Dual-inlet mutual backup intelligent boundary switch and control method thereof

Abstract

The application discloses a double incoming line mutual backup type intelligent boundary switch and a control method thereof. The intelligent boundary switch comprises a first incoming line interface, a second incoming line interface, an outgoing line interface, a first switch executing mechanism, a second switch executing mechanism, a power parameter acquisition module, a man-machine interactive terminal and an intelligent controller. The intelligent controller dynamically calculates a power quality comprehensive evaluation index according to real-time acquisition of double-path power supply voltage, current, frequency and phase, controls the switch executing mechanism to close or open based on comparison of the index and a dynamic threshold value, realizes double incoming line mutual backup switching, calculates a zero sequence active power direction angle according to zero sequence voltage and zero sequence current at the outgoing line interface, and judges that it is a user side grounding fault and outputs a backup power automatic switching blocking signal when the direction angle falls into a user side fault direction angle interval. The application does not need a superior instruction, independently completes power quality deterioration identification, optimized switching and user side fault blocking at the end of a distribution network, and improves power supply reliability.

Description

Technical Field

[0001] This invention relates to the field of power distribution network automation technology, specifically to a dual-incoming-line mutual backup intelligent sectionalizing switch and its control method. Background Technology

[0002] In power distribution networks, sectionalizing switches are critical electrical devices installed at the connection points between the main and branch lines. They are used to isolate faulty areas when a branch line fails, ensuring normal power supply to the main line and other branch lines. Traditional sectionalizing switches typically have a single incoming and single outgoing line structure, allowing only one power supply line to be connected. When this single power supply is interrupted due to fault, maintenance, or other reasons, all loads downstream of the sectionalizing switch will be forced to shut down until power is restored or a manual switching operation is performed. This limitation is particularly pronounced in critical load locations such as industrial parks, data centers, and hospitals, where a single power failure can lead to production line shutdowns, data loss, or medical equipment outages, causing severe economic losses and social impact.

[0003] To address these issues, some existing solutions employ independent backup lines in conjunction with diesel generators as backup power. However, this approach incurs high investment and maintenance costs, and the start-up and grid connection of diesel generators require considerable time, making it difficult to achieve continuous power supply to the load. Other solutions utilize conventional automatic transfer switches (ATS), but these rely on instructions from upstream substations or complex switchgear configurations, hindering rapid and independent localized switching at the distribution network end. Furthermore, existing dual-power switching solutions generally lack comprehensive assessment capabilities of the power quality of both power sources. Switching decisions are often based solely on the presence or absence of voltage or a comparison of a single characteristic with a preset static threshold. This fails to proactively optimize switching when power quality gradually deteriorates but before complete power loss, potentially leading to prolonged operation of the load under substandard power conditions, impacting equipment lifespan and production quality. Meanwhile, conventional automatic transfer switch (ATS) devices lack the ability to detect faults on the user side. When a permanent ground fault occurs on the user side, after the sectionalizing switch trips and isolates the fault, the ATS device may mistakenly activate due to detecting a loss of voltage on the main incoming line, transferring the backup power supply to the faulty branch. This causes the backup power supply to also trip due to the fault, expanding the power outage area and damaging equipment. Therefore, there is an urgent need for a sectionalizing switch solution that can independently complete the early detection and optimized switching of gradual power quality degradation of dual power sources at the end of the distribution network, while also possessing user-side fault directionality detection and reliable ATS interlocking functions. Summary of the Invention

[0004] This invention provides a dual-incoming-line mutual backup intelligent sectionalizing switch and its control method, aiming to solve the technical problems that existing sectionalizing switches cannot independently achieve early detection and optimized switching of gradual power quality degradation at the end of the distribution network, and cannot reliably block automatic transfer backup when there is a fault on the user side.

[0005] To achieve the above objectives, this invention provides a dual-input, mutually redundant intelligent boundary switch, comprising a first input interface, a second input interface, an output interface, a first switch actuator, a second switch actuator, a power parameter acquisition module, a human-machine interface display terminal, and an intelligent controller. The first input interface is used to connect to a first power line, the second input interface is used to connect to a second power line, and the output interface is used to connect to a load line. The first switch actuator is connected between the first input interface and the output interface to control the on / off state of the electrical connection between them; the second switch actuator is connected between the second input interface and the output interface to control the on / off state of the electrical connection between them. The power parameter acquisition module is electrically connected to both the first and second input interfaces to acquire the voltage, current, frequency, and phase of the first and second power lines in real time. The human-machine interface display terminal displays the operating parameters of the first and second power lines, as well as the switching status of the first and second switch actuators. The intelligent controller is electrically connected to the power parameter acquisition module, the first switch actuator, the second switch actuator, and the human-machine interface display terminal. It is used to dynamically calculate the comprehensive power quality evaluation index based on voltage, current, frequency, and phase. Based on the comparison result of the index and the dynamic threshold, it controls the two switch actuators to perform closing or opening operations to realize the mutual backup switching of the dual incoming lines. It is also used to calculate the zero-sequence active power direction angle based on the zero-sequence voltage and zero-sequence current at the outgoing line interface. When the direction angle enters the preset user-side fault direction angle interval, it controls the currently closed switch actuator to open and outputs the backup automatic transfer interlocking signal.

[0006] In the above technical solution, the intelligent controller includes a data acquisition and processing unit, a power quality assessment unit, a switching decision unit, a synchronization detection unit, and a drive control unit. The data acquisition and processing unit is electrically connected to the power parameter acquisition module and is used to receive and analyze the voltage, current, frequency, and phase data uploaded by the power parameter acquisition module, and to perform moving average filtering and true RMS calculation on the received signals. The power quality assessment unit is electrically connected to the data acquisition and processing unit and is used to calculate the comprehensive power quality assessment index for the first and second power supply lines based on the filtered and calculated voltage, current, frequency, and phase data. The switching decision unit is electrically connected to the power quality assessment unit and is used to generate a switching command according to a preset switching control strategy based on the comparison result of the comprehensive power quality assessment index and a dynamic threshold. The synchronization detection unit is electrically connected to the switching decision unit and is used to compare the voltage difference, frequency difference, and phase difference between the first and second power supply lines before executing the closing operation, and only allows the closing command output by the switching decision unit to take effect when the voltage difference, frequency difference, and phase difference all meet the preset synchronization closing conditions. The drive control unit is electrically connected to the switching decision unit, the first switch actuator, and the second switch actuator, respectively, and is used to drive the first switch actuator or the second switch actuator to perform closing or opening operations according to the switching command.

[0007] By setting up a data acquisition and processing unit to filter and calculate the true RMS value of power parameters, sampling noise and harmonic interference can be effectively eliminated, improving measurement accuracy. The power quality assessment unit incorporates multi-dimensional parameters into a unified assessment framework, which can comprehensively reflect the actual power quality status of the power supply line and overcome the limitations of traditional solutions that rely solely on a single voltage parameter or a single feature compared with a preset static threshold. The synchronization detection unit performs strict synchronization condition verification before closing, effectively preventing the impact of asynchronous closing on equipment and the power grid. The collaborative work of each functional unit realizes a complete closed loop from data acquisition to execution control.

[0008] In the above technical solution, the intelligent controller also includes a lockout protection unit. The lockout protection unit is electrically connected to the drive control unit and, upon detecting a short-circuit fault in the first or second power line, outputs a lockout signal to the drive control unit within a preset lockout action time, prohibiting the corresponding line's switch actuator from performing a closing operation. By setting an independent lockout protection unit, the closing circuit can be quickly locked out when a short-circuit fault occurs, preventing the fault from escalating and ensuring equipment and line safety.

[0009] In the above technical solution, the comprehensive power quality assessment index is dynamically calculated according to the following formula:

[0010]

[0011] in, express The comprehensive power quality assessment index at any given time; express The real-time effective value of the voltage at any given moment; Indicates the rated voltage value; express The real-time RMS value of the current at any given moment; Indicates the rated current value; express Real-time frequency value at any given moment; Indicates the rated frequency value; express Real-time phase angle at any given moment; , , , These are the voltage weighting coefficient, current weighting coefficient, frequency weighting coefficient, and phase weighting coefficient, respectively. This comprehensive power quality assessment index incorporates parameters from four dimensions—voltage, current, frequency, and phase—into a unified evaluation framework. It comprehensively reflects the actual power quality of power lines, overcoming the limitations of traditional solutions that rely solely on a single voltage parameter. The weighting coefficients can be flexibly configured according to the actual needs of different application scenarios, enabling the system to adapt to the varying power quality requirements of different load types.

[0012] In the above technical solution, the dynamic threshold is updated dynamically in the following manner:

[0013]

[0014] in, express The dynamic threshold at any given time; This indicates the preset baseline threshold. This represents the adaptive adjustment coefficient; Indicates the length of the sliding window; express The comprehensive power quality assessment index at any given time; This represents the average value of the comprehensive power quality assessment index within the sliding window. Through a dynamic threshold update mechanism, the threshold can adaptively adjust to follow historical fluctuations in power line power quality, avoiding potential misjudgments or omissions that might occur with fixed thresholds when power quality fluctuates significantly, thus improving the accuracy and robustness of switching decisions.

[0015] In the above technical solution, the benchmark threshold The adaptive adjustment coefficient is calculated by taking the 5th percentile of the comprehensive power quality assessment index during the historical normal operation period of the line. The range of values ​​is to Sliding window length The range of values ​​is to One sampling period.

[0016] In the above technical solution, the conditions for simultaneous closing are:

[0017]

[0018]

[0019]

[0020] in, and These represent the real-time effective voltage values ​​of the first and second power supply lines, respectively. and These represent the real-time frequency values ​​of the first and second power supply lines, respectively. and These represent the real-time phase angles of the first and second power supply lines, respectively. This indicates the preset voltage deviation allowable coefficient; This indicates the preset allowable frequency deviation coefficient; This indicates the preset allowable phase deviation value. By setting multi-dimensional synchronization closing conditions, simultaneous verification is performed on three dimensions: voltage difference, frequency difference, and phase difference. This ensures that the electrical parameters of the two power supplies are highly consistent at the time of closing, minimizing the closing inrush current and guaranteeing the safe and stable operation of equipment and the power grid.

[0021] In the above technical solution, the intelligent controller calculates the zero-sequence active power direction angle according to the following formula:

[0022]

[0023] in, Indicates the direction angle of zero-sequence active power; express The instantaneous value of the zero-sequence voltage at time t; express The instantaneous value of the zero-sequence current at time t; express Hilbert transform; Indicates the power frequency period; The unit represents the imaginary number. The zero-sequence voltage and zero-sequence current are acquired by a zero-sequence voltage sensor and a zero-sequence current transformer located at the outgoing interface. The preset user-side fault direction angle range is... In a 10 kV distribution network with an ungrounded neutral point or grounded via an arc suppression coil, when a single-phase ground fault occurs downstream of the outgoing interface (i.e., on the user side), the zero-sequence current lags behind the zero-sequence voltage by approximately [missing information]. to (Right now When a single-phase ground fault occurs upstream of the outgoing interface, i.e., on the system side, the direction of the zero-sequence current is opposite to that described above. This direction angle discrimination method can accurately distinguish between user-side faults and system-side faults. When the effective value of the zero-sequence current is greater than the zero-sequence action threshold and the zero-sequence active power direction angle... Falling into the preset user-side fault direction angle range When the fault is determined to be a grounding fault on the downstream user side of the outgoing interface, the switch actuator currently in the closed state is controlled to open and output a backup automatic transfer interlocking signal.

[0024] In the above technical solution, the zero-sequence action threshold value is based on Adjustment, among which The reliability coefficient is set to a value of [value missing]. to , This is the effective value of the zero-sequence current corresponding to the maximum capacitive current when the system is operating normally.

[0025] In the above technical solution, the preset switching control strategy is as follows: when the comprehensive power quality assessment index of the first power line is greater than or equal to the dynamic threshold, the first switch actuator is controlled to be in the closed state and the second switch actuator is controlled to be in the open state; when the comprehensive power quality assessment index of the first power line is less than the dynamic threshold and the comprehensive power quality assessment index of the second power line is greater than or equal to the dynamic threshold, the first switch actuator is controlled to perform an open operation and the second switch actuator to perform a closed operation; when the comprehensive power quality assessment indices of both the first and second power lines are less than the dynamic threshold, both the first and second switch actuators are controlled to be in the open state. This switching control strategy realizes the complete logic of power quality-driven intelligent switching, main supply priority, and dual-path fault protection.

[0026] In the above technical solution, the outer casing of the dual-input backup switch body is provided with a first energy harvesting compartment and a second energy harvesting compartment. The first energy harvesting compartment contains a first voltage energy harvesting unit connected in parallel between the first input terminal and the ground wire, and the second energy harvesting compartment contains a second voltage energy harvesting unit connected in parallel between the second input terminal and the ground wire. A sealed controller cavity is fixedly connected to the lower part of the outer casing. The intelligent controller is encapsulated within the sealed controller cavity, which is filled with thermally conductive silicone and has a desiccant pack attached to its inner wall. By setting up independent energy harvesting compartments and a sealed controller cavity, physical isolation between high-voltage and low-voltage control is achieved. The thermally conductive silicone and desiccant pack ensure the long-term stable operation of the intelligent controller in outdoor high-temperature, high-humidity environments.

[0027] In the above technical solution, the dual-incoming-line backup switch body is provided with a first vacuum interrupter, a second vacuum interrupter, and a mechanical interlocking linkage. The mechanical interlocking linkage includes a first crank arm, a second crank arm, a linkage slide rod, and a limit stop. The first crank arm is fixed to the operating spindle of the first vacuum interrupter, and the second crank arm is fixed to the operating spindle of the second vacuum interrupter. The linkage slide rod has a first limit groove and a second limit groove along its axial direction. When the first vacuum interrupter is in the closed position, the first crank arm is inserted into the first limit groove, and the second crank arm is blocked by the limit stop, keeping the second vacuum interrupter open. When the second vacuum interrupter is in the closed position, the second crank arm is inserted into the second limit groove, and the first crank arm is blocked by the limit stop, keeping the first vacuum interrupter open. This mechanical interlocking linkage physically ensures that the first and second vacuum interrupters are not in the closed position at the same time, effectively preventing the parallel operation of two power supplies.

[0028] This invention also provides a control method for a dual-input line mutual backup intelligent sectionalizing switch, comprising the following steps: real-time acquisition of voltage, current, frequency, and phase of the first and second power lines via a power parameter acquisition module; performing moving average filtering and true RMS calculation on the acquired voltage, current, frequency, and phase; calculating the comprehensive power quality evaluation index of the first and second power lines based on the filtered and calculated voltage, current, frequency, and phase; generating a switching command based on a comparison between the comprehensive power quality evaluation index and a dynamic threshold according to a preset switching control strategy; comparing the voltage difference, frequency difference, and phase difference between the first and second power lines before performing the closing operation, and allowing the switching command to take effect only when the voltage difference, frequency difference, and phase difference all meet the preset synchronous closing conditions; and driving the first or second switch actuator to perform the closing or opening operation according to the switching command. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the system architecture of the dual-input mutual backup intelligent boundary switch of the present invention.

[0030] Figure 2 This is a schematic diagram of the control method for the dual-input, mutually redundant intelligent boundary switch of the present invention. Detailed Implementation

[0031] 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 a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1 As shown, the present invention provides a dual-input backup intelligent boundary switch, including a first input interface, a second input interface, an output interface, a first switch actuator, a second switch actuator, a power parameter acquisition module, a human-machine interaction display terminal, and an intelligent controller.

[0034] The first incoming interface is used to connect to the first power supply line, and the second incoming interface is used to connect to the second power supply line. In this embodiment, the first power supply line is the main power supply line, and the second power supply line is the backup power supply line; both power supply lines are drawn from the 10kV distribution network. The outgoing interface is used to connect to the load line to supply power to downstream user equipment. In this invention, the outgoing interface is simply the same as the first switch actuator and the second switch actuator are both connected to this outgoing interface. The first incoming interface, the second incoming interface, and the outgoing interface all use power terminals that conform to national standards, possessing reliable electrical connection performance and sufficient current carrying capacity.

[0035] The first switch actuator is connected between the first incoming and outgoing interfaces, and is used to control the on / off state of the electrical connection between the first incoming and outgoing interfaces. The second switch actuator is connected between the second incoming and outgoing interfaces, and is used to control the on / off state of the electrical connection between the second incoming and outgoing interfaces. Both the first and second switch actuators are vacuum circuit breakers or load switches, possessing rapid opening and closing capabilities and reliable arc-extinguishing performance.

[0036] The power parameter acquisition module is electrically connected to the first and second incoming interfaces, respectively, and is used to acquire the voltage, current, frequency, and phase of the first and second power lines in real time. The power parameter acquisition module achieves electrical isolation from the high-voltage lines through voltage and current transformers to ensure sampling safety.

[0037] The human-machine interface display terminal is used to display the operating parameters of the first and second power supply lines, as well as the switching status of the first and second switch actuators. In this embodiment, the human-machine interface display terminal uses a 5-inch serial port screen, which can display the voltage, current, frequency, phase, and other parameters of the two power supplies, as well as the on / off status of the switches, in real time in both digital and graphical formats, facilitating on-site monitoring and operation by operators.

[0038] The intelligent controller is electrically connected to the power parameter acquisition module, the first switch actuator, the second switch actuator, and the human-machine interface display terminal. The intelligent controller dynamically calculates the comprehensive power quality assessment index of the first and second power lines based on the voltage, current, frequency, and phase data collected in real time by the power parameter acquisition module. Based on the comparison between the comprehensive power quality assessment index and a dynamic threshold, the intelligent controller controls the first and second switch actuators to perform closing or opening operations. Simultaneously, the intelligent controller also calculates the zero-sequence active power direction angle based on the zero-sequence voltage obtained from the zero-sequence voltage sensor located at the outgoing line interface and the zero-sequence current obtained from the zero-sequence current transformer located at the outgoing line interface. When this direction angle falls within a preset user-side fault direction angle interval... When the switch is closed, the controller opens the circuit breaker and outputs a backup automatic transfer interlock signal. The intelligent controller uses a high-performance embedded microcontroller with powerful computing capabilities and rich peripheral interfaces, which can meet the needs of real-time acquisition of dual-channel power parameters and rapid control decision-making.

[0039] In this embodiment, the intelligent controller implements dual-input line backup switching and fault interlocking in the following manner: Under normal operating conditions, when the comprehensive power quality assessment index of the first power line is greater than or equal to the dynamic threshold, the intelligent controller controls the first switch actuator to be in the closed state and the second switch actuator to be in the open state, with the load powered by the first power line. When the intelligent controller detects that the comprehensive power quality assessment index of the first power line drops below the dynamic threshold, it immediately determines the comprehensive power quality assessment index of the second power line; if the comprehensive power quality assessment index of the second power line is greater than or equal to the dynamic threshold, the intelligent controller controls the first switch actuator to perform an open operation, and then controls the second switch actuator to perform a close operation, switching the load to the second power line. The entire switching process is completed within milliseconds, and the load side hardly feels any power interruption. When the intelligent controller detects a ground fault on the downstream user side of the outgoing interface through the zero-sequence voltage sensor and the zero-sequence current transformer, it immediately controls the currently closed switch actuator to open to isolate the fault and outputs a backup automatic transfer interlocking signal to prevent the backup power supply from being mistakenly connected to the faulty branch.

[0040] Example 2

[0041] This embodiment provides a detailed description of the internal structure of the intelligent controller. The intelligent controller includes a data acquisition and processing unit, a power quality assessment unit, a switching decision unit, a synchronization detection unit, and a drive control unit.

[0042] The data acquisition and processing unit is electrically connected to the power parameter acquisition module. It receives and analyzes the voltage, current, frequency, and phase data uploaded by the power parameter acquisition module, and performs moving average filtering and true RMS calculation on the received signals. The moving average filtering algorithm is executed according to the following formula:

[0043]

[0044] in, The filter window length is 8 in this embodiment; For the first The original value of the second sample; For the first The output value after sampling and filtering. Moving average filtering effectively eliminates random noise and transient interference introduced during sampling, improving the stability of the measurement data. The true RMS value is calculated using the following formula:

[0045]

[0046]

[0047] in, and These are the effective values ​​of voltage and current, respectively. and The first Instantaneous voltage and current values ​​at each sampling point; This represents the number of sampling points within one period. The true RMS algorithm accurately reflects the true RMS value of non-sinusoidal and harmonic waveforms, ensuring measurement accuracy.

[0048] The power quality assessment unit is electrically connected to the data acquisition and processing unit. It is used to calculate the comprehensive power quality assessment index of the first power line and the second power line based on the voltage, current, frequency and phase after filtering and true RMS calculation.

[0049] The switching decision unit is electrically connected to the power quality assessment unit and is used to generate switching commands according to a preset switching control strategy based on the comparison results of the comprehensive power quality assessment index and the dynamic threshold.

[0050] The synchronization detection unit is electrically connected to the switching decision unit. Before performing the closing operation, it compares the voltage difference, frequency difference, and phase difference between the first power line and the second power line. The closing command output by the switching decision unit is allowed to take effect only when the voltage difference, frequency difference, and phase difference all meet the preset synchronization closing conditions.

[0051] The drive control unit is electrically connected to the switching decision unit, the first switch actuator, and the second switch actuator, respectively, and is used to drive the first switch actuator or the second switch actuator to perform closing or opening operations according to the switching command. The drive control unit outputs an electrical signal with sufficient driving capability to reliably drive the electromagnetic closing and opening coils.

[0052] Example 3

[0053] In this embodiment, the intelligent controller also includes a lockout protection unit. The lockout protection unit is electrically connected to the drive control unit and, upon detecting a short-circuit fault in the first or second power line, outputs a lockout signal to the drive control unit within a preset lockout action time, prohibiting the corresponding line's switch actuator from performing a closing operation. The lockout protection unit operates independently of the switching decision unit and can lock the closing circuit at the fastest speed when a short-circuit fault occurs, preventing the circuit breaker from closing under fault conditions, which could lead to equipment damage or fault escalation.

[0054] Example 4

[0055] This embodiment provides a detailed explanation of the calculation of the comprehensive power quality assessment index and dynamic threshold.

[0056] The comprehensive power quality assessment index is dynamically calculated according to the following formula:

[0057]

[0058] in, express The power quality comprehensive assessment index at time t, its value range is A higher value indicates better power quality. express The real-time effective value of the voltage at any given time, in volts; This indicates the rated voltage value. For a 10kV distribution network, V; express The real-time RMS current value at any given time, in amperes; This indicates the rated current value, in amperes. express The real-time frequency value at any given moment, in Hertz; Indicates the rated frequency value. Hz; express The real-time phase angle at any given moment, in degrees; , , , These are the voltage weighting coefficient, current weighting coefficient, frequency weighting coefficient, and phase weighting coefficient, respectively. .

[0059] In this embodiment, for an industrial park scenario dominated by linear loads, the weighting coefficients are set as follows: , , , This means that voltage stability has the highest weight. For data center scenarios with predominantly nonlinear loads, the weighting coefficients can be adjusted as follows: , , , This means that the phase stability weight is increased. The specific value of the weighting coefficient can be flexibly configured according to the actual application scenario and load characteristics, so that the system can adapt to the different requirements of different users for various dimensions of power quality.

[0060] The dynamic threshold is updated dynamically in the following way:

[0061]

[0062] in, express The dynamic threshold at any given time; This represents a preset baseline threshold, in this embodiment... Take the 5th percentile of the comprehensive power quality assessment index during the historical normal operation period of the line; This represents the adaptive adjustment coefficient, in this embodiment... ; In this embodiment, the sliding window length is indicated. ; express The comprehensive power quality assessment index at any given time; The average value of the comprehensive power quality assessment index within the sliding window is calculated using the following formula:

[0063]

[0064] Dynamic threshold The physical meaning is: at the baseline threshold Based on this, a correction factor proportional to the historical variance of the comprehensive power quality assessment index is added. When the power quality of the power line fluctuates significantly, the dynamic threshold is increased accordingly to avoid frequent false switching due to normal fluctuations; when the power quality of the power line is stable, the dynamic threshold returns to the baseline value to maintain a sensitive response to actual degradation. This dynamic threshold mechanism enables the switching decision to have both reliable detection capability for continuous power quality degradation and anti-interference capability for instantaneous fluctuations.

[0065] Example 5

[0066] This embodiment provides a detailed explanation of the parameter range for the dynamic threshold.

[0067] benchmark threshold The 5th percentile of the comprehensive power quality assessment index during the historical normal operation period of the line is used. This method is based on the fact that the 5th percentile represents the lower boundary of the historical normal operation state; power quality below this value can be considered abnormal or deteriorated. Adaptive adjustment coefficient. The range of values ​​is to .when When the value is small (close to) Dynamic thresholds are less responsive to historical fluctuations and are suitable for lines with relatively stable power quality; when When the value is large (close to) The dynamic threshold is more sensitive to historical fluctuations and is suitable for lines with large power quality fluctuations. Sliding window length. The range of values ​​is to Each sampling period. When When the value is small (close to) The dynamic threshold responds quickly to recent fluctuations, but may be affected by short-term disturbances; when When the value is large (close to) Dynamic thresholds reflect long-term trends more accurately, but their response speed is slower. Specific values ​​can be adjusted based on the actual operating characteristics of the line.

[0068] Example 6

[0069] This embodiment provides a detailed description of the conditions for synchronous closing.

[0070] The conditions for synchronous closing are:

[0071]

[0072]

[0073]

[0074] in, and These represent the real-time effective voltage values ​​of the first and second power supply lines, respectively, in volts. and These represent the real-time frequency values ​​of the first and second power supply lines, respectively, in Hertz. and These represent the real-time phase angles of the first and second power supply lines, respectively, in degrees. This represents the preset voltage deviation tolerance coefficient, in this embodiment... That is, the allowable voltage deviation shall not exceed 5% of the rated voltage; This represents the preset frequency deviation allowable coefficient, in this embodiment That is, the allowed frequency deviation shall not exceed 1% of the rated frequency; This represents the preset allowable phase deviation value, in this embodiment... That is, the phase deviation is allowed to be no more than 5 degrees.

[0075] Before each closing operation, the synchronization detection unit compares the voltage, frequency, and phase of the two power supplies according to the three conditions mentioned above. Only when all three conditions are met simultaneously will the synchronization detection unit allow the closing command output by the switching decision unit to take effect; otherwise, the closing command is suspended until the synchronization conditions are met or a timeout occurs. This strict synchronization detection mechanism effectively prevents inrush currents and mechanical stresses caused by asynchronous closing to power equipment and the power grid system, ensuring the safety of the switching operation.

[0076] In this embodiment, the synchronization detection unit is also equipped with a timeout protection function: if the synchronization condition cannot be met within the preset timeout period (e.g., 500 milliseconds), the synchronization detection unit will automatically cancel the current closing command and send an alarm message to the human-machine interaction display terminal, prompting the operator to manually check the phase relationship between the two power supplies.

[0077] Example 7

[0078] This embodiment provides a detailed explanation of the calculation of the zero-sequence active power direction angle and the fault direction determination.

[0079] The intelligent controller calculates the zero-sequence active power direction angle according to the following formula:

[0080]

[0081] in, Indicates the direction angle of zero-sequence active power; express The instantaneous value of the zero-sequence voltage at time t; express The instantaneous value of the zero-sequence current at time t; express Hilbert transform; Indicates the power frequency period, Second; The unit represents the imaginary number. The zero-sequence voltage and zero-sequence current are obtained by a zero-sequence voltage sensor and a zero-sequence current transformer located at the outgoing interface.

[0082] The physical meaning of the above formula is: by calculating the real and virtual work integrals of the zero-sequence voltage and zero-sequence current over one power frequency cycle, the direction angle of the zero-sequence active power can be obtained. . The sign and magnitude of the zero-sequence power reflect the direction of the zero-sequence power flow.

[0083] The preset user-side fault direction angle range is In a 10 kV distribution network with an ungrounded neutral point or grounded via an arc suppression coil, when a single-phase ground fault occurs downstream of the outgoing interface (i.e., on the user side), the zero-sequence current at the fault point flows from the system capacitance into the fault point. The zero-sequence current measured at the sectionalizing switch lags the zero-sequence voltage by approximately [missing information]. to ,Right now When a single-phase ground fault occurs upstream of the outgoing interface, i.e., on the system side, the direction of the zero-sequence current is opposite to that described above. .

[0084] Zero-order action threshold value Adjustment, among which For the reliability coefficient, take... to , This is the effective value of the zero-sequence current corresponding to the maximum capacitive current when the system is operating normally.

[0085] The direction determination process of the intelligent controller is as follows: continuously monitor the effective value of the zero-sequence current. ,like Then return to wait; if Then calculate the zero-sequence active power direction angle. ;like Then it is determined to be a grounding fault on the downstream user side of the outgoing interface; if If the fault is determined to be a ground fault on the system side or bus side, an alarm signal will be sent but the circuit breaker will not trip or block the automatic transfer switch.

[0086] When a ground fault is detected on the user side, the intelligent controller immediately outputs a trip command to trip the switch actuator that is currently in the closed state. At the same time, it sets the backup automatic transfer interlocking flag in the internal register and outputs the backup automatic transfer interlocking signal to prevent the backup power supply from being mistakenly connected to the faulty branch.

[0087] Example 8

[0088] This embodiment provides a detailed description of the preset switching control strategy.

[0089] The preset switching control strategy is implemented in the form of a finite state machine, including the following five states:

[0090] State 0: Initialization State. Upon power-up, the system first enters the initialization state. In this state, the intelligent controller performs system self-tests, peripheral initialization, parameter loading, and other operations. After initialization, the system automatically transitions to the corresponding operating state based on the actual status of the two power supplies.

[0091] Status 1: Main power supply operation status. When the comprehensive power quality assessment index of the first power supply line... Greater than or equal to the dynamic threshold If no backup automatic transfer interlock signal is received, the system enters the main power supply operation state. In this state, the intelligent controller controls the first switch actuator to be in the closed state and the second switch actuator to be in the open state, and the load is powered by the first power supply line. The human-machine interface display terminal displays the "Main Power Supply Operation" indicator.

[0092] State 2: Switching process state. When the system detects a switchover from the main power supply operation state to the first power supply line... And the second power supply line If no backup automatic transfer interlock signal is received, the system enters the switching process state. In this state, the intelligent controller first controls the first switch actuator to perform a tripping operation. After confirming that the first switch actuator is fully tripped, it then controls the second switch actuator to perform a closing operation. The switching process state is a transitional state. After the switching is completed, the system automatically switches to auxiliary power supply operation state.

[0093] State 3: Auxiliary Power Supply Operation. When the second switch actuator successfully closes and the first switch actuator is in the open state, the system enters auxiliary power supply operation state. In this state, the load is powered by the second power supply line. The human-machine interface display terminal shows the "Auxiliary Power Supply Operation" indicator. When the intelligent controller detects that the first power supply line has been restored and... When necessary, the system can automatically switch back to the main power supply operation state or maintain the auxiliary power supply operation state until manual intervention is required, depending on the configuration.

[0094] State 4: Fault Protection State. When the first power line and the second power line... and When the intelligent controller outputs a backup automatic transfer interlock signal, the system enters a fault protection state. In this state, the intelligent controller controls both the first and second switch actuators to be in the open state (or remain open), cutting off all outputs and protecting the load equipment from damage caused by abnormal power supply. The human-machine interface display terminal displays "Dual-path fault" or "User-side fault interlock" alarm information.

[0095] The core logic of the above switching control strategy can be summarized into three rules:

[0096] Rule 1: When the power quality of the first power supply line is good ( When there is no backup automatic transfer interlock signal, the first power supply line shall be used to control the first switch actuator to close and the second switch actuator to open.

[0097] Rule 2: When the power quality of the first power supply line deteriorates ( And the power quality of the second power supply line is good. When there is no backup automatic transfer interlock signal, the switch from the first power line to the second power line is automatically executed, controlling the first switch actuator to open and the second switch actuator to close.

[0098] Rule 3: When the power quality of both power sources deteriorates ( When a backup automatic transfer interlock signal is received, all outputs are cut off or closing is prohibited.

[0099] Example 9

[0100] This embodiment provides a detailed description of the housing structure and internal mechanical structure of the dual-input backup switch body.

[0101] The outer casing of the dual-input line backup switch body is provided with a first energy extraction compartment and a second energy extraction compartment. The first energy extraction compartment contains a first voltage energy extraction unit connected in parallel between the first input terminal and the ground wire, and the second energy extraction compartment contains a second voltage energy extraction unit connected in parallel between the second input terminal and the ground wire. The first and second energy extraction compartments are respectively voltage transformer mounting cavities cast on both sides of the upper end of the dual-input line backup switch body. The cavity openings are secured with silicone rubber sealing rings and cover plates bolted together. Primary terminals are led outwards to connect to the leads of the first or second input terminal.

[0102] A sealed controller cavity is fixed to the lower part of the outer casing, and the intelligent controller is encapsulated within the sealed controller cavity. The sealed controller cavity is a die-cast aluminum alloy part with an anti-corrosion spray coating. It is fixed to the lower flange of the dual-input backup switch body by stainless steel clamps, and a fluororubber O-ring seal is installed between the cavity and the cover plate. The sealed controller cavity is filled with thermally conductive silicone to achieve thermal coupling between the intelligent controller printed circuit board assembly and the inner wall of the cavity, facilitating natural convection heat dissipation. A molecular sieve desiccant pack is placed at the top of the cavity to maintain a dry atmosphere. All secondary leads passing through the wall of the sealed controller cavity are introduced through aviation plugs and epoxy resin potted lead tubes to prevent condensation and water ingress.

[0103] The low-voltage AC power output from the secondary sides of the first and second voltage power harvesting units is rectified and regulated to power the intelligent controller and operating mechanism, and provides a reference for the zero-sequence voltage sensor. When the first voltage power harvesting unit loses power, the second voltage power harvesting unit automatically takes over the control power supply, ensuring that the automatic transfer switch control circuit still has working power in the event of a voltage loss.

[0104] The dual-incoming-line backup switch body contains a first vacuum interrupter, a second vacuum interrupter, and a mechanical interlocking linkage. The mechanical interlocking linkage includes a first crank arm, a second crank arm, a linkage slide rod, and a limit stop. The first crank arm is fixed to the operating spindle of the first vacuum interrupter, and the second crank arm is fixed to the operating spindle of the second vacuum interrupter. The linkage slide rod has a first limit groove and a second limit groove along its axial direction. When the first vacuum interrupter is in the closed position, the first crank arm engages in the first limit groove, and the second crank arm is blocked by the limit stop, keeping the second vacuum interrupter open. When the second vacuum interrupter is in the closed position, the second crank arm engages in the second limit groove, and the first crank arm is blocked by the limit stop, keeping the first vacuum interrupter open. This mechanical interlocking linkage ensures that the first and second vacuum interrupters are not simultaneously in the closed position, physically preventing parallel operation of the two power supplies.

[0105] The first and second switch actuators each include an electromagnetic closing / opening coil, a relay drive circuit, and a switch auxiliary contact feedback circuit. The relay drive circuit is electrically connected to the intelligent controller and drives the electromagnetic closing / opening coil to perform closing or opening operations according to the switching commands output by the intelligent controller. The switch auxiliary contact feedback circuit is also electrically connected to the intelligent controller and feeds back the actual position signal of the switch actuator to the intelligent controller. The electromagnetic closing / opening coil adopts a dual-coil structure, meaning the closing coil and opening coil are independently set and controlled by their respective relay drive circuits. When the closing coil is energized, it generates electromagnetic force to drive the switch mechanism to close; when the opening coil is energized, it generates electromagnetic force to drive the switch mechanism to open.

[0106] An independent hardware interlock circuit is also provided between the first and second switch actuators to ensure that at most one switch actuator is in the closed state at any given time, forming a double protection with the mechanical interlock linkage.

[0107] Example 10

[0108] like Figure 1 and Figure 2 As shown, the present invention also provides a control method for a dual-input, mutually redundant intelligent boundary switch, comprising the following steps:

[0109] Step S1: The voltage, current, frequency, and phase of the first and second power lines are acquired in real time through the power parameter acquisition module. Specifically, the first voltage transformer and the first current transformer acquire the voltage and current signals of the first power line, and the first energy metering chip performs analog-to-digital conversion and metering processing; the second voltage transformer and the second current transformer acquire the voltage and current signals of the second power line, and the second energy metering chip performs analog-to-digital conversion and metering processing; the metered data is then uploaded to the intelligent controller through the communication interface.

[0110] Step S2: Perform moving average filtering and true RMS calculation on the acquired voltage, current, frequency, and phase. The data acquisition and processing unit receives the raw data uploaded from the communication interface, processes the data according to the moving average filtering algorithm and the true RMS algorithm, eliminates sampling noise and harmonic interference, and obtains accurate voltage RMS values, current RMS values, frequency values, and phase angles.

[0111] Step S3: Based on the voltage, current, frequency, and phase after filtering and true RMS calculation, calculate the comprehensive power quality evaluation index for the first and second power supply lines respectively. and The power quality assessment unit calculates the power quality of each line according to the formula described in Example 4. value.

[0112] Step S4: Following the preset switching control strategy, a switching command is generated based on the comparison between the comprehensive power quality assessment index and the dynamic threshold. The switching decision unit then... and , and Based on the comparison results, a corresponding switching instruction is generated according to the switching control strategy described in Example 8.

[0113] Step S5: Before executing the closing operation, compare the voltage difference, frequency difference, and phase difference between the first and second power supply lines. The switching command is only allowed to take effect when all three conditions are met simultaneously. After the switching decision unit outputs the closing command and before the drive control unit executes the closing command, the synchronization detection unit performs synchronization checks on the two power supplies according to the synchronization conditions described in Example 6. The closing command is only allowed to take effect when all three conditions are met simultaneously.

[0114] Step S6: Drive the first or second switch actuator to perform a closing or opening operation according to the switching command. The drive control unit receives the effective switching command and drives the corresponding electromagnetic closing / opening coil through the first or second relay drive circuit to complete the opening / closing operation of the switch. At the same time, the first or second switch auxiliary contact feedback circuit feeds back the actual position signal of the switch to the intelligent controller to realize closed-loop control.

[0115] Example of a complete work scenario:

[0116] Scenario A – Main power supply is normal, single-phase grounding occurs on the user side: The intelligent controller detects that the effective value of the zero-sequence current is greater than the threshold value and the zero-sequence active power direction angle is... If the fault is determined to be a ground fault on the user side, the first switch actuator that was previously closed will be immediately tripped, the automatic transfer switch interlock flag will be set, and an interlock signal will be output. Because of the received automatic transfer switch interlock signal, even if the main power supply subsequently loses power, the automatic transfer switch will not be activated, preventing the backup power supply from being mistakenly connected to the faulty branch.

[0117] Scenario B – The main power supply's power quality has deteriorated but it has not completely lost power: The intelligent controller detects the first power line. (e.g., the voltage temporarily drops to 85% of the rated value for more than the set time), and the second power supply line If no backup automatic transfer interlock signal is received, the switching is performed: first, the first switch actuator is opened, and then the second switch actuator is closed, so as to realize the active switching from inferior power supply to superior power supply, rather than waiting for complete voltage loss before switching.

[0118] Scenario C – Main power supply completely lost, no fault on the user side: The intelligent controller detects a voltage drop in the first power line and If the confirmation time continues beyond the specified period, the second power supply line will have voltage and If no backup automatic transfer interlock signal is received, the backup automatic transfer switching is performed: first, the first switch actuator is opened, and then the mechanical interlock linkage is driven to close the second vacuum interrupter, thus completing the automatic switching of the dual incoming lines.

[0119] Based on the descriptions of embodiments one through ten above, the dual-input, mutually redundant intelligent boundary switch and its control method provided by the present invention have the following technical effects:

[0120] First, it enables early detection and optimized switching of gradually deteriorating power quality. This is achieved through a comprehensive power quality assessment index. By incorporating parameters from four dimensions—voltage, current, frequency, and phase—into a unified evaluation framework, the system can perceive the gradual deterioration trend of power quality in real time and make optimized switching decisions in advance before the power supply is completely lost, overcoming the limitation of traditional solutions that can only judge the binary state of "power on / power off".

[0121] Second, it achieves precise switching decisions for adaptive dynamic thresholds. Dynamic threshold The adaptive update mechanism enables the switching decision to be dynamically adjusted according to the historical fluctuations in power quality, avoiding misjudgments or omissions that may occur when the fixed threshold is large when the power quality fluctuates, thus improving the accuracy and robustness of the switching decision.

[0122] Third, it achieves directional fault detection and reliable interlocking of automatic backup power transfer on the user side. This is achieved through the zero-sequence active power direction angle. It accurately distinguishes between user-side faults and system-side faults, and outputs a backup automatic transfer interlock signal when a user-side fault occurs, preventing the backup power supply from being connected to the faulty branch. This solves the problem that the existing separate setting of the boundary switch and the backup automatic transfer interlock causes the backup automatic transfer interlock to malfunction and expand the power outage area due to user-side faults.

[0123] Fourth, it achieves strict synchronization detection and safety interlocking protection. By performing multi-dimensional synchronization verification on the voltage difference, frequency difference, and phase difference of the two power supplies before closing, it ensures that the electrical parameters of the two power supplies are highly consistent at the time of closing, thereby minimizing the closing inrush current.

[0124] Fifth, it achieves dual safety assurance through mechanical interlocking and electrical control. The mechanical interlocking linkage physically ensures that the first and second vacuum interrupters are not simultaneously in the closed position. Even if the intelligent controller malfunctions, the mechanical interlocking linkage can still effectively prevent the parallel operation of the two power supplies.

[0125] Sixth, a reliable physical structure suitable for outdoor environments has been achieved. The inclusion of an independent energy harvesting chamber, a sealed controller cavity, thermally conductive silicone, and a desiccant pack ensures the long-term stable operation of the intelligent controller in outdoor high-temperature, high-humidity environments.

[0126] The dual-input, mutually redundant intelligent boundary switch and its control method provided by this invention can be widely applied in the following scenarios:

[0127] In industrial parks, a large number of manufacturing enterprises with high requirements for power supply continuity are typically located within the park. A single power outage can cause the entire production line to shut down and result in huge economic losses. The intelligent sectionalizing switch of this invention can be installed on the incoming side of the 10kV distribution line in the park. It uses dual incoming lines to achieve power backup, and switches to the backup line in advance when the power quality of the main power line gradually deteriorates. At the same time, it has the ability to detect faults on the user side, preventing the backup power supply from being mistakenly connected to a faulty branch, thus ensuring the continuous production of enterprises in the park.

[0128] In data center scenarios, IT equipment such as servers have extremely high requirements for power quality and power supply continuity. The comprehensive power quality assessment function of this invention can ensure that servers always operate under high-quality power, extending equipment life; the millisecond-level switching capability can meet the stringent requirements of data centers for "zero power interruption".

[0129] In hospital settings, life support equipment in critical medical areas such as operating rooms and intensive care units must not be shut down. The intelligent boundary switch of this invention provides hospitals with reliable dual power supply protection, automatically and seamlessly switching to backup power when the main power supply quality deteriorates, ensuring continuous operation of medical equipment.

[0130] In transportation hub scenarios, lighting, communication, and signaling systems in locations such as airports, train stations, and subway stations require uninterrupted power supply. The intelligent boundary switch of this invention can provide highly reliable power supply for transportation hubs, preventing traffic chaos and safety accidents caused by power outages.

[0131] In summary, the dual-incoming-line mutual backup intelligent boundary switch and its control method provided by this invention realize the early detection and optimized switching of gradual degradation of power quality of dual power sources at the end of the distribution network, as well as the accurate identification and reliable blocking of user-side faults, and have significant technical advantages and wide industrial applicability.

[0132] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-input, mutually redundant intelligent boundary switch, characterized in that, include: The first incoming line interface is used to connect to the first power supply line; The second incoming line interface is used to connect to the second power supply line; Outgoing interface, used to connect to the load line; The first switch actuator is connected between the first incoming interface and the outgoing interface, and is used to control the connection and disconnection between the two. The second switch actuator is connected between the second inlet interface and the outlet interface, and is used to control the connection and disconnection between the two. The power parameter acquisition module is electrically connected to the first incoming interface and the second incoming interface respectively, and is used to acquire the voltage, current, frequency and phase of the first power line and the second power line in real time. A human-computer interaction display terminal is used to display the operating parameters of the first power line and the second power line, as well as the switching status of the two switch actuators; The intelligent controller is electrically connected to the power parameter acquisition module, the two switch actuators, and the human-machine interface display terminal, respectively, and is used for: The power quality comprehensive evaluation index is dynamically calculated based on the voltage, current, frequency and phase. Based on the comparison result of the power quality comprehensive evaluation index and the dynamic threshold, the two switch actuators are controlled to perform closing or opening operations to realize dual-incoming line mutual backup switching. The zero-sequence active power direction angle is calculated based on the zero-sequence voltage and zero-sequence current at the outgoing interface. When the zero-sequence active power direction angle falls into the preset user-side fault direction angle range, the currently closed switch actuator is controlled to open and output a backup automatic transfer interlocking signal.

2. The dual-input, mutually redundant intelligent boundary switch according to claim 1, characterized in that, The intelligent controller includes: The data acquisition and processing unit is electrically connected to the power parameter acquisition module and is used to receive and parse the voltage, current, frequency and phase uploaded by the power parameter acquisition module, and to perform moving average filtering and true RMS calculation on the received signals. The power quality assessment unit is electrically connected to the data acquisition and processing unit and is used to calculate the comprehensive power quality assessment index of the first power line and the second power line based on the voltage, current, frequency and phase after filtering and true RMS calculation. The switching decision unit is electrically connected to the power quality assessment unit and is used to generate a switching command according to a preset switching control strategy based on the comparison result of the power quality comprehensive assessment index and the dynamic threshold. The synchronization detection unit is electrically connected to the switching decision unit and is used to compare the voltage difference, frequency difference and phase difference between the first power line and the second power line before performing the closing operation. The closing command output by the switching decision unit is allowed to take effect only when the voltage difference, frequency difference and phase difference all meet the preset synchronization closing conditions. The drive control unit is electrically connected to the switching decision unit, the first switch actuator, and the second switch actuator, respectively, and is used to drive the first switch actuator or the second switch actuator to perform closing or opening operations according to the switching command.

3. The dual-input, mutually redundant intelligent boundary switch according to claim 2, characterized in that, The intelligent controller also includes: The interlocking protection unit is electrically connected to the drive control unit and is used to output an interlocking signal to the drive control unit within a preset interlocking action time when a short circuit fault is detected in the first power line or the second power line, thereby prohibiting the switch actuator of the corresponding line from performing a closing operation.

4. The dual-input, mutually redundant intelligent boundary switch according to claim 2, characterized in that, The comprehensive power quality assessment index is dynamically calculated according to the following formula: ； in, express The comprehensive power quality assessment index at any given time; express The real-time effective value of the voltage at any given moment; Indicates the rated voltage value; express The real-time RMS value of the current at any given moment; Indicates the rated current value; express Real-time frequency value at any given moment; Indicates the rated frequency value; express Real-time phase angle at any given moment; , , , These are the voltage weighting coefficient, current weighting coefficient, frequency weighting coefficient, and phase weighting coefficient, respectively. .

5. The dual-input, mutually redundant intelligent boundary switch according to claim 4, characterized in that, The dynamic threshold is updated dynamically in the following manner: ； in, express The dynamic threshold at any given time; This indicates the preset baseline threshold. This represents the adaptive adjustment coefficient; Indicates the length of the sliding window; express The comprehensive power quality assessment index at any given time; This represents the average value of the comprehensive power quality assessment index within the sliding window.

6. The dual-input, mutually redundant intelligent boundary switch according to claim 5, characterized in that, The benchmark threshold The adaptive adjustment coefficient is calculated by taking the 5th percentile of the comprehensive power quality assessment index during the historical normal operation period of the line. The range of values ​​is to The length of the sliding window The range of values ​​is to One sampling period.

7. The dual-input, mutually redundant intelligent boundary switch according to claim 2, characterized in that, The conditions for synchronous closing are as follows: ； ； ； in, and These represent the real-time effective voltage values ​​of the first power supply line and the second power supply line, respectively. and These represent the real-time frequency values ​​of the first power line and the second power line, respectively. and These represent the real-time phase angles of the first power line and the second power line, respectively. This indicates the preset voltage deviation allowable coefficient; This indicates the preset allowable frequency deviation coefficient; This indicates the preset allowable phase deviation value.

8. The dual-input, mutually redundant intelligent boundary switch according to claim 1, characterized in that, The intelligent controller calculates the zero-sequence active power direction angle according to the following formula: ； in, Indicates the direction angle of zero-sequence active power; express The instantaneous value of the zero-sequence voltage at time t; express The instantaneous value of the zero-sequence current at time t; express Hilbert transform; Indicates the power frequency period; Represents the imaginary unit; The zero-sequence voltage and the zero-sequence current are obtained by a zero-sequence voltage sensor and a zero-sequence current transformer installed at the outgoing interface; the preset user-side fault direction angle range is... .

9. The dual-input, mutually redundant intelligent boundary switch according to claim 8, characterized in that, The intelligent controller operates when the effective value of the zero-sequence current is greater than the zero-sequence action threshold and the zero-sequence active power direction angle is... Falling into the preset user-side fault direction angle range When the fault occurs, it is determined to be a grounding fault on the downstream user side of the outgoing interface; the zero-sequence action threshold value is determined according to... Adjustment, among which The reliability coefficient is set to a value of [value missing]. to , This is the effective value of the zero-sequence current corresponding to the maximum capacitive current when the system is operating normally.

10. The dual-input, mutually redundant intelligent boundary switch according to claim 2, characterized in that, The preset switching control strategy is as follows: When the comprehensive power quality evaluation index of the first power supply line is greater than or equal to the dynamic threshold, the first switch actuator is controlled to be in the closed state and the second switch actuator is controlled to be in the open state. When the comprehensive power quality evaluation index of the first power supply line is less than the dynamic threshold and the comprehensive power quality evaluation index of the second power supply line is greater than or equal to the dynamic threshold, the first switch actuator is controlled to perform a tripping operation and the second switch actuator is controlled to perform a closing operation. When the comprehensive power quality evaluation index of both the first power line and the second power line is less than the dynamic threshold, the first switch actuator and the second switch actuator are both controlled to be in the open state.

11. The dual-input, mutually redundant intelligent boundary switch according to claim 1, characterized in that, The outer casing of the dual-input backup switch body is provided with a first energy harvesting compartment and a second energy harvesting compartment. The first energy harvesting compartment is fixedly provided with a first voltage energy harvesting unit connected in parallel between the first input terminal and the ground wire. The second energy harvesting compartment is fixedly provided with a second voltage energy harvesting unit connected in parallel between the second input terminal and the ground wire. A sealed controller cavity is fixedly connected to the lower part of the outer casing. The intelligent controller is encapsulated in the sealed controller cavity. The sealed controller cavity is filled with thermally conductive silicone and the inner wall is attached with a desiccant pack.

12. The dual-input, mutually redundant intelligent dividing switch according to claim 11, characterized in that, The dual-input backup switch body includes a first vacuum interrupter, a second vacuum interrupter, and a mechanical interlocking linkage. The mechanical interlocking linkage includes a first crank arm, a second crank arm, a linkage slide rod, and a limit stop. The first crank arm is fixedly connected to the operating spindle of the first vacuum interrupter, and the second crank arm is fixedly connected to the operating spindle of the second vacuum interrupter. The linkage slide rod has a first limit groove and a second limit groove along its axial direction. When the first vacuum interrupter is in the closed position, the first crank arm is inserted into the first limit groove, and the second crank arm is blocked by the limit stop, keeping the second vacuum interrupter open. When the second vacuum interrupter is in the closed position, the second crank arm is inserted into the second limit groove, and the first crank arm is blocked by the limit stop, keeping the first vacuum interrupter open.

13. A control method for a dual-input, mutually redundant intelligent boundary switch, characterized in that, Includes the following steps: The voltage, current, frequency, and phase of the first and second power lines are collected in real time by the power parameter acquisition module. The collected voltage, current, frequency, and phase are processed by moving average filtering and true RMS value calculation. Based on the voltage, current, frequency, and phase after filtering and true RMS calculation, the comprehensive power quality evaluation index of the first power supply line and the second power supply line is calculated respectively. According to the preset switching control strategy, a switching command is generated based on the comparison result between the comprehensive power quality assessment index and the dynamic threshold. Before performing the closing operation, the voltage difference, frequency difference, and phase difference between the first power line and the second power line are compared, and the switching command is allowed to take effect only when the voltage difference, frequency difference, and phase difference all meet the preset synchronous closing conditions. The switching command drives the first or second switch actuator to perform closing or opening operations.

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