High-low voltage switchgear control method and system

Abstract

The application discloses a high-low voltage switch device control method and system, and belongs to the technical field of high-low voltage switch device control. According to an operation instruction, a target high-voltage switch and a target low-voltage switch connected with a same transformer are determined. After the high-voltage switch auxiliary contact position is changed, a high-voltage charged display residual voltage sequence and a low-voltage control bus fluctuation sequence are collected, a residual voltage rebound window is generated, and a peak interval, a decay slope ratio and a polarity corresponding relationship are calculated in the window to form a homologous crosstalk fingerprint. When the homologous crosstalk fingerprint meets a preset crosstalk condition and a main loop current is lower than a no-load threshold value, it is determined that a lockout signal is a false lockout signal caused by reverse residual voltage, a low-voltage side is controlled to be connected with a discharge branch, and the high-voltage switch is prohibited from reclosing. After the residual voltage and the low-voltage fluctuation are rechecked and confirmed to be recovered, the prohibition is released, and the operation instruction is executed, so that the false lockout identification and the power supply recovery reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of high and low voltage switchgear control technology, and more specifically to high and low voltage switchgear control methods and systems. Background Technology

[0002] Existing high-voltage and low-voltage switchgear typically determine whether operation is permitted based on the high-voltage side energized indicator signal, the grounding switch position, and the low-voltage side control power supply voltage, respectively. In prefabricated substations used in scenarios such as hospital oxygen generator rooms or data center chiller pumps, after the high-voltage load switch is tripped, the large-capacity capacitor on the low-voltage side of the transformer still backflows to the primary side, creating a short-term residual voltage. Simultaneously, the low-voltage DC power supply module enters current-limiting oscillation, causing the high-voltage energized indicator and the low-voltage undervoltage relay to simultaneously exhibit abnormal switching within hundreds of milliseconds. This abnormality is neither a genuine energized mis-closing nor a low-voltage power failure, yet it causes the high-voltage switchgear to lock out and the low-voltage backup circuit to refuse operation, resulting in critical loads being unable to recover after a short-term mains power failure. Existing single-cabinet threshold judgments are insufficient to identify this transient coupling problem across voltage levels. Summary of the Invention

[0003] The purpose of this invention is to provide a control method and system for high and low voltage switchgear to address the shortcomings in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a high and low voltage switchgear control method, comprising: Obtain the operation instructions of the target switchgear, and determine the target high-voltage switch and the target low-voltage switch connected to the same transformer based on the operation instructions; After the auxiliary contact of the target high-voltage switch undergoes a displacement change, the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence are collected, and a residual voltage return window is generated based on the first reverse peak time of the two. Within the residual voltage bounce window, the peak interval, attenuation slope ratio, and polarity correspondence between the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence are calculated to generate a co-origin crosstalk fingerprint. When the same source crosstalk fingerprint meets the preset crosstalk condition and the target high voltage switch main circuit current is lower than the no-load threshold, it is determined that the current blocking signal is a false blocking signal caused by reverse residual voltage. According to the false blocking signal, the target low voltage switch is controlled to connect to the preset discharge branch, and the target high voltage switch is prohibited from closing again during the discharge period. When the re-acquired high-voltage live display residual voltage sequence exits the residual voltage jump-back window, and the low-voltage control bus fluctuation sequence is below the recovery threshold, the prohibition is lifted and the operation command is executed.

[0005] Preferably, determining the target high-voltage switch and the target low-voltage switch includes: Query the switchgear topology configuration table based on the target device number in the operation instruction to determine the voltage level and transformer number of the target device. When the target equipment is a high-voltage side equipment, the secondary low-voltage incoming switch is retrieved by the transformer number and used as the target low-voltage switch. When the target equipment is a low-voltage side device, the primary high-voltage load switch or high-voltage incoming switch is retrieved in reverse using the transformer number to which it belongs as the target high-voltage switch.

[0006] Preferably, generating the residual pressure bounce window includes: The change edge of the auxiliary contact of the target high-voltage switch is used as the synchronization zero point, and the high-voltage energized display residual voltage sequence and low-voltage control bus fluctuation sequence are latched from the cyclic buffer within the corresponding time period before and after the change edge. Offset elimination was performed based on the steady-state value before the displacement change, and the polarity of the low-voltage control bus fluctuation sequence after offset elimination was reversed. In the low-voltage control bus fluctuation sequence after polarity reversal mapping, the first reverse peak moment with the smallest distance from the first peak moment of the high-voltage live display residual voltage sequence is determined, and the residual voltage rebound window is generated by extending the time period from the synchronization zero point to the first reverse peak moment.

[0007] Preferably, the determination of the first peak time and the first reverse peak time includes: In the high-voltage live display residual voltage sequence after offset elimination, the local peak point that appears earliest after the synchronization zero point and whose amplitude is greater than the preset effective residual voltage amplitude is determined as the first peak point of high voltage. In the low-voltage control bus fluctuation sequence after polarity reversal mapping, local peaks with amplitudes greater than the preset effective amplitude of low-voltage fluctuations are taken as candidate points for reverse peaks. Calculate the time distance between each candidate reverse peak point and the first peak point of the high voltage, and determine the candidate reverse peak point with the smallest time distance as the first reverse peak point.

[0008] Preferably, the generation of homologous crosstalk fingerprints includes: Within the residual pressure rebound window, the high-pressure peak point and the low-pressure reverse peak point are determined respectively, and the peak interval is calculated based on the peak times of the two. Starting from the high-pressure peak point and the low-pressure reverse peak point respectively, find the sampling points that attenuate to the corresponding peak value by a preset ratio, and calculate the attenuation slope ratio between the high-pressure residual voltage attenuation slope and the low-pressure fluctuation attenuation slope. Based on the amplitude of the high-voltage peak point, the reverse mapping amplitude of the low-voltage reverse peak point, and the amplitude of the low-voltage reverse peak point in the original low-voltage control bus fluctuation sequence, the polarity correspondence is determined, and the same-source crosstalk fingerprint is formed by the peak interval, attenuation slope ratio, and polarity correspondence.

[0009] Preferably, determining that the current blocking signal is a false blocking signal includes: When the peak interval in the same-origin crosstalk fingerprint is less than or equal to the peak interval threshold, the attenuation slope ratio is within the preset slope ratio range, and the polarity correspondence is reverse same-origin, the same-origin crosstalk fingerprint is determined to meet the preset crosstalk condition. Within the preset current confirmation interval after the residual pressure return window ends, calculate the effective value of the three-phase main circuit current of the target high-voltage switch, and take the maximum value among the three-phase current effective values ​​as the main circuit confirmation current. When the main circuit confirms that the current is lower than the no-load threshold, and the current blocking signal comes from the live display blocking circuit or the closing permission blocking circuit, the current blocking signal is determined to be a false blocking signal caused by the reverse residual voltage.

[0010] Preferably, controlling the target low-voltage switch to connect to the preset discharge branch based on the pseudo-blocking signal includes: Based on the target low-voltage switch number and the corresponding transformer number associated with the false blocking signal, it is confirmed that the target low-voltage switch and the target high-voltage switch are connected to the same transformer. When the target low-voltage switch is in the open position and the low-voltage bus voltage is lower than the preset safe access voltage, the control bleed control switch is closed, so that the preset bleed branch including the bleed resistor is connected to the low-voltage bus corresponding to the target low-voltage switch. The discharge start time is recorded based on the closing feedback of the discharge control switch. If no closing feedback is received within the preset feedback time, the target high-voltage switch remains in the prohibited closing state.

[0011] Preferably, determining whether to exit the residual voltage jump-back window in a high-voltage live display residual voltage sequence includes: The zero point of the retest is taken as the disconnection feedback moment of the discharge control switch, and the start and end times of the original residual voltage jump window relative to the position change edge of the auxiliary contact are mapped to the retest time axis to obtain the retest observation window. The high-voltage live display signal in the observation window of the retest was reacquired and offset was eliminated based on the stable interval before the retest zero point to obtain the retest high-voltage offset sequence. When there is no effective local peak value with an absolute amplitude greater than the high voltage recovery threshold within the retest observation window, it is determined that the high voltage live display residual voltage sequence exits the residual voltage jump window.

[0012] Preferably, lifting the restriction and executing the operation instruction includes: The low-voltage recovery threshold is adaptively determined based on the rated voltage of the low-voltage control bus, the standard deviation of the low-voltage noise before the displacement change, and the amplitude of the previous low-voltage reverse peak value. The maximum absolute value of the retested low-voltage fluctuation is judged within the retest observation window and its subsequent delay interval to see if it is lower than the low-voltage recovery threshold. When the high-voltage live display residual voltage sequence exits the residual voltage return window, the low-voltage control bus fluctuation sequence is lower than the low-voltage recovery threshold, the discharge control switch is in the disconnected feedback state and there are no other blocking abnormalities, clear the high-voltage reclosing prohibition sign and the false blocking sign. If the original operation command has not been revoked and the preset effective time has not been exceeded, restore the closing permission signal of the target high-voltage switch and execute the operation command.

[0013] The present invention also provides a high and low voltage switchgear control system, including: an instruction parsing and topology association module, a residual voltage bounce window generation module, a crosstalk fingerprint generation module, a discharge interlocking control module, and a recovery and retesting module.

[0014] The technical effects and advantages provided by the present invention in the above technical solution are as follows: This invention differs from existing technologies that rely solely on high-voltage switchgear energization signals, grounding switch positions, or single-point threshold values ​​of low-voltage bus voltage for blocking judgment. This invention uses the change edge of the auxiliary contact of the target high-voltage switch as a unified triggering reference, simultaneously acquiring the high-voltage energization residual voltage sequence and the low-voltage side control bus fluctuation sequence of the same transformer. It determines the moment of the first reverse peak by mapping the polarity of the low-voltage fluctuations, thereby generating a residual voltage rebound window. This core technology does not simply determine whether a signal exceeds a limit, but rather correlates and identifies the high-voltage side residual voltage rebound and the low-voltage side bus reverse disturbance within a short physical process after the same switch action. This accurately captures cross-voltage level coupling anomalies caused by low-voltage side capacitor backflow and low-voltage control power supply oscillations. This solves the problem of existing equipment mistaking backflow residual voltage for actual energization blocking, leading to high-voltage switch refusal to close and low-voltage power supply recovery failure, thus improving the targeting and reliability of anomaly identification.

[0015] Furthermore, this invention extracts the peak interval, attenuation slope ratio, and polarity correspondence within the residual voltage jump-back window to form a common-source crosstalk fingerprint. Combined with the physical verification condition that the target high-voltage switch main circuit current is below the no-load threshold, it determines whether the blocking signal is a false blocking signal caused by backflow residual voltage. After determination, instead of directly allowing closing, it controls the low-voltage side of the same transformer to connect to a preset discharge branch, and prohibits the target high-voltage switch from closing again during the discharge period. Operation is resumed only after retesting confirms that the high-voltage residual voltage has exited the original residual voltage jump-back window and that the low-voltage bus fluctuation is below the adaptive recovery threshold. This technical approach forms a continuous closed loop of identification-discharge-prohibition of re-closing-retest recovery, avoiding both the safety risk of accidental closing with residual voltage and the inability to restore power to critical loads due to prolonged false blocking. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is the overall flowchart of the control method for high and low voltage switchgear.

[0018] Figure 2 A flowchart illustrating the topology association between high and low voltage switches.

[0019] Figure 3 Flowchart for generating a residual pressure bounce window.

[0020] Figure 4 This is a flowchart for crosstalk determination.

[0021] Figure 5 This is a flowchart for the release and recovery process. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1, please refer to Figure 1 As shown, the high and low voltage switchgear control method described in this embodiment includes: Obtain the operation instructions of the target switchgear, and determine the target high-voltage switch and the target low-voltage switch connected to the same transformer based on the operation instructions.

[0024] In one possible implementation, the present invention pre-stores a switchgear topology configuration table, which includes at least the equipment number, cabinet number, switch number, voltage level, transformer number, primary or secondary side identifier, communication address, and switch purpose identifier; wherein, the switch purpose identifier includes high-voltage incoming switch, high-voltage load switch, low-voltage incoming switch, low-voltage bus tie switch, or low-voltage feeder switch.

[0025] When operators issue operation commands through the background monitoring system, local human-machine interface, or remote dispatch interface, the system receives the operation commands and parses them to obtain the target device number, operation type, and command source. The operation type includes closing, opening, trial closing, or restoring power supply. Based on the target device number, the system queries the corresponding record in the switchgear topology configuration table to determine the transformer number and voltage level to which the target device belongs.

[0026] Please see Figure 2 As shown, when the voltage level of the target equipment is high-voltage, the switch corresponding to the target equipment is identified as the target high-voltage switch. Using the transformer number to which the target high-voltage switch belongs as the search condition, the switch with the secondary side identified as low-voltage and the switch purpose identified as a low-voltage incoming switch is searched in the switch equipment topology configuration table. The found switch is identified as the target low-voltage switch connected to the same transformer as the target high-voltage switch. If multiple low-voltage incoming switches exist under the same transformer number, the low-voltage incoming switch in the same operating segment as the target high-voltage switch is selected first. If multiple switches still exist, the low-voltage incoming switch whose current auxiliary contact status is closed or in standby mode is selected.

[0027] When the voltage level of the target device is low voltage, the switch corresponding to the target device is identified as the target low voltage switch, and the primary side is identified as high voltage and the switch purpose is identified as high voltage load switch or high voltage incoming line switch according to the transformer number to which it belongs. The found switch is identified as the target high voltage switch.

[0028] After identifying the target high-voltage switch and the target low-voltage switch, their communication addresses and auxiliary contact status are read, and an associated operation record containing the target high-voltage switch number, the target low-voltage switch number, the corresponding transformer number, and the operation type is generated. This record is used for subsequent acquisition of high-voltage live display residual voltage sequence and low-voltage control bus fluctuation sequence. If no corresponding low-voltage switch or high-voltage switch under the same transformer number is found, the operation command is not executed, and a topology association missing alarm is output.

[0029] Please see Figure 3 As shown, after the auxiliary contact of the target high-voltage switch undergoes a displacement change, the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence are collected, and a residual voltage return window is generated based on the first reverse peak time of the two.

[0030] In one possible implementation, the system includes an input acquisition terminal and an analog acquisition terminal. The input acquisition terminal is used to receive auxiliary contact signals from the target high-voltage switch, and the analog acquisition terminal is used to acquire high-voltage live display signals and low-voltage control bus signals, respectively. The high-voltage live display signal is the voltage or equivalent voltage signal output from the live display device of the high-voltage switchgear where the target high-voltage switch is located, and the low-voltage control bus signal is the voltage signal of the control bus of the low-voltage switchgear where the target low-voltage switch is located, which is connected to the same transformer as the target high-voltage switch.

[0031] Upon receiving an operation command, the status of the auxiliary contacts of the target high-voltage switch is continuously monitored. When the auxiliary contact changes from closed to open, or from open to closed, and this state change continues for a preset confirmation time, the level transition edge corresponding to the state change is determined as a position change edge, and the time corresponding to the position change edge is set as the synchronization zero point t0. The preset confirmation time can be from 5ms to 20ms to avoid false triggering caused by auxiliary contact jitter.

[0032] To avoid data loss due to restarting sampling after a potential change edge, a cyclic buffer method is used to continuously sample the high-voltage energized display signal and the low-voltage control bus signal. The sampling frequency can be set from 1kHz to 5kHz. After detecting the potential change edge, data within a first preset duration before t0 to a second preset duration after t0 is extracted from the cyclic buffer, for example, data from 100ms before t0 to 800ms after t0, forming the high-voltage energized display residual voltage sequence UH(ti) and the low-voltage control bus fluctuation sequence UL(ti), respectively, where ti is the sampling time relative to the synchronization zero point t0.

[0033] Subsequently, the steady-state interval before the displacement change is selected as the reference interval. This steady-state interval can be from 80 ms before t0 to 20 ms before t0. The average value UH0 of the high-voltage live display signal and the average value UL0 of the low-voltage control bus signal within this steady-state interval are calculated, and UH0 and UL0 are used as the steady-state values ​​before the displacement change. To improve anti-interference capability, the maximum and minimum values ​​within the steady-state interval can be removed before calculating the average value. Offset elimination is performed based on the steady-state values ​​before the displacement change, resulting in the high-voltage offset sequence ΔUH(ti) = UH(ti) - UH0 and the low-voltage offset sequence ΔUL(ti) = UL(ti) - UL0.

[0034] Furthermore, the low-voltage offset sequence is reversed in polarity to obtain the reverse low-voltage fluctuation sequence ΔULR(ti) = -ΔUL(ti). Through this processing, the decreasing disturbance caused by the reverse residual voltage or the current-limiting oscillation of the charging module on the low-voltage control bus is converted into a peak characteristic in the same direction as the high-voltage live display residual voltage rebound, thus facilitating the comparison of the peak correspondence between the two under the same time reference.

[0035] Starting from the synchronization zero point t0, the first peak point is searched in the high-voltage offset sequence ΔUH(ti). Specifically, when the amplitude of a certain sampling point is greater than the amplitudes of its preceding and following sampling points, and the amplitude of this sampling point is greater than the preset effective residual voltage amplitude, this sampling point is regarded as a candidate high-voltage peak point; according to the chronological order, the earliest appearing candidate high-voltage peak point is determined as the first peak point of the high-voltage live display residual voltage sequence, and its corresponding time is recorded as tH1. The preset effective residual voltage amplitude can be set according to the rated output range of the live display device, for example, set to 5% to 15% of the steady-state value UH0 before the potential change.

[0036] After obtaining the initial high-voltage peak time tH1, candidate points for the reverse peak are searched in the reverse low-voltage fluctuation sequence ΔULR(ti). The candidate point for the reverse peak is a sampling point whose amplitude is greater than the amplitudes of its preceding and following sampling points, and whose amplitude is greater than the preset effective amplitude of the low-voltage fluctuation. The preset effective amplitude of the low-voltage fluctuation can be set to 1% to 5% of the rated voltage of the low-voltage control bus. The time distance |tLj-tH1| between the corresponding time tLj of each candidate point for the reverse peak and the initial high-voltage peak time tH1 is calculated, and the candidate point for the reverse peak with the smallest time distance is determined as the initial reverse peak point, and its corresponding time is denoted as tR.

[0037] When no high-voltage peak candidate point or no reverse peak candidate point is found, no residual pressure back-jump window is generated, and the current anomaly is handled by the normal interlocking judgment process. When the first reverse peak time tR is successfully obtained, the time period between the synchronization zero point t0 and the first reverse peak time tR is used as the base window. Specifically, the base window is [t0, tR]. When the interval between tR and t0 is less than the preset minimum window width, the window end point is padded to the time corresponding to the preset minimum window width, starting from t0.

[0038] A residual voltage bounce window is generated by extending the basic window forward by a first preset margin and extending it backward by a second preset margin at the end of the basic window. The first and second preset margins can be set to 10ms to 30ms, respectively. To avoid the window exceeding the range of the acquired sequence, the starting point of the extended window must not be earlier than the starting sampling time of the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence, and the ending point of the extended window must not be later than the ending sampling time of both. The residual voltage bounce window obtained in this way is used to limit the calculation range of subsequent homogeneous crosstalk fingerprints, so that subsequent judgments focus on the short-term abnormal process formed by the high-voltage residual voltage bounce and the low-voltage bus reverse fluctuation after the auxiliary contact displacement.

[0039] Please see Figure 4As shown, within the residual voltage bounce window, the peak interval, attenuation slope ratio, and polarity correspondence between the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence are calculated to generate a co-origin crosstalk fingerprint.

[0040] In one possible implementation, after generating the residual pressure rebound window, the start time ta and end time tb of the residual pressure rebound window are read, and sampling points located between ta and tb are extracted from the high-pressure offset sequence ΔUH(ti) and the low-pressure offset sequence ΔUL(ti) that have completed offset elimination, respectively forming the high-pressure residual pressure subsequence ΔUHw(ti) and the low-pressure fluctuation subsequence ΔULw(ti) within the window. Simultaneously, the low-pressure fluctuation subsequence within the window is subjected to polarity reversal mapping to obtain the reverse low-pressure subsequence ΔULRw(ti) = -ΔULw(ti), which is used for comparison with the high-pressure residual pressure subsequence in the same direction of peak value.

[0041] The high-voltage peak point is determined from the high-voltage residual voltage subsequence ΔUHw(ti) within the window. Specifically, the sampling point with the largest absolute amplitude within the window is selected as a candidate high-voltage peak point. When the absolute amplitude of this sampling point is greater than the preset effective amplitude of the high-voltage peak, and its amplitude is greater than the amplitudes of the adjacent sampling points, the sampling point is determined as the high-voltage peak point, and its corresponding time is denoted as tHP, and its amplitude is denoted as AHP. If the sampling point with the largest absolute amplitude is located at the boundary of the residual voltage rebound window, at least two sampling points adjacent to this sampling point are selected for comparison. When a local peak cannot be determined, the high-voltage peak is deemed invalid.

[0042] Specifically, based on the high-pressure peak point, a low-pressure reverse peak point is determined in the reverse low-pressure subsequence ΔULRw(ti). Specifically, a sampling point with the same polarity as the high-pressure peak point and the largest absolute amplitude is found. When the absolute amplitude of this sampling point is greater than the preset effective amplitude of the low-pressure peak, this sampling point is determined as the low-pressure reverse peak point, its corresponding time is denoted as tLP, and the amplitude after reverse mapping is denoted as ALR. The amplitude of the low-pressure reverse peak point in the original low-pressure fluctuation subsequence ΔULw(ti) is denoted as ALP, and ALP = -ALR. Thus, the reverse low-pressure peak point used for same-direction comparison and the original low-pressure peak point used for polarity determination can be clearly distinguished.

[0043] After determining the high-voltage peak point and the low-voltage reverse peak point, the peak interval ΔT is calculated using the formula: ΔT = |tHP - tLP|. This peak interval characterizes the temporal proximity of the high-voltage live-line indicator residual voltage rebound and the low-voltage control bus reverse fluctuation.

[0044] Subsequently, the attenuation slope ratio is calculated. Specifically, starting from the high-voltage peak point tHP, the sampling point that first satisfies |ΔUHw(ti)|≤k·|AHP| in ΔUHw(ti) is searched along the time-increasing direction, and its time is recorded as tHD, where k is a preset attenuation ratio, which can be 0.3 to 0.5; if the sampling point is not found, tb is used as tHD. The high-voltage residual voltage attenuation slope is calculated according to SH=(|AHP|-|ΔUHw(tHD)|) / (tHD-tHP). If tHD=tHP, then one sampling period is used as the denominator for calculation.

[0045] Starting from the low-voltage reverse peak point tLP, search for the first sampling point in ΔULRw(ti) that satisfies |ΔULRw(ti)|≤k·|ALR| along the time-increasing direction, and record its time as tLD; if no sampling point is found, then tb is used as tLD. Calculate the low-voltage fluctuation attenuation slope according to SL=(|ALR|-|ΔULRw(tLD)|) / (tLD-tLP). If SL is less than the preset minimum slope value, the current window is marked as having an invalid slope and will not participate in the generation of the same-source crosstalk fingerprint; if SL is valid, calculate the attenuation slope ratio R=SH / SL.

[0046] Further calculate the polarity correspondence P. Specifically, when the product of AHP and the original low-pressure peak ALP is less than zero, and the product of AHP and the reverse-mapped low-pressure peak ALR is greater than zero, P is recorded as reverse homogeneous; when the product of AHP and ALP is greater than zero, or the product of AHP and ALR is less than zero, P is recorded as non-reverse homogeneous. If more than a preset number of sign alternations occur within a preset number of sampling points before or after the high-pressure peak point or low-pressure peak point, for example, more than 3 sign alternations occur within 5 sampling points before and after, then P is recorded as polarity unstable.

[0047] Finally, the peak interval ΔT, attenuation slope ratio R, and polarity correspondence P are used to generate a common-source crosstalk fingerprint F, which can be represented as F={ΔT, R, P}. The generated common-source crosstalk fingerprint is associated with the current operation command, the target high-voltage switch number, the target low-voltage switch number, and the start and end times of the residual voltage jump-back window, and stored for subsequent determination of whether the current blocking signal is a false blocking signal caused by reverse residual voltage.

[0048] It should be noted that if the effective high voltage peak point or the effective low voltage reverse peak point is not determined within the residual pressure rebound window, or if the attenuation slope ratio cannot be effectively calculated, then no co-current crosstalk fingerprint will be generated, and the current blocking signal will be handed over to the conventional blocking logic for processing.

[0049] Please see Figure 5As shown, when the same-source crosstalk fingerprint meets the preset crosstalk condition and the target high-voltage switch main circuit current is lower than the no-load threshold, the current blocking signal is determined to be a false blocking signal caused by reverse residual voltage. Based on the false blocking signal, the target low-voltage switch is controlled to connect to the preset discharge branch, and the target high-voltage switch is prohibited from closing again during the discharge period.

[0050] In one possible implementation, firstly, preset crosstalk conditions are pre-stored. These preset crosstalk conditions include a peak interval threshold Tmax, a lower limit of the attenuation slope ratio Rmin, an upper limit of the attenuation slope ratio Rmax, and a polarity correspondence requirement. Specifically, Tmax can be set to 20ms to 80ms, Rmin to 0.4 to 0.8, Rmax to 1.8 to 2.5, and the polarity correspondence requirement is that the polarity correspondence P is reversed and of the same origin. These parameters can be adjusted based on the target transformer capacity, the response time of the energized display device, and the rated voltage of the low-voltage control bus, and are stored in a parameter area.

[0051] First, it is determined whether the co-source crosstalk fingerprint F is valid. Specifically, when the peak interval ΔT is a valid value, the attenuation slope ratio R is a finite value greater than zero, the polarity correspondence P has been determined, and there are no invalid peak, invalid slope, or unstable polarity flags, the co-source crosstalk fingerprint F is determined to be valid; otherwise, no false locking determination is performed, and the current locking signal is handed over to the conventional locking logic for processing.

[0052] If the co-source crosstalk fingerprint F is valid, it is determined whether it meets the preset crosstalk conditions. Specifically, when ΔT≤Tmax, Rmin≤R≤Rmax, and P is a reverse co-source, the co-source crosstalk fingerprint F is determined to meet the preset crosstalk conditions. If any of the above conditions are not met, it is considered that the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence do not have the reverse residual voltage co-source characteristics, and the current blocking signal is not determined to be a false blocking signal.

[0053] Furthermore, confirm the source and occurrence time of the current blocking signal. The current blocking signal is a blocking signal output by the energized display blocking circuit or closing permission blocking circuit of the target high-voltage switch within a preset confirmation period after the auxiliary contact position change edge of the target high-voltage switch and after the end of the residual voltage return window. The preset confirmation period can be 50ms to 300ms. If the blocking signal originates from grounding switch blocking, cabinet door blocking, mechanical interlocking, or protection trip blocking, it will not be treated as a false blocking signal caused by reverse residual voltage.

[0054] After confirming the source of the blocking signal, the main circuit current of the target high-voltage switch is collected. The main circuit current can be provided by the current transformer or the electronic current sensor of the high-voltage cabinet where the target high-voltage switch is located. After the end time tb of the residual voltage rebound window, a preset current confirmation interval is entered, and the preset current confirmation interval can be 40ms to 200ms. Within this interval, the instantaneous current values of phase A, phase B and phase C are collected respectively, and the effective values Ia, Ib and Ic of each phase current are calculated according to one power frequency cycle or half a power frequency cycle, and the maximum value among the three is taken as the main circuit confirmation current Imax.

[0055] Wherein, the no-load threshold I0 can be set according to 0.5% to 3% of the rated current of the target high-voltage switch; it can also be set according to the upper limit of the no-load current of the transformer connected to the target high-voltage switch plus a preset margin. The main circuit confirmation current Imax is compared with the no-load threshold I0. When Imax<I0 and the comparison result holds for at least two consecutive current calculation cycles, it is determined that the main circuit current of the target high-voltage switch is lower than the no-load threshold. If any phase current reaches or exceeds the no-load threshold, or there are faults such as wire breakage, over-limit, communication interruption, and transformer saturation flag in the current sampling channel, the false blocking determination will not be performed, and the original blocking state will be maintained.

[0056] When it is simultaneously confirmed that the same-source crosstalk fingerprint F meets the preset crosstalk condition, the current blocking signal comes from the live display blocking loop or the closing permission blocking loop, and the main circuit confirmation current Imax of the target high-voltage switch is lower than the no-load threshold I0, it is determined that the current blocking signal is a false blocking signal caused by back-injected residual voltage.

[0057] In this embodiment, after the false blocking signal is generated, the number of the target low-voltage switch, the number of the target high-voltage switch and the number of the affiliated transformer stored in association with the false blocking signal are read, and it is confirmed that the target low-voltage switch and the target high-voltage switch are connected to the same transformer. If the topological association relationship is inconsistent, the discharging operation is not performed, and the blocking state of the target high-voltage switch is maintained.

[0058] Wherein, the preset discharge branch is arranged in the low-voltage cabinet where the target low-voltage switch is located, and can be connected in parallel between the low-voltage bus side of the target low-voltage switch and the neutral line, or connected in parallel between the low-voltage bus side of the target low-voltage switch and the protective grounding terminal. The preset discharge branch includes a discharge control switch and a discharge resistor, and the discharge control switch can be a contactor, a solid-state switch or a controllable switch with an auxiliary contact. The resistance value of the discharge resistor is pre-set according to the rated voltage of the low-voltage control bus and the allowable discharge current, so that the residual charge on the low-voltage side can be released after connection, and the short-time current allowed by the low-voltage cabinet will not be exceeded at the same time.

[0059] Before performing the discharge, the auxiliary contact status of the target low-voltage switch and the low-voltage bus voltage are read. When the target low-voltage switch is in the open position and the low-voltage bus voltage is lower than the preset safe access voltage, a closing command is output to the discharge control switch, causing the preset discharge branch to connect to the low-voltage bus corresponding to the target low-voltage switch. If the target low-voltage switch is in the closed position, the discharge branch connection is first prohibited, and a low-voltage switch not in the open position prompt is output; if the low-voltage bus voltage is higher than the preset safe access voltage, the discharge branch is kept open to prevent the discharge branch from being accidentally connected under normal energized conditions.

[0060] After the discharge control switch is closed, the auxiliary contact of the discharge control switch is used to confirm that the discharge branch has been connected, and the discharge start time td is recorded. If no closing feedback is received from the discharge control switch within the preset feedback time, the discharge branch connection is determined to have failed, the discharge command is stopped, and the target high-voltage switch remains in the prohibited closing state.

[0061] During the discharge process, a closing prohibition signal is output to the closing permission circuit of the target high-voltage switch, and a high-voltage re-closing prohibition flag is set in the control logic. This high-voltage re-closing prohibition flag is associated with a false interlocking flag, the target high-voltage switch number, and the discharge start time, thus intercepting closing commands issued by the background monitoring system, local HMI, or remote dispatch interface. For the local closing circuit of the target high-voltage switch, its closing permission contact can also be disconnected via a closing interlocking relay, preventing re-closing during the discharge period.

[0062] During the discharge process, the low-voltage bus voltage and the status of the discharge branch are continuously collected. When the preset minimum discharge time is reached and the low-voltage bus voltage drops below the preset discharge completion voltage, a disconnect command is output to the discharge control switch, causing the preset discharge branch to exit. If the low-voltage bus voltage still does not drop below the preset discharge completion voltage after the preset maximum discharge time is reached, the discharge branch is disconnected and a discharge timeout alarm is generated. At the same time, the target high-voltage switch remains in the prohibited closing state, awaiting subsequent review and processing.

[0063] When the re-acquired high-voltage live display residual voltage sequence exits the residual voltage jump-back window, and the low-voltage control bus fluctuation sequence is below the recovery threshold, the prohibition is lifted and the operation command is executed.

[0064] In one possible implementation, after the preset discharge branch exits, the disconnection feedback of the discharge control switch is received, and the arrival time of the disconnection feedback is taken as the retest zero point tr. The start and end times [Ta, Tb] of the aforementioned residual voltage jump-back window relative to the auxiliary contact position change edge t0 are read, where Ta=ta-t0, Tb=tb-t0, and tr is used as the new time reference to map the residual voltage jump-back window into the retest observation window [tr+Ta, tr+Tb].

[0065] Using the same sampling frequency as when generating the residual voltage bounce window, the high-voltage live display signal and the low-voltage control bus signal are re-acquired within the first retest duration before tr and the second retest duration after tr, respectively, to obtain the retested high-voltage live display residual voltage sequence UH′(ti) and the retested low-voltage control bus fluctuation sequence UL′(ti). The first and second retest durations should cover the retest observation window; for example, the first retest duration is 100ms and the second retest duration is 800ms.

[0066] The stable interval before the tr test is selected as the reference interval, for example, the interval from 80ms to 20ms before tr test. The steady-state values ​​UH0′ and UL0′ of the high-voltage and low-voltage tests are calculated respectively. If there is an abrupt change in the discharge control switch or a sudden change in the low-voltage bus within this interval, the stable interval is shifted forward until the signal variance within this interval is lower than the preset variance limit. Subsequently, offset elimination is performed to obtain the high-voltage offset sequence ΔUH′(ti) = UH′(ti) - UH0′ and the low-voltage offset sequence ΔUL′(ti) = UL′(ti) - UL0′.

[0067] For the high-voltage side, search for local peak values ​​of the retested high-voltage offset sequence ΔUH′(ti) within the retest observation window [tr+Ta, tr+Tb]. If there are no valid local peak values ​​with an absolute amplitude greater than the high-voltage recovery threshold θH within the retest observation window, it is determined that the high-voltage live display residual voltage sequence has exited the residual voltage jump-back window; if there are still valid local peak values ​​with an absolute amplitude greater than θH, and the peak value is located within the retest observation window, it is determined that the high-voltage residual voltage is still within the original reverse injection residual voltage jump-back time range, and the prohibition on closing is not lifted.

[0068] The high-voltage recovery threshold θH is determined adaptively. θH is determined based on the high-voltage peak amplitude |AHP| during the previous false blocking determination, the high-voltage noise standard deviation σH in the steady-state range before the displacement change, and the allowable residual voltage error EH of the live display device. Specifically, θH can be calculated as: θH = min{EH, max(3σH, 0.1|AHP|)}; where 3σH is used to cover normal sampling noise, avoiding misinterpreting noise peaks as residual voltage rebound; 0.1|AHP| indicates that the retested residual voltage needs to be attenuated to below 10% of the original abnormal peak value, used to confirm that the backflow residual voltage has been significantly released; EH is the upper limit of the allowable residual voltage error of the live display device, used to prevent the threshold from being relaxed due to an excessively large original abnormal peak value. If 3σH is greater than EH, it indicates that the on-site high-voltage sampling noise has exceeded the allowable residual voltage error. In this case, the threshold is not used to lift the prohibition; instead, a sampling noise exceeding limit warning is generated, and the prohibition on closing continues. This avoids misjudging the disappearance of residual voltage when detection accuracy is insufficient.

[0069] For the low-voltage side, the maximum absolute fluctuation value ULmax′ of the retested low-voltage offset sequence ΔUL′(ti) is calculated within the retest observation window and its subsequent delay interval. The subsequent delay interval can be 2 to 3 power frequency cycles to cover the short-term recovery oscillation of the low-voltage DC power supply module or control power module. When ULmax′ is lower than the low-voltage recovery threshold θL, and this state continues for a preset recovery confirmation time, it is determined that the low-voltage control bus fluctuation sequence is lower than the recovery threshold.

[0070] The low-voltage recovery threshold θL is determined adaptively. θL is determined based on the rated voltage UN of the low-voltage control bus, the standard deviation σL of the low-voltage noise in the steady-state range before the displacement change, and the low-voltage reverse peak amplitude |ALR| at the time of the previous false blocking determination. Specifically, θL = min{0.05UN, max(3σL, 0.01UN, 0.15|ALR|)}; where 3σL is used to adapt to the on-site sampling noise; 0.01UN is used to ensure the recovery threshold is not lower than the normal ripple level of the control bus, avoiding prolonged inability to recover due to normal ripple; 0.15|ALR| is used to confirm that the abnormal low-voltage fluctuation has attenuated to below 15% of the original abnormal amplitude; and 0.05UN serves as a safety upper limit to ensure that the prohibition is not prematurely lifted when significant fluctuations still exist in the low-voltage bus. If 3σL is greater than 0.05UN, it indicates that the low-voltage sampling noise or bus ripple has exceeded the allowable recovery judgment range, the prohibition is not lifted, and a low-voltage fluctuation exceeding limit warning is output.

[0071] Clear the high-voltage reclosing prohibition sign and false interlock sign when the following conditions are simultaneously confirmed: the high-voltage live display residual voltage sequence has exited the residual voltage return window; the low-voltage control bus fluctuation sequence is lower than the low-voltage recovery threshold θL; the discharge control switch is in the disconnected feedback state; the target high-voltage switch main circuit current is still lower than the no-load threshold; there are no grounding switch interlocks, cabinet door interlocks, protection trip interlocks, current sampling abnormalities, or communication interruption abnormalities.

[0072] After clearing the prohibition sign, restore the permission signal to the closing permission circuit of the target high-voltage switch and read the operation type of the original operation command. If the original operation command was a closing command and the command was not revoked by the operator, then output the closing execution command; if the original operation command was a power restoration command, then execute the connection of the target high-voltage switch and the target low-voltage switch in sequence according to the preset power restoration order; if the original operation command has been revoked or the preset validity time has expired, then the operation command will no longer be executed, and only the pseudo-blocking restoration end event will be recorded.

[0073] It should be noted that the recovery threshold is not a fixed empirical value, but is adaptively determined by combining the original abnormal amplitude, the on-site noise level and the equipment's allowable error. This ensures that the circuit can be closed accidentally before the backflow residual pressure is released, and that the equipment cannot be restored to operation for a long time due to normal ripple or sampling noise.

[0074] Example 2, please refer to Figure 2 As shown, the high and low voltage switchgear control system described in this embodiment includes: The instruction parsing and topology association module obtains the operation instructions of the target switchgear and determines the target high-voltage switch and the target low-voltage switch connected to the same transformer based on the operation instructions. The residual voltage rebound window generation module acquires the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence after the auxiliary contact of the target high-voltage switch undergoes a position change, and generates a residual voltage rebound window based on the first reverse peak time of the two. The same-source crosstalk fingerprint generation module calculates the peak interval, attenuation slope ratio and polarity correspondence between the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence within the residual voltage bounce window, and generates the same-source crosstalk fingerprint. The discharge interlocking control module determines that the current interlocking signal is a false interlocking signal caused by reverse residual voltage when the same source crosstalk fingerprint meets the preset crosstalk condition and the target high voltage switch main circuit current is lower than the no-load threshold. Based on the false interlocking signal, it controls the target low voltage switch to connect to the preset discharge branch and prohibits the target high voltage switch from closing again during the discharge period. The recovery and retesting module will release the prohibition and execute the operation command when the re-acquired high-voltage live display residual voltage sequence exits the residual voltage jump-back window and the low-voltage control bus fluctuation sequence is lower than the recovery threshold.

[0075] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A control method for high and low voltage switchgear, characterized in that, include: Obtain the operation instructions of the target switchgear, and determine the target high-voltage switch and the target low-voltage switch connected to the same transformer based on the operation instructions; After the auxiliary contact of the target high-voltage switch undergoes a displacement change, the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence are collected, and a residual voltage return window is generated based on the first reverse peak time of the two. Within the residual voltage bounce window, the peak interval, attenuation slope ratio, and polarity correspondence between the high-voltage live display residual voltage sequence and the low-voltage control bus fluctuation sequence are calculated to generate a co-source crosstalk fingerprint. When the same source crosstalk fingerprint meets the preset crosstalk condition and the target high voltage switch main circuit current is lower than the no-load threshold, it is determined that the current blocking signal is a false blocking signal caused by reverse residual voltage. According to the false blocking signal, the target low voltage switch is controlled to connect to the preset discharge branch, and the target high voltage switch is prohibited from closing again during the discharge period. When the re-acquired high-voltage live display residual voltage sequence exits the residual voltage jump-back window, and the low-voltage control bus fluctuation sequence is below the recovery threshold, the prohibition is lifted and the operation command is executed.

2. The high and low voltage switchgear control method according to claim 1, characterized in that, Identifying the target high-voltage switch and the target low-voltage switch includes: Query the switchgear topology configuration table based on the target device number in the operation instruction to determine the voltage level and transformer number of the target device. When the target equipment is a high-voltage side equipment, the secondary low-voltage incoming switch is retrieved by the transformer number and used as the target low-voltage switch. When the target equipment is a low-voltage side device, the primary high-voltage load switch or high-voltage incoming switch is retrieved in reverse using the transformer number to which it belongs as the target high-voltage switch.

3. The high and low voltage switchgear control method according to claim 2, characterized in that, Generating a residual pressure bounce window includes: The change edge of the auxiliary contact of the target high-voltage switch is used as the synchronization zero point, and the high-voltage energized display residual voltage sequence and low-voltage control bus fluctuation sequence are latched from the cyclic buffer within the corresponding time period before and after the change edge. Offset elimination was performed based on the steady-state value before the displacement change, and the polarity of the low-voltage control bus fluctuation sequence after offset elimination was reversed. In the low-voltage control bus fluctuation sequence after polarity reversal mapping, the first reverse peak moment with the smallest distance from the first peak moment of the high-voltage live display residual voltage sequence is determined, and the residual voltage rebound window is generated by extending the time period from the synchronization zero point to the first reverse peak moment.

4. The high and low voltage switchgear control method according to claim 1, characterized in that, The determination of the first peak time and the first reverse peak time includes: In the high-voltage live display residual voltage sequence after offset elimination, the local peak point that appears earliest after the synchronization zero point and whose amplitude is greater than the preset effective residual voltage amplitude is determined as the first peak point of high voltage. In the low-voltage control bus fluctuation sequence after polarity reversal mapping, local peaks with amplitudes greater than the preset effective amplitude of low-voltage fluctuations are taken as candidate points for reverse peaks. Calculate the time distance between each candidate reverse peak point and the first peak point of the high voltage, and determine the candidate reverse peak point with the smallest time distance as the first reverse peak point.

5. The high and low voltage switchgear control method according to claim 1, characterized in that, The generation of homologous crosstalk fingerprints includes: Within the residual pressure rebound window, the high-pressure peak point and the low-pressure reverse peak point are determined respectively, and the peak interval is calculated based on the peak times of the two. Starting from the high-pressure peak point and the low-pressure reverse peak point respectively, find the sampling points that attenuate to the corresponding peak value by a preset ratio, and calculate the attenuation slope ratio between the high-pressure residual voltage attenuation slope and the low-pressure fluctuation attenuation slope. Based on the amplitude of the high-voltage peak point, the reverse mapping amplitude of the low-voltage reverse peak point, and the amplitude of the low-voltage reverse peak point in the original low-voltage control bus fluctuation sequence, the polarity correspondence is determined, and the same-source crosstalk fingerprint is formed by the peak interval, attenuation slope ratio, and polarity correspondence.

6. The high and low voltage switchgear control method according to claim 1, characterized in that, Determining whether the current blocking signal is a false blocking signal includes: When the peak interval in the same-origin crosstalk fingerprint is less than or equal to the peak interval threshold, the attenuation slope ratio is within the preset slope ratio range, and the polarity correspondence is reverse same-origin, the same-origin crosstalk fingerprint is determined to meet the preset crosstalk condition. Within the preset current confirmation interval after the residual pressure return window ends, calculate the effective value of the three-phase main circuit current of the target high-voltage switch, and take the maximum value among the three-phase current effective values ​​as the main circuit confirmation current. When the main circuit confirms that the current is lower than the no-load threshold, and the current blocking signal comes from the live display blocking circuit or the closing permission blocking circuit, the current blocking signal is determined to be a false blocking signal caused by the reverse residual voltage.

7. The high and low voltage switchgear control method according to claim 6, characterized in that, Controlling the target low-voltage switch to connect to the preset discharge branch based on the false blocking signal includes: Based on the target low-voltage switch number and the corresponding transformer number associated with the false blocking signal, it is confirmed that the target low-voltage switch and the target high-voltage switch are connected to the same transformer. When the target low-voltage switch is in the open position and the low-voltage bus voltage is lower than the preset safe access voltage, the control bleed control switch is closed, so that the preset bleed branch including the bleed resistor is connected to the low-voltage bus corresponding to the target low-voltage switch. The discharge start time is recorded based on the closing feedback of the discharge control switch. If no closing feedback is received within the preset feedback time, the target high-voltage switch remains in the prohibited closing state.

8. The high and low voltage switchgear control method according to claim 1, characterized in that, The process of determining whether to exit the residual voltage return window for a high-voltage live display residual voltage sequence includes: The zero point of the retest is taken as the disconnection feedback moment of the discharge control switch, and the start and end times of the original residual voltage jump window relative to the position change edge of the auxiliary contact are mapped to the retest time axis to obtain the retest observation window. The high-voltage live display signal in the observation window of the retest was reacquired and offset was eliminated based on the stable interval before the retest zero point to obtain the retest high-voltage offset sequence. When there is no effective local peak value with an absolute amplitude greater than the high voltage recovery threshold within the retest observation window, it is determined that the high voltage live display residual voltage sequence exits the residual voltage jump window.

9. The high and low voltage switchgear control method according to claim 8, characterized in that, The process of lifting the restriction and executing the operation instructions includes: The low-voltage recovery threshold is adaptively determined based on the rated voltage of the low-voltage control bus, the standard deviation of the low-voltage noise before the displacement change, and the amplitude of the previous low-voltage reverse peak value. The maximum absolute value of the retested low-voltage fluctuation is judged within the retest observation window and its subsequent delay interval to see if it is lower than the low-voltage recovery threshold. When the high-voltage live display residual voltage sequence exits the residual voltage return window, the low-voltage control bus fluctuation sequence is lower than the low-voltage recovery threshold, the discharge control switch is in the disconnected feedback state and there are no other blocking abnormalities, clear the high-voltage reclosing prohibition sign and the false blocking sign. If the original operation command has not been revoked and the preset effective time has not been exceeded, restore the closing permission signal of the target high-voltage switch and execute the operation command.

10. A high- and low-voltage switchgear control system, used to implement the high- and low-voltage switchgear control method according to any one of claims 1-9, characterized in that, include: The module includes an instruction parsing and topology association module, a residual pressure bounce window generation module, a homogeneous crosstalk fingerprint generation module, a discharge interlocking control module, and a recovery and retesting module.

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