144results about "Direction of current indication" patented technology

The disclosure deals with system and methodology subject matter for source-agnostic time-domain directional relays for power grid applications, including system and methodology subject matter for Inverter based resources (IBRs) which are instrumental in facilitating the integration of renewable energy resources and storage into the power grid. IBRs exhibit unique fault characteristics significantly different from synchronous generators (SGs), dictated by their proprietary controls, posing challenges for the reliable operation of directional relays designed in phasor domain. This disclosure relates to a source-agnostic directional relay formulated in time domain, thus making any polarization unnecessary. It is immune to decaying dc offset and pre-fault currents, and applicable to transmission and distribution feeders with up to 100% IBR penetration. Its performance is superior to a numerical commercial relay in a hardware in the loop setup, and its chosen sampling rate of 24 or more samples per cycle (spc) makes it readily implementable in commercial numerical relays.

There is provided a diverted neutral current (DNC) detector 100, an apparatus 200, a method 400, and a computer program 206. The DNC detector 100 comprises a sensor arrangement CTP, CTN, CTE, VS. The DNC detector 100 further comprises circuitry 201 configured to determine whether a condition is satisfied in dependence on information from the current sensor arrangement, and output one or more signals in dependence on satisfaction of the condition.

A power semiconductor circuit includes: a power semiconductor element having a gate electrode configured to actuate the power semiconductor element, a collector electrode, and an emitter electrode electrically connected to a first emitter terminal; and a temperature sensor having a first measurement point with a measurement terminal and a second measurement point electrically connected to the emitter electrode, so that a voltage which drops over the temperature sensor is measurable between the measurement terminal and the first emitter terminal for the temperature measurement. Corresponding methods for determining a temperature of a power semiconductor element and for determining a sign of a load current in a bridge circuit are also described.

A semiconductor device includes a first and a second output transistor on a high and a low side respectively, a first terminal connected to the connection node between the first and second output transistors, and a second terminal configured to be connected via a bootstrap capacitor to the first terminal. The first output transistor is driven based on a voltage between the first and second terminals. A switching circuit is provided between a terminal fed with a predetermined control supply voltage and the second terminal. The switching circuit includes a first and a second switching element, which are N-channel MOSFETs connected in series. According to the voltage at the first terminal, the first and second switching elements are turned on or off.

The utility model provides a circuit for assisting a locked-rotor current test of an electric vehicle controller, a circuit board and a controller, in the circuit, first normally open ends of a first switch, a second switch and a third switch are respectively used for being electrically connected with a first phase input end, a second phase input end and a third phase input end of a motor Hall; the second normally-open ends of the first switch, the second switch and the third switch are electrically connected with the first LED lamp, the second LED lamp and the third LED lamp respectively; the first normally-open ends of the fourth switch, the fifth switch and the sixth switch are electrically connected with the first phase input end, the second phase input end and the third phase input end of a motor Hall respectively, and the second normally-open ends of the fourth switch, the fifth switch and the sixth switch are electrically connected with a fourth LED lamp, a fifth LED lamp and a sixth LED lamp respectively. When the locked-rotor current direction needs to be switched, the short-circuit states of the three input ends of the motor Hall can be adjusted only by adjusting the states of the corresponding switches, and the short-circuit states can be displayed through the corresponding LED lamps, so that the operation convenience of switching the locked-rotor current direction through short-circuit of the motor Hall is improved.

A flux switch system is disclosed. The system (50) includes an input stage (52) configured to provide an interrogation pulse. The system also includes a plurality of flux loops (62, 64) configured to receive an input current (IIN). Each of the flux loops includes a Josephson junction (J1, J2) configured to trigger to generate an output pulse in response to a first polarity of the input current and to not trigger to generate no output pulse in response to a second polarity of the input current opposite the first polarity. The system further includes an output stage (54) configured to propagate the output pulse to an output (INTout) of the flux switch system.

The application discloses a voltage acquisition circuit, a bipolar direct-current power supply and a voltage acquisition method. A voltage difference between a near-end voltage and a far-end voltage is calculated by a subtracter. First, second and third switch switching units combine the positive and negative states of a power supply output voltage to switch the connection relationship between the voltage difference output by a positive voltage compensation voltage unit, a negative voltage compensation voltage unit and the subtracter and two input ends of a comparator. When a positive voltage is output, the positive voltage compensation voltage unit is connected to the inverting input end of the comparator, and the output end of the subtracter is connected to the non-inverting input end of the comparator; when a negative voltage is output by the power supply, the negative voltage compensation voltage unit is connected to the non-inverting input end of the comparator, and the output end of the subtracter is connected to the inverting input end of the comparator. A control unit determines whether far-end sensing sampling is normal according to the high and low levels of an abnormal comparison voltage output by the comparator. The application can identify the situations of disconnection and reverse connection when the bipolar direct-current power supply outputs a negative voltage.

For a DC-overcurrent detector (1) comprising an electric line (2), a first current sensor (3), a current flow direction sensor (4) and a comparator unit (5) it is suggested, that the detector (1) further comprises a threshold criterion unit (6), with an input of the threshold criterion unit (6) being connected to the current flow direction sensor (4) for receiving an actual current flow direction, and with an output of the threshold criterion unit (6) being connected to the comparator unit (5), proving the comparator unit (5) with the threshold criterion, and that the threshold criterion unit (6) is adapted to determine a first threshold criterion in case the actual current flows in the first direction (14), and a second threshold criterion in case the actual current flows in the second direction (15).

A contactless current sensing system and method for high power density power electronics systems are provided. The contactless current sensing system is a two current sensor system in which two current sensors having substantially the same sensitivity are positioned on opposite sides of a current-carrying conductor.

The present invention discloses a PV panel reverse connection detection device, including a first boost circuit for reverse connection detection of a first PV battery string, the first boost circuit including a first voltage divider resistor, a first detection resistor, a first capacitor, a first inductor, a first diode, a busbar electrolytic capacitor and a first IGBT power element. A PV panel reverse connection detection method is also provided, which is suitable for detection using a PV panel reverse connection detection device. By connecting a detection resistor in parallel in the first boost circuit and adding voltage acquisition and voltage comparison at the input stage, it is determined whether the first PV battery string is reverse connected, thereby avoiding the problem of power generation loss caused by the reverse connection of the first PV battery string, and there is no need to configure a current sensor for the first PV battery string in the first boost circuit separately, further reducing the production cost of photovoltaic power generation equipment.

This application relates to the field of generator testing technology, and particularly to a method, apparatus, and equipment for determining the power direction of a generator's current transformer. The method includes: short-circuiting the target side of a transformer to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected to the loop; injecting current into the short-circuit closed loop through a zero-start current from the generator until the generator terminal current rises to a first target current; using the waveform recorder to acquire the secondary voltage at the generator terminals and the secondary current of the current transformer, calculating the actual reactive power at the generator terminals based on the secondary voltage and secondary current; and determining the power direction of the generator's current transformer based on the reference reactive power and the actual reactive power at the generator terminals. This solves the problem that the power direction of the generator's current transformer secondary current and terminal secondary voltage, as well as the limitation of impedance components, can only be tested and verified after grid connection.

The present invention relates to a fluxgate type leakage current detection device, characterized by including: an oscillator unit that generates a pulse current having a predetermined frequency; at least one first core wound with at least one first coil having one end connected to the oscillator unit and magnetized by the pulse current; a second core wound with a second coil having one end grounded; and a core unit that supplies a third coil wound around the first core and the second core and supplied with a compensation current; and a control unit that determines the frequency of the pulse current in accordance with at least one feature of the at least one first core, filters out a frequency component from a voltage signal of a current induced in the at least one first core, detects a DC component leakage current of a conductor to be measured, and supplies a reverse current corresponding to the detected DC component leakage current to the third coil as the compensation current.

Disclosed in the present application are a load control circuit, a chip, a communication circuit and an interactive control method. The load control circuit comprises a rectifier bridge circuit, a modulation circuit, an energy control module, and a first controller, wherein the rectifier bridge circuit is connected to the modulation circuit; the rectifier bridge circuit is connected to the energy control module; the first controller is connected to both the modulation circuit and the energy control module; the rectifier bridge circuit is used for rectifying an input signal and outputting a rectification result; an input signal port in the rectifier bridge circuit is used for connecting in parallel to a load element external to the load control circuit; the first controller is used for causing a current change in the rectifier bridge circuit by means of controlling the modulation circuit, so as to drive a current change in the load element to perform modulation; and the energy control module is used for charging, by means of the rectification result, a capacitor externally connected to the load control circuit, and for gating the capacitor externally connected to the load control circuit to supply power to the modulation circuit.

According to the voltage calibration method for judging the LLC charging and discharging direction, the battery voltage sampling value and the bus voltage sampling value are calibrated, and even under the conditions that the turn ratios of transformers of all products are slightly different and the actual bus voltage value is difficult to measure, the battery voltage sampling value and the bus voltage sampling value are calibrated; and the charging and discharging directions can be accurately judged according to the calibrated battery voltage sampling value and the calibrated bus voltage sampling value, so that the circuit cost is saved and the calibration difficulty is reduced.

The invention discloses a multi-channel device for rapidly measuring extra-small unit current. The multi-channel device is an integral multi-channel measuring device composed of a plurality of single-channel measuring modules. The single-channel measurement module comprises a gear switching module, a sampling module, an absolute value module, an ADC module, an MCU module and a human-computer interface module. The gear switching module is connected with a measured load. Positive and negative currents can be rapidly measured, and the current value can be extremely small. The main aspect of the device is characterized in that a floating ground technology and an absolute value circuit are adopted, other devices can rapidly realize filtering rectification, and a current value can be rapidly measured.

There is provided mechanisms for determining direction of an EF in a feeder of a high impedance grounded power system. A method is performed by an IED. The method comprises obtaining a measure of a first order harmonic active current component derived from residual voltage and current of the feeder as valid for when the EF occurred in the feeder. The method comprises obtaining a measure of a higher than first order harmonic reactive current component derived from residual voltage and current of the feeder as valid for when the EF occurred in the feeder. The method comprises determining the direction of the EF in the feeder based on a combination of the first order harmonic active current component and the higher than first order harmonic reactive current component.

The present application relates to a control method, an apparatus, a computer device and a storage medium. The method comprises: acquiring a test current of a valve tower test circuit; and on the basis of the test current and a preset reference current, determining a modulation wave for each sub-module of a target valve tower in the valve tower test circuit, so as to control each sub-module in the valve tower test circuit on the basis of the modulation wave. By using the method, each sub-module in a valve tower test circuit can be controlled during a test.

The application provides a kind of airborne high-voltage direct current system protection method and device, the system includes DC bus, protection controller and the distribution function unit connected between DC bus and each function unit branch, distribution function unit at least includes series connection's explosive fuse, contactor and current sensor;Including the following steps: each function unit branch is defined as power supply branch or load branch, and forward action logic and reverse action logic based on current flow direction are set for power supply branch and load branch respectively;System operation, current amplitude and direction signal flowing through each function unit branch are collected in real time using current sensor, and current amplitude and direction signal are transmitted to protection controller;Protection controller selects corresponding action logic according to the direction signal detected currently, and compares current amplitude with action threshold in selected action logic, when current amplitude exceeds action threshold, explosive fuse or contactor is triggered to execute protection action.

A safety module for an inverter of a motor vehicle. The inverter including at least two power circuits. The safety module including a control unit and at least two safety switches, each safety switch being associated with a power circuit and being connected between the power circuit and a point referred to as the “measurement” point. The control unit being capable of controlling each safety switch and being configured to detect a closing malfunction of a safety switch if: a) a closing command has been sent to the safety switch, the other safety switches being open, b) and the voltage at the measurement point is negative.

A multi-path current difference detection device includes an induction component and a determination unit. The induction component induces a plurality of currents flowing through a plurality of paths, and calculates a net current value of a plurality of current values of the plurality of currents. The determination unit receives a current signal corresponding to the net current value, and provides a detection signal when determining that the current signal is greater than or equal to a current threshold.

An electrical apparatus (figure 1) forms part of an AC power supply network and comprises one or more measurement devices (22, figure 2) to measure a voltage and current on a conductor (12, figure 1) forming part of a power line of the AC network. A control unit receives current and voltage measurements from the measurement device. The controller determines the presence of a short circuit condition at time T1 and identifies a first voltage measurement recorded at time T2, prior to onset of the short circuit. Based on the first voltage measurement, a phase of the voltage signal at a first time T1 during which the short circuit condition is occurring can be determined. From the determined phase of the voltage signal and a measured phase of the current signal at the first time, a phase angle between the current signal and the voltage signal can be calculated, even though the voltage at this time cannot accurately be recorded.

The application discloses a kind of open-winding photovoltaic energy storage converter system fault diagnosis method, device, equipment and storage medium, it is related to power electronic converter fault diagnosis technical field, the method comprises: obtaining the photovoltaic side DC bus current, energy storage side DC bus current and three-phase AC output current of open-winding photovoltaic energy storage converter system;According to three-phase AC output current, photovoltaic side DC bus current, energy storage side DC bus current obtains the current residual of photovoltaic side fault phase and the current residual of energy storage side fault phase;The current residual of photovoltaic side fault phase and the current residual of energy storage side fault phase are processed, and first diagnostic variable and second diagnostic variable are obtained;Detect the current flow direction of fault phase in open-winding photovoltaic energy storage converter system;According to the current flow direction of fault phase, first diagnostic variable and second diagnostic variable, determine fault location.The method can realize accurate fault positioning of open-winding photovoltaic energy storage converter system.

The invention relates to the field of power grid monitoring, and discloses a fault studying and judging method, device and system for a self-adaptive standing book and an adaptive pole-mounted switch. The method comprises the following steps: determining a first transient zero-sequence current frequency and a second transient zero-sequence current frequency corresponding to each pole-mounted switch point, and determining machine account information corresponding to each pole-mounted switch point according to a current frequency ratio between the first transient zero-sequence current frequency and the second transient zero-sequence current frequency; then determining the polarity of the transient zero-sequence current between the switch point positions on every two adjacent columns; determining a power supply direction between every two adjacent pole switch points according to the polarity of the transient zero sequence current; performing fault study and judgment on the line according to the standing book information and the power supply direction; therefore, the self-adaptive standing book identification and the power supply direction are used as preconditions of fault research and judgment, the accuracy of fault research and judgment can be improved, and fault misjudgment and missed judgment are reduced.

To provide a power monitoring device and a monitoring method thereof.SOLUTION: A power monitoring device includes a power detection module and a processor. The power detection module converts a forward power into a forward signal, and converts a reverse power into a reverse signal. The processor is configured to determine whether the forward signal and the reverse signal meet a first judgment condition at a first time to generate a first result, and to determine whether the forward signal and the reverse signal meet a second judgment condition at a second time to generate a second result. The processor determines whether to send a warning signal based on the first result and the second result.SELECTED DRAWING: Figure 1

The invention discloses a three-phase circuit lightning stroke identification method and device, relates to the technical field of power system positioning, and aims to accurately judge the lightning stroke type and the lightning stroke position, conveniently identify the line accident reason and quickly position the line fault caused by the lightning stroke. The method comprises the following steps: fitting a relationship between a lightning peak value on a line and a transmission distance according to a finite difference time domain method; a transient magnetic field generated by lightning stroke is induced through a PCB differential ring, and induced electromotive forces generated at the two ends of the transient magnetic field are sampled; when the induced electromotive force is greater than a set threshold value, recording current waveform data of a three-phase line; and judging an output lightning stroke type according to the current waveform data and whether the polarities of the three-phase current head waves are the same or not, and judging a lightning stroke position in combination with a relationship between a lightning peak value and a transmission distance. The lightning stroke type and the lightning stroke position can be accurately judged, and line accident reasons can be conveniently identified and line faults caused by lightning stroke can be rapidly positioned.

A three-phase three-wire leakage current recovery circuit according to the present invention is a circuit for recovering leakage current flowing in electrical equipment connected to the secondary side of a transformer, and comprises: a first passive element disposed between the R line of the transformer secondary side and a leakage current enclosure grounding part of the electrical equipment; a second passive element disposed between the S line of the transformer secondary side and the leakage current enclosure grounding part of the electrical equipment; and a third passive element disposed between the T line of the transformer secondary side and the leakage current enclosure grounding part of the electrical equipment, wherein the leakage current enclosure grounding part is a part of the enclosure of the electrical equipment that is not insulated, where electric leakage occurs when current flows.

The invention relates to a three-core cable zero-sequence current direction checking device and method, and belongs to the technical field of power system relay protection, and the checking device comprises a coupling unit which is provided with a three-core cable connector and is used for injecting a transient excitation signal into a zero-sequence loop, acquiring an injection signal reference quantity corresponding to the transient excitation signal; the acquisition unit is provided with a mutual inductor connector, and the acquisition unit is used for acquiring transient response current caused by the transient excitation signal in a zero sequence loop; and the host is connected with the coupling unit and the acquisition unit, and the host judges the direction of the zero-sequence current according to the reference quantity of the injection signal and the transient response current. The coupling unit and the acquisition unit detect the transient response current on the zero-sequence loop through non-probing contact, the direction of the zero-sequence current is judged by comparing the injection signal reference quantity and the transient response current, and power failure is not needed in the whole process.

A device (100) for diagnosing an electric motor that is driven by an inverter (17), the device (100) comprising an electric current detection circuit (7) for detecting an electric current of the electric motor (5), and a computation processing unit (10) for receiving an output of the electric current detection circuit (7) and determining a winding short-circuit abnormality in the electric motor (5). The computation processing unit (10) has an operation state determination unit (41) for determining an operation state of the electric motor (5), an initial reverse-phase electric current analysis unit (31) for analyzing an initial reverse-phase electric current during a normal state, and an inverter-driving frequency calculation unit (22). The computation processing unit (10) is configured to determine a winding short-circuit in the electric motor in accordance with the inverter-driving frequency by using, as an evaluation value, the difference of the reverse-phase electric current calculated from the electric current of the electric motor during operation from the initial reverse-phase electric current, and therefore a short-circuit malfunction of stator windings of the electric motor can be detected with high accuracy.

The present application relates to the technical field of power generation motor, and discloses a power generation motor insulation state prediction method and system. The method collects three-phase stator current signals and operation mode identification signals of the power generation motor, and constructs an insulation degradation characteristic vector. The power generation mode and the motor mode are distinguished based on window average active power, and an operation mode variable and a mode change indicator are constructed. The basic coupling coefficient between the degradation characteristics is calculated, the coupling weight is adjusted by introducing a mode sensitivity function, an adaptive adjacency matrix driven by the operation mode is constructed, and the event-driven update of the graph structure is realized. Based on the adaptive graph structure, spatial feature extraction and time dimension fusion are carried out, and a normalized insulation health index is output for state evaluation and trend analysis. The method can weaken the influence of the difference between the two working conditions on the coupling relationship of the characteristics, improve the stability and reliability of the insulation degradation evaluation, and is suitable for online monitoring and early warning of the power generation motor of the pumped storage unit.

A balance characteristic test device for a zero-phase current transformer, which can perform a balance characteristic test using a small output current source. The device includes: an electric wire (1) disposed so as to penetrate a through-hole of a zero-phase current transformer (100) in a plurality of round trips; a current source (2) that causes a direct current to flow through the electric wire (1); and an ammeter (3) that measures the magnitude of a secondary current of the zero-phase current transformer (100).