Device and method for generating long-distance resonance electrified passive graded switching large current

Abstract

The embodiment of the invention discloses a long-distance resonance electrified passive graded switching large current generation device and method, and the method comprises the steps: obtaining a high voltage needed by a high-voltage bus through a boost module, and obtaining a first current value which is measured by a current mutual inductance module and is output by an ice melting current generation module; and according to the first current value and a preset target current value, the capacity of a second load unit connected with the high-voltage bus and the reactive power output of the SVG regulation and control module are adjusted, so that the parallel resonance circuit is in a parallel resonance state, and ice melting or on-load examination is performed on the to-be-tested sample. The current generated by the parallel resonance circuit during parallel resonance flows through the to-be-tested sample to realize ice melting of the to-be-tested sample, a high-capacity power supply is not needed, the method is suitable for the fields of long-time on-load examination of power distribution equipment, cable through-flow heating ice melting and the like, and ice melting of a real relatively long overhead line is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal ice melting and load assessment of electric power equipment, and in particular to a long-distance resonant energized passive graded switching large current generating device and method. Background Art

[0002] At present, in response to the shortcomings of the current de-icing of distribution network overhead lines, which mainly relies on manual hammering methods, some domestic institutions have also studied new de-icing methods. For example, the technical method of using dual SVG hedging output is arranged at the head and end of the high-voltage busbar, with the head end SVG in constant voltage mode and the end SVG in constant power or constant current mode. The test lines and loads are equivalently simulated using the "proportional scaling" method of simulated impedance. This technology is mainly suitable for laboratory principle verification. The power supply capacity required is large, making it difficult to achieve de-icing of actually long overhead lines. Summary of the Invention

[0003] In view of this, the present invention provides a long-distance resonant live passive graded switching large current generating device and method.

[0004] The specific technical solution of the first embodiment of the present invention is: a long-distance resonant live passive graded switching large current generating device, which is used to use the current generated when the parallel resonant circuit in the device is in a parallel resonant state to perform ice melting or load assessment on the sample to be tested. The device includes: a boost module, an SVG control module, a current mutual induction module, an ice melting current generating module and a measurement and control module; the input end of the boost module is connected to a preset low-voltage power supply, the output end of the boost module is connected to the head end of the high-voltage bus, the head end of the high-voltage bus is also connected to one end of the SVG control module, the output end secondary signal of the SVG control module is connected to the measurement and control module, the end of the high-voltage bus is connected to one end of the current mutual induction module, the controlled end of the ice melting current generating module is electrically connected to the measurement and control module, the other end of the current mutual induction module is connected to the other end of the ice melting current generating module, the sample to be tested is located between the SVG control module and the ice melting current generating module, and the output end of the current mutual induction module is electrically connected to the measurement and control module block; the SVG control module and the ice-melting current generating module form a parallel resonant circuit; the boost module is used to boost the low voltage in the preset low-voltage power supply to obtain a high voltage, and send the high voltage to the high-voltage bus; the ice-melting current generating module includes at least one first load unit and a plurality of second load units; all the first load units are connected in parallel with all the second load units, and all the first load units and all the second load units are connected in parallel; the measurement and control module is used to receive the first current value measured by the current mutual sensing module, and adjust the capacity of the second load unit connected to the high-voltage bus and adjust the reactive output of the SVG control module according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the ice is melted on the sample to be tested; the first current value is the output current value of the ice-melting current generating module obtained by the current mutual sensing module based on the capacity measurement of the first load unit.

[0005] Preferably, the ice-melting current generating module includes a plurality of capacitive load units and a plurality of inductive load units.

[0006] Preferably, the ice-melting current generating module further includes reactors having the same number as the capacitive load units, discharge coils having the same number as the capacitive load units, and first switching switches having the same number as the capacitive load units; the capacitive load units are capacitors; one end of all the first switching switches is connected to one end of the current mutual inductance module, the other end of one of the first switching switches is connected to one end of the reactor, the other end of one of the reactors is connected to one of the capacitors, and each capacitor is connected in parallel with a discharge coil.

[0007] Preferably, the ice-melting current generating module further includes AC contactors having the same number as the inductive load units, damping resistors having the same number as the inductive load units, and second switching switches having the same number as the inductive load units; the inductive load units are compensation reactors; one end of all the second switching switches is connected to one end of the current mutual induction module, the other end of one of the second switching switches is connected to one end of the damping resistor, the other end of one of the damping resistors is connected to one of the compensation reactors, and each damping resistor is connected in parallel with an AC contactor.

[0008] Preferably, the method of adjusting the capacity of the second load unit connected to the high-voltage bus and the reactive output of the SVG control module according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the ice of the sample to be tested is melted, includes: obtaining a current deviation rate according to the first current value and the preset target current value; when the current deviation rate is greater than a preset threshold, adjusting the capacity of the second load unit connected to the high-voltage bus according to a preset capacity adjustment rule, and synchronously adjusting the reactive output of the SVG control module; obtaining a second current value measured by the current mutual induction module; taking the second current value as the first current value, and returning to the step of obtaining the current deviation rate according to the first current value and the preset target current value, until the current deviation rate is less than or equal to the preset threshold, so that the parallel resonant circuit is in a parallel resonant state and the ice of the sample to be tested is melted.

[0009] Preferably, the preset capacity adjustment rule includes: when the first capacity of the second load unit connected to the high-voltage bus is increased for the first time, the first capacity is n times the capacity of all the first load units; wherein n≥1; and each increase in the second capacity after the first increase is n times the capacity value of the last increase.

[0010] Preferably, the current deviation rate is obtained using the following formula:

[0011]

[0012] Wherein, ΔI is the current deviation rate, I 目标值 is the preset target current value, I 测量值 is the first current value.

[0013] Preferably, the device further comprises a third switching switch, one end of the third switching switch is connected to the end of the high-voltage bus, and the other end of the third switching switch is connected to the current mutual induction module.

[0014] The specific technical solution of the second embodiment of the present invention is: a method for generating large current with long-distance resonant live passive graded switching, which is applied to the long-distance resonant live passive graded switching large current generating device as described in the first embodiment of the present application. The method includes: accepting the first current value measured by the current mutual inductance module; adjusting the capacity of the second load unit connected to the high-voltage bus and adjusting the reactive output of the SVG control module according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and performing ice melting or load assessment on the sample to be tested.

[0015] Preferably, the preset target current value is achieved by adjusting the capacity of the capacitive load unit, the capacity of the inductive load unit, or a combination of the capacitive load unit capacity and the inductive load unit capacity, while controlling the voltage not to exceed the limit. When the voltage is high, the input amount of the inductive load unit is increased or the input amount of the capacitive load unit is reduced; when the voltage is low, the input amount of the inductive load unit is reduced or the input amount of the capacitive load unit is increased.

[0016] The implementation of the present invention will have the following beneficial effects:

[0017] The present invention utilizes a boost module to obtain the high voltage required by the high-voltage bus, obtains a first current value output by the ice-melting current generating module measured by a current mutual induction module, and adjusts the capacity of a second load unit connected to the high-voltage bus and the reactive output of the SVG control module according to the first current value and a preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the ice of the sample to be tested is melted.

[0018] The low-voltage power supply requires a small capacity and only needs to maintain a specific active power loss. The boost module is used to convert the low voltage in the low-voltage power supply to the high voltage required by the high-voltage bus, and the SVG and ice-melting current generation module at the head end are used to form a parallel resonant circuit. The current generated by the parallel resonant circuit during parallel resonance flows through the sample to be tested to melt the ice on the sample to be tested. There is no need to set up a large-capacity power supply. It is suitable for long-term load assessment of distribution equipment and cable current heating and ice melting, and can realize ice melting or load assessment of real long overhead lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 This is an electrical schematic diagram of a long-distance resonant live passive graded switching large current generating device;

[0021] Figure 2 The electrical schematic diagram of the device when the sample to be tested is an overhead line de-icing device;

[0022] Figure 3 The electrical schematic diagram of the device when the sample to be tested is a distribution transformer;

[0023] Figure 4a The diagram shows the compensation effect of the ice melting current generating unit when the corresponding SVG is put into operation in sequence.

[0024] Figure 4b This is the compensation effect diagram of the corresponding SVG when the ice melting current generating unit is put into use according to its capacity;

[0025] Figure 5 A flow chart of the steps of a method for generating a large current by passively switching a large current in a long-distance resonant manner;

[0026] Among them, 101, boost module; 102, SVG control module; 103, current mutual induction module; 105, measurement and control module; 1041, inductive ice-melting current generating unit; 1042, capacitive ice-melting current generating unit; 106, third switching switch; 107, capacitor; 108, reactor; 109, discharge coil; 110, first switching switch; 111, AC contactor; 112, damping resistor; 113, second switching switch; 114, compensation reactor. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] The terms "first," "second," and the like in the specification, claims, and drawings of this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules is not limited to the listed steps or modules but may optionally include steps or modules not listed, or may optionally include other steps or modules inherent to the process, method, product, or apparatus.

[0029] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] See also Figure 1 , is an electrical schematic diagram of a long-distance resonant live passive graded switching large current generating device in the first embodiment of the present application, which is used to use the current generated when the parallel resonant circuit in the device is in a parallel resonant state to perform ice melting or load assessment on the sample to be tested. The device includes: a boost module 101, an SVG control module 102, a current mutual induction module 103 and a measurement and control module 105; the input end of the boost module is connected to a preset low-voltage power supply, the output end of the boost module is connected to the head end of the high-voltage bus, the head end of the high-voltage bus is also connected to one end of the SVG control module, the output end secondary signal of the SVG control module is connected to the measurement and control module, the end of the high-voltage bus is connected to one end of the current mutual induction module, the controlled end of the ice-melting current generating module is electrically connected to the measurement and control module, the other end of the current mutual induction module is connected to the other end of the ice-melting current generating module, the sample to be tested is located between the SVG control module and the ice-melting current generating module, and the output of the current mutual induction module The end is electrically connected to the measurement and control module; the SVG control module and the ice-melting current generating module form a parallel resonant circuit; the boost module is used to boost the low voltage in the preset low-voltage power supply to obtain a high voltage voltage, and send the high voltage voltage to the high-voltage bus; the ice-melting current generating module includes at least one first load unit and multiple second load units; all the first load units are connected in parallel with all the second load units, and all the first load units and all the second load units are connected in parallel; the measurement and control module is used to receive the first current value measured by the current mutual sensing module, and adjust the capacity of the second load unit connected to the high-voltage bus and adjust the reactive output of the SVG control module according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and melts the ice on the sample to be tested; the first current value is the output current value of the ice-melting current generating module obtained by the current mutual sensing module based on the capacity measurement of the first load unit.

[0031] Specifically, Figure 1 The 10kV distribution network in China is an ungrounded system, operating in a three-phase balanced manner. Therefore, the neutral point of the ice-melting current generator module is also ungrounded. For personal safety reasons, only the device casing is grounded. If operating in a single-phase mode, the other end (neutral side) of the inductive and capacitive load units in this application should be grounded.

[0032] Specifically, the boost module is used to boost the 400V power supply to 10kV to meet the test requirements of the 10kV sample to be tested; the current mutual sensing module is a third current transformer CT3; the ice-melting current generating module includes at least one first load unit and multiple second load units, the first load unit is an initialized load unit, and the second load unit is a load unit that is switched on and off according to the needs of the device; the measurement and control module receives the first current value measured by the third current transformer CT3, where the first current value is the output current value of the ice-melting current generating module obtained by the current mutual sensing module based on the capacity measurement of the first load unit, and adjusts the capacity of the second load unit connected to the high-voltage bus and the reactive output of the SVG control module according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the ice of the sample to be tested is melted; the SVG control module is used to track the device status, quickly inject or absorb reactive power, and ensure that the device only requires a small power supply to achieve a large current output;

[0033] Specifically, the measurement and control module is used to detect the current in the main parts of the device in real time and perform operational control, including monitoring the power input current, SVG output current, ice-melting current generating module output current, etc.; and control is performed according to the target current value, including switching on and off the power switch, adjusting the SVG output, switching on and off the ice-melting current generating module branch, etc., so that the circuit is in a resonant state.

[0034] In a specific embodiment, the ice-melting current generating module includes multiple capacitive load units and multiple inductive load units. Specifically, the ice-melting current generating module includes an inductive ice-melting current generating unit 1041 and a capacitive ice-melting current generating unit 1042. The inductive ice-melting current generating unit 1041 includes multiple inductive load units, and the capacitive ice-melting current generating unit 1042 includes multiple capacitive load units. The inductive load unit can be equivalent to an inductive impedance, which is used to compensate for the capacitive parameters of the sample to be tested. When the loop capacitive impedance equals the compensated inductive impedance, the device is in a parallel resonant state. The capacitive load unit can be equivalent to a capacitive impedance, which is used to compensate for the inductive parameters of the sample to be tested. When the loop inductive impedance equals the compensated capacitive impedance, the device is in a parallel resonant state.

[0035] In a specific embodiment, the device further includes a third switching switch 106 , one end of the third switching switch is connected to the end of the high-voltage bus, and the other end of the third switching switch is connected to the current mutual induction module.

[0036] In a specific embodiment, the ice-melting current generating module further includes reactors 108 having the same number as the capacitive load units, discharge coils 109 having the same number as the capacitive load units, and first switching switches 110 having the same number as the capacitive load units; the capacitive load units are capacitors 107; one end of all the first switching switches is connected to one end of the current mutual inductance module, the other end of one of the first switching switches is connected to one end of the reactor, the other end of one of the reactors is connected to one of the capacitors, and each capacitor is connected in parallel with a discharge coil.

[0037] In a specific embodiment, the ice-melting current generating module further includes AC contactors 111, which are equal in number to the inductive load units, damping resistors 112, which are equal in number to the inductive load units, and second switching switches 113, which are equal in number to the inductive load units; the inductive load units are compensating reactors 114; one end of all the second switching switches is connected to one end of the current mutual inductance module, the other end of each second switching switch is connected to one end of the damping resistor, and the other end of each damping resistor is connected to a compensating reactor, and each damping resistor is connected in parallel with an AC contactor. Note that the diagram looks like a single-phase circuit diagram, but the actual application is three-phase balanced operation. The current 10kV power system is generally an ungrounded system, so the neutral point side of the inductive load unit and the capacitive load unit should not be grounded. However, if it is single-phase operation, then the neutral point side of the inductive load unit and the capacitive load unit should be grounded to form a current loop.

[0038] Specifically, the capacitive and inductive ice-melting current generating units are connected to the 10kV busbar via a third switching switch. The inductive ice-melting current generating unit consists of multiple branches, each of which includes a resistive load (R) connected in parallel to an AC contactor (KM) and an inductive load (BK) connected in series with it. The capacitive ice-melting current generating unit also consists of multiple branches, each of which includes a series inductor (CK), a capacitor (C) connected in series with it, and a discharge coil. Both the capacitive and inductive ice-melting current generating units contain at least three capacitive branches connected in parallel, with the capacity of each branch increasing in a 2n geometric progression (n = 0, 1, 2...), and the capacity of a single branch ranges from 100kvar to 1600kvar.

[0039] In a specific embodiment, the capacity of the second load unit connected to the high-voltage bus and the reactive output of the SVG control module are adjusted according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the ice of the sample to be tested is melted, including: obtaining a current deviation rate according to the first current value and the preset target current value; when the current deviation rate is greater than a preset threshold, adjusting the capacity of the second load unit connected to the high-voltage bus according to a preset capacity adjustment rule, and synchronously adjusting the reactive output of the SVG control module; obtaining a second current value measured by the current mutual induction module; using the second current value as the first current value, and returning to the step of obtaining the current deviation rate according to the first current value and the preset target current value, until the current deviation rate is less than or equal to the preset threshold, so that the parallel resonant circuit is in a parallel resonant state and the ice of the sample to be tested is melted.

[0040] In a specific embodiment, the preset capacity adjustment rules include: when the first capacity of the second load unit connected to the high-voltage bus is increased for the first time, the first capacity is n times the capacity of all the first load units; where n≥1; and each increase in the second capacity after the first increase is n times the capacity value of the last increase.

[0041] In a specific embodiment, the current deviation rate is obtained using the following formula:

[0042]

[0043] Wherein, ΔI is the current deviation rate, I 目标值 is the preset target current value, I 测量值 is the first current value.

[0044] Specifically, the hierarchical switching control method for adjusting the capacity of a capacitive load unit connected to a high-voltage bus according to a first current value and a preset target current value includes:

[0045] S1: Set the expected flow value I according to the nature of the circuit 目标值 ;

[0046] S2: Initialize the basic capacitive load unit (100kvar) or the basic inductive load unit (100kvar);

[0047] S3: CT3 is used to detect the flow current in real time and calculate

[0048] S4: When ΔI>10%, for the inductive sample circuit, a capacitive ice-melting current generating unit is put into operation according to the 2n level difference; for the capacitive sample circuit, an inductive ice-melting current generating unit is put into operation according to the 2n level difference; at the same time, the SVG automatic tracking compensation is adjusted;

[0049] S5: Repeat steps S3-S4 until ΔI≤10% or all branches are put into operation.

[0050] Specifically, when de-icing an overhead line, the line is capacitive. Initially, a 100kV inductive current generating unit is activated. If the current output from CT3 is lower than the target value, this indicates insufficient inductive impedance to resonate the circuit. Therefore, additional inductive branches are required. To optimize adjustment efficiency, a 2n-step differential approach is used. The next step is to activate a 200kV branch (disconnecting the original 100kV branch). If the current difference remains significant, the next step is to activate a 400kV branch (disconnecting the original 200kV branch). This continues in order, with the activated capacities being: 100kV, 200kV, 400kV, 800kV, 1600kV, and finally 3100kV (all activated). As inductive or capacitive branches are activated, the circuit parameters change, automatically adjusting the SVG output to bring the circuit as close to resonance as possible.

[0051] In a specific embodiment, an SVG control module includes a circuit breaker (DL), a disconnector (QS), a switching resistor box, and an SVG device connected to a 10kV busbar. The switching resistor box houses an AC contactor (KM1) and a switching resistor (R) connected in parallel to the AC contactor. A second current transformer (CT2) for measuring compensation current is connected in series between the switching resistor box and the SVG device. The output of the second current transformer is connected to the input of the measurement and control module, and the output of the measurement and control module is connected to the controlled terminal of the circuit breaker (DL), the resistor box AC contactor, and the SVG device, respectively. The SVG control module dynamically adjusts the SVG's own reactive power output based on the CT2 signal, automatically tracking and compensating for inductive or capacitive current in the device.

[0052] In a specific embodiment, a power switching switch is connected in series at each end of the boost module, a first current transformer (CT1) for detecting a power branch current signal is connected in series between the power switching switch near one end of the 10kV busbar and the boost transformer (TB-1), the output end of the first current transformer (CT1) is connected to the input end of the measurement and control module, and the output end of the measurement and control module is connected to the controlled ends of the two power switching switches respectively.

[0053] For capacitive samples, an inductive load unit should be put in. Capacitive samples include no-load overhead lines and cables. For inductive samples, a capacitive load unit should be put in. Inductive samples include transformers and voltage regulators.

[0054] Alternatively, the following can be used to determine the phase relationship: After connecting the sample to be tested, but before adding the SVG, inductive, or capacitive load unit branches, measure the phase of the circuit voltage and current at CT1. If the voltage phase angle minus the current phase angle is greater than 0, the sample is inductive; if the voltage phase angle minus the current phase angle is less than 0, the sample is capacitive.

[0055] In a specific embodiment, the samples to be tested are distribution equipment such as distribution transformers, medium voltage regulators, switches, wires, cables, low voltage cables, etc. For example, for transformers and low voltage cables, Figure 3 The reverse docking method can be used to test the load capacity and overload capacity of the transformer; for the voltage regulator, it can be used Figure 1 The series connection method can realize the load capacity test and overload capacity assessment of the voltage regulator; for switches, wires, cables, etc., Figure 1 The series connection method can realize long-term current flow test, overload capacity assessment, etc. In particular, for overhead lines, Figure 2 The method of large current flow is used to melt ice.

[0056] In a specific embodiment, CT1 measures the power supply input current, i.e., the current supplied by the power supply to the entire device. This value is used for power supply current monitoring and power switching. CT1 is used solely for monitoring, determining when to switch the power supply on or off. CT2 measures the output current of the SVG control module, monitoring its output and providing feedback to the SVG control module to adjust the SVG output. CT2 is also used solely for monitoring, monitoring the SVG's operating status. CT3 measures the output current of the ice-melting current generating module, monitoring its output and providing feedback to the SVG control module to adjust the SVG output. Numerically, CT1 + CT2 = CT3. The power supply only provides power to maintain device resonance and the circuit has power losses, so CT1 is relatively small. The difference between CT2 and CT3 currents is not significant, representing parallel resonant currents.

[0057] In this embodiment, the capacitive and inductive ice-melting current generating units are configured with five parallel inductive branches and five parallel capacitive branches, respectively. For example, if the branch inductive capacities are 100, 200, 400, 800, and 1600 kvar, respectively, and the single switching capacity is no greater than 1600 kvar, the inductive capacity adjustment range is 100 kvar to 3.1 Mvar. The corresponding SVG capacity can be 3.5 MVA, enabling graded regulation of different capacities. For example, a 10 kW resistive load is set for each branch to ensure sufficient damping against grid disturbances, ensuring that the grid characteristics of the real-world experimental device are consistent with those of the actual grid. Similarly, the configuration of branch capacitive capacities can refer to the inductive ice-melting current generating unit.

[0058] As needed, the test sample can be connected in series or in parallel between the SVG control module and the capacitive and inductive ice-melting current generating units. This system can deliver high currents to 10kV equipment, meeting requirements for long-term current-carrying capacity testing, load capacity assessment, and conductor ice-melting. Test samples include distribution transformers, medium-voltage regulators, switches, conductors, cables, low-voltage cables, loads, and other distribution equipment.

[0059] In a specific embodiment, under the condition of ensuring that the voltage does not exceed the limit, the compensation degree (that is, the amount of inductance or capacitance input) is adjusted to achieve the target current. If the inductance input is over-compensated (the loop is inductive), part of the capacitance can be input to offset the inductance, that is, the offset relationship between L and C is used to adjust the compensation degree, and the loop current and the terminal voltage are indirectly adjusted. Specifically, by adjusting the capacity of the capacitive load unit, the capacity of the inductive load unit, or adjusting the capacity of the capacitive load unit and the capacity of the inductive load unit in combination to achieve the preset target current value, while controlling the voltage not to exceed the limit, when the voltage is high, the amount of inductive load unit input is increased or the amount of capacitive load unit input is reduced, and when the voltage is low, the amount of inductive load unit input is reduced or the amount of capacitive load unit input is increased. The terminal voltage is monitored by PT1 to ensure that the line is always at a normal power supply voltage level.

[0060] In a specific embodiment, when testing a parallel sample, the sample may be an electrical device such as a parallel capacitor or a parallel reactor.

[0061] like Figure 2 When used to melt ice on overhead distribution lines, the line section to be melted is treated as a sample to be tested and connected in series to the device. When the capacitive and inductive ice-melting current generating units are switched on and off, the SVG control module is automatically controlled by the measurement and control module to form parallel resonance, generating a large current to flow through the line section to be melted, thereby achieving heating and ice melting of the conductors.

[0062] like Figure 3 When the sample to be tested is a distribution transformer or low-voltage equipment, it is necessary to connect the two distribution transformers in series and reversely to achieve medium-voltage-low-voltage-medium-voltage conversion, and equivalently connect them in series with the resonant circuit. Connect the connecting wires or low-voltage loads between the two distribution transformers and use them as the access device for the sample to be tested. When the capacitive and inductive ice-melting current generating units are switched on and off, the SVG control module is automatically controlled by the measurement and control module to form parallel resonance, thereby realizing load or current-carrying test.

[0063] During the flow test or ice melting, the measurement and control module of the present invention remotely sends adjustment instructions according to the capacity requirements of the sample to be tested, and controls the capacitive and inductive ice melting current generating unit branches to be put into operation in a certain time sequence and capacity order. The compensation effect diagram of the corresponding SVG is shown in the following figure. Figure 4a As shown in the figure, the compensation effect diagram of the corresponding SVG input according to capacity is as follows Figure 4bAt the end of the test, a remote shutdown command is sent to remotely control the intelligent measurement and control modules of the capacitive and inductive ice-melting current generating units, causing them to shut down in sequence according to a specific timing and capacity sequence, ensuring an optimized shutdown process and minimizing impact on the device.

[0064] During testing, the measurement and control module remotely adjusts the SVG control module. When remotely switching capacitive and inductive ice-melting current generating units, the SVG control module provides real-time tracking and compensation to maintain parallel resonance, enabling dynamic regulation. Remote switching of the SVG control module eliminates transient surges, closing inrush currents, and arc restrike, minimizing impact on the device.

[0065] In the specific embodiment, see Figure 5 , a flowchart of the steps of a method for generating a large current by passively switching a large current in a long-distance resonant live area in a second embodiment of the present application is provided, which is applied to the device for generating a large current by passively switching a large current in a long-distance resonant live area in a first embodiment of the present application, and is characterized in that the method includes:

[0066] Step 201: Accepting a first current value measured by the current mutual sensing module;

[0067] Step 202: Adjust the capacity of the second load unit connected to the high-voltage bus and the reactive output of the SVG control module according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and perform ice melting or load assessment on the sample to be tested.

[0068] In a specific embodiment, adjusting the capacity of a second load unit connected to the high-voltage bus and adjusting the reactive output of the SVG control module according to the first current value and a preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the sample to be tested is melted, includes:

[0069] Step 301: obtaining a current deviation rate according to the first current value and a preset target current value;

[0070] Step 302: When the current deviation rate is greater than a preset threshold, the capacity of the second load unit connected to the high-voltage bus is adjusted according to a preset capacity adjustment rule, and the reactive output of the SVG control module is adjusted synchronously;

[0071] Step 303: Acquire a second current value measured by the current mutual sensing module;

[0072] Step 304: Use the second current value as the first current value, and return to the step of obtaining the current deviation rate based on the first current value and the preset target current value, until the current deviation rate is less than or equal to the preset threshold value, so that the parallel resonant circuit is in a parallel resonant state and the sample to be tested is subjected to ice melting or load assessment.

[0073] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0074] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A long-distance resonant live passive graded switching large current generating device, used to use the current generated when the parallel resonant circuit in the device is in a parallel resonant state to melt ice or perform load testing on the sample to be tested, characterized in that: The device includes: a boost module, an SVG control module, a current mutual induction module, an ice melting current generation module and a measurement and control module; The input end of the boost module is connected to a preset low-voltage power supply, the output end of the boost module is connected to the head end of the high-voltage bus, the head end of the high-voltage bus is also connected to one end of the SVG control module, the output end secondary signal of the SVG control module is connected to the measurement and control module, the end of the high-voltage bus is connected to one end of the current mutual induction module, the controlled end of the ice-melting current generating module is electrically connected to the measurement and control module, the other end of the current mutual induction module is connected to the other end of the ice-melting current generating module, the sample to be tested is located between the SVG control module and the ice-melting current generating module, and the output end of the current mutual induction module is electrically connected to the measurement and control module; The SVG control module and the ice-melting current generating module form a parallel resonant circuit; The boost module is used to boost the low voltage in the preset low voltage power supply to obtain a high voltage, and send the high voltage to the high voltage bus; The ice melting current generating module includes at least one first load unit and a plurality of second load units; all the first load units are connected in parallel with all the second load units, and all the first load units are connected in parallel with all the second load units; The measurement and control module is used to receive a first current value measured by the current mutual sensing module, and adjust the capacity of a second load unit connected to the high-voltage bus and the reactive output of the SVG control module according to the first current value and a preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the sample to be tested is melted; the first current value is the output current value of the ice-melting current generating module obtained by the current mutual sensing module based on the capacity measurement of the first load unit.

2. The long-distance resonant live passive graded switching large current generating device according to claim 1, characterized in that: The ice-melting current generating module includes a plurality of capacitive load units and a plurality of inductive load units.

3. The long-distance resonant live passive graded switching large current generating device according to claim 2, characterized in that: The ice-melting current generating module further includes reactors having the same number as the capacitive load units, discharge coils having the same number as the capacitive load units, and first switching switches having the same number as the capacitive load units; the capacitive load units are capacitors; One end of all the first switching switches is connected to one end of the current mutual inductance module, the other end of one of the first switching switches is connected to one end of the reactor, the other end of one of the reactors is connected to one of the capacitors, and each capacitor is connected in parallel with a discharge coil.

4. The long-distance resonant live passive graded switching large current generating device according to claim 2, characterized in that: The ice-melting current generating module further includes AC contactors, damping resistors, and second switching switches, the number of which is the same as the number of the inductive load units; the inductive load units are compensating reactors; One end of all the second switching switches is connected to one end of the current mutual induction module, the other end of one of the second switching switches is connected to one end of the damping resistor, the other end of one of the damping resistors is connected to one of the compensating reactors, and each damping resistor is connected in parallel with an AC contactor.

5. The long-distance resonant live passive graded switching large current generating device according to claim 1, characterized in that: The adjusting the capacity of the second load unit connected to the high-voltage bus and the reactive output of the SVG control module according to the first current value and the preset target current value, so as to put the parallel resonant circuit in a parallel resonant state and melt the ice of the sample to be tested, includes: Obtaining a current deviation rate according to the first current value and a preset target current value; When the current deviation rate is greater than a preset threshold, the capacity of the second load unit connected to the high-voltage bus is adjusted according to a preset capacity adjustment rule, and the reactive output of the SVG control module is adjusted synchronously; Obtaining a second current value measured by the current mutual sensing module; The second current value is used as the first current value, and the process returns to the step of obtaining the current deviation rate based on the first current value and the preset target current value until the current deviation rate is less than or equal to a preset threshold value, so that the parallel resonant circuit is in a parallel resonant state and the sample to be tested is melted.

6. The long-distance resonant live passive graded switching large current generating device according to claim 5, characterized in that: The preset capacity adjustment rules include: When the first capacity of the second load unit connected to the high-voltage bus is increased for the first time, the first capacity is n times the capacity of all the first load units; wherein n≥1; Each second capacity increase after the first increase is n times the capacity value of the last increase.

7. The long-distance resonant live passive graded switching large current generating device according to claim 5, characterized in that: The current deviation rate is obtained using the following formula: Wherein, ΔI is the current deviation rate, I 目标值 is the preset target current value, I 测量值 is the first current value.

8. The long-distance resonant live passive graded switching large current generating device according to claim 1, characterized in that: The device further includes a third switching switch, one end of the third switching switch is connected to the end of the high-voltage bus, and the other end of the third switching switch is connected to the current mutual induction module.

9. A method for generating a large current by passively switching a large current in a long-distance resonant live area, applied to the device for generating a large current by passively switching a large current in a long-distance resonant live area as claimed in claim 1, characterized in that: Methods include: Accepting a first current value measured by the current mutual sensing module; The capacity of the second load unit connected to the high-voltage bus and the reactive output of the SVG control module are adjusted according to the first current value and the preset target current value, so that the parallel resonant circuit is in a parallel resonant state and the sample to be tested is subjected to ice melting or load assessment.

10. The method for generating large current by passive graded switching with long-distance resonant charging according to claim 9, characterized in that: The method further comprises: The preset target current value is achieved by adjusting the capacity of the capacitive load unit, the capacity of the inductive load unit, or a combination of the capacitive load unit capacity and the inductive load unit capacity, while controlling the voltage not to exceed the limit. When the voltage is high, the input amount of the inductive load unit is increased or the input amount of the capacitive load unit is reduced. When the voltage is low, the input amount of the inductive load unit is reduced or the input amount of the capacitive load unit is increased.

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