the tangent of the dielectric loss angle of phase i; li Let be the phase angle of the leakage current in phase i.

[0122] The cable dielectric loss monitoring system 500 based on leakage current separation in this embodiment corresponds to the cable dielectric loss monitoring method 100 based on leakage current separation in another embodiment of this invention, and will not be described again here.

[0123] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the cable dielectric loss monitoring methods based on leakage current separation.

[0124] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0125] The aforementioned computer-readable storage medium; and

[0126] One or more processors for executing a program in the computer-readable storage medium.

[0127] The present invention has been described with reference to a few embodiments. However, it will be apparent to those skilled in the art that other embodiments besides those disclosed above fall equivalently within the scope of the present invention.

[0128] Generally, all terms used in this invention are interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A cable dielectric loss monitoring method based on leakage current separation, characterized in that, The method includes: Collect the grounding current and phase current of the three phases of the cable, and collect the space voltage of the intermediate phase; The lead angle of the ground current and phase current is calculated based on the ground current, phase current and space voltage. Within any given cycle, the induced current is separated based on the leading angle of the ground current and phase current at two different times to determine the phase angle of the leakage current. The dielectric loss tangent of each phase is calculated based on the phase angle of the leakage current; The calculation of the lead angle of the ground current and phase current based on the ground current, phase current, and space voltage includes: For any phase, calculate the phase difference between the ground current and phase current of that phase and the space voltage, respectively, to obtain the lead angle of the ground current and phase current of that phase. Within any given cycle, the induced current is separated based on the lead angle of the ground current and phase current at two different times to determine the phase angle of the leakage current, including: ， Among them, the times at t1 and t2 respectively and Substitute these values ​​into the above formula and use the subtraction vector calculation method to calculate K. and ; Let be the grounding current of phase i at time t and the corresponding lead angle, respectively; K is the proportional coefficient. Let be the phase current of phase i at time t; The phase angle of the induced current; , These represent the leakage current amplitude and phase angle of phase i, respectively.

2. The method according to claim 1, characterized in that, The method further includes: The space voltage is acquired using a voltage sensor, which employs the principle of electromagnetic induction and a D-dot probe and integration restoration method to detect the waveform of the space voltage.

3. The method according to claim 1, characterized in that, The dielectric loss tangent of each phase is calculated based on the phase angle of the leakage current, including: d m =tan(90°+θ) l2 ) d i = tan(θ) li - 30°), θ li ∈(30°,120°),i=1.3, d i = tan(θ) li - 150°), θ li ∈(150°,240°),i=1.3, Where, δ m δ is the tangent of the dielectric loss angle of the intermediate phase. i θ is the tangent of the dielectric loss angle of phase i; li Let be the phase angle of the leakage current in phase i.

4. A cable dielectric loss monitoring system based on leakage current separation, characterized in that, The system includes: The data acquisition unit is used to acquire the grounding current and phase current of the three phases of the cable, and to acquire the space voltage of the intermediate phase; A lead angle calculation unit is used to calculate the lead angle of the ground current and the phase current based on the ground current, the phase current and the space voltage; The leakage current calculation unit is used to separate the induced current based on the lead angle of the ground current and phase current at two different times in any cycle, and determine the phase angle of the leakage current. The dielectric loss calculation unit is used to calculate the dielectric loss tangent of each phase based on the phase angle of the leakage current. The lead angle calculation unit calculates the lead angle of the ground current and phase current based on the ground current, phase current, and space voltage, including: For any phase, calculate the phase difference between the ground current and phase current of that phase and the space voltage, respectively, to obtain the lead angle of the ground current and phase current of that phase. The leakage current calculation unit, within any given period, separates the induced current based on the lead angle of the ground current and phase current at two different times, and determines the phase angle of the leakage current, including: ， Among them, the times at t1 and t2 respectively and Substitute these values ​​into the above formula and use the subtraction vector calculation method to calculate K. and ; Let be the grounding current of phase i at time t and the corresponding lead angle, respectively; K is the proportional coefficient. Let be the phase current of phase i at time t; The phase angle of the induced current; , These represent the leakage current amplitude and phase angle of phase i, respectively.

5. The system according to claim 4, characterized in that, The data acquisition unit further includes: The space voltage is acquired using a voltage sensor, which employs the principle of electromagnetic induction to detect the waveform of the space voltage through a D-dot probe and an integration and restoration system.

6. The system according to claim 4, characterized in that, The dielectric loss calculation unit calculates the dielectric loss tangent of each phase based on the phase angle of the leakage current, including: d m =tan(90°+θ) l2 ) d i = tan(θ) li - 30°), θ li ∈(30°,120°),i=1.3, d i = tan(θ) li - 150°), θ li ∈(150°,240°),i=1.3, Where, δ m δ is the tangent of the dielectric loss angle of the intermediate phase. i θ is the tangent of the dielectric loss angle of phase i; li Let be the phase angle of the leakage current in phase i.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-3.

8. An electronic device, characterized in that, include: The computer-readable storage medium as described in claim 7; as well as One or more processors for executing a program in the computer-readable storage medium.

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