Insulation online monitoring method and device for capacitive equipment, electronic equipment and storage medium

Abstract

The invention discloses an insulation online monitoring method and device for capacitive equipment, electronic equipment and a storage medium. The method comprises the following steps: acquiring operation data and standard data of a same-bus three-phase lightning arrester and a dry-type current transformer; according to the operation data, the standard data and a preset virtual reference voltage phase initial value, an optimal solution algorithm model is adopted to calculate a phase difference optimal solution of a total current fundamental wave and a voltage fundamental wave of the three-phase lightning arrester and the dry-type current transformer and a phase optimal solution of a three-phase virtual reference voltage; and according to the phase difference optimal solution of the total current fundamental wave and the voltage fundamental wave and the phase optimal solution of the three-phase virtual reference voltage, establishing a capacitive equipment insulation state detection model so as to determine the insulation state of the capacitive equipment through the capacitive equipment insulation state detection model. According to the technical scheme provided by the embodiment of the invention, the problem that the operation defects of the capacitive equipment cannot be found in time due to the fact that a traditional measurement method cannot realize online monitoring is solved.

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] The number of capacitor-type devices in substations accounts for more than 40%. The insulation quality of these capacitor-type devices will affect the reliability of power supply of the power grid, and in serious cases, it will also threaten the safety of other power equipment and personnel in the station.

[0003] Lightning arresters and dry-type current transformers (CT) (hereinafter referred to as "dry-type CT") are the two main capacitive devices in the power system. Their operational safety is related to whether the lightning protection performance and secondary metering level can truly reflect the system operating status and provide accurate signals for the protection device. The resistive current and dielectric loss tanδ of lightning arresters and dry-type CTs can reflect the insulation aging degree of capacitive devices. The insulation status of lightning arresters and dry-type CTs can be evaluated by detecting the resistive current and dielectric loss tanδ.

[0004] The offline detection method for resistive current and dielectric loss tanδ of traditional lightning arresters and dry-type CTs is to power off the equipment at a certain time period and then disassemble it for maintenance. Offline means are not only unable to detect the internal insulation discharge phenomenon of operating lightning arresters and dry-type CTs, but also involve high-altitude operations, which poses a greater risk to personnel safety and long intervals between preventive test cycles, resulting in untimely detection of equipment operation defects. In addition, lightning arresters can also be tested live, but live testing requires taking PT voltage signals. In the context of emphasizing safety, the extraction of secondary voltage from voltage transformers does not conform to the technical development direction of safe and simple live testing of lightning arresters. Dry-type CTs can currently only be tested with power off and not live. In the context of digital operation and maintenance, there is an urgent need for means and methods to measure resistive current and dielectric loss of dry-type CTs online. Summary of the invention

[0005] The present invention provides an insulation online monitoring method, device, electronic device and storage medium for capacitor type equipment, so as to solve the problem that the conventional measurement method cannot realize online monitoring and thus the operation defects of the capacitor type equipment are not discovered in time.

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

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

[0008] According to the operating data, the standard data and the preset virtual reference voltage phase initial value, 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 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 by 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:

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

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

[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, and the optimal solution of the three-phase virtual reference voltage phase are performed according to the operating data, the standard data and the preset virtual reference voltage phase initial value, using the optimal solution algorithm model.

[0014] Optionally, 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 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 includes:

[0015] Calculate 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;

[0016] Calculating a first target phase difference and a second target phase difference according to the full current fundamental phase of the 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 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 the 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 of the three-phase virtual reference voltage phase is calculated according to the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave.

[0021] Optionally, the 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 full current fundamental and voltage fundamental phase difference of the arrester, and the full current fundamental and voltage fundamental phase difference of the dry-type current transformer includes:

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

[0023] In the formula, I RMP is the first target resistive current of the arrester, I MP is the fundamental amplitude of the arrester full current, θ MP It is 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 arrester, the full current fundamental phase of the dry 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] In the formula, θ MP_1 is the first target phase difference, is the fundamental phase of the total current of the lightning arrester, The preset virtual reference voltage phase initial value of the arrester;

[0028] In the formula, 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 comprises:

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

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

[0032] In the formula, 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 ; In the formula, ΔI RMP is the resistive current error of the arrester;

[0036] ΔI RCP =I RCP_1 -I RCP ; In the formula, 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] In the formula, σ M_1 is the mean square error of the resistive current error of the arrester, ΔI RMA , ΔI RMB , ΔI RMC The average value of, P = A, B, C phase;

[0039] In the formula, 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 of the three-phase virtual reference voltage phase according to the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave includes:

[0041] The optimal solution of the three-phase virtual reference voltage phase is calculated using the following formula:

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

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

[0044] Optionally, 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 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 also 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 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.

[0046] Optionally, establishing a capacitive device insulation state detection model 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, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model includes:

[0047] A group synchronous measurement method is adopted to measure and obtain the full current fundamental wave amplitude and phase sequence of the arrester and the dry-type current transformer based on a preset time interval;

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

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

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

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

[0052] In the case that the mean square error satisfies the mean square error threshold, a normal state and a slightly degraded state 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, the arrester and the full current fundamental phase of the dry-type current transformer in the degraded phase are separated;

[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 comprises a lightning arrester and a dry current transformer, and the online insulation monitoring device comprises:

[0057] An acquisition module, the acquisition module is used to acquire the operating data and standard data of the 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 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 voltage fundamental of the arrester, and the full current fundamental and voltage fundamental phase of the dry-type current transformer;

[0058] A calculation module, the calculation module is used to calculate 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 according to the operating data, the standard data and the preset virtual reference voltage phase initial value, using the optimal solution algorithm model;

[0059] A determination module is used to establish a capacitive device insulation state detection model based on the optimal solution of the full current fundamental wave and voltage fundamental wave phase difference 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 described in any embodiment of the present invention when executed.

[0061] According to another aspect of the present invention, an electronic device is provided, the electronic device 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, and 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 described in any embodiment of the present invention.

[0065] The technical solution provided by the embodiment of the present invention implements a solution for measuring the three-phase lightning arrester and dry-type CT group on the same bus 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 bus PT voltage signal on the transmission line side where the lightning arrester and dry-type CT are located, the three-phase virtual reference voltage phase optimal solution is obtained by measuring the total leakage current of the lightning arrester and dry-type CT, and adopting the optimal solution algorithm model training; using the three-phase virtual reference voltage phase optimal solution, the lightning arrester and dry-type CT full current sequence obtained by subsequent timing trigger measurement is analyzed in real time, and the current state 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 sensed, and then its insulation state 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 CTs, which is conducive to early, accurate and rapid diagnosis of the insulation status of lightning arresters and dry CTs, predicting equipment operation risks, and thus eliminating potential faults in a timely manner.

[0066] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily 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 flow chart of an online insulation monitoring method for 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 in an embodiment of the present invention;

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

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

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

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

[0076] Fig. 9 A model diagram of an insulation status detection algorithm for a capacitive device provided in an embodiment of the present invention;

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

[0078] Fig.11 A schematic structural 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 scheme of the present invention, the technical scheme 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 described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0080] It should be noted that the terms "first", "second", etc. in the specification 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 data 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 that are 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 an insulation online monitoring method for a capacitor type device provided by an embodiment of the present invention. This embodiment can be applied to insulation online monitoring of capacitor type devices. The method can be performed by an insulation online monitoring device for capacitor type devices. The insulation online monitoring device can be implemented in the form of hardware and / or software. The insulation online monitoring device can be configured in any electronic device with communication function. The capacitor type device includes a lightning arrester and a dry current transformer. See Figure 1 , the insulation online monitoring method comprises:

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

[0083] Among them, the operating data include 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 include 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 bus 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 team leader, the other five monitoring terminals are triggered through the synchronization antenna to perform synchronous measurement of the full leakage current; the data is uniformly transmitted back to the team leader through wireless communication, and then the team leader uniformly uploads the data to the edge gateway, which centrally manages and analyzes the data reported by the monitoring terminal.

[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 measure synchronously, so as to obtain the amplitude and phase of the full current fundamental wave of the three-phase arrester in the substation; after receiving the synchronous acquisition instruction of the B-phase arrester current monitoring device, the dry-type CT current monitoring device synchronously triggers the measurement to obtain the amplitude and phase of the full current fundamental wave of the three-phase dry-type CT. According to the resistive current and dielectric loss of the arrester and dry-type CT on the same bus detected by the factory or test data, the phase difference θ between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and dry-type CT is obtained. MP ,θCP As a reference standard.

[0087] S120. According to the operation 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 CT, the full current fundamental wave and voltage fundamental wave phase difference θ of the three-phase lightning arrester and dry CT MP ,θ CP , and preset the initial value of the virtual reference voltage phase The optimal solution algorithm model is established, and the measurement data of the arrester and dry-type CT group are iteratively trained to 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, establishing a capacitive device insulation state detection model 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, 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 wave sequence obtained by subsequent timing trigger measurement, and use the phase difference between the phase currents of different devices of the same type and the current phase difference of the same-phase but different-type 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, and accurately calculate the resistive current and dielectric loss parameters of the arrester and dry-type CT in the three situations, so as to perceive 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 a capacitor type device provided in an embodiment of the present invention.

[0092] The technical solution provided by the embodiment of the present invention implements a solution for measuring the three-phase lightning arrester and dry-type CT group on the same bus 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 bus PT voltage signal on the transmission line side where the lightning arrester and dry-type CT are located, the three-phase virtual reference voltage phase optimal solution is obtained by measuring the total leakage current of the lightning arrester and dry-type CT, and adopting the optimal solution algorithm model training; using the three-phase virtual reference voltage phase optimal solution, the lightning arrester and dry-type CT full current sequence obtained by subsequent timing trigger measurement is analyzed in real time, and the current state 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 sensed, and then its insulation state 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 CTs, which is conducive to early, accurate and rapid diagnosis of the insulation status of lightning arresters and dry CTs, predicting equipment operation risks, and thus eliminating potential faults in a timely manner.

[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 was automatically awakened according to the time setting, and other A and C phase lightning arrester current monitoring devices and A, B, C three-phase dry-type CT current monitoring devices were triggered by pulse signals to perform full current synchronous measurement. After taking the average value, the accurate full current fundamental amplitude and phase were obtained. Among them, I MP , is the amplitude and phase of the fundamental wave of the total current of the arrester; I CP , It is the amplitude and phase of the full current fundamental wave of the dry CT (P = A, B, C phase).

[0095] Step 2: Model training: Based on the factory or test data of the same busbar three-phase 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 of the full current fundamental wave and voltage fundamental wave of the three-phase lightning arrester and dry-type CT in the ideal state 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) Measurement 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: According to the factory or test data of the same bus three-phase arrester, dry CT resistive current and dielectric loss, the phase difference θ of the total current fundamental wave and 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) Introduction: 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. According to the 120° phase difference of the three-phase voltage, 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 criterion for degradation, 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 arrester and dry CT resistive current error, the mean square error threshold σ of the arrester and dry CT resistive current error 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 current phase difference between the same-phase devices of different types (the second same-phase current phase difference) to determine whether the three-phase arresters and dry-type CTs in the same group are degraded;

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

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

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

[0107] The current phase difference between the same-phase and different-type devices (the second same-phase current phase difference) is specifically explained as follows:

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

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

[0112] In the formula, IRMP is the first target resistive current of the arrester, I MP is the fundamental amplitude of the arrester full current, θ MP It is 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] According to the full current fundamental phase of the lightning arrester, the full current fundamental phase of the dry current transformer and the initial value of the preset virtual reference voltage phase, the first target phase difference and the second target phase difference are calculated.

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

[0116] In the formula, θ MP_1 is the first target phase difference, is the fundamental phase of the total current of the lightning arrester, The preset virtual reference voltage phase initial value of the arrester;

[0117] In the formula, 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.

[0118] The second target resistive current is calculated 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.

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

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

[0121] In the formula, 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 ; In the formula, ΔI RMP is the resistive current error of the arrester;

[0125] ΔI RCP =I RCP_1 -I RCP ; In the formula, 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] In the formula, σ M_1 is the mean square error of the resistive current error of the arrester, ΔI RMA , ΔI RMB , ΔI RMC The average value of, P = A, B, C phase;

[0128] In the formula, 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 Average value, P = A, B, C phase.

[0129] Determine whether the mean square error meets the mean square error threshold σ of the arrester and dry 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 of the full current fundamental wave and 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] In the formula, It is the optimal solution for the three-phase virtual reference voltage phase of the arrester;

[0134] In the formula, 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 of the phase difference between the full current fundamental wave and voltage fundamental wave of the lightning arrester and dry CT, θ MP_2 ,θ CP_2 , calculate the resistive current I of the three-phase arrester and dry-type CT RMP_2 ,I RCP_2 (P = A, B, C phase);

[0136]

[0137] Optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester and dry CT θ 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] Exemplarily, Table 1 Finding the optimal solution (stage 1)

[0141]

[0142]

[0143] Table 2 Phase relationship (stage 1)

[0144]

[0145] The specific stage 1 is shown in Table 1, and the target quantity, measured quantity (average of 10 repeated measurements) and introduced quantity are input; according to the phase relationship table 2, it can be seen that the phase difference between the phase currents of different devices of the same type and the current phase difference between the same-phase and different-type devices are normal (AB / BC / CA / CT_A-CT_B / CT_B-CT_C / CT_C-CT_A differ by about 120°, and CT_A-A / CT_B-B / CT_C-C differ by about 4°), and it is judged that the lightning arrester and dry CT are normal.

[0146] Using the optimal solution algorithm model, through cyclic iteration, it is found that the mean square error of the arrester and dry CT resistive current error converges to 1.2μA and 5.6μA, which are set as the mean square error threshold σ of the arrester and dry CT resistive current error. 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 wave of the full current and the fundamental wave of the 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 of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase lightning arrester and the dry CT θ P_2 , calculate the optimal A, B and C three-phase virtual reference voltage They are 164.28°, 44.28° and 284.28° respectively, which meet 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 fundamental wave of the three-phase arrester and dry-type CT full current 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 a 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, 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 wake up according to the time setting, and trigger other A, 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, and obtain the dynamic A, B, C three-phase lightning arrester 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 total current of the arrester; I CP , It is the amplitude and phase of the full current fundamental wave of the dry CT (P = A, B, C phase). Fig. 9 , Fig. 9 A model diagram of the capacitance device insulation status detection algorithm provided in an embodiment of the present invention.

[0152] Obtain the third phase-to-phase current phase difference of different same-type devices and the fourth same-phase current phase difference of same-phase but different-type 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 phase of the lightning arrester and dry-type current transformer and the three-phase virtual reference voltage phase.

[0153] Calculate the phase difference error and the mean square error of the phase difference error between the third target phase difference and the optimal solution of the phase difference of 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 the mean square error threshold, the normal and slightly degraded states of the capacitive device are determined, and the resistive current and dielectric loss are output.

[0155] In the presence of degradation, the degraded phase 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 degraded phase arrester and the full current fundamental phase of the dry-type current transformer, and the resistive current and dielectric loss of the degraded phase are output based on the full current fundamental amplitude of the arrester and the dry-type current transformer of the separated degraded phase and the calculated fourth target phase difference.

[0156] Specifically, ① Input quantity:

[0157] a) Measurement 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) Introduction: The optimal three-phase virtual reference voltage phase obtained in stage 1 is called And the corresponding optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave of the dry CT is θ MP_2 ,θ CP_2 , the arrester and dry-type CT resistive current is doubled as the deterioration criterion, 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 of the current between different devices of the same type and the current phase difference of the same-phase but different-type devices to determine whether the arresters and dry-type CTs of the same group collected at different timestamps have deteriorated; (the deterioration criterion is consistent with the specific explanation of the phase difference of the current between different devices of the same type and the current phase difference of the same-phase but different-type devices in the same phase in stage 1--->step 2②process calculation amount--->a), and will not be repeated 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 arrester or dry-type CT deteriorates after a certain timestamp) 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 Calculate, directly execute step (h), and vice versa;

[0162] c) The fundamental phase of the total current of the arrester and dry-type CT measured by timing triggering 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 Average value, P = A, B, C phase.

[0170] f) Determine whether the mean square error is less than the mean square error threshold σ of the phase difference error of the arrester and dry CT MT_2 , σ CT_2 If yes, then the current insulation state of the arrester or dry-type CT is considered normal; if no, then the error Δθ of the phase difference between the fundamental wave of the full current and the fundamental wave of the 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 that has experienced slight degradation.

[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 CT resistive current I RMP_3 ,I RCP_3 (P = A, B, C phase);

[0173]

[0174] Using the phase difference θ between the full current fundamental wave and the voltage fundamental wave at the current moment MP_3 ,θCP_3 , and the dielectric loss angle δ MP_3 ,δ CP_3 The dielectric loss tanδ can be calculated by the complementary 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 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 deterioration arrester and the full current fundamental wave of the dry CT The fourth target phase difference θ between the fundamental current wave and the fundamental voltage wave of the A-phase degraded arrester and the dry-type CT is calculated. MP_4 ,θ CP_4 Sequence, finally calculate the resistive current I of the A phase deterioration arrester and dry CT RMP_4 ,I RCP_4 Sequence (P = A phase)

[0179]

[0180] The phase difference θ between the fundamental current wave and the fundamental voltage 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 by using the complementary relationship. MP_4 , tanδ CP_4 sequence (P = A phase).

[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 CT collected by timing triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase According to the phase relationship table 4, the phase difference between the phase currents of different devices of the same type and the current phase difference between the same-phase and different-type devices are normal (AB / BC / CA and 120° deviation are controlled within the range of (0°, 1°); CT_A-CT_B / CT_B-CT_C and 120° deviation are controlled within the range of (0°, 0.2°), and CT_A-A / CT_B-B / CT_C-C and 4° deviation are controlled within the range of (0°, 1°). It can be judged that the arrester and dry-type CT are not degraded.

[0188] Using the capacitor-type equipment status detection algorithm, the fundamental phase of the full current of the non-degraded lightning arrester and dry-type 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 of the phase difference of the full current fundamental wave and voltage fundamental wave of the three-phase lightning arrester and dry-type CT θ 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 0.13° and 0.08° respectively, which is less than the set threshold. σ CT_2 =0.13, indicating that the currently calculated set of measurements is normal.

[0189] 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 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 measured quantity IMP ,I CP , calculate the arrester and dry CT resistive current I RMP_3 ,I RCP_3 and dielectric loss tanδ MP_3 , tanδ CP_3 .

[0190] Table 5 Slight deterioration of arrester

[0191]

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

[0193]

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

[0195] Using the capacitor-type equipment status detection algorithm, the fundamental phase of the full current of the non-degraded lightning arrester and dry-type 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 of the phase difference of the full current fundamental wave and voltage fundamental wave of the three-phase arrester and dry-type CT θ 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. 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 measured quantity I MP ,I CP , calculate the arrester and dry 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 resistive current of 35μA of the A-phase arrester under normal conditions, and 0.39 times higher than the dielectric loss of 0.085 of the A-phase arrester under normal conditions. Quantitative analysis further verifies that the A-phase 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 CT collected by timing triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase ); According to the phase relationship table 8, the phase difference of the phase current of different devices of the same type and the current phase difference of the same-phase but different types of devices are normal (the deviation of AB / BC / CA from 120° is calculated, and the change of the fundamental phase of the full current of the A-phase lightning arrester is greater than 5°; the deviation of CT_A-CT_B / CT_B-CT_C from 120° is controlled within the range of (0°, 0.2°); the deviation of CT_A-A / CT_B-B / CT_C-C from 4°, and the change of the full current fundamental phase difference of the A-phase lightning arrester and the dry-type CT is greater than 5°), it is judged that the A-phase lightning arrester has deteriorated, and the full current fundamental sequence of the A-phase lightning 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 Calculate the phase difference θ between the fundamental wave of the total current and the fundamental wave of the 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 of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry CT θ 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 characterized 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 CT are normal.

[0204] The phase difference θ between the fundamental wave of the full current and the fundamental wave of the voltage of the B and C phase lightning arresters and the three-phase dry CT is MP_3 ,θ CP_3, where the phase differences between the fundamental current and fundamental voltage of the B and C phase arresters are 84.84° and 85.05° respectively; the phase differences between the fundamental current and fundamental 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 measured quantity I MP ,I CP , calculate the arrester and dry 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 total current of the A-phase 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 A phase arrester resistive current I RMA_4 =85μA and dielectric loss tanσ MA_4 =0.21, which is 1.43 times higher than the resistive current of 35μA of the A-phase arrester under normal conditions, and 1.47 times higher than the dielectric loss of 0.085 of the A-phase arrester under normal conditions. The quantitative analysis further verifies the degradation of the A-phase 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 the slight degradation of 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 timing 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 the same-phase and different-type devices are normal (AB / BC / CA and 120° deviation are controlled within the range of (0°, 1°); CT_A-CT_B / CT_B-CT_C and 120° deviation are controlled within the range of (0.2°, 1°), and CT_A-A / CT_B-B / CT_C-C and 4° deviation are controlled within the range of (0°, 1°). It can be judged that the arrester and dry-type CT are not degraded.

[0211] Using the capacitor-type equipment status detection algorithm, the fundamental phase of the full current of the non-degraded lightning arrester and dry-type CT is The optimal three-phase virtual reference voltage phase obtained in stage 1 is 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 of the phase difference of the full current fundamental wave and voltage fundamental wave of the three-phase lightning arrester and dry-type CT θ 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-coherent CT has slightly deteriorated.

[0212] 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 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 measured quantity I MP ,I CP , calculate the arrester and dry 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 normal A-phase coherent CT resistive current of 170μA, and 0.41 times higher than the normal A-phase coherent CT dielectric loss of 0.017. 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 timing triggering) and the introduced quantity (the optimal three-phase virtual reference voltage phase ); According to the phase relationship table 12, the phase difference between the phase currents of different devices of the same type and the current phase difference of the same-phase but different types of devices 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°, and 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°, and the change in the fundamental phase difference of the full current of the A-phase lightning arrester and the dry CT is greater than 1°. It is judged that the A-phase coherent CT has deteriorated, and the A-phase coherent CT full current fundamental sequence after this timestamp is separated.

[0219] Using the capacitor-type equipment status detection algorithm, the fundamental phase of the full current of the 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 wave of the total current and the fundamental wave of the voltage of the three-phase arrester and the B and C phase coherent CT 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 of the phase difference between the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type CT θ 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 arrester and the B and C phase coherent CT is 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 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 full current fundamental wave 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 A-phase coherent CT resistive current of 170μA under normal conditions, and 1.41 times higher than the A-phase coherent CT dielectric loss of 0.017 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 arrester and dry-type CT under energized conditions through the measurement of the same-bus arrester and dry-type CT group and the training of the simulation model, 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 arrester and dry-type CT, which is conducive to early, accurate and rapid diagnosis of the insulation status of the arrester and dry-type CT, predicting the equipment operation risk, and thus timely eliminating potential fault hazards.

[0223] Fig.10 A schematic diagram of an insulation online monitoring device for a capacitor type device provided by an embodiment of the present invention, see Fig.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 wave amplitude and phase of the lightning arrester, and the full current fundamental wave amplitude and phase of the dry-type current transformer; the standard data includes the phase difference between the full current fundamental wave and the voltage fundamental wave of the lightning arrester, and the phase difference between the full current fundamental wave and the voltage fundamental wave of the dry-type current transformer.

[0225] The calculation module 1020 is used to calculate the optimal solution of the full current fundamental and voltage fundamental 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 functional modules and beneficial effects corresponding to the execution method.

[0228] Fig.11A schematic diagram of the structure of an electronic device for an insulation online monitoring method of a capacitor type device provided by an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, 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 Fig.11 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and 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 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0230] A number of 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 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 through a computer network such as the Internet and / or various telecommunication networks.

[0231] The processor 11 may be a variety of general and / or special processing components 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 dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as an insulation online monitoring method for a capacitor-type device.

[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 implementations of the systems and techniques described above 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), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including 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, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

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

[0236] To provide interaction with a user, the systems and techniques described herein may 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 a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0237] A computing system may include clients and servers. Clients and servers are generally remote from each other and typically interact through a communication network. The relationship of client and server is generated by computer programs running on 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 processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0239] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for online insulation monitoring of a capacitor type device, wherein the capacitor type device comprises a lightning arrester and a dry current transformer, characterized in that: The insulation online monitoring method comprises: Obtaining the operating data and standard data of the arrester and the dry-type current transformer of the same bus three-phase; the operating data includes the full current fundamental wave amplitude and phase of the arrester, the full current fundamental wave amplitude and phase of the dry-type current transformer; the standard data includes the full current fundamental wave and voltage fundamental wave phase difference of the arrester, the full current fundamental wave and voltage fundamental wave phase difference of the dry-type current transformer; According to the operating data, the standard data and the preset virtual reference voltage phase initial value, 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 the dry-type current transformer, as well as the optimal solution of the three-phase virtual reference voltage phase; 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 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 arrester and the dry-type current transformer, and the optimal solution of the three-phase virtual reference voltage phase according to the operating data, the standard data and the preset virtual reference voltage phase initial value, the method further includes: Obtaining a first interphase current phase difference of the same type of equipment and a second in-phase current phase difference of different types of equipment; According to the first interphase current phase difference and the second in-phase current phase difference, judging whether the lightning arrester and the dry-type current transformer in the same group are degraded; 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, and the optimal solution of the three-phase virtual reference voltage phase are performed according to 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: 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 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 includes: Calculate 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 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 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 the 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; The optimal solution of the three-phase virtual reference voltage phase is calculated according to the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave.

4. The insulation online monitoring method according to claim 3 is characterized in that: The 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 comprises: The first target resistive current is calculated using the following formula: In the formula, I RMP is the first target resistive current of the arrester, I MP is the fundamental amplitude of the arrester full current, θ MP It is the phase difference between the fundamental wave of the total current and the fundamental wave of the voltage of the arrester; 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 current transformer; Calculating the first target phase difference and the second target phase difference according to the full current fundamental phase of the arrester, the full current fundamental phase of the dry 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: In the formula, θ MP_1 is the first target phase difference, is the fundamental phase of the total current of the lightning arrester, The preset virtual reference voltage phase initial value of the arrester; In the formula, 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; 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 comprises: The second target resistive current is calculated using the following formula: In the formula, I RMP_1 is the second target resistive current of the arrester; In the formula, I RCP_1 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: ΔI RMP =I RMP_1 -I RMP ; In the formula, ΔI RMP is the resistive current error of the arrester; ΔI RCP =I RCP_1 -I RCP ; In the formula, ΔI RCP 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: In the formula, σ M_1 is the mean square error of the resistive current error of the arrester, ΔI RMA , ΔI RMB , ΔI RMC The average value of, P = A, B, C phase; In the formula, 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; Calculating the optimal solution of the three-phase virtual reference voltage phase according to the optimal solution of the phase difference between the full current fundamental wave and the voltage fundamental wave includes: The optimal solution of the three-phase virtual reference voltage phase is calculated using the following formula: In the formula, It is the optimal solution for the three-phase virtual reference voltage phase of the arrester; In the formula, It is the optimal solution for the three-phase virtual reference voltage phase of dry-type current transformer.

5. The insulation online monitoring method according to claim 2, characterized in that: 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 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 also includes: 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 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.

6. The insulation online monitoring method according to claim 1, characterized in that: The step of establishing a capacitive device insulation state detection model 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, so as to determine the insulation state of the capacitive device through the capacitive device insulation state detection model, comprises: A group synchronous measurement method is adopted to measure and obtain the full current fundamental wave amplitude and phase sequence of the arrester and the dry-type current transformer based on a preset time interval; Obtain the third interphase current phase difference of the same type of equipment and the fourth in-phase current phase difference of different types of equipment; According to the third interphase current phase difference and the fourth in-phase current phase difference, judging whether the lightning arrester and the dry-type current transformer in the same group are degraded; In the absence of degradation, calculating a third target phase difference according to the optimal solution of the arrester, the full current fundamental phase of the dry-type current transformer and the three-phase virtual reference voltage phase; Calculate the phase difference error and the mean square error of the phase difference error between the third target phase difference and the optimal solution of the phase difference of the full current fundamental wave and the voltage fundamental wave of the three-phase arrester and the dry-type current transformer; In the case that the mean square error satisfies the mean square error threshold, a normal state and a slightly degraded state of the capacitive device are determined, and resistive current and dielectric loss are output.

7. The insulation online monitoring method according to claim 6, 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, the arrester and the full current fundamental phase of the dry-type current transformer in the degraded phase 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 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.

8. An online insulation monitoring device for a capacitor type device, the capacitor type device comprising a lightning arrester and a dry current transformer, characterized in that: The insulation online monitoring device comprises: An acquisition module, the acquisition module is used to acquire the operating data and standard data of the 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 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 voltage fundamental of the arrester, and the full current fundamental and voltage fundamental phase of the dry-type current transformer; A calculation module, the calculation module is used to calculate 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 according to the operating data, the standard data and the preset virtual reference voltage phase initial value, using the optimal solution algorithm model; 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.

9. 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 7 when executed.

10. 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 executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the online insulation monitoring method according to any one of claims 1 to 7.

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