Abstract: The present disclosure pertains to systems and methods for detecting faults in an electric power delivery system. In one embodiment, a system may include a data acquisition subsystem configured to receive a plurality of representations of electrical conditions. The system may also include a traveling wave differential subsystem configured to determine an operating quantity based on the plurality of representations of electrical conditions. The traveling wave differential subsystem may also determine a restraint quantity based on the plurality of representations of electrical conditions. The traveling wave differential subsystem may detect a traveling wave generated by the fault based on the plurality of representations. A fault detector subsystem may be configured to declare a fault based on a comparison of the operating quantity and the restraint quantity. A protective action subsystem may implement a protective action based on the declaration of the fault.

Abstract: Accurate measurements of electrical power at various points of a power grid is becoming more important and, at the same time, is getting more difficult as the old power distribution model of a few, large power generating stations and a multitude of relatively linear loads is replaced by a newer model containing a multitude of smaller, and to some degree unpredictable power sources, as well as a multitude of not always linear and often smart (essentially also unpredictable) loads. Embodiments of the invention provide for high accuracy voltage, current and power measurements of quasi-stationary and stationary waveforms in single and multiple phase power systems. Precision AC voltage, current, phase, power and energy measurements in power networks may be measured with current ranges from 1 mA to 20 kA and voltage ranges from 1V to 1000 kV and in a frequency range from a few hertz to one hundred kilohertz.

Abstract: The invention relates to Modular multilevel converter valve protection method, the modular multilevel converter valve consists of 6 arms, the arm includes sub modules, 1 arm is controlled by 1 control host, 6 control hosts is controlled by 1 summary control host, the method of the invention includes that the arm realizes locking sub module, bypass sub module, trip requests and system switching request and the summary control host implements summary and control response. The invention improves the reliability of two protection system through the use of dual redundancy protection method, clears the protection division through the layered protection frame of the upper summary control host and multi arm control host. And finally, it improves the whole safety and reliability of the modular multilevel converter valve.

Abstract: A connector which dispenses with an actuator and lowers profile while prevent damage to conducive path portions. A metal plate of the connector includes a first supporting portion mounted on a printed wiring board, and a second supporting portion connected to the first supporting portion via a linking portion in a manner movable in an FPC sandwiching direction. The second supporting portion includes a spring portion for urging a movable portion against FPC, a pair of locking pieces for increasing distance between contact point portions of the supporting portions by moving the movable portion away from the first supporting portion using an FPC inserting force, and suppressing removal of completely inserted FPC. Connection portions of conductive path portions are arranged on first and second protuberance portions at opposite ends of the first supporting portion in a connector left-right direction, along the connector front-back direction.

Abstract: A method for identifying root cause failure in a multi-parameter self learning machine application model is presented. At least one multi-function sensor having the capability to measure at least one of a voltage and current of the machine application model is provided. The method includes measuring voltages and currents of a multi-phase load with the multi-function sensors in a passive manor and calculating at least one of a time-varying variable KW, PF, kVAr, or Z out of the measured voltages and currents. The method further provides calculating a first, second or third order derivative of the time-varying variable and classifying segments of at least one of the time-varying variables depending on a state. Then, a step of choosing at least one of the variables and learning their normal behavior is undertaken. Finally, normal behavior is compared to a pattern difference and a root-cause meaning to the pattern difference is identified.

Abstract: A power consumption management system includes: a main part that is connected to a power line; a breaker that is electrically connected to the main part, and limits a current supplied to a load to a predetermined set value; a sensor unit including a current sensor and a signal processing part. The current sensor measures a current supplied from the main part to the breaker, and outputs a current detection signal based on the measured current. The signal processing part receives the current detection signal over a predetermined time, determines a range of a signal level from the received current detection signal, and adjusts an input range of the current detection signal in accordance with the determination result.

Abstract: A gate drive unit includes a measurement unit, a multi-resistive driving device, and a processing unit. The measurement unit measures a voltage across main terminals of a power switch. The driving device includes plural individually controllable resistive elements. The processing unit controls a control voltage applied to a control electrode of the power switch to activate the power switch. The processing unit individually activates or deactivates the resistive elements of the multi-resistive driving device to change which of the resistive elements at least partially conducts the control voltage to the power switch at different times responsive to the voltage across the main terminals representing a short circuit event. The processing unit changes which of the resistive elements are activated or deactivated to control a rate at which the control voltage decreases.

Abstract: A circuit performs a method for controlling turn-off of a semiconductor switching element. The method includes determining at least one operating parameter for the semiconductor switching element during an operating cycle and determining a gate discharge current based on the at least one operating parameter. The method further includes supplying the gate discharge current to a gate of the semiconductor switching element during a subsequent operating cycle to turn off the semiconductor switching element.

Abstract: A control circuit has an input terminal for receiving an input voltage, an energy accumulator for storing electric energy from the input terminal and supplying power to an electrical load, and an over-voltage protection unit for lowering the voltage at the input terminal when the voltage at an output terminal of the energy accumulator exceeds a predetermined threshold value. A motor device combines the control circuit with an electric motor as the load.

Abstract: A protection circuit includes a protection module and a fan electrically connected to the protection module. The protection module includes a control chip, an inverter, and an electronic switch. An input terminal of the inverter is electrically connected to a voltage output terminal and the fan, and further electrically connected to a clear pin of the control chip. An output terminal of the inverter is electrically connected to a preparation pin of the control chip. A first terminal of the electronic switch is electrically connected to an output pin of the control chip. The first and second terminals of the electronic switch are electrically connected to a power source terminal. A third terminal of the electronic switch is electrically connected to the voltage output terminal. When the fan short-circuits, the power source terminal stops supplying power to the fan through the voltage output terminal.

Abstract: Systems and methods for detecting fault conditions in a rotor of an electric induction motor are disclosed. In certain embodiments, a method for detecting fault conditions may include sampling a plurality of currents from an electric induction motor to obtain a plurality of current data points, calculating a global maximum magnitude of the plurality of current data points in the frequency domain over a range of predetermined frequencies, calculating an average magnitude of the plurality of current data points in the frequency domain over the range of predetermined frequencies, and declaring a motor rotor fault condition based on a comparison between the average magnitude and a first predetermined threshold, a comparison between a difference between the global maximum magnitude and the average magnitude and a second predetermined threshold, and a comparison between the global maximum magnitude and at least a third predetermined threshold.

Abstract: A method of protecting a synchronous machine (10) connected to an electricity network (12) against pole-slip comprises the steps of continuously monitoring a power transfer angle (?) between an electromotive force (EMF) of the machine and a reference voltage Vref. In the event of a fault (24) on the electricity network which may result in pole-slip of the machine (10), deriving a representation of power transfer (P) relating to the machine against the power transfer angle (?) utilizing data relating to a value of a current or a voltage measured on a terminal (26) of the machine before the fault has occurred and computed data relating to an expected future value of a current or voltage on the terminal (26), after the fault has occurred. The method then utilizes the representation and a stability criterion to predict whether the machine (10) may become unstable and if instability is predicted, causes the machine (10) to be disconnected at 32 or 34 from the electricity network (12).

Abstract: An electric switch is disclosed, in particular an electric circuit breaker. In at least one example embodiment, the switch includes a measuring channel for measuring an electric measured variable and is switched off when the result of a measurement reaches or exceeds a limit value. To test the mode of operation of the measuring channel, the electric measured variable is switched to a reference channel and a reference signal source is switched to the measuring channel and the reference result obtained via the measuring channel is compared with a reference setpoint. The switch is also tripped if, to test the mode of operation of the measuring channel, the electric measured variable is switched to the reference channel and the result obtained via the reference channel reaches or exceeds the limit value.

Abstract: An electronic fuse circuit for interrupting a current flowing through a power circuit includes: a trip switch structured to open and close to interrupt and permit, respectively, the current flowing through the power circuit; a current sensing circuit structured to sense when a magnitude of the current flowing through the power circuit is greater than a predetermined magnitude; a trip circuit structured to control the trip switch to open and close based on the sensed magnitude of the current flowing through the power circuit; and a processor having a routine structured to monitor a characteristic of the trip circuit and, when the monitored characteristic meets a predetermined criteria, to enter an override mode and control the trip circuit to control the trip switch to open regardless of the magnitude of the current flowing through the power circuit.

Abstract: In one general aspect, an apparatus can include an overvoltage protection portion, and an overcurrent protection portion operably coupled to the overvoltage protection portion such that heat produced by the overcurrent protection portion at a current below a rated current of the overcurrent protection portion causes the overvoltage protection portion to change from a voltage regulation state to a shorted state.

Abstract: Methods and systems for protecting DC circuits are provided. In an aspect, a method for controlling at least one protection circuit is disclosed. The method can monitor one or more parameters of the at least one protection circuit. One or more control signals can be selectively provided to a plurality of switches in the at least one protection circuit based on one or more parameters of the at least one protection circuit, in order to implement the appropriate protective topology based on one or more parameters of the at least one protection circuit. The method can be used to control a plurality of switches in the protection circuit and protect the DC circuit against short circuit, instabilities, and bus outages, and the like.

Abstract: A power module includes a current sensing circuit in which a transistor includes an emitter connected to a sense emitter of a current sense element of an IGBT and a base connected to ground, a current sensing resistor including one end thereof connected to a collector of the transistor and the other end thereof connected to a common connection portion. The power module detects, as a current sensing voltage, a potential difference generated by the current sensing resistor based on the common connection portion as a reference, compares the current sensing voltage with a predetermined threshold voltage, and determines whether or not an overcurrent flows through the IGBT according to a magnitude relation therebetween.

Abstract: A two-pole circuit breaker is provided that includes a first mechanical pole, a second mechanical pole and an electronic pole. The first mechanical pole includes a first armature having a first armature extension, and the second mechanical pole includes a second armature having a second armature extension. The electronic pole includes a first solenoid and a second solenoid, the first armature extension is disposed adjacent the first solenoid, and the second armature is disposed adjacent the second solenoid. Numerous other aspects are provided.

Abstract: A fault current limiter circuit including a fast switch fault current limiter (FSFCL) and a voltage control reactor (VCR) operative to conduct load current during a steady state operation and limit load current when the load current exceeds fault current limits. The FSFCL may include a breaker having electrical contacts, a coil electrically coupled to the electrical breaker contacts, a plunger mechanically coupled to the electrical breaker contacts, a parallel voltage control (VCR), a transient overvoltage control circuit (TOCC), wherein when current greater than a threshold level flows through the coil, a magnetic field having strength to move the plunger is generated, the movement of the plunger operates to open the contacts in the breaker and transfer fault current to VCR and TOCC and limit the overall system fault current.

Abstract: A system includes a refrigerant compressor including an electric motor, a current sensor that measures current flow to the electric motor, a switching device configured to close and open to allow and prevent current flow to the electric motor, respectively, a maximum continuous current (MCC) device that includes a resistance corresponding to a maximum continuous current for the electric motor, and a motor protection module. The motor protection module communicates with the MCC device, the current sensor, and the switching device and determines a first MCC value for the electric motor as a function of the resistance of the MCC device. The motor protection module also selectively sets a predetermined MCC to the first MCC and controls the switching device based on a comparison of the current flow to the electric motor and the predetermined MCC.

Abstract: An electronic fuse circuit for interrupting a current flowing through a power circuit includes: a trip switch structured to open and close to interrupt and permit, respectively, the current flowing through the power circuit; a current sensing circuit structured to sense when a magnitude of the current flowing through the power circuit is greater than a predetermined magnitude; a trip circuit structured to control the trip switch to open and close based on the sensed magnitude of the current flowing through the power circuit; and a processor having a routine structured to monitor a characteristic of the trip circuit and, when the monitored characteristic meets a predetermined criteria, to enter an override mode and control the trip circuit to control the trip switch to open regardless of the magnitude of the current flowing through the power circuit.

Abstract: An apparatus includes a power supply configured to supply power and a first electrical circuit breaker electrically coupled to the power supply. The apparatus includes a first electrical circuit electrically coupled to receive power from the power supply through the first electrical circuit breaker. The apparatus includes a second electrical circuit breaker electrically coupled to the power supply and a second electrical circuit. During operation of the apparatus, in response to detection that at least one of the current and the voltage of the power has exceeded the operating threshold for the first electrical circuit, the power supply and the first electrical circuit breaker are configured to power off, wherein the shutting off of the power supply prevents supplying the power from the power supply to the second electrical circuit breaker that is electrically coupled to the second electrical circuit to receive the power from the power supply.

Abstract: In one general aspect, an apparatus can include an overcurrent protection device. The apparatus can include an overvoltage protection device coupled to the overcurrent protection device and configured to cause the overcurrent protection device to decrease a current through the overvoltage protection device after a breakdown voltage of the overvoltage protection device increases in response to heat.

Abstract: A method, system, and/or apparatus is described for controllably providing operating power to, and indicating proper operating status of, a load. Novel functionality can be provided via discrete electronic components or components can be integrated into a unified enclosure as a starter apparatus. Operation can be based, at least in part, on an operating mode selected via a user interface. An electronic overload relay or overload circuit interconnected with a control board assembly and a contactor relay can sense one or more aspects of the operating power supplied to the load and the control board assembly can operate one or more relays to indicate operating status of the load and control the load in response to various manual or remote automation system inputs.

Abstract: A power supply device for plasma processing, wherein electric arcs may occur, comprises a power supply circuit for generating a voltage across output terminals, and a first switch connected between the power supply circuit and one of the output terminals. According to a first aspect the power supply device comprises a recovery energy circuit connected to the output terminals and to the power supply circuit. According to a second aspect the power supply device comprises an inductance circuit including an inductor and a second switch connected parallel to the inductor. According to a third aspect the power supply device comprises a controller for causing the power supply circuit and the first switch to be switched on and off. The controller is configured to determine a quenching time interval by means of a self-adaptive process. The quenching time interval defines the time interval during which, in an event of an arc, no voltage is generated across the output terminals.

Abstract: A programmable protection circuit of a battery pack and a battery back are disclosed. The protection circuit includes programmable protection level specifications based on battery characteristics by incorporating a storage unit therein. Accordingly, the protection circuit can be use with various batteries in various battery packs, thereby saving design and manufacturing costs.

Abstract: A high-side output transistor and a low-side output transistor of an output circuit control voltages of conductors, which connect a power supply terminal and ground, and outputs a voltage signal to an output terminal through an output conductor. A voltage output circuit detects a voltage applied to the high-side output transistor based on a potential difference of a first resistor provided closer to the output terminal side. A comparator circuit outputs a signal to turn off a first switch and a second switch provided in the conductors, when the output voltage of the voltage output circuit exceeds a reference voltage Vr.

Abstract: Disclosed is a controller for controlling short-circuit across positive and negative terminals of a dye sensitized solar cell for converting a light energy into an electrical energy. The controller includes: a voltage detecting section detecting a voltage developed across the positive and negative terminals of the cell; a current detecting section detecting a current caused to flow through the positive terminal of the cell; a judging section judging how a power generation state of the cell is, and whether or not a release state is provided across the positive and negative terminals of the cell in accordance with a value of the voltage detected by the voltage detecting section and a value of the current detected by the current detecting section; and a short-circuiting/releasing section short-circuiting or releasing across the positive and negative terminals of the cell in accordance with a result of the judgment made by the judging section.

Abstract: A power interruption circuit for use in a power distribution module is provided. The power interruption circuit is configured to provide power to a load and includes a shunt resistor, a plurality of switches, and microprocessor. The microprocessor is configured to determine a digitized value of a current flowing through the shunt resistor, determine a digitized value of an output voltage of the power interruption circuit, calculate, from the digitized current value and the digitized output voltage value, a power provided by the power interruption circuit to the load, compare the calculated power to a threshold power level, and control the plurality of switches based on the comparison.

Abstract: A power supply device for plasma processing, wherein electric arcs may occur, comprises a power supply circuit for generating a voltage across output terminals, and a first switch connected between the power supply circuit and one of the output terminals. According to a first aspect the power supply device comprises a recovery energy circuit connected to the output terminals and to the power supply circuit. According to a second aspect the power supply device comprises an inductance circuit including an inductor and a second switch connected parallel to the inductor. According to a third aspect the power supply device comprises a controller for causing the power supply circuit and the first switch to be switched on and off. The controller is configured to determine a quenching time interval by means of a self-adaptive process. The quenching time interval defines the time interval during which, in an event of an arc, no voltage is generated across the output terminals.

Abstract: A power supply device for plasma processing, wherein electric arcs may occur, comprises a power supply circuit for generating a voltage across output terminals, and a first switch connected between the power supply circuit and one of the output terminals. According to a first aspect the power supply device comprises a recovery energy circuit connected to the output terminals and to the power supply circuit. According to a second aspect the power supply device comprises an inductance circuit including an inductor and a second switch connected parallel to the inductor. According to a third aspect the power supply device comprises a controller for causing the power supply circuit and the first switch to be switched on and off. The controller is configured to determine a quenching time interval by means of a self-adaptive process. The quenching time interval defines the time interval during which, in an event of an arc, no voltage is generated across the output terminals.

Abstract: Processes, machines, and articles of manufacture that may serve to enable the detection or determination of alternating line voltages from an alternating power source, such as the power grid, are provided. This automatic sensing may be useful when connections are made to the power grid, such that when connections are made, the connections may be configured to be compatible with the available power source. This automatic sensing may also be useful if power sources change characteristics over time or if devices may be connected to different power sources over time.

Abstract: The disclosed technology describes methods and apparatus to convert and control power provided to a precipitator. An example embodiment of the disclosed technology includes a method for providing power to a device. The method includes receiving a first silicon controlled rectifier (SCR) signal and a second SCR signal from a controller device, generating a demand signal by the controller device based on a comparison of the first and second SCR signals, transmitting the demand signal to a power converter device, converting a first power signal from a first base frequency to a second power signal at a second base frequency, wherein the first base frequency is in the range of approximately 50 Hz to approximately 60 Hz and wherein the second base frequency is controlled in the range of approximately 100 Hz to approximately 1000 Hz, and switching the second power signal to the controller device.

Abstract: A protection circuit includes a first input, an over-voltage protector, an over-current protector, and a first output connected in series in that order. The first input is configured for receiving a power source. The first output is configured for outputting a voltage of the power source to a load circuit. The over-voltage protector is configured to cut off an electrical connection between the first input and the first output under the condition that a voltage value of the power source is greater than a predetermined voltage value. The over-current protector is configured to cut off an electrical connection between the first input and the first output under the condition that a current value from the first output is greater than a predetermined current value.

Abstract: Embodiments of the invention relate to automated three phase power monitoring systems. Embodiments of the invention include a zero crossing activated switch having an overload condition signal input that is electrically connected to a signal output terminal. The zero crossing activated switch prohibits conduction of the overload condition signal to a neutral ground RMS reactive breaker control mechanism until the zero crossing activated switch determines that at least one of three alternating currents crosses zero relative to a neutral signal.

Abstract: To provide a protection circuit for a load circuit which can distinguish between an overcurrent generated at a load and a rush current generated at the time of turning on a semiconductor switch or switches provided on the downstream side of the semiconductor switch and can turn the semiconductor switch off only when the overcurrent is generated to thereby protect the load circuit. A comparator CMP1 compares a detection current I1 detected by an ampere meter 15 with a threshold current Iref set in advance. When the detection current I1 reaches the threshold current Iref, the semiconductor switch 11 is turned off to thereby protect the load circuit. Further, a voltage Vd on an electric wire coupling between a battery VB and the semiconductor switch 11 is measured. When a counter electromotive force is generated and the voltage Vd reduces, the threshold current Iref is reduced according to the voltage reduction.

Abstract: This disclosure relates an arrangement for protecting an electricity network against disturbances caused by for instance switched power techniques. By providing a filter, disturbances as generated in an interior network are attenuated by the filter and fed to an electrical inlet.

Abstract: A protection system for high voltage direct current, HVDC, transmission lines is provided. The protection system includes a direct current, DC, bus, a device configured to connect an HVDC transmission line to the bus, at least one DC circuit breaker arranged for disconnecting the transmission line from the bus upon reception of a trip signal, current and voltage sensors, an inductor arranged such that the current through the transmission line passes the inductor, and a fault detection unit. The fault detection unit is arranged for assessing, on the basis of current and/or voltage measurements, whether a fault exists on the transmission line, and sending, if a fault is detected on the transmission line, a trip signal to the circuit breaker. The additional inductance limits the rise in fault current and facilitates a selective fault detection. Further, a method of fault protection for an HVDC transmission line is provided.

Abstract: A method to avoid a single point of failure in a system that includes at least two monitoring devices, at least two power supplies and a switching device coupled between the monitoring devices and the power supplies. The method includes performing a test that can determine if two monitoring devices are receiving power from the power supply, generating an error code and varying a position of one or more switches in a switching device based on the error code.

Abstract: A high sensitivity leakage current detection interrupter (LCDI) includes a shielded wire, a current leakage detection unit, and a tripping mechanism. A live core and a neutral core of the shielded wire are respectively wrapped in two conductive shell wires. The current leakage detection unit includes a pair of rectifying diodes reversely connected in series between a live line and a neutral line of a power supply, a voltage dropping resistor, thyristors, and resistor-capacitor (RC) voltage dropping filter circuits. The tripping mechanism includes control units with on/off respectively controlled by the thyristors. When either of the thyristors is turned on, the corresponding control unit is turned on, and the tripping mechanism is actuated to switch off the power supply.

Abstract: A method for protecting a bipolar power distribution network supplied with power by an electric power source isolated from an electrical ground of an aircraft. The network includes a resistive protection device configured to be connected to the electrical ground and to the two phases of the network. The method includes the steps of receiving at least one voltage value on at least one of the two phases and/or at least one current value in the electrical ground, comparing the at least one voltage value with a first predetermined threshold value and/or the at least one current value with a second predetermined threshold value and controlling the protection device by changing its resistivity according to the comparison.

Abstract: The present invention provides a transistor circuit with protecting function. The transistor circuit includes a transistor, a voltage detecting unit, a current detecting unit, a temperature detecting unit, and a protecting unit. The voltage detecting unit detects a voltage drop of the transistor and generates an over-voltage protection signal. The current detecting signal detects a current flowing through the transistor and generates an over-current protection signal. The temperature detecting unit detects a temperature of the transistor circuit and generates an over-temperature protection signal. The protecting unit is coupled to the control terminal to control a state of the transistor according to the over-voltage protection signal, the over-current protection signal, and the over-temperature protection signal to reduce the voltage difference between the control terminal and the second terminal, such that the voltage drop of the transistor is decreased or decreased to zero.

Abstract: Disclosed are systems and methods for monitoring an electrical wire. A safety device utilized to monitor the wire may include at least one current sensing device, at least one voltage sensing device, and at least one processing component. The current sensing device measures a current on at least one conductor of the wire. The voltage sensing device measures a voltage associated with the safety device. The at least one processing component receives the measurements and identifies, based upon the current measurement, an overcurrent event. The processing component then compares the voltage measurement to a stored voltage value and determines, based upon the comparison, that a difference between the voltage measurement and the stored voltage value satisfies a threshold condition. The processing component directs, based upon the determination, at least one relay to be opened to discontinue provision of an electrical power signal onto the electrical wire.

Abstract: A method for power quality protection includes measurement of electrical and nonelectrical parameters, calculation of additional electrical and nonelectrical parameters, comparison of the value of the calculated parameters with maximum allowed values from a power quality perspective, activation of protection mechanisms for transitioning to a safe mode or for isolation from the bus. The systems and methods may prevent equipment failures when out of the spec power quality is present in the distribution bus and may protect the distribution bus from imposing power quality problems due to equipment failures. Because most of the sensors in the systems of the present invention are already used for other control and protection purposes, there may be no reliability degradation. Most of the calculations and the control logic may be performed digitally for improved reliability and flexibility to modify algorithms.

Abstract: For a system to avoid abnormal operation caused by a shorted parameter setting pin of an integrated circuit, a protection apparatus and method apply a buffered reference voltage to the parameter setting pin to define an internal parameter of the integrated circuit by the buffered reference voltage and an external element connected to the parameter setting pin, and detect the rapid variation of the internal parameter to trigger a shutdown signal or slow down the speed of the variation of the internal parameter reflected to an adjustable signal of the integrated circuit.

Abstract: A semiconductor device includes a load current path operable to carry a load current from a supply terminal having a supply voltage to an output circuit node. The device further includes a voltage comparator configured to compare the supply voltage with a voltage threshold and to signal a low supply voltage when the supply voltage reaches or falls below the voltage threshold. An over-current detector is configured to compare a load current signal that represents the load current with an over-current threshold and to signal an over-current when the load current signal reaches or exceeds the over-current threshold. Furthermore, the semiconductor device includes a control logic unit that is configured to deactivate the load current flow when an over-current is signalled and to reduce the over-current threshold from a first value to a lower second value as long as the voltage comparator signals a low supply voltage.

Abstract: The present invention relates to methods for providing impedance protection differentiating between in-zone and out-of-zone faults based on instantaneous, digitally derived operating and polarizing distance comparator signals. The method uses a pair of fast orthogonal filters to derive D and Q components of the input voltages and currents. Two sets of operating and polarizing signals are derived for better speed of response under varying fault moment with respect to the peaks and zero crossings of power signals. Three stages of comparison between the operating and polarizing impedance terms are used. These comparator stages use half a cycle averaging windows, and three-quarters-of-a-cycle windows. The first stage of comparison is based on energy comparator responding to both magnitude and phase information in the signals. Stages 2 and 3 are of phase comparison type, responding mostly at the phase information and neglecting the magnitude information for better immunity to noise and signal distortions.

Abstract: A bidirectional switch device, has: a bidirectional switch having a HEMT; and a control circuit which, during a first condition, applies a first voltage lower than a threshold voltage across a gate and one terminal among a source and a drain of the HEMT to turn off a first current path from the other terminal among the source and the drain to the one terminal, and during a second condition, applies a second voltage lower than the threshold voltage across the other terminal and the gate to turn off a second current path from the one terminal to the other terminal, and further during a third condition, applies a third voltage higher than the threshold voltage across the source and the gate and across the drain and the gate of the HEMT to turn on the first and second current paths.

Abstract: A differential protection system including a plurality of inputs power cables for transfer of power from electric power generators, such as wind power generators, to an output cable. Each input and output power cable is provided with a respective circuit breaker. The protection system includes a plurality of protection equipment unit each being adapted to be arranged at a respective one of the input cables or at the output cable, each protection equipment unit including a measuring unit for measuring the current and voltage of the cable, and including a control unit being operatively connectable to the circuit breaker of the respective power cable for selectively tripping the circuit breaker when the protection system discovers a differential fault. The protection system includes a charging current compensator for compensating the differential protection for charging currents of the cables of the transfer system.

Abstract: A power circuit protection system includes a current sensor configured to measure a first current level through a conductor of the circuit, a voltage sensor configured to measure a first voltage level across a plurality of conductors of the circuit, and a controller communicatively coupled to the current sensor and to the voltage sensor. The controller is configured to receive a first signal from the current sensor, wherein the first signal is representative of the first current level, and receive a second signal from the voltage sensor, wherein the second signal is representative of the first voltage level. Based on the first signal and the second signal, the controller is configured to determine whether to activate a first circuit protection device or a second circuit protection device.