Intelligent power distribution circuit system for digitized ring main unit

Abstract

The application relates to the technical field of auxiliary power supply control of power distribution automation, and discloses an intelligent power distribution circuit system for a digitalized ring network cabinet, which comprises a transient voltage gradient induction bridge circuit, a hardware signal processing circuit, a power switch unit and a controlled energy release unit. The system collects the voltage change rate signal of the primary side bus by using the transient voltage gradient induction bridge circuit, the hardware signal processing circuit performs the derivation operation on the induction signal and compares the induction signal with the voltage gradient threshold value, the power switch unit is locked at the moment of voltage abnormal drop to cut off the load current path, and the dehumidification and heating resistance is synchronously driven to be turned on to release the overcharge, the hardware parameter direct mapping mechanism is used to realize the microsecond-level transient protection response, the inherent dehumidification resistance in the multiplexing cabinet is used to balance the bus potential pulse caused by the sudden discharge of the load, and the physical decoupling of the protection logic and the digitalized software is realized.

Description

Technical Field

[0001] This invention relates to an intelligent power distribution circuit system for digital ring main units, belonging to the field of auxiliary power supply control technology for power distribution automation. Background Technology

[0002] Current digital ring main units integrate high-power wireless communication terminals and edge computing units. The stability of the auxiliary power supply system determines the operational reliability of secondary precision equipment. Existing auxiliary power management mostly uses microprocessor software to sample and issue load shedding commands. During transient processes such as short-circuit faults, inrush currents during reclosing, or lightning strikes in the primary distribution circuit, the voltage drop rate reaches the microsecond level. The delay in the detection, calculation, and execution logic of the digital solution causes the load shedding action to lag behind the discharge rate of the DC bus support capacitor. Before the system operates, the bus voltage drops below the operating threshold of the relay protection unit, causing the secondary precision equipment to lose power.

[0003] Increasing capacitor capacity or using parallel transient suppression devices to compensate for delays is limited by the physical space inside the ring main unit. Furthermore, the sudden load shedding effect during high-power load disconnection causes transient overshoot voltage and heat accumulation on the bus, affecting the service life of semiconductor devices. The physical parameters of sensing devices are subject to long-term drift due to temperature and humidity fluctuations. The transient interference defense capability of the auxiliary power supply system restricts the self-healing performance of distribution nodes, and existing hardware protection schemes have limitations in their response mechanisms. For example, the utility model patent with authorization announcement number CN210111599U discloses a ring main unit... Passive trip protection devices, with auxiliary power modules equipped with pressure relief circuits, utilize varistors and bidirectional thyristors to release overvoltage energy. This type of solution relies on the accumulation of the absolute amplitude of fault characteristic quantities to a specific threshold to trigger action. Although the amplitude triggering logic keeps the entire action time within 90ms, it still cannot match the microsecond-level voltage transient drop speed of the distribution network. Hard switching energy relief methods are prone to causing secondary voltage backlash and thermal stress impact on the DC bus when disconnecting loads, making it difficult to meet the power supply stability and microsecond-level response speed requirements of high-precision equipment in digital ring main units.

[0004] Therefore, how to construct a hardware energy routing mechanism that is independent of microprocessor logic, has a microsecond-level physical response speed, and adapts to the bus energy state, in order to solve the problem of auxiliary power supply failure of digital ring network cabinets under transient interference, has become the technical problem to be solved by this invention. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: An intelligent power distribution circuit system for a digital ring main unit, comprising an auxiliary power supply bus, a transient voltage gradient induction bridge, a hardware signal processing circuit, a power switching unit, and a controlled energy discharge unit; the auxiliary power supply bus has a first energy output port and a second energy output port, the first energy output port being connected to the core protected load, and the second energy output port being connected to the non-core digital load; the system follows the following physical operating rules:

[0006] The transient voltage gradient induction bridge is coupled between the high-voltage port of the primary distribution circuit and the reference ground potential of the ring main unit, and is used to collect the first derivative induction signal reflecting the rate of change of the primary bus voltage;

[0007] The hardware signal processing circuit is connected to the transient voltage gradient sensing bridge and the power switching unit respectively. It includes an analog derivative and a window comparator. The analog derivative performs slope mapping processing on the first derivative sensing signal to generate a first-order voltage change rate level. The window comparator compares the first-order voltage change rate level with a preset voltage gradient threshold.

[0008] The power switch unit is connected in series in the power supply circuit of the second energy output port, and a pre-closing detection branch composed of current-limiting sampling resistors is connected in parallel across the two ends of the power switch unit.

[0009] The controlled energy dissipation unit includes a dehumidifying heating resistor and a controlled switching transistor installed in the ring main unit. The dehumidifying heating resistor is connected between the positive and negative terminals of the auxiliary power supply bus through the controlled switching transistor.

[0010] When the first-order voltage change rate exceeds the voltage gradient threshold, the hardware signal processing circuit blocks the drive level of the power switching unit to cut off the current path of non-core digital loads, and synchronously outputs a high-level signal to drive the controlled switch to turn on, so that the transient charge of the auxiliary power supply bus is introduced into the dehumidification heating resistor and converted into heat energy.

[0011] During the period when the power switch unit is in the off state, the hardware signal processing circuit obtains the feedback voltage rise slope of the second energy output port through the pre-closing detection branch, and restores the drive level of the power switch unit only when the feedback voltage rise slope exceeds the preset closing ready threshold.

[0012] Preferably, the system further includes a reference automatic calibration circuit; the reference automatic calibration circuit is used to extract the power frequency fundamental component in the first derivative induction signal, and proportionally correct the voltage gradient threshold in the hardware signal processing circuit according to the amplitude change of the power frequency fundamental component, so as to offset the induced impedance drift of the transient voltage gradient induction bridge.

[0013] Preferably, the transient voltage gradient induction bridge circuit includes a first induction branch, a second induction branch, and a differential operational amplifier circuit; the first induction branch is coupled to the primary side bus, and the second induction branch is coupled to the reference ground potential of the ring main unit; the input terminals of the differential operational amplifier circuit are respectively connected to the first induction branch and the second induction branch, and are used to perform analog subtraction operation on the acquired primary side grid signal and the environmental common-mode noise signal to generate a first-order derivative induction signal with differential mode properties.

[0014] Preferably, the hardware signal processing circuit includes a self-reset delay module composed of resistors and capacitors; the self-reset delay module is connected to the output of the window comparator and is used to maintain the power switch unit in the off state until the preset physical cooling cycle ends after the first-order voltage change rate level recovers to below the voltage gradient threshold.

[0015] Preferably, a supporting capacitor bank is connected in parallel between the positive and negative terminals of the auxiliary power supply bus. The supporting capacitor bank is used to maintain the voltage stability of the first energy output port by utilizing its stored charge during the power switching unit's off period.

[0016] Preferably, the voltage gradient threshold is based on the discharge slope limit value of the auxiliary power supply bus. Set the discharge slope limit value. The following calculation rules apply: ,in, To provide an upper limit for the allowable voltage drop rate of the auxiliary power supply bus under transient operating conditions, This is the system's preset total load current rating. This is the rated current value of the first energy output port. To support the equivalent capacitance value of the capacitor bank.

[0017] Preferably, the power switch unit is connected to an overcurrent lockout circuit; the overcurrent lockout circuit is used to forcibly block the drive level of the power switch unit when the real-time load current value at the second energy output port exceeds a preset overload limit.

[0018] Preferably, a fast charge discharge circuit is connected in the drive circuit of the controlled switch. The fast charge discharge circuit is used to extract the gate charge of the controlled switch when the hardware signal processing circuit removes the high level of drive.

[0019] Preferably, the analog derivative includes an operational amplifier and a differential capacitor connected in the feedback loop of the operational amplifier, which converts the first derivative induced signal into a first-order voltage rate of change level through the charging and discharging characteristics of the differential capacitor.

[0020] Preferably, the hardware signal processing circuit determines whether the charge reserve status of the auxiliary power supply bus has the rigidity to support the inrush current of non-core digital loads based on the comparison result of the feedback voltage rise slope and the closing ready threshold.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. In intelligent power distribution circuits, transient slope sensing bridge circuits, in conjunction with analog logic processing circuits, directly extract voltage gradient signals from the induced voltage of the primary bus and convert physical characteristics into power arbitration circuit switching drive commands. This ensures that the physical disconnection response of non-core digital loads is synchronized with the voltage drop process at the microsecond level, avoiding response delays caused by processor software sampling and logic judgment. Load disconnection is completed before a large amount of charge is lost from the DC bus support capacitor, ensuring the continuity of energy supply to core protected loads.

[0023] 2. When the hardware arbitration control module drives the controlled switch unit to turn off the non-core digital load, it simultaneously grounds the controlled DC bus through the dehumidifying heating resistor. It uses the inherent thermal inert components in the distribution cabinet to absorb the inductive backlash energy generated at the moment of the non-core digital load being turned off. Through the function multiplexing mechanism, it balances the transient overshoot voltage of the bus caused by the sudden load unloading. When the potential balance of the auxiliary power supply bus is stabilized, the transient electrical energy is converted into heat energy and released, reducing the overvoltage stress and heat loss of the power semiconductor devices.

[0024] 3. The reference self-calibration circuit extracts the power frequency component from the output signal of the transient slope sensing bridge circuit. Based on the amplitude of the power frequency component, it adjusts the judgment threshold of the analog logic processing circuit in real time, so that the action sensitivity is anchored to the inherent frequency characteristics of the power grid and the physical coupling efficiency of the sensing device. It automatically compensates for the long-term drift of the physical parameters of the sensing bridge circuit caused by the alternation of ambient temperature and humidity, maintains the stability of the protection trigger accuracy throughout the entire life cycle of the equipment, and reduces the frequency of manual on-site calibration and maintenance costs. Attached Figure Description

[0025] Figure 1 This is a diagram illustrating the hardware architecture and signal flow of the intelligent power distribution circuit of this invention.

[0026] Figure 2 This is a mapping diagram of adaptive threshold correction and physical parameter alignment in this invention;

[0027] Figure 3 This is a timing diagram of the transient energy routing and power supply self-healing logic of the present invention. Detailed Implementation

[0028] The following embodiments are intended to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0029] This invention proposes an intelligent power distribution circuit system for digital ring main units, including an auxiliary power supply bus, a transient voltage gradient induction bridge, a hardware signal processing circuit, a power switching unit, and a controlled energy discharge unit. The auxiliary power supply bus has a first energy output port and a second energy output port. The first energy output port is connected to core protection loads such as relay protection devices, and the second energy output port is connected to non-core digital loads such as communication terminals and edge computing units. The transient voltage gradient induction bridge is coupled between the high-voltage port of the primary side distribution circuit and the reference ground potential of the ring main unit, and is used to extract the first derivative induction signal reflecting the rate of change of the primary side bus voltage in real time. The hardware signal processing circuit is connected to the transient voltage gradient induction bridge and the power switching unit respectively, and determines the voltage fluctuation state through analog logic. The power switching unit is connected in series with the second energy output port. In the power supply circuit of the port, the controlled energy discharge unit is connected between the positive and negative poles of the auxiliary power supply bus to absorb transient overshoot energy at the moment of load disconnection. In order to solve the problem of malfunction caused by high-frequency switching noise inside the digital ring main unit, the system uses the symmetrical differential topology of the transient voltage gradient induction bridge to achieve signal purification. The transient voltage gradient induction bridge includes a first induction branch, a second induction branch, and a differential operational amplifier circuit. The first induction branch is connected to the primary bus through capacitive coupling, and the second induction branch is connected to the reference ground potential inside the ring main unit. The differential operational amplifier circuit receives the two induction levels and cancels the common-mode noise generated by the switching power supply inside the unit through analog subtraction. This physical circuit configuration makes the induction signal reflect the real transient characteristics of the primary side of the power grid and outputs a stable first-order derivative induction signal to the hardware signal processing circuit.

[0030] To address the challenge of load shedding lag caused by microprocessor software sampling delay, the hardware signal processing circuit employs a hardware differentiation and comparison mechanism composed of analog operational amplifiers, including an analog differentiater and a window comparator. The analog differentiater performs slope mapping on the first-order derivative induced signal to generate a first-order voltage change rate level. The window comparator compares this level with a preset voltage gradient threshold. In specific numerical application scenarios, when the primary bus voltage drop rate reaches... When the analog derivative outputs the corresponding voltage change rate level, if the level exceeds the set voltage gradient threshold, the hardware signal processing circuit blocks the drive level of the power switch unit and cuts off the current path of the non-core digital load. This process avoids the instruction cycle of the microprocessor, so that the load shedding response and the voltage drop process are synchronized at the microsecond level, ensuring the power supply continuity of the core protected load before the bus charge is lost.

[0031] Based on the load shedding effect caused by the instantaneous disconnection of high-power loads, the controlled energy discharge unit reuses the dehumidifying heating resistor in the ring main unit as a dynamic energy-consuming load, including the dehumidifying heating resistor and the controlled switch. The hardware signal processing circuit, while blocking the power switching unit, simultaneously outputs a high-level signal to drive the controlled switch to conduct, allowing the transient charge from the auxiliary power supply bus to be directed to the dehumidifying heating resistor and discharged as heat. The voltage gradient threshold is based on the discharge slope limit value of the auxiliary power supply bus. The limit value is set to meet the following calculation rules: ,in, The upper limit of the allowable voltage drop rate of the auxiliary power supply bus under transient operating conditions; This is the system's preset total load current rating. This is the rated current value of the first energy output port; To improve the equivalent capacitance of the capacitor banks supporting the auxiliary power supply bus, this thermoelectric synergy mechanism reduces the voltage stress on the power semiconductor devices and stabilizes the potential of the auxiliary power supply bus; the delay time of the self-reset delay module... The calibration procedure is performed based on the thermal decay characteristics of the dehumidifying heating resistor, and its value satisfies the following requirements. Not less than The proportional term of multiples ,in, The preset reliability coefficient, The heat capacity of the dehumidifying heating resistor; The proportional relationship between the resistor and the heat dissipation conductivity of the ring main unit environment is determined by offline measurement of the time span of the resistor cooling from the maximum allowable temperature to the environmental equilibrium state, thereby achieving phase alignment of the system reset action and the physical cooling process in the time dimension.

[0032] Example 1: In an industrial power distribution terminal with a high inductive load, when a microsecond-level voltage transient drop occurs in the primary power distribution circuit due to a short circuit fault or the starting of a large-capacity motor, the high-power communication module and edge computing unit inside the digital ring main unit are still operating at rated power, causing the rated total load current carried by the auxiliary power supply bus to exceed the rated value. When the load reaches full capacity, a response blind zone occurs where the voltage drop rate exceeds the software sampling period. The transient voltage gradient sensing bridge uses a capacitively coupled branch to extract the primary bus voltage change rate signal in real time and convert it into a first-order derivative sensing signal. This signal is then input to the analog derivative in the hardware signal processing circuit for slope mapping and outputs a first-order voltage change rate level that reflects transient characteristics. When this level instantaneously exceeds a preset voltage gradient threshold, the window comparator directly blocks the drive pulse of the power switch unit, cutting off the non-core digital load current path connected to the second energy output port. Simultaneously with this shutdown action, the hardware signal processing circuit drives the controlled switch in the controlled energy discharge unit to conduct, allowing the transient surplus charge of the auxiliary power supply bus to be introduced into the dehumidification heating resistor for energy conversion. The thermal characteristics of this resistor are used to suppress the bus potential backlash fluctuation caused by the rapid load shedding.

[0033] Supported by the energy of the supporting capacitor bank, the auxiliary power supply bus maintains the continuity of power supply from the first energy output port to the relay protection device, and its voltage drop rate is limited by: Within a defined range, The upper limit of the allowable voltage drop rate of the auxiliary power supply bus under transient operating conditions; The system is preset with a total load current rating; This is the rated current value of the first energy output port; To support the equivalent capacitance value of the capacitor bank, the reference automatic calibration circuit monitors the amplitude change of the power frequency fundamental component, corrects the voltage gradient threshold of the window comparator in real time, and compensates for the impedance drift of the induced branch caused by changes in ambient humidity. During the reclosing recovery phase after fault clearance, the pre-closing detection branch injects a probe current into the load side through the current-limiting sampling resistor to determine that the feedback voltage rise slope meets the closing ready threshold. While avoiding the voltage drop energy blind zone, the system restores controlled power supply based on the physical verification results of the charge intensity of the auxiliary power supply bus.

[0034] Example 2: The experimental data provided in this example are used to verify the physical characteristic mapping effect and power supply continuity performance of the intelligent power distribution circuit system of the present invention under specific operating conditions, and are not intended to limit the scope of protection of the present invention; the test platform is constructed in a physical laboratory simulating the transient environment of a high-voltage power distribution network, and includes an output capacity of The high-voltage pulse generator and the core protection load consisting of relay protection devices were tested, and the data were obtained through a sampling rate of [missing information]. And the amplitude resolution is The high-speed sampling system was used to acquire the signal, which was used to simulate random fluctuations in the industrial electromagnetic environment. The signal-to-noise ratio superimposed in the signal source was [value missing]. Gaussian noise and frequency of The voltage gradient threshold value for power frequency interference is determined based on a physical trade-off between the energy storage margin of the auxiliary power supply bus and the load shedding speed. Its value tends to ensure that the bus potential is not lower than the minimum operating voltage of the relay protection device before the load shedding is completed. In this experiment, the rated current of the core protection load is... for The equivalent capacitance value of the supporting capacitor bank for According to the formula The maximum allowable discharge slope of the busbar is determined to be Then, the voltage gradient threshold level was determined through circuit debugging. ,in, The maximum allowable discharge slope of the busbar; The system's preset total load current rating is set to [value] in this test. ; The rated current of the core protected load; To support the equivalent capacitance value of the capacitor bank; the slope of the simulated primary bus drop is... During a short-circuit fault, a comparative study was conducted on the action time of a control group using a microprocessor sampling method and a sample group using the hardware logic of this invention. The control group was limited by... The computation instruction cycle generates The delayed cut-off caused the bus voltage to drop to When a core protection load loses power, the prototype of this invention, after the transient voltage gradient sensing bridge circuit captures the signal, [is affected]. This means shutting off the current path of non-core digital loads and maintaining the bus voltage at... .

[0035] Table 1: Comparison of System Protection Performance under Power Grid Transient Impacts

[0036]

[0037] As the voltage drop slope gradient increases, the response time of the sample group of this invention stabilizes at... Within this range, it exhibits a direct mapping capability to physical characteristics, even when the drop intensity reaches... At the performance inflection point, the dehumidifying heating resistor absorbs the surplus charge of the busbar and generates The temperature rise suppressed the bus potential backlash, confirming the stability of the hardware energy routing mechanism within a microsecond window. The automatic calibration circuit of the reference was tested under ambient humidity conditions. Rise to During the process, the amplitude of the power frequency fundamental wave was monitored from Rise to It also adjusts the voltage gradient threshold in real time to maintain the triggering error within a certain range. Within this range, during the reclosing phase, the pre-closing detection branch determines that the rise slope of the feedback voltage meets the closing readiness threshold by detecting the current. The system then restores power supply based on the physical verification results of the bus charge strength, thus avoiding secondary power outages caused by insufficient charge reserves.

[0038] Example 3: This example combines Figures 1 to 3 A description of an intelligent power distribution circuit system for a digital ring main unit, such as... Figure 1 As shown, a transient voltage gradient induction bridge is coupled between the high-voltage port of the primary distribution circuit and the reference ground to collect the primary bus voltage change rate signal. The generated induction signal enters the hardware signal processing circuit for differentiation and threshold comparison to generate control commands. The control commands include a blocking drive level for the power switch unit and a drive turn-on signal for the controlled energy discharge unit. The power switch unit is connected in series in the second energy output port circuit and blocks at the moment of voltage drop to disconnect the non-core digital load connected to the port. The controlled energy discharge unit drives the dehumidification heating resistor to conduct through the controlled switch tube to discharge overshoot charge. The auxiliary power supply bus serves as an energy collection and distribution node, with the controlled energy discharge unit between its positive and negative poles, and the core protection load is connected through the first energy output port to ensure power supply continuity.

[0039] like Figure 2 As shown, the system uses an automatic reference calibration circuit to compensate for the judgment threshold in real time. The horizontal axis represents the change in the fundamental frequency amplitude from 1.8V to 3.0V, and the vertical axis represents the voltage value in V. The figure specifically shows the fundamental frequency amplitude V and the voltage gradient threshold correction amount, which have a linear mapping relationship. In addition to the three sets of characteristic curves for the corrected threshold V, when the effective value of the power frequency component shifts due to environmental conditions or power grid fluctuations, the system extracts the compensation component in real time based on the degree of drift in the induced impedance. This is then applied to the reference terminal of the window comparator, causing the corrected threshold to exhibit a synchronous linear shift trend with the increase of the fundamental frequency amplitude, thereby achieving dynamic alignment of the judgment benchmark within the voltage coordinate system; such as Figure 3 As shown, when a transient signal is input from the primary distribution network interference / energy source, the system collects the voltage change rate and transient sensing, and processes it by hardware differentiation and comparison, and threshold determination. When the signal exceeds the threshold, it synchronously executes actions such as blocking the power switch, disconnecting the load, and driving the dehumidification resistor to conduct and discharge overcharge. In this process, while maintaining the core power supply, ensuring the operation of the core protected load and relay protection device at the first port, it physically cuts off the path to non-core digital loads, communication, and edge computing until it enters the pre-closing detection and recovery, slope verification stage. After determining that the feedback voltage rise slope meets the closing readiness requirements, it restores the power supply and maintains the power supply to the digital load and the power output of the second port.

[0040] Example 4: The technical solution provided in this example is used to explain the specific calibration procedure and parameter mapping path of the simulated hardware logic in this invention; when the digital ring main unit operates in an environment with humidity exceeding Under high humidity conditions, the coupling branch of the transient voltage gradient induction bridge circuit experiences impedance drift. The automatic calibration circuit extracts the effective value of the power frequency fundamental component from the primary-side induction signal. The proportional amplifier is based on The degree of deviation from the preset reference induced voltage adjusts the reference potential of the comparator, and the correction amount of the reference potential. The following calculation rules apply: ,in, This is the reference potential compensation amount for the window comparator; This is the sensing gain constant of the hardware circuit, and its value is set through the feedback resistor network parameters of the proportional multiplier. This refers to the real-time extracted effective value of the power frequency component voltage; The reference induced level under standard conditions is the first-order derivative gain of the analog derivative with respect to the rate of change of the primary bus voltage. Set at to Within the range, the slope of the primary bus voltage drop is converted to... to The logic judgment level is received by the window comparator and compared with the superimposed compensation amount. The voltage gradient threshold is compared, and when the judgment result exceeds the boundary, a logic signal is directly output to block the power switching unit. This mapping procedure based on the transfer function of analog devices makes the triggering accuracy of the sensing logic independent of the microprocessor's instruction execution cycle, compensates for impedance fluctuations caused by changes in ambient humidity, and maintains the consistency of protection actions throughout the equipment's service life.

[0041] After receiving the blocking logic signal, the gate drive voltage of the main power MOSFET is changed by the power switching unit. Instantaneous drop The power supply path to non-core digital loads is cut off. During this process, the hardware signal processing circuit synchronously drives the controlled switch of the controlled energy dissipation unit to saturate and conduct, directing the recoil charge generated by the supporting capacitor banks at both ends of the auxiliary power supply bus to the dehumidification heating resistor. The dehumidification heating resistor absorbs the transient surplus energy through ohmic energy dissipation, maintaining the potential fluctuation amplitude of the auxiliary power supply bus at a certain level. Within this system, a closed-loop feedback control circuit composed of operational amplifiers is used to convert environmental coupling interference into real-time displacement of the reference potential. Combined with a passive differentiation network composed of resistors and capacitors, the sampling timeliness obstacle of the software algorithm in the face of microsecond-level voltage changes is eliminated, ensuring the power supply stability of the core protected load during the transient process of primary side faults.

[0042] Example 5: In the deployment of a newly built power distribution node in a digital ring main unit, a reference alignment procedure is implemented for the transient voltage gradient induction bridge circuit to compensate for parasitic coupling deviations caused by internal metal components. The on-site commissioning steps utilize voltage accuracy not lower than... The external test power supply injects a frequency of [frequency value] into the primary bus. Furthermore, the amplitude of the stable sinusoidal reference voltage is monitored in real time, and the output level feedback of the hardware signal processing circuit is monitored when the auxiliary power supply bus is in an unloaded state, with a standard induced level. For continuous The arithmetic mean of the induced amplitude over one power frequency cycle is stored in the reference register of the proportional amplifier and used in the scaling factor. The mapping calculation enables the first-order derivative gain of the analog derivative to reach physical equilibrium under the initial environmental conditions.

[0043] When the system faces situations where supporting capacitor bank components need replacement or performance degradation, the physical charge detection procedure is implemented to determine the actual equivalent capacitance value of the auxiliary power supply bus. After completing the recalibration and debugging process, the constant current accuracy was better than that of the standard. A controlled constant current source injects into the auxiliary power supply bus. Current, monitoring auxiliary power supply bus at Voltage change over time To determine the charge carrying capacity, where The equivalent capacitance value is calculated based on the bus terminal voltage difference at the start and end times of constant current injection. Discharge slope limit value The dynamic updates ensure that the trigger threshold of the controlled energy discharge unit is consistent with the real-time state of the bus energy storage stiffness, and the potential fluctuation amplitude of the auxiliary power supply bus at the moment of load cut-off is within the safe voltage range of the semiconductor device.

[0044] Example 6: Under the condition of continuous overcurrent from an external load at the simulated second energy output port, the overcurrent lockout circuit connected to the power switch unit monitors the real-time load current value. When it reaches... When the current within the judgment window is consistently higher than the overload limit determined by the rated current of the power MOSFET, the locking circuit forcibly blocks the drive signal of the power switch unit through the logic interlock level. This process, in conjunction with the charge discharge circuit of the gate of the controlled switch, keeps the cut-off action of the main power transistor synchronized with the overcurrent characteristic detection process, avoiding the risk of hardware damage caused by permanent short circuit on the load side.

[0045] While maintaining power supply to the core protected load, the auxiliary power supply bus monitors the thermal state changes of the energy leakage branch through a self-reset delay module. It determines the evolution of the physical cooling cycle by using the temperature signal collected by the thermistor. When the real-time temperature of the dehumidifying heating resistor drops from the overshoot peak value to below the preset safety balance threshold, the delay module cancels the forced locking state of the window comparator. The power switching unit attempts to reclose the circuit based on the feedback slope of the pre-closing detection branch. This logic circuit achieves closed-loop locking of thermal protection at the physical level, allowing the reconnection process of non-core loads to avoid the underdamped oscillation zone of the primary power grid and eliminating the secondary power outage impact at the initial stage of reclosing.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An intelligent power distribution circuit system for digitized ring main unit, comprising an auxiliary power bus, a transient voltage gradient sensing bridge, a hardware signal processing circuit, a power switch unit and a controlled energy dissipation unit; the auxiliary power bus has a first energy output port and a second energy output port, the first energy output port is connected to a core protection load, and the second energy output port is connected to a non-core digital load; characterized in that, The system follows the following physical operation rules: The transient voltage gradient induction bridge is coupled between the high voltage port of the primary side distribution circuit and the reference ground potential of the ring main unit, and is used to collect a first derivative induction signal reflecting the voltage rate of change of the primary side bus; The hardware signal processing circuit is connected with the transient voltage gradient induction bridge and the power switch unit, and includes an analog differentiator and a window comparator; the analog differentiator performs slope mapping processing on the first derivative induction signal to generate a first voltage rate of change level, and the window comparator compares the first voltage rate of change level with a preset voltage gradient threshold value; The power switch unit is connected in series in the power supply circuit of the second energy output port, and a pre-close detection branch composed of a current limiting sampling resistor is connected in parallel at both ends of the power switch unit; The controlled energy release unit includes a dehumidification heating resistor arranged in the ring main unit and a controlled switch tube, and the dehumidification heating resistor is connected in parallel between the positive and negative poles of the auxiliary power supply bus through the controlled switch tube; When the first voltage rate of change level exceeds the voltage gradient threshold value, the hardware signal processing circuit blocks the drive level of the power switch unit to cut off the current path of the non-core digital load, and simultaneously outputs a high level signal to drive the controlled switch tube to be turned on, so that the transient charge of the auxiliary power supply bus is converted into heat energy by the dehumidification heating resistor; During the off state of the power switch unit, the hardware signal processing circuit obtains the feedback voltage rising slope of the second energy output port through the pre-close detection branch, and only when the feedback voltage rising slope exceeds the preset close preparation threshold value, the drive level of the power switch unit is restored.

2. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The system further includes a reference automatic calibration circuit; the reference automatic calibration circuit is used to extract a power frequency fundamental component in the first derivative induction signal, and correct the voltage gradient threshold value in the hardware signal processing circuit in proportion according to the amplitude variation of the power frequency fundamental component, so as to offset the induction impedance drift of the transient voltage gradient induction bridge.

3. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The transient voltage gradient induction bridge includes a first induction branch, a second induction branch and a differential operational amplifier circuit; the first induction branch is coupled to the primary side bus, and the second induction branch is coupled to the reference ground potential of the ring main unit; the input ends of the differential operational amplifier circuit are connected with the first induction branch and the second induction branch respectively, and are used to perform analog subtraction operation on the collected primary side power grid signal and the environmental common mode noise signal, so as to generate a first derivative induction signal with differential mode property.

4. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, characterized in that, The hardware signal processing circuit includes a self-resetting delay module composed of a resistor and a capacitor; The self-resetting delay module is connected to the output end of the window comparator, and is used to maintain the off state of the power switch unit until the preset physical cooling period ends after the first voltage rate of change level returns to below the voltage gradient threshold value.

5. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The positive and negative poles of the auxiliary power supply bus are connected in parallel with a support capacitor group, which is used to maintain the voltage stability of the first energy output port by using the stored charge during the off state of the power switch unit.

6. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The voltage gradient threshold is determined according to a discharge slope limit value of the auxiliary power bus The discharge slope limit value is set The discharge slope limit value satisfies the following calculation rule: Wherein, is an upper limit of the allowable voltage drop rate of the auxiliary power bus under a transient operating condition, is a preset total load current rating of the system, is a rated current value of the first energy output port, is an equivalent capacitance value of the support capacitor bank.

7. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The power switch unit is connected with an overcurrent locking link; the overcurrent locking link is used to forcibly block the drive level of the power switch unit when the real-time load current value of the second energy output port exceeds a preset overload limit value.

8. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The drive circuit of the controlled switch tube is connected with a charge fast discharge circuit, which is used to extract the gate charge of the controlled switch tube when the hardware signal processing circuit withdraws the driving high level.

9. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, The analog differentiator comprises an operational amplifier and a differential capacitor connected in the feedback loop of the operational amplifier, and through the charging and discharging characteristics of the differential capacitor, a first-order derivative induction signal is converted into a first-order voltage change rate level.

10. The intelligent power distribution circuit system for digitized ring main unit according to claim 1, wherein, According to the comparison result of the feedback voltage rising slope and the closing readiness threshold, the hardware signal processing circuit determines whether the charge storage state of the auxiliary power bus has the rigidity to support the non-core digital load inrush current.

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