A high-voltage switch cabinet bus insulation on-line detection method and device

Abstract

The application discloses a kind of high-voltage switchgear busbar insulation on-line detection method and device, it is related to the field of insulation detection technology, including, the busbar topology state information of each phase busbar in high-voltage switchgear is collected, is divided into multiple busbar insulation sections, and is configured high resistance isolation coupling branch, forms busbar partition constraint information;According to path admittance observation information, apparent insulation admittance is jointly inverted, obtains equivalent insulation admittance, and equivalent insulation admittance and path insulation characteristic information are classified according to stable response range, identify insulation deterioration characteristic information, and carry out associated output, form busbar insulation detection state.The application is constructed by section path inversion relationship based on the relationship of path through section, and the inversion quantity to be corrected of each busbar insulation section is iteratively corrected with apparent insulation admittance as path observation value, realizes the decoupling attribution of the path response across multiple busbar insulation sections to section equivalent insulation admittance.

Description

Technical Field

[0001] This invention relates to the field of insulation testing technology, and in particular to an online testing method and device for the insulation of busbars in high-voltage switchgear. Background Technology

[0002] As a key complete set of equipment in the power distribution network, high-voltage switchgear's busbars are subjected to long-term operating factors such as power frequency voltage, electric field stress, temperature rise, humidity and heat, and pollution. The insulation status of the busbars to ground and between phases needs to be continuously monitored under uninterrupted power supply conditions. Existing online insulation monitoring usually sets up an isolation coupling interface on the low-voltage side of the cabinet. By applying a small detection excitation, collecting the circuit response, and converting the insulation parameters, the trend of changes in the busbar circuit insulation can be monitored. For scenarios involving busbar segmentation, phase connection, and changes in operating topology, the relevant detection devices will also organize the detection channels in combination with the switch status and branch connection relationship to maintain the safety and continuity of the detection process under energized operation.

[0003] In operation scenarios where a multiphase busbar is continuously connected by multiple insulation sections and the detection path traverses different sections, the detection excitation and response signals are simultaneously affected by power frequency phase changes, interphase coupling relationships, and path superposition effects. If the detection signal is sent only according to a fixed time period and the insulation state is directly characterized by a single path response, the admittance contribution of different path sections is easily mixed into the same observation, making it difficult to stably separate section-level insulation changes from the path response. This limits the accuracy of online detection in identifying the location of local insulation degradation and its continuous evolution. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides an online detection method for busbar insulation in high-voltage switchgear to solve the problem of difficulty in accurately separating and locating the admittance of multi-section busbar insulation during the energized operation of high-voltage switchgear.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides an online detection method for busbar insulation in a high-voltage switchgear, comprising: collecting busbar topology status information of each phase busbar in the high-voltage switchgear, dividing it into multiple busbar insulation sections, and configuring high-impedance isolation coupling branches to form busbar partition constraint information; using the busbar partition constraint information, selecting power frequency phase intervals according to the relative-to-ground detection path and phase-to-phase detection path corresponding to the target busbar insulation section, and performing power frequency phase window control on the relative-to-ground detection path and phase-to-phase detection path to form a phase window routing instruction; based on the phase window routing instruction, connecting the coded signal channel and the sampling channel on the low-voltage side, and sending low-energy perturbations with path coding identifiers through the high-impedance isolation coupling branches. The signal is time-stamped and path-marked to form coded path response information. Coding synchronization response separation is performed on the coded path response information to obtain the effective response components corresponding to the path to be detected. The apparent insulation admittance of the path to be detected is calculated, and path insulation feature information is extracted. Simultaneously, the path number to be detected is associated with the path traversal segment relationship in the busbar partition constraint information to form path admittance observation information. Based on the path admittance observation information, the apparent insulation admittance is jointly inverted to obtain the equivalent insulation admittance. The equivalent insulation admittance and path insulation feature information are classified according to the stable response range to identify insulation degradation feature information and perform associated output to form the busbar insulation detection status.

[0007] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for forming busbar partition constraint information are as follows: Based on the bus topology status information, the continuous connection relationship and insulation boundary position of each phase bus are identified. Multiple bus insulation sections are divided along the continuous connection relationship of each phase bus, and the section identifier, phase identifier and adjacency relationship of each bus insulation section are registered to form bus insulation section positioning information. Based on the busbar insulation section location information, high-resistance isolation coupling branches are deployed at the detection locations corresponding to each busbar insulation section. A relative-to-ground detection path and a phase-to-phase detection path are constructed around each high-resistance isolation coupling branch. The busbar insulation sections traversed by each relative-to-ground detection path and phase-to-phase detection path are determined, forming the relationship between the path traversed sections. The busbar insulation sections, high-resistance isolation coupling branches, relative-to-ground detection paths, phase-to-phase detection paths, and the relationship between the path traversed sections are then registered accordingly to form busbar zoning constraint information.

[0008] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for screening the power frequency phase interval are as follows: For the relative-to-ground detection path in the busbar partition constraint information, the power frequency voltage of the corresponding phase is used as the phase reference. For the phase-to-phase detection path, the power frequency voltage between the corresponding phases is used as the phase reference. The current power frequency cycle is divided into continuous phase segments according to the power frequency reference relationship of each detection path to form path phase segmentation information. Based on the path phase segmentation information, the running response within a continuous phase segment is matched with the detection release criteria of the corresponding detection path. Continuous phase segments that meet the detection release criteria are merged into candidate power frequency phase intervals, while continuous phase segments that do not meet the detection release criteria are excluded. The candidate power frequency phase intervals are then filtered by duration according to the transmission duration of the low-energy perturbation signal and the response acquisition duration to form power frequency phase intervals.

[0009] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for forming the phase window routing command are as follows: The power frequency phase interval is window-bound with the corresponding detection path, and the detection time slots of the relative ground detection path and the phase-to-phase detection path are arranged according to the time order of each power frequency phase interval. For detection paths with overlapping power frequency phase intervals, one is selected for arrangement according to the detection priority of the bus insulation section associated with the path. The detection paths that are not arranged are excluded from the current detection time slot arrangement to form path window arrangement information. Based on the path window arrangement information, the detection path arranged by the detection time slot is determined as the path to be detected, and the path to be detected, the corresponding power frequency phase interval, the path code identifier and the detection time slot are associated and encapsulated to form a phase window routing instruction.

[0010] In a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for forming the coded path response information are as follows: According to the phase window routing instruction, within the corresponding detection time slot, the path coding identifier is loaded onto the low-energy perturbation signal, and the coding signal channel and sampling channel corresponding to the path to be detected are connected on the low-voltage side. The coding signal channel and sampling channel are connected to the path to be detected through the corresponding high-impedance isolation coupling branch. Within the power frequency phase interval corresponding to the path to be detected, a low-energy perturbation signal is sent to the path to be detected through the coded signal channel and the corresponding high-impedance isolation coupling branch, and the response signal of the path to be detected is collected through the sampling channel. The transmission time stamp of the low-energy perturbation signal and the sampling time stamp of the response signal are registered accordingly to form a path response record. Based on the path encoding identifier, transmission time stamp, and sampling time stamp, the path response records are time-stamped and then associated with the time-stamped path response records to the path to be detected, thus forming encoded path response information.

[0011] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for calculating the apparent insulation admittance of the path to be detected are as follows: Based on the path encoding identifier, transmission time stamp, and sampling time stamp in the encoded path response information, the path response record is encoded and located, and the response segments corresponding to the low-energy perturbation signal are time-aligned according to the transmission time stamp and sampling time stamp to form an encoded synchronous response record. The corresponding coding template is determined based on the path coding identifier. The coding synchronization response record is divided into multiple response segments according to the coding period of the low-energy perturbation signal. Temporal alignment and coding correlation calculation are performed on each response segment and the coding template to obtain the corresponding coding correlation quantity. Matching status identification is performed on each response segment according to the coding correlation quantity. Response segments whose coding correlation quantity meets the matching condition are retained, and response segments that do not meet the matching condition are excluded. The retained response segments are accumulated with the same coding to obtain the effective response component corresponding to the path to be detected. The apparent insulation admittance of the path to be detected is calculated based on the amplitude and phase relationships between the excitation voltage corresponding to the low-energy perturbation signal and the response current corresponding to the effective response component.

[0012] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for forming path admittance observation information are as follows: According to the path number to be tested, the apparent insulation admittance is associated with the corresponding test time marker, and the apparent insulation admittance of the same path to be tested is sequentially arranged according to the test time marker within the continuous test time slot to form a path admittance observation sequence; The path admittance observation sequence is divided into continuous observation segments. Differential calculation is performed on adjacent apparent insulation admittances within each continuous observation segment. Interval merging and coding registration are performed according to the continuous distribution of differential calculation values. The coded registration content is associated with the path number to be detected to form path insulation feature information. Based on the path number to be tested, the corresponding path segment relationship is located in the busbar partition constraint information. The path admittance observation sequence, path insulation feature information and path number to be tested are associated and encapsulated according to the path segment relationship to form path admittance observation information.

[0013] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for obtaining the equivalent insulation admittance are as follows: The path admittance observation sequence corresponding to each path to be tested is collected into the bus insulation section it passes through, and the path association registration is performed on the paths to be tested that pass through the same bus insulation section to form the segment path observation relationship. The equivalent insulation admittance of each busbar insulation section is used as the quantity to be inverted, and the apparent insulation admittance in the path admittance observation sequence is used as the path observation value. According to the busbar insulation section through which each path to be detected passes, the path observation value and the corresponding quantity to be inverted are established to form the section path inversion relationship. The inversion admittance corresponding to each path to be detected is calculated based on the inversion relationship of the segment path. The inversion admittance and the apparent insulation admittance are calculated as residuals. The inversion quantities to be inverted in the relevant bus insulation sections are iteratively corrected using the residual calculation values. The inversion quantities that meet the residual convergence requirements are determined as the equivalent insulation admittance of the corresponding bus insulation sections. The inversion quantities that do not meet the residual convergence requirements are taken as the correction quantities. The corresponding inversion admittance is recalculated and iteratively corrected until the residual convergence requirements are met, and the equivalent insulation admittance is obtained.

[0014] As a preferred embodiment of the online detection method for busbar insulation of high-voltage switchgear according to the present invention, the specific steps for forming the busbar insulation detection state are as follows: The equivalent insulation admittance and associated path insulation characteristic information of each bus insulation section are arranged according to the detection time scale and matched with the stable response range of the bus insulation section. The equivalent insulation admittance and path insulation characteristic information that fall within the stable response range are marked as stable records, and the equivalent insulation admittance and path insulation characteristic information that deviate from the stable response range are marked as deviation records. Along the detection timescale, the deviation records of the same busbar insulation section are spliced ​​into continuous segments. The change boundaries corresponding to the continuous deviation records are extracted to form insulation degradation characteristic information. The stable records and insulation degradation characteristic information are loaded into the detection records of the corresponding busbar insulation section to form the busbar insulation detection status.

[0015] Secondly, the present invention provides an online detection device for the insulation of a high-voltage switchgear busbar, comprising: The metal casing serves as the supporting base for this device, and is used to fix and install the high-voltage A-phase current-limiting resistor, the high-voltage B-phase current-limiting resistor, and the high-voltage C-phase current-limiting resistor, forming an equipotential safety protection cavity for the entire machine. The grounding terminal is located on the side of the metal casing to protect the internal electrical components from damage caused by overvoltage. The high-voltage A-phase current-limiting resistor, high-voltage B-phase current-limiting resistor, and high-voltage C-phase current-limiting resistor adopt a silicone rubber multi-layer umbrella skirt integrated solid-sealing structure to maintain stable resistance parameters under high and low temperature and humid conditions, ensuring the comparability of multiple test results. Copper connectors have excellent conductivity and can be firmly locked to the high-voltage busbar terminals to prevent measurement data distortion caused by poor wiring contact.

[0016] The beneficial effects of this invention are as follows: by constructing the segment path inversion relationship based on the relationship of the path traversed, and iteratively correcting the inversion quantities of each bus insulation segment using the apparent insulation admittance as the path observation value, the path response traversing multiple bus insulation segments is decoupled and assigned to the equivalent insulation admittance of the segment. This enables the path insulation feature information to be accurately associated with the corresponding segment, which is used to continuously identify the deviation of the local insulation state from the boundary and the trend of deterioration evolution, thereby improving the localization and stability of the live detection state. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of an online testing method for the insulation of busbars in high-voltage switchgear.

[0019] Figure 2 This is a schematic diagram of an online insulation testing device for high-voltage switchgear busbars.

[0020] Figure 3 A flowchart for the phase window routing instruction.

[0021] Figure 4 This is a flowchart illustrating the busbar insulation detection status.

[0022] Explanation of reference numerals in the attached diagram: 1. Metal casing; 2. Grounding terminal; 3. High-voltage A-phase current-limiting resistor; 4. High-voltage B-phase current-limiting resistor; 5. High-voltage C-phase current-limiting resistor; 6. Copper connector. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0026] Reference Figures 1-4 As one embodiment of the present invention, this embodiment provides an online detection method for the insulation of a high-voltage switchgear busbar, comprising the following steps: S1: Collect bus topology status information of each phase bus in the high-voltage switchgear, divide it into multiple bus insulation sections, and configure high-resistance isolation coupling branches to form bus partition constraint information.

[0027] S1.1: Based on the bus topology status information, identify the continuous connection relationship and insulation boundary position of each phase bus, divide multiple bus insulation sections along the continuous connection relationship of each phase bus, and register the section identifier, phase identifier and adjacency relationship of each bus insulation section to form bus insulation section positioning information.

[0028] It should be noted that the bus topology status information includes the identification and phase affiliation of the bus connection nodes, the electrical connection relationship between the connection nodes, the conduction or isolation status of each connection location, and the insulation boundary location used to divide the bus insulation sections. Furthermore, in the bus topology status information, bus connection nodes, inter-node connection records, and insulation isolation positions are organized according to phase, and the connection nodes of the same phase bus are sorted according to the electrical connection order; the insulation isolation position, bus connection endpoint, and connection record interruption position are used as the section boundary position, and the bus connection nodes and inter-node connection records between adjacent section boundary positions are grouped into the same bus insulation section; a section identifier is assigned to each bus insulation section, the corresponding phase is registered, and an adjacency mark is established for bus insulation sections that share a section boundary position or have a direct connection relationship. The section identifier, the corresponding phase, and the adjacency mark are stored accordingly to form the bus insulation section positioning information.

[0029] S1.2: Based on the busbar insulation section location information, high-resistance isolation coupling branches are deployed at the detection locations corresponding to each busbar insulation section. A relative-to-ground detection path and a phase-to-phase detection path are constructed around each high-resistance isolation coupling branch. The busbar insulation sections traversed by each relative-to-ground detection path and phase-to-phase detection path are determined, forming the relationship between the path traversed sections. The busbar insulation sections, high-resistance isolation coupling branches, relative-to-ground detection paths, phase-to-phase detection paths, and the relationship between the path traversed sections are registered accordingly to form busbar zoning constraint information.

[0030] Furthermore, in the busbar insulation section location information, according to the section identifier, phase identifier and adjacency relationship of each busbar insulation section, high-resistance isolation coupling branches are deployed at the corresponding detection positions. Each high-resistance isolation coupling branch includes a busbar-side coupling end, a withstand voltage coupling element, a current-limiting isolation element and a low-voltage-side signal end. The busbar-side coupling end is connected to the corresponding busbar insulation section, and the low-voltage-side signal end is led out to the low-voltage side of the switchgear. The withstand voltage coupling element and the current-limiting isolation element constitute a restricted coupling channel for low-energy perturbation signals, which is used to limit injected energy, reduce the influence of power frequency leakage and isolate the transmission of busbar-side potential to the low-voltage side.

[0031] Using a high-resistance isolation coupling branch connected to the target busbar insulation section as the signal injection terminal for the phase-to-ground detection path, and the switchgear grounding terminal as the detection reference terminal and return terminal, the busbar insulation sections traversed by the phase-to-ground detection path are determined according to the correlation between the busbar insulation sections from the high-resistance isolation coupling branch connection point to the switchgear grounding terminal. Two high-resistance isolation coupling branches connected to different phase busbar insulation sections are selected to form the signal injection terminal and response return terminal for the phase-to-phase detection path. The low-energy perturbation signal forms a transmission relationship through the phase-to-phase insulation medium between the two phase buses and is led out to the low-voltage side of the switchgear through the response return terminal. The busbar insulation sections traversed by the phase-to-phase detection path are determined according to the correlation between the busbar insulation sections from the connection points of the two high-resistance isolation coupling branches.

[0032] The corresponding section identifiers are written according to the access position of the high-resistance isolation coupling branch, the detection reference position, the response return position, and the order in which the busbar insulation section passes through each phase-to-ground detection path and phase-to-phase detection path. This forms the relationship between the path passing through the sections. The busbar insulation section, the high-resistance isolation coupling branch, the phase-to-ground detection path, the phase-to-phase detection path, and the relationship between the path passing through the sections are then registered to form the busbar zoning constraint information.

[0033] It should be noted that the high-resistance isolation coupling branch is obtained by setting up bus-side coupling terminals at the corresponding detection positions of each bus insulation section based on the bus insulation section positioning information, connecting the withstand voltage coupling element and the current limiting isolation element in series between the bus-side coupling terminal and the low-voltage side signal terminal, and then leading the low-voltage side signal terminal out to the low-voltage side of the switchgear.

[0034] S2: Based on the busbar partition constraint information, according to the phase-to-ground detection path and phase-to-phase detection path corresponding to the target busbar insulation section, the power frequency phase interval is selected, and power frequency phase window control is performed on the phase-to-ground detection path and phase-to-phase detection path to form a phase window routing instruction.

[0035] S2.1: For the relative-to-ground detection path in the busbar partition constraint information, the power frequency voltage of the corresponding phase is used as the phase reference. For the phase-to-phase detection path, the power frequency voltage between the corresponding phases is used as the phase reference. The current power frequency cycle is divided into continuous phase segments according to the power frequency reference relationship of each detection path to form path phase segmentation information.

[0036] Furthermore, in the busbar partition constraint information, the phase identifier of the relative detection path is matched with the power frequency voltage sampling record of the corresponding phase relative to the ground terminal, and the phase identifiers at both ends of the phase-to-phase detection path are matched with the power frequency voltage sampling record between the corresponding phases. In each power frequency voltage sampling record, the power frequency cycle boundary is defined by the zero-crossing time marker in the same direction. The time length between adjacent power frequency cycle boundaries is recorded as one power frequency cycle. The corresponding phase angle is calculated according to the time ratio of each sampling time marker relative to the start of the power frequency cycle. The interval between the phase angles corresponding to adjacent sampling time markers is defined as a continuous phase segment. The start and end time markers, start and end phase angles, associated detection paths, and power frequency reference relationships of the continuous phase segments are written into the path phase segmentation information.

[0037] S2.2: Based on the path phase segmentation information, the running response within the continuous phase segment is matched with the detection release benchmark of the corresponding detection path. Continuous phase segments that meet the detection release benchmark are merged into candidate power frequency phase intervals, and continuous phase segments that do not meet the detection release benchmark are excluded. The candidate power frequency phase intervals are then filtered by duration according to the transmission duration of the low-energy perturbation signal and the response acquisition duration to form power frequency phase intervals.

[0038] It should be noted that the test release criterion refers to the allowable range of operating response corresponding to the test path and power frequency phase position; the operating response refers to the state data used to characterize the current energized operating stability of the corresponding test path before the low-energy perturbation signal is sent, which is different from the response signal obtained after the low-energy perturbation signal is sent; the operating response is obtained by the low-voltage side sampling channel, switch cabinet status acquisition interface and bus operation monitoring interface, and includes at least electrical quantity stability records, switch status records, load status records and abnormal disturbance records.

[0039] Each acquisition record is appended with a sampling time stamp, and the paths are associated according to the relative detection path, the interphase detection path, and the relationship of the path segments corresponding to the sampling location. The acquisition records associated with the same detection path are arranged according to the sampling time stamp to obtain the running response of the corresponding detection path.

[0040] The normal operating status of the busbar refers to the operating status where the switchgear status acquisition interface associated with the corresponding detection path has not registered switch switching, protection actions and abnormal alarms, and the busbar operation monitoring interface has not registered abnormal disturbances. Furthermore, within a continuous power frequency cycle during which the corresponding detection path is in normal bus operation, the operating response arranged according to the sampling time scale and the corresponding phase position of the phase reference are recorded accordingly, and the allowable range of the operating response that remains consistent within a continuous power frequency cycle at the same phase position is written into the detection release basis. For each continuous phase segment in the path phase segmentation information, the running response between the start and end timestamps of the continuous phase segment is extracted. Then, the range of each segment is compared with the corresponding detection release benchmark according to the sampling timetamp order. Continuous phase segments whose running responses consistently fall within the detection release benchmark are written into the candidate power frequency phase interval, while continuous phase segments whose running responses exceed the detection release benchmark are removed from the candidate power frequency phase interval. Candidate power frequency phase intervals that are temporally connected are connected to form a continuous interval. The duration between the start and end timestamps of each continuous interval is calculated, and continuous intervals with a duration not less than the sum of the transmission duration of the low-energy perturbation signal and the response acquisition duration are retained to form the power frequency phase interval.

[0041] The transmission duration of the low-energy perturbation signal is determined by the number of encoding cycles required to complete one full encoding bit sequence transmission of the path encoding identifier, and is recorded in conjunction with the signal stabilization time after the encoded signal channel is connected to the path to be detected via the high-impedance isolation coupling branch; the response acquisition duration is determined by the sampling time required for the sampling channel to complete response signal sampling, sampling time stamp addition, and path marking within the same encoding cycle, and is recorded in conjunction with the time it takes for the response signal to fall back to the allowable range of the corresponding detection path's operating response; the transmission duration and response acquisition duration are jointly determined by the encoding cycle, the path encoding identifier length, the sampling frequency, and the channel calibration record of the high-impedance isolation coupling branch.

[0042] S2.3: Window-bind the power frequency phase interval with the corresponding detection path, and arrange the detection time slots of the relative ground detection path and the phase-to-phase detection path according to the time order of each power frequency phase interval. For detection paths with overlapping power frequency phase intervals, select one according to the detection priority of the bus insulation section associated with the path and arrange it. Exclude the unarranged detection paths from the current detection time slot arrangement to form path window arrangement information.

[0043] Furthermore, for each detection path, the start and end timestamps of the corresponding power frequency phase interval are registered in correspondence with the path number of the detection path; each power frequency phase interval is arranged from earliest to latest according to the start timestamp, and the start and end timestamps of the power frequency phase interval are written into the corresponding detection time slot in sequence; Before writing the current power frequency phase interval, the start and end timestamps of the current power frequency phase interval are compared with the start and end timestamps of the already written detection time slots. If the start timestamp of the current power frequency phase interval is earlier than the end timestamp of the already written detection time slot and the end timestamp is later than the start timestamp of the already written detection time slot, the corresponding detection path is considered as a detection path with overlapping power frequency phase intervals. For detection paths with overlapping power frequency phase intervals, they are sorted according to the detection priority of the bus insulation sections associated with each detection path. The detection paths with higher detection priority and their corresponding power frequency phase intervals are written into the current detection time slot, while the detection paths with lower detection priority and their corresponding power frequency phase intervals are not written into the current detection time slot. The detection paths, power frequency phase intervals, and detection time slots written into each detection time slot are registered in chronological order to form path window cataloging information.

[0044] S2.4: Based on the path window arrangement information, the detection path arranged by the detection time slot is determined as the path to be detected, and the path to be detected, the corresponding power frequency phase interval, the path code identifier and the detection time slot are associated and encapsulated to form a phase window routing instruction.

[0045] Furthermore, according to the time sequence of each detection time slot in the path window arrangement information, the detection paths written into each detection time slot are marked as paths to be detected; the path number of the path to be detected is used as the numerical encoding input, and the value and arrangement order of each encoding bit are determined according to the binary bits of the path number from the high bit to the low bit, and the value and arrangement order of each encoding bit are combined to form an encoding bit sequence combination, and the encoding bit sequence combination is marked as the path encoding identifier; for each path to be detected, the start and end timestamps of the corresponding power frequency phase interval, the path encoding identifier, and the detection time slot are written into the same routing record, and the routing records are arranged according to the time sequence of the detection time slots to form a phase window routing instruction.

[0046] S3: Based on the phase window routing command, the coded signal channel and sampling channel are connected on the low-voltage side. The low-energy perturbation signal with path coding is sent through the high-impedance isolation coupling branch, and time-stamp association and path marking are performed to form coded path response information.

[0047] S3.1: According to the phase window routing instruction, within the corresponding detection time slot, the path encoding identifier is loaded onto the low-energy perturbation signal, and the encoding signal channel and sampling channel corresponding to the path to be detected are connected on the low-voltage side. The encoding signal channel and sampling channel are connected to the path to be detected through the corresponding high-impedance isolation coupling branch.

[0048] Furthermore, the path to be detected corresponding to the current detection time slot is selected according to the time sequence of the detection time slot in the phase window routing instruction. The code bit sequence combination corresponding to the path code identifier of the path to be detected is written into the continuous coding position of the excitation voltage waveform. The carrier phase state in each continuous coding position is switched according to the code bit sequence combination to form a low-energy perturbation signal carrying the path code identifier. Using the start time of the current detection time slot as the connection point, the coded signal channel and the sampling channel are respectively connected to the low-voltage side of the high-impedance isolation coupling branch corresponding to the path to be detected, and the coded signal channel and the sampling channel are disconnected at the end time of the current detection time slot; the coded signal channel transmits a low-energy perturbation signal carrying the path coding identifier to the path to be detected through the high-impedance isolation coupling branch, and the response signal returned by the path to be detected through the high-impedance isolation coupling branch is introduced into the sampling channel.

[0049] It should be noted that the low-energy perturbation signal includes an excitation voltage waveform and a path coding identifier; the excitation voltage waveform adopts a sinusoidal carrier waveform, and the carrier phase state is switched according to the coding position combination of the path coding identifier within the continuous coding position to form a low-energy perturbation signal carrying the path coding identifier; the transmission frequency of the excitation voltage waveform avoids the main power frequency component and the main operating harmonic interference range in the corresponding detection path, and serves as the reference frequency for subsequent response segment synchronization, coding correlation calculation and apparent insulation admittance calculation; The encoding period of a continuous encoding position is jointly defined by the transmission duration of the low-energy perturbation signal, the response acquisition duration, and the duration of the power frequency phase interval within the current detection time slot; The amplitude of the excitation voltage waveform is determined according to the allowable injected energy of the high-impedance isolated coupling branch and the dynamic range of the sampling channel response.

[0050] S3.2: Within the power frequency phase interval corresponding to the path to be detected, a low-energy perturbation signal is sent to the path to be detected through the coded signal channel and the corresponding high-impedance isolation coupling branch, and the response signal of the path to be detected is collected through the sampling channel. The transmission time stamp of the low-energy perturbation signal and the sampling time stamp of the response signal are registered accordingly to form a path response record.

[0051] Furthermore, within the current detection time slot, the encoding signal channel is activated according to the starting time marker of the power frequency phase interval corresponding to the path to be detected. The low-energy perturbation signal carrying the path encoding identifier is sent to the path to be detected through the corresponding high-impedance isolation coupling branch according to the continuous encoding cycle. During the transmission of the low-energy perturbation signal, the control sampling channel continuously samples the response signal of the path to be detected through the corresponding high-impedance isolation coupling branch, and writes the sampling time marker of each response signal with the transmission time marker of the continuous encoding cycle, the path to be detected, and the path encoding identifier. When the end time marker of the power frequency phase interval is reached, the transmission of the low-energy perturbation signal and the sampling of the response signal are stopped, and the corresponding written content is arranged in the order of the sampling time marker to form a path response record.

[0052] S3.3: Based on the path encoding identifier, transmission time stamp and sampling time stamp, the path response record is time-stamped, and the time-stamped path response record is associated and marked to the path to be detected to form encoded path response information.

[0053] Furthermore, the transmission timestamps in the path response record are written into the transmission timestamp sequence according to the order of continuous coding periods, and the sampling timestamps are written into the sampling timestamp sequence according to the time sequence. For each sampling timestamp in the sampling timestamp sequence, the transmission timestamp corresponding to the continuous coding period in the transmission timestamp sequence is selected, and the transmission timestamp, the corresponding sampling timestamp, the path coding identifier, and the response signal are written into the same response association entry. The response association entries are collected according to the path to be detected, and the response association entries with the same path coding identifier under the same path to be detected are arranged according to the sampling timestamp order. The arranged response association entries are associated with the path to be detected to form the coded path response information.

[0054] S4: Perform encoding synchronization response separation on the encoded path response information to obtain the effective response components corresponding to the path to be detected, calculate the apparent insulation admittance of the path to be detected, and extract the path insulation feature information. At the same time, associate the path number to be detected with the path passing through the section relationship in the bus partition constraint information to form path admittance observation information.

[0055] S4.1: Based on the path encoding identifier, transmission time stamp, and sampling time stamp in the encoded path response information, the path response record is encoded and located, and the response segments corresponding to the low-energy perturbation signal are time-aligned according to the transmission time stamp and sampling time stamp to form an encoded synchronization response record.

[0056] Furthermore, based on the path coding identifier, path response records with the same path coding identifier are filtered in the coded path response information, and the corresponding transmission time stamp, sampling time stamp, and response signal are extracted from each path response record. Starting from each transmission time stamp, the time range of the response segment is divided according to the continuous coding period between adjacent transmission time stamps, and the response signals whose sampling time stamps fall into the corresponding time range are assigned to the corresponding response segments. The time difference between the sampling time stamp and the corresponding transmission time stamp in each response segment is calculated, and the obtained time difference is used as the time position of the response signal relative to the corresponding transmission time stamp. The response signals in each response segment are rearranged according to the time position to form a coded synchronization response record.

[0057] S4.2: Determine the corresponding encoding template based on the path encoding identifier, divide the encoded synchronization response record into multiple response segments according to the encoding period of the low-energy perturbation signal, perform time-domain alignment and encoding correlation calculation on each response segment and the encoding template to obtain the corresponding encoding correlation quantity, perform matching state identification on each response segment according to the encoding correlation quantity, retain the response segments whose encoding correlation quantity meets the matching condition, exclude the response segments that do not meet the matching condition, and perform co-coding accumulation on the retained response segments to obtain the effective response component corresponding to the path to be detected.

[0058] Furthermore, using the combination of coding bit order in the path coding identifier as an index, the arrangement order and value of each coding bit are expanded according to a continuous coding cycle to form a coding template corresponding to the low-energy perturbation signal; according to the time range between adjacent transmission time stamps in the coding synchronization response record, response signals that fall within the same time range and have the same path coding identifier are assigned to the same response segment according to the sampling time stamp. For each response segment, using the corresponding transmission time stamp as the starting point, the relative time position obtained by subtracting the transmission time stamp from the sampling time stamp of each response signal is compared item by item with the relative time position of each coding bit in the coding template. Response signals falling within the same coding bit time range are written into the corresponding coding bit position. The response value at each coding bit position is multiplied bit by bit with the coding bit value at the same coding bit position in the coding template and accumulated along the coding bit order to obtain the coding correlation quantity of each response segment. The coding correlation quantity is compared with the correlation quantity range in the matching conditions corresponding to the path coding identifier. Response segments falling within the correlation quantity range are retained, and response segments not falling within the correlation quantity range are excluded. Using the same coding bit position as the aggregation position, the response values ​​in the retained response segments are accumulated bit by bit and normalized according to the number of retained response segments to obtain the effective response components corresponding to the path to be detected.

[0059] It should be noted that within the power frequency phase interval corresponding to the path to be detected, low-energy perturbation signals carrying the same path coding identifier are continuously transmitted, and coding correlation calculations are performed on the response segments corresponding to each consecutive coding cycle to obtain a reference coding correlation quantity. At the same time, coding correlation calculations are performed on the coding template and the response segments without path coding identifiers to obtain a background coding correlation quantity. The sign direction of the reference coding correlation quantity and the maximum value of the absolute value of the background coding correlation quantity are written into the matching conditions corresponding to the path coding identifier. The correlation quantity range in the matching conditions corresponding to the path coding identifier can be written according to the upper and lower boundaries of the continuously stable distribution obtained by transmitting low-energy perturbation signals carrying the same path coding identifier within the corresponding power frequency phase interval under normal bus operation.

[0060] The effective response components include the response current waveform and the coded bit position.

[0061] S4.3: Calculate the apparent insulation admittance of the path to be detected based on the amplitude and phase relationships of the excitation voltage corresponding to the low-energy perturbation signal and the response current corresponding to the effective response component.

[0062] Furthermore, using the transmission time stamp of each consecutive coding cycle as a unified time starting point, the excitation voltage waveform in the low-energy perturbation signal and the response current waveform in the effective response component are arranged in correspondence according to the same time position. For each consecutive coding cycle, according to the transmission frequency of the low-energy perturbation signal, a first reference waveform and a second reference waveform with a phase difference of one-quarter cycle are generated within the consecutive coding cycle. The voltage value at each time position in the excitation voltage waveform is multiplied by the reference value of the first reference waveform and the second reference waveform at the same time position and accumulated to obtain two orthogonal components corresponding to the excitation voltage waveform. The response current waveform is multiplied and accumulated point by point in the same way to obtain two orthogonal components corresponding to the response current waveform. The excitation voltage amplitude, response current amplitude, excitation voltage phase angle, and response current phase angle are calculated using the two orthogonal components corresponding to the excitation voltage waveform and the response current waveform, respectively. The admittance values ​​of the response current amplitude and the excitation voltage amplitude are calculated, and the phase difference between the response current phase angle and the excitation voltage phase angle is calculated. The admittance value is used as the magnitude of the apparent insulation admittance, and the phase difference is used as the phase angle of the apparent insulation admittance to obtain the apparent insulation admittance of the path to be detected.

[0063] The formula for calculating the apparent insulation admittance of the path to be tested is: ; In the formula, This represents the apparent insulation admittance of the path to be tested; The magnitude of the apparent insulation admittance; This represents the square of the first orthogonal component corresponding to the response current waveform; It represents the square of the second orthogonal component corresponding to the response current waveform; This represents the square of the first orthogonal component corresponding to the excitation voltage waveform; This represents the square of the second orthogonal component corresponding to the excitation voltage waveform; The phase angle representing the apparent insulation admittance; This represents the arctangent operation in the four quadrants.

[0064] S4.4: According to the path number to be tested, associate the apparent insulation admittance with the corresponding test time marker, and arrange the apparent insulation admittance of the same path to be tested in sequence according to the test time marker within the continuous test time slot to form a path admittance observation sequence.

[0065] Furthermore, the apparent insulation admittance, corresponding test time stamp, test path number, and test time slot obtained from each test are written into the same admittance record; using the test path number as the aggregation identifier, admittance records with the same test path number are grouped into the same test path record group, and the admittance records in the same test path record group are arranged from earliest to latest according to the test time stamp; For adjacent admittance records after arrangement, the detection time slots corresponding to each admittance record are judged to be connected end to end according to the time sequence. Admittance records with consecutive detection time slots are grouped into the same consecutive detection time slot, and admittance records with discontinuous detection time slots are used as the starting admittance records of another consecutive detection time slot. Within each consecutive detection time slot, the apparent insulation admittances are connected in series from early to late according to the detection time marker, and the detection time marker and the path number to be detected are retained at the corresponding position of each apparent insulation admittance to form a path admittance observation sequence.

[0066] S4.5: Divide the path admittance observation sequence into continuous observation segments, perform differential calculation on adjacent apparent insulation admittances within each continuous observation segment, and perform interval merging and coding registration according to the continuous distribution of differential calculation values. Associate the coded registration content with the path number to be detected to form path insulation characteristic information.

[0067] Furthermore, in the path admittance observation sequence, the apparent insulation admittances are arranged from early to late according to the detection time scale. The apparent insulation admittances with continuous connection at the beginning and end of the detection time slots corresponding to adjacent admittance records are classified into the same continuous observation segment, and the apparent insulation admittances after the detection time slots are not continuously connected are taken as the starting record of another continuous observation segment. Within each continuous observation segment, the apparent insulation admittance corresponding to the previous detection time point is subtracted from the apparent insulation admittance corresponding to the current detection time point to obtain the differential calculation value of the corresponding adjacent detection time point interval. The differential calculation values ​​are arranged in the order of the detection time points. The change direction of adjacent differential calculation values ​​is continuously tracked along the detection time points. The admittance change interval is separated at the position where the change direction changes. The differential calculation values ​​with continuous change direction are connected in series to form the same admittance change interval. The interval position and change relationship of each admittance change interval in the continuous observation segment are written into the coded registration content, and the coded registration content is written in correspondence with the path number to be detected to form the path insulation feature information.

[0068] S4.6: Based on the path number to be tested, locate the corresponding path segment relationship in the busbar partition constraint information, and associate and encapsulate the path admittance observation sequence, path insulation feature information and path number to be tested according to the path segment relationship to form path admittance observation information.

[0069] Furthermore, the path number to be detected is compared item by item with the path numbers of each relative ground detection path and phase-to-phase detection path in the bus partition constraint information, and the path corresponding to the detection path with the same number is written into the path to be detected through the segment relationship. According to the order of the busbar insulation sections in the path segment relationship, the path admittance observation sequence and path insulation characteristic information are successively connected to the corresponding busbar insulation sections. Under the same path segment relationship, the path admittance observation sequence, path insulation characteristic information and the path number to be tested, which have been successively connected, are written into the same observation entry according to the order of the busbar insulation sections. The observation entries are then arranged according to the path number to be tested to form path admittance observation information.

[0070] S5: Based on the path admittance observation information, the apparent insulation admittance is jointly inverted to obtain the equivalent insulation admittance. The equivalent insulation admittance and path insulation characteristic information are classified according to the stable response range, insulation degradation characteristic information is identified, and the correlation output is performed to form the bus insulation detection status.

[0071] S5.1: Based on the path admittance observation information, the path admittance observation sequence corresponding to each path to be tested is collected into the bus insulation section it passes through, and the path association registration is performed on the paths to be tested that pass through the same bus insulation section to form the segment path observation relationship.

[0072] Furthermore, according to the relationship of the path passage sections in the path admittance observation information, the bus insulation sections in each path to be tested are matched one by one in the order of passage. The path admittance observation sequence of each path to be tested is written into the bus insulation sections that are passed through, and the path number to be tested and the order of passage of the bus insulation sections in the relationship of the path passage sections are written into the same record. For the same busbar insulation section, the test path numbers written into the busbar insulation section are arranged in numerical order, and the path admittance observation sequences corresponding to each test path number are arranged in the order of passage through the busbar insulation section. The test path numbers, path admittance observation sequences, and passage order arranged in the same busbar insulation section are written into the same section path record, and the section path records are arranged according to the section identifier of the busbar insulation section to form the section path observation relationship.

[0073] S5.2: The equivalent insulation admittance of each busbar insulation section is taken as the quantity to be inverted, and the apparent insulation admittance in the path admittance observation sequence is taken as the path observation value. According to the busbar insulation section through which each path to be detected passes, the path observation value and the corresponding quantity to be inverted are established to form the section path inversion relationship.

[0074] Furthermore, for each busbar insulation segment in the segment path observation relationship, the corresponding equivalent insulation admittance is listed as the quantity to be inverted, and the apparent insulation admittance at the same detection time scale in the path admittance observation sequence of each path to be tested is written into the corresponding path observation value; along each path to be tested, in the order of the busbar insulation segments traversed in the segment relationship, the path observation value of the path to be tested is written into each busbar insulation segment traversed, and the quantity to be inverted for the corresponding busbar insulation segment is associated at the same writing position; for each path to be tested that traverses the same busbar insulation segment, the path observation value, the corresponding quantity to be inverted, and the order of the busbar insulation segment traversed are written into the same segment path inversion record, and the segment path inversion records are arranged according to the path number to be tested to form the segment path inversion relationship.

[0075] S5.3: Calculate the inversion admittance corresponding to each path to be detected based on the inversion relationship of the segment path. Perform residual calculation on the inversion admittance and the apparent insulation admittance. Use the residual calculation value to iteratively correct the inversion quantities of the relevant bus insulation segments. The inversion quantities that meet the residual convergence requirements are determined as the equivalent insulation admittance of the corresponding bus insulation segments. The inversion quantities that do not meet the residual convergence requirements are taken as the correction quantities. Recalculate the corresponding inversion admittance and perform iterative correction until the residual convergence requirements are met to obtain the equivalent insulation admittance.

[0076] Furthermore, in the segment path inversion relationship, the segment path inversion record corresponding to the same path to be detected is used as the inversion entry. According to the order of the bus insulation segments in the path through the segment relationship, the inversion quantities of each bus insulation segment are added one by one to obtain the inversion admittance of the inversion entry. The inversion admittance is subtracted from the apparent insulation admittance in the inversion entry to obtain the residual calculation value. The residual calculation value, along with the corresponding path to be detected and the bus insulation sections traversed, is written into the section path inversion record. For inversion entries where the residual calculation value does not meet the residual convergence requirement, the bus insulation sections in the path traverse the order of the bus insulation sections. The current bus insulation section's inversion quantity is taken as the quantity to be corrected. The inversion quantities of the remaining bus insulation sections in the same path to be detected remain unchanged. The apparent insulation admittance is subtracted from the sum of the inversion quantities of the remaining bus insulation sections to obtain the replacement value of the quantity to be corrected. The replacement value is then used to overwrite the current quantity to be corrected. After completing the sequential correction of the bus insulation sections in each path to be tested, the inversion quantities are added together to obtain the inversion admittance and the residual calculation value is calculated. The inversion quantities that still do not meet the residual convergence requirements are replaced as correction quantities in the same way until the corresponding residual calculation value meets the residual convergence requirements. The inversion quantities of each bus insulation section at this time are written as the equivalent insulation admittance to obtain the equivalent insulation admittance.

[0077] It should be noted that the residual convergence requirement refers to the requirement that the calculated residual value between the inverted admittance and the apparent insulation admittance falls within the allowable range of residuals, and that the change in the calculated residual value after two adjacent iterations falls within the allowable range of residual changes.

[0078] S5.4: Arrange the equivalent insulation admittance and associated path insulation characteristic information of each bus insulation section according to the detection time scale, and match them with the stable response range of the bus insulation section. Mark the equivalent insulation admittance and path insulation characteristic information that fall within the stable response range as stable records, and mark the equivalent insulation admittance and path insulation characteristic information that deviate from the stable response range as deviation records.

[0079] Furthermore, according to the section identifier of the busbar insulation section, the equivalent insulation admittance, path insulation characteristic information and detection time scale are assigned to the corresponding section response record group, and arranged in order of earliest to latest detection time scale within each section response record group; within the continuous detection cycle corresponding to the normal operation state of the busbar, the numerical boundaries and characteristic boundaries corresponding to the continuously distributed and stable equivalent insulation admittance and path insulation characteristic information under the same busbar insulation section are written into the stable response range; For the equivalent insulation admittance and path insulation characteristic information corresponding to each detection time point, the corresponding stable response range is called according to the insulation section of the busbar to which it belongs. The equivalent insulation admittance is compared with the numerical boundary in the stable response range, and the consistency between the path insulation characteristic information and the characteristic boundary in the stable response range is confirmed. If the equivalent insulation admittance falls within the numerical boundary and the path insulation characteristic information is consistent with the characteristic boundary, it is written into the stability record. If the equivalent insulation admittance exceeds the numerical boundary or the path insulation characteristic information is inconsistent with the characteristic boundary, it is written into the deviation record.

[0080] Among them, the characteristic boundary in the stable response range is formed by the interval position boundary and change relationship boundary of the coded registration content in the path insulation characteristic information under normal bus operation. When confirming the consistency of the path insulation characteristic information, the coded registration content in the current path insulation characteristic information is compared with the characteristic boundary. If the start and end detection time markers of the admittance change interval fall within the interval position boundary, and the change direction, the number of consecutive segments, and the connection relationship of adjacent admittance change intervals are all consistent with the change relationship boundary, the path insulation characteristic information is confirmed to be consistent with the characteristic boundary. If any of the following situations occur, such as the start and end detection time markers of the admittance change interval exceeding the interval position boundary, inconsistent change direction, inconsistent number of consecutive segments, or inconsistent connection relationship of adjacent admittance change intervals, the path insulation characteristic information is confirmed to be inconsistent with the characteristic boundary.

[0081] S5.5: Along the detection time scale, the deviation records of the same busbar insulation section are spliced ​​into continuous segments, the change boundary corresponding to the continuous deviation records is extracted to form insulation degradation characteristic information, and the stable record and insulation degradation characteristic information are loaded into the detection record of the corresponding busbar insulation section to form the busbar insulation detection status.

[0082] Furthermore, the deviation records of the same busbar insulation section are arranged from earliest to latest according to the detection time scale. Deviation records that are adjacent without a stable record and whose corresponding detection time slots are connected continuously are grouped into the same continuous deviation segment. Within each continuous deviation segment, the corresponding contents of the first and last deviation records are written as the start boundary content and the end boundary content, respectively. The change relationship of continuous deviation relative to the stable response range within the continuous deviation segment is written into the same deterioration characteristic record according to the detection time scale order to form insulation deterioration characteristic information. Stability records and insulation degradation characteristic information under the same busbar insulation section are written into the same test record according to the test time scale, and the test records are associated with the section identifier of the busbar insulation section to form the busbar insulation test status.

[0083] It should be noted that insulation degradation characteristic information refers to the characterization information formed by the continuous deviation of the insulation section of the same busbar from the stable response range within a continuous detection time slot, which is used to reflect the changes in the insulation state of the busbar insulation section; including the content of the starting boundary, the content of the ending boundary, and the relationship between the changes in the continuous deviation from the stable response range.

[0084] Figure 2 The metal outer shell 1 serves as the supporting base of this device, used to fix and install the high-voltage A-phase current-limiting resistor 3, the high-voltage B-phase current-limiting resistor 4, and the high-voltage C-phase current-limiting resistor 5. It houses various high-voltage detection components and can withstand dust, water vapor, and external impacts on site, making it suitable for complex working conditions such as industrial mines and substations. At the same time, it also serves as electromagnetic shielding, avoiding distortion of detection data caused by strong electromagnetic interference on site. The three-phase symmetrical arrangement structure can eliminate measurement errors caused by layout deviations, and it is reliably connected to the grounding terminal 2, forming an equipotential safety protection cavity for the entire device. The grounding terminal 2 is located on the side of the metal casing 1. It can quickly conduct the fault current and residual charge of the equipment to the ground when the device insulation fails or the line leakage occurs, so as to prevent the casing from becoming live and causing electric shock accidents and ensure the safety of operation and maintenance. It can also build a stable zero potential measurement benchmark, suppress ground potential drift and noise interference, and ensure the accuracy of detection data such as insulation resistance and absorption ratio. At the same time, it can discharge the instantaneous large current of short circuit and protect the internal electrical components from being damaged by overvoltage. The high-voltage A-phase current-limiting resistor 3, high-voltage B-phase current-limiting resistor 4, and high-voltage C-phase current-limiting resistor 5 adopt an integrated solid-encapsulation structure with multi-layer umbrella skirts made of silicone rubber. The parameters and specifications of the three components are completely consistent, and each constitutes an independent high-voltage detection branch. When a DC test voltage is applied, the peak current of the circuit can be limited to prevent the internal high-voltage module and relay from being burned out instantly by a short circuit in the motor winding. Relying on the characteristics of silicone rubber in resisting pollution, moisture, and arc flashover, the electrical creepage distance is extended, effectively avoiding the problem of phase-to-phase and phase-to-ground leakage discharge. By switching the detection topology through three independent branches, three-phase-to-ground and phase-to-phase insulation detection can be completed. The resistance parameters remain stable under high and low temperature and humid conditions, ensuring the comparability of multiple test results. The copper connectors 6 mounted on the top of each current-limiting resistor have excellent conductivity, can be firmly locked to the high-voltage busbar terminal, have low contact resistance, and are not easily oxidized or loosened under long-term vibration of the equipment, ensuring reliable conduction of the high-voltage detection circuit and avoiding measurement data distortion caused by poor wiring contact. It can realize long-term grid connection of the device and the high-voltage busbar, eliminating the process of repeated disassembly and reassembly of traditional insulation testing, greatly improving the efficiency of operation and maintenance testing. At the same time, it is compatible with various specifications of wiring fasteners, making it more versatile for field installation. With the cooperation of all components, under the premise of high-voltage operation safety protection and environmental interference resistance, it can realize all-weather accurate online monitoring of the insulation status of the high-voltage busbar.

[0085] This embodiment also provides an online detection device for the insulation of high-voltage switchgear busbars, including: The metal casing serves as the supporting base for this device, and is used to fix and install the high-voltage A-phase current-limiting resistor, the high-voltage B-phase current-limiting resistor, and the high-voltage C-phase current-limiting resistor, forming an equipotential safety protection cavity for the entire machine. The grounding terminal is located on the side of the metal casing to protect the internal electrical components from damage caused by overvoltage. The high-voltage A-phase current-limiting resistor, high-voltage B-phase current-limiting resistor, and high-voltage C-phase current-limiting resistor adopt a silicone rubber multi-layer umbrella skirt integrated solid-sealing structure to maintain stable resistance parameters under high and low temperature and humid conditions, ensuring the comparability of multiple test results. Copper connectors have excellent conductivity and can be firmly locked to the high-voltage busbar terminals to prevent measurement data distortion caused by poor wiring contact.

[0086] In summary, this invention constructs segment path inversion relationships based on the relationships between the segments traversed by the path, and iteratively corrects the inversion quantities of each busbar insulation segment using apparent insulation admittance as the path observation value. This achieves the decoupling of the path response across multiple busbar insulation segments to the equivalent insulation admittance of the segments, thereby enabling accurate association of path insulation feature information with the corresponding segments. This is used to continuously identify deviations from the boundary and deterioration trends of local insulation states, improving the localization and stability of live-line detection.

[0087] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for online detection of busbar insulation in high-voltage switchgear, characterized in that, include: Collect bus topology status information of each phase bus in the high-voltage switchgear, divide it into multiple bus insulation sections, and configure high-resistance isolation coupling branches to form bus partition constraint information; Based on the busbar zoning constraint information, the power frequency phase interval is selected according to the relative-to-ground detection path and phase-to-phase detection path corresponding to the target busbar insulation section. Power frequency phase window control is then performed on the relative-to-ground detection path and phase-to-phase detection path to form a phase window routing instruction. Based on the phase window routing command, the coded signal channel and the sampling channel are connected on the low-voltage side. The low-energy perturbation signal with path coding is sent through the high-impedance isolation coupling branch, and time-stamp association and path marking are performed to form coded path response information. The coded path response information is separated into coded synchronous responses to obtain the effective response components corresponding to the path to be detected. The apparent insulation admittance of the path to be detected is calculated, and the path insulation feature information is extracted. At the same time, the path number to be detected is associated with the path passage section relationship in the bus zoning constraint information to form path admittance observation information. Based on the path admittance observation information, the apparent insulation admittance is jointly inverted to obtain the equivalent insulation admittance. The equivalent insulation admittance and path insulation characteristic information are classified according to the stable response range, insulation degradation characteristic information is identified, and the correlation output is performed to form the bus insulation detection status.

2. The online detection method for busbar insulation of high-voltage switchgear as described in claim 1, characterized in that, The specific steps for forming the busbar partition constraint information are as follows: Based on the bus topology status information, the continuous connection relationship and insulation boundary position of each phase bus are identified. Multiple bus insulation sections are divided along the continuous connection relationship of each phase bus, and the section identifier, phase identifier and adjacency relationship of each bus insulation section are registered to form bus insulation section positioning information. Based on the busbar insulation section location information, high-resistance isolation coupling branches are deployed at the detection locations corresponding to each busbar insulation section. A relative-to-ground detection path and a phase-to-phase detection path are constructed around each high-resistance isolation coupling branch. The busbar insulation sections traversed by each relative-to-ground detection path and phase-to-phase detection path are determined, forming the relationship between the path traversed sections. The busbar insulation sections, high-resistance isolation coupling branches, relative-to-ground detection paths, phase-to-phase detection paths, and the relationship between the path traversed sections are then registered accordingly to form busbar zoning constraint information.

3. The online detection method for busbar insulation of high-voltage switchgear as described in claim 1, characterized in that, The specific steps for selecting the power frequency phase interval are as follows: For the relative-to-ground detection path in the busbar partition constraint information, the power frequency voltage of the corresponding phase is used as the phase reference. For the phase-to-phase detection path, the power frequency voltage between the corresponding phases is used as the phase reference. The current power frequency cycle is divided into continuous phase segments according to the power frequency reference relationship of each detection path to form path phase segmentation information. Based on the path phase segmentation information, the running response within a continuous phase segment is matched with the detection release criteria of the corresponding detection path. Continuous phase segments that meet the detection release criteria are merged into candidate power frequency phase intervals, while continuous phase segments that do not meet the detection release criteria are excluded. The candidate power frequency phase intervals are then filtered by duration according to the transmission duration of the low-energy perturbation signal and the response acquisition duration to form power frequency phase intervals.

4. The online detection method for busbar insulation of high-voltage switchgear as described in claim 3, characterized in that, The specific steps for forming the phase window routing instruction are as follows: The power frequency phase interval is window-bound with the corresponding detection path, and the detection time slots of the relative ground detection path and the phase-to-phase detection path are arranged according to the time order of each power frequency phase interval. For detection paths with overlapping power frequency phase intervals, one is selected for arrangement according to the detection priority of the bus insulation section associated with the path. The detection paths that are not arranged are excluded from the current detection time slot arrangement to form path window arrangement information. Based on the path window arrangement information, the detection path arranged by the detection time slot is determined as the path to be detected, and the path to be detected, the corresponding power frequency phase interval, the path code identifier and the detection time slot are associated and encapsulated to form a phase window routing instruction.

5. The online detection method for busbar insulation of high-voltage switchgear as described in claim 1, characterized in that, The specific steps for forming the encoded path response information are as follows: According to the phase window routing instruction, within the corresponding detection time slot, the path coding identifier is loaded onto the low-energy perturbation signal, and the coding signal channel and sampling channel corresponding to the path to be detected are connected on the low-voltage side. The coding signal channel and sampling channel are connected to the path to be detected through the corresponding high-impedance isolation coupling branch. Within the power frequency phase interval corresponding to the path to be detected, a low-energy perturbation signal is sent to the path to be detected through the coded signal channel and the corresponding high-impedance isolation coupling branch, and the response signal of the path to be detected is collected through the sampling channel. The transmission time stamp of the low-energy perturbation signal and the sampling time stamp of the response signal are registered accordingly to form a path response record. Based on the path encoding identifier, transmission time stamp, and sampling time stamp, the path response records are time-stamped and then associated with the time-stamped path response records to the path to be detected, thus forming encoded path response information.

6. The online detection method for busbar insulation of high-voltage switchgear as described in claim 1 or 5, characterized in that, The specific steps for calculating the apparent insulation admittance of the path to be detected are as follows: Based on the path encoding identifier, transmission time stamp, and sampling time stamp in the encoded path response information, the path response record is encoded and located, and the response segments corresponding to the low-energy perturbation signal are time-aligned according to the transmission time stamp and sampling time stamp to form an encoded synchronous response record. The corresponding coding template is determined based on the path coding identifier. The coding synchronization response record is divided into multiple response segments according to the coding period of the low-energy perturbation signal. Temporal alignment and coding correlation calculation are performed on each response segment and the coding template to obtain the corresponding coding correlation quantity. Matching status identification is performed on each response segment according to the coding correlation quantity. Response segments whose coding correlation quantity meets the matching condition are retained, and response segments that do not meet the matching condition are excluded. The retained response segments are accumulated with the same coding to obtain the effective response component corresponding to the path to be detected. The apparent insulation admittance of the path to be detected is calculated based on the amplitude and phase relationships between the excitation voltage corresponding to the low-energy perturbation signal and the response current corresponding to the effective response component.

7. The online detection method for busbar insulation of high-voltage switchgear as described in claim 6, characterized in that, The specific steps for forming the path admittance observation information are as follows: According to the path number to be tested, the apparent insulation admittance is associated with the corresponding test time marker, and the apparent insulation admittance of the same path to be tested is sequentially arranged according to the test time marker within the continuous test time slot to form a path admittance observation sequence; The path admittance observation sequence is divided into continuous observation segments. Differential calculation is performed on adjacent apparent insulation admittances within each continuous observation segment. Interval merging and coding registration are performed according to the continuous distribution of differential calculation values. The coded registration content is associated with the path number to be detected to form path insulation feature information. Based on the path number to be tested, the corresponding path segment relationship is located in the busbar partition constraint information. The path admittance observation sequence, path insulation feature information and path number to be tested are associated and encapsulated according to the path segment relationship to form path admittance observation information.

8. The online detection method for busbar insulation of high-voltage switchgear as described in claim 1, characterized in that, The specific steps for obtaining the equivalent insulation admittance are as follows: The path admittance observation information is used to collect the path admittance observation sequence corresponding to each path to be tested into the bus insulation section it passes through, and the path association registration is performed on the paths to be tested that pass through the same bus insulation section to form the segment path observation relationship. The equivalent insulation admittance of each busbar insulation section is used as the quantity to be inverted, and the apparent insulation admittance in the path admittance observation sequence is used as the path observation value. According to the busbar insulation section through which each path to be detected passes, the path observation value and the corresponding quantity to be inverted are established to form the section path inversion relationship. The inversion admittance corresponding to each path to be detected is calculated based on the inversion relationship of the segment path. The inversion admittance and the apparent insulation admittance are calculated as residuals. The inversion quantities to be inverted in the relevant bus insulation sections are iteratively corrected using the residual calculation values. The inversion quantities that meet the residual convergence requirements are determined as the equivalent insulation admittance of the corresponding bus insulation section. The inversion quantities that do not meet the residual convergence requirements are taken as the correction quantities. The corresponding inversion admittance is recalculated and iteratively corrected until the residual convergence requirements are met, and the equivalent insulation admittance is obtained.

9. The online detection method for busbar insulation of high-voltage switchgear as described in claim 8, characterized in that, The specific steps for establishing the busbar insulation detection status are as follows: The equivalent insulation admittance and associated path insulation characteristic information of each bus insulation section are arranged according to the detection time scale and matched with the stable response range of the bus insulation section. The equivalent insulation admittance and path insulation characteristic information that fall within the stable response range are marked as stable records, and the equivalent insulation admittance and path insulation characteristic information that deviate from the stable response range are marked as deviation records. Along the detection timescale, the deviation records of the same busbar insulation section are spliced ​​into continuous segments. The change boundaries corresponding to the continuous deviation records are extracted to form insulation degradation characteristic information. The stable records and insulation degradation characteristic information are loaded into the detection records of the corresponding busbar insulation section to form the busbar insulation detection status.

10. An online detection device for busbar insulation of a high-voltage switchgear, based on the online detection method for busbar insulation of a high-voltage switchgear according to any one of claims 1 to 9, characterized in that, include: The metal casing serves as the supporting base for this device, and is used to fix and install the high-voltage A-phase current-limiting resistor, the high-voltage B-phase current-limiting resistor, and the high-voltage C-phase current-limiting resistor, forming an equipotential safety protection cavity for the entire machine. The grounding terminal is located on the side of the metal casing to protect the internal electrical components from damage caused by overvoltage. The high-voltage A-phase current-limiting resistor, high-voltage B-phase current-limiting resistor, and high-voltage C-phase current-limiting resistor adopt a silicone rubber multi-layer umbrella skirt integrated solid-sealing structure to maintain stable resistance parameters under high and low temperature and humid conditions, ensuring the comparability of multiple test results. Copper connectors have excellent conductivity and can be firmly locked to the high-voltage busbar terminals to prevent measurement data distortion caused by poor wiring contact.

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