Double-side voltage synchronous sampling switch device for loop closing operation of power distribution network and use method of double-side voltage synchronous sampling switch device

Abstract

The invention discloses a double-side voltage synchronous sampling switch device for loop closing operation of a power distribution network and a use method of the double-side voltage synchronous sampling switch device, and relates to the technical field of power system power distribution network operation control. Extracting a robust baseline and robust dispersion of the annular phase angle difference sequence based on the phase angle; calculating a single-phase peak cluster saliency and a linkage amount by combining a double-side voltage amplitude ratio, and generating a continuous pollution weight; carrying out weighted aggregation to obtain a credible phase angle difference and a credible pressure difference; extrapolating a credible phase angle difference in combination with the frequency difference, constructing a cost function, and solving the optimal switching-on delay; and finally, determining the closing feasibility according to the cost function minimum value and the continuous pollution weight, and generating a closing permission instruction. According to the method, abnormal phase angle fluctuation caused by high-humidity dirt can be effectively identified and inhibited, accidental closed loop locking and failure caused by misjudgment of measurement abrupt change as system asynchronism are avoided, and the safety consistency of closed loop operation of the power distribution network is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of power system distribution network operation control technology, and in particular to a dual-sided voltage synchronous sampling switch device for distribution network loop closing operation and its usage method. Background Technology

[0002] In daily operation, distribution network sectionalizing switches and tie switches often undergo loop-closing operations to achieve load transfer and power restoration. The core of this operation is to ensure that the electrical parameters on both sides of the circuit breaker are consistent before closing, thereby avoiding inrush current and equipment damage. In actual engineering, in high-humidity and polluted environments, a film of polluted water easily forms on the outer surface of the switch poles on distribution poles. This causes the equivalent admittance state of the voltage sampling link to jump with the degree of humidity, and even intermittent conduction. This transient change in the equivalent impedance and phase delay of the measurement link will cause the phase angle difference of a certain phase in the three-phase phase angle difference sequence calculated by the voltage synchronous sampling channel on both sides of the switch to suddenly increase in a short period of time and exhibit abnormal fluctuations in a localized cluster.

[0003] Existing technologies typically rely on monitoring and control devices to collect system voltages on both sides of the circuit breaker's incoming and outgoing lines in real time and compare their amplitudes and phase angles. The controller then uses fixed judgment thresholds to determine whether the closing conditions are met. However, this logic, which relies primarily on rigid judgments based on fixed thresholds, struggles to identify and handle phase angle anomalies caused by admittance transitions on highly humid and contaminated insulation surfaces. When a transient increase in the phase angle difference of a phase occurs, existing devices are prone to misinterpreting the abrupt change in the phase response of the measurement channel as a genuine electrical asynchrony in the system. Consequently, even when the voltage amplitudes on both sides are similar, intermittent asynchronous blocking or closing failures occur over a long period, severely impacting the availability and safety consistency of distribution network loop-closing operations under complex environmental conditions. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies, such as the inability to identify and process anomalous phase angle fluctuations caused by admittance transitions on highly humid and contaminated insulating surfaces, which easily lead to misjudging sudden changes in the phase response of the measurement channel as actual electrical asynchrony in the system, resulting in occasional blocking and failure of loop-closing operations. Therefore, this invention proposes a dual-sided voltage synchronization sampling switch device and its usage method for loop-closing operations in distribution networks.

[0005] To address the problems existing in the prior art, the present invention adopts the following technical solution: A method for using a dual-sided voltage synchronous sampling switch for loop closing operation in a distribution network includes: S1. Collect the three-phase voltages on both sides of the circuit breaker and perform phasor estimation to obtain the phase voltage amplitude, phase angle and frequency difference between the two sides. S2. Calculate the ring phase angle difference sequence for each phase based on the phase angle, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence; S3. Based on the robust baseline, robust dispersion and voltage amplitude ratio of the ring phase angle difference sequence, calculate the significance and linkage of single-phase spike clusters, and generate the continuous pollution weight of each phase. S4. Based on the continuous pollution weight, the robust baseline is weighted and aggregated to obtain the reliable phase angle difference, and the voltage amplitude ratio on both sides is aggregated to obtain the reliable voltage difference. S5. Based on the frequency difference between the two sides, extrapolate the reliable phase angle difference in a preset future time window, construct a cost function by combining the current reliable voltage difference and the extrapolated reliable phase angle difference, and solve for the optimal closing delay. S6. Determine the closing feasibility based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and generate a closing permission instruction based on the closing feasibility.

[0006] Preferably, the three-phase voltages on both sides of the circuit breaker are collected and phasor estimation is performed to obtain the phase voltage amplitude, phase angle, and frequency difference between the two sides, including: The three-phase voltages on the first and second sides of the circuit breaker are sampled synchronously to obtain the three-phase voltage sequence on the first side and the three-phase voltage sequence on the second side. Phasor estimation is performed within the set nearest window to obtain the corresponding first-side phase voltage magnitude and first-side phase angle, as well as the second-side phase voltage magnitude and second-side phase angle. Calculate the difference between the first-side frequency and the second-side frequency, and take the median of the difference within a set nearest window to obtain the bilateral frequency difference.

[0007] Preferably, the ring phase angle difference sequence for each phase is calculated based on the phase angle, and the robust baseline and robust dispersion of the ring phase angle difference sequence are extracted, including: The difference between the first phase angle and the second phase angle is mapped in a ring to obtain the ring phase angle difference sequence of each phase. The ring mapping is to map the phase angle difference to the range of negative to positive pi. Within the set nearest window, the median of the ring phase difference sequence is used as the robust baseline, and the median of the absolute value of the difference between the ring phase difference and the robust baseline is calculated to obtain the robust dispersion.

[0008] Preferably, the significance and linkage of single-phase spike clusters are calculated based on the robust baseline, robust dispersion, and voltage amplitude ratio of the ring phase angle difference sequence, including: Within the set nearest window, the median of the ratio of the absolute value of the difference between the ring phase angle difference and the robust baseline to the robust dispersion is used as the significance of the single-phase peak cluster. Calculate the logarithm of the voltage amplitude ratio between corresponding phases on the first and second sides of the circuit breaker; The linkage quantity is obtained by dividing the covariance of the logarithm of the ring phase angle difference sequence and the voltage amplitude ratio within a set nearest window by the variance of the logarithm within the set nearest window.

[0009] Preferably, generating the continuous pollution weights for each phase includes: The median of the significance of the single-phase peak clusters in the three phases was used as the adaptive significance scale. The median of the absolute values ​​of the three-phase linkage quantities is used as the linkage adaptive scale. For each phase, the square of the ratio of the single-phase peak cluster significance to the significance adaptive scale is used as the first penalty term; For each phase, the square of the ratio of the absolute value of the linkage quantity to the linkage adaptive scale is used as the second penalty term; For each phase, the first penalty term, the second penalty term, and 1 are summed, and the reciprocal of the sum is taken to obtain the continuous pollution weight of each phase.

[0010] Preferably, a reliable phase angle difference is obtained by weighting and aggregating robust baselines based on continuous pollution weights, and a reliable voltage difference is obtained by aggregating the voltage amplitude ratios on both sides, including: The continuous pollution weight of each phase is used as the amplitude, and the corresponding robust baseline is used as the phase angle to construct the complex quantity of each phase. The phase angle is extracted after summing the complex quantities of the three phases to obtain the reliable phase angle difference; Calculate the absolute value of the logarithm of the three-phase voltage amplitude ratio, and take the median of this absolute value among the three phases as the reliable voltage difference.

[0011] Preferably, based on the frequency difference between the two sides, the reliable phase angle difference is extrapolated into the future time window. A cost function is constructed by combining the current reliable voltage difference and the extrapolated reliable phase angle difference to solve for the optimal closing delay, including: Within a preset future time window, calculate the product of twice the value of pi, the frequency difference between the two sides, and the extrapolated time span. Add the product to the current reliable phase angle difference to obtain the predicted phase angle difference, and map the predicted phase angle difference to the range of negative to positive pi. Within the nearest window, a reliable pressure difference sequence is calculated for each sampling time. The absolute value of the difference between the reliable pressure difference sequence and its median is calculated, and the median of the absolute value of the difference within the nearest window is taken as the pressure difference dispersion scale. Within the nearest window, a reliable phase difference sequence is calculated for each sampling time. The difference between the reliable phase difference sequence and its median is calculated. The absolute value of the difference is then obtained by performing a circular mapping. The median of the obtained absolute value within the nearest window is used as the phase difference dispersion scale. The cost function is constructed by adding the square of the ratio of the current reliable pressure difference to the pressure difference dispersion scale, and the square of the ratio of the absolute value of the predicted phase angle difference to the phase angle difference dispersion scale. The extrapolated time span within the preset future time window is traversed, and the extrapolated time span that minimizes the cost function is taken as the optimal closing delay.

[0012] Preferably, the closing feasibility is determined based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and a closing permission instruction is generated based on the closing feasibility, including: Calculate the average value of the continuous pollution weights of the three phases, and multiply this average value by a power of the natural constant with the negative of the minimum cost function as the exponent to obtain the current closing feasibility. Within a window containing the current time and the preset number of historical sampling points, determine whether the closing feasibility at the current time is at its maximum value; if so, output a closing permission command that allows closing and control the circuit breaker to issue a closing pulse after the optimal closing delay; if not, maintain the blocked state.

[0013] To address the aforementioned problems, the present invention also provides a dual-sided voltage synchronous sampling switch device for distribution network loop closing operation, the device comprising: The parameter extraction module is used to collect the three-phase voltages on both sides of the circuit breaker and perform phasor estimation to obtain the phase voltage amplitude, phase angle and frequency difference between the two sides. The baseline extraction module is used to calculate the ring phase angle difference sequence for each phase based on the phase angle, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence. The anomaly assessment module is used to calculate the significance and linkage of single-phase spike clusters based on the robust baseline, robust dispersion and voltage amplitude ratio of the ring phase angle difference sequence, and to generate the continuous pollution weight of each phase. The weighted aggregation module is used to perform weighted aggregation of robust baselines based on continuous contamination weights to obtain a reliable phase angle difference, and to aggregate the voltage amplitude ratios on both sides to obtain a reliable voltage difference. The cost calculation module is used to extrapolate the reliable phase angle difference within a preset future time window based on the frequency difference between the two sides. It constructs a cost function by combining the current reliable pressure difference with the extrapolated reliable phase angle difference and solves the optimal closing delay. The closing determination module is used to determine the closing feasibility based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and to generate a closing permission instruction based on the closing feasibility.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention calculates the robust baseline and dispersion of the phase angle difference sequence, derives the significance and linkage of single-phase spike clusters by combining the two-sided voltage amplitude ratio, and then generates the continuous pollution weight of each phase. Based on this, the robust baseline is weighted and aggregated to obtain a reliable phase angle difference. It can adaptively identify and continuously suppress the abnormal increase in single-phase phase angle difference caused by the admittance transition of the insulation surface and intermittent conduction under high humidity and pollution environment. By automatically weakening the weight interference of the polluted phase, it effectively avoids misjudging the transient phase response change of the measurement channel as the actual electrical asynchrony of the system, fully ensuring the robustness and accuracy of the phase angle difference data, overcoming the defects of long-term occasional blocking or closing failure in the loop operation, and significantly improving the availability and safety consistency of the equipment in complex environments.

[0015] 2. In this invention, the reliable phase angle difference is extrapolated within a preset future time window using the frequency difference between the two sides. This difference is then combined with the reliable voltage difference to construct a cost function to solve for the optimal closing delay. The closing feasibility is determined based on the minimum value of the cost function and the continuous pollution weight to output the closing command. This abandons the traditional logic of relying on fixed judgment boundaries for hard interception. Instead, it transforms amplitude inconsistency and phase inconsistency into dimensionless deviation degrees for comprehensive dynamic measurement. This allows for precise traversal and locking of the optimal closing time with the lowest risk of inrush current. Combined with the maximum value optimization strategy within the judgment window, this ensures that the circuit breaker only performs actions at the optimal time when the sampled data is most reliable and the overall mismatch degree is lowest. This avoids the risk of malfunction under abnormal operating conditions and comprehensively ensures the safety and stability of the distribution network's loop-closing operation. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 A flowchart illustrating the usage method of a dual-sided voltage synchronous sampling switch device for loop closing operation in a power distribution network, provided by the present invention. Figure 2 A functional block diagram of a dual-sided voltage synchronous sampling switch device for distribution network loop closing operation provided by the present invention; Figure 3 This is a schematic diagram of the lateral displacement profile and adjacent differential amplitudes provided by the present invention. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Example: This example provides a method for using a dual-sided voltage synchronous sampling switch device for loop closing operation in a distribution network. See [link to example]. Figure 1 Specifically, including: S1. Collect the three-phase voltages on both sides of the circuit breaker and perform phasor estimation to obtain the phase voltage amplitude, phase angle and frequency difference between the two sides. S2. Calculate the ring phase angle difference sequence for each phase based on the phase angle, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence; S3. Based on the robust baseline, robust dispersion and voltage amplitude ratio of the ring phase angle difference sequence, calculate the significance and linkage of single-phase spike clusters, and generate the continuous pollution weight of each phase. S4. Based on the continuous pollution weight, the robust baseline is weighted and aggregated to obtain the reliable phase angle difference, and the voltage amplitude ratio on both sides is aggregated to obtain the reliable voltage difference. S5. Based on the frequency difference between the two sides, extrapolate the reliable phase angle difference in a preset future time window, construct a cost function by combining the current reliable voltage difference and the extrapolated reliable phase angle difference, and solve for the optimal closing delay. S6. Determine the closing feasibility based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and generate a closing permission instruction based on the closing feasibility.

[0019] In an embodiment of the present invention, the three-phase voltages on both sides of the circuit breaker are collected and phasor estimation is performed to obtain the phase voltage amplitudes, phase angles, and frequency differences on both sides, specifically including: When synchronously sampling the three-phase voltages on the first and second sides of the circuit breaker, a high-precision synchronous sampling chip is used as the core component of the dual-side voltage acquisition unit. This sampling chip has multi-channel synchronous sampling capability, and can simultaneously acquire the phase voltages of phases A, B, and C on the first side of the circuit breaker and phases A, B, and C on the second side. The synchronous sampling and time base unit provide a unified synchronous trigger signal, which is obtained by dividing a 10 MHz reference clock by 2,000, resulting in a 5 kHz frequency. This ensures that the six sampling channels on the first and second sides start sampling at the same time. During sampling, a shielded cable connects the circuit breaker's input and output terminals to the sampling chip's input terminal. The outer layer of the shielded cable is grounded to suppress electromagnetic interference and avoid sampling signal distortion. The sampling chip then collects the voltages... After the analog voltage signal is converted into a 16-bit digital signal, it is transmitted to the phasor calculation unit. Data verification is performed using a combination of amplitude and rate of change thresholds to remove abnormal sampling points that exceed the normal voltage range or voltage mutation rate limits. This yields the first-side three-phase voltage sequence and the second-side three-phase voltage sequence. Each sampling time number corresponds to a 200-microsecond sampling interval. When performing phasor estimation within a set nearest window, the length N of the nearest window is set to 200 sampling points, corresponding to a time length of 40 milliseconds. This window length covers two power frequency cycles of the distribution network, effectively smoothing random interference during the sampling process and improving the stability of phasor estimation. Phasor estimation uses a fundamental discrete Fourier transform method based on a sliding window, and the calculation formula is as follows: ;

[0020] in, Used to distinguish between the first and second sides of a circuit breaker. Taking 1 indicates the first side. Taking 2 indicates the second side. Used to distinguish three phases When A is chosen, it represents phase A. When B is selected, it represents phase B. When C is chosen, it represents phase C. Indicates the current sampling time sequence number. Indicates the current time Down side The voltage complex of the phase. Indicates sampling time i side Phase voltage sampling value, This represents the total number of sampling points within the most recent window, divided by 2. These are normalization coefficients used to restore the Discrete Fourier Transform result to the actual voltage amplitude, eliminating the influence of the window length on the calculation result. This indicates the rated power frequency of the distribution network, with a value of 50 Hz. The sampling frequency is 5 kHz, j represents the imaginary unit, and the exponent term is used to convert the sampled signal to the fundamental frequency domain, filtering out higher harmonic components to ensure the accuracy of phasor calculation. The result is obtained through the above formula. side After obtaining the phase voltage complex, take the modulus of the complex to obtain side The phase voltage amplitude of a phase is calculated using the following formula: ;

[0021] in Indicates the current time Down side The phase voltage amplitude of the phase is obtained by taking the argument of the complex phase. side The phase angle of a phase is calculated using the following formula: ;

[0022] in Indicates the current time Down side The phase angles of the phases are obtained by the above processing to obtain the corresponding first-side phase voltage amplitude and first-side phase angle, as well as the second-side phase voltage amplitude and second-side phase angle.

[0023] It should be noted that the synchronous sampling chip in this embodiment is a dedicated integrated circuit with multi-channel analog signal synchronous acquisition and analog-to-digital conversion functions. Its core function is to simultaneously acquire the analog signals of the three-phase voltages on both sides of the circuit breaker and convert them into digital signals for subsequent processing. The high-precision synchronous sampling chip selected in this embodiment can achieve synchronous acquisition of six signals, ensuring the time consistency of voltage sampling on both sides. The synchronous trigger signal is a reference signal generated by the synchronous sampling and time base unit to control the sampling chip to start sampling. Its frequency is consistent with the sampling frequency. In this embodiment, it is obtained by frequency division of a 10MHz reference clock to ensure that all sampling channels on the first and second sides of the circuit breaker start sampling at the same time, avoiding sampling timing deviation. The fundamental discrete Fourier transform is a frequency domain analysis method used to extract the fundamental component from the sampled signal. In this embodiment, this method is used for phasor estimation. The core purpose is to filter out high-order harmonic interference in the sampled signal and ensure the accuracy of voltage phasor calculation.

[0024] It should be noted that the voltage complex phasor is a complex number used to simultaneously characterize the voltage amplitude and phase angle. Its magnitude corresponds to the voltage amplitude, and its argument corresponds to the voltage phase angle. It is the core output quantity of phasor estimation. The nearest window refers to a continuous sampling time period containing a set number of sampling points, with the current sampling time as the endpoint. In this embodiment, the window length is set to 200 sampling points, corresponding to a duration of 40ms. Its function is to smooth out random interference in the sampling process and improve the stability of phasor estimation through the superposition of multiple sampling points. The rated power frequency refers to the standard frequency when the distribution network is operating normally. In this embodiment, the value is taken as 50Hz, which conforms to the rated operating frequency standard of my country's distribution network. The phase voltage amplitude refers to the effective value of the voltage signal, which is obtained by taking the modulus of the voltage complex phasor. It is used to characterize the strength of the voltage and is the basis for subsequent voltage amplitude ratio calculation. The phase angle refers to the phase angle of the voltage signal, which is obtained by taking the argument of the voltage complex phasor. The value range is 0 to 2π, which is used to characterize the phase state of the voltage signal.

[0025] Frequency calculations are performed on the phase angles of each phase on the first and second sides obtained from the aforementioned phasor estimation. The instantaneous frequency of each phase is calculated by the change in phase angle between adjacent sampling times. The calculation formula is as follows: ;

[0026] in For the current moment Down side The instantaneous frequency of the phase, For the current moment Down side The phase angle of the phase, For the current moment Down side The phase angle at the previous sampling time. Using the sampling period as a guide, this formula solves for the frequency based on the time-domain variation characteristics of the phase angle, accurately reflecting the fundamental frequency variation of the voltage signal. After calculating the instantaneous three-phase frequencies on the first side, the median of the three-phase values ​​is taken to obtain the robust frequency on the first side. After calculating the instantaneous three-phase frequencies on the second side, the median of the three-phase values ​​is taken to obtain the robust frequency on the second side. Median processing can eliminate the interference of single-phase abnormal data on the overall frequency calculation, improving the output stability of the frequencies on both sides. The difference between the robust frequencies on the first side and the robust frequencies on the second side is calculated to obtain the frequency difference at a single moment. Within the set nearest window, the frequency difference at all sampling moments is extracted and formed into a frequency difference sequence. Median processing is performed on this sequence to obtain the frequency difference between the two sides. Median processing of the frequency difference sequence can effectively suppress the frequency fluctuations caused by sampling noise and single-phase phase angle anomalies, ensuring the robustness and reliability of the frequency difference between the two sides, and providing a stable frequency reference for the subsequent extrapolation calculation of the reliable phase angle difference.

[0027] It should be noted that the instantaneous frequency in this embodiment is a real-time frequency value obtained by solving the phase angle change at adjacent sampling times, which can intuitively reflect the fundamental frequency change state of the voltage signal; the sampling period is the time interval between two adjacent samplings, which is the reciprocal of the set sampling frequency and is the basic time parameter for frequency calculation; the robust frequency is the frequency value obtained by taking the median of the instantaneous frequencies of the three phases on one side, which can eliminate the calculation deviation caused by single-phase data anomalies and improve the reliability of the single-side frequency output; the frequency difference sequence is a data set composed of the single-time frequency differences corresponding to all sampling times within the most recent window; the two-side frequency difference refers to the frequency difference on the first side of the switch. The difference between the electrical frequencies corresponding to the voltage phasors formed on the second side and the voltage phasors formed on the third side is used to characterize the relative drift speed of the voltage phases on both sides of the closing point over time. When the speed control, inverter control or load disturbance of the power supply or equivalent power supply on both sides is inconsistent, the periodic change rate of the voltage on both sides will have slight differences, which will cause the phase angle difference on both sides to continuously increase or decrease over time and affect the prediction of the closing window. The frequency difference between the two sides is estimated by synchronously sampling the three-phase voltages on both sides to obtain the frequency of the first side and the frequency of the second side respectively, and the difference is obtained by robustly statistically analyzing the difference within the set nearest window to reduce the influence of instantaneous noise and measurement jitter on the frequency difference estimation.

[0028] In embodiments of the present invention, the ring phase angle difference sequence for each phase is calculated based on the phase angle, and the robust baseline and robust dispersion of the ring phase angle difference sequence are extracted, specifically including: After calculating the difference between the first-side phase angle and the second-side phase angle of each phase, a ring mapping process is performed to obtain the corresponding ring phase angle difference sequence. The calculation formula for the ring mapping is: ;

[0029] Where i is the sampling time number. Let p be the ring phase angle difference at the i-th sampling time. Let p be the phase angle of the first side at the i-th sampling time. Let be the phase angle of the second side p phase at the i-th sampling time. wrap is a ring mapping operation, which maps the phase angle difference to the range from negative to positive pi, avoiding numerical anomalies caused by phase angle period jumps and ensuring the continuity and consistency of phase angle difference calculation.

[0030] Within the defined nearest window, the median is calculated for each phase ring phase angle difference sequence. The result is used as the robust baseline for that phase ring phase angle difference. The calculation formula is as follows: ;

[0031] in Let `median` be the robust baseline for the p-phase ring phase difference. `median` is used for median calculation. Median calculation effectively removes anomalous data mutations in the ring phase difference sequence, ensuring that the baseline value accurately reflects the steady-state level of the phase difference. Then, the absolute value of the difference between the ring phase difference of each phase and the corresponding robust baseline is calculated point by point. Within the nearest window, the median calculation is performed on this absolute value sequence to obtain the robust dispersion of the p-phase ring phase difference. The calculation formula is: ;

[0032] in The robust dispersion of the p-phase ring phase angle difference is obtained by the above processing, which yields the robust baseline and robust dispersion of the ring phase angle difference for each phase.

[0033] It should be noted that the ring mapping in this embodiment is an operation that constrains the phase angle difference within the range of negative to positive pi, used to eliminate the numerical abrupt change caused by the periodic jump of the phase angle. The ring phase angle difference sequence is a continuous and stable data set formed after ring mapping, which can truly reflect the deviation state of the phase angles on both sides. The robust baseline is the phase angle difference benchmark value obtained based on the median, which can resist the interference of sampling noise and single-phase spike data, accurately characterize the central trend of the phase angle difference. The robust dispersion is a statistic used to measure the degree of fluctuation of the ring phase angle difference sequence, which can objectively reflect the data dispersion characteristics.

[0034] Within the defined nearest window, the absolute value of the difference between the p-phase annular phase angle difference and the corresponding robust baseline is calculated point by point. This absolute value is then ratioed to the p-phase robust dispersion to obtain a normalized deviation sequence. The median of this normalized deviation sequence is then calculated to obtain the single-phase spike cluster significance of the p-phase. The calculation formula is as follows: ;

[0035] Where i is the sampling time number. The significance of the single-phase spike cluster in phase p. Let p be the ring phase angle difference at time i. As a robust baseline for the p-phase ring phase angle difference, The robust dispersion of the p-phase annular phase angle difference is used for normalization. This can eliminate the influence of the difference in the fluctuation level of each phase data on the significance determination. The median calculation can suppress the interference of single-point abnormal deviation, so that the significance of the single-phase peak cluster can accurately reflect the degree of clustered abrupt change in the phase angle difference.

[0036] Calculate the ratio of the voltage amplitude of the first phase to the voltage amplitude of the second phase of the circuit breaker phase by phase, and then obtain the natural logarithm of this ratio. The calculation formula is as follows: ;

[0037] in Let be the logarithm of the voltage amplitude ratio of phase p at time i. Let be the phase voltage amplitude of phase p on the first side at time i. Let p be the phase voltage amplitude of the second side p phase at time i. By using natural logarithm processing, the multiplication and division relationship of the amplitude ratio can be transformed into a linear relationship, reducing the impact of amplitude magnitude changes on subsequent linkage analysis.

[0038] Within the set nearest window, calculate the covariance between the p-phase ring phase angle difference sequence and the voltage amplitude ratio logarithmic sequence. Then, calculate the variance of the voltage amplitude ratio logarithmic sequence within the same window. The ratio of the covariance to the variance yields the p-phase linkage quantity. The calculation formula is as follows: ;

[0039] in denoted as p-phase linkage quantity, cov is the covariance operation, and var is the variance operation. Covariance is used to characterize the degree of linear correlation between two sequences, and variance is used to characterize the degree of dispersion of a single sequence. This ratio operation is equivalent to the calculation of the linear regression slope, which can accurately reflect the linkage characteristics of the ring phase angle difference with the change of voltage amplitude ratio, and provide a quantitative basis for the subsequent generation of pollution weights.

[0040] It should be noted that the normalized deviation sequence in this embodiment is a dimensionless sequence obtained by dividing the absolute deviation of the ring phase angle difference by the robust dispersion, which can realize a unified comparison of the fluctuation degree between different phases; the voltage amplitude ratio is the ratio of the voltage amplitude of the first phase to the voltage amplitude of the second phase at the same time, which is used to characterize the amplitude deviation state of the voltages on both sides.

[0041] It should be noted that the single-phase spike cluster significance is used to characterize the abnormal intensity of a clustered sudden increase in the ring phase angle difference of a certain phase over time under the condition of synchronous sampling of voltage on both sides of the switch. It reflects the degree of disturbance to the phase response when the transient admittance changes of the voltage measurement link or external insulation surface of that phase are caused by environmental factors such as high humidity and pollution. When the polluted water film transitions from weak to strong conduction or intermittent conduction, the equivalent impedance and phase delay of the sampling channel will change abruptly in a short period of time, causing the phase angle difference of that phase to deviate from its robust baseline and exhibit a short-term dense spike shape. The larger the significance, the more concentrated and intense the abrupt change in the phase angle difference of that phase, and the more likely it is to be polluted. Simultaneous judgment of dyeing and testing; the linkage quantity is used to characterize the synchronous correlation strength between the change of the phase angle difference of the phase ring and the change of the voltage amplitude ratio on both sides. It reflects the degree to which the same admittance disturbance or measurement link state change simultaneously affects the phase response and amplitude transmission. When the leakage conduction on the insulation surface is enhanced or the active power loss of the voltage measurement link increases, it will not only cause short-term changes in phase shift, but also cause considerable fluctuations in the logarithm of the amplitude ratio on both sides in the same or opposite direction. The larger the linkage quantity, the stronger the homology between the phase angle difference and the amplitude ratio anomaly, so it can be used to determine that the peak cluster of the phase is more likely to come from channel state disturbance rather than the true phase asynchrony of the system.

[0042] Within the set nearest window, the significance of each single-phase spike cluster is extracted. The median of these three single-phase spike cluster significances is then calculated, and the result is used as the adaptive significance scale. Using the median as the adaptive scale can avoid the interference of abnormal single-phase significance on the overall judgment standard, ensuring the robustness and universality of the scale. At the same time, the linkage quantity of each of the three phases is extracted and its absolute value is taken. The median of these three linkage quantities is then calculated, and the result is used as the linkage adaptive scale. Taking the absolute value of the linkage quantity can eliminate the influence of positive and negative signs on the scale calculation, and the median calculation can resist the interference of abnormal linkage quantities, ensuring that the linkage adaptive scale can reflect the average level of the three-phase linkage characteristics.

[0043] For each phase, the ratio of the single-phase spike cluster significance to the adaptive significance scale is calculated, and then the ratio is squared to obtain the first penalty term. Squaring amplifies the deviation of the single-phase spike cluster significance relative to the scale, giving the most polluted phase a greater penalty weight. Simultaneously, the absolute value of the phase's linkage quantity is ratioed to the linkage adaptive scale, and this ratio is squared to obtain the second penalty term. Similarly, squaring amplifies the deviation of the linkage quantity relative to the scale, strengthening the penalty effect on phases with abnormal linkage. Then, the first penalty term, the second penalty term, and a constant 1 are summed, and the reciprocal of the sum is taken to obtain the continuous pollution weight of the phase. The calculation formula is as follows: ;

[0044] in For the continuous pollution weight of phase p, The significance of the single-phase spike cluster in phase p. For saliency adaptive scaling, For the linkage quantity of phase p, To enable adaptive scaling, the summation constant 1 avoids the calculation failure caused by a denominator of 0 when both penalty terms are 0. Taking the reciprocal allows the phase with the larger penalty term to receive a smaller contamination weight, thereby achieving continuous suppression of the phase contaminated by the single-phase spike cluster, while ensuring that the weight of the uncontaminated phase is maintained at a high level, thus ensuring the reliability of subsequent calculations of the reliable phase angle difference and reliable pressure difference. Among them, single-phase spike cluster contamination refers to the phenomenon in which, during the synchronous sampling and detection of voltage on both sides of the loop switch, only one phase in the three-phase phase angle difference sequence exhibits a dense and clustered spike in phase angle difference within a short period of time. This causes the phase information of that phase to deviate from its normal stable level and mislead subsequent reliable phase angle difference calculation, closing window prediction, and closing permission determination. This contamination usually originates from the transition or intermittent conduction of the admittance state of the contaminated water film on the insulation surface under high humidity and contamination conditions. This causes the equivalent impedance and phase delay of the voltage measurement link to change abruptly within a short period of time, resulting in the single-phase phase angle difference being amplified by transient phase bias, while the phase angle differences of the other two phases remain relatively stable. This forms a single-phase abnormal spike cluster and triggers the risk of occasional blocking or false release during loop detection and synchronization.

[0045] It should be noted that the first penalty term is a penalty measure used to quantify the relative intensity of a single-phase spike cluster anomaly in the toroidal phase angle difference of a certain phase. It is composed of the relative ratio of the significance of the single-phase spike cluster to the adaptive scale of the three-phase significance, reflecting the degree of damage to the reliability of the detection synchronization when the phase angle difference of that phase deviates from the robust baseline and shows a clustered sudden increase. The higher the significance, the larger the first penalty term, indicating that the phase information of that phase is more likely to be contaminated by wet contamination admittance transitions or abrupt changes in the measurement link phase. The second penalty term is a penalty measure used to quantify the degree of co-originating linkage between the phase angle difference anomaly and the bi-lateral voltage amplitude ratio anomaly. It is composed of the relative ratio of the absolute value of the linkage to the adaptive scale of the three-phase linkage, reflecting the degree of damage to the reliability of the detection synchronization when the phase angle difference deviates from the robust baseline and shows a clustered sudden increase. The higher the significance, the larger the first penalty term, indicating that the phase information of that phase is more likely to be contaminated by wet contamination admittance transitions or abrupt changes in the measurement link phase. The degree to which a disturbance in the same channel state causes anomalies in both amplitude and phase transmission is considered. The stronger the linkage, the larger the second penalty term, indicating that the anomaly in that phase is more likely to originate from a change in the channel state rather than a true system asynchrony. The continuous contamination weight of each phase is a reliability coefficient resulting from the combined effect of the first and second penalty terms. It is obtained by taking the reciprocal of the sum of the first and second penalty terms and remains continuously adjustable. The smaller the weight, the less reliable the phase angle difference measured in that phase is, and it will be automatically weakened in subsequent reliable phase angle difference aggregation. The larger the weight, the more stable the phase angle difference and amplitude ratio of that phase are and the closer they are to the true electrical state. This achieves adaptive suppression of single-phase spike cluster contamination and improves the stability of the loop closing criterion.

[0046] In embodiments of the present invention, a reliable phase angle difference is obtained by weighting and aggregating robust baselines based on continuous pollution weights, and a reliable voltage difference is obtained by aggregating the voltage amplitude ratios on both sides, specifically including: Complex quantities are constructed phase-by-phase within a defined recent window. The continuous contamination weight of each phase is used as the amplitude of the complex quantity, and the corresponding robust baseline is used as the phase angle of the complex quantity. The formula for constructing and calculating the complex quantity is as follows: ;

[0047] in, For the complex quantity constructed for phase p, For the continuous pollution weight of phase p, Here, j represents the robust baseline for the p-phase annular phase angle difference, and j is the imaginary unit. This method constructs a complex quantity that can simultaneously carry the suppressive effect of continuous pollution weights and the phase angle reference information of the robust baseline, achieving an organic combination of weights and phase angles, and providing a foundation for subsequent aggregate calculation of credible phase angle differences.

[0048] After constructing the three-phase complex quantities, the complex quantities of phases A, B, and C are summed to obtain the aggregated result of the three-phase complex quantities. The argument of this aggregated result is extracted, and the extracted argument is used as the reliable phase angle difference. The calculation formula is as follows: ;

[0049] in Let be the credible phase angle difference at the current time k, and arg be the argument extraction operation. By summing the three-phase complex quantities and then extracting the argument, the weight of the contaminated phase can be automatically reduced, and the weight of the uncontaminated phase can be fully utilized. This effectively suppresses the interference of single-phase spike clusters on the phase angle difference judgment and ensures the robustness and accuracy of the credible phase angle difference.

[0050] Calculate the ratio of the voltage amplitude of the first phase to the voltage amplitude of the second phase of the circuit breaker phase by phase. Take the natural logarithm of this ratio and then take its absolute value to obtain the absolute value of the logarithm of the voltage amplitude ratio for each phase. The calculation formula is as follows: ;

[0051] in Let be the absolute value of the logarithm of the phase p voltage amplitude at time k. This represents the phase voltage amplitude of phase p on the first side at the current moment. Let p be the phase voltage amplitude of the second side at the current moment. The natural logarithm processing can convert the nonlinear relationship of the amplitude ratio into a linear relationship. Taking the absolute value can eliminate the influence of positive and negative signs on subsequent calculations. After calculating the absolute value of the logarithm of the voltage amplitude ratio of each of the three phases, the median operation is performed on these three values. The median operation can effectively eliminate the interference caused by the amplitude anomaly of a single phase, ensuring that the reliable differential pressure can truly reflect the actual deviation level of the voltage amplitude on both sides, and providing reliable differential pressure parameters for the subsequent solution of the optimal closing delay.

[0052] It should be noted that the reliable phase angle difference refers to the equivalent phase angle difference obtained from the three-phase ring phase angle difference obtained by synchronous sampling on both sides of the closing switch. This is achieved by first extracting a robust baseline for each phase ring phase angle difference and calculating a continuous pollution weight reflecting the degree of pollution, then weighting and aggregating the robust baselines of each phase with the continuous pollution weight. This effectively represents the main component of the voltage phase difference on both sides of the closing point and suppresses the pulling effect of the relative results caused by pollution, thus making the phase angle difference closer to the actual electrical asynchrony level and more suitable for extrapolating the closing window and determining the allowable closing time. The reliable voltage difference is a robust amplitude difference metric constructed to characterize the degree of inconsistency in voltage amplitude on both sides of the closing point. It is based on the logarithm of the voltage amplitude ratio of the corresponding phases on both sides and is robustly aggregated across the three phases. This reduces the impact of single-phase amplitude fluctuations and measurement noise on voltage difference discrimination, enabling the voltage difference result to stably reflect the relative deviation of the voltage amplitude on both sides. Together with the reliable phase angle difference, it is used to construct the closing cost function and determine the optimal closing delay.

[0053] In an embodiment of the present invention, the reliable phase angle difference is extrapolated from the frequency difference on both sides within a preset future time window. A cost function is constructed by combining the current reliable voltage difference with the extrapolated reliable phase angle difference to solve for the optimal closing delay. Specifically, this includes: Phase difference extrapolation is performed within a preset future time window, which is set to one nominal power frequency cycle. The extrapolation time span ranges from zero to the nominal power frequency cycle duration, which is set to twenty milliseconds based on the rated power frequency of the distribution network. Based on the current reliable phase difference and the bilateral frequency difference, the predicted phase difference at different extrapolated times is calculated. First, the product of twice pi, the bilateral frequency difference, and the extrapolation time span is calculated. This product is then added to the current reliable phase difference. Finally, a circular mapping operation is performed on the sum to uniformly map the predicted phase difference to the interval between negative and positive pi. The calculation formula is as follows: ;

[0054] in Let be the predicted phase angle difference corresponding to the extrapolated time span τ at the current time k. `wrap` is a circular mapping operation used to eliminate numerical abrupt changes caused by phase period jumps, ensuring the continuity and stability of the prediction results. Let π be the reliable phase angle difference at the current time k, and let π be the constant pi. Let k be the frequency difference between the two sides at the current time. The extrapolation formula, which extrapolates the phase angle difference within a future time window, relies on the linear relationship between frequency and phase angle to extrapolate the phase angle difference. It can accurately reflect the changing trend of the phase angle difference between the voltages on both sides over time, providing a reliable predictive basis for subsequent closing delay optimization.

[0055] Within a defined nearest window, the pressure difference dispersion scale and phase difference dispersion scale are calculated. The length of this nearest window is consistent with the nearest window used in the aforementioned phasor estimation, frequency difference calculation, and spike cluster identification, and is set to two hundred sampling points, corresponding to a time length of forty milliseconds, to ensure a consistent time base for all statistical operations. The pressure difference dispersion scale is calculated by calculating the reliable pressure difference at each sampling time point-by-point within this nearest window. A reliable pressure difference sequence is formed from the reliable pressure differences at all sampling times. The median of this reliable pressure difference sequence is then obtained by performing a median operation. The median can reflect the central trend of the reliable pressure difference sequence and effectively resist the interference caused by the abnormality of the reliable pressure difference at a single moment. Then, the difference between each value in the reliable pressure difference sequence and the median is calculated point by point, and the absolute value of the difference is taken to obtain the reliable pressure difference deviation absolute value sequence. The median operation is performed on the deviation absolute value sequence, and the operation result is used as the pressure difference dispersion scale. The use of median operation can effectively suppress the interference of abnormal data in the reliable pressure difference sequence and ensure that the pressure difference dispersion scale can truly reflect the actual fluctuation level of the reliable pressure difference, providing a stable pressure difference scale benchmark for the subsequent construction of cost function.

[0056] The phase difference dispersion scale is calculated by calculating the reliable phase difference at each sampling time point by point within the same nearest window. The reliable phase difference sequence is composed of the reliable phase difference at all sampling times. First, the median operation is performed on the reliable phase difference sequence to obtain the median of the reliable phase difference sequence. Then, the difference between each value in the reliable phase difference sequence and the median is calculated point by point. A circular mapping operation is performed on the difference to uniformly map the difference to the range of negative to positive pi, avoiding numerical anomalies caused by periodic jumps in the phase difference and ensuring the continuity of the deviation calculation. Then, the absolute value of the difference after circular mapping is taken to obtain the reliable phase difference deviation absolute value sequence. The median operation is performed on the deviation absolute value sequence, and the result is used as the phase difference dispersion scale. This calculation method combines circular mapping and median operation, which not only solves the problem of deviation calculation anomalies caused by phase periodicity, but also resists the interference of abnormal phase difference data, ensuring that the phase difference dispersion scale can truly reflect the fluctuation characteristics of the reliable phase difference, and provides a stable phase difference scale benchmark for the subsequent construction of cost function.

[0057] It should be noted that the predicted phase angle difference refers to the phase angle difference at future time obtained by using the phase relative drift velocity characterized by the phase difference between the two sides, based on the current reliable phase angle difference obtained by synchronous sampling on both sides of the loop switch, and by performing forward extrapolation and ring mapping on the current reliable phase angle difference over an extrapolated time span. It is used to characterize the degree of alignment that the voltage phases on both sides may reach when closing is performed at this extrapolated time span, thereby supporting the solution of the optimal closing delay.

[0058] It should be noted that the pressure difference dispersion scale refers to the scale obtained by robustly estimating the dispersion of the reliable pressure difference sequence within a set nearest window. It reflects the typical fluctuation amplitude of the reliable pressure difference under short-term operational and measurement disturbances. It is used to convert the current reliable pressure difference into a relative dimensionless deviation and reduce the impact of the difference in amplitude fluctuation dimensions under different lines, voltage levels, or sampling conditions on the cost function. The phase difference dispersion scale refers to the scale obtained by robustly estimating the circular deviation of the reliable phase difference sequence relative to its median within the same nearest window. It reflects the typical jitter level of the reliable phase difference under normal conditions and is used to convert the absolute value of the predicted phase difference into a relative dimensionless deviation. This avoids the distortion of the evaluation scale by the phase difference crossing the circular boundary or short-term spikes, thus enabling the cost function to achieve a comparable comprehensive measurement between the two different dimensional indicators, pressure difference and phase difference.

[0059] When constructing the cost function, the ratio of the current credible pressure difference to the pressure difference dispersion scale is first calculated. This ratio calculation normalizes the credible pressure difference, eliminating the influence of the magnitude difference in pressure difference on cost assessment. Then, this ratio is squared. Squaring amplifies the deviation of the credible pressure difference relative to the dispersion scale, resulting in a larger cost weight when the pressure difference deviation is large. Simultaneously, the absolute value of the predicted phase angle difference is taken to eliminate the influence of the positive or negative sign of the phase angle difference on cost calculation. The absolute value of the predicted phase angle difference is then ratiod to the phase angle difference dispersion scale to normalize the predicted phase angle difference. This ratio is also squared to amplify the influence of the phase angle difference deviation. Finally, the two squared results are added to construct the cost function. The calculation formula is as follows: ;

[0060] in The cost function value corresponding to the extrapolated time span τ, Let k be the reliable pressure difference at the current time. The pressure difference dispersion scale. This represents the predicted phase angle difference over the extrapolated time span τ corresponding to the current moment. The cost function, serving as a scale for phase angle difference dispersion, comprehensively measures the deviation between the current reliable voltage difference and the predicted phase angle difference. A smaller cost function value indicates a smaller inrush current during closing and better closing conditions. Subsequently, it iterates through all extrapolated time spans within a preset future time window. This future time window is set to one nominal power frequency cycle with a duration of twenty milliseconds. The traversal step size for the extrapolated time span is set to 0.1 milliseconds, starting from 0 milliseconds and incrementing at 0.1 millisecond intervals up to twenty milliseconds, for a total of 201 intervals. The process involves iterating through all possible time points to ensure that the entire future time window is covered and that the accuracy meets the requirements for closing control. For each traversal point, the extrapolated time span is substituted into the aforementioned cost function calculation formula to obtain the corresponding cost function value. After the traversal is completed, the minimum value among all cost function values ​​is selected, and the extrapolated time span corresponding to the minimum value is taken as the optimal closing delay. This traversal method can accurately find the moment with the minimum closing cost, ensuring the safety and stability of the closing operation, effectively avoiding damage to the equipment caused by inrush current, and adapting to the real-time requirements of the distribution network's loop-closing operation.

[0061] It should be noted that the cost function is a quantitative index used to evaluate the overall mismatch degree of loop closing under different extrapolated time spans. It is composed of the normalized deviation of the current reliable voltage difference relative to the voltage difference dispersion scale and the normalized deviation of the predicted phase angle difference relative to the phase angle difference dispersion scale. This makes the voltage amplitude inconsistency and phase inconsistency comparable in a dimensionless form, so that it can still stably reflect the circulating current impact risk level that may occur at the moment of closing, even under the background of single-phase spike cluster pollution suppression and measurement jitter. The optimal closing delay refers to the extrapolated time span that makes the cost function obtain the minimum value when traversing the extrapolated time span within the preset future time window. It corresponds to the closing time when the combined amplitude difference and phase difference of the voltage on both sides is the smallest and closest to synchronization at that moment. It is then used to control the circuit breaker to issue a closing pulse after the delay to complete the distribution network loop closing operation.

[0062] In an embodiment of the present invention, the closing feasibility is determined based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and a closing permission instruction is generated based on the closing feasibility, specifically including: The arithmetic mean of the three-phase continuous contamination weights is calculated by adding the continuous contamination weights of phases A, B, and C and dividing by the total number of phases. This average weight comprehensively reflects the degree of contamination of the three-phase sampling channels by spike clusters. A higher average weight indicates a higher overall reliability of the three-phase voltage sampling data. Then, using the natural constant as the base and the negative of the minimum cost function corresponding to the optimal closing delay as the exponent, an exponential operation is performed. This operation converts the minimum value of the cost function into a positive gain. The smaller the minimum value of the cost function, the larger the exponential result, indicating a better current closing condition. Multiplying the above average weight by the exponential result yields the closing feasibility at the current moment. The calculation formula is as follows: ;

[0063] in Let k be the feasibility of closing the circuit at the current time. For the continuous pollution weight of phase A, For the continuous pollution weight of phase B, Let e ​​be the continuous pollution weight of phase C, and let e be the natural constant. The minimum cost function corresponding to the optimal closing delay is obtained by using the arithmetic mean to fuse the three-phase continuous pollution weights, which can ensure the objective representation of the overall data credibility. The cost function value can be transformed by the exponential function to realize the nonlinear quantification of the closing quality. The closing feasibility can simultaneously reflect the credibility of the sampled data and the optimality of the closing operation. The higher the value, the more stable and reliable the closing conditions are at the current moment.

[0064] The preset number of historical sampling points is set to the number of sampling points corresponding to one nominal power frequency cycle, where the nominal power frequency cycle is 20 milliseconds and the sampling frequency is 5 kHz. This results in a preset number of 100 historical sampling points. A judgment window is constructed containing the current time and this preset number of historical sampling points. Within this judgment window, the closing feasibility values ​​corresponding to the current time and all historical sampling times are read. The closing feasibility at the current time is compared with the closing feasibility values ​​of all historical times within the window. It is determined whether the closing feasibility at the current time is the maximum value within the judgment window. This maximum value judgment method ensures that closing permission is only issued at the time with the optimal closing feasibility, avoiding multiple consecutive triggers of closing. The instruction enhances the stability and uniqueness of closing control. If the judgment result is that the closing feasibility at the current moment is the maximum value within the judgment window, then the closing permission instruction is logically true, and the closing permission instruction that allows closing is output. Based on the previously solved optimal closing delay, the timing parameter is set, and the circuit breaker is controlled to issue a closing pulse after the optimal closing delay ends, completing the loop closing operation. If the judgment result is that the closing feasibility at the current moment is not the maximum value within the judgment window, then the closing permission instruction is logically false, the loop closing state is maintained, and the closing condition judgment at the next sampling moment is waited for. This ensures that the distribution network loop closing operation is executed only at the optimal and reliable moment, effectively avoiding the risk of erroneous closing under abnormal operating conditions.

[0065] It should be noted that closing feasibility refers to a comprehensive quantity used to characterize whether the current loop closing has stable and executable conditions. It is jointly determined by the average level of the continuous contamination weight of each phase and the minimum value of the cost function corresponding to the optimal closing delay. The average level of the continuous contamination weight reflects the degree of contamination of the phase angle information of the synchronous sampling on both sides by single-phase spike clusters, while the minimum value of the cost function reflects the comprehensive mismatch between the voltage amplitude and phase on both sides at the predictable closing time. Therefore, the higher the closing feasibility, the more reliable the phase angle information, the smaller the mismatch that can be obtained, and the more suitable it is to generate closing permission. The closing pulse refers to the pulse transmitted from the control unit to the circuit breaker. The short-time control signal output by the closing actuator is used to trigger the circuit breaker to complete the mechanical closing action and change the closing point from the open state to the on state. The closing pulse is applied with a delay according to the optimal closing delay after outputting the closing permission command to match the closing window. The blocking state means that when the closing feasibility does not meet the permission generation rule or does not reach the relative optimal within the window, the control unit prohibits the closing pulse output and keeps the closing permission in a disallowed state, so that the circuit breaker does not perform the closing action in the current period, thereby avoiding the risk of closing impact when the phase angle information is contaminated or the voltage mismatch between the two sides is large.

[0066] like Figure 2 The diagram shown is a functional block diagram of a dual-sided voltage synchronous sampling switch device for distribution network loop closing operation provided by an embodiment of the present invention.

[0067] In this embodiment, the functions of each module / unit are as follows: The parameter extraction module is used to collect the three-phase voltages on both sides of the circuit breaker and perform phasor estimation to obtain the phase voltage amplitude, phase angle and frequency difference between the two sides. The baseline extraction module is used to calculate the ring phase angle difference sequence for each phase based on the phase angle, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence. The anomaly assessment module is used to calculate the significance and linkage of single-phase spike clusters based on the robust baseline, robust dispersion and voltage amplitude ratio of the ring phase angle difference sequence, and to generate the continuous pollution weight of each phase. The weighted aggregation module is used to perform weighted aggregation of robust baselines based on continuous contamination weights to obtain a reliable phase angle difference, and to aggregate the voltage amplitude ratios on both sides to obtain a reliable voltage difference. The cost calculation module is used to extrapolate the reliable phase angle difference within a preset future time window based on the frequency difference between the two sides. It constructs a cost function by combining the current reliable pressure difference with the extrapolated reliable phase angle difference and solves the optimal closing delay. The closing determination module is used to determine the closing feasibility based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and to generate a closing permission instruction based on the closing feasibility.

[0068] like Figure 3 As shown in the figure, this is a schematic diagram of the lateral displacement profile constructed based on the ventilation normal direction and its adjacent differential amplitudes. The horizontal axis is the normal coordinate, and the vertical axis is the numerical amplitude. The solid line represents the lateral displacement profile, reflecting the trend of lateral displacement along the normal coordinate direction with position change. The dashed line represents the adjacent differential amplitudes of the lateral displacement profile, used to characterize the intensity of change of the lateral displacement profile between adjacent normal positions. The center of the first strip and the center of the second strip are determined at the two significant peak positions corresponding to the adjacent differential amplitude curves, and the distance between the two strip centers is used as the strip width scale. This enables the characterization of the center position and width scale of the double strip structure in the normal coordinate, providing a basis for generating double strip membership, constructing bifurcation comparison index, and carrying out constrained processing for anomaly detection.

[0069] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for using a double-sided voltage synchronous sampling switching device for a closing operation of a power distribution network, characterized in that, include: S1. Collect the three-phase voltages on both sides of the circuit breaker and perform phasor estimation to obtain the phase voltage amplitude, phase angle and frequency difference between the two sides. S2. Calculate the ring phase angle difference sequence for each phase based on the phase angle, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence; S3. Based on the robust baseline, robust dispersion and voltage amplitude ratio of the ring phase angle difference sequence, calculate the significance and linkage of single-phase spike clusters, and generate the continuous pollution weight of each phase. S4. Based on the continuous pollution weight, the robust baseline is weighted and aggregated to obtain the reliable phase angle difference, and the voltage amplitude ratio on both sides is aggregated to obtain the reliable voltage difference. S5. Based on the frequency difference between the two sides, extrapolate the reliable phase angle difference in a preset future time window, construct a cost function by combining the current reliable voltage difference and the extrapolated reliable phase angle difference, and solve for the optimal closing delay. S6. Determine the closing feasibility based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and generate a closing permission instruction based on the closing feasibility.

2. The method of using a dual-sided voltage-synchronized sampling switch device for loop closing operation of a power distribution network according to claim 1, wherein, The three-phase voltages on both sides of the circuit breaker are collected and phasor estimation is performed to obtain the phase voltage amplitude, phase angle, and frequency difference between the two sides, including: The three-phase voltages on the first and second sides of the circuit breaker are sampled synchronously to obtain the three-phase voltage sequence on the first side and the three-phase voltage sequence on the second side. Phasor estimation is performed within the set nearest window to obtain the corresponding first-side phase voltage magnitude and first-side phase angle, as well as the second-side phase voltage magnitude and second-side phase angle. Calculate the difference between the first-side frequency and the second-side frequency, and take the median of the difference within a set nearest window to obtain the bilateral frequency difference.

3. The method of using a dual-sided voltage-synchronized sampling switch device for loop closing operation of a power distribution network according to claim 2, wherein, Based on the phase angle, calculate the ring phase angle difference sequence for each phase, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence, including: The difference between the first phase angle and the second phase angle is mapped in a ring to obtain the ring phase angle difference sequence of each phase. The ring mapping is to map the phase angle difference to the range of negative to positive pi. Within the set nearest window, the median of the ring phase difference sequence is used as the robust baseline, and the median of the absolute value of the difference between the ring phase difference and the robust baseline is calculated to obtain the robust dispersion.

4. The method of using a dual-sided voltage synchronous sampling switch device for loop closing operation in a distribution network according to claim 3, characterized in that, Based on the robust baseline, robust dispersion, and voltage amplitude ratio of the ring phase angle difference sequence, the significance and linkage of single-phase spike clusters are calculated, including: Within the set nearest window, the median of the ratio of the absolute value of the difference between the ring phase angle difference and the robust baseline to the robust dispersion is used as the significance of the single-phase peak cluster. Calculate the logarithm of the voltage amplitude ratio between corresponding phases on the first and second sides of the circuit breaker; The linkage quantity is obtained by dividing the covariance of the logarithm of the ring phase angle difference sequence and the voltage amplitude ratio within a set nearest window by the variance of the logarithm within the set nearest window.

5. The method of using a dual-sided voltage synchronous sampling switch device for loop closing operation in a distribution network according to claim 4, characterized in that, Generate the continuous contamination weights for each phase, including: The median of the significance of the single-phase peak clusters in the three phases was used as the adaptive significance scale. The median of the absolute values ​​of the three-phase linkage quantities is used as the linkage adaptive scale. For each phase, the square of the ratio of the single-phase peak cluster significance to the significance adaptive scale is used as the first penalty term; For each phase, the square of the ratio of the absolute value of the linkage quantity to the linkage adaptive scale is used as the second penalty term; For each phase, the first penalty term, the second penalty term, and 1 are summed, and the reciprocal of the sum is taken to obtain the continuous pollution weight of each phase.

6. The method of using a dual-sided voltage synchronous sampling switch device for loop closing operation in a distribution network according to claim 5, characterized in that, The reliable phase angle difference is obtained by weighting robust baselines based on continuous contamination weights, and the reliable voltage difference is obtained by aggregating the voltage amplitude ratios on both sides, including: The continuous pollution weight of each phase is used as the amplitude, and the corresponding robust baseline is used as the phase angle to construct the complex quantity of each phase. The phase angle is extracted after summing the complex quantities of the three phases to obtain the reliable phase angle difference; Calculate the absolute value of the logarithm of the three-phase voltage amplitude ratio, and take the median of this absolute value among the three phases as the reliable voltage difference.

7. The method of using a dual-sided voltage synchronous sampling switch device for loop closing operation in a distribution network according to claim 6, characterized in that, Based on the frequency difference between the two sides, the reliable phase angle difference is extrapolated into the pre-defined future time window. A cost function is constructed by combining the current reliable voltage difference with the extrapolated reliable phase angle difference. The optimal closing delay is then solved, including: Within a preset future time window, calculate the product of twice the value of pi, the frequency difference between the two sides, and the extrapolated time span. Add the product to the current reliable phase angle difference to obtain the predicted phase angle difference, and map the predicted phase angle difference to the range of negative to positive pi. Within the nearest window, a reliable pressure difference sequence is calculated for each sampling time. The absolute value of the difference between the reliable pressure difference sequence and its median is calculated, and the median of the absolute value of the difference within the nearest window is taken as the pressure difference dispersion scale. Within the nearest window, a reliable phase difference sequence is calculated for each sampling time. The difference between the reliable phase difference sequence and its median is calculated. The absolute value of the difference is then obtained by performing a circular mapping. The median of the obtained absolute value within the nearest window is used as the phase difference dispersion scale. The cost function is constructed by adding the square of the ratio of the current reliable pressure difference to the pressure difference dispersion scale, and the square of the ratio of the absolute value of the predicted phase angle difference to the phase angle difference dispersion scale. The extrapolated time span within the preset future time window is traversed, and the extrapolated time span that minimizes the cost function is taken as the optimal closing delay.

8. The method of using a dual-sided voltage synchronous sampling switch device for loop closing operation in a distribution network according to claim 7, characterized in that, The feasibility of closing is determined based on the minimum cost function corresponding to the optimal closing delay and the continuous contamination weight, and a closing permission instruction is generated based on the closing feasibility, including: Calculate the average value of the continuous pollution weights of the three phases, and multiply this average value by a power of the natural constant with the negative of the minimum cost function as the exponent to obtain the current closing feasibility. Within a window containing the current time and the preset number of historical sampling points, determine whether the closing feasibility at the current time is at its maximum value; if so, output a closing permission command that allows closing and control the circuit breaker to issue a closing pulse after the optimal closing delay; if not, maintain the blocked state.

9. A dual-sided voltage synchronous sampling switch device for distribution network loop closing operation, applied in the method of using the dual-sided voltage synchronous sampling switch device for distribution network loop closing operation as described in any one of claims 1-8, characterized in that, The device includes: The parameter extraction module is used to collect the three-phase voltages on both sides of the circuit breaker and perform phasor estimation to obtain the phase voltage amplitude, phase angle and frequency difference between the two sides. The baseline extraction module is used to calculate the ring phase angle difference sequence for each phase based on the phase angle, and extract the robust baseline and robust dispersion of the ring phase angle difference sequence. The anomaly assessment module is used to calculate the significance and linkage of single-phase spike clusters based on the robust baseline, robust dispersion and voltage amplitude ratio of the ring phase angle difference sequence, and to generate the continuous pollution weight of each phase. The weighted aggregation module is used to perform weighted aggregation of robust baselines based on continuous contamination weights to obtain a reliable phase angle difference, and to aggregate the voltage amplitude ratios on both sides to obtain a reliable voltage difference. The cost calculation module is used to extrapolate the reliable phase angle difference between the two sides within a preset future time window based on the frequency difference between the two sides. It constructs a cost function by combining the current reliable pressure difference with the extrapolated reliable phase angle difference and solves the optimal closing delay. The closing determination module is used to determine the closing feasibility based on the minimum cost function corresponding to the optimal closing delay and the continuous pollution weight, and to generate a closing permission instruction based on the closing feasibility.

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