939results about "Impedence measurements" patented technology

The invention relates to the technical field of electrical variable measurement, and discloses an equipotential connection measurement method and system based on precise low resistance. The method comprises the steps that according to high-precision ADC chip sampling parameters and temperature sensor arrangement, initial configuration of measurement channels is completed to obtain a dynamic compensation parameter database, and meanwhile, 20 channels are connected through an elastic crimping structure to obtain stress compensation data; a dynamic calibration compensation coefficient is obtained by using a standard resistance network through time division multiplexing calibration in combination with temperature-resistance and stress characteristic analysis; performing four-wire system measurement and 1kHz sampling based on the coefficient to obtain original data; a resistance value is obtained through compensation processing and interference identification; performing correlation analysis to obtain state parameters; and finally, evaluating the stability to obtain an optimized compensation parameter. The method is used for solving the problem of dynamic interference caused by temperature change and mechanical stress in the equipotential connection resistance measurement process, and high-precision multi-channel measurement is achieved.

The present disclosure provides a method and device for calculating fault measurement impedance of a hybrid-connected grid-following and grid-forming wind power system. The method includes: obtaining characteristics of the grid-following and grid-forming converters and a corresponding low voltage ride-through control strategy; establishing an equivalent circuit under a corresponding fault state; conducting a simplified analysis on the wind power system to obtain an equivalent network diagram; obtaining a sub-circuit diagram of each power source excitation acting alone; obtaining short-circuit currents on both sides of the corresponding system and a grid connection point voltage; superimposing to obtain total short-circuit current on both sides of the wind power system and total grid connection point voltage; and obtaining a measurement impedance at a protection installation location on the new energy source side. The method can accurately calculate the measurement impedance value at the protection installation location after the wind power system has fault.

The present disclosure provides a fault measurement impedance calculation method and device for a hybrid grid-following / grid-forming wind power system. The method comprises: acquiring characteristics of a grid-following converter and a grid-forming converter, and corresponding low-voltage ride-through control strategies; establishing an equivalent circuit corresponding to a fault state; performing simplified analysis on a hybrid wind power system to obtain an equivalent network diagram; obtaining a branch circuit diagram under individual action of each power excitation; obtaining short-circuit currents and grid-connected point voltages on two sides of the system corresponding to the individual action of each power excitation; performing superimposition to obtain a total short-circuit current and a total grid-connected point voltage at the two sides of the hybrid wind power system; and obtaining a measurement impedance at a protection installation point on a new energy side. In the method, a measurement impedance value at a protection installation point of a hybrid wind power system after a fault occurs can be accurately calculated, so that the setting calculation of distance protection is ensured, so as to accurately reflect fault characteristic information of a hybrid AC system, thereby providing a basis for the distance protection applicability research of the hybrid wind power system, and thus ensuring the safe and stable operation of new energy systems.

A system includes a processing device and a measurement circuit coupled to the processing device. The system further includes an auxiliary voltage supply. The processing device and the measurement circuit are powered by the auxiliary voltage supply. The measurement circuit is to apply a test voltage to a first resistor and measure a voltage drop over the first resistor. The processing device is to determine, based on at least the voltage drop, an isolation resistance value between a chassis ground node and at least one of a battery pack or a battery link of a power system.

The invention provides a direct-current loop resistance testing system and method and a loop resistance tester, and relates to the technical field of resistance testing systems.The direct-current loop resistance testing system comprises an intelligent testing module, a temperature calibration module, a data analysis module, a data comparison module, a data calibration module, a data transmission module and a data display module; and the performance and the reliability of the direct-current loop resistance test system are obviously improved. The calibration coefficient is dynamically generated and repeatedly calibrated, so that manual intervention is reduced, and the precision of measured data and the automation degree of the system are improved. The mean value and the standard deviation are calculated through the moving average method, the dynamic threshold value is generated, abnormal data can be detected and recognized more accurately, it is ensured that the system can respond to and process abnormal conditions in real time, and the real-time performance and the response speed of the system are improved. In addition, a temperature calibration method is adopted to effectively compensate the influence of temperature change on the measurement resistance, and the adaptability and robustness of the system are enhanced.

A battery pack includes a plurality of battery subpacks and voltage detection circuits, a current detection circuit, and a BMS. Each battery subpack and one connection component connected to the battery subpack form one to-be-detected assembly. The current detection circuit is configured to detect a current of the charge / discharge loop. The voltage detection circuit is configured to detect voltages at two ends of the to-be-detected assembly. The BMS is configured to: obtain the current of the charge / discharge loop and voltages at two ends of each to-be-detected assembly based on a preset period, generate a current sequence and a first voltage sequence of each to-be-detected assembly, calculate an impedance of each to-be-detected assembly based on the current sequence and the first voltage sequence, and when the impedance is greater than or equal to an impedance threshold, determine that the connection component in the to-be-detected assembly is abnormally connected.

The invention relates to a lithium ion battery overcharge thermal runaway early warning method, early warning device and processing equipment, and the lithium ion battery overcharge thermal runaway early warning method comprises the steps: obtaining an electrochemical impedance spectrum of a lithium ion battery, and obtaining a single-point frequency in a low-frequency region of the electrochemical impedance spectrum; performing direct current charging on the lithium ion battery, and injecting an alternating current power supply of which the frequency is a single-point frequency into the lithium ion battery; acquiring a voltage component and a current component of the lithium ion battery under the alternating current power supply; acquiring the electrochemical impedance of the lithium ion battery according to the voltage component and the current component; and generating overcharge early warning information according to the condition that the imaginary part amplitude of the electrochemical impedance or the real part amplitude of the electrochemical impedance meets a preset condition. Through the technical scheme disclosed by the invention, the problem of lithium ion overcharge thermal runaway can be found in time, the problem of explosion fire caused by thermal runaway caused by lithium ion battery overcharge is avoided, and the operation safety of the energy storage system is ensured.

The invention relates to the technical field of harmonic impedance calculation, and discloses an injection type harmonic impedance measurement method based on a non-injection type prior result. The method comprises the following steps: firstly, collecting and processing related data on a PCC point, obtaining a related impedance prior model through a non-injection impedance measurement method, modeling background noise, designing a multi-sine disturbance signal of injection impedance measurement based on a non-injection impedance measurement prior result, then injecting and fitting an impedance curve, and finally obtaining a multi-sine disturbance signal. And then redesign and iterative fitting of the multiple sinusoidal signals are carried out according to the estimation error, and finally an impedance curve meeting the precision requirement is obtained. According to the method, the advantages of a non-injection type measurement method and an injection type measurement method are combined, through multiple rounds of measurement processes, the non-injection type method is firstly used for obtaining preliminary estimation of system side harmonic impedance, then the injection type method is used for further measuring and correcting harmonic waves with high specific attention, measurement errors are effectively reduced, and the measurement accuracy is improved. And the reliability of a measurement result and the rapidity of measurement are improved.

The embodiment of the invention discloses an insulation resistance detection circuit and an insulation resistance detection device of a battery module, and belongs to the technical field of resistance detection. Wherein the insulation resistance detection circuit comprises a detection port for detecting to-be-detected insulation resistance of the port to the ground, and the detection port of the insulation resistance detection circuit is connected to the positive electrode of any cell in the battery module; the processor is respectively connected with the first switch, the second switch and the voltage sampling unit, and is used for determining an impedance value of the to-be-detected insulation impedance and a voltage value of the detection port based on the voltage sampled by the voltage sampling unit in a process of controlling the connection or disconnection of the first switch and the second switch; when the insulation impedance of any cell is determined to be abnormal based on the impedance value of the to-be-detected insulation impedance, the number of cells to which any cell belongs in the battery module is determined based on the voltage value of the detection port, and the cells with abnormal insulation impedance in the battery module can be accurately determined.

The invention provides a method and a system for calculating power grid impedance based on a sliding window. The method comprises the following steps: setting a signal category and a signal length of a disturbance signal to be injected into an access power grid by a new energy station; according to the signal category, the new energy field station injects orthogonal signals with the same amplitude and frequency into a d axis and a q axis of an access power grid at the same time as disturbance signals; acquiring three-phase current data and voltage data of the signal length at a grid connection point; and calculating the power grid impedance at the target frequency based on a sliding window according to the three-phase current data and the voltage data. According to the method and the system, the electric energy quality during the disturbance injection period is improved, the noise interference resistance of impedance calculation is improved, and it is well ensured that an impedance measurement result with rapidness and accuracy is obtained within a wide frequency range.

In at least one embodiment, the operating method is for detecting an impedance (Zg) of a power grid (1) and comprises the following steps: - providing a positive sequence (P) by a power converter (2) to the power grid (1), the power grid (1) is provided by the power converter (1) with an alternating current, - injecting a negative sequence (N) by the power converter (2) into the power grid (1), - measuring a response of the power grid (1) to the negative sequence (N), and - online calculating the impedance (Zg) of the power grid (1) from the response.

A method for determining a leakage impedance of a transformer and an electric power converter configured to obtain values of a first voltage and a first current in an AC output of the electric power converter, a value of a second current between an output filter connected to the AC output and a primary side of a transformer connected to the output filter and a value of a second voltage on a secondary side of the transformer, wherein the values are obtained when the secondary side of the transformer is disconnected from an AC network, and to determine a leakage impedance of the transformer on the basis of the values of the first voltage, the first current, the second current and the second voltage, and at least one predetermined impedance parameter value of the output filter.

The present disclosure relates to apparatus and methods for determining a transfer function of a current measurement arrangement (118), or a change in a transfer function of the current measurement arrangement. In one aspect, an apparatus is disclosed comprising: a signal source (112) configured to apply a reference signal to a first current transducer (110) such that a first transducer output signal from the first current transducer comprises: a current measurement signal indicative of the first current passing through a first conductor (104); and a reference signal component resulting from the reference signal; and signal processing circuitry (116)configured to determine the transfer function of the current measurement arrangement by: extracting the reference signal component from the first transducer output signal; and determining the transfer function of the current measurement arrangement based on the transducer output signal.

An aerosol-generating device may be provided, the device comprising: a housing; a heater assembly including an oscillation unit for generating microwaves of a designated frequency band and a resonance unit for receiving the generated microwaves from the oscillation unit through a coupler and resonating the received microwaves to generate an electric field; a sensor disposed inside the housing and for detecting the insertion of a metal into a receiving space for receiving an aerosol-generating article; and a processor electrically connected to the sensor and cutting off the supply of power to the oscillation unit when insertion of a metal into the receiving space is detected by the sensor.

A method for monitoring the line impedance of a protective earth (“PE”) conductor is provided. The method injects a small stimulus current at a frequency much higher than the grid frequency. The stimulus current circulates in the loops between a grid-connected device and a grid source, creating small voltage drops in the grid conductors, resulting in a common mode voltage which can be measured. The method then includes measuring the common mode voltage and the residual current at a point of common coupling (“PCC”). The method then includes monitoring the resistive and reactive parts of the line impedance. For example, the method can monitor the line impedance and report a broken PE conductor or a high PE resistance, beyond a given threshold where safety becomes a concern.

A broadband-capable current / voltage sensing-based VSWR resilient true power / impedance detector and method are disclosed that can be used for single-ended interfaces of individual phased array elements of a phased array antenna, e.g., large-scaled integrated phased-arrays. The true power and impedance detectors, as Built-in-Self-Test (BiST or BIST) circuitries, may each employ an in situ load invariant power and impedance sensor to provide true measurements of power and impedance that can be used to detect and / or monitor for VSWR variations and / or variations in the antenna driving impedance due to antenna element coupling and / or other effects. The measured power and impedance output(s) of each BIST circuitry can then be used to adjust or drive respective passive or active tuning circuitry, e.g., in the power amplifier or other front-end circuitries of the phased array antenna, for performance recovery (or optimization) of a respective array element.

In leakage detecting device (10) that detects an electric leakage from a high-voltage unit in which power storage unit (20) and a load are connected by a power supply line in a state of being insulated from an earth, Y capacitor (CY) is connected between the earth and a current path between power storage unit (20) and the load. Drive unit (11) of leakage detecting device (10) outputs a rectangular wave voltage to the current path between power storage unit (20) and the load via driving coupling capacitor (Cd1) to charge or discharge Y capacitor (CY). Leakage detector (12) determines presence or absence of the electric leakage between the current path and the earth according to a time transition in which the voltage at the measurement point of the current path changed according to charging or discharging of Y capacitor (CY) converges to an original voltage.

The invention relates to a method and a device for monitoring the insulation resistance of a traction network (1), wherein the traction network (1) comprises a high-voltage battery (2), a DC / DC converter (3), an intermediate circuit capacitor (C), and an inverter (4), wherein the device comprises a first insulation resistor (R1) with a switching element (S1) and a second insulation resistor (R2) in series with a second switching element (S2), wherein the device has a voltage measuring device (V1, V2) assigned to the first insulation resistor (R1) and the second insulation resistor (R2), respectively, wherein the device further comprises a control and evaluation circuit (6) that controls the switching elements (S1, S2) and reads the voltage values, wherein the control and evaluation circuit (6) is configured such thatat least one measurement with the first switching element (S1) closed and the second switching element (S2) open, and at least one measurement with the second switching element (S2) closed and the first switching element (S1) open, whereby a virtual equivalent circuit diagram for the high-voltage battery (2) is established.

A method for measuring an earth resistance in a battery charging system connected to the power grid includes, for each measurement cycle, injecting a first, alternating current, signal between a first, neutral node and a second, earth node, detecting a first voltage signal representing an electrical potential difference between the first and second node, calculating an earth resistance value as a function of the first voltage signal. Further, injecting between the first, neutral node and the second, earth node an information signal representing the calculated earth resistance value. Before the injecting the first alternating current signal: detecting one or more information signals generated by further battery charging systems connected to the power grid; determining the earth resistance value based on the information content of the received information signals; proceeding with steps a) to c) if a number of information signals lower than the pre-set limit value is detected.

The invention discloses a power grid impedance identification method based on model reference self-adaption, and belongs to the technical field of electrical engineering. The method comprises the steps of establishing a reference model, and adopting integral control to iterate the reference model. A three-phase grid-connected current estimation value is obtained by establishing a reference model, the three-phase grid-connected current estimation value tracks the sampled three-phase grid-connected current through integral control, and power grid impedance parameters in the reference model are iterated. And when the three-phase grid-connected current estimation value is consistent with the sampled three-phase grid-connected current, the iterative power grid impedance parameter in the reference model is the final power grid impedance identification value. According to the method, active injection harmonic disturbance is not needed, a complex signal processing method is not needed, grid-connected current control is not affected on the basis, and the power grid impedance identification result is accurate.

A measurement apparatus includes a measurement unit 2 having any two or more of a first measurement unit 11 configured to measure, by a first configuration, a wireway electricity related value of a wireway branched from a wireway to be measured to which a star-connected three-phase AC power source is connected, a second measurement unit 21 configured to measure, by a second configuration, a wireway electricity related value of a wireway branched from a wireway to be measured to which a star-connected three-phase AC power source is connected, a third measurement unit 31 configured to measure, by a third configuration, a wireway electricity related value of a wireway branched from a wireway to be measured to which a delta-connected three-phase AC power source is connected, and a fourth measurement unit 41 configured to measure, by a fourth configuration, a wireway electricity related value of a wireway branched from a wireway to be measured to which a delta-connected three-phase AC power source is connected, and a selection processor 51 configured to select any one of the measurement units in the measurement unit 2.

A method for determining the conductivity of an electrical conductor between a first system component and a second system component, the method steps determining a first voltage value and a second voltage value at the first or second system component for a given current intensity value; determining a first differential value between a reference voltage value at the first system component and the first voltage value; determining a second differential value between a reference voltage value at the first system component and the second voltage value; identifying a transition resistance as a quotient from the second differential value and the current intensity value when a difference between the first and second differential values reaches a predetermined threshold value; and adjusting the first and / or second system component from a first operating state into a second operating state and / or emitting at least one signal by means of a display device on the first and / or second system component when the transition resistance reaches a predetermined threshold value.

The invention relates to a method and an insulation monitoring device for insulation monitoring with network balancing in an ungrounded DC network, comprising a measurement of line-to-ground voltages using voltage measuring devices, a conductor-selective calculation of insulation resistances, and the compensation of voltage asymmetry between the line-to-ground voltages by means of a control loop. The invention includes a combination of insulation monitoring function and network balancing based on a digital control loop with the degree of asymmetry (asymmetry factor) as the controlled variable. The voltage asymmetry is continuously compensated by suitable evaluation of a (voltage) control curve by means of a controller, and the required resistance setting value is determined as the manipulated variable for one of the potentiometers.

An impedance measurement method and apparatus for a converter, an electronic device, and a medium are applied to the field of converter data calculation and processing. A positive-sequence current disturbance and a positive-sequence voltage disturbance are respectively superimposed at a current value sampling position and a voltage value sampling position of the converter, to obtain a first disturbance current value, a first disturbance voltage value, a second disturbance current value, and a second disturbance voltage value; a first to-be-measured impedance value and a transfer function are determined based on the obtained values; further, a second to-be-measured impedance value and an initial impedance value are determined based on the first to-be-measured impedance value, the transfer function, a filter equivalent impedance value, and relevant parameters of the converter, and a final target impedance value of the converter is determined based on the initial impedance value and a decoupling coefficient.

The invention discloses a through hole test structure, a test method and an integrated circuit, and belongs to the technical field of semiconductors, the through hole test structure at least comprises a bottom metal layer, a top metal layer and a middle metal layer; the through hole layer is connected with the two metal layers, the through hole layer comprises a first type of connecting structure and a second type of connecting structure, the first type of connecting structure comprises a first number of through holes, the second type of connecting structure comprises a second number of through holes, and the second number is greater than the first number; wherein the bottom through hole layer or the top through hole layer comprises at least one first type of connecting structure, and at least one first type of connecting structure is additionally arranged at any position of the current through hole layer except the position of the first type of connecting structure of the upper layer in the lamination direction of the through hole layers. Through the through hole test structure, the test method and the integrated circuit provided by the invention, the accuracy of abnormal detection of the through hole can be improved.

A method and insulation monitoring arrangement for insulation monitoring of an electric installation operated using a supply direct voltage and has a first insulation resistance between the positive active conductor and ground and a second insulation resistance between the negative active conductor and ground as well as a functional grounding between the negative active conductor and ground by a ground resistance. The method involves measuring a ground current, which flows in the path of the functional grounding, by means of a DC measuring device; measuring the supply direct voltage by means of a voltage measuring device; computing the first insulation resistance from the supply direct voltage divided by the ground current by means of a computing unit; the condition is valid during operation of the electric installation that the second insulation resistance being at least 100 times greater than the ground resistance.

An example isolation measurement circuit includes a first switch connecting a first isolation resistor to a terminal of a measurement resistor, the first isolation resistor also connecting to a positive bus of a power distribution system. The isolation measurement circuit also includes a second switch connecting a second isolation resistor to the terminal of the measurement resistor, the second isolation resistor also connecting to a negative bus of the power distribution system. The isolation measurement circuit also includes a pulse generator that connects the measurement resistor to chassis ground.

The invention relates to the technical field of photovoltaic inverter grid connection, and discloses a multi-path photovoltaic access ground insulation impedance fault positioning method, device and equipment, the output end of a multi-path photovoltaic is connected with a photovoltaic inverter, the method comprises the following steps: after the photovoltaic inverter is connected to the grid, collecting the leakage current and photovoltaic input voltage of the output end of the multi-path photovoltaic; extracting a leakage current direct current component from the leakage current; and traversing the photovoltaic input voltage of each path of photovoltaic, positioning the positive electrode or the negative electrode of the corresponding path of photovoltaic with abnormal insulation resistance to ground according to the magnitude change or the positive and negative of the leakage current in the traversing process, and detecting the insulation resistance to ground of multiple paths of photovoltaic on line based on the photovoltaic input voltage, the positive electrode or the negative electrode of the corresponding path of photovoltaic and the direct current component of the leakage current. According to the method, the purpose of accurately positioning the impedance abnormal photovoltaic string through multi-path photovoltaic input is achieved, and the problems that online ground insulation impedance cannot be achieved, and fault positioning cannot be conducted on the insulation impedance abnormal condition are solved.

The invention provides a relay protection method applied to an alternating-current line of a photovoltaic power generation flexible direct-current sending-out system, relates to the technical field of relay protection of a power system, and aims to solve the problems of limitation of wave head feature loss, high sampling rate, large communication traffic and the like of an existing traveling wave protection method. The relay protection method comprises the following steps: acquiring voltages and currents of two detection points, and determining a current value of a front traveling wave and a current value of a reverse traveling wave of the detection points based on the voltages, the currents and wave impedance of the detection points; determining the current flowing time tau, determining the traveling wave difference of the detection points based on the current values of the reverse traveling waves of the two detection points, the set frequency and the flowing time tau, and finally determining whether the AC line has a fault based on the sum of the traveling wave difference of the detection points in the detection time interval. According to the relay protection method, the traveling wave calculation result of the whole process is used for fault judgment, the protection reliability is high, and the precision is higher.

The invention relates to a monitoring device (14) for detecting a leakage current in a surge protection device (12). The monitoring device (14) has a connection (15) for series connection with the surge protection device (12). The monitoring device (14) has a short-circuit current-quenching and / or overvoltage-switching component (20). The monitoring device (14) has a detection circuit (22) connected in parallel to the short-circuit current-quenching and / or overvoltage-switching component (20). The detection circuit (22) comprises at least one measuring capacitor (24) with a measuring capacitance, which is connected in series with the surge protection device (12). The detection circuit (22) comprises measuring electronics (26) configured to detect a leakage current-relevant parameter. Furthermore, an assembly (16) and a method for detecting a leakage current in an overvoltage protection device (12) are described.