4171 results about "Short circuit fault" patented technology

Relative comparison is made between a voltage applied to the whole of the first through eighth LEDs and a voltage applied to the first LED by a comparator. When the voltage applied to the whole of the LEDs has relatively dropped with respect to the voltage applied to part of the LEDs, the comparator outputs a Low Level signal, assumes an abnormality that accompanies a short-circuit fault in any one of the LEDs and causes a ninth LED to illuminate. Meanwhile, relative comparison is made between a voltage applied to the whole of the first through eighth LEDs and a voltage applied to the first LED by another comparator. When the voltage applied to the whole of the LEDs has relatively dropped with respect to the voltage applied to part of the LEDs, the comparator outputs a Low Level signal, assumes an abnormality that accompanies a short-circuit fault in the first LED and causes a ninth LED to illuminate.

Short circuit failures and open circuit failures of light-emitting elements used for the backlight in an LCD panel can be reliably and easily detected. The voltage at the node between each series-connected light-emitting element array and a drive circuit is detected as a monitored voltage. A maximum detector detects the highest and a minimum detector detects the lowest of these monitored voltages. Short circuit or open circuit failure of a light-emitting element is detected by comparing the voltage difference between the maximum detector output and the minimum detector output with a specific reference voltage.

This invention relates to one gas wheel motor rotor coil shortcut online test method in the test technique field, which comprises the following steps: through online real time collecting motor electrical parameter data and according to one certain work situation motor electrical parameter data to compute normal current theory values by reverse rotor normal current; then computing excitation magnetic current real value and theory value relative bias; the bias difference is as generation motor set to judge whether there is coil short cut fault as dialogue of the shortcut fault.

When a short-circuit failure of any of switch portions (13) including switch elements (11) and parallel-connected feedback diodes (12) of an inverter circuit (7) is detected during the operation of a motor (1), a switch portion (13) where the short-circuit failure has occurred is checked for whether it is on the positive polarity side or the negative polarity side. The switch elements (11) are so controlled that all the switch portions (13) on the same polarity side as where the short-circuit has occurred are brought into a conducted state and all the others disconnected. This prevents a large electric current from flowing into each switch portion of the inverter circuit without requiring any switch to block the power distribution between a motor and the inverter circuit when a short-circuit failure of the switch portion of the inverter circuit occurs.

The invention relates to a online testing process for shorted fault of asynchronous motor's stator winding, which is belong to Detecting Technology. It was designed to solve the detecting problem of stator winding. The project is that it figures out the voltage and current of negative sequence and positive sequence of the stator winding by collecting three-phase stator voltage, instantaneous-current signal. Then using of normal motor sample reference document estimated the filter value of the stator negative sequence, figured out the stator negative sequence current fault component. And then base on the threshold of the stator negative sequence current fault component educe failure exponent. Finally according to the index judge whether to exist short circuit failure or not. This invention also gave corresponding detection device. Not only can high sensitivity, high reliability and on-line measurement asynchronous motor stator windings at the beginning of the early short circuit fault, but also can judge short circuit phase. This can effectively ensure the asynchronous motor operating safely.

A voltage application unit applies voltage to windings of a motor without passing though an inverter unit. A first detection unit detects a short circuit failure in switching elements of the inverter unit based on a terminal voltage between each of the switching elements and a corresponding winding and a power voltage of a power supply. Before rotation of the motor, when no short circuit failure is detected and when a switching unit switches at least one of the high and low potential-side switching elements of the inverter unit on and subsequently switches all the switching elements off, a second failure detection unit determines whether the switching unit is incapable of rendering the switching element non-conductive based on the terminal voltage and the power voltage.

A bidirectional switching device has a first main semiconductor element and a second main semiconductor element. The first main semiconductor element has a first main electrode connected to an ungrounded side of an AC power source, and a second main electrode. The first main semiconductor element contains a first parasitic diode whose cathode region is connected to the first main electrode and whose anode region is connected to the second main electrode. The second main semiconductor element has a third main electrode connected to the second main electrode, and a fourth main electrode connected to a load. The second main semiconductor element contains a second parasitic diode whose anode region is connected to the third main electrode and whose cathode region is connected to the fourth main electrode. A current flowing from the first main semiconductor element toward the second main semiconductor element passes through the second parasitic diode, and a current flowing from the second main semiconductor element toward the first main semiconductor element passes through the first parasitic diode. The bidirectional switching device is used to form a semiconductor active fuse for an AC power system. The semiconductor active fuse is capable of detecting an overcurrent without a shunt resistor, which was connected in series to a power supply cable, thereby minimizing heat dissipation as well as a conduction loss. The semiconductor active fuse is capable of easily and speedily detecting not only an overcurrent caused by a dead short but also an abnormal current caused by an incomplete short circuit failure having a certain extent of short-circuit resistance, and breaking alternating current in an AC power supply cable.

The invention discloses an intelligent fault diagnosis method suitable for a microgrid. The method comprises the following steps: monitoring the operation state of the microgrid through acquiring voltage current signals on a bus of the microgrid, determining whether an internal fault occurs in the microgrid, and accordingly, determining the starting mode of the diagnosis of the microgrid fault; according to the set condition of a fault diagnosis mode, acquiring the voltage current signals on the bus of the microgrid and carrying out preprocessing; by use of a multi-wavelet package decomposition technology, extracting fault signal transient components of different frequencies; calculating wavelet singular entropy as a characteristic vector of an RBF nerve network fault diagnosis mode of the microgrid; and inputting the characteristic vector into the diagnosis mode, outputting fault state information of the microgrid. According to the invention, a microgrid external fault diagnosis function and an internal short circuit fault diagnosis function are simultaneously provided, and a basis is provided for operation control and correlation protection of the microgrid.

Each of three-phase arm of an inverter has first and second switching elements connected in series together at a connection point to the corresponding phase coil of the three-phase motor. Control device turns on the first switching element of the i-th (i is a natural number smaller than four) for a predetermined time period, and determines that the second switching element of the i-th arm has a short fault, when an overcurrent exceeding a predetermined threshold is detected within the predetermined time period. The predetermined time period is shorter than a time period from a time point of turning on the first switching element of the i-th arm to a time point of attaining the predetermined threshold by a current flowing through a path extending from a power supply line through the second switching element of the remaining arm other than the i-th arm to a ground line.

There are provided a semiconductor device in which short circuit failures in magnetic resistor elements and the like are reduced, and a method of manufacturing the same. An interlayer insulating film in which memory cells are formed is formed such that the upper surface of the portion of the interlayer insulating film located in a memory cell region where the magnetic resistor elements are formed is at a position lower than that of the upper surface of the portion of the interlayer insulating film located in a peripheral region. Another interlayer insulating film is formed so as to cover the magnetic resistor elements. In the another interlayer insulating film, formed are bit lines electrically coupled to the magnetic resistor elements. Immediately below the magnetic resistor elements, formed are digit lines.

The invention discloses a method for evaluating voltage dip sensitivity of sensitive equipment, belonging to the field of electric measurement. A voltage dip frequency of a power grid in a time section and depth and duration time of each voltage dip are monitored at a measurement point so as to establish a small sample set of practical voltage dips of the power grid in the time section, and a final evaluation result depends on equipment fault rate caused by measuring the voltage dip each time, so that influence degree of running conditions of the power grid in the time section on the sensitive equipment is really reflected, and influence of the voltage dips caused by various short-circuit faults in the power grids with different structures on the sensitive equipment can be reflected, so that related departments is guided to take more reasonable control measures or providing a basis for calculating economic loss caused by the voltage dips. Therefore, the method can be widely applied to the field of power supply quality control and management of the power grid.

A controller identifies a condition of a hazardous internal short by comparing patterns of series element voltages to the last known balance condition of the series elements. If the loaded or resting voltage of one or more contiguous series elements uniformly drop from the previously known condition by an amount consistent with an over-current condition, an over-current internal short circuit fault is registered. The desired response is to prevent the affected series elements from heating to a hazardous temperature by summoning the maximum heat rejection capability of the system until the short ceases and the affected elements cool, the cooling function is no longer able to operate due to low voltage, or the affected series string has drained all of its energy through the short. Also includes are responses that allow the battery pack to continue to power the cooling system even though it may enter an over-discharged state.

The invention relates to a device for rapidly detecting the short-circuit fault of a power system, which comprises a power supply circuit, an A / D sampling circuit, a voltage / current detection circuit, a digital signal processing signal and a protective signal output circuit, wherein the power supply circuit converts 220V alternating current into direct current for ensuring normal running of the entire device; voltages and currents in a power grid are transformed by an external transformer and then fed into the voltage / current detection circuit, voltage / current signals are formed by means of the regulation and setting of the voltage / current detection circuit, then converted by the A / D sampling circuit from analog quantity to digital quantity and at last output to the digital signal processing signal, the digital signal processing signal judges whether the short-circuit fault occurs, and if so, the digital signal processing signal controls the protective signal output circuit to send a protective signal. The device can judge the short-circuit fault according to the voltage / current signals at ports of each breaker only, and the detection time of the device is in general less than 5ms; and the device can facilitate expanding and updating power grid and reforming network.

The invention relates to a lightning striking fault identifying method of a direct current power transmitting line traveling wave protection. According to the characteristic difference of voltage traveling wave shape between the formed faults and unformed faults, two-pole voltage traveling wave weight and origin direct current weight are used to identify changing trend of the wave shape; ratio of a initial traveling wave mode maximum value and the second mode maximum value is used for representing saltation that the wave shape is cut; combining the two characteristics to achieve the identification of the voltage traveling wave while not causing the faults by lightning pole tower, lightning striking lightning line, lightning striking line shift central distance and the voltage traveling wave of non-lightning short circuit fault by the lightning pole tower, lightning striking line shift central distance. The interference and identification of the two lightning weaves are combined to improve the identifying reliability. A large number of emulations represent that this method is reliable and effective. The physical conception of this invention is intuitionistic and clear and has a rapid action function. The invention does not be influenced by the fault type and transition resistance and it is easy to achieve and suitable for apllying to direct current system protecting device.

The invention discloses a tri-level four-leg T-shaped fault-tolerant converter and a control method thereof. The fault-tolerant converter comprises a DC input circuit, a tri-level T-shaped topology device, a failure isolation circuit, a redundant leg, a fault-tolerant bridge and an AC output circuit, wherein a power switch tube corresponding to the redundant bridge is controlled to be switched on in the normal operating state when the neutral-point voltage of a DC bus fluctuates sharply, the neutral-point voltage is quickly adjusted to be balanced by introducing inductive current, over-voltage breakdown of the power switch tube caused by sharp fluctuation of the neutral-point voltage is prevented, and a bidirectional controllable thyristor corresponding to the fault-tolerant bridge is controlled to be switched on to enable the redundant bridge to replace a broken bridge for fault-tolerant operation when a failure occurs. According to the fault-tolerant converter, fault tolerance of open circuit and short circuit failures of the switch tube and legs can be achieved, and output power and DC voltage utilization rate can not be reduced. The tri-level four-leg T-shaped fault-tolerant converter can be applied to an AC motor driving system or a grid-connected power generation system, so that the system has a better fault-tolerant operation function.

The invention provides an identification method for transformer inrush current which belongs to power system main equipment relay protection technology field. The method has characteristics in that the method identifies inrush current and fault current base on waveform correlation degree. By comparison with each sampling point algebraic sum in dynamic differential current short data window, non-saturation region of transformer under inrush current and fault current is searched, two form standard sine waves are constituted of max value and position of sampling data in non-saturation region, then differential current sampling waveform in non-saturation region and two form standard sine waves correlation degrees are calculated respectively, inrush current and fault current are differentiated according with correlation coefficient average. The method can open longitudinal differential protection rapidly when internal fault and no-load closing with fault occur in transformer operation; and can lock longitudinal differential protection reliably when on-load closing occurs inrush current.

A shift position of an electric powered vehicle is selected by operating a shift lever and a P position switch. A power source position is selected by operating a power switch. When any of switching elements forming an inverter device is short-circuited, selection of the shift position and the power source position is controlled such that simultaneous selection of a power source position at which inverter control is turned off and a shift position at which a parking lock mechanism is inactivated can be avoided. Therefore, inverter control for reducing short-circuit current caused by back electromotive force derived from rotation of a motor generator after occurrence of short-circuit failure can reliably be executed.

The invention provides a switch reluctance motor double master switch power converter master switch fault diagnosis method. A current sensor LEM1 is arranged on the master switch current circuit (DC)busand and is used for testing the total current of the main switch on the DC bus, a current sensor LEM2 is arranged on the free-wheeling diode DC bus and is used for testing the total current feedback by the free-wheeling diode on the DC bus, the wires of the two current sensors are connected with a receiver to obtain the total current signal of the master switch and the total current signal fedback by the free-wheeling diode. The invention can be used for judging that short trouble occurs to both the upper master switch tube and the lower master switch tube and open fault occurs to both theupper main switch tube and the lower main switch tube, and can be used for carrying out fault location, thus having convenient fault-tolerant control, and wide application prospects.

A controller identifies a condition of a hazardous internal short by comparing patterns of series element voltages to the last known balance condition of the series elements. If the loaded or resting voltage of one or more contiguous series elements uniformly drop from the previously known condition by an amount consistent with an over-current condition, an over-current internal short circuit fault is registered. The desired response is to prevent the affected series elements from heating to a hazardous temperature by summoning the maximum heat rejection capability of the system until the short ceases and the affected elements cool, the cooling function is no longer able to operate due to low voltage, or the affected series string has drained all of its energy through the short. Also includes are responses that allow the battery pack to continue to power the cooling system even though it may enter an over-discharged state.

A fault protection system and method of fault protection for permanent magnet machine (PMM)-based systems that utilize machine neutral decoupling (MND) to shut down a shorted winding and / or to isolate a short-circuit fault to prevent damage to a permanent magnet machine and to any downstream components are provided. The invention may be used for high-reactance and / or high current PMM-based systems, such as are commonly found in industrial and aviation applications.

The invention discloses an on-line positioning method of a section with low-current ground faults and a system based on the positioning method. The method and the system are suitable for a neutral ungrounded power grid of 3-60kV. Under the operation condition of a line with single-phase ground faults, the phasor information of a zero-sequence voltage and the amplitude and phasor information of a zero-sequence current of the line are measured, and the section position of a fault point is determined according to the amplitude and phase information. The accuracy and rapidity of positioning are fully ensured, and the on-line positioning problem of single-phase ground faults of the neutral ineffectively grounded power grid and the monitoring problem of short-circuit faults between lines are effectively solved.

The invention relates to a fault diagnosis method for a power converter of a switch reluctance motor; current spectrum of the power converter phase of the switch reluctance motor is tested and used asfault characteristic quantity; and the proportion coefficient Lambada of relative spectrums ratio of the phase current is defined as the ratio of the amplitude of fundamental component of the phase current and the amplitude of direct current component of the phase current. If the coefficient of the relative spectrum ratio of all phase current is basically constant, the power converter does not occur fault; if the amplitudes of the direct current component and the fundamental component of a certain phase current are near to zero respectively, the phase occurs open fault; and compared with thecoefficient of the relative spectrum ratio of the phase current without fault, if the coefficient of the relative spectrum ratio of a certain phase current occurs obvious change, the phase occurs short fault. The method not only can be used for fault detection, discrimination for types of faults and positioning of fault phases when one phase of the power converter of the switch reluctance motor occurs fault, but also can be used for fault detection, discrimination for types of faults and positioning of fault phases when two or more than two phases of the power converter of the switch reluctance motor occur fault.

A controller identifies a condition of a hazardous internal short by comparing patterns of series element voltages to the last known balance condition of the series elements. If the loaded or resting voltage of one or more contiguous series elements uniformly drop from the previously known condition by an amount consistent with an over-current condition, an over-current internal short circuit fault is registered. The desired response is to prevent the affected series elements from heating to a hazardous temperature by summoning the maximum heat rejection capability of the system until the short ceases and the affected elements cool, the cooling function is no longer able to operate due to low voltage, or the affected series string has drained all of its energy through the short. Also includes are responses that allow the battery pack to continue to power the cooling system even though it may enter an over-discharged state.

The invention discloses a fault-tolerance circuit for an organic electroluminescence display / illumination device, comprising an addressing unit, a pressure-controlled current resource unit, a branch control unit, a zero setting unit, a main illumination device and a standby illumination device, wherein, the addressing unit is used for charging a capacitor member in the pressure-controlled current resource unit and setting a gate source voltage of a current resource transistor in the pressure-controlled current resource unit; the pressure-controlled current resource unit is used for providing power to the branch control unit; the branch control unit is used for receiving a constant current signal from the pressure-controlled current resource unit and judging the work states of a first switch transistor and a second switch transistor of the branch control unit; the zero setting unit is used for judging whether the first switch transistor in the branch control unit is grounded and making the first switch transistor work normally. According to the invention, the problem of asymmetry lightness resulted from a short circuit fault of pixel points during the using process of the display device or the illumination device is solved, and the lightness and power consumption of the device is maintained.

The invention relates to a processing method for distribution network short circuit fault, in particular to a method for detecting the distribution network short circuit fault and restoring power supply in a non-broken-down section, and capable of achieving feeder line automatic local control. Short circuit fault detectors A (29) to M (41) are utilized for detecting the short circuit fault, and then reclosing time selection devices A (16), B (17), C (18) and D (19) are utilized for restoring power supply in the non-broken-down section. When short circuit happens, outlet switch A (1) or B (2) and C (2) protect the tripping in a relay way, and during permanent short circuit, the outlet switch A (1) or B (2) and C (3) protect the tripping of a second time in the relay way, a short circuit fault switch is pressed to achieve zero current tripping closedown, and a non-fault switch detects residual voltage cut-off and closedown for the second time. The outlet switch A (1) or B (2) and C (3) are coincided for the second time, so that the fault section is separated, the operation time limit of the non-fault switch is longer than the second reclosing time, three-phase normal voltage can be obtained, and the tripping no longer happens. As for the condition that the power is supplied by round network, one side of an interconnection switch (23) is deprived of electricity, non-fault switch for switching-on and tripping is delayed, and the voltage switching-on is detected in sequence.

The invention discloses a direct current traction power supply system and a protective method, and utilizes direct current protective device outlet information and a short circuit fault mark value as a criterion to judge various direct current short circuit faults. When the short fault occurs, an alternating current incoming line breaker closest to a fault element is subjected to brake separating; if the sum of the fault mark values of the element, measured and computed after the brake separating, is more than or equal to 1, permanent fault is determined, the alternating current incoming line breakers of other traction substations in the whole line are subjected to brake separating, and related direct current isolation switches are subjected to brake separating to enable the alternating current incoming line breakers of the traction substation in the whole line to be subjected to switching on, so the power supply of the system can be restored; and if the sum of the fault mark values of the element is smaller than 1, the fault is instant, and related breakers are switched on for restoring the power supply of the system. The direct current traction power supply system and the protective method are capable of omitting the direct current breakers and saving investment, convenient to implement, suitable for carrying out new line construction or old line transformation in occasions where the lines are not very long (for example in 20m and less than 10 traction substations). When the line is overlong, the traction power supply system can be subjected to partition by a small amount of direct current breakers.

An active antenna power interface circuit couples a supply voltage from a radio receiver to an antenna feed. The circuit comprises a DC power input and a power switching element connected in series between the DC power input and the antenna feed. The power switching element has a control input for selecting a conducting state or a nonconducting state of the power switching element. A high side voltage sensor senses a first voltage proportional to a voltage at the DC power input. A low side voltage sensor senses a second voltage proportional to a voltage at the antenna feed. A controller is coupled to the control input and to the voltage sensors. The controller places the power switching element into the conducting state, samples the first and second voltages, calculates a voltage difference in response to the first and second voltages, compares the voltage difference to an upper limit and a lower limit. If the voltage difference is greater than the upper limit then the controller signals a short-circuit fault. If the voltage difference is less than the lower limit then the controller signals an open-circuit fault.

The invention relates to a power distribution network fault classification method based on the adaptive neuro-fuzzy inference system. The method is an improved method based on the adaptive neuro-fuzzy inference system. According to several frequently-occurring short circuit fault types of the power distribution network, a hierarchical based adaptive neuro-fuzzy inference system is constructed in the method, various short circuit faults are simulated based on a simulation software and the fault phase current is collected as the training sample data, and the blended learning algorithm is used for training the constructed hierarchical adaptive neuro-fuzzy inference system to determine the parameter in the system; the hierarchical adaptive neuro-fuzzy inference system with the determined parameter can be used for discriminating the fault types of the power distribution network. A lot of simulation data validations indicate that the classification method provided by the invention has a higher classification and identification accuracy, and has a better robustness on the variation of the fault points and a strong adaptability on the variation of the network topology.

The invention relates to a battery management system which comprises a vehicle-mounted battery management unit and a cloud calculation system based on battery historical data. The vehicle-mounted battery management unit conducts battery model parameter identification through voltage, current and temperature which are measured by a battery information acquisition unit, conducts state SOC and SOE estimation through identified parameters and achieves functions of multi-objective optimization charging and discharging capacity SOP estimation, battery short-circuit fault detection, sensor fault detection, sensor online calibration and battery self-heating and heat equilibrium and the like on the basis of model parameters. The characteristics that a cloud server is large in memory space and highin computing power are used for achieving online battery capacity estimation, namely the section of health SOH estimation, and battery pack consistency estimation and remaining mileage prediction areconducted through the model parameters and SOC information. The inner short-circuit condition of parameter slow time varying is estimated. The remaining useful life (RUL) is predicted through the historical charging data. Calculation results are transmitted back to the vehicle-mounted battery management unit through wireless transmission.

An electric plant with a safety device, a method for remedying faults in a switchgear installation, and the use of a closing contact to provide security against faults. The plant includes a switchgear installation, consumer loads connected to the switchgear installation, and at least one feeder cable to the switchgear installation. The plant provides a strong consumer network that still has a high degree of safety against damage caused by short-circuiting faults. The plant includes at least two feeder cables, each connected to its own current source such as a transformer or a generator. At least one of the feeder cables is connected by a branch cable to ground. The branch cable is provided with a closing contact, which is normally open. The closing contact is arranged to be activated, i.e. to quickly close the connection to ground, in the event of short-circuiting in the switchgear installation.