533results about "Impedence measurements" patented technology

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 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.

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.

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.

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.

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 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.

An energy storage system and an insulation impedance detection method for an energy storage system. The energy storage system includes a plurality of energy storage converters, a plurality of energy storage units, one first insulation impedance detection apparatus, a plurality of second insulation impedance detection apparatuses, and a controller. The energy storage units are connected to direct current ends of the energy storage converters, and are correspondingly connected to the second insulation impedance detection apparatuses, and a parallel connection point of alternating current ends of the plurality of energy storage converters is connected to the first insulation impedance detection apparatus. When a first insulation impedance is abnormal, the controller controls the plurality of second insulation impedance detection apparatuses to detect corresponding second insulation impedances, and sends an alarm signal if there is an abnormal second insulation impedance.

An apparatus for providing radio frequency (RF) power includes a load having a process chamber, a RF power generator configured to provide the RF power through a cable electrically connected to the load, and a reflected power controller configured to detect reflected power from the load in a delivery mode and configured to control the RF power according to the reflected power that was detected.

This application provides a power system and a method for detecting a ground impedance. The power system includes a converter and a short-circuit detection apparatus The converter includes a positive bus capacitor and a negative bus capacitor that are connected in series, and a series connection point between the two bus capacitors is a neutral point. The short-circuit detection apparatus is connected to an equivalent neutral point. A ground potential difference of the equivalent neutral point is positively correlated with a ground potential difference of the neutral point. The equivalent neutral point includes a connection end of three phases of output ends of the converter. The short-circuit detection apparatus outputs a first voltage value and a second voltage value to the equivalent neutral point, and obtains a first current value and a second current value of the short-circuit detection apparatus when the first voltage value and the second voltage value are output. The short-circuit detection apparatus obtains a ground impedance of the power system based on the first voltage value, the second voltage value, the first current value, and the second current value, and reports or sends ground impedance abnormality fault information when the ground impedance is less than a specified threshold. According to this application, ground impedances of an alternating current side and a direct current side of the power system can be detected, and a ground impedance detection range is wide.

Electrical storage system with: an electrical storage device (10); a load (20); a line (PL) configured to connect the electrical storage device (10) and the load (20); a relay (SMR-G) that is provided in the line (PL); a capacitor (C11) which has one end connected to the electrical storage device (10) and the other end connected to a ground; a voltage sensor (21) configured to detect a voltage value of the capacitor (C11); a first insulation resistance (RB) which is set up between the electrical storage device (10) and the ground; a second insulation resistor (RL) which is installed between the load (20) and the ground; a first current path (L1) which includes the first insulation resistance (RB); a second current path (L2) comprising the conductor (PL) and the second insulation resistance (RL); and a control unit (50) that is configured to (a) Controlling ON and OFF of the relay (SMR-G), and (b) Determine that the relay (SMR-G) is blocked in an ON state if the voltage value is substantially equal to a second voltage value in a case where control to turn off the relay (SMR-G) is carried out, where a first resistance value is higher than a second resistance value, the second voltage value is higher than a first voltage value, the first resistance value is a resistance value of the first insulation resistance (RB), the second resistance value is a resistance value of the second insulation resistance (RL), the first voltage value is a voltage value when a discharge current of the electrical storage device (10) flows to the capacitor (C11) in the first current path (L1), the second voltage value is a voltage value when the discharge current of the electrical storage device (10) flows to the capacitor (C11) in the second current path (L2).

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

The invention discloses a power supply system impedance and short-circuit current detection method and system, and relates to the field of electrical variable measurement, in the method, node voltage and current characteristic quantities are calculated based on collected data, a voltage drop equation is established, line impedance is calculated, and impedance correction is performed by considering temperature influence. Obtaining parameters of the transformation equipment, determining impedance of the transformation equipment and calculating load equivalent impedance. A short-circuit fault is identified by monitoring a current change rate, a voltage amplitude and a high-frequency characteristic in real time and combining a judgment threshold value set by historical data. And after the occurrence of the short-circuit fault is judged, the fundamental wave short-circuit current is calculated by using the corrected impedances and a symmetric component method, and the peak value of the short-circuit current is finally obtained by combining the impact coefficient calculated by the ratio of the real-time reactance to the resistance of the system. The method and the device are used for improving the accuracy of a short-circuit current calculation result in an environment with dramatic temperature change, so that the reliability of relay protection setting is improved.

When balancing cells in battery packs, the voltage induced by the balancing current across the parasitic wire resistance distorts the measured cell voltage, leading to inaccurate cell state estimation. A method and battery management system to extract a parasitic resistance of battery connection wires connecting a cell of a battery to a cell balancing circuit is disclosed. The parasitic wire resistances for a battery pack are extracted through the coordinated operation of a pack-level current source and cell-level balancing circuit. A voltage drop is imposed and measured across the parasitic resistances while maintaining zero current in the immediate battery cell. Maintaining zero current in the immediate battery cell avoids possible extraction error resulting from voltage drop across the battery cell impedance due to battery cell current flow.

An inverter and an insulation impedance detection method for the inverter are provided. The insulation impedance detection method includes connecting a bridge arm midpoint of one phase at an AC side of an inverter circuit in the inverter to one electrode of the DC bus, and determining a relationship between a neutral-to-ground voltage at the AC side of the inverter circuit and a half-bus acquisition voltage of the DC bus under a present connection condition; and calculating the half-bus voltage before and after the controllable switch is turned on based on a sampled value of the neutral-to-ground voltage at the AC side and the relationship to obtain calculated values; and calculating an insulation impedance at the DC side of the inverter to ground based on the calculated values, equivalent impedances of the DC bus to the ground before and after the controllable switch is turned on.

A display apparatus and a test method therefor. The display apparatus comprises a display substrate (11), and an integrated circuit (12) and a flexible circuit board (13) separately bound and connected to the display substrate (11). The display substrate (11) comprises multiple first substrate pads (111A) and multiple second substrate pads (111B). The integrated circuit comprises a test signal end and multiple first connection pads (121). The display substrate (11) or the integrated circuit (12) comprises a first switch unit (S1) and a second switch unit (S2). At least two first connection pads (121) are electrically connected to the test signal end by means of the first switch unit (S1), and at least two second substrate pads (111B) are electrically connected to the test signal end by means of the second switch unit (S2). The integrated circuit (12) detects the status of the binding connection between the integrated circuit (12) and the display substrate (11), or between the flexible circuit board (13) and the display substrate (11), by means of controlling the connection and disconnection of the first switch unit (S1) and the second switch unit (S2), respectively, such that an impedance test signal of the test signal end passes through test pathways in which the first switch unit (S1) and the second switch unit (S2) are located.

A single-torus ohmmeter for measuring a loop impedance Zx, includes a single transformer having a primary winding of Np coils and a secondary winding of a single coil forming the measurement loop, in which, to compensate for a stray induction produced by an AC leakage current circulating in the measurement loop without canceling a measurement current Ip generating an alternating induction of constant average value for the measurement of the loop impedance Zx, the transformer includes a second secondary winding of Na coils whose output voltage Ub representative of the AC leakage current is delivered to a processing module providing a voltage intended to be added to an alternating measurement voltage Vp in an adder delivering the current to be injected into the primary winding after passage through a voltage-current converter.

The invention relates to an impedance modeling method and device and computer equipment. Comprising the steps that disturbance voltage is injected to the alternating current side of a main circuit, a first relation between a modulation small signal and an alternating current small signal is obtained through alternating current control topology, the disturbance voltage and a phase angle small signal are correlated through a phase-locked loop, and a second relation between the modulation small signal and an alternating voltage small signal is determined; injecting disturbance voltage to the direct current side of the main circuit, and determining a third relationship between the modulation small signal and the alternating current small signal and a fourth relationship between the direct current small signals based on the alternating current control topology and the direct current control topology; and finally, impedance modeling is carried out in combination with a frequency small-signal model, so that self-impedance and coupling impedance characteristics of an alternating current side and a direct current side can be accurately reflected, and a basis is provided for analyzing system stability and optimizing a control strategy.

Methods of powering a radio that is mounted on a tower of a cellular base station are provided in which a direct current (“DC”) power signal is provided to the radio over a power cable and a voltage level of the output of the power supply is adjusted so as to provide a substantially constant voltage at a first end of the power cable that is remote from the power supply. Related cellular base stations and programmable power supplies are also provided.

The invention relates to the technical field of impedance measurement, and provides a grid-connected converter broadband positive and negative sequence impedance parameter acquisition method and system, and the method comprises the steps: building a grid-connected converter simulation model; a positive and negative sequence harmonic disturbance small signal injection unit, an auxiliary phase-locked loop unit, a current signal auxiliary processing unit and an RLC circuit equivalent unit are added in a grid-connected converter simulation model; the positive and negative sequence harmonic disturbance small signal injection unit superposes harmonic disturbance with preset frequency and phase sequence at a power grid power frequency three-phase voltage source port; the auxiliary phase-locked loop unit obtains a phase angle of a power frequency three-phase voltage source of the power grid; the current signal auxiliary processing unit processes the grid-connected point current signal; and the RLC circuit equivalent unit obtains the impedance parameter of the grid-connected converter by measuring the loop current effective value and the phase angle. Positive and negative sequence impedance parameters with clear physical significance can be obtained, and the method has the advantages of being simple in algorithm, convenient to use, accurate in result, high in impedance data obtaining speed and the like.

The invention relates to the technical field of fire sensing, and discloses an electrical fire state sensing system and method for a low-voltage distribution line, and the method comprises the steps: setting a first monitoring point at a wire inlet end of a distribution loop, setting a second monitoring point at a load access end, setting a differential protection region, and calculating a first on-resistance; performing moving average processing on the first on-resistance to obtain a second on-resistance, calculating a first reference on-resistance according to the second on-resistance, and performing temperature correction on the first reference on-resistance to obtain a second reference on-resistance; according to the method, the on-resistance deviation rate, the on-resistance growth rate and the on-resistance fluctuation coefficient are calculated, whether the on-resistance is in an early warning state, an alarm state or a dangerous state is judged, the on-resistance of the section is calculated in real time according to the ratio of the differential voltage drop to the current, and the technical problem that a fault section cannot be accurately positioned through traditional whole-line monitoring is solved.

The invention relates to a method for signaling a battery fault (BF) of a battery (14) for a motor vehicle (10) by a control device (12, 12'). The control device (12, 12') signals the battery fault (BF) as a function of an insulation fault signal (IS) provided to the control device (12, 12') by an insulation resistance measuring device (16), which relates to a general, non-localized insulation fault (FI) of an on-board electrical system comprising the battery (14), and as a function of a device signal (E; E1, E2, E3) provided to the control device (12, 12') by a device (18, S) comprising at least one battery sensor (S).

A DC power system (1a, 1b, 1c, 1d, 1e, 1f) and an insulation resistance monitor device (14) thereof are provided. The DC power system (1a, 1b, 1c, 1d, 1e, 1f) includes positive, neutral and negative lines (11, 12, 13), a protective earthing terminal (PE) and a grounding resistor (Rgnd). The grounding resistor (Rgnd) is electrically connected between the neutral line (12) and the protective earthing terminal (PE). The insulation resistance monitor device (14) includes a first resistor (R1), a first sensing resistor (Rs) and a first detection circuit (141). The first resistor (R1) is coupled to the positive or negative line (11, 13). The first sensing resistor (R1) is coupled between a second terminal of the first resistor (R1) and the protective earthing terminal (PE). The first detection circuit (141) is electrically connected to the first sensing resistor (Rs), and is configured to measure a sensing voltage across the first sensing resistor (Rs) and detect whether an insulation resistance between the protective earthing terminal (PE) and any of the positive, neutral and negative lines (11, 12, 13) is abnormal according to the sensing voltage.

Techniques are provided for automatically determining when voltage and current levels occur when a DC input of a radio is drawing substantially constant power through electrical conductors from a DC voltage converter. Such voltage and current level occurring when such power draw is substantially constant can then be used to determine a resistance of the electrical conductors. Subsequently, the resistance can be used to vary an output voltage of the DC voltage converter when the power draw, and thus the direct current drawn through the electrical conductors, varies.

A method for driving an electro-optic display including an electro-optic material disposed between a common electrode and a backplane. The backplane includes an array of pixel electrodes, each coupled to a transistor. A display controller applies a waveform to the pixel electrodes. The method includes applying a first measurement waveform to a first portion of the pixel electrodes. During each frame of the first measurement waveform, an identical time-dependent voltage is applied to each pixel electrode of the first portion of the pixel electrodes. The method includes determining an impedance of the electro-optic material proximate the first portion of the pixel electrodes based on measurements of the current flowing through a current measurement circuit and the time-dependent voltage applied to each pixel electrode during the first measurement waveform, and selecting a drive waveform based on the impedance of the electro-optic material proximate the first portion of the pixel electrodes.

The present disclosure relates to a method for determining a fault section in a series-compensated transmission line, the method comprising: obtaining impedance parameters of the transmission line; obtaining a first voltage and a first current at a first bus; obtaining a second voltage and a second current at a second bus; obtaining a current through an series compensator in a direction towards the first bus, wherein the series compensator is arranged between the first bus and the second bus; and determining a fault section based on: the impedance parameters, the first voltage and the first current, the second voltage and the second current, and the current through the series compensator.