Isolating lightning protection reactor

Abstract

The application discloses an isolated lightning protection reactor, and belongs to the technical field of lightning protection of electrical equipment. The isolated lightning protection reactor comprises a power supply side variable reactor, a grounding side variable reactor, a lightning detection circuit, an input side surge protector, an output side surge protector, a current sampling unit, a voltage sampling unit and a controller. The power supply side variable reactor is connected in series between a three-phase four-wire AC power input end and a base station switching power supply or a power consumption device, the input side surge protector, the power supply side variable reactor and the output side surge protector form a pi type discharge-isolation-discharge structure, and the lightning detection circuit is arranged on the line side of the input side surge protector. The grounding side variable reactor is connected in series in a direct current working ground or a grounding isolation branch. The controller controls the corresponding variable reactor to switch between a low inductance state and a high inductance state according to a lightning detection signal, a surge protector discharge current and a grounding voltage difference, so as to reduce normal loss and inhibit power supply side lightning surge and grounding side counterattack voltage.

Description

Technical Field

[0001] This invention belongs to the field of lightning protection technology for electrical equipment, specifically relating to an isolation lightning protection reactor for lightning surge isolation and suppression of power supply lines and grounding lines of communication base stations. In particular, it relates to an isolation lightning protection reactor that performs differentiated trigger control on the power supply side variable reactor and the grounding side variable reactor based on lightning detection signals, surge protector discharge current and grounding voltage difference, and switches the variable reactor between a low inductance state and a high inductance state through the separation, engagement or near engagement of C-type magnetic core and I-type magnetic core. Background Technology

[0002] Communication base stations, communication equipment rooms, and their supporting power supply equipment are typically located on rooftops, towers, mountains, open fields, and other areas susceptible to lightning activity. Base station equipment generally includes AC power distribution units, switching power supplies, battery banks, radio frequency remote units, baseband processing units, transmission equipment, and monitoring equipment. These devices are interconnected via power lines, signal lines, feeders, metal components, and grounding systems. When lightning strikes, on the one hand, the lightning current may be discharged to the ground through lightning arresters, down conductors, and grounding electrodes; on the other hand, the lightning electromagnetic pulse may also induce high common-mode or differential-mode surge voltages and surge currents on power lines, grounding lines, and metal components. If the surge energy enters the base station's internal equipment along the power lines or grounding lines, it can easily cause damage to the switching power supply, equipment port breakdown, communication interruption, data anomalies, or even permanent equipment failure.

[0003] Existing lightning protection systems for communication base stations typically employ surge protectors in conjunction with a grounding system. Surge protectors are usually connected in parallel between the protected line and the protective ground. When an overvoltage on the line reaches its operating condition, it conducts, discharging the surge current to the grounding system, thereby reducing the overvoltage experienced by downstream equipment. To improve the energy coordination between upstream and downstream surge protectors, existing technologies often incorporate decoupling inductors, decoupling resistors, or reactors between them. This ensures that the surge protectors operate in a predetermined sequence, and the reactors provide impedance suppression for the high-frequency components of lightning pulse currents.

[0004] For example, patent document CN210898528U discloses an isolated AC power distribution device. This device incorporates a power isolation suppressor, a ground isolation suppressor, a pre-stage discharge unit, a post-stage discharge unit, and a surge protector monitoring unit within a housing. This allows the pre-stage discharge unit, power isolation suppressor, and post-stage discharge unit to form an isolated lightning protection module, and utilizes the ground isolation suppressor to reduce the impact of lightning discharge on the working ground and protective ground. This type of solution adds a series isolation and suppression element to the surge discharge structure, thus improving lightning protection for base station power supply lines and grounding lines.

[0005] Patent document CN104617571A discloses an overvoltage and overcurrent protector for electronic and electrical equipment, which combines a power surge protector, a surge voltage divider composed of a reactor and a surge protector, and a power frequency current protector for combined protection. The reactor and surge protector work together to achieve surge residual voltage division protection. Patent document CN201821094U discloses a combined surge protector containing an LC decoupling element. This combined surge protector incorporates a decoupling inductor, a decoupling capacitor, and a working status recording device to improve lightning surge energy dissipation and status monitoring capabilities. Patent document CN207184045U discloses a distribution box suitable for strong lightning multi-pulse environments and used to prevent surge protectors from catching fire. It has a branch consisting of a backup protector and a surge protector on the power input side and a decoupling inductor on the outgoing side to reduce the risk of surge protector failure due to lightning current surges. The above scheme shows that the combined use of surge protectors with reactors or decoupling components has become a common technical means in the field of lightning protection.

[0006] To address the issue of ground potential backflash, patent document CN206226003U discloses a power line lightning protection and ground potential high-voltage backflash suppression protection device. This device connects a thermally protected metal oxide varistor module in parallel to the power line and a lightning current frequency impedance device in series on the grounding line to suppress the conduction of lightning surge voltage along the weak current grounding line after entering the combined grounding grid through the lightning protection grounding. Patent document CN204304426U discloses a backflash lightning protection device, which sets up a backflash lightning protection inductor, a backflash lightning protection resistor, and a parallel discharge gap between the tower and the lightning arrester to change the lightning discharge path and improve the backflash lightning protection capability. The above solutions mainly suppress ground potential backflash by increasing the grounding channel impedance or changing the discharge channel distribution relationship, but the impedance elements typically still use a fixed parameter structure.

[0007] On the other hand, the inductor or reactor body itself also has an adjustable structure. For example, patent document CN209266135U discloses an adjustable inductor, which adjusts the relative position of the magnetic core in the inner cavity of the cylindrical frame by means of a first magnetic core, a second magnetic core, a spring, and a clamping mechanism, thereby changing the inductance. This type of adjustable inductor can achieve inductance adjustment, but it is mainly used for installation and commissioning or matching of operating parameters. It usually does not use lightning surge conditions, surge protector discharge current, or ground voltage difference as the basis for automatic switching, nor does it establish separate trigger control mechanisms for lightning surges on the power supply side of the communication base station and ground potential backflash on the grounding side.

[0008] Therefore, although existing isolated lightning protection devices, reactor-type lightning protection devices, decoupled surge protectors, and ground potential backflash suppression devices can improve lightning protection capabilities to a certain extent, they still have the following shortcomings: First, existing power isolation suppressors, ground isolation suppressors, decoupling inductors, or lightning current frequency impedance devices mostly employ fixed inductance or fixed impedance structures. If the inductance or impedance value is increased to improve isolation and suppression capabilities under lightning strike conditions, this impedance element will remain connected in series in the power supply or grounding circuit for extended periods in non-lightning strike states, easily increasing power frequency voltage drop, harmonic excitation, core temperature rise, and operating losses. If the inductance or impedance value is decreased to reduce normal losses, it will be difficult to generate sufficient pulse impedance during lightning surges or ground backflash voltages. Therefore, fixed-parameter reactors cannot simultaneously meet the requirements of low insertion impedance during normal operation and high pulse impedance during lightning strikes.

[0009] Secondly, existing lightning protection devices typically treat power supply-side surge protection and grounding-side backflash suppression as relatively independent protection units, lacking differentiated judgment and control based on the power supply-side lightning surge state and the voltage difference between indoor and outdoor grounding points on the grounding side. In actual operation, induced lightning surges from power lines, ground potential backflashes caused by lightning arrester leakage, and combined lightning strikes occurring simultaneously have different locations, conduction paths, and damage mechanisms to equipment. If both the power supply and grounding sides use fixed reactors or the same triggering method, it is difficult to improve the isolation and suppression capabilities of the corresponding channels as needed according to different lightning strike conditions.

[0010] Third, while existing adjustable inductors can change their inductance by altering the core position or magnetic circuit state, they typically do not use lightning detection signals, surge protector discharge current, or ground voltage difference as the basis for automatic switching. Furthermore, they do not integrate the variable magnetic circuit structure with the three-phase four-wire power input / output structure, surge discharge structure, and ground backflash suppression structure. Therefore, when directly applying general adjustable inductors to lightning protection for communication base stations, it remains difficult to achieve the lightning protection control process of maintaining low inductance during normal operation, switching to high inductance during a lightning strike, and automatically restoring low inductance after the lightning strike ends.

[0011] Fourth, existing lightning protection devices typically rely on the leakage current after the surge protector is turned on or the operating status of the surge protector for lightning strike detection. For mechanical variable reactors that change inductance by moving a movable magnetic core via an electromagnetic drive coil, both the establishment of the drive coil current and the movement of the magnetic core require a certain response time. If the variable reactor is activated only after the surge protector has already turned on and generated a large leakage current, the reactor may not have completed the high inductance switching before the lightning surge front has already been conducted to downstream equipment. Current technology lacks a coordinated control mechanism to pre-trigger the power supply-side variable reactor before the surge protector turns on, based on the amplitude or rate of rise of the transient voltage of the input line, and to confirm the lightning event and maintain the high inductance state after the surge protector generates a leakage current. Summary of the Invention

[0012] To address the aforementioned issues, this invention provides an isolation lightning protection reactor designed to maintain both the power supply-side and grounding-side variable reactors in a low inductance and low insertion impedance state during normal operation, thereby reducing the impact on the base station power supply lines and grounding isolation branches. When the amplitude or rate of rise of the transient voltage on the input line meets the pre-triggering condition, the lightning detection circuit proactively drives the power supply-side variable reactor to switch to a high inductance state. After the surge protector generates a discharge current, the power supply-side lightning strike event is confirmed, and the high inductance state is maintained. When the grounding voltage difference between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body is detected to meet the backflash triggering condition, the grounding-side variable reactor is driven to switch to a high inductance and high pulse impedance state, thereby suppressing lightning surges conducted along the power supply line and ground potential backflashes conducted in the reverse direction along the grounding path, respectively. This achieves pre-triggering, event confirmation, and maintenance control of lightning surges on the power supply side, as well as independent judgment and suppression of grounding-side backflash voltage, improving the response speed, adaptability, safety, and reliability of lightning protection for communication base stations.

[0013] The technical solution adopted in this invention is as follows: An isolation lightning protection reactor includes a power supply side variable reactor, a grounding side variable reactor, a lightning detection circuit, an input side surge protector, an output side surge protector, a current sampling unit, a voltage sampling unit, and a controller. The power supply side variable reactor is connected in series between the three-phase four-wire AC power input terminal and the AC input terminal of the base station switching power supply or electrical equipment. The three-phase four-wire AC power input terminal includes phase A, phase B, phase C and N. The power supply side variable reactor includes four reactor units, and each phase and N line is connected in series with one reactor unit. The input-side surge protector is connected in parallel to the input side of the power supply-side variable reactor, and the output-side surge protector is connected in parallel to the output side of the power supply-side variable reactor. One end of the input-side surge protector and the output-side surge protector are respectively connected to the corresponding phase line or neutral line, and the other end is connected to the base station protection ground, so that the input-side surge protector, the power supply-side variable reactor, and the output-side surge protector together form a π-type discharge-isolation-discharge structure. The lightning detection circuit is installed on the line side of the surge protector on the input side. The voltage sampling terminal of the lightning detection circuit is connected to the AC power line on the input side of the variable reactor on the power supply side. The detection signal output terminal of the lightning detection circuit is connected to the controller. The lightning detection circuit is used to collect the transient voltage of the AC power line and output the lightning detection signal to the controller. The current sampling unit is installed on the grounding wire of at least one of the input-side surge protectors and the output-side surge protectors. The current sampling unit is connected to the controller and is used to collect the leakage current of the corresponding surge protector. The grounding-side variable reactor is connected in series in the working ground branch between the DC48V working ground terminal of the base station switching power supply and the DC working ground bus of the base station, or in series in the grounding isolation branch between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body; the two potential sampling terminals of the voltage sampling unit are respectively connected to the two ends of the grounding-side variable reactor, or respectively connected to the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body. The voltage sampling unit is connected to the controller and is used to collect the grounding voltage difference. Both the power supply-side variable reactor and the grounding-side variable reactor include an I-type magnetic core, a C-type magnetic core, a main reactor coil, a C-type magnetic core fixing block, a magnetic core separation spring, and a magnetic core attraction drive coil. The main reactor coil is wound on the corresponding magnetic post of the I-type magnetic core, or sleeved in the magnetic circuit window formed by the combination of the I-type magnetic core and the C-type magnetic core. The C-type magnetic core and the I-type magnetic core can switch between a separated position and an attracted or near-attracted position. When the controller does not output DC drive current to the corresponding magnetic core attraction drive coil, the magnetic core separation spring keeps the C-type magnetic core and the I-type magnetic core separated, so that the corresponding variable reactor is in a low inductance state. When the lightning detection signal meets the pre-triggering condition, or when the leakage current or leakage current change rate meets the power supply side event triggering condition, the controller outputs DC drive current to the magnetic core attraction drive coil of the power supply side variable reactor, so that the power supply side variable reactor switches to the high inductance state. When the ground voltage difference reaches the backflash voltage trigger threshold, or when the ground voltage difference undergoes a polarity reversal and the direction after the reversal is from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground, the controller outputs a DC drive current to the magnetic core attraction drive coil of the grounding side variable reactor, causing the grounding side variable reactor to switch to a high inductance state. Among them, the power supply-side variable reactor and the grounding-side variable reactor switch independently according to their respective triggering conditions.

[0014] Furthermore, the four reactor units of the power supply-side variable reactor correspond to the A-phase line, B-phase line, C-phase line and N-phase line respectively. Each reactor unit includes a main reactor coil, an I-type magnetic core and a C-type magnetic core. The four main reactor coils are electrically independent of each other. The four C-type magnetic cores are fixed side by side on the same C-type magnetic core fixing iron block and can synchronously approach or move away from the corresponding I-type magnetic core under the drive of the same magnetic core attraction drive coil.

[0015] Furthermore, the lightning detection circuit includes a voltage sampling terminal, a detection unit, and a detection signal output terminal. The detection unit is used to detect the transient voltage of the AC power line and output a lightning detection signal characterizing the transient voltage amplitude or rate of rise. The controller determines whether the lightning detection signal meets the pre-triggering condition based on any of the following conditions: or: ; in, for Lightning detection signal at any given moment; This is the lightning detection signal from the previous sampling time; Sampling time; The time interval between two adjacent samples; This is the pre-trigger threshold for the lightning detection signal; This is the pre-trigger threshold for the rise rate of the lightning detector signal; When any of the above conditions are met, the controller will drive the power supply-side variable reactor to switch from a low inductance state to a high inductance state in advance.

[0016] Furthermore, the current sampling unit is a Hall current sensor, a Rogowski coil, a current transformer, or a shunt resistor; The controller determines whether the power supply side lightning strike event trigger condition is met based on any of the following conditions: or: ; in, for The leakage current on the grounding conductor of the surge protector at all times; This represents the discharge current at the previous sampling time. Sampling time; The time interval between two adjacent samples; The threshold for triggering the discharge current; The trigger threshold is the rate of change of the discharge current; When any of the above conditions are met, the controller drives the power supply-side variable reactor to switch from a low inductance state to a high inductance state; when the power supply-side variable reactor has already entered the high inductance state by the lightning detection signal, the controller maintains the power supply-side variable reactor in the high inductance state.

[0017] Furthermore, the voltage sampling unit includes an indoor potential sampling terminal, an outdoor potential sampling terminal, a voltage divider circuit, an isolation conditioning circuit, and a filter circuit. The indoor potential sampling terminal is connected to the indoor protective ground or DC working ground, and the outdoor potential sampling terminal is connected to the outdoor grounding terminal or lightning protection grounding body. The controller calculates the ground voltage difference according to the following relationship: ; in, for The ground voltage difference at any given moment; For sampling time or time variables; for The potential of the outdoor grounding terminal or lightning protection grounding body at all times; for The potential of the indoor protective ground or DC working ground at all times; When the following conditions are met: Or it satisfies: and: When the controller determines that there is a backflash voltage conducted from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground, it drives the grounding side variable reactor to switch from a low inductance state to a high inductance state. in, This represents the ground voltage difference at the previous sampling time; The counter-attack voltage trigger threshold; This represents the time interval between two adjacent samples.

[0018] Furthermore, the inductance in the low inductance state is The inductance in the high inductance state is Both conditions are met: ; in, The inductance of the power supply-side variable reactor, the grounding-side variable reactor, or the reactor unit in a low inductance state; The inductance of the power supply-side variable reactor, the grounding-side variable reactor, or the reactor unit in a high inductance state; To increase the inductance factor, and Not less than 5.

[0019] Furthermore, the inductive reactance of the power supply-side variable reactor or the grounding-side variable reactor at the corresponding frequency satisfies: ; in, For the corresponding frequency The lower resistance; The frequency is the current frequency. This represents the inductance in the corresponding state. AC power frequency Under these conditions, the low inductance state satisfies: ; At the equivalent frequency of lightning pulse Under these conditions, the high inductance state satisfies: ; in, The AC power supply frequency; This is the equivalent frequency of the lightning pulse current or the equivalent frequency corresponding to the rising edge of the lightning pulse. To allow for the upper limit of normal insertion impedance; The lower limit of the pulse impedance required for lightning surge suppression; At power frequency under low inductance conditions The calculated inductive reactance; For high inductance conditions, based on the equivalent frequency of the lightning pulse The calculated inductive impedance.

[0020] Furthermore, the C-shaped magnetic core fixing block moves relative to the I-shaped magnetic core via a guiding mechanism, and the electromagnetic attraction force generated by the magnetic core attracting the drive coil satisfies: ; in, The electromagnetic attraction force generated by the magnetic core attracting the drive coil; The spring reaction force of the magnetic core separation spring; The guiding frictional resistance generated when the iron block fixing the C-type magnetic core moves along the guiding mechanism; Additional resistance is provided to account for vibration resistance requirements and safety margins; The spring reaction force of the magnetic core separation spring satisfies: ; in, For spring stiffness; The compression of the magnetic core release spring relative to its natural length or preload position; This is the preload force of the magnetic core separation spring.

[0021] Furthermore, the C-type magnetic core and the I-type magnetic core retain a non-magnetic limiting air gap in the high inductance state, and the non-magnetic limiting air gap is 0.1mm to 2mm; The core saturation check of the variable reactor on the power supply side or the variable reactor on the ground side meets the following requirements: ; in, Maximum operating magnetic flux density; The saturation magnetic flux density of the magnetic core material; A safety factor of 0.6 to 0.9; To allow the maximum magnetic flux density.

[0022] Furthermore, after the variable reactor on the power supply side or the variable reactor on the ground side enters the high inductance state, the controller determines the high inductance holding time according to the following relationship: ; in, For high inductance holding time; Based on the retention time; To maintain the number of times a lightning detection pre-trigger event, a power supply side lightning surge event, or a grounding side backflash event is detected again during the period; The duration to be maintained after each repeated triggering; When the variable reactor on the power supply side is in a high inductance state, the following conditions must be met: and: And continuously reset confirmation time When this happens, the controller cuts off the DC drive current of the magnetic core of the variable reactor on the power supply side to attract the drive coil; When the variable reactor on the ground side is in a high inductance state, the following conditions must be met: And continuously reset confirmation time At this time, the controller cuts off the DC drive current of the magnetic core of the variable reactor on the grounding side to attract the drive coil; After the DC drive current of the magnetic core attraction drive coil is cut off, the magnetic core separation spring drives the C-type magnetic core to separate from the I-type magnetic core, so that the corresponding variable reactor returns to the low inductance state. in, for Lightning detection signal at any given moment; The lightning detector signal reset threshold; for The leakage current on the grounding conductor of the surge protector at all times; The bleed current reset threshold; for The ground voltage difference at any given moment; The ground voltage difference reset threshold; This is the reset confirmation time.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention utilizes variable reactors on both the power supply and grounding sides, and alters the magnetic circuit state by changing the relative position of a C-type core and an I-type core, enabling the variable reactor to switch between low and high inductance states. Under normal operating conditions, the C-type and I-type cores remain separated, resulting in lower inductance and insertion impedance for the variable reactor, which helps reduce power frequency voltage drop, core temperature rise, and long-term operating losses. Under lightning surge or ground fault conditions, the controller drives the C-type core closer to the I-type core, causing the variable reactor to form a low-resistivity magnetic circuit and enter a high-inductance state. This improves the ability to impede high-frequency components and fast-rising-edge currents from lightning pulses, solving the problem that fixed-parameter reactors struggle to balance low losses under normal conditions with high pulse impedance under lightning strikes.

[0024] 2. This invention incorporates a lightning detection circuit on the line side of the input-side surge protector. It collects the transient voltage of the input line and extracts its amplitude or rate of rise to form a lightning detection signal. When the lightning detection signal meets the pre-triggering condition, the controller can initiate the high-inductance switching process of the power supply-side variable reactor in advance. After the input-side or output-side surge protector generates a leakage current, the controller confirms the lightning strike event on the power supply side and maintains the high-inductance state based on the leakage current or its rate of change. This forms a coordinated control method of "lightning detection pre-triggering - SPD leakage event confirmation - high-inductance state maintenance," which helps reduce the response lag caused by only initiating the mechanical core action after the SPD is turned on.

[0025] 3. This invention includes an input-side surge protector and an output-side surge protector on the input and output sides of the power supply-side variable reactor, respectively, forming a π-type discharge-isolation-discharge structure. The input-side surge protector prioritizes the discharge of the main lightning current, the power supply-side variable reactor, in a high-inductance state, suppresses the residual surge from propagating to subsequent stages, and the output-side surge protector performs secondary discharge of the residual surge after passing through the power supply-side variable reactor, thereby improving the graded protection capability for base station switching power supplies, communication main equipment, and other electrical equipment.

[0026] 4. This invention installs a grounding-side variable reactor in the grounding isolation branch between the base station DC working ground bus, or the indoor protective ground or DC working ground, and the outdoor grounding terminal or lightning protection grounding body. A voltage sampling unit collects the grounding voltage difference between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body. The controller determines whether a backflash voltage exists, conducted from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground, based on the amplitude, polarity, or polarity reversal state of the grounding voltage difference. When the triggering condition is met, the grounding-side variable reactor is driven into a high-inductance state, thereby reducing the risk of ground potential rise and backflash voltage entering the indoor communication equipment along the grounding path.

[0027] 5. This invention employs differentiated trigger control for the power supply-side and grounding-side variable reactors. On the power supply side, the judgment criteria are lightning detection signals, surge protector discharge current, or discharge current change rate; on the grounding side, the judgment criteria are the amplitude of the ground voltage difference, polarity reversal state, or backflash direction. Therefore, the controller can control the corresponding variable reactors to switch states for different lightning strike conditions, including induced lightning surges on the power line, grounding potential backflash, and combined lightning strikes occurring simultaneously. This avoids malfunctions or insufficient protection caused by using the same trigger conditions for different conduction paths, and improves the adaptability of the isolation lightning protection reactor to different lightning strike conditions.

[0028] 6. This invention forms a mechanical variable magnetic circuit structure through a C-type magnetic core, an I-type magnetic core, a C-type magnetic core fixing block, a magnetic core separation spring, a magnetic core attraction drive coil, and a guiding mechanism. Multiple C-type magnetic cores can be fixed to the same C-type magnetic core fixing block and synchronously move closer to or further away from their corresponding I-type magnetic cores under the action of the same magnetic core attraction drive coil, thereby enabling multiple reactor units in a three-phase four-wire system to synchronously switch inductance. The magnetic core separation spring can push the C-type magnetic core to reset after the drive current is cut off, allowing the reactor to automatically return to a low inductance state. This structure facilitates repeated switching between high and low inductance states and automatic reset.

[0029] 7. This invention maintains a high inductance state for the variable reactor during multi-pulse or continuous backflash lightning events by setting up a high inductance state maintenance, repeated trigger delay, and reset confirmation mechanism. When the lightning detection signal, surge protector discharge current, or ground voltage difference falls below the corresponding reset threshold and remains below it for a preset time, the controller then cuts off the DC drive current of the corresponding magnetic core engaging drive coil. This reduces the frequent engaging and disengaging of the variable reactor in critical states, improving control stability and continuous protection against multi-pulse lightning strikes.

[0030] 8. This invention modularizes the three-phase four-wire input terminal, three-phase four-wire output terminal, lightning detection circuit, surge protector, current sampling unit, voltage sampling unit, controller, movable magnetic core, magnetic core separation spring, and magnetic core attraction drive coil, enabling it to be connected as a multi-port lightning protection electrical device to the power supply line and grounding isolation branch of the communication base station. This facilitates the installation, modification, and engineering deployment in existing communication base station lightning protection systems.

[0031] In summary, this invention, through the coordinated operation of lightning detection pre-triggering, surge protector leakage event confirmation, power supply side π-type discharge-isolation-discharge, grounding side backflash voltage sampling, variable magnetic circuit high and low inductance switching, and differentiated control between the power supply side and the grounding side, can reduce insertion impedance and operating losses during normal operation, and improve the isolation and suppression capabilities against power supply side lightning surges and grounding side backflash voltages under lightning strike conditions. This improves the response speed, stability, safety, reliability, and adaptability of lightning protection for communication base stations. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments are briefly described below. It should be understood that the following drawings only show some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings.

[0033] Figure 1 This is a schematic diagram of the overall connection structure of the isolation lightning protection reactor in an embodiment of the present invention; Figure 2This is a schematic diagram of the lightning detection circuit and the power supply side π-type discharge-isolation-discharge structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the grounding-side backflash suppression unit and voltage sampling structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the internal overall structure of the variable impedance lightning protection reactor in an embodiment of the present invention; Figure 5 This is a schematic diagram of the internal partial structure of the variable impedance lightning protection reactor in an embodiment of the present invention; Figure 6 This is a schematic diagram of the external terminal layout of a variable impedance lightning protection reactor in an embodiment of the present invention; Figure 7 This is a schematic diagram of the terminal and guide mechanism layout of the variable impedance lightning protection reactor in an embodiment of the present invention; Figure 8 This is a schematic diagram of the core separation structure of the variable impedance lightning protection reactor in a low inductance state in an embodiment of the present invention. Figure 9 This is a schematic diagram of the magnetic core near-closing structure when the variable impedance lightning protection reactor is in a high inductance state in an embodiment of the present invention. Figure 10 This is a block diagram of the functional modules of the controller and its lightning detection, current sampling, and voltage sampling inputs in an embodiment of the present invention. Figure 11 This is a schematic diagram of the pre-triggering, event confirmation, holding, and reset control process of the isolation lightning protection reactor in this embodiment of the invention; In the diagram: 100, power supply side variable reactor; 200, grounding side variable reactor; 300, current sampling unit; 400, voltage sampling unit; 500, controller; 610, input side surge protector; 620, output side surge protector; 700, lightning detection circuit; 10. Housing; 20. Coil assembly; 30. Type I magnetic core; 40. Type C magnetic core; 50. Type C magnetic core fixing block; 60. Magnetic core separation spring; 70. Magnetic core attraction drive coil; 80. Guide mechanism; 90. Input terminal; 91. Output terminal; 92. Drive terminal; A, A-phase line; B, B-phase line; C, C-phase line; N, N-line; PE, base station protective ground; G1, indoor protective ground or DC working ground; G2, outdoor grounding terminal or lightning protection grounding body; First air gap; Second air gap. Detailed Implementation

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Any substitutions made by those skilled in the art regarding the quantity, materials, installation direction, connection method, control parameters, and equivalent structures of the components without departing from the concept of the present invention should fall within the scope of protection of the present invention.

[0035] This embodiment provides an isolation lightning protection reactor, such as Figures 1 to 11 As shown, this isolation lightning protection reactor is used in communication base stations, communication equipment rooms, distribution boxes, the input side of switching power supplies, and ground backflash suppression lines. It can control the power supply-side variable reactor 100 and the grounding-side variable reactor 200 to switch between low inductance and high inductance states according to the lightning detection signal, the surge protector discharge state, and the grounding-side backflash voltage state. This reduces the insertion impedance and operating loss under normal operating conditions, and increases the pulse impedance under lightning surge or ground potential backflash conditions, suppressing the conduction of lightning surge current or backflash voltage to downstream communication equipment.

[0036] For ease of explanation, in this embodiment, the variable impedance device installed on the AC power input side is referred to as the power supply-side variable reactor 100, and the variable impedance device installed on the grounding side is referred to as the grounding-side variable reactor 200. Both the power supply-side variable reactor 100 and the grounding-side variable reactor 200 can adopt the variable impedance lightning protection reactor structure of this embodiment.

[0037] The overall composition and connection method of this isolation lightning protection reactor are as follows: like Figure 1 As shown, the isolation surge protector provided in this embodiment is not a single fixed inductor coil, but a multi-port surge protection electrical device that integrates lightning detection, surge discharge, variable reactance isolation, state sampling, and drive control functions. This isolation surge protector includes a power supply-side variable reactor 100, a grounding-side variable reactor 200, a current sampling unit 300, a voltage sampling unit 400, a controller 500, an input-side surge protector 610, an output-side surge protector 620, and a lightning detection circuit 700.

[0038] like Figure 1 and Figure 2 As shown, the power supply-side isolation surge protection unit includes a power supply-side variable reactor 100, an input-side surge protector 610, an output-side surge protector 620, and a lightning detection circuit 700. The power supply-side variable reactor 100 is connected in series between the AC 380V three-phase four-wire AC power input terminal and the AC input terminal of the base station switching power supply or other electrical equipment. The three-phase four-wire AC power input terminal includes phase A, phase B, phase C, and neutral (N) lines. The power supply-side variable reactor 100 includes four reactor units, with one reactor unit connected in series for each phase line and the neutral (N) line.

[0039] The input-side surge protector 610 is connected in parallel to the input side of the power supply-side variable reactor 100, and the output-side surge protector 620 is connected in parallel to the output side of the power supply-side variable reactor 100. One end of the input-side surge protector 610 and the output-side surge protector 620 are respectively connected to the corresponding phase line or neutral line, and the other end is connected to the base station protective ground PE. Thus, the input-side surge protector 610, the power supply-side variable reactor 100, and the output-side surge protector 620 together constitute a π-type discharge-isolation-discharge structure of front-stage discharge-variable reactor isolation-rear-stage discharge.

[0040] The lightning detection circuit 700 is located on the line side of the input surge protector 610. Its voltage sampling terminal is connected to the AC power line on the input side of the power supply variable reactor 100, and its detection signal output terminal is connected to the controller 500. The lightning detection circuit 700 is used to acquire transient voltages on the AC power line and outputs a lightning detection signal representing the amplitude or rising trend of the transient voltage to the controller 500.

[0041] It should be noted that the lightning detection circuit 700 is a detection branch and not part of the main energy conduction channel of the π-type discharge-isolation-discharge structure. The π-type structure is still composed of the input-side surge protector 610, the power-side variable reactor 100, and the output-side surge protector 620.

[0042] like Figure 1 and Figure 3 As shown, the grounding-side backflash suppression unit includes a grounding-side variable reactor 200 and a voltage sampling unit 400. The grounding-side variable reactor 200 is connected in series in the working ground branch between the DC48V working ground terminal of the base station switching power supply and the base station DC working ground bus, or in series in the grounding isolation branch between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding electrode. This grounding isolation branch is used to suppress the backflash voltage conducted from the outdoor grounding terminal or lightning protection grounding electrode to the indoor protective ground or DC working ground when lightning discharge occurs at the outdoor grounding terminal or lightning protection grounding electrode and causes a ground potential rise.

[0043] For paths where maintaining low impedance continuity of protective grounding is essential, the grounding-side variable reactor 200 should not disrupt the safety continuity of protective grounding. In actual installation, a power frequency or DC low impedance bypass, equipotential bonding branch, or safety protection connection structure can be installed on the main protective grounding channel to ensure that the protective grounding function does not fail due to the grounding-side variable reactor 200 entering a high inductance state. The grounding-side variable reactor 200 should be installed in a grounding isolation branch or a DC working ground backflash suppression branch that does not affect the continuity of protective grounding.

[0044] The composition and pre-triggering principle of the lightning detection circuit are as follows: like Figure 2 and Figure 10 As shown, the lightning detection circuit 700 may include a voltage sampling branch, a limiting protection branch, a detection branch, a filtering branch, an isolation output branch, and a detection signal output terminal.

[0045] The voltage sampling branch is connected to the AC power input line to obtain the sampling voltage corresponding to the transient voltage of the AC power line. The limiting protection branch limits the voltage amplitude entering the subsequent detection branch to prevent damage to the detection elements from lightning surges. The detection branch extracts the amplitude, envelope, or rising trend of the sampling voltage. The filtering branch suppresses normal power frequency fluctuations and high-frequency interference. The isolation output branch provides electrical isolation between the AC high-voltage line and the controller 500, and outputs a lightning detection signal to the controller 500.

[0046] The lightning detection circuit 700 can sample phase A, phase B, and phase C lines separately, or it can sample multiple AC input lines through multiplexing. When the lightning detection signal output from any sampling channel meets the pre-trigger condition, the controller 500 can drive the power supply-side variable reactor 100 into a high-inductance state in advance.

[0047] In this embodiment, the lightning detection signal output by the lightning detection circuit 700 is denoted as... The controller 500 can determine whether the pre-trigger condition is met based on any of the following conditions: or: ; in, for Lightning detection signal at any given moment; This is the lightning detection signal from the previous sampling time; Sampling time; The time interval between two adjacent samples; This is the pre-trigger threshold for the lightning detection signal; This is the pre-trigger threshold for the rise rate of the lightning detector signal.

[0048] The pre-trigger threshold can be determined based on the AC power supply rated voltage, the sampling ratio of the lightning detection circuit 700, the operating voltage of the input surge protector 610, the processing time of the controller 500, and the mechanical action time of the C-type magnetic core 40. The transient voltage of the line corresponding to the lightning detection signal pre-trigger threshold is lower than the operating voltage of the input surge protector 610, thereby enabling the controller 500 to initiate the state switching of the power supply-side variable reactor 100 before the input surge protector 610 is officially turned on.

[0049] In this embodiment, the lightning detection pre-trigger does not replace the surge discharge function of the input-side surge protector 610 and the output-side surge protector 620, but is used to initiate the magnetic core engaging action in advance. After the input-side surge protector 610 or the output-side surge protector 620 actually generates a leakage current, the controller 500 confirms the lightning strike event on the power supply side based on the leakage current or the leakage current change rate, and maintains the power supply-side variable reactor 100 in a high inductance state.

[0050] The installation location, connection relationship, and function of the variable reactor on the power supply side are as follows: like Figure 1 and Figure 2 As shown, the power supply-side variable reactor 100 is connected in series between the AC 380V three-phase four-wire power input terminal and the base station switching power supply or other electrical equipment. The power supply-side variable reactor 100 includes an A-phase reactor unit, a B-phase reactor unit, a C-phase reactor unit, and an N-line reactor unit. The A-phase reactor unit is connected in series in the A-phase line, the B-phase reactor unit is connected in series in the B-phase line, the C-phase reactor unit is connected in series in the C-phase line, and the N-line reactor unit is connected in series in the N-line.

[0051] The four reactor units are electrically independent and isolate and suppress surge currents in their respective conductors. By setting up four reactor units corresponding to three-phase four-wire systems, the risk of unintended electrical coupling or power frequency imbalance between the three-phase four-wire systems can be reduced, and each phase line and neutral line can have independent lightning pulse suppression capabilities.

[0052] The input-side surge protector 610 is located at the front end of the power supply-side variable reactor 100, and the output-side surge protector 620 is located at the rear end of the power supply-side variable reactor 100. The input-side surge protector 610 is used to preferentially discharge the main surge current from the AC power input side, and the output-side surge protector 620 is used to perform secondary discharge of the residual surge after passing through the power supply-side variable reactor 100.

[0053] Under normal power supply conditions, the lightning detection signal does not reach the pre-trigger condition, and no surge protector leakage current is detected. The power supply-side variable reactor 100 is in a low inductance state. At this time, the power supply-side variable reactor 100 only forms a low insertion impedance for power frequency current, and AC power can supply power to the base station switching power supply or other electrical equipment through the power supply-side variable reactor 100.

[0054] When the amplitude or rate of rise of the lightning detection signal meets the pre-triggering condition, the controller 500 outputs a DC drive current to the magnetic core attraction drive coil 70 of the variable reactor 100 on the power supply side, causing the C-type magnetic core 40 to move closer to the I-type magnetic core 30, thus initiating the switch from the low inductance state to the high inductance state in advance.

[0055] When the input-side surge protector 610 or the output-side surge protector 620 is turned on and generates a leakage current, the current sampling unit 300 detects the leakage current on the grounding wire of the surge protector and sends the leakage current signal to the controller 500. The controller 500 confirms the lightning strike event on the power supply side based on the leakage current amplitude or the leakage current change rate, and keeps the power supply-side variable reactor 100 in a high inductance state.

[0056] Under high inductance conditions, the main lightning current is discharged to the base station protective ground PE through the input-side surge protector 610. The residual surge is suppressed by the high pulse impedance of the power supply-side variable reactor 100 and then discharged again by the output-side surge protector 620, thereby reducing the risk of the residual surge continuing to be conducted to the downstream base station switching power supply, main equipment and other electrical equipment.

[0057] The installation location, connection relationship, and function of the grounding-side variable reactor are as follows: like Figure 1 and Figure 3 As shown, the grounding-side variable reactor 200 is connected in series with the base station DC working ground bus, the base station switching power supply DC48V working ground terminal, or the grounding isolation branch between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body.

[0058] The indoor potential sampling terminal of the voltage sampling unit 400 is connected to the indoor protective ground or DC working ground, and the outdoor potential sampling terminal is connected to the outdoor grounding terminal or lightning protection grounding body. The voltage sampling unit 400 samples and processes the potential of the indoor and outdoor grounding points through a voltage divider circuit, an isolation conditioning circuit, and a filter circuit, and outputs a grounding voltage difference signal to the controller 500.

[0059] The controller 500 calculates the ground voltage difference according to the following relationship: ; in, for The ground voltage difference at any given moment; for The potential of the outdoor grounding terminal or lightning protection grounding body at all times; for The potential of the indoor protective ground or DC working ground at all times.

[0060] when: or: and: When the controller 500 determines that there is a backflash voltage conducted from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground, it drives the grounding side variable reactor 200 to switch from a low inductance state to a high inductance state.

[0061] in, This represents the ground voltage difference at the previous sampling time. The counter-attack voltage trigger threshold, This represents the time interval between two adjacent samples.

[0062] When no grounding backflash voltage is detected, the grounding-side variable reactor 200 maintains a low inductance state to reduce the impact on the normal operation of the DC working ground and the grounding isolation branch. When a grounding backflash voltage is detected, the grounding-side variable reactor 200 enters a high inductance state, forming a higher impedance to high-frequency lightning pulses and reverse potential rise, thereby reducing the risk of backflash voltage entering indoor equipment in the reverse direction along the grounding path.

[0063] The structure of the variable impedance lightning protection reactor is as follows: like Figure 4 and Figure 5 As shown, both the power supply-side variable reactor 100 and the grounding-side variable reactor 200 can adopt a variable impedance lightning protection reactor structure. This variable impedance lightning protection reactor includes a housing 10, a coil assembly 20, an I-type magnetic core 30, a C-type magnetic core 40, a C-type magnetic core fixing block 50, a magnetic core separation spring 60, a magnetic core attraction drive coil 70, a guide mechanism 80, an input terminal 90, an output terminal 91, and a drive terminal 92.

[0064] The housing 10 can be an insulating housing or a metal housing with an internal insulating bushing, insulating partition, and insulating support. The housing 10 is used to house the coil assembly 20, the type I magnetic core 30, the type C magnetic core 40, the type C magnetic core fixing block 50, the magnetic core separation spring 60, and the magnetic core attraction drive coil 70, and provides a mounting base for each electrical terminal and the moving parts of the magnetic core.

[0065] like Figure 6 and Figure 7 As shown, an input terminal 90 is provided on one side of the housing 10, and an output terminal 91 is provided on the opposite side. A drive terminal 92 is provided on the end face of the housing 10. For the power supply side variable reactor 100, the input terminal 90 includes an A-phase input terminal, a B-phase input terminal, a C-phase input terminal, and a neutral (N) line input terminal; the output terminal 91 includes an A-phase output terminal, a B-phase output terminal, a C-phase output terminal, and a neutral (N) line output terminal. The drive terminal 92 is the DC power supply input terminal for the magnetic core engaging drive coil 70.

[0066] The coil assembly 20 includes four main reactor coils, which are connected in series in phase A, phase B, phase C, and neutral (N) lines, respectively. Each main reactor coil is wound on a magnetic post corresponding to a type I magnetic core 30, or fitted into a magnetic circuit window formed by the combination of a type I magnetic core 30 and a type C magnetic core 40. The four main reactor coils are electrically independent of each other and are isolated from each other by insulating partitions, insulating supports, or spaced arrangement structures.

[0067] like Figure 7 As shown, the type I magnetic core 30 is fixedly installed inside the housing 10, and the type C magnetic core 40 is movable relative to the type I magnetic core 30. Multiple type C magnetic cores 40 are arranged side by side along the length of the housing 10 and are fixedly connected to the same type C magnetic core fixing iron block 50, so that multiple type C magnetic cores 40 can move synchronously under the action of the same driving force.

[0068] Specifically, the C-shaped magnetic core fixing block 50 is slidably installed inside the housing 10 via the guide mechanism 80. In this embodiment, the guide mechanism 80 adopts a guide groove structure set on both sides inside the housing 10. The C-shaped magnetic core fixing block 50 is provided with a sliding engagement part that cooperates with the guide groove at the corresponding position, so that the C-shaped magnetic core fixing block 50 can reciprocate along a preset direction, thereby driving multiple C-shaped magnetic cores 40 to synchronously approach or move away from the corresponding I-shaped magnetic core 30. By setting the guide mechanism 80, the movement path of the C-shaped magnetic core fixing block 50 can be limited, avoiding the C-shaped magnetic core fixing block 50 from deviating, tilting or getting stuck during the movement, so that multiple C-shaped magnetic cores 40 and the corresponding I-shaped magnetic core 30 maintain a stable relative positional relationship, improving the reliability and repeatability of the magnetic core attraction process. In an alternative embodiment, the guide mechanism 80 is not limited to the above-mentioned guide groove structure, and can also adopt a guide rod and sliding sleeve cooperation structure, a slider and sliding rail cooperation structure, a limiting guide seat structure or other equivalent guide structures that can limit the movement direction of the C-shaped magnetic core fixing block 50.

[0069] The magnetic core separation spring 60 is disposed between the housing 10 and the C-shaped magnetic core fixing block 50, or between the C-shaped magnetic core fixing block 50 and the fixed support. When the magnetic core attraction drive coil 70 is not energized, the magnetic core separation spring 60 pushes the C-shaped magnetic core fixing block 50 to reset, so that the C-shaped magnetic core 40 is away from the I-shaped magnetic core 30.

[0070] When a DC drive current is applied to the magnetic core attraction drive coil 70, an electromagnetic attraction force is generated, which drives the C-type magnetic core fixing iron block 50 to move, causing the C-type magnetic core 40 to move closer to the I-type magnetic core 30 until the two are in an attracted or nearly attracted state.

[0071] like Figure 8 As shown, in the low inductance state, there is a first air gap between the C-type magnetic core 40 and the I-type magnetic core 30. .like Figure 9 As shown, in the high inductance state, there is a second air gap between the C-type magnetic core 40 and the I-type magnetic core 30. Second air gap Smaller than the first air gap .

[0072] First air gap The second air gap can be 1mm to 20mm. The second air gap can range from 0.1mm to 2mm. It can be formed from non-magnetic limiting components, ceramic limiting blocks, insulating gaskets, or impact-resistant limiting components, used to reduce the risk of core saturation and rigid impact while increasing inductance. The above-mentioned air gap values ​​should be determined based on the actual core size, the number of turns of the main reactance coil, the rated current, and the lightning surge level.

[0073] The design of high and low inductance, inductive reactance, and magnetic core drive is as follows: Combination Figure 8 and Figure 9 The magnetic core separation state and the magnetic core attraction or near attraction state shown in this embodiment are not described as "zero reactance" when no lightning strike occurs, but are defined as a low inductance state. In the low inductance state, a first air gap is maintained between the C-type magnetic core 40 and the I-type magnetic core 30. The magnetic reluctance of the magnetic circuit is relatively large, resulting in a low inductance of the main reactance coil; under the high inductance condition, the C-type magnetic core 40 moves closer to the I-type magnetic core 30, forming a gap between them smaller than the first air gap. Second air gap The magnetic reluctance of the magnetic circuit decreases, which increases the inductance of the main reactance coil.

[0074] Let the inductance in the low inductance state be The inductance in the high inductance state is Both conditions are met: ; in, The inductance of the corresponding power supply side variable reactor 100, ground side variable reactor 200, or one of the reactor units in the low inductance state; The inductance of the corresponding power supply side variable reactor 100, ground side variable reactor 200, or one of the reactor units in the high inductance state; To increase the inductance factor, and The value is no less than 5.

[0075] In one specific embodiment, low inductance It can be set from 1μH to 100μH, with high inductance. It can be set from 0.1mH to 10mH. The specific value can be determined based on the base station power supply capacity, AC line rated operating current, allowable power frequency voltage drop, surge protector protection level, main reactor coil turns, core material, effective core cross-sectional area, and first air gap. Second air gap And parameters such as allowable insertion impedance are determined.

[0076] The inductive reactance of the variable reactor at the corresponding frequency satisfies: ; in, For the corresponding frequency The lower resistance; The frequency of the current flowing through the main reactor coil; This represents the inductance in the corresponding state.

[0077] AC power frequency Under these conditions, the low inductance state satisfies: ; in, The AC power supply frequency; To allow for the upper limit of normal insertion impedance; At power frequency under low inductance conditions The calculated inductive reactance. By making... Exceeding the upper limit of the allowable normal insertion impedance can reduce the line voltage drop, operating loss and core temperature rise caused by the power supply-side variable reactor 100 under normal power supply conditions.

[0078] At the equivalent frequency of lightning pulse Under these conditions, the high inductance state satisfies: ; in, It is the equivalent frequency of the lightning pulse current, or the equivalent frequency corresponding to the rising edge of the lightning pulse; The lower limit of the pulse impedance required to suppress lightning surges; For high inductance conditions, based on the equivalent frequency of the lightning pulse The calculated inductive reactance. By making... A pulse impedance not lower than the required lower limit allows the variable reactor to form a higher impedance to the high-frequency components of the lightning pulse and the fast-rising-edge current under lightning surge conditions.

[0079] Therefore, this embodiment can maintain a low power frequency insertion impedance of the variable reactor under normal power supply conditions, reducing the impact on the normal operation of the base station power supply system; under lightning surge or ground backflash conditions, it enables the corresponding variable reactor to obtain a higher lightning pulse equivalent inductive reactance, improving the isolation and suppression capability against lightning surge and backflash voltage.

[0080] The core drive and reset design is as follows: like Figure 4 , Figure 5 , Figure 8 and Figure 9As shown, the magnetic core engagement drive coil 70 is powered by the controller 500 through the drive output module and the drive coil power supply module. The drive voltage of the magnetic core engagement drive coil 70 can be DC12V, DC24V, or DC48V. In one specific embodiment, the magnetic core engagement drive coil 70 uses a DC48V DC drive voltage to match the DC power supply system or control power supply of the communication base station.

[0081] When the lightning detection signal meets the pre-triggering condition, the surge protector discharge current meets the power supply side event triggering condition, or the ground voltage difference meets the grounding side backflash triggering condition, the controller 500 outputs a DC drive current to the magnetic core attraction drive coil 70 of the corresponding variable reactor. The magnetic core attraction drive coil 70 generates an electromagnetic attraction force after being energized. Electromagnetic attraction force satisfy: ; in, The electromagnetic attraction force generated by the magnetic core attraction drive coil 70; The spring reaction force of the magnetic core separation spring 60; The guiding frictional resistance of the C-type magnetic core fixing iron block 50 during its movement along the guide mechanism 80; Additional resistance is set to take into account vibration resistance requirements, safety margins, and other additional resistances.

[0082] The spring reaction force of the magnetic core separation spring 60 satisfies: ; in, The spring stiffness of the magnetic core separation spring 60; The amount of compression of the magnetic core separation spring 60 relative to its natural length or preloaded position; This is the preload force of the magnetic core separation spring 60.

[0083] When electromagnetic attraction force When the sum of the spring reaction force of the magnetic core separation spring 60, the guiding friction resistance, and the additional resistance is greater than or equal to the sum of the magnetic core attraction drive coil 70, the magnetic core attraction drive coil 70 can drive the C-type magnetic core fixing iron block 50 to move along the guide mechanism 80, and drive multiple C-type magnetic cores 40 to move synchronously towards the corresponding I-type magnetic core 30, so that the air gap between the C-type magnetic core 40 and the I-type magnetic core 30 is reduced from the first air gap. Reduced to the second air gap This allows the corresponding variable reactor to switch from a low inductance state to a high inductance state.

[0084] For the power supply-side variable reactor 100, when the lightning detection signal output by the lightning detection circuit 700 meets the pre-triggering condition, the controller 500 outputs a DC drive current to the magnetic core engaging drive coil 70 in advance to start the movement process of the C-type magnetic core 40 ahead of time. The pre-triggering threshold of the lightning detection signal should be set in combination with the detection delay of the lightning detection circuit 700, the processing delay of the controller 500, the current settling time of the magnetic core engaging drive coil 70, and the mechanical movement time of the C-type magnetic core 40, in order to reduce the action lag caused by only starting to drive the magnetic core after the surge protector generates a discharge current.

[0085] When the input-side surge protector 610 or the output-side surge protector 620 generates a leakage current that meets the triggering conditions, the controller 500 confirms the lightning strike event on the power supply side and continues to keep the magnetic core engaging drive coil 70 energized, so that the power supply-side variable reactor 100 remains in a high inductance state.

[0086] When a lightning strike or grounding backflash event ends, and the corresponding detection signal is below the reset threshold for a preset reset confirmation time, the controller 500 cuts off the DC drive current of the corresponding magnetic core attraction drive coil 70. After the electromagnetic attraction force of the magnetic core attraction drive coil 70 disappears, the magnetic core separation spring 60 pushes the C-type magnetic core fixing block 50 to move in the opposite direction, causing the C-type magnetic core 40 to move away from the I-type magnetic core 30, restoring the first air gap. The corresponding variable reactor returns from a high inductance state to a low inductance state.

[0087] By setting the core separation spring 60, the C-type magnetic core 40 can be automatically reset when the magnetic core attraction drive coil 70 is de-energized, preventing the variable reactor from remaining in a high inductance state for a long time. At the same time, the core separation spring 60 can also apply a preload to the C-type magnetic core fixing block 50, reducing the risk of the C-type magnetic core 40 shaking, colliding, or drifting in the vibration environment of the communication base station.

[0088] The anti-saturation design is as follows: To avoid core saturation caused by residual surge current, multi-pulse lightning current, or continuous counter-pulse under high inductance conditions, this embodiment can adopt at least one of the following anti-saturation measures.

[0089] First, an input-side surge protector 610 is installed on the input side of the power supply-side variable reactor 100, so that the main lightning current is preferentially discharged to the base station protection ground PE through the input-side surge protector 610. The power supply-side variable reactor 100 is mainly used to suppress the residual high-frequency pulse and subsequent pulse energy after the previous stage discharge, rather than acting as the main discharge element to bear all the lightning current, thereby reducing the peak current and magnetic flux density borne by the main reactor coil and magnetic core.

[0090] Second, such as Figure 9As shown, the C-type magnetic core 40 and the I-type magnetic core 30 retain the second air gap under high inductance conditions. Second air gap It is formed by a non-magnetic limiting component, which can be a ceramic limiting block, an insulating gasket, a non-magnetic metal limiting plate, or an impact-resistant limiting component. A second air gap is retained. It can increase the equivalent magnetic reluctance of the magnetic circuit, reduce the risk of the magnetic core entering a deep saturation state under the action of a large pulse current, and avoid direct rigid collision between the C-type magnetic core 40 and the I-type magnetic core 30.

[0091] Third, the Type I magnetic core 30 and the Type C magnetic core 40 employ magnetic materials with high saturation magnetic flux density. These magnetic materials can be silicon steel sheets, ferrite, amorphous alloys, nanocrystalline materials, or composite core structures composed of different magnetic materials. The core material should be selected based on the AC power frequency operating conditions, the lightning pulse frequency range, core loss, saturation magnetic flux density, and mechanical strength.

[0092] Fourth, the main reactor coil can adopt segmented windings, multi-column parallel magnetic circuits, multi-core current-sharing structures, or multiple reactor units connected in parallel to share the magnetic flux, in order to reduce the magnetic flux density borne by a single magnetic circuit. For the three-phase four-wire power supply side variable reactor 100, the A-phase reactor unit, B-phase reactor unit, C-phase reactor unit, and N-line reactor unit can each adopt independent magnetic circuits, so that the surge current in different lines is borne by the corresponding magnetic circuit, reducing the mutual influence between magnetic circuits.

[0093] Fifth, the operating status of the magnetic core can be monitored based on the drive coil current, main reactor coil current, core position, or high inductance holding time. When the main reactor coil current, core temperature rise, or high inductance holding time exceeds a preset limit, the controller 500 can output an alarm message or adjust the driving mode of the magnetic core engaging drive coil 70 to reduce the risk of the magnetic core being continuously in a high flux density state.

[0094] Core saturation check satisfies: ; in, Maximum operating magnetic flux density; The saturation magnetic flux density of the magnetic core material; A safety factor less than 1; To determine the maximum permissible magnetic flux density, a safety factor of 0.6 to 0.9 is used.

[0095] Maximum operating magnetic flux density Based on the effective cross-sectional area of ​​the magnetic core, the number of turns of the main reactance coil, the residual surge current under high inductance conditions, the duration of the lightning pulse, the equivalent frequency of the lightning pulse, and the second air gap, it can be determined that... The length is determined through magnetic circuit calculation, finite element simulation, or surge test.

[0096] The main lightning current is discharged first through the input-side surge protector 610, while the second air gap is preserved. By selecting materials with high saturation flux density, adopting segmented windings or multi-magnetic circuit shunt structures, and ensuring that the maximum working flux density meets the above verification relationship, the risk of the magnetic core entering saturation due to residual surges or multi-pulse lightning strikes under high inductance conditions can be reduced, and the decrease in inductance, reduction in pulse impedance, and failure of isolation and suppression capabilities caused by magnetic core saturation can be avoided.

[0097] The controller structure is as follows: like Figure 10 As shown, the controller 500 includes a lightning detection interface, a current sampling interface, a voltage sampling interface, a signal conditioning module, an isolation protection module, a threshold judgment module, a microcontroller, a drive output module, a drive coil power supply module, a status feedback module, an alarm module, and a communication module.

[0098] The lightning detection interface connects to the lightning detection circuit 700 to receive lightning detection signals. The current sampling interface connects to the current sampling unit 300 to receive the leakage current signal from the surge protector's grounding conductor. The voltage sampling interface connects to the voltage sampling unit 400 to receive the grounding voltage difference signal between indoor and outdoor grounding points.

[0099] The signal conditioning module is used to filter, shape, limit, and isolate the lightning detection signal, leakage current signal, and ground voltage difference signal. The threshold judgment module is used to determine whether the lightning detection signal, leakage current, leakage current change rate, ground voltage difference, and their polarity reversal state meet the corresponding triggering conditions.

[0100] The microcontroller is used to perform pre-trigger judgment, power-side lightning strike event confirmation, ground-side backflash event judgment, hold timing, repeated trigger delay, reset confirmation, and alarm control. The drive output module is used to control the energization or de-energization of the magnetic core engagement drive coil 70. The drive coil power supply module is used to provide DC drive current to the magnetic core engagement drive coil 70.

[0101] The status feedback module is used to collect data on drive coil current, core position, surge protector status, lightning detector status, and backup protector status. The alarm module and communication module are used to output local or remote alarm information when the surge protector deteriorates, the backup protector trips, the drive coil malfunctions, or the core operates abnormally.

[0102] The control method for this isolation lightning protection reactor is as follows: like Figure 11As shown, the isolation lightning protection reactor in this embodiment can operate according to the following control method. The controller 500 receives the lightning detection signal output by the lightning detection circuit 700, the surge protector discharge current signal output by the current sampling unit 300, and the ground voltage difference signal output by the voltage sampling unit 400, and controls the power supply side variable reactor 100 and the ground side variable reactor 200 to switch between low inductance state and high inductance state according to different detection signals.

[0103] In this embodiment, the controller 500 can divide the operating state of the isolation lightning protection reactor into normal operation state, power supply side pre-trigger state, power supply side lightning strike event confirmation state, grounding side backflash event state, high inductance holding state, and reset confirmation state. The power supply side variable reactor 100 and the grounding side variable reactor 200 can enter their respective states independently, or they can enter the high inductance state simultaneously under combined lightning strike conditions.

[0104] S1, collects lightning detection signals and surge protector leakage current from the power supply side: like Figure 2 , Figure 10 and Figure 11 As shown, the lightning detection circuit 700 samples the transient voltage of the AC power line on the input side of the power supply-side variable reactor 100 and outputs the lightning detection signal to the controller 500. .

[0105] Lightning detection signal It can characterize the amplitude, envelope, or voltage rise trend of transient voltage in AC power lines. The controller 500 can continuously acquire lightning detection signals according to a preset sampling period and calculate the rate of rise based on the lightning detection signals at adjacent sampling times.

[0106] Meanwhile, the controller 500 collects the leakage current on the grounding wire of the input-side surge protector 610 and / or the output-side surge protector 620 through the current sampling unit 300. The rate of change of the discharge current is calculated based on the discharge current at adjacent sampling times.

[0107] The rate of change of the bleed current can be expressed as: ; in, for The leakage current on the grounding conductor of the surge protector at all times; This represents the discharge current at the previous sampling time. The time interval between two adjacent samples; This represents the rate of change of the discharge current at the current sampling moment.

[0108] The controller 500 can filter, limit, isolate, remove outliers, and continuously sample and confirm lightning detection signals and leakage current signals to reduce the probability of false triggering caused by power frequency voltage fluctuations, switching operation overvoltages, electromagnetic interference, and sensor noise.

[0109] S2, collecting ground voltage difference: like Figure 3 , Figure 10 and Figure 11 As shown, the controller 500 acquires the potential of the indoor protective ground or DC working ground through the voltage sampling unit 400. and the potential of the outdoor grounding terminal or lightning protection grounding body. The grounding voltage difference is calculated according to the following relationship: ; in, for The ground voltage difference at any given moment; for The potential of the outdoor grounding terminal or lightning protection grounding body at all times; for The potential of the indoor protective ground or DC working ground at all times.

[0110] when: When this occurs, it indicates that the potential of the outdoor grounding terminal or lightning protection grounding body is higher than the potential of the indoor protective ground or DC working ground, and there is a possibility that a backflash voltage may be generated from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground.

[0111] The controller 500 can also save the ground voltage difference at the previous sampling time. It is used to determine whether the polarity of the ground voltage difference has reversed and the direction of the voltage after the polarity reversal.

[0112] S3, determine whether the power supply side pre-trigger condition is met: The controller 500 determines whether there are any precursors to a lightning surge on the power supply side based on the lightning detection signal output by the lightning detection circuit 700.

[0113] In one implementation, the controller 500 determines that the power supply side pre-trigger condition is met when any of the following conditions are satisfied: or: ; in, for Lightning detection signal at any given moment; This is the lightning detection signal from the previous sampling time; This is the pre-trigger threshold for the lightning detection signal; This is the pre-trigger threshold for the rise rate of the lightning detector signal.

[0114] The transient voltage of the AC input line corresponding to the pre-trigger threshold of the lightning detection signal can be lower than the operating voltage of the input surge protector 610, so that the magnetic core of the power supply side variable reactor 100 can be activated in advance before the input surge protector 610 is officially turned on.

[0115] When the pre-triggering condition on the power supply side is met, the controller 500 outputs DC drive current to the magnetic core attraction drive coil 70 of the power supply side variable reactor 100 through the drive output module and the drive coil power supply module, so that the C-type magnetic core fixing iron block 50 drives multiple C-type magnetic cores 40 to move synchronously to the corresponding I-type magnetic core 30, and causes the power supply side variable reactor 100 to switch from a low inductance state to a high inductance state.

[0116] In this embodiment, the pre-trigger state can be referred to as the high inductance standby state. In the high inductance standby state, the controller 500 continues to collect lightning detection signals and surge protector discharge current to determine whether the pre-trigger will further develop into an actual lightning surge event.

[0117] If, within the preset event confirmation time, the controller 500 detects a surge protector discharge current that meets the power supply side lightning strike event confirmation conditions, it will switch the pre-trigger state to the power supply side lightning strike event confirmation state and maintain the power supply side variable reactor 100 in a high inductance state.

[0118] If no surge protector discharge current meeting the power supply side lightning strike event confirmation conditions is detected within the preset event confirmation time, and the lightning detection signal has fallen back below the lightning detection signal reset threshold, the controller 500 can cut off the DC drive current of the magnetic core engaging drive coil 70 after a preset reset confirmation time, so that the power supply side variable reactor 100 returns to a low inductance state, thereby reducing the long-term false holding caused by non-lightning transient signals.

[0119] In other alternative implementations, the pre-triggering conditions may also include one or more of the following: thunderstorm warning signal, local electric field strength exceeding a preset threshold, a micro-leakage in the surge protector grounding branch below the formal leakage trigger threshold but above the pre-triggering threshold, AC line voltage change rate exceeding a preset threshold, or ground potential change rate exceeding a preset threshold. The above additional pre-triggering conditions can be used in combination with lightning detection signals; however, in this embodiment, the lightning detection signal output by the lightning detection circuit 700 is preferentially used as the power supply-side pre-triggering basis.

[0120] S4, Determine whether the power supply side lightning strike event confirmation conditions are met: The controller 500 determines whether a power supply side lightning surge event has occurred based on the leakage current on the grounding wire of the input-side surge protector 610 and / or the output-side surge protector 620.

[0121] The controller 500 determines that the power supply side lightning strike event confirmation condition is met when any of the following conditions are met: or: ; in, The threshold for triggering the discharge current; The threshold for triggering the rate of change of the leakage current.

[0122] If the power supply side variable reactor 100 has not yet entered the high inductance state, the controller 500 outputs DC drive current to its magnetic core attraction drive coil 70, so that the power supply side variable reactor 100 switches from the low inductance state to the high inductance state.

[0123] If the power supply side variable reactor 100 has been pre-triggered by the lightning detection signal to enter the high inductance standby state, the controller 500 confirms the lightning strike event on the power supply side according to the surge protector discharge current, and maintains the power supply side variable reactor 100 in the high inductance state, while starting the high inductance hold timer.

[0124] The surge protector's discharge current can also be used to record the number of lightning strikes, the duration of lightning strikes, the peak value of the discharge current, the rate of change of the discharge current, and the operating status of the surge protector. It also serves as the basis for repeated trigger delays and reset confirmations under high inductance conditions.

[0125] After the lightning strike event on the power supply side is confirmed, the input surge protector 610 prioritizes discharging the main lightning current to the base station protection ground PE; the power supply side variable reactor 100 uses the higher pulse impedance formed under the high inductance state to suppress the residual surge from continuing to propagate to the next stage; the output side surge protector 620 performs secondary discharge of the residual surge after passing through the power supply side variable reactor 100.

[0126] S5, determine whether the grounding side backflash trigger condition is met: The controller 500 determines whether a grounding backflash event has occurred based on the magnitude, polarity, and direction of the polarity reversal of the grounding voltage difference.

[0127] When the following conditions are met: When the controller 500 determines that the outdoor grounding terminal or lightning protection grounding body has generated a positive potential rise relative to the indoor protective ground or DC working ground that reaches the backflash trigger threshold, the controller 500 determines that the outdoor grounding terminal or lightning protection grounding body has generated a positive potential rise relative to the indoor protective ground or DC working ground that reaches the backflash trigger threshold.

[0128] Or, when the following conditions are met: and: When the polarity of the ground voltage difference is reversed, the controller 500 determines that the polarity of the ground voltage difference has reversed, and the direction after the polarity reversal corresponds to the backflash direction from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground.

[0129] in, This represents the ground voltage difference at the previous sampling time; This is the threshold for triggering the counter-attack voltage.

[0130] When any of the above grounding backflash trigger conditions are met, the controller 500 outputs a DC drive current to the magnetic core attraction drive coil 70 of the grounding side variable reactor 200, causing the grounding side variable reactor 200 to switch from a low inductance state to a high inductance state.

[0131] Under high inductance conditions, the grounding-side variable reactor 200 forms a higher impedance to high-frequency lightning pulses and reverse ground potential rise, thereby reducing the risk of backflash voltage entering indoor communication equipment in the reverse direction along the grounding isolation branch.

[0132] The judgment of power supply side lightning strike events and grounding side backflash events are independent of each other. When only a power supply side lightning surge occurs, the controller 500 can drive only the power supply side variable reactor 100 into a high inductance state; when only a grounding side backflash voltage occurs, the controller 500 can drive only the grounding side variable reactor 200 into a high inductance state; when both types of events occur simultaneously, the controller 500 drives both variable reactors into a high inductance state respectively.

[0133] High inductance holding and repetitive trigger delay: After the power supply-side variable reactor 100 or the ground-side variable reactor 200 enters a high inductance state, the controller 500 maintains the corresponding magnetic core attraction drive coil 70 energized and performs timing according to the preset holding time.

[0134] High inductance hold time meets: ; in, For high inductance holding time; Based on the retention time; To maintain the number of times a lightning detection pre-trigger event, a power supply side lightning surge event, or a grounding side backflash event is detected again during the period; The duration to be maintained after each repeated trigger.

[0135] During the hold period, if the controller 500 detects again that the lightning detection signal meets the pre-triggering condition, the surge protector discharge current meets the power supply side event confirmation condition, or the ground voltage difference meets the ground side backflash triggering condition, the controller 500 can restart the hold timer or extend the hold duration by one additional time. .

[0136] Through the above-mentioned hold and repeated trigger delay control, the corresponding variable reactor can maintain a high inductance state during multi-pulse lightning strikes, continuous surges, or continuous ground potential backflashovers, avoiding frequent engagement and disengagement of the magnetic core between adjacent lightning pulses.

[0137] The power supply-side variable reactor 100 and the grounding-side variable reactor 200 can be set with different basic holding times, extended holding times, and maximum holding times. For example, the power supply-side holding time can be determined based on the duration of the lightning detection signal and the SPD leakage event; the grounding-side holding time can be determined based on the duration of the ground voltage difference and the ground potential recovery rate.

[0138] Power supply side reset control: When the power supply side variable reactor 100 is in a high inductance state, the controller 500 continuously collects lightning detection signals and surge protector discharge current.

[0139] When the following conditions are met: and: And continue power-side reset confirmation time At that time, the controller 500 determines that the lightning surge event on the power supply side has ended and cuts off the DC drive current of the magnetic core of the variable reactor 100 on the power supply side attracting the drive coil 70.

[0140] in, The lightning detector signal reset threshold; The bleed current reset threshold; This is the power supply side reset confirmation time.

[0141] The lightning detection signal reset threshold can be lower than the lightning detection signal pre-trigger threshold, and the leakage current reset threshold can be lower than the leakage current trigger threshold, so as to form a hysteresis interval between the trigger threshold and the reset threshold, preventing the power supply side variable reactor 100 from frequently engaging and disengaging when the detection signal fluctuates near the threshold.

[0142] Grounding side reset control: When the grounding-side variable reactor 200 is in a high inductance state, the controller 500 continuously collects the grounding voltage difference.

[0143] When the following conditions are met: And continue to confirm the grounding side reset time. At that time, the controller 500 determines that the grounding backflash event has ended and cuts off the DC drive current of the magnetic core attracting drive coil 70 of the grounding side variable reactor 200.

[0144] in, The ground voltage difference reset threshold; This is the time for confirming the reset on the grounding side.

[0145] The ground voltage difference reset threshold can be less than the backflash voltage trigger threshold to form a ground side trigger and reset hysteresis, preventing the ground side variable reactor 200 from frequently operating when the ground voltage difference changes near the threshold.

[0146] After the DC drive current of the magnetic core attraction drive coil 70 is cut off, the electromagnetic attraction force it generates disappears. The magnetic core separation spring 60 pushes the C-type magnetic core fixing iron block 50 to move in the opposite direction, so that the C-type magnetic core 40 separates from the I-type magnetic core 30, and the corresponding variable reactor returns to the low inductance state.

[0147] Abnormal status and backup protector control: Combination Figure 2 , Figure 10 and Figure 11 As shown, in one optional embodiment, the branches where the input-side surge protector 610 and the output-side surge protector 620 are located are respectively provided with a backup protector and a backup protector status detection unit.

[0148] The backup protector status detection unit is used to detect whether the backup protector has tripped, whether the surge protector has failed, and whether the discharge branch is abnormal, and sends the detection results to the controller 500.

[0149] When the controller 500 detects that the backup protector of any surge protector branch has tripped, the surge protector has failed, or the discharge branch is abnormal, the controller 500 may perform at least one of the following actions: Force the variable reactor 100 on the power supply side to be in a high inductance state; prohibit the use of the abnormal surge protector branch to continue to discharge current; allow another normal surge protector branch to handle surge discharge; output local alarm; send remote maintenance alarm to the base station monitoring platform through the communication module; record trip time, number of discharges, peak discharge current, peak ground voltage difference and abnormal type.

[0150] When some surge protector branches malfunction, the power supply-side variable reactor 100 can continue to maintain a high inductance state to improve the isolation capability between downstream equipment and lightning surges, and remind maintenance personnel to promptly inspect or replace the malfunctioning branch.

[0151] Determining the control parameters: Lightning detection signal pre-trigger threshold Lightning detector signal rise rate pre-trigger threshold Leakage current trigger threshold 1. Trigger threshold for leakage current change rate Counter-attack voltage trigger threshold Base retention time Repeated triggers extend the time The reset thresholds and reset confirmation times can be determined based on the following parameters: The rated voltage of the AC line, the operating voltage and nominal discharge current of the surge protector, the sampling ratio and response time of the lightning detection circuit 700, the sampling accuracy of the current sampling unit 300 and the voltage sampling unit 400, the processing time of the controller 500, the current settling time of the magnetic core engaging drive coil 70, the mechanical movement time of the C-type magnetic core 40, the power supply capacity of the base station, the grounding system structure, and the results of the lightning surge test.

[0152] In one embodiment, the controller 500 can also adaptively adjust the high inductance hold time or the repeated trigger extension time based on the number of lightning strikes detected, the peak value of the leakage current, the rate of change of the lightning detection signal, the peak value of the ground voltage difference, and the time interval between adjacent lightning strike events.

[0153] Through the above control methods, this embodiment can form a control closed loop of "lightning detection pre-triggering - SPD leakage event confirmation - power supply side high inductance maintenance - ground side backflash independent triggering - repeated triggering delay - power supply side and ground side independent reset", thereby reducing the mechanical core action lag and false triggering risk, and improving the adaptability of the isolation lightning protection reactor to power supply side surge, ground side backflash and combined lightning strike conditions.

[0154] The specific working process of this isolation lightning protection reactor is as follows: like Figure 1 , Figure 2 , Figure 8 and Figure 11 As shown, under normal power supply conditions, AC power supplies the base station switching power supply or other electrical equipment via the power supply-side variable reactor 100. At this time, the lightning detection signal output by the lightning detection circuit 700 does not meet the pre-triggering condition; both the input-side surge protector 610 and the output-side surge protector 620 are not conducting; the current sampling unit 300 does not detect a leakage current exceeding the leakage current trigger threshold; and the grounding voltage difference between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body does not meet the grounding side backflash triggering condition. The controller 500 does not output DC drive current to the magnetic core engaging drive coil 70 corresponding to the power supply-side variable reactor 100 and the grounding-side variable reactor 200.

[0155] Under the action of the magnetic core separation spring 60, the C-type magnetic core fixing iron block 50 drives the C-type magnetic core 40 away from the corresponding I-type magnetic core 30, so that the C-type magnetic core 40 and the I-type magnetic core 30 maintain the first air gap. Both the power supply-side variable reactor 100 and the grounding-side variable reactor 200 are in a low inductance state. At this time, the power supply-side variable reactor 100 forms a lower insertion impedance to the power frequency current, so as to reduce the power frequency voltage drop, core temperature rise and long-term operating losses under normal power supply conditions.

[0156] like Figure 1 , Figure 2 , Figure 9 and Figure 11 As shown, when a lightning surge precursor or transient overvoltage rises on the AC power input line, the lightning detection circuit 700 samples the transient voltage of the AC power input line and outputs a lightning detection signal to the controller 500. When the amplitude of the lightning detection signal reaches the pre-trigger threshold, or the rise rate of the lightning detection signal reaches the preset rise rate threshold, the controller 500 determines that there is a risk of lightning surge on the power supply side and outputs DC drive current to the magnetic core attraction drive coil 70 of the variable reactor 100 on the power supply side.

[0157] The magnetic core attraction drive coil 70 generates an electromagnetic attraction force, which drives the C-type magnetic core fixing iron block 50 to move multiple C-type magnetic cores 40 synchronously towards the corresponding I-type magnetic core 30, so that the air gap between the C-type magnetic core 40 and the I-type magnetic core 30 is reduced from the first air gap. Reduced to the second air gap This allows the power supply-side variable reactor 100 to switch from a low inductance state to a high inductance state earlier. Lightning detection pre-triggering is used to initiate the core engagement process earlier, reducing the response lag caused by the mechanical core action only starting after the surge protector is fully turned on.

[0158] When the input-side surge protector 610 or the output-side surge protector 620 is further turned on and generates a leakage current, the current sampling unit 300 detects the leakage current on the grounding wire of the surge protector. The system then sends the leakage current signal to the controller 500. The controller 500 determines whether the power supply side lightning strike event confirmation conditions are met based on the leakage current amplitude or leakage current change rate.

[0159] If the power supply-side variable reactor 100 has not yet entered the high inductance state, the controller 500 drives the power supply-side variable reactor 100 to switch to the high inductance state; if the power supply-side variable reactor 100 has already entered the high inductance state by pre-triggering of the lightning detection signal, the controller 500 confirms the lightning strike event on the power supply side according to the detected leakage current, and maintains the power supply-side variable reactor 100 in the high inductance state, while starting or restarting the high inductance holding timer.

[0160] When the power supply-side variable reactor 100 is in a high inductance state, the input-side surge protector 610 is used to prioritize the discharge of the main lightning current to the base station protective ground PE. The power supply-side variable reactor 100 uses the higher pulse impedance formed in the high inductance state to suppress the residual surge from continuing to propagate to the next stage. The output-side surge protector 620 is used to perform secondary discharge of the residual surge after passing through the power supply-side variable reactor 100, thereby reducing the residual surge voltage and surge energy borne by the base station switching power supply, communication main equipment and other electrical equipment.

[0161] When the lightning detection signal meets the pre-triggering condition, but neither the input-side surge protector 610 nor the output-side surge protector 620 generates a leakage current that meets the power supply-side lightning event confirmation condition within the preset confirmation time, the controller 500 continues to determine whether the lightning detection signal has fallen below the lightning detection signal reset threshold. If both the lightning detection signal and the leakage current are below the corresponding reset threshold and remain below the preset reset confirmation time, the controller 500 cuts off the DC drive current of the magnetic core engaging drive coil 70 of the power supply-side variable reactor 100, allowing the power supply-side variable reactor 100 to return to a low inductance state. This reduces the long-term false holding caused by non-lightning transient disturbances.

[0162] like Figure 3 , Figure 9 and Figure 11 As shown, when the outdoor grounding terminal or lightning protection grounding body discharges lightning current and causes its potential to rise, the voltage sampling unit 400 collects the potential of the indoor protective ground or DC working ground respectively. The potential of the outdoor grounding terminal or lightning protection grounding body It then outputs a ground voltage difference signal to controller 500. Controller 500 calculates the ground voltage difference using the following formula: ; When the amplitude of the ground voltage difference reaches the backflash voltage trigger threshold, or when the polarity of the ground voltage difference reverses and the direction after the reversal corresponds to the outdoor grounding terminal or lightning protection grounding body forming a backflash direction to the indoor protective ground or DC working ground, the controller 500 determines that there is a risk of backflash on the grounding side and outputs DC drive current to the magnetic core attraction drive coil 70 of the grounding side variable reactor 200.

[0163] Under the drive of the magnetic core attraction drive coil 70, the C-type magnetic core 40 of the grounding side variable reactor 200 moves closer to the corresponding I-type magnetic core 30, causing the grounding side variable reactor 200 to switch from a low inductance state to a high inductance state, and forming a higher impedance to high-frequency lightning pulses and reverse ground potential rise, thereby reducing the risk of backflash voltage entering indoor communication equipment in reverse along the grounding isolation branch.

[0164] like Figures 1 to 3 and Figure 11 As shown, when a lightning surge on the power supply side and a backflash voltage on the grounding side occur simultaneously, the controller 500 independently controls the variable reactor 100 on the power supply side and the variable reactor 200 on the grounding side to enter a high inductance state based on the lightning detection signal, the surge protector discharge current, and the grounding voltage difference signal, respectively.

[0165] The power supply-side variable reactor 100 uses lightning detection signals as pre-triggering criteria and surge protector discharge current or discharge current change rate as the basis for confirming lightning strike events and maintaining status on the power supply side. The grounding-side variable reactor 200 uses the amplitude, polarity, or backflash direction of the ground voltage difference as triggering criteria. The power supply-side variable reactor 100 and the grounding-side variable reactor 200 are not required to operate simultaneously, nor are they required to use the same high inductance holding time and reset conditions, thus enabling differentiated isolation and suppression for different lightning conduction paths.

[0166] After the power supply-side variable reactor 100 or the grounding-side variable reactor 200 enters a high inductance state, the controller 500 maintains the corresponding magnetic core attraction drive coil 70 energized and counts the time according to a preset holding time. During the holding period, if the controller 500 detects a lightning detector pre-trigger event, a surge protector leakage event, or a grounding-side backflash event again, it restarts the holding timer or extends the high inductance holding time according to the following formula: ; in, For high inductance holding time; Based on the retention time; To maintain the number of times the corresponding triggered event is detected again during the period; This is the additional hold time added after each repeated trigger. By setting the repeated trigger delay, the corresponding variable reactor can maintain a high inductance state during multi-pulse lightning strikes or continuous ground potential backflashes, avoiding frequent core engagement and disengagement.

[0167] like Figure 8 and Figure 11 As shown, after a lightning strike event on the power supply side ends, when the lightning detection signal is lower than the lightning detection signal reset threshold, the surge protector discharge current is lower than the discharge current reset threshold, and the preset reset confirmation time continues, the controller 500 cuts off the DC drive current of the magnetic core attracting drive coil 70 of the power supply side variable reactor 100.

[0168] After the grounding backflash event ends, when the absolute value of the grounding voltage difference is lower than the grounding voltage difference reset threshold and the preset reset confirmation time continues, the controller 500 cuts off the DC drive current of the magnetic core attracting drive coil 70 of the grounding side variable reactor 200.

[0169] After the DC drive current of the magnetic core attraction drive coil 70 is cut off, the electromagnetic attraction force it generates disappears, and the magnetic core separation spring 60 pushes the C-type magnetic core fixing iron block 50 to move in the opposite direction, causing the C-type magnetic core 40 to separate from the I-type magnetic core 30 and restore the first air gap. The corresponding variable reactor returns to a low inductance state, thus completing one isolation and lightning protection operation cycle.

[0170] In one alternative embodiment, the type I magnetic core 30 is fixed, and the type C magnetic core 40 is movable relative to the type I magnetic core 30; in another alternative embodiment, the type C magnetic core 40 is fixed, and the type I magnetic core 30 is movable relative to the type C magnetic core 40; in yet another alternative embodiment, both the type C magnetic core 40 and the type I magnetic core 30 are movable and can move closer to or further away from each other. All of the above embodiments can change the air gap between the type C magnetic core 40 and the type I magnetic core 30, allowing the magnetic circuit to switch between a separated state and an engaged or near-engaged state, thereby enabling the corresponding variable reactor to switch between a low inductance state and a high inductance state.

[0171] In one alternative embodiment, multiple C-type magnetic cores 40 are fixed on the same C-type magnetic core fixing block 50 and move synchronously under the action of the same driving mechanism, so that multiple reactance units corresponding to the A-phase line, B-phase line, C-phase line and N-line can switch inductance synchronously; in another alternative embodiment, different reactance units are provided with independent magnetic core fixing parts and driving mechanisms, and the controller 500 controls the operation of each driving mechanism, so that the reactance units corresponding to different phase lines or N-line can switch inductance independently.

[0172] In one alternative embodiment, the magnetic core attraction drive coil 70 is an electromagnetic attraction coil, which generates an electromagnetic attraction force by passing a DC drive current. In other embodiments, the drive mechanism for moving the C-type magnetic core 40 or the I-type magnetic core 30 can be a linear electromagnet, an electromagnetic push-pull actuator, a permanent magnet holding electromagnetic actuator, a motor screw mechanism, or a cam drive mechanism. The output end of the drive mechanism is connected to the C-type magnetic core fixing block 50, the I-type magnetic core fixing member, or the corresponding movable magnetic core, and is used to drive the movable magnetic core to move closer to or away from another magnetic core.

[0173] In one alternative implementation, the controller 500 employs a microcontroller; in other implementations, the controller 500 may employ a digital signal processor (DSP), a programmable logic controller (PLC), a field-programmable gate array (FPGA), or a control circuit composed of analog comparator circuits, logic control circuits, and drive circuits. The controller 500 is used to perform lightning detection pre-trigger judgment, surge protector leakage event confirmation, grounding side backflash event judgment, high inductance state maintenance, repetitive trigger delay, and reset control.

[0174] In one alternative implementation, the current sampling unit 300 employs a Hall current sensor; in other implementations, the current sampling unit 300 may employ a Rogowski coil, a current transformer, or a shunt resistor. The current sampling unit 300 is disposed on the grounding wire of the input-side surge protector 610 and / or the output-side surge protector 620, for acquiring the leakage current of the surge protector and outputting the leakage current signal to the controller 500.

[0175] In one alternative implementation, the voltage sampling unit 400 employs a resistor divider circuit and an isolation amplifier circuit; in other implementations, the voltage sampling unit 400 may employ a voltage transformer, an isolation amplifier, an opto-isolated sampling circuit, or an isolation analog-to-digital converter circuit. The voltage sampling unit 400 is used to acquire the potential of the indoor protective ground or DC working ground and the potential of the outdoor grounding terminal or lightning protection grounding body, and outputs a grounding voltage difference signal to the controller 500.

[0176] In one alternative embodiment, the lightning detection circuit 700 includes a resistor divider branch, a limiting protection branch, a peak detection branch, a filtering branch, and an isolated output branch, for outputting a lightning detection signal characterizing the transient voltage amplitude of the AC input line; in another alternative embodiment, the lightning detection circuit 700 includes a voltage sampling branch, a differential or rate of change extraction branch, a comparison branch, and an isolated output branch, for outputting a lightning detection signal characterizing the transient voltage rise rate of the AC input line; in yet another alternative embodiment, the lightning detection circuit 700 simultaneously outputs a transient voltage amplitude signal and a transient voltage rise rate signal, and the controller 500 determines whether the power supply side pre-triggering condition is met based on either signal or a combination of the two.

[0177] In one alternative implementation, the lightning detection circuit 700 samples phase A, phase B, and phase C independently; in another alternative implementation, the lightning detection circuit 700 performs time-division sampling of phase A, phase B, and phase C through a multiplexing circuit. When the lightning detection signal corresponding to any phase line meets the pre-triggering condition, the controller 500 drives the power supply-side variable reactor 100 into a high-inductance state.

[0178] Through the above structure and control method, this embodiment can solve the problem that fixed parameter reactors are difficult to balance between low insertion impedance during normal operation and high pulse impedance under lightning strike conditions; it can collect the transient voltage amplitude or rising trend of the AC input line through the lightning detection circuit 700, and start the high inductance switching of the power supply side variable reactor 100 in advance before the surge protector officially operates, and confirm the lightning strike event on the power supply side and maintain the high inductance state through the leakage current of the input side surge protector 610 and / or the output side surge protector 620; it can also use indoor protective grounding or direct current to achieve the desired high inductance state. The grounding voltage difference between the working ground and the outdoor grounding terminal or lightning protection grounding body allows for independent judgment of the grounding side backflash voltage, and controls the grounding side variable reactor 200 to switch between high and low inductance. It can also improve the response speed, control stability, reliability and adaptability of the isolation lightning protection reactor under communication base station lightning surge, grounding side backflash and combined lightning strike conditions through the relative movement of C-type magnetic core 40 and I-type magnetic core 30, automatic reset of magnetic core separation spring 60, high inductance holding, repeated trigger delay, independent reset, anti-saturation design and grounding safety boundary design.

[0179] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An isolation lightning protection reactor, characterized in that: The isolation lightning protection reactor includes a power supply side variable reactor, a grounding side variable reactor, a lightning detection circuit, an input side surge protector, an output side surge protector, a current sampling unit, a voltage sampling unit, and a controller. The power supply side variable reactor is connected in series between the three-phase four-wire AC power input terminal and the AC input terminal of the base station switching power supply or electrical equipment. The three-phase four-wire AC power input terminal includes phase A, phase B, phase C and N. The power supply side variable reactor includes four reactor units, and each phase and N line is connected in series with one reactor unit. The input-side surge protector is connected in parallel to the input side of the power supply-side variable reactor, and the output-side surge protector is connected in parallel to the output side of the power supply-side variable reactor. One end of the input-side surge protector and the output-side surge protector are respectively connected to the corresponding phase line or neutral line, and the other end is connected to the base station protection ground, so that the input-side surge protector, the power supply-side variable reactor, and the output-side surge protector together form a π-type discharge-isolation-discharge structure. The lightning detection circuit is installed on the line side of the surge protector on the input side. The voltage sampling terminal of the lightning detection circuit is connected to the AC power line on the input side of the variable reactor on the power supply side. The detection signal output terminal of the lightning detection circuit is connected to the controller. The lightning detection circuit is used to collect the transient voltage of the AC power line and output the lightning detection signal to the controller. The current sampling unit is installed on the grounding wire of at least one of the input-side surge protectors and the output-side surge protectors. The current sampling unit is connected to the controller and is used to collect the leakage current of the corresponding surge protector. The grounding-side variable reactor is connected in series in the working ground branch between the DC48V working ground terminal of the base station switching power supply and the DC working ground bus of the base station, or in series in the grounding isolation branch between the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body; the two potential sampling terminals of the voltage sampling unit are respectively connected to the two ends of the grounding-side variable reactor, or respectively connected to the indoor protective ground or DC working ground and the outdoor grounding terminal or lightning protection grounding body. The voltage sampling unit is connected to the controller and is used to collect the grounding voltage difference. Both the power supply-side variable reactor and the grounding-side variable reactor include an I-type magnetic core, a C-type magnetic core, a main reactor coil, a C-type magnetic core fixing block, a magnetic core separation spring, and a magnetic core attraction drive coil. The main reactor coil is wound on the corresponding magnetic post of the I-type magnetic core, or sleeved in the magnetic circuit window formed by the combination of the I-type magnetic core and the C-type magnetic core. The C-type magnetic core and the I-type magnetic core can switch between a separated position and an attracted or near-attracted position. When the controller does not output DC drive current to the corresponding magnetic core attraction drive coil, the magnetic core separation spring keeps the C-type magnetic core and the I-type magnetic core separated, so that the corresponding variable reactor is in a low inductance state. When the lightning detection signal meets the pre-triggering condition, or when the leakage current or leakage current change rate meets the power supply side event triggering condition, the controller outputs DC drive current to the magnetic core attraction drive coil of the power supply side variable reactor, so that the power supply side variable reactor switches to the high inductance state. When the ground voltage difference reaches the backflash voltage trigger threshold, or when the ground voltage difference undergoes a polarity reversal and the direction after the reversal is from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground, the controller outputs a DC drive current to the magnetic core attraction drive coil of the grounding side variable reactor, causing the grounding side variable reactor to switch to a high inductance state. Among them, the power supply-side variable reactor and the grounding-side variable reactor switch independently according to their respective triggering conditions.

2. The isolation lightning protection reactor according to claim 1, characterized in that: The four reactor units of the power supply-side variable reactor correspond to phase A, phase B, phase C, and N lines, respectively. Each reactor unit includes a main reactor coil, an I-type magnetic core, and a C-type magnetic core. The four main reactor coils are electrically independent of each other. The four C-type magnetic cores are fixed side by side on the same C-type magnetic core fixing iron block and can synchronously approach or move away from the corresponding I-type magnetic core under the drive of the same magnetic core attraction drive coil.

3. The isolation lightning protection reactor according to claim 1, characterized in that: The lightning detection circuit includes a voltage sampling terminal, a detection unit, and a detection signal output terminal. The detection unit is used to detect the transient voltage of the AC power line and output a lightning detection signal that characterizes the amplitude or rate of rise of the transient voltage. The controller determines whether the lightning detection signal meets the pre-triggering condition based on any of the following conditions: or: ; in, for Lightning detection signal at any given moment; This is the lightning detection signal from the previous sampling time; Sampling time; The time interval between two adjacent samples; This is the pre-trigger threshold for the lightning detection signal; This is the pre-trigger threshold for the rise rate of the lightning detector signal; When any of the above conditions are met, the controller will drive the power supply-side variable reactor to switch from a low inductance state to a high inductance state in advance.

4. The isolation lightning protection reactor according to claim 1, characterized in that: The current sampling unit is a Hall current sensor, a Rogowski coil, a current transformer, or a shunt resistor; The controller determines whether the power supply side lightning strike event trigger condition is met based on any of the following conditions: or: ; in, for The leakage current on the grounding conductor of the surge protector at all times; This represents the discharge current at the previous sampling time. Sampling time; The time interval between two adjacent samples; The threshold for triggering the discharge current; The trigger threshold is the rate of change of the discharge current; When any of the above conditions are met, the controller drives the power supply-side variable reactor to switch from a low inductance state to a high inductance state; when the power supply-side variable reactor has already entered the high inductance state by the lightning detection signal, the controller maintains the power supply-side variable reactor in the high inductance state.

5. The isolation lightning protection reactor according to claim 1, characterized in that: The voltage sampling unit includes an indoor potential sampling terminal, an outdoor potential sampling terminal, a voltage divider circuit, an isolation conditioning circuit, and a filter circuit. The indoor potential sampling terminal is connected to the indoor protective ground or DC working ground, and the outdoor potential sampling terminal is connected to the outdoor grounding terminal or lightning protection grounding body. The controller calculates the ground voltage difference according to the following relationship: ； in, for The ground voltage difference at any given moment; For sampling time or time variables; for The potential of the outdoor grounding terminal or lightning protection grounding body at all times; for The potential of the indoor protective ground or DC working ground at all times; When the following conditions are met: Or it satisfies: and: When the controller determines that there is a backflash voltage conducted from the outdoor grounding terminal or lightning protection grounding body to the indoor protective ground or DC working ground, it drives the grounding side variable reactor to switch from a low inductance state to a high inductance state. in, This represents the ground voltage difference at the previous sampling time; The counter-attack voltage trigger threshold; This represents the time interval between two adjacent samples.

6. The isolation lightning protection reactor according to claim 1, characterized in that: The inductance in the low inductance state is The inductance in the high inductance state is Both conditions are met: ； in, The inductance of the power supply-side variable reactor, the grounding-side variable reactor, or the reactor unit in a low inductance state; The inductance of the power supply-side variable reactor, the grounding-side variable reactor, or the reactor unit in a high inductance state; To increase the inductance factor, and Not less than 5.

7. The isolation lightning protection reactor according to claim 6, characterized in that: The inductive reactance of the power supply-side variable reactor or the ground-side variable reactor at the corresponding frequency satisfies: ； in, For the corresponding frequency The lower resistance; The frequency is the current frequency. This represents the inductance in the corresponding state. AC power frequency Under these conditions, the low inductance state satisfies: ； At the equivalent frequency of lightning pulse Under these conditions, the high inductance state satisfies: ； in, The AC power supply frequency; This is the equivalent frequency of the lightning pulse current or the equivalent frequency corresponding to the rising edge of the lightning pulse. To allow for the upper limit of normal insertion impedance; The lower limit of the pulse impedance required for lightning surge suppression; At power frequency under low inductance conditions The calculated inductive reactance; For high inductance conditions, based on the equivalent frequency of the lightning pulse The calculated inductive impedance.

8. The isolation lightning protection reactor according to claim 1, characterized in that: The C-type magnetic core fixing block moves relative to the I-type magnetic core via a guiding mechanism, and the electromagnetic attraction force generated by the magnetic core attracting the driving coil satisfies: ； in, The electromagnetic attraction force generated by the magnetic core attracting the drive coil; The spring reaction force of the magnetic core separation spring; The guiding frictional resistance generated when the iron block fixing the C-type magnetic core moves along the guiding mechanism; Additional resistance is provided to account for vibration resistance requirements and safety margins; The spring reaction force of the magnetic core separation spring satisfies: ； in, For spring stiffness; The compression of the magnetic core release spring relative to its natural length or preload position; This is the preload force of the magnetic core separation spring.

9. The isolation lightning protection reactor according to claim 1, characterized in that: The C-type magnetic core and the I-type magnetic core retain a non-magnetic limiting air gap in the high inductance state, and the non-magnetic limiting air gap is 0.1mm to 2mm. The core saturation check of the variable reactor on the power supply side or the variable reactor on the ground side meets the following requirements: ； in, Maximum operating magnetic flux density; The saturation magnetic flux density of the magnetic core material; A safety factor of 0.6 to 0.9; To allow the maximum magnetic flux density.

10. The isolation lightning protection reactor according to claim 1, characterized in that: After the variable reactor on the power supply side or the variable reactor on the ground side enters the high inductance state, the controller determines the high inductance holding time according to the following relationship: ； in, For high inductance holding time; Based on the retention time; To maintain the number of times a lightning detection pre-trigger event, a power supply side lightning surge event, or a grounding side backflash event is detected again during the period; The duration to be maintained after each repeated triggering; When the variable reactor on the power supply side is in a high inductance state, the following conditions must be met: and: And continuously reset confirmation time When this happens, the controller cuts off the DC drive current of the magnetic core of the variable reactor on the power supply side to attract the drive coil; When the variable reactor on the ground side is in a high inductance state, the following conditions must be met: And continuously reset confirmation time At this time, the controller cuts off the DC drive current of the magnetic core of the variable reactor on the grounding side to attract the drive coil; After the DC drive current of the magnetic core attraction drive coil is cut off, the magnetic core separation spring drives the C-type magnetic core to separate from the I-type magnetic core, so that the corresponding variable reactor returns to the low inductance state. in, for Lightning detection signal at any given moment; The lightning detector signal reset threshold; for The leakage current on the grounding conductor of the surge protector at all times; The current discharge current reset threshold; for The ground voltage difference at any given moment; The ground voltage difference reset threshold; This is the reset confirmation time.

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