Online insulation monitoring method, device, electronic equipment and storage medium for capacitor type equipment

Abstract

The present invention discloses an online insulation monitoring method, device, electronic device and storage medium for capacitor-type equipment. The method includes: obtaining the operating data and standard data of the three-phase lightning arrester and dry-type current transformer on the same bus; using the optimal solution algorithm model to calculate the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase according to the operating data, standard data and the preset virtual reference voltage phase initial value; establishing a capacitor-type equipment insulation state detection model based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, as well as the optimal solution of the three-phase virtual reference voltage phase, so as to determine the insulation state of the capacitor-type equipment through the capacitor-type equipment insulation state detection model. The technical solution provided by the embodiment of the present invention solves the problem that traditional measurement methods cannot achieve online monitoring, resulting in untimely discovery of operational defects of capacitor-type equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution networks, and in particular to an insulation online monitoring method, device, electronic equipment and storage medium for capacitor-type equipment. Background Art

[0002] Capacitor-type devices account for more than 40% of substations. The insulation quality of these capacitor-type devices will affect the reliability of power supply to the power grid, and in serious cases, it will also pose a threat to the safety of other power equipment and personnel in the station.

[0003] Lightning arresters and dry-type current transformers (CTs) (hereinafter referred to as "dry-type CTs") are two key capacitive devices in power systems. Their operational safety is crucial to the performance of lightning protection and the ability of secondary metering to accurately reflect the system's operating status and provide accurate signals to protective devices. The resistive current and dielectric loss tanδ of lightning arresters and dry-type CTs can reflect the degree of insulation aging in capacitive devices. By measuring resistive current and dielectric loss tanδ, the insulation condition of lightning arresters and dry-type CTs can be assessed.

[0004] Traditional offline testing methods for resistive current and dielectric loss tanδ of lightning arresters and dry-type CTs involve disconnecting the equipment from power at regular intervals and then disassembling it for inspection. This offline method is not only unable to detect internal insulation discharge in operating lightning arresters and dry-type CTs, but also involves working at height, posing significant safety risks to personnel. Long intervals between preventive testing cycles can delay the timely detection of equipment operational defects. Furthermore, lightning arresters can also be tested live, but this requires obtaining a PT voltage signal. Given the emphasis on safety, extracting the secondary voltage of the voltage transformer does not align with the technological development direction for safe and simple live testing of lightning arresters. Dry-type CTs currently can only be tested while powered off, not while powered on. In the context of digital operations and maintenance, there is an urgent need for online methods and means to measure resistive current and dielectric loss in dry-type CTs. Summary of the Invention

[0005] The present invention provides a method, device, electronic device and storage medium for online insulation monitoring of capacitor-type equipment, so as to solve the problem that traditional measurement methods cannot realize online monitoring, resulting in untimely detection of operational defects of capacitor-type equipment.

[0006] According to one aspect of the present invention, a method for online insulation monitoring of a capacitor-type device is provided, wherein the capacitor-type device includes a lightning arrester and a dry-type current transformer. The method comprises:

[0007] Obtaining operating data and standard data of the lightning arrester and the dry-type current transformer on the same bus three phases; the operating data includes the full current fundamental amplitude and phase of the lightning arrester, and the full current fundamental amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental and the voltage fundamental of the lightning arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer;

[0008] According to the operating data, the standard data and the preset initial value of the virtual reference voltage phase, the optimal solution algorithm model is used to calculate the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase;

[0009] According to the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, and the optimal solution of the three-phase virtual reference voltage phase, a capacitive device insulation state detection model is established to determine the insulation state of the capacitive device through the capacitive device insulation state detection model.

[0010] Optionally, before calculating the optimal solution of the full current fundamental wave and voltage fundamental wave phase difference of the three-phase arrester and the dry-type current transformer, and the optimal solution of the three-phase virtual reference voltage phase using the optimal solution algorithm model based on the operating data, the standard data and the preset virtual reference voltage phase initial value, the method further includes:

[0011] Obtaining a first phase-to-phase current phase difference between devices of the same type and different types and a second phase-to-phase current phase difference between devices of the same phase and different types;

[0012] judging whether the lightning arrester and the dry-type current transformer in the same group are degraded according to the first inter-phase current phase difference and the second in-phase current phase difference;

[0013] In the absence of degradation, the steps of obtaining the optimal solution of the full current fundamental wave and voltage fundamental wave phase difference of the three-phase lightning arrester and the dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase, are performed based on the operating data, the standard data and the preset virtual reference voltage phase initial value, using the optimal solution algorithm model.

[0014] Optionally, the step of calculating the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer, and the optimal solution of the three-phase virtual reference voltage phase using an optimal solution algorithm model based on the operating data, the standard data, and the preset virtual reference voltage phase initial value includes:

[0015] Calculating a first target resistive current according to the arrester full current fundamental amplitude, the dry-type current transformer full current fundamental amplitude, the arrester full current fundamental and voltage fundamental phase difference, and the dry-type current transformer full current fundamental and voltage fundamental phase difference;

[0016] Calculating a first target phase difference and a second target phase difference according to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry-type current transformer, and an initial value of a preset virtual reference voltage phase;

[0017] Calculating a second target resistive current according to the full current fundamental amplitude of the lightning arrester, the full current fundamental amplitude of the dry-type current transformer, the first target phase difference, and the second target phase difference;

[0018] Calculating a resistive current error and a mean square error of the resistive current error according to the first target resistive current and the second target resistive current;

[0019] When the mean square error satisfies a mean square error threshold, obtaining an optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester and the dry-type current transformer;

[0020] The optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave is calculated based on the optimal solution for the phase difference between the three-phase virtual reference voltage.

[0021] Optionally, calculating the first target resistive current according to the full current fundamental amplitude of the arrester, the full current fundamental amplitude of the dry-type current transformer, the phase difference between the full current fundamental and the voltage fundamental of the arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer includes:

[0022] The first target resistive current is calculated using the following formula:

[0023] Where, I RMP is the first target resistive current of the arrester, I MP is the fundamental amplitude of the arrester's full current, θ MP The phase difference between the fundamental wave of the total current and the fundamental wave of the voltage of the arrester;

[0024] I RCP is the first target resistive current of the dry-type current transformer, I CP is the full current fundamental amplitude of the dry-type current transformer, θ CP It is the phase difference between the full current fundamental wave and voltage fundamental wave of the dry-type current transformer;

[0025] Calculating the first target phase difference and the second target phase difference according to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry-type current transformer, and the preset virtual reference voltage phase initial value includes:

[0026] The first target phase difference and the second target phase difference are calculated using the following formula:

[0027] Where θ MP_1 is the first target phase difference, is the fundamental phase of the arrester's full current, The preset virtual reference voltage phase initial value of the lightning arrester;

[0028] Where θ CP_1 is the second target phase difference, is the full current fundamental phase of the dry-type current transformer, It is the preset virtual reference voltage phase initial value of the dry-type current transformer;

[0029] Calculating the second target resistive current according to the full current fundamental amplitude of the arrester, the full current fundamental amplitude of the dry-type current transformer, the first target phase difference, and the second target phase difference includes:

[0030] The second target resistive current is calculated using the following formula:

[0031] Where, I RMP_1 is the second target resistive current of the arrester;

[0032] Where, I RCP_1 is the second target resistive current of the dry-type current transformer;

[0033] Calculating a resistive current error and a mean square error of the resistive current error according to the first target resistive current and the second target resistive current includes:

[0034] The resistive current error is calculated using the following formula:

[0035] ΔI RMP =I RMP_1 -I RMP Where, ΔI RMP is the resistive current error of the arrester;

[0036] ΔI RCP =I RCP_1 -I RCP Where, ΔI RCP is the resistive current error of the dry-type current transformer;

[0037] The mean square error of the resistive current error is calculated using the following formula:

[0038] Where, σ M_1 is the mean square error of the arrester’s resistive current, ΔI RMA , ΔI RMB , ΔI RMC The average value of P = A, B, C phase;

[0039] Where, σ C_1 is the mean square error of the resistive current error of the dry-type current transformer, ΔI RCA , ΔI RCB , ΔI RCC The average value of P = A, B, C phase;

[0040] Calculating the optimal solution for the three-phase virtual reference voltage phase according to the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave includes:

[0041] The following formula is used to calculate the optimal solution of the three-phase virtual reference voltage phase:

[0042] Where, It is the optimal solution for the three-phase virtual reference voltage phase of the lightning arrester;

[0043] Where, It is the optimal solution for the three-phase virtual reference voltage phase of dry-type current transformer.

[0044] Optionally, the step of calculating the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer, and the optimal solution of the three-phase virtual reference voltage phase using an optimal solution algorithm model based on the operating data, the standard data, and the preset virtual reference voltage phase initial value further includes:

[0045] When the mean square error does not meet the mean square error threshold, the first target phase difference and the second target phase difference are adjusted, and the optimal solution of the three-phase virtual reference voltage phase is recalculated until the mean square error threshold is met or the number of loop iterations is reached.

[0046] Optionally, establishing a capacitive device insulation state detection model based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave and the optimal solution of the three-phase virtual reference voltage phase, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model includes:

[0047] Using a group synchronous measurement method, based on a preset time interval, the full current fundamental wave amplitude and phase sequence of the lightning arrester and the dry-type current transformer are measured;

[0048] Obtaining a third phase current phase difference between devices of the same type and different types and a fourth phase current phase difference between devices of the same phase and different types;

[0049] judging whether the lightning arrester and the dry-type current transformer in the same group are degraded according to the third inter-phase current phase difference and the fourth in-phase current phase difference;

[0050] In the absence of degradation, calculating a third target phase difference according to an optimal solution of the full current fundamental wave phase of the lightning arrester and the dry-type current transformer and the phase of the three-phase virtual reference voltage;

[0051] Calculating a phase difference error and a mean square error of the phase difference error between the third target phase difference and an optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the dry-type current transformer;

[0052] In a case where the mean square error satisfies the mean square error threshold, normal and slightly degraded states of the capacitive device are determined, and resistive current and dielectric loss are output.

[0053] Optionally, after judging whether the lightning arrester and the dry-type current transformer in the same group are degraded according to the third inter-phase current phase difference and the fourth in-phase current phase difference, the method further includes:

[0054] In the case of degradation, separating the arrester of the degraded phase and the full current fundamental phase of the dry-type current transformer;

[0055] According to the optimal solution of the three-phase virtual reference voltage phase and the full current fundamental phase of the lightning arrester and the dry-type current transformer in the degraded phase, the fourth target phase difference is calculated, and based on the separated full current fundamental amplitude of the lightning arrester and the dry-type current transformer in the degraded phase and the calculated fourth target phase difference, the resistive current and dielectric loss of the degraded phase are output.

[0056] According to another aspect of the present invention, there is provided an online insulation monitoring device for a capacitor-type device, wherein the capacitor-type device includes a lightning arrester and a dry-type current transformer, and the online insulation monitoring device includes:

[0057] An acquisition module, the acquisition module is used to obtain the operating data and standard data of the lightning arrester and the dry-type current transformer of the same bus three-phase; the operating data includes the full current fundamental amplitude and phase of the lightning arrester, the full current fundamental amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental and the voltage fundamental of the lightning arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer;

[0058] A calculation module, the calculation module being configured to calculate, based on the operating data, the standard data, and a preset initial value of the virtual reference voltage phase, an optimal solution algorithm model for calculating the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer, as well as the optimal solution for the three-phase virtual reference voltage phase;

[0059] A determination module is used to establish a capacitive device insulation state detection model based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, and the optimal solution of the three-phase virtual reference voltage phase, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model.

[0060] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the insulation online monitoring method according to any embodiment of the present invention when executed.

[0061] According to another aspect of the present invention, an electronic device is provided, comprising:

[0062] at least one processor; and

[0063] a memory communicatively connected to the at least one processor; wherein,

[0064] The memory stores a computer program executable by the at least one processor. The computer program is executed by the at least one processor so that the at least one processor can execute the insulation online monitoring method according to any embodiment of the present invention.

[0065] The technical solution provided by the embodiment of the present invention implements a scheme for measuring the three-phase lightning arrester and dry-type CT group on the same busbars A, B, and C by analyzing the correlation between the installation positions, equivalent circuits, and phases of lightning arresters and dry-type CTs in the substation. Without taking the PT voltage signal of the busbar on the transmission line side where the lightning arrester and dry-type CT are located, the optimal solution algorithm model is trained by measuring the full leakage current of the lightning arrester and dry-type CT to obtain the optimal solution phase of the three-phase virtual reference voltage; using the optimal solution of the three-phase virtual reference voltage phase, the full current sequence of the lightning arrester and dry-type CT obtained by subsequent timed triggering measurement is analyzed in real time, and the current status of the lightning arrester or dry-type CT (normal, slightly degraded, or degraded) can be detected, and the resistive current and dielectric loss sequence of the three-phase lightning arrester and dry-type CT are calculated according to the timestamp, and the dynamic change trend of the resistive current and dielectric loss of the lightning arrester and dry-type CT of the capacitive equipment is perceived, and then its insulation status is evaluated. It avoids power outages, personnel climbing, safety risks, and shortens the detection cycle. It can realize real-time and reliable evaluation of the insulation status of lightning arresters and dry-type CTs, which is conducive to early, accurate and rapid diagnosis of the insulation status of lightning arresters and dry-type CTs, predicting equipment operation risks, and thus timely eliminating potential fault hazards.

[0066] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0068] Figure 1 A flowchart of a method for online insulation monitoring of a capacitor type device provided by an embodiment of the present invention;

[0069] Figure 2 A schematic diagram of the installation position of an online insulation monitoring system for capacitor-type equipment provided by an embodiment of the present invention;

[0070] Figure 3 A phase relationship diagram of the total current, resistive current, and capacitive current provided by an embodiment of the present invention;

[0071] Figure 4 A technical route for an online insulation monitoring method for capacitor-type equipment provided by an embodiment of the present invention;

[0072] Figure 5Flowchart of iterative training of the optimal solution algorithm model provided by an embodiment of the present invention;

[0073] Figure 6 Optimal solution algorithm model diagram provided by an embodiment of the present invention;

[0074] Figure 7 A vector diagram of the inter-phase and in-phase relationships provided by an embodiment of the present invention;

[0075] Figure 8 A flow chart of an insulation status detection algorithm for a capacitor-type device provided in an embodiment of the present invention;

[0076] Figure 9 A model diagram of an algorithm for detecting the insulation status of a capacitor-type device provided in an embodiment of the present invention;

[0077] Figure 10 A schematic structural diagram of an online insulation monitoring device for capacitor-type equipment provided by an embodiment of the present invention;

[0078] Figure 11 A structural schematic diagram of an electronic device for an online insulation monitoring method for a capacitor-type device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0079] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0080] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0081] Figure 1This is a flowchart of a method for online insulation monitoring of a capacitor type device provided by an embodiment of the present invention. This embodiment is applicable to online insulation monitoring of capacitor type devices. The method can be performed by an online insulation monitoring device for capacitor type devices. The online insulation monitoring device can be implemented in the form of hardware and / or software. The online insulation monitoring device can be configured in any electronic device with communication function. The capacitor type device includes a lightning arrester and a dry-type current transformer. Figure 1 , the insulation online monitoring method includes:

[0082] S110. Obtain operating data and standard data of a three-phase lightning arrester and a dry-type current transformer on the same bus.

[0083] Among them, the operating data includes the full current fundamental amplitude and phase of the lightning arrester, and the full current fundamental amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental and voltage fundamental of the lightning arrester, and the full current fundamental and voltage fundamental of the dry-type current transformer.

[0084] Specifically, the operating data and standard data of the three-phase lightning arresters and dry-type CTs on the same busbars A, B, and C are obtained. An online insulation monitoring system for capacitor-type equipment includes three lightning arrester current monitoring devices, three dry-type CT current monitoring devices, and an edge gateway deployed in the substation room. With the B-phase lightning arrester monitoring terminal as the group leader, the other five monitoring terminals are triggered through a synchronization antenna to perform synchronous measurement of the full leakage current; the data is uniformly transmitted back to the group leader via wireless communication, and the group leader then uniformly uploads the data to the edge gateway. The edge gateway centrally manages and analyzes the data reported by the monitoring terminals.

[0085] For example, taking phase B as an example, Figure 2 A schematic diagram of the installation position of an insulation online monitoring system for a capacitor type device provided by an embodiment of the present invention, see Figure 2 , including busbar, lightning arrester, traditional lightning strike counter, lightning arrester current monitoring device connected in parallel on both sides of the mechanical lightning strike counter, dry-type CT, dry-type CT current monitoring device and through-type current transformer. The through-type current transformer is directly mounted on the dry-type CT grounding down conductor position.

[0086] Specifically, the B-phase arrester current monitoring device automatically wakes up according to the time setting, and the pulse triggers the A and C-phase arrester current monitoring devices to synchronize measurements to obtain the amplitude and phase of the full current fundamental of the three-phase arrester in the substation; after receiving the synchronization acquisition instruction from the B-phase arrester current monitoring device, the dry-type CT current monitoring device synchronizes and triggers the measurement to obtain the amplitude and phase of the full current fundamental of the three-phase dry-type CT. Based on the resistive current and dielectric loss of the arrester and dry-type CT on the same bus detected by factory or test data, the phase difference θ between the full current fundamental of the three-phase arrester and dry-type CT and the voltage fundamental MP ,θCP As a reference standard.

[0087] S120. Based on the operating data, standard data and the preset initial value of the virtual reference voltage phase, the optimal solution algorithm model is used to calculate the optimal solution of the full current fundamental wave and voltage fundamental wave phase difference of the three-phase lightning arrester and dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase.

[0088] Among them, the preset virtual reference voltage phase initial value It can be pre-set according to standard data, for example, the initial value of the virtual reference voltage phase can be Set to 90°.

[0089] Specifically, Figure 3 The phase relationship diagram of the total current, resistive current and capacitive current provided by the embodiment of the present invention is shown in FIG. Figure 3 , Ix is the full current, I R is the resistive current, Ic is the capacitive current, U is the voltage fundamental wave, ∠θ is the phase difference between the full current fundamental wave and the voltage fundamental wave; ∠δ is the dielectric loss angle; according to the full current fundamental wave amplitude and phase of the three-phase lightning arrester, the full current fundamental wave amplitude and phase of the three-phase dry-type CT, the phase difference θ between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and dry-type CT MP ,θ CP , and preset the initial value of the virtual reference voltage phase Establish an optimal solution algorithm model, iteratively train the measurement data of the arrester and dry-type CT group, and obtain the optimal solution θ of the phase difference between the full current fundamental wave and voltage fundamental wave of the three-phase arrester and dry-type CT MP_2 ,θ CP_2 , and the corresponding three-phase virtual reference voltage phase optimal solution

[0090] S130. Establish a capacitive device insulation state detection model based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, and the optimal solution of the three-phase virtual reference voltage phase, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model.

[0091] Specifically, the optimal solution of the three-phase virtual reference voltage phase is used Establish a capacitive equipment insulation state detection model, perform real-time analysis on the arrester and dry-type CT full current fundamental sequence obtained by subsequent timed trigger measurement, and use the phase difference of the current between different devices of the same type and the current phase difference of the same-phase but different types of devices to separate the deterioration of the arrester or dry-type CT, and distinguish between normal, slightly deteriorated and deteriorated insulation of the arrester or dry-type CT. Accurately calculate the resistive current and dielectric loss parameters of the arrester and dry-type CT in these three situations, thereby sensing the change trend of the arrester insulation state. For example, Figure 4 As shown, Figure 4 A technical route of an online insulation monitoring method for capacitor-type equipment provided in an embodiment of the present invention.

[0092] The technical solution provided by the embodiment of the present invention implements a scheme for measuring the three-phase lightning arrester and dry-type CT group on the same busbars A, B, and C by analyzing the correlation between the installation positions, equivalent circuits, and phases of lightning arresters and dry-type CTs in the substation. Without taking the PT voltage signal of the busbar on the transmission line side where the lightning arrester and dry-type CT are located, the optimal solution algorithm model is trained by measuring the full leakage current of the lightning arrester and dry-type CT to obtain the optimal solution phase of the three-phase virtual reference voltage; using the optimal solution of the three-phase virtual reference voltage phase, the full current sequence of the lightning arrester and dry-type CT obtained by subsequent timed triggering measurement is analyzed in real time, and the current status of the lightning arrester or dry-type CT (normal, slightly degraded, or degraded) can be detected, and the resistive current and dielectric loss sequence of the three-phase lightning arrester and dry-type CT are calculated according to the timestamp, and the dynamic change trend of the resistive current and dielectric loss of the lightning arrester and dry-type CT of the capacitive equipment is perceived, and then its insulation status is evaluated. It avoids power outages, personnel climbing, safety risks, and shortens the detection cycle. It can realize real-time and reliable evaluation of the insulation status of lightning arresters and dry-type CTs, which is conducive to early, accurate and rapid diagnosis of the insulation status of lightning arresters and dry-type CTs, predicting equipment operation risks, and thus timely eliminating potential fault hazards.

[0093] Figure 5 For the iterative training flow chart of the optimal solution algorithm model provided by the embodiment of the present invention, see Figure 5 Specifically, step 1, group measurement:

[0094] The A, B, and C three-phase lightning arresters and dry-type CTs on the same busbar in a substation were measured 10 times repeatedly. The B-phase lightning arrester current monitoring device was used as the group leader. It automatically woke up according to the time setting and triggered the other A and C phase lightning arrester current monitoring devices and A, B, C three-phase dry-type CT current monitoring devices through pulse signals to perform full current synchronous measurement. The accurate full current fundamental amplitude and phase were obtained after taking the average value. Among them, I MP 、 is the amplitude and phase of the fundamental wave of the arrester's full current; I CP , It is the amplitude and phase of the full current fundamental wave of the dry-type CT (P = A, B, C phase).

[0095] Step 2: Model training: Based on the factory or test data of the same busbar three-phase lightning arrester, dry-type CT resistive current and dielectric loss, the phase difference θ between the full current fundamental wave and the voltage fundamental wave is calculated. MP and θ CP , with θ MP and θ CP(P = A, B, C phase) as a reference standard, the phase difference between the full current fundamental wave and voltage fundamental wave of the three-phase lightning arrester and dry-type CT under ideal conditions can be expressed as follows:

[0096] θ MA ,θ MB ,θ MC ,θ CA ,θ CB ,θ CC ;

[0097] See Figure 6 , Figure 6 This is a diagram of the optimal solution algorithm model provided by an embodiment of the present invention.

[0098] ① Input quantity:

[0099] a) Measured quantity: Amplitude of the fundamental wave of the full current of the three-phase arrester I MP and phase The amplitude of the fundamental wave of the full current of the three-phase dry CT is I CP and phase

[0100] b) Target quantity: Based on the factory or test data of the three-phase arrester on the same bus, the resistive current and dielectric loss of the dry-type CT, the phase difference θ between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester is calculated. MP , and the phase difference θ between the full current fundamental wave and voltage fundamental wave of the three-phase dry CT CP ;

[0101] c) Introduced quantity: Since the actual A, B and C three-phase bus voltage phases are unknown, the initial value of the virtual reference voltage phase of phase B is introduced. Based on the 120° phase difference of the three-phase voltages, the initial value of the preset three-phase virtual reference voltage phase is calculated. The arrester and dry-type CT resistive current is doubled as the deterioration judgment standard, and the arrester degradation threshold D is set. MT and dry CT degradation threshold D CT According to the convergence simulation of the mean square error of the resistive current error of the arrester and the dry-type CT, the mean square error threshold σ of the resistive current error of the arrester and the dry-type CT is introduced. MT_1 and σ CT_1 , and the number of loop iterations Count.

[0102] ②Process calculation amount:

[0103] a) Use the phase difference between the phase currents of different devices of the same type (the first phase current phase difference) and the phase difference between the currents of devices of the same phase but different types (the second same-phase current phase difference) to determine whether the three-phase lightning arresters and dry-type CTs in the same group are degraded;

[0104] The specific explanation of the phase difference between the phase currents of different devices of the same type (the first phase current phase difference) is as follows:

[0105] See also Figure 7 , Figure 7 This is a vector diagram of the relationship between phases and in-phase provided by an embodiment of the present invention. Taking a lightning arrester as an example, the phase difference between the AB phase, AC phase, and BC phase currents should theoretically be 120° (balanced state). If the phase difference between phase A and phases B and C is unbalanced, the change in the phase difference between the AB phase and AC phase currents exceeds the arrester degradation threshold D. MT =5°, it can be determined that the arrester of phase A has deteriorated; the same can be said for phases B and C.

[0106] Taking a dry-type CT as an example, the phase difference between the AB phase, AC phase, and BC phase currents should theoretically be 120° (balanced state). If the phase difference between phase A and phases B and C is unbalanced, the change in the phase difference between the AB phase and AC phase currents exceeds the dry-type CT degradation threshold D. CT =1°, it can be determined that the coherent CT of phase A has deteriorated; the same logic can be applied to the deterioration of phases B and C;

[0107] The specific explanation of the current phase difference between the same-phase but different types of devices (the second same-phase current phase difference) is as follows:

[0108] Taking the arrester and dry-type CT on the A-phase bus as an example, the theoretical phase difference between the arrester phase A and the dry-type CT_A phase current is 4°. If the arrester phase A degrades, the change in the phase difference between the arrester phase A and the dry-type CT_A phase current exceeds the arrester degradation threshold D. MT =5°, it can be determined that the A-phase lightning arrester has deteriorated; if the CT_A phase deteriorates, the phase difference change between the lightning arrester A phase and the dry CT_A phase current exceeds the dry CT degradation threshold D CT =1°, it can be determined that the coherent CT of phase A has degraded; the degradation of phases B and C can be determined in the same way.

[0109] b) If (a) is judged as yes, then the data of the arrester and dry-type CT degradation phases are eliminated and do not participate in the optimal solution calculation, and vice versa;

[0110] In the absence of degradation, the first target resistive current is calculated based on the full current fundamental amplitude of the lightning arrester, the full current fundamental amplitude of the dry-type current transformer, the phase difference between the full current fundamental and the voltage fundamental of the lightning arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer.

[0111] Specifically, the first target resistive current is calculated using the following formula:

[0112] Where, IRMP is the first target resistive current of the arrester, I MP is the fundamental amplitude of the arrester's full current, θ MP The phase difference between the fundamental wave of the total current and the fundamental wave of the voltage of the arrester;

[0113] I RCP is the first target resistive current of the dry-type current transformer, I CP is the full current fundamental amplitude of the dry-type current transformer, θ CP It is the phase difference between the full current fundamental wave and voltage fundamental wave of the dry-type current transformer.

[0114] A first target phase difference and a second target phase difference are calculated according to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry-type current transformer, and an initial value of a preset virtual reference voltage phase.

[0115] Specifically, the first target phase difference and the second target phase difference are calculated using the following formula:

[0116] Where θ MP_1 is the first target phase difference, is the fundamental phase of the arrester's full current, The preset virtual reference voltage phase initial value of the lightning arrester;

[0117] Where θ CP_1 is the second target phase difference, is the full current fundamental phase of the dry-type current transformer, It is the preset initial value of the virtual reference voltage phase of the dry-type current transformer.

[0118] The second target resistive current is calculated according to the full current fundamental wave amplitude of the lightning arrester, the full current fundamental wave amplitude of the dry-type current transformer, the first target phase difference and the second target phase difference.

[0119] Specifically, the second target resistive current is calculated using the following formula:

[0120] Where, I RMP_1 is the second target resistive current of the arrester;

[0121] Where, I RCP_1 is the second target resistive current of the dry-type current transformer.

[0122] Calculating a resistive current error and a mean square error of the resistive current error according to the first target resistive current and the second target resistive current;

[0123] Specifically, the resistive current error is calculated using the following formula:

[0124] ΔI RMP =I RMP_1 -I RMP Where, ΔI RMP is the resistive current error of the arrester;

[0125] ΔI RCP =I RCP_1 -I RCP Where, ΔI RCP is the resistive current error of the dry-type current transformer;

[0126] The mean square error of the resistive current error is calculated using the following formula:

[0127] Where, σ M_1 is the mean square error of the arrester’s resistive current, ΔI RMA , ΔI RMB , ΔI RMC The average value of P = A, B, C phase;

[0128] Where, σ C_1 is the mean square error of the resistive current error of the dry-type current transformer, ΔI RCA , ΔI RCB , ΔI RCC The average value of P = A, B, C phase.

[0129] Determine whether the mean square error meets the mean square error threshold σ of the arrester and dry-type CT resistive current error MT_1 and σ CT_1 Requirements: When the mean square error meets the mean square error threshold, obtain the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester and dry-type current transformer.

[0130] When the mean square error does not meet the mean square error threshold, the first target phase difference and the second target phase difference are adjusted, and the optimal solution of the three-phase virtual reference voltage phase is recalculated until the mean square error threshold is met or the number of loop iterations is reached.

[0131] The optimal solution of the three-phase virtual reference voltage phase is calculated based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave.

[0132] Specifically, the following formula is used to calculate the optimal solution of the three-phase virtual reference voltage phase:

[0133] Where, It is the optimal solution for the three-phase virtual reference voltage phase of the lightning arrester;

[0134] Where, It is the optimal solution for the three-phase virtual reference voltage phase of dry-type current transformer.

[0135] Furthermore, according to the optimal solution θ of the phase difference between the full current fundamental wave and voltage fundamental wave of the lightning arrester and dry-type CT, MP_2 ,θ CP_2 , calculate the resistive current I of the three-phase lightning arrester and dry-type CT RMP_2 , I RCP_2 (P = A, B, C phase);

[0136]

[0137] Optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester and dry-type CT MP_2 ,θ CP_2 , the dielectric loss factor tanδ of three-phase arrester and dry-type CT can be calculated MP_2 tanδ CP_2 (P = A, B, C phase);

[0138] tanδ MP_2 =tan(90°-θ MP_2 );

[0139] tanδ CP_2 =tan(90°-θ CP_2 );

[0140] For example, Table 1 finds the optimal solution (stage 1)

[0141]

[0142]

[0143] Table 2 Phase relationship (stage 1)

[0144]

[0145] Phase 1 is specifically shown in Table 1. The target quantity, measured quantity (averaged from 10 repeated measurements), and introduced quantity are input. Phase relationship Table 2 shows that the phase differences between the phase currents of different devices of the same type and the current phase differences between devices of the same phase but different types are normal (AB / BC / CA / CT_A-CT_B / CT_B-CT_C / CT_C-CT_A differ by approximately 120°, and CT_A-A / CT_B-B / CT_C-C differ by approximately 4°). Therefore, the arrester and dry-type CT are considered normal.

[0146] Using the optimal solution algorithm model, through cyclic iteration, it is found that the mean square error of the resistive current error of the arrester and dry-type CT converges to 1.2μA and 5.6μA, which are set as the mean square error threshold σ of the resistive current error of the arrester and dry-type CT. MT_1 and σ CT_1 ; Under the condition of satisfying two mean square error threshold conditions at the same time, the optimal solution θ of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT is obtained P_2 , where the phase difference between the fundamental wave of the total current and the fundamental wave of the voltage of the three-phase arrester A, B and C is θ MP_2 The phase difference between the fundamental current and fundamental voltage of the three-phase dry CT of A, B and C is 85.3°, 85° and 84.95° respectively. CP_2 They are 89.13°, 89.08° and 89.15° respectively.

[0147] According to the optimal solution θ of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and dry-type CT P_2 , calculate the optimal A, B and C three-phase virtual reference voltage They are 164.28°, 44.28°, and 284.28°, respectively, satisfying the conditions that the in-phase virtual reference voltage is consistent, the three-phase virtual reference voltage is balanced, and the phase difference between the phases (AB / BC / CA, CT_A-CT_B / CT_B-CT_C / CT_C-CT_A) is 120°.

[0148] In addition, according to the amplitude of the full current fundamental wave of the three-phase lightning arrester and dry-type CT in the measured quantity I MP , I CP , and the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave θ P_2 (including θ MP_2 ,θ CP_2 ), and further calculate the resistive current I of the three-phase arrester and dry-type CT RMP_2 , I RCP_2 and dielectric loss tanδ MP_2 tanδ CP_2 , as the benchmark for the insulation state parameters in stage 2.

[0149] Figure 8 For the flow chart of the capacitance type device insulation state detection algorithm provided by the embodiment of the present invention, see Figure 8 ,Using group synchronous measurement method, based on the preset time interval, the full current fundamental amplitude and phase sequence of the lightning arrester and dry-type current transformer are measured.

[0150] Specifically, step 1, group measurement: continuously perform group synchronous measurement on the A, B, and C three-phase lightning arresters and dry-type CTs on the same bus in a substation, with the B-phase lightning arrester current monitoring device as the group leader, automatically waking up according to the time setting, and triggering other A and C phase lightning arrester current monitoring devices and A, B, and C three-phase dry-type CT current monitoring devices through pulse signals to perform full current synchronous measurement, and obtain the dynamic A, B, and C three-phase lightning arresters and dry-type CT full current fundamental wave amplitude and phase sequence.

[0151] Among them, I MP 、 is the amplitude and phase of the fundamental wave of the arrester's full current; I CP , It is the amplitude and phase of the dry-type CT full current fundamental wave (P = A, B, C phase). Figure 9 , Figure 9 This is a model diagram of the capacitance device insulation status detection algorithm provided by an embodiment of the present invention.

[0152] Obtain the third phase-to-phase current phase difference between different devices of the same type and the fourth same-phase current phase difference between same-phase but different types of devices; determine whether there is degradation in the same group of lightning arresters and dry-type current transformers based on the third phase-to-phase current phase difference and the fourth same-phase current phase difference; if there is no degradation, calculate the third target phase difference based on the optimal solution of the full current fundamental wave phase of the lightning arrester and dry-type current transformer and the three-phase virtual reference voltage phase.

[0153] Calculating a phase difference error and a mean square error of the phase difference error between the third target phase difference and an optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer;

[0154] When the mean square error satisfies a mean square error threshold, normal and slightly degraded states of the capacitive device are determined, and resistive current and dielectric loss are output.

[0155] In the presence of degradation, the degraded phase lightning arrester and the full current fundamental phase of the dry-type current transformer are separated; the fourth target phase difference is calculated based on the optimal solution of the three-phase virtual reference voltage phase and the full current fundamental phase of the degraded phase lightning arrester and the dry-type current transformer, and the degraded phase resistive current and dielectric loss are output based on the full current fundamental amplitude of the lightning arrester and the dry-type current transformer separated from the degraded phase and the calculated fourth target phase difference.

[0156] Specifically, ① Input:

[0157] a) Measured quantity: Amplitude of the fundamental wave of the full current of the three-phase arrester I MP and phase Sequence; amplitude of the fundamental wave of the three-phase dry CT full current I CP and phase sequence.

[0158] c) Introduced quantity: Call the optimal three-phase virtual reference voltage phase obtained in stage 1 And the corresponding optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the dry CT MP_2 ,θ CP_2 , the arrester and dry-type CT resistive current is doubled as the deterioration judgment standard, and the arrester degradation threshold D is set. MT and dry CT degradation threshold D CT ; The arrester and dry-type CT resistive current is increased by 0.2 times as the judgment standard for slight degradation, and the mean square error thresholds of the arrester and dry-type CT phase difference errors are set to σ MT_2 and σ CT_2 .

[0159] ②Process calculation amount:

[0160] a) Use the phase difference between the phase currents of different devices of the same type and the phase difference between devices of the same phase but different types to determine whether the arresters and dry-type CTs in the same group, collected at different timestamps, have degraded. (The degradation criteria are the same as those explained in the calculation of process ② in stage 1--->step 2--->a) for the phase difference between the phase currents of different devices of the same type and the phase difference between devices of the same phase but different types, and are not further explained here.)

[0161] b) If (a) is judged as yes, separate the degraded phase arrester or dry-type CT full current fundamental phase The data (assuming that the A-phase lightning arrester or dry-type CT deteriorates after a certain time stamp) does not participate in the phase difference θ between the full current fundamental wave and the voltage fundamental wave at the current moment. MP_3 ,θ CP_3 Calculation, directly perform step (h), and vice versa;

[0162] c) The fundamental phase of the total current of the arrester and dry-type CT obtained by timing trigger measurement With the optimal three-phase virtual reference voltage phase Calculate the third target phase difference θ MP_3 ,θ CP_3 sequence;

[0163]

[0164] d) According to the phase difference sequence θ between the full current fundamental wave and the voltage fundamental wave MP_3 ,θ CP_3 , and the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave θ MP_2 ,θ CP_2 , calculate the phase difference error Δθ between the two MP , Δθ CP sequence;

[0165] Δθ MP =θ MP_3 -θ MP_2

[0166] Δθ CP =θ CP_3 -θ CP_2

[0167] e) Error Δθ of the phase difference between the full current fundamental wave and voltage fundamental wave of the arrester and dry-type CT MP , Δθ CP Sequence, calculate the mean square error σ M_2 , σ C_2 To characterize the overall discreteness of the phase difference between the full current fundamental wave and voltage fundamental wave of the lightning arrester and dry-type CT, the formula is as follows:

[0168]

[0169] in, is Δθ MA , Δθ MB , Δθ MC The average value of is Δθ CA , Δθ CB , Δθ CC The average value of P = A, B, C phase.

[0170] f) Determine whether the mean square error is less than the mean square error threshold σ of the arrester and dry-type CT phase difference error MT_2 , σ CT_2 If yes, then the current insulation state of the arrester or dry-type CT is normal; if not, the error Δθ of the phase difference between the fundamental current and the fundamental voltage of the arrester and dry-type CT is used. MP , Δθ CP The contribution to the mean square error is used to further determine the equipment types where slight degradation occurs.

[0171] The outputs of the A, B, and C phase arresters and dry-type CTs for normal and slightly degraded conditions are as follows:

[0172] g) Using the phase difference θ between the full current fundamental wave and the voltage fundamental wave at the current moment MP_3 ,θ CP_3 , calculate the arrester and dry-type CT resistive current I RMP_3 , I RCP_3 (P = A, B, C phase);

[0173]

[0174] The phase difference θ between the fundamental wave of the full current and the fundamental wave of the voltage at the current moment is used MP_3 ,θCP_3 , and the dielectric loss angle δ MP_3 , δ CP_3 The dielectric loss tanδ can be calculated by the mutual redundancy relationship MP_3 tanδ CP_3 (P=A, B, C phase).

[0175] tanδ MP_3 =tan(90°-θ MP_3 )

[0176] tanδ CP_3 =tan(90°-θ CP_3 )

[0177] If the A-phase lightning arrester or dry-type CT deteriorates after a certain timestamp, the output is as follows:

[0178] h) Using the latest three-phase virtual reference voltage phase The phase of the separated A-phase degraded arrester and the dry-type CT full current fundamental wave Calculate the fourth target phase difference θ between the current fundamental wave and voltage fundamental wave of the A-phase degraded lightning arrester and dry-type CT MP_4 ,θ CP_4 Sequence, and finally calculate the resistive current I of the A-phase degraded lightning arrester and dry-type CT RMP_4 , I RCP_4 Sequence (P = Phase A)

[0179]

[0180] The phase difference θ between the current fundamental wave and voltage fundamental wave of the A-phase deterioration arrester and dry-type CT is used. MP_4 ,θ CP_4 and dielectric loss angle δ MP_4 , δ CP_4 The dielectric loss tanδ of the A-phase degraded arrester and dry-type CT can be calculated based on the mutual redundancy relationship. MP_4 tanδ CP_4 sequence (P = Phase A).

[0181] tanδ MA_4 =tan(90°-θ MA_4 )

[0182] tanδ CA_4 =tan(90°-θ CA_4 )

[0183] For example, Table 3 Normal situation

[0184]

[0185] Table 4 Phase relationship under normal conditions

[0186]

[0187] An example of normal situation in stage 2 is shown in Table 3. The input measurement quantity (the full current sequence of the arrester and dry-type CT collected by timed triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase Phase relationship Table 4 shows that the phase differences between the phase currents of different devices of the same type and the current phase differences between devices of the same phase but different types are normal (the deviations of AB / BC / CA from 120° are controlled within the range of (0°, 1°); the deviations of CT_A-CT_B / CT_B-CT_C from 120° are controlled within the range of (0°, 0.2°); and the deviations of CT_A-A / CT_B-B / CT_C-C from 4° are controlled within the range of (0°, 1°). It can be determined that the arrester and dry-type CT are not deteriorated.

[0188] Using the capacitor type equipment status detection algorithm, the full current fundamental phase of the non-degraded lightning arrester and dry CT is The optimal three-phase virtual reference voltage phase obtained in stage 1 is used Calculate the phase difference θ between the full current fundamental wave and the voltage fundamental wave MP_3 ,θ CP_3 They are 85.13°, 84.84°, 85.05°, 89.05°, 89.15°, and 89.04° respectively, and are consistent with the optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT. MP_2 ,θ CP_2 Subtract (85.3°, 85°, 84.95°, 89.13°, 89.08°, 89.15°) to get the phase difference error Δθ MP , Δθ CP They are -0.17°, -0.16°, 0.1°, -0.08°, 0.07°, and -0.11° respectively. The mean square error of the phase difference is used to calculate σ. M_2 , σ C_2 The overall discreteness is characterized by 0.13° and 0.08°, which are less than the set threshold. σ CT_2 =0.13, indicating that the currently calculated set of measurements is normal.

[0189] The phase difference θ between the full current fundamental wave and the voltage fundamental wave is used MP_3 ,θ CP_3 , where the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase arresters A, B and C are 85.13°, 84.84° and 85.05° respectively; the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase dry CTs A, B and C are 89.05°, 89.15° and 89.04° respectively, and the amplitude of the full current fundamental wave in the measurement quantity IMP , I CP , calculate the arrester and dry-type CT resistive current I RMP_3 , I RCP_3 and dielectric loss tanδ MP_3 tanδ CP_3 .

[0190] Table 5 Slight deterioration of lightning arrester

[0191]

[0192] Table 6 Phase relationship of arrester in case of slight degradation

[0193]

[0194] An example of a slightly degraded arrester in stage 2 is shown in Table 5. The input measurement quantity (the full current sequence of the arrester and dry-type CT collected by timed triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase ); According to Phase Relationship Table 6, the phase difference between the phase currents of different devices of the same type and the current phase difference between devices of the same phase but different types are normal (the deviation between AB / BC / CA and 120° is controlled within the range of (1°, 5°); the deviation between CT_A-CT_B / CT_B-CT_C and 120° is controlled within the range of (0°, 0.2°); the deviation between CT_A-A / CT_B-B / CT_C-C and 4° is controlled within the range of (1°, 5°). It can be judged that the lightning arrester and dry-type CT are not deteriorated.

[0195] Using the capacitor type equipment status detection algorithm, the full current fundamental phase of the non-degraded lightning arrester and dry CT is The optimal three-phase virtual reference voltage phase obtained in stage 1 is used Calculate the phase difference θ between the full current fundamental wave and the voltage fundamental wave MP_3 ,θ CP_3 They are 83.27°, 85.16°, 85.06°, 89.08°, 89.1°, and 88.96°, respectively, and are consistent with the optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT. MP_2 ,θ CP_2 Subtract (85.3°, 85°, 84.95°, 89.13°, 89.08°, 89.15°) to get the phase difference error Δθ MP , Δθ CP They are -2.03°, 0.16°, 0.11°, -0.05°, 0.02°, and -0.19° respectively. The mean square error of the phase difference is used to calculate σ. M_2 , σ C_2 The overall discreteness is represented by 1.02° and 0.09° respectively, and the mean square error of the arrester phase difference error σM_2 Greater than the set threshold σ MT_2 =0.5°, the mean square error of the dry CT phase difference error σ C_2 Less than the set threshold σ CT_2 =0.13, indicating that the arrester has slightly deteriorated in the current set of measured quantities. According to the phase difference error Δθ MP They are -2.03°, 0.16°, and 0.11° respectively. It can be seen that the phase difference error contribution of the A-phase arrester is the largest and Δθ MA If it is greater than 1°, it means that the A phase arrester has slightly deteriorated.

[0196] Using the phase difference θ between the full current fundamental wave and the voltage fundamental wave MP_3 ,θ CP_3 , where the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase arresters A, B and C are 83.27°, 85.16° and 85.06° respectively; the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase dry CTs A, B and C are 89.08°, 89.1° and 88.96° respectively, and the amplitude of the full current fundamental wave in the measurement quantity I MP , I CP , calculate the arrester and dry-type CT resistive current I RMP_3 , I RCP_3 and dielectric loss tanδ MP_3 tanδ CP_3 Among them, the resistive current of the A phase arrester I RMA_3 =49μA and dielectric loss tanσ MA_3 =0.118, which is 0.4 times higher than the normal resistive current of 35μA of the phase A arrester, and 0.39 times higher than the normal dielectric loss of 0.085 of the phase A arrester. Quantitative analysis further verifies that the phase A arrester has slightly deteriorated.

[0197] Table 7 Arrester degradation

[0198]

[0199]

[0200] Table 8 Phase relationship of arrester degradation

[0201]

[0202] The degradation of the arrester in stage 2 is shown in Table 7. The input measurement quantity (the full current sequence of the arrester and dry-type CT collected by timed triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase ); According to phase relationship table 8, the phase difference between the phase currents of different devices of the same type and the current phase difference between devices of the same phase but different types are normal (the deviations of AB / BC / CA from 120° are calculated, where the change in the fundamental phase of the full current of the phase A arrester is greater than 5°; the deviations of CT_A-CT_B / CT_B-CT_C from 120° are controlled within the range of (0°, 0.2°); the deviations of CT_A-A / CT_B-B / CT_C-C from 4° are greater than 5°). It is determined that the phase A arrester has deteriorated, and the full current fundamental sequence of the phase A arrester after this timestamp is separated.

[0203] Using the capacitor type equipment status detection algorithm, the non-degraded B and C phase lightning arresters and the three-phase dry CT full current fundamental phase The optimal three-phase virtual reference voltage phase obtained in stage 1 is used Calculate the phase difference θ between the fundamental current and fundamental voltage of the B and C phase lightning arresters and the three-phase dry CT MP_3 ,θ CP_3 They are 84.84°, 85.05°, 89.05°, 89.15°, and 89.04° respectively, and are consistent with the optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT. MP_2 ,θ CP_2 Subtract (85.3°, 85°, 84.95°, 89.13°, 89.08°, 89.15°) to get the phase difference error Δθ MP , Δθ CP They are -0.16°, 0.1°, -0.08°, 0.07°, and -0.11° respectively. The mean square error of the phase difference is used to calculate σ. M_2 , σ C_2 The overall discreteness is represented by 0.13° and 0.08° respectively, and the mean square error of the arrester phase difference error σ M_2 =0.13° is less than the set threshold σ MT_2 =0.5°, the mean square error of the dry CT phase difference error σ C_2 =0.08° is less than the set threshold σ CT_2 =0.13, indicating that the currently calculated measurements of the B and C phase arresters and three-phase dry-type CTs are normal.

[0204] The phase difference θ between the fundamental current and fundamental voltage of the B and C phase lightning arresters and the three-phase dry CT is calculated. MP_3 ,θ CP_3, where the phase differences between the fundamental current and voltage of the B and C phase arresters are 84.84° and 85.05° respectively; the phase differences between the fundamental current and voltage of the A, B and C three-phase dry CTs are 89.05°, 89.15° and 89.04° respectively, and the amplitude of the fundamental current in the measurement quantity I MP , I CP , calculate the arrester and dry-type CT resistive current I RMP_3 , I RCP_3 and dielectric loss tanδ MP_3 tanδ CP_3 .

[0205] Using the A-phase virtual reference voltage phase Phase with the fundamental wave of the full current of phase A arrester Calculate the phase difference θ between the fundamental wave of the total current and the fundamental wave of the voltage of the A phase arrester MP_4 =78.13°, and further calculation yields the resistive current I of the A-phase arrester. RMA_4 =85μA and dielectric loss tanσ MA_4 =0.21, which is 1.43 times higher than the normal resistive current of 35μA of the phase A arrester, and 1.47 times higher than the normal dielectric loss of 0.085 of the phase A arrester. The quantitative analysis further verifies the degradation of the phase A arrester.

[0206] Table 9 Slight degradation of dry CT

[0207]

[0208] Table 10 Phase relationship of dry CT in case of slight degradation

[0209]

[0210] An example of a slightly degraded dry-type CT in stage 2 is shown in Table 9. The input measurement quantity (the full current sequence of the arrester and dry-type CT collected by timed triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase ); According to the phase relationship table 10, the phase difference between the phase currents of different devices of the same type and the current phase difference between devices of the same phase but different types are normal (the deviation between AB / BC / CA and 120° is controlled within the range of (0°, 1°); the deviation between CT_A-CT_B / CT_B-CT_C and 120° is controlled within the range of (0.2°, 1°), and the deviation between CT_A-A / CT_B-B / CT_C-C and 4° is controlled within the range of (0°, 1°). It can be judged that the lightning arrester and dry-type CT are not deteriorated.

[0211] Using the capacitor type equipment status detection algorithm, the full current fundamental phase of the non-degraded lightning arrester and dry CT is The optimal three-phase virtual reference voltage phase obtained in stage 1 is used Calculate the phase difference θ between the full current fundamental wave and the voltage fundamental wave MP_3 ,θ CP_3 They are 85.36°, 85.11°, 84.9°, 88.64°, 89.11°, and 89.01°, respectively, and are consistent with the optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT. MP_2 ,θ CP_2 Subtract (85.3°, 85°, 84.95°, 89.13°, 89.08°, 89.15°) to get the phase difference error Δθ MP , Δθ CP They are 0.06°, 0.11°, -0.05°, -0.49°, 0.03°, and -0.14° respectively. The mean square error of the phase difference is used to calculate σ. M_2 , σ C_2 The overall discreteness is characterized by 0.06° and 0.22° respectively, and the mean square error of the arrester phase difference error σ M_2 Less than the set threshold σ MT_2 =0.5°, the mean square error of the dry CT phase difference error σ C_2 Greater than the set threshold σ CT_2 =0.13, indicating that the dry CT in the current set of measured quantities has slightly deteriorated. According to the phase difference error Δθ MP They are -0.49°, 0.03°, and -0.14° respectively. It can be seen that the phase difference error contribution of A coherent CT is the largest and Δθ CA If it is greater than 0.2°, it means that the A-coherence CT has slightly deteriorated.

[0212] The phase difference θ between the full current fundamental wave and the voltage fundamental wave is used MP_3 ,θ CP_3 , where the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase arresters A, B and C are 85.36°, 85.11° and 84.9° respectively; the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase dry CTs A, B and C are 88.64°, 89.11° and 89.01° respectively, and the amplitude of the full current fundamental wave in the measurement quantity I MP , I CP , calculate the arrester and dry-type CT resistive current I RMP_3 , I RCP_3 and dielectric loss tanδ MP_3 tanδ CP_3 Among them, the A-phase coherent CT resistive current I RCA_3 =245μA and dielectric loss tanσ CA_3=0.024, which is 0.44 times higher than the resistive current of 170μA of the A-phase coherent CT under normal conditions, and 0.41 times higher than the dielectric loss of 0.017 of the A-phase coherent CT under normal conditions. Quantitative analysis further verifies that the A-phase coherent CT has slightly deteriorated.

[0213] Table 11 Deterioration of dry CT

[0214]

[0215]

[0216] Table 12 Phase relationship of dry CT degradation

[0217]

[0218] The example of dry-type CT degradation in stage 2 is shown in Table 11. The input measurement quantity (the full current sequence of the arrester and dry-type CT collected by timed triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase ); According to phase relationship table 12, the phase difference between the phase currents of different devices of the same type and the current phase difference between devices of the same phase but different types are normal (the calculated deviation of AB / BC / CA from 120° is controlled within the range of (0°, 1°); CT_A-CT_B / CT_B-CT_C deviates from 120°, where the change in the fundamental phase of the full current of the A-phase coherent CT is greater than 1°; CT_A-A / CT_B-B / CT_C-C deviates from 4°, where the change in the fundamental phase difference of the full current of the A-phase lightning arrester and the dry-type CT is greater than 1°. It is judged that the A-coherent CT has deteriorated, and the A-coherent CT full current fundamental sequence after this timestamp is separated.

[0219] Using the capacitor type equipment status detection algorithm, the full current fundamental phase of the non-degraded three-phase lightning arrester and the B and C phase coherent CT is detected. The optimal three-phase virtual reference voltage phase obtained in stage 1 is used Calculate the phase difference θ between the fundamental current and fundamental voltage of the three-phase arrester and the B and C phase coherent CTs MP_3 ,θ CP_3 They are 85.13°, 84.84°, 85.05°, 89.15°, and 89.04° respectively, and are consistent with the optimal solution θ for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT. MP_2 ,θ CP_2 Subtract (85.3°, 85°, 84.95°, 89.13°, 89.08°, 89.15°) to get the phase difference error Δθ MP , Δθ CPThey are -0.17°, 0.16°, -0.1°, 0.07°, and -0.11° respectively. The mean square error of the phase difference is used to calculate σ. M_2 , σ C_2 The overall discreteness is represented by 0.13° and 0.01° respectively, and the mean square error of the arrester phase difference error σ M_2 =0.13° is less than the set threshold σ MT_2 =0.5°, the mean square error of the dry CT phase difference error σ C_2 =0.01° is less than the set threshold σ CT_2 =0.13, indicating that the currently calculated measurements of the three-phase arrester and the B and C phase coherent CTs are normal.

[0220] The phase difference θ between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the B and C phase coherent CT is calculated. MP_3 ,θ CP_3 , where the phase differences between the full current fundamental wave and the voltage fundamental wave of the three-phase arresters A, B and C are 85.13°, 84.84° and 85.05° respectively; the phase differences between the full current fundamental wave and the voltage fundamental wave of the coherent CTs B and C are 89.15° and 89.04° respectively, and the amplitude of the full current fundamental wave in the measured quantity I MP , I CP , calculate the arrester and dry-type CT resistive current I RMP_3 , I RCP_3 and dielectric loss tanδ MP_3 tanδ CP_3 .

[0221] Using the A-phase virtual reference voltage phase Phase of the fundamental wave of the full current of the A-phase coherent CT Calculate the phase difference θ between the full current fundamental wave and voltage fundamental wave of the coherent CT A MP_4 =87.65°, and further calculation yields the A-phase coherent CT resistive current I RCA_4 =422μA and dielectric loss tanσ CA_4 =0.041, which is 1.48 times higher than the resistive current of 170μA of the A-phase coherent CT under normal conditions, and 1.41 times higher than the dielectric loss of 0.017 of the A-phase coherent CT under normal conditions. Quantitative analysis further verifies the degradation of the A-phase coherent CT.

[0222] In summary, the technical solution provided by the embodiment of the present invention obtains the resistive current and dielectric loss of the lightning arrester and dry-type CT under energized conditions through measurement of the same-bus lightning arrester and dry-type CT group and simulation model training, thereby avoiding power outage operations, personnel climbing, safety risks, and shortening the detection cycle. It can realize real-time and reliable evaluation of the insulation status of the lightning arrester and dry-type CT, which is conducive to early, accurate and rapid diagnosis of the insulation status of the lightning arrester and dry-type CT, predicting equipment operation risks, and thus timely eliminating potential fault hazards.

[0223] Figure 10 A schematic diagram of an insulation online monitoring device for capacitor type equipment provided by an embodiment of the present invention is shown in FIG. Figure 10 The insulation online monitoring device includes: an acquisition module 1010, a calculation module 1020 and a determination module 1030.

[0224] The acquisition module 1010 is used to obtain the operating data and standard data of the three-phase lightning arrester and dry-type current transformer on the same bus; the operating data includes the full current fundamental amplitude and phase of the lightning arrester, and the full current fundamental amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental and voltage fundamental of the lightning arrester, and the phase difference between the full current fundamental and voltage fundamental of the dry-type current transformer.

[0225] The calculation module 1020 is used to calculate the optimal solution of the full current fundamental wave and voltage fundamental wave phase difference of the three-phase lightning arrester and dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase based on the operating data, standard data and the preset virtual reference voltage phase initial value, using the optimal solution algorithm model.

[0226] The determination module 1030 is used to establish a capacitive device insulation state detection model based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, and the optimal solution of the three-phase virtual reference voltage phase, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model.

[0227] An online insulation monitoring device for capacitor-type equipment provided by an embodiment of the present invention can execute an online insulation monitoring method for capacitor-type equipment provided by any embodiment of the present invention, and has corresponding functional modules and beneficial effects of the execution method.

[0228] Figure 11A schematic structural diagram of an electronic device for an insulation online monitoring method of a capacitor type device provided in an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0229] like Figure 11 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11. The memory stores a computer program that can be executed by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. Various programs and data required for the operation of the electronic device 10 can also be stored in the RAM 13. The processor 11, ROM 12, and RAM 13 are connected to each other via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0230] Multiple components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0231] The processor 11 can be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a method for online insulation monitoring of capacitor-type equipment.

[0232] In some embodiments, a method for online monitoring of insulation of a capacitor type device may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method for online monitoring of insulation of a capacitor type device described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to execute a method for online monitoring of insulation of a capacitor type device by any other appropriate means (e.g., by means of firmware).

[0233] Various embodiments of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0234] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0235] In the context of the present invention, computer-readable storage media can be tangible media that can contain or store a computer program for use with an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. Computer-readable storage media can include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0236] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0237] A computing system may include clients and servers. The client and server are generally remote from each other and typically interact through a communication network. The client and server relationship arises through computer programs running on the respective computers and having a client-server relationship to each other. The server may be a cloud server.

[0238] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0239] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for online insulation monitoring of a capacitor type device, wherein the capacitor type device includes a lightning arrester and a dry-type current transformer, characterized in that: The insulation online monitoring method comprises: Obtaining operating data and standard data of the lightning arrester and the dry-type current transformer on the same bus three phases; the operating data includes the full current fundamental amplitude and phase of the lightning arrester, and the full current fundamental amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental and the voltage fundamental of the lightning arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer; According to the operating data, the standard data and the preset initial value of the virtual reference voltage phase, the optimal solution algorithm model is used to calculate the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase; Specifically comprising: calculating a first target resistive current according to the full current fundamental amplitude of the arrester, the full current fundamental amplitude of the dry-type current transformer, the phase difference between the full current fundamental and the voltage fundamental of the arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer; Calculating a first target phase difference and a second target phase difference according to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry-type current transformer, and an initial value of a preset virtual reference voltage phase; Calculating a second target resistive current according to the full current fundamental amplitude of the lightning arrester, the full current fundamental amplitude of the dry-type current transformer, the first target phase difference, and the second target phase difference; calculating a resistive current error and a first mean square error of the resistive current error according to the first target resistive current and the second target resistive current; When the first mean square error satisfies a first mean square error threshold, obtaining an optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester and the dry-type current transformer; Calculating the optimal solution for the three-phase virtual reference voltage phase according to the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave; According to the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, and the optimal solution of the three-phase virtual reference voltage phase, a capacitive device insulation state detection model is established to determine the insulation state of the capacitive device through the capacitive device insulation state detection model.

2. The insulation online monitoring method according to claim 1, characterized in that: Before calculating the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer, and the optimal solution of the three-phase virtual reference voltage phase using the optimal solution algorithm model according to the operating data, the standard data and the preset virtual reference voltage phase initial value, the method further includes: Obtaining a first inter-phase current phase difference of similar devices and a second in-phase current phase difference of different devices; judging whether the lightning arrester and the dry-type current transformer in the same group are degraded according to the first inter-phase current phase difference and the second in-phase current phase difference; In the absence of degradation, the steps of calculating the optimal solution of the full current fundamental wave and voltage fundamental wave phase difference of the three-phase lightning arrester and the dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase, are performed based on the operating data, the standard data and the preset virtual reference voltage phase initial value, using the optimal solution algorithm model.

3. The insulation online monitoring method according to claim 1, characterized in that: Calculating the first target resistive current according to the arrester full current fundamental amplitude, the dry-type current transformer full current fundamental amplitude, the arrester full current fundamental and voltage fundamental phase difference, and the dry-type current transformer full current fundamental and voltage fundamental phase difference includes: The first target resistive current is calculated using the following formula: Where, is the first target resistive current of the arrester, is the fundamental amplitude of the arrester's full current, The phase difference between the fundamental wave of the total current and the fundamental wave of the voltage of the arrester; ; is the first target resistive current of the dry-type current transformer, is the full current fundamental amplitude of the dry-type current transformer, It is the phase difference between the full current fundamental wave and voltage fundamental wave of the dry-type current transformer; Calculating the first target phase difference and the second target phase difference according to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry-type current transformer, and the preset virtual reference voltage phase initial value includes: The first target phase difference and the second target phase difference are calculated using the following formula: Where, is the first target phase difference, is the fundamental phase of the arrester's full current, The preset virtual reference voltage phase initial value of the lightning arrester; Where, is the second target phase difference, is the full current fundamental phase of the dry-type current transformer, It is the preset virtual reference voltage phase initial value of the dry-type current transformer; Calculating the second target resistive current according to the full current fundamental amplitude of the arrester, the full current fundamental amplitude of the dry-type current transformer, the first target phase difference, and the second target phase difference includes: The second target resistive current is calculated using the following formula: Where, is the second target resistive current of the arrester; Where, is the second target resistive current of the dry-type current transformer; Calculating a resistive current error and a mean square error of the resistive current error according to the first target resistive current and the second target resistive current includes: The resistive current error is calculated using the following formula: Where, is the resistive current error of the arrester; Where, is the resistive current error of the dry-type current transformer; The mean square error of the resistive current error is calculated using the following formula: Where, is the mean square error of the arrester’s resistive current, for The average value of ; Where, is the mean square error of the resistive current error of the dry-type current transformer, The average value of ; Calculating the optimal solution for the three-phase virtual reference voltage phase according to the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave includes: The following formula is used to calculate the optimal solution of the three-phase virtual reference voltage phase: Where, is the optimal solution for the three-phase virtual reference voltage phase of the lightning arrester, It is the optimal solution for the phase difference between the fundamental wave of the total current and the fundamental wave of the voltage of the arrester; Where, It is the optimal solution for the three-phase virtual reference voltage phase of the dry-type current transformer. It is the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the dry-type current transformer.

4. The insulation online monitoring method according to claim 1, characterized in that: The method further comprises: calculating the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer according to the operating data, the standard data and the preset virtual reference voltage phase initial value, and the optimal solution of the three-phase virtual reference voltage phase using the optimal solution algorithm model. When the first mean square error does not meet a first mean square error threshold, the first target phase difference and the second target phase difference are adjusted, and the three-phase virtual reference voltage phase optimal solution is recalculated until the mean square error threshold is met or the number of loop iterations is reached.

5. The insulation online monitoring method according to claim 1, characterized in that: The step of establishing a capacitive device insulation state detection model based on the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave and the optimal solution for the three-phase virtual reference voltage phase, and determining the insulation state of the capacitive device through the capacitive device insulation state detection model, includes: Using a group synchronous measurement method, based on a preset time interval, the full current fundamental wave amplitude and phase sequence of the lightning arrester and the dry-type current transformer are measured; Obtain the third inter-phase current phase difference of the same type of equipment and the fourth in-phase current phase difference of different types of equipment; judging whether the lightning arrester and the dry-type current transformer in the same group are degraded according to the third inter-phase current phase difference and the fourth in-phase current phase difference; In the absence of degradation, calculating a third target phase difference of the lightning arrester according to the fundamental phase of the total current of the lightning arrester and the optimal solution of the three-phase virtual reference voltage phase; In the absence of degradation, calculating a third target phase difference of the dry-type current transformer according to the full current fundamental phase of the dry-type current transformer and the optimal solution of the three-phase virtual reference voltage phase; Calculating respectively the phase difference error and the second mean square error of the phase difference error between the third target phase difference of the lightning arrester and the dry-type current transformer and the optimal solution of the phase difference of the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the dry-type current transformer; When the second mean square error satisfies a second mean square error threshold, normal and slightly degraded states of the capacitive device are determined, and resistive current and dielectric loss are output.

6. The insulation online monitoring method according to claim 5, characterized in that: After judging whether the lightning arrester and the dry-type current transformer in the same group are degraded according to the third inter-phase current phase difference and the fourth in-phase current phase difference, the method further includes: In the case of degradation, separating the arrester of the degraded phase and the full current fundamental phase of the dry-type current transformer; The fourth target phase difference is calculated based on the optimal solution of the three-phase virtual reference voltage phase and the full current fundamental phase of the lightning arrester and the dry-type current transformer in the degraded phase; and the resistive current and dielectric loss of the degraded phase are output based on the separated full current fundamental amplitude of the lightning arrester and the dry-type current transformer in the degraded phase and the calculated fourth target phase difference.

7. An online insulation monitoring device for a capacitor type device, wherein the capacitor type device comprises a lightning arrester and a dry-type current transformer, characterized in that: The insulation online monitoring device comprises: An acquisition module, the acquisition module is used to obtain the operating data and standard data of the lightning arrester and the dry-type current transformer of the same bus three-phase; the operating data includes the full current fundamental amplitude and phase of the lightning arrester, the full current fundamental amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental and the voltage fundamental of the lightning arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer; A calculation module, the calculation module being configured to calculate, based on the operating data, the standard data, and a preset initial value of the virtual reference voltage phase, an optimal solution algorithm model for calculating the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer, as well as the optimal solution for the three-phase virtual reference voltage phase; Specifically comprising: calculating a first target resistive current according to the full current fundamental amplitude of the arrester, the full current fundamental amplitude of the dry-type current transformer, the phase difference between the full current fundamental and the voltage fundamental of the arrester, and the phase difference between the full current fundamental and the voltage fundamental of the dry-type current transformer; Calculating a first target phase difference and a second target phase difference according to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry-type current transformer, and an initial value of a preset virtual reference voltage phase; Calculating a second target resistive current according to the full current fundamental amplitude of the lightning arrester, the full current fundamental amplitude of the dry-type current transformer, the first target phase difference, and the second target phase difference; Calculating a resistive current error and a mean square error of the resistive current error according to the first target resistive current and the second target resistive current; When the mean square error satisfies a mean square error threshold, obtaining an optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester and the dry-type current transformer; Calculating the optimal solution for the three-phase virtual reference voltage phase according to the optimal solution for the phase difference between the full current fundamental wave and the voltage fundamental wave; A determination module is used to establish a capacitive device insulation state detection model based on the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave, and the optimal solution of the three-phase virtual reference voltage phase, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the insulation online monitoring method according to any one of claims 1 to 6 when executed.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor. The computer program is executed by the at least one processor to enable the at least one processor to perform the insulation online monitoring method according to any one of claims 1 to 6.

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