101 results about "Arc suppression" patented technology

The embodiment of the invention provides a distribution network line fault positioning method and system, and the method comprises the steps: determining a fault phase, and calibrating a fault moment; dividing the multi-branch line into a line partition and a branch line partition based on the distribution network topology; screening a target fault phase, calculating a fault phase current difference of adjacent detection points, and calculating a current abrupt change rate based on the fault phase current difference of the adjacent detection points; according to the arc suppression coil type and the fault transition resistance value, performing fitting to generate a partition threshold value; a suspected fault section is obtained according to the section threshold initial judgment section; calling a current abrupt change rate time sequence curve of upstream and downstream nodes of the suspected fault section, and checking a current difference amplitude change trend before and after the fault; for multi-branch topology, interference is eliminated through relevance of current abrupt change rates of a main line and branch lines, and finally a target fault section is locked. According to the invention, the problems of weak fault characteristic quantity and poor positioning reliability in a small current grounding mode can be effectively solved.

The invention provides a power distribution network single-phase earth fault processing and fault rapid regional isolation system for solving the problems existing in power distribution network single-phase earth fault regional isolation at present. The system is composed of an improved compensation damping type active intervention arc extinguishing device installed on a transformer substation bus, primary and secondary fusion intelligent switches installed at all nodes of a distribution line, and a primary and secondary fusion intelligent switch intelligent control terminal. When a single-phase grounding fault occurs, a grounding switch of the compensation damping type active intervention arc extinguishing device is switched on, a primary and secondary fusion intelligent switch control terminal of each node of a power grid generates corresponding low-resistance, medium-resistance and high-resistance zero-sequence protection fixed values, and when the single-phase grounding fault occurs, zero-sequence current protection is started to realize rapid fault area isolation of the single-phase grounding fault.

The invention discloses an electric arc dynamic suppression method for hot plugging of an electric meter connector, relates to the technical field of electric energy metering equipment, and aims to solve the problems of electric arc generation, overproof metering error and the like caused by passive protection and lack of dynamic cooperative control in the prior art. The core of the method is that gap distance and power grid voltage phase signals are acquired in real time through a microcontroller, and the plugging speed, the signal injection and the position fine adjustment are dynamically regulated and controlled in three stages of pre-contact, low-current transition and full connection; and a machine learning model is combined to optimize a parameter threshold value, a redundancy safety mechanism and a multi-phase electric meter cooperative control strategy, so that double management and control of arc peak energy and metering errors are realized. The method can actively inhibit arc generation, avoid connector ablation and insulation deterioration, guarantee metering continuity and accuracy, adapt to complex power grid and environment working conditions, and meet the precision requirement of the intelligent electric meter.

The invention discloses a generator stator grounding fault active arc extinction method based on double-loop quasi-PR control, and the method comprises the following steps: S1, monitoring the fundamental wave zero-sequence voltage and third harmonic voltage of a neutral point and a generator end of a generator, and carrying out the fault phase selection and positioning when a single-phase stator grounding fault occurs; s2, according to a fault positioning result, calculating a fault winding potential Ef, and setting a negative value-Ef of the fault winding potential Ef as a neutral point target compensation voltage; s3, a cascaded H-bridge converter is adopted as a topological structure of the active regulation and control device, and a double-closed-loop control framework composed of a voltage outer loop and a current inner loop is established; s4, setting quasi-PR control units for the fundamental wave component and the third harmonic component in the voltage outer ring and the current inner ring respectively; and S5, controlling the cascaded H-bridge converter to output a compensation voltage consistent with the target compensation voltage-Ef, and injecting the compensation voltage into the neutral point of the generator. The voltage regulation and control precision and the arc suppression speed in the active arc suppression process of the generator can be improved, and the operation safety and reliability of the generator are improved.

The invention provides an arc suppression coil grounding system zero-sequence overcurrent protection method based on zero-sequence voltage verification. The protection reliability is improved through multi-criterion fusion. The method specifically comprises the following steps: S1, arc suppression coil system fault starting criterion: monitoring a zero sequence voltage in real time, and triggering a protection algorithm when the amplitude of the zero sequence voltage exceeds a preset threshold value; s2, fault time calculation: calculating the duration time of a grounding fault based on the duration characteristic of the zero-sequence voltage; s3, fault position discrimination: in combination with the amplitude characteristics of the zero-sequence current, distinguishing an internal fault from an external fault; and S4, intelligent comprehensive decision making: fusing the transient and steady state characteristic quantities of the zero-sequence voltage and the zero-sequence current, and generating a protection action signal. According to the invention, by dynamically checking the correlation characteristics of the zero-sequence voltage and current, the problems of insufficient sensitivity and high maloperation rate of the traditional zero-sequence overcurrent protection in the arc suppression coil grounding system are effectively solved.

The application belongs to the field of power system fault diagnosis, and discloses a single-phase grounding fault determination method for a small current grounding system based on Bi-LSTM, which comprises the following steps: analyzing a model of a power system and actual dispatching data, building a computer numerical simulation model through the analyzed data, labeling fault data and non-fault data in the simulation data and the actual dispatching data, normalizing simulation and real-time dispatching characteristic data, making a training set and a test set of a Bi-LSTM model, and designing a fault line selection model based on Bi-LSTM and training and testing of the model. In the case of single-phase grounding, the application can quickly determine a fault line according to discrete dispatching data; compared with existing zero sequence current identification methods, the application does not require zero sequence current data, and has a higher identification rate in the case of neutral point grounding through an arc suppression coil or a fault point with high transition resistance, thereby realizing simple and efficient small current grounding fault line selection.

The utility model discloses a cabinet combination connecting structure of an arc suppression coil, which comprises a supporting plate, a double-thread screw is rotatably connected to the side inner wall of the supporting plate, a sliding block is in threaded connection to the side surface of the double-thread screw, a first clamping block is fixedly connected to the lower surface of the sliding block, a bottom plate is fixedly connected to the surface of one side of the clamping block, and a second clamping block is fixedly connected to the upper surface of the sliding block. A first spring is fixedly connected to the lower bottom wall of the supporting plate, a telescopic rod is fixedly connected to the end, away from the supporting plate, of the first spring, a buckle is fixedly connected to the side surface of the telescopic rod, an extension plate is fixedly connected to the side surface of the buckle, and a second spring is fixedly connected to the side surface of the extension plate. A top plate is fixedly connected to one end of the spring II away from the extension plate. Through the components, the positions of the sliding blocks on the supporting plate and the length of the telescopic rod after being pulled up can be adjusted to be used for being matched with the length and the height of the arc suppression coil, the device can be adjusted according to the size of the arc suppression coil, the fixing effect is improved, and the types of the matched arc suppression coil are increased.

The utility model discloses an active power distribution network fault simulation experiment platform which comprises a public network power supply module, a line switch module, a power distribution network line section module and a plug panel which are connected in sequence, and a wave recording detection and relay protection module, a fault simulation module, a distributed power supply module and a load module which are connected with the plug panel, the public network power supply module and the line switch module are connected with the plug panel. The public network power supply module comprises a switch control circuit, a power supply side circuit breaker, a control contactor, a transformer and a distribution network side circuit breaker which are connected in sequence; the transformer is connected with an arc suppression coil, and the arc suppression coil is connected with the plug panel. The device is novel and reasonable in design and convenient to operate, realizes simulation experiments of different normal operation modes and different fault types in the active power distribution network by setting different topological structures and adjusting the fault types, realizes acquisition of characteristic signals in faults for fault characteristic signal analysis, and is good in safety performance and high in reliability. And an experimenter can conveniently carry out a simulation experiment.

This invention provides an intelligent pressure relief device for power distribution cabinets based on arc suppression, belonging to the field of power distribution cabinet pressure relief devices. It includes a cabinet body and a cabinet door. The cabinet door is rotatably connected to the side wall of the cabinet body via multiple hinges. An outer shell is fixedly connected to the outer wall of the cabinet body, and a baffle is provided on the outer wall of the outer shell. A pressure relief port is provided on the side wall of the cabinet body, and a sealing plate is provided on the outer wall of the cabinet body. It also includes: an auxiliary component located inside the outer shell, used to prevent high pressure from forming inside the cabinet and to cool the cabinet; a trigger component located below the auxiliary component, used to prevent open flames from forming inside the cabinet; and a reinforcement component located inside the cabinet body, used to improve the stability of the cabinet door. This invention, through the pushing of the sealing plate, drives the fixed rod to move, causing the end of the lever to press against the push plate, allowing carbon dioxide to be injected into the interior of the cabinet, reducing the possibility of open flames.

The application discloses an arc-extinguishing coil insulation self-starting fire extinguishing device and a control method, and belongs to the technical field of arc-extinguishing coil insulation self-starting fire extinguishing devices. The device comprises an arc-extinguishing coil body, a fixing frame and a fire extinguishing mechanism. The arc-extinguishing coil body is arranged on the fixing frame. The fire extinguishing mechanism is installed on the fixing frame. The fire extinguishing mechanism is sleeved on the surface of the arc-extinguishing coil body. The device is used for solving the technical problem that the artificial fire extinguishing mode is used for extinguishing fire, human beings need to know the fire phenomenon in time, and human beings need to arrive at the fire site in time to extinguish the fire, thereby causing low fire extinguishing efficiency and easily leading to property loss. The device can realize real-time sensing of the surface temperature change of the arc-extinguishing coil body through the fire extinguishing mechanism. When the surface temperature of the arc-extinguishing coil body reaches a preset value, the fire extinguishing mechanism is used for cooling the surface of the arc-extinguishing coil body, so that the formation of combustion conditions is effectively reduced. When the arc-extinguishing coil body catches fire, the fire extinguishing mechanism is used for extinguishing the fire at the fire site of the arc-extinguishing coil body, so that the harm caused by the flame can be reduced, and the effect of extinguishing the fire can be achieved.

An electrical switch (1) for a load tap changer (2), the electrical switch (1) comprising: at least three electrical contacts (3a, 3b, 3c) connected to respective electrical conductors (4a, 4b, 4c); a switching device (5) configured to be movable between a plurality of positions (P1, P2), wherein the switching device (5) in each respective position (P1, P2) physically contacts a respective combination (C1, C2) of the electrical contacts (3a, 3b, 3c) to provide electrical contact between the electrical contacts in each respective combination (C1, C2) of electrical contacts (3a, 3b, 3c); a gas-tight sealed housing (6) providing an inner space (7) enclosing the electrical contacts (3a, 3b, 3c) and the switching device (5), the electrical conductors (4a, 4b, 4c) extending from the electrical contacts (3a, 3b, 3c) inside the inner space (7) of the housing (6) to outside the housing (6); and a control device (10) configured to control movement of the switching device (5). The inner space (7) is under vacuum or filled with arc suppressing gas. The control device (10) comprises an operating member (8) extending from outside the housing (6) into the inner space (7) of the housing (6), the operating member being operatively connected to the switching device (5) such that the operating member (8) is able to move the switching device (5) to the plurality of positions (P1, P2) depending on the position of the operating member (8). Further, the operating member (8) comprises an arm (9) rotatably attached to the housing (6) for rotation about an axis of rotation (11), wherein the switching device (5) is attached to an end portion of the arm such that the switching device (5) is movable along an arcuate path between the plurality of positions.

A voltage arc suppression control method for single-phase ground faults in distribution networks belongs to the field of active arc suppression technology for single-phase ground faults in distribution networks. Its features include the following steps: Step a, acquiring signals; Step b, determining whether a ground fault has occurred; Step c, applying compensation based on a step coefficient k; Step d, determining whether the arc has been extinguished; Step e, determining whether the step coefficient k equals 1; Step f, applying compensation based on a secondary coefficient p; Step g, determining whether the arc has been extinguished; Step h, determining whether the secondary step coefficient p equals 0.1; Step i, the active inverter is continuously engaged according to the current output voltage. In this voltage arc suppression control method for single-phase ground faults in distribution networks, the impedance angle of the faulted line is used to determine the phase angle of the voltage drop from the fault point to the busbar, solving the problem that existing voltage arc suppression methods cannot reliably extinguish the arc and cause the fault current to increase instead of decrease when the fault point is far from the busbar and the fault transition resistance is small.

The utility model discloses an arc extinguishing coil assembly and switch assembly, the outer ring of arc extinguishing coil assembly, upper insulating pad, lower insulating pad and coil cover are set in the outer circumference of inner ring, and the coil is set between the outer ring and inner ring, and the upper insulating pad is set in the outer ring and the top of coil, and the lower insulating pad is set in the outer ring and the bottom of coil, and the inner ring bottom is provided with lower flanging, and the inner ring top is provided with upper flanging, and lower flanging and upper flanging cooperate and compress the lower insulating pad and upper insulating pad to be fixed on the outer ring and coil, and upper flanging is integrally formed on the inner ring. The utility model discloses the inner ring by riveting pressure's mode integrally forms upper flanging, and upper flanging and lower flanging cooperate and compress the lower insulating pad and upper insulating pad to be fixed on the outer ring and coil, and the structure is more compact, eliminates the risk of falling off, and is more safe and reliable.

The application provides a small-current grounding system single-phase grounding fault line selection method, and relates to the technical field of power distribution network fault detection.The method calculates the capacitive current of the system according to the measured zero sequence current data, counts and sums the capacitive current of each line to obtain the total capacitive current of the system, calculates the compensation degree of the arc suppression coil, extracts the fault characteristics, identifies the fault line after data processing and correction, compares the corrected zero sequence current signals of the fault line and the non-fault line, determines the fault line according to the difference between the corrected zero sequence current signals, and has high practicability and wide application prospect.

The utility model provides a capacitance current measuring circuit of a grounding system through a phase-controlled arc suppression coil, which comprises a phase-controlled arc suppression coil and a voltage source circuit, and is characterized in that the voltage source circuit is connected in parallel with a filtering winding of the phase-controlled arc suppression coil and is used for injecting voltage into the phase-controlled arc suppression coil; the power supply circuit comprises a capacitor Xcx, a transformer T2, a solid-state switch and an alternating-current power supply; the capacitor Xcx is used for dividing voltage and limiting voltage applied to the two ends of the filter winding induction coil; the capacitor Xcx is connected in series to one side of the transformer T2, the other side of the transformer T2 is connected in series with the solid-state switch, and one side of the solid-state switch is externally connected with an alternating current power supply. The voltage source circuit is introduced to be connected with the filtering winding of the phase-controlled arc suppression coil in parallel, voltage is injected into the phase-controlled arc suppression coil, the capacitive current of a grounding system can be accurately measured, the capacitor Xcx not only plays a role in voltage division, but also effectively limits the voltage applied to the two ends of an induction coil of the filtering winding, and therefore the voltage of the grounding system can be accurately measured. And the safety and the stability of the circuit are improved.

The invention discloses a longitudinal differential protection method and system based on crossed and overlapped difference, and the method comprises the steps: obtaining the accumulated break variables of voltage and current at a fault moment through SOD calculation according to the original three-phase voltage and current signals at two ends by using the break variables of electrical quantities at two ends of a line during the line fault; the method comprises the following steps: multiplying a voltage accumulated break variable by a current accumulated break variable to obtain power accumulated break variables on two sides, constructing a logarithmic function about the power accumulated break variables on a distributed power supply side and a power grid side, then obtaining a quadratic coefficient through a probability value self-adaptive attenuation function, comparing the quadratic coefficient with a set threshold value, and finally obtaining a maximum value of the distributed power supply side and the power grid side. And internal and external faults are checked. According to the method, only three-phase voltage and current at two sides need to be acquired, data acquisition is convenient, weak fault information can be effectively highlighted through SOD, influence of a neutral point arc suppression coil is avoided, faults inside and outside a region can be reliably detected, weak fault information can be better utilized, and weak feedback influence of a distributed power supply is reduced.

The invention provides an overvoltage tuning method and system based on parallel cooperation of a resistor and an arc suppression coil. The method comprises the following steps: judging an event type according to a neutral point voltage; when the event type is that the operation mode is changed, performing first tuning based on a first preset rule, and judging whether the neutral point voltage after the first tuning is greater than a threshold value or not; if the neutral point voltage after the first tuning is greater than the threshold value, performing secondary tuning based on a second preset rule, and judging whether the neutral point voltage after the secondary tuning is less than the threshold value; if the voltage of the neutral point after secondary tuning is larger than or equal to the threshold value, a second preset rule continues to be executed until the voltage of the neutral point after secondary tuning is smaller than the threshold value, and if the voltage of the neutral point after secondary tuning is smaller than the threshold value, it is judged that damping succeeds, and the resistance grounding device is reset. According to the invention, a unified zero-sequence impedance regulation and control strategy is established through cooperation of arc suppression coil operation and damping, so that the probability of occurrence of tuning overvoltage is reduced.

The utility model relates to the technical field of arc suppression coils, and discloses a high-capacity arc suppression coil structure, which comprises a protection plate, the bottom of the protection plate is slidably connected with a cabinet body fixing seat, one side of the outer wall of the fixing seat is provided with a winding group, the lower surface of the protection plate is fixedly connected with a connecting plate, and the connecting plate is fixedly connected with the cabinet body fixing seat. A buffering assembly is arranged on the lower surface of the outer wall of the connecting plate and used for buffering vibration, a rotating shaft is rotationally connected to the interior of the connecting plate, a connecting rod is fixedly connected to the outer wall of the rotating shaft, and a damping assembly is arranged at one end of the connecting rod and used for reducing vibration generated during buffering of the protective plate. According to the anti-collision device, the problems that the resistance to external force impact of the structure is poor, mechanical damage is prone to occurring in long-term operation, the buffering protection capacity of the device is affected, and potential safety hazards are increased are solved, stable buffering protection is achieved, the anti-collision effect is achieved, and then the service life of the whole device is prolonged.

This invention discloses a digital simulation system and method for arc suppression coils. The digital simulation system includes an arc suppression coil digital simulation device and a host computer. The host computer communicates with the arc suppression coil digital simulation device via a USB interface, and the arc suppression coil digital simulation device communicates with the arc suppression controller under test via a serial port. The arc suppression controller under test also communicates with the host computer via a serial port. This invention uses a single digital simulation system to simulate a target arc suppression coil test system, allowing for convenient and on-site testing of the arc suppression controller under test. This improves test safety and eliminates the need for complex and bulky arc suppression coil bodies or tooling, providing arc suppression coil manufacturers with a convenient and safe testing method to verify the various functions of the arc suppression controller.

The invention discloses an arc suppression coil power distribution network arc grounding fault distance measurement method based on line double-end data analysis. The method comprises the steps that 1, phase sequence currents and phase sequence voltages of the two sides of a fault section are acquired; step 2, calculating fault point equivalent arc current and fault point equivalent arc voltage, constructing a fault point arc volt-ampere characteristic curve, and solving an arc grounding fault transition resistance curve; step 3, intercepting a resistance curve, extracting a steady-state arcing time period and calculating the resistance of the steady-state arcing time period; step 4, solving the accurate fault distance measurement function by using the accurate fault distance measurement function to obtain suspected fault points, and constructing a suspected fault point array; step 5, based on the suspected fault point array, setting suspected fault intervals with different lengths, solving positions and center points; step 6, setting a suspected fault interval length, and repeating the step 5 to obtain a position and a suspected fault distance array x; and step 7, eliminating abnormal values by using a quartile method, and determining a fault distance of final positioning.

A method and apparatus for controlling an arc suppression device of a three-phase electric network, the arc suppression device having an adjustable admittance connected between a neutral point of the three-phase electric network and earth, the apparatus being configured to determine a resonant frequency of a zero-sequence system of the three-phase electric network and determine, based on the determined resonant frequency of the zero-sequence system of the three-phase electric network, whether to initiate a tuning of the arc suppression device of the three-phase electric network.

The application provides an arc suppression device of a power lock, a power supply system and an electric vehicle, and relates to the electrical protection field.The device comprises a lock switch of the power lock and an RC absorption circuit.The RC absorption circuit comprises a resistor and a capacitor.The lock switch comprises a moving contact, a first stationary contact and a second stationary contact.One end of the resistor is electrically connected with the first stationary contact, and the other end of the resistor is electrically connected with one end of the capacitor.The other end of the capacitor is electrically connected with the second stationary contact, and the moving contact is drivingly connected with a lock core of the power lock.The arc suppression device can completely eliminate the arc spark generated when the power lock is turned on and turned off through the RC absorption circuit, can effectively resist the high-frequency vibration of the electric motorcycle and the corrosion of the hot and humid environment, ensures long-term stable operation, and realizes the multiple improvement of performance, reliability and economy through the modular design, which not only simplifies the installation process, but also seamlessly adapts to the existing power lock structure, significantly reduces the production cost and the transformation cost, and realizes the multiple improvement of performance, reliability and economy.

The application discloses a two-point grounding fault model analysis method under a neutral point non-effective grounding mode, and aims to solve the problem that the prior art lacks a unified accurate mathematical model applicable to a neutral point non-grounding and arc suppression coil grounding system under a same-phase two-point grounding fault. The method reconstructs a fault network topology, establishes a multi-element function equation group containing a fault position, a ground capacitance, an arc suppression coil parameter and a power supply initial phase angle, deduces an explicit analytic expression of zero sequence voltage and current and phase voltage and current, and realizes accurate characterization of a time-space evolution law of fault characteristic quantities by combining with state space method modeling transient process. By adopting the above technical scheme, the application can provide modeling basis which can be directly called for a high-fidelity simulation platform such as RTDS, and support intelligent protection algorithm development and fault diagnosis system optimization.

The present application relates to a plasma cavity arc suppression method, apparatus, and radio frequency power system. The method comprises the steps of: obtaining a reflection coefficient within a plasma cavity through arc detection sampling—the reflection coefficient includes an instantaneous reflection coefficient and an average reflection coefficient—; comparing the absolute value of the difference between the instantaneous reflection coefficient and the average reflection coefficient with a set reflection coefficient threshold; if it is determined that an arc has occurred within the plasma cavity based on the comparison result, freezing the operating parameters of the final corresponding reduction node of the radio frequency power system via a state machine, stopping the arc detection sampling, and instructing the control module of the PID controller to cut off the power output of the output terminal docked to the plasma cavity via the control module of the PID controller; and, after the arc within the plasma cavity has disappeared, instructing the control module of the PID controller to restore the power output of the output terminal and restore the arc detection sampling according to the operating parameters. High-precision arc suppression processing within the cavity has been achieved.

This invention discloses a method and system for arc suppression in distribution networks using distributed power electronic equipment in coordination. The method includes... n Distributed installation on the feeder of the distribution network i A power electronic device is connected to the medium-voltage side of the distribution network via a power electronic converter and then connected to the distribution network's ground loop via a zero-sequence channel. When the distribution network is in steady-state operation and there is a three-phase ground parameter imbalance, at least one power electronic device is controlled to output a compensation current into the distribution network. When a single-phase ground fault occurs, it will... i The power electronic equipment is grouped into a current support group and a voltage clamping unit, which switch to current arc suppression mode and voltage clamping mode respectively. When the single-phase ground fault disappears, the power electronic equipment exits the coordinated arc suppression mode and switches back to steady-state operation mode. This invention achieves stable and reliable suppression of arcs from single-phase ground faults.

The invention provides a control method and system of a gas shielded welding machine, and relates to the technical field of gas shielded welding, and the method comprises the following steps: responding to a first pressing instruction of a welding gun switch, controlling a wire feeding device to rotate, and judging whether to ignite an electric arc or not; after ignition, the combustion stage of the electric arc is identified through a classification model, and the arcing state, the molten drop necking state and the crater filling state are obtained; then responding to a welding gun switch loosening instruction, entering a self-locking welding state, generating a current adjusting signal according to an arcing state, outputting the current adjusting signal to a welding power supply, generating a wire feeding adjusting signal according to a molten drop necking state, and outputting the wire feeding adjusting signal to a wire feeding device; in the self-locking welding state, responding to a second-time pressing instruction of a welding gun switch, entering an arc suppression welding state, and adjusting welding power output parameters and the wire feeding speed according to the arc crater filling state; and finally, responding to a second loosening instruction of the welding gun switch, stopping wire feeding and outputting, and closing the protective gas in a delayed manner. The accuracy and stability of welding process control are improved.

The utility model provides an air gap adjusting type arc suppression coil with a movable iron core, which belongs to the technical field of arc suppression coils, and comprises a gap type arc suppression coil mechanism, the gap type arc suppression coil mechanism comprises a first support and a second support, an automatic tuning arc suppression coil is arranged between the first support and the second support, and a movable iron core is arranged between the first support and the second support. The automatic tuning arc suppression coil comprises a stator iron core, a rotor iron core and an arc suppression coil body, the arc suppression coil body is wound on the stator iron core, and the rotor iron core rotates in a cavity of the stator iron core. The impedance of the arc suppression coil is changed by utilizing the change of the air gap space, the stepping motor is adopted to drive the inductance coil iron core to adjust the air gap and compensate the inductance current, after high voltage is applied to the arc suppression coil, almost no vibration noise exists, the problems of internal looseness and larger and larger noise along with the increase of the service time do not exist, and the arc suppression coil has certain practical value.

The invention relates to a power distribution network neutral point grounding device and a capacitance measurement method. The device comprises a neutral point potential voltage transformer, a linked switch, a first mutual current sensor, a second current transformer and an adjustable resistor, wherein the voltage transformer is connected with an arc suppression coil and the linked switch; when the linked switch is in a first state, the linked switch, the first current transformer and the adjustable resistor form a first branch; when the linked switch is in a second state, the linked switch, the second current transformer and the adjustable resistor form a second branch; the adjustable resistor is located on a trunk of the first branch and the second branch; when the first branch is connected, the first branch is used for fault line selection of the power distribution network; when the second branch is connected, the second branch is used for measuring the capacitance current of the power distribution network. Through the linked switch and the adjustable resistor, integration of fault line selection and measurement functions is realized, and the resource utilization rate and the system reliability are improved.

This disclosure relates to a method and system for protecting a single-circuit line from repeated grounding faults in an arc suppression coil grounding system. The method involves determining whether a grounding fault has occurred on the corresponding line based on the negative-sequence measured impedance angle or negative-sequence measured admittance angle of the line in the arc suppression coil grounding system. The system is used to execute the above method. This disclosure can protect against repeated grounding faults at two points on a single circuit, and is unaffected by factors such as the location of the fault point and transition resistance. It also has the advantages of strong anti-interference ability, stability, applicability, and high sensitivity.

The invention relates to a multi-terminal arc suppression coil cooperative control method based on neutral point flexible grounding, and the method comprises the steps: a control host sends a compensation amount to a grounding transformer arc suppression coil host, and a control slave sends the compensation amount to each grounding transformer arc suppression coil slave; fault detection and phase selection; closed-loop control based on voltage; fault judgment: if the zero-sequence voltage of the system is reduced, judging that the fault is a single-phase instantaneous grounding fault; and if the zero sequence voltage of the system still exceeds 20% of the phase voltage after the injection of the neutral point current is stopped, determining that the fault is a permanent fault. A hierarchical cooperative control architecture is adopted, a master-slave mode is adopted, a control host of an arc suppression coil of a system substation serves as a master controller, a control slave of an arc suppression coil of a new energy plant station serves as slave equipment, and network plant arc suppression coil cooperative compensation is achieved through an optical fiber communication network; accurate supplement is carried out on the arc suppression coil, power frequency and active components are fully compensated, and 100% arc suppression is realized; the current injected into the neutral point of the flexible grounding device is dynamically adjusted, and the inductive and capacitive modes are automatically switched.