Abstract: Systems and methods are presented for detecting high-impedance faults (HIFs) in an electric power delivery system using a plurality of coordinated high-impedance fault detection systems. In certain embodiments, a method for HIFs may include receiving first and second current representations associated with first and second locations of the electric power delivery system respectively. Based on at least one of the first and second current representations, the occurrence of an HIF may be determined. A relative location of the HIF may be determined based on a relative amount of interharmonic content associated with an HIF included in the first and second current representations, and a protective action may be taken based on the determined relative location.

Abstract: A method for automatic protection coordination in a power system network comprises identifying radial source-to-load paths and fault protection devices in the source-to-load paths, for a portion of the power system network to be coordinated. Device settings data for fault protection devices are retrieved, including multiple preconfigured settings for some devices. Fault currents for each of multiple possible electrical faults in said portion of the power system network are predicted, and a selectivity check for each pair of fault protection devices that are adjacent to one another in an identified radial source-to-load path is performed, for each of one or more of the predicted fault currents, taking into account multiple preconfigured settings for remotely controllable fault protection devices.

Abstract: The invention relates to a method for providing short-circuit protection for a resistive AC load, wherein the load is connected with an AC power supply through an active controlled switch controlled by a controller. The method for providing short-circuit protection for the resistive AC load comprises the following steps of: turning on the active controlled switch within a first conduction angle range; obtaining the mean current value of the load through a current detection circuit; and determining whether the mean current value of the load is greater than a default value or not, wherein, if so, the active controlled switch is controlled to be turned off, and if not, the active controlled switch is controlled to be turned on. The invention also relates to a device and a switch for providing short-circuit protection for the resistive AC load.

Abstract: An overcurrent protection circuit for a high side solenoid switch includes a primary bias circuit and a secondary bias circuit. The secondary bias circuit is operable to alter a source to gate bias voltage of the high side solenoid switch during an overcurrent.

Abstract: A power distribution system includes a first circuit protection device and a second circuit protection device coupled to the first circuit protection device downstream of the first circuit protection device. The second circuit protection device includes a trip mechanism configured to interrupt a current flowing through the second circuit protection device, and a trip unit operatively coupled to the trip mechanism. The trip mechanism is configured to determine, for the second circuit protection device, a protective threshold and a blocking threshold that is lower than the protective threshold, transmit a forward blocking signal to the first circuit protection device upon a determination that the current exceeds the blocking threshold, and generate a reverse blocking signal upon a determination that the current exceeds the protective threshold.

Abstract: A battery protection apparatus is disclosed. In one aspect, the apparatus includes a temperature-dependent resistor electrically connected to at least one battery cell, wherein the temperature-dependent resistor is configured to change internal resistance in a substantially inversely proportional relationship to temperature of one or more of the at least one battery cell. The apparatus further includes a battery protection unit connected between the temperature-dependent resistor and the at least one battery cell, wherein the battery protection unit is configured to block the current flowing through one or more of the at least one battery cell when the current exceeds a first reference value.

Abstract: A device, such as an intelligent electronic device (IED), provides a monitoring and protective function for a power system. The protective function uses stimulus acquired from the power system to detect power system conditions and to take one or more protective actions responsive thereto. The device may detect arc flash events in the power system based upon electro-optical and/or current stimulus measurements obtained therefrom. The stimulus measurements may be recorded to use in metering, validation, identifying detector misoperation, and/or event oscillography.

Abstract: Provided is a short-circuit isolator capable of earlier detection of recovery from short circuit of a disconnected line and reconnecting the line.

Abstract: A circuit protection device and a protection method thereof are provided. The circuit protection device includes a pulse width modulation unit which detects in order for a plurality of current phase of a plurality of transistors. The pulse width modulation unit decides the current phase of the transistors override a first threshold value whether. Then, the pulse width modulation unit sends a control signal to close the transistor that the current phase exceeds the first threshold value, so as to avoid the transistor burn down.

Abstract: A semiconductor switching element drive circuit includes a semiconductor that passes main current between first and second terminals when voltage is imposed to a gate terminal, and an over current protection circuit that decreases the main current when the main current is judged to become over current for a certain period when exceeding a predetermined current value when current value or voltage value proportional to an amplitude of the main current exceeds a threshold value. The circuit also includes a short circuit protection circuit that decreases gate voltage imposed to the gate terminal earlier than a fall of the main current produced by the over current protection circuit when the main current becomes larger than the over current in a period shorter than the certain period, and a threshold value change circuit that decreases a threshold value when the short circuit protection circuit decreases the main current.

Abstract: Current differential protection is provided for a multi-terminal power apparatus, such as a power transmission line. Currents measured at each of the multiple terminals are used to calculate a differential current and a restraining current, which are then converted into a first equivalent current and a second equivalent current of an equivalent two-terminal power apparatus. In the equivalent two-terminal power apparatus, a differential current derived from the first and second equivalent currents is substantially equal to the differential current of the original multi-terminal power apparatus. Similarly, a restraining current derived from the first and second equivalent currents is substantially equal to the restraining current of the original multi-terminal power apparatus. The first and second equivalent currents may be used in an alpha plane analysis to determine whether or not to trip the multi-terminal power apparatus.

Abstract: The present invention discloses a short-circuit detection circuit and a short-circuit detection method. The short-circuit detection circuit detects whether an output node is short-circuited to a first predetermined level. A first switch circuit which is controlled by a control signal is coupled between the output node and a second predetermined level. The short-circuit detection circuit includes: a determination circuit, which is coupled between the output node and the second predetermined level, wherein when the determination circuit is enabled, it generates a determination signal according to whether the output node is short-circuited to the first predetermined level; and a second switch circuit, which generates a short-circuit detection signal according to the determination signal.

Abstract: In a driver, a clamping module executes a clamping task that clamps an on-off control terminal voltage to be equal to or lower than a clamp voltage for a predetermined time during charging of the on-off control terminal of the switching element. The clamp voltage is lower than an upper limit of the voltage at the on-off control terminal of the switching element. A measuring module measures a parameter value correlated with a sense current correlated with a current flowing between input and output terminals of the switching element. A limiting module discharges the on-off control terminal to limit flow of the current between the input and output terminals if the value of the parameter exceeds a threshold. A setting module variably sets a length of the predetermined time as a function of the parameter value during charging of the switching element's on-off control terminal.

Abstract: A current-limitation system for limiting a current through an DC connection in case of a fault occurring in a DC grid of which the DC connection forms a part is provided, as well as a method of operating a current-limitation system for limiting a current through an DC connection in case of a fault occurring in a DC grid of which the DC connection forms a part.

Abstract: A switch for a high-voltage direct current transmission path includes a vacuum circuit breaker for disconnecting the transmission path and a gas-insulated circuit breaker for disconnecting the transmission path. The gas-insulated circuit breaker is connected in series with the vacuum circuit breaker. A device is provided for building up a counter-current against the current in the transmission path for the purpose of reducing the current across the vacuum circuit breaker. The elements of the switch are actuated by a control device in such a way that the switch is switched off at or close to the zero crossing of the current.

Abstract: A power supply device comprising: a plurality of battery units each having a protective unit, an output voltage from the plurality of battery units being configured to energize an electric power tool; and a drive-limiting unit provided in a current path of the battery unit of each row, wherein each protective unit stops energization from the battery unit of its row by the drive-limiting unit provided in the current path of the battery unit of its row, when the battery unit of its row has an error.

Abstract: A video circuit employed in a video apparatus is configured for transmitting a video signal via an interface unit. The video circuit includes a display circuit and a compensation circuit. The display circuit switches the video apparatus into a video input mode in response to a user's operation, and blocks specific component of the video signal received from the interface unit. The compensation circuit adds a predetermined amount of direct current to the video signal.

Abstract: 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.

Abstract: A method and apparatus for composing a desirable trip curve, such as an I2*t trip curve, for an electrical protective device from at least one less desirable trip curve, such as an I*t trip curve. The method is accomplished by defining a selected parameter of the desirable overload trip curve and defining the selected parameter as a function of one or more monitored input values, such as current, trip class or phase unbalance, and modulating the selected defined parameter value between a maximum boundary trip curve and a minimum boundary trip curve. The modulated parameter is used to adjust the less desirable trip curve such that it has the characteristics of the desired trip curve. The method is implemented by one or more electrical circuits (filter circuits) representing the less desirable trip curve(s) and composing an output signal representing the desirable trip curve by modulating between the one or more electrical circuits.

Abstract: A first overcurrent detection unit detects whether a drain-source voltage of an output transistor is greater than or equal to a first reference value and outputs a first detection signal. A second overcurrent detection unit detects whether an output current passing through the output transistor is greater than or equal to a second reference value and outputs a second detection signal. When receiving the first detection signal indicating that the drain-source voltage is greater than or equal to the first reference value, a latch circuit latches the second detection signal; when receiving the first detection signal indicating that the drain-source voltage is smaller than the first reference value, the latch circuit outputs the second detection signal without latching it. Based on the output of the latch circuit, the drive circuit controls the output transistor to either turn it off or turn it on and off alternately.

Abstract: An overcurrent protection device comprises a maximum-allowed-current unit and a power switch. The maximum-allowed-current unit determines a maximum allowed current in real-time. The maximum allowed current is determined at least partially on an instantaneous level of a load voltage. The load voltage is a voltage across a load to be powered. The power switch is connectable with a switch input to a voltage supply and with a switch output to the load, for providing power to said load. The power switch has a conductive state and a nonconductive state, and is arranged to assume the nonconductive state in response to an indication that a current through the power switch is exceeding the maximum allowed current. A method of operating a power switch is also described.

Abstract: An overcurrent protection device comprises a maximum-allowed-current unit and a power switch having a conductive state and a nonconductive state. The maximum-allowed-current unit determines a time-dependent maximum allowed current according to a supply voltage. The power switch assumes the nonconductive state in response to an indication that a current through the power switch is exceeding the maximum allowed current. A method of operating a power switch is also described.

Abstract: A method for protecting an electrical energy distribution box (BODP) equipped with a supply current distribution bar (BDP) intended to be connected between an electrical energy source (G) and loads (Q1, Q2, Q3 . . . Qn) to be supplied, comprising detecting an electrical fault in the distribution box (BODP). The detection step comprises: —measuring a supply current drawn on said supply current distribution bar (BDP) by the electrical energy source (G), —measuring load currents distributed from the distribution bar to each of the loads (Q1, Q2, Q3 . . . Qn), and continuous processing of said measurements of current in the course of which the supply current and the load currents are compared with load current threshold values so as to detect overloads.

Abstract: Methods and systems are provided for sensing electrical faults. The system includes a current sensor disposed between a battery and at least one electrical load. The current sensor is capable of sensing electrical current flowing from the battery to the load at a sensitivity sufficient to detect a current transient. The system also includes a controller in communication with the current sensor. The controller is capable of comparing the sensed current transient to a predetermined current transient for the load and signaling a fault when the sensed current transient and the predetermined current transient vary by a predetermined amount.

Abstract: The present invention provides an apparatus for easily detecting an abnormal status of power generation of a solar cell panel in a solar cell power generation system having the power generation of 1 MW or higher. The present invention provides an abnormality detecting apparatus for a solar cell power generation system including a plurality of solar cell strings each having a plurality of solar cell modules connected to each other in series and a backflow preventing diode connected to a power output terminal of each of the solar cell strings, characterized in that the abnormality detecting apparatus further includes measuring means for measuring a current flowing in the backflow preventing diode; and that the measuring means is supplied with electric power from both terminals of the backflow preventing diode.

Abstract: Methods, systems, and apparatus for determining whether an accessory includes particular circuitry. A host device may measure a first voltage and a second voltage received from an accessory, where the voltages are provide through the accessory from a power source. Before measuring the second voltage, the host device may send an instruction to the accessory instructing the accessory to alter an impedance of the power path between the power source and the host device, and the host device may draw at least a threshold amount of current from the power source via the accessory. The host device may then determine whether the accessory includes particular circuitry based on the relationship between the first voltage and the second voltage.

Abstract: A circuit protection device for monitoring a current flowing from an electrical distribution line through a trip mechanism to a load includes an input conductor configured to receive a current signal from a sensor. At least one resistor is arranged to receive the current signal from the input conductor, and provides a voltage signal proportional to the current signal. The circuit protection device includes a control circuit coupled in parallel with the resistor and a power supply that receives the current signal from the resistor and supplies power to the control circuit based on the current signal. The control circuit is configured to receive the voltage signal and determine an amplitude of the current flowing through the trip mechanism based on the voltage signal. The control circuit is also configured to determine whether a predetermined current threshold is exceeded and to generate a control signal to activate the trip mechanism.

Abstract: A line current differential protection system that uses an external time reference continues providing protection to a power apparatus upon the loss of the external time reference. An external time reference synchronization mode and a channel based synchronization mode may be selectively applied on a per channel basis such that only those channels in the system that are not guaranteed to stay symmetrical use external time reference synchronization.

Abstract: A switching circuit 1 comprises a transistor 11; a detection resistance 12, connected to the transistor 11, for receiving a current flowing through the transistor 11; an overcurrent detection circuit 13 for detecting from a voltage between both ends of the detection resistance 12 whether or not the current flowing through the transistor 11 is an overcurrent; a control circuit 15 for switching control of the transistor 11, the control circuit restricting the switching control when the overcurrent detection circuit 13 detects that the current flowing through the transistor 11 is the overcurrent; and a level-shift circuit 14, disposed between the overcurrent detection circuit 13 and the control circuit 15, for level-shifting a signal from the overcurrent detection circuit 13 and transmitting the level-shifted signal to the control circuit 15; the overcurrent detection circuit 13 having a ground potential different from that of the control circuit 15.

Abstract: Transformer differential protection is provided by measuring a plurality of currents corresponding to a first set of windings and a second set of windings of a transformer, and compensating the currents based on their respective flows through either the first set of windings or the second set of windings. The compensated currents may be intentionally augmented to compensate for magnetizing inrush and/or stationary overexcitation conditions associated with the transformer. Augmentation based on stationary overexcitation, for example, may be based on either harmonic restraint or an addition of a V/Hz ratio to a restraining signal. A complex current ratio is calculated corresponding to the plurality of compensated currents. The complex current ratio may be based on a two-terminal equivalent power apparatus. Then, an alpha plane analysis is applied to the complex current ratio. Based on the alpha plane analysis, a power apparatus that includes the transformer is selectively tripped.

Abstract: A method of digital sampling of a current or group of currents in an electrical system including using in the sampling, sufficient bandwidth to reconstruct the amplitude and phase of a synthesized power frequency and its harmonics and a fundamental carrier frequency of switching electronics and modulation sidebands.

Abstract: A load circuit protective device calculates increasing temperature of wire of a load circuit with a first predetermined sampling period (dt1) determined by a clock signal for normal operation when a semiconductor relay (Q1) is on to estimate the temperature of the wire. The temperature of the wire is therefore estimated with high accuracy. Moreover, when the semiconductor relay (Q1) is off, the load circuit protective device calculates decreasing temperature of the wire of the load circuit with a second predetermined sampling period (dt2) to estimate the temperature of the wire. The second predetermined sampling period (dt2) is determined by a clock signal for power-saving operation and is longer than the first predetermined sampling period (dt1). Accordingly, the calculation times of the temperature can be reduced, and the power consumption is therefore reduced.

Abstract: A load circuit disconnection detector includes: a current sensor (16) for detecting current flowing through a wire (W1) of a load circuit; and a protective device (100) for estimating temperature of the wire (W1) based on the detected current and forcibly turning off a semiconductor switch (Q1) if the estimated temperature of the wire reaches threshold temperature. The load circuit disconnection detector determines that there is a connection failure in the load circuit if a temperature increase calculated by a temperature calculation unit (24) is zero even a predetermined time (P1) after the semiconductor switch (Q1) is turned on.

Abstract: Apparatus for increasing the efficiency of a starter battery for a starter motor of an internal combustion engine in a battery pack arrangement with one or more lithium based cells. The invention includes a solid state switching configuration for high powered battery systems for protecting against over-charging, over-discharging and short circuiting of batteries, especially starter batteries for internal combustion engines.

Abstract: The present invention relates to a device and a method for reliably securing an electric line with a controllable switching element, wherein the device and the method can be easily adapted to the properties of an electric line. The device comprises a controllable switching element (110, 610) that is designed to take on at least two states, specifically a first state with a first resistance and a second state with a second resistance that is lower than the first resistance.

Abstract: An electric switch is disclosed, in particular an electric circuit breaker. In at least one 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 reference 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 apparatus for an electric power tool includes a detection unit, a determination unit, a protection unit, a calculation unit, and a notification unit. The calculation unit calculates a time-equivalent value representing a remaining time until a load condition of a battery reaches an overload state, in which the protection unit interrupts a discharge path, based on the result of the detection by the detection unit. The notification unit notifies a user of the electric power tool of a remaining time until the protection unit interrupts the discharge path based on the time-equivalent value calculated by the calculation unit.

Abstract: A circuit and method protect switching devices from alternating current overload. By protecting the switching devices from AC overload, the reliability of the equipment using the switching devices is improved, cost for repair is decreased and information regarding the cause of the AC overload is available.

Abstract: An overcurrent detection circuit for a DC-to-DC power converter is disclosed. The overcurrent detection circuit includes a dynamic reference unit for outputting a dynamic reference signal, a load current measurement unit for measuring a load current of the DC-to-DC power converter to output a measurement signal, and a first comparator including a positive input terminal coupled to the load current measurement unit, a negative input terminal coupled to the dynamic reference unit and an output terminal coupled to an overcurrent protection device for outputting an overcurrent protection signal to activate the overcurrent protection device when the measurement signal is greater than the dynamic reference signal.

Abstract: A device for operating a relay to selectively provide power from a power supply to a load. The device determines an activation switching point for activating the relay such that inrush current resulting from the activation is minimal. The device also determines a deactivation switching point for deactivating the relay such that backrush current is minimal. The switching points are determined with respect to a voltage waveform of the supply power. The device varies the timing of the operation of the relay with respect to the voltage waveform and monitors the inrush or backrush current resulting from each timing until a minimum inrush or backrush current is found. The device stores these times in memory for subsequent operation of the relay. To further reduce inrush and backrush currents associated with inductive loads, the device activates and deactivate the relay on opposite half cycles.

Abstract: A gate driving circuit for driving a power semiconductor element can include a MSINK that is an n-channel metal-oxide silicon field-effect transistor (MOSFET) with a low resistance value for rapidly drawing out the charges accumulated on the gate of an insulated gate bipolar transistor (IGBT), and a MSOFT that is an n-channel MOSFET with a high resistance value for slowly drawing out the charges. By shifting the time for turning ON of these MOSFETs, soft interruption can be performed rapidly and surely when overcurrent or short circuit current flows in the IGBT. Therefore, device breakdown is minimized or avoided and noise generation is suppressed.

Abstract: A current sensor includes a magnetic balance sensor and a switching circuit. The magnetic balance sensor includes a feedback coil which is disposed near a magnetic sensor element varying in characteristics due to application of an induction field caused by measurement current and which produces a canceling magnetic field canceling the induction field. The switching circuit switches between magnetic proportional detection and magnetic balance detection. The magnetic proportional detection is configured to output a voltage difference as a sensor output. The magnetic balance detection is configured to output, as a sensor output, a value corresponding to current flowing through the feedback coil when a balanced state in which the induction field and the canceling magnetic field cancel each other out is reached after the feedback coil is energized by the voltage difference.

Abstract: A multi-terminal power line protective relay system is provided, which divides a power transmission line having four or more terminals into two or more power line sections composed of three adjacent terminals and portions of the power transmission line lying among the three adjacent terminals and one of the three adjacent terminals being shared by two adjacent power line sections, and includes protective relays at the respective terminals including a current-driven differential protective relay element for detecting a fault occurring in a power line section through current-differential calculation by using measured currents, inter-terminal communication channels linking two protective relays at two different terminals; and intra-terminal communication channels linking two protective relays at each shared terminal.

Abstract: A method for detecting the state of at least one element of a circuit comprising one or several loads, powered by an A.C. voltage and in series with at least one first switch. The state of the element is obtained by analyzing, at several times in a period of the A.C. voltage, the amplitude of a current sampled from the junction point of the load and of the first switch.

Abstract: A device, such as an intelligent electronic device (IED), provides a monitoring and protective function for a power system. The protective function uses stimulus acquired from the power system to detect power system conditions and to take one or more protective actions responsive thereto. The device may detect arc flash events in the power system based upon electro-optical and/or current stimulus measurements obtained therefrom. The stimulus measurements may be recorded to use in metering, validation, identifying detector misoperation, and/or event oscillography.

Abstract: A device, such as an intelligent electronic device (IED), provides a monitoring and protective function for a power system. The protective function uses stimulus acquired from the power system to detect power system conditions and to take one or more protective actions responsive thereto. The device may detect arc flash events in the power system based upon electro-optical and/or current stimulus measurements obtained therefrom. The stimulus measurements may be recorded to use in metering, validation, identifying detector misoperation, and/or event oscillography.

Abstract: A proximity detection circuit is contemplated to detect connection of a cordset to a vehicle charging system or connection of another device to some other electrical circuit where it may be desirable to facilitate detection. A short protection circuit may be included as part of the proximity detection circuit to facilitate disconnection in the event of a shorter other condition where undesirable currents and/or voltages may be propagated to other systems of portions of the vehicle charging system.

Abstract: A protection device is to be associated in an electrical circuit (3) with a current-breaker device (20) including at least one pair (2) of contacts. The protection device includes a measuring device (1.1) for detecting a fault in the electrical circuit, at least one pair (6) of trigger contacts adapted to assume a closed or open position and to energize a coil for operating the pair (2) of contacts of the current-breaker device (20), and a control device (1.2) for commanding closing the pair (6) of trigger contacts in the event of detecting a fault, launching a time-delay and opening the pair of trigger contacts in the event of disappearance of the fault at the end of the time-delay, and barring opening pending operator intervention if the fault persists at the end of the time-delay.

Abstract: An electric distribution system includes at least one feeder and a protection and control system. The feeder includes at least one segment including a first end and an opposing second end. The protection and control system includes a protective device and an electric current measuring device coupled to the segment proximate each end. The system further includes at least one processor coupled in communication with the electric current measuring devices. The at least one processor is programmed to determine a difference between a synchronized first electric current measured proximate the first end and a synchronized second electric current measured proximate the opposing second end and determine a switching condition of the protective devices as a function of the difference between the synchronized first and second electric currents.

Abstract: Disclosed herein is a power supply device. The power supply device includes a conversion unit converting an applied voltage into a predetermined level, a switching unit performing an opening operation or a closing operation to control a current flowing in the conversion unit, a sensing unit sensing an occurrence of overcurrent when a voltage applied to the switching unit is equal to or larger than a reference voltage set in advance, and a control unit performing a protection operation when the overcurrent is sensed again within a protection time set in advance after a predetermined time is delayed from the time at which the overcurrent is sensed, so that malfunction due to noise is prevented.