Abstract: A system and method for differential protection of a transformer under geomagnetically induced current (GIC).

Abstract: A system includes three switches each having a single pole and dual throws. The respective single pole is on a supply side of the each respective switch. The dual throws are on a load side of each respective switch, and include a respective normally open (NO) throw and a respective normally closed (NC) throw. A first voltage detector is connected from the single pole of the first switch to the NC throw of the third switch. A second voltage detector is connected from the single pole of the second switch to the NC throw of the first switch. A third voltage detector is connected from the single pole of the third switch to a NC throw of the second switch.

Abstract: A method for providing grid-forming control of an inverter-based resource includes receiving a negative-sequence voltage feedback of the inverter-based resource. The method also includes receiving at least one negative-sequence feedback signal of the inverter-based resource. The method also includes determining, via a negative-sequence regulator, one or more control signals indicative of a desired negative-sequence impedance of the inverter-based resource using the at least one negative-sequence feedback signal. Further, the method includes generating, via the negative-sequence regulator, a control command for the inverter-based resource based on the one or more control signals. Moreover, the method includes controlling the inverter-based resource based on the control command to achieve the desired negative-sequence impedance of the inverter-based resource.

Abstract: The present disclosure relates to querying data cores for data items that correspond to a specified time range. Probabilistic data structures corresponding to associated data cores are used to filter the plurality of data cores to identify a subset of data cores that contain data items corresponding to the specified time range. Only the subset of the plurality of data cores determined to contain relevant data items are searched.

Abstract: A method for determining when a connection of a power system to a grid has been disconnected. The method includes the power system supplying a first amount of reactive power to the grid to which the power system is connected, and the power system determining if there is a frequency change within the grid. This includes if the frequency change does not exceed a predetermined threshold, the power system supplying a second amount of reactive power to the grid, and if the frequency exceeds a predetermined threshold, the power system supplying a first amount of reactive power to the grid.

Abstract: A mobile application includes a motive power circuit, the motive power circuit including a power storage device and an electrical load, where the power storage device and the electrical load are selectively electrically coupled through a power bus; a power distribution unit (PDU) electrically interposed between the power storage device and the electrical load, where the PDU comprises a breaker/relay positioned on one of a high side and a low side of the power storage device; wherein the breaker/relay includes a fixed contact electrically coupled to the power bus, a moveable contact selectively electrically coupled to the fixed contact, an armature operationally coupled to the moveable contact, and a biasing member biasing the armature.

Abstract: A system and method for feeder protection in an electrical power network nodal point including at least three feeders. In the system and the method it is executed in an intelligent electronic device reserved for the feeder, on the basis of the at least one measured electrical quantity actual in the respective feeder, at least one first protection function monitoring a power system related condition of the respective feeder, as well as in a central intelligent electronic device, for at least one feeder, at least one second protection function monitoring the same power system related condition of the feeder. Furthermore the central intelligent electronic device is configured to further execute for the at least one feeder, on the basis of the at least one measured electrical quantity actual in the other feeders connected to the same nodal point, at least one third protection function monitoring the same power system related condition of the feeder.

Abstract: An alternating current circuit breaker has a first galvanic separation switch and a bypass switch in a live line, a second galvanic separation switch in the neutral line, and a semiconductor switch element connected parallel to the bypass switch. A processing unit is arranged to control the first and second galvanic separation switch, the bypass switch and the semiconductor switch element. A short circuit and overcurrent detection unit is connected to the processing unit for determining a short circuit situation or overcurrent situation. The processing unit is further arranged to execute a reclosing attempt after a certain time period after tripping of the circuit breaker, wherein the time period is dependent on the type of situation causing the tripping of the circuit breaker.

Abstract: Disclosed herein are representative embodiments of methods, apparatus, and systems for facilitating operation and control of a resource distribution system (such as a power grid). Among the disclosed embodiments is a distributed hierarchical control architecture (DHCA) that enables smart grid assets to effectively contribute to grid operations in a controllable manner, while helping to ensure system stability and equitably rewarding their contribution. Embodiments of the disclosed architecture can help unify the dispatch of these resources to provide both market-based and balancing services.

Abstract: The circuit breaking system contains a power circuit whose voltage is greater than 600 volts, at least a circuit breaking device, at least a current detection device, a current reduction unit, at least an actuation device, and a linking device. The circuit breaking system is applicable to a high or ultra-high voltage power circuit, and the power circuit is interrupted through purely mechanical means without additional electricity provision. Even when there are major disasters that existing protection means fails, the present invention can still function and provides a trip free, ultimate self-protection mechanism so that a power system can be readily reset.

Abstract: The reclosing control device configured to perform a reclosing control in case of a fault in a transmission line. Further, the reclosing control device includes a voltage detection unit configured to detect a faulted phase voltage waveform and extract a harmonic component contained in the faulted phase voltage waveform; a HR calculating unit configured to calculate ratio values between even harmonics and odd harmonics based on the extracted harmonic component; and a reclosing control unit configured to determine whether or not an arc is finally extinguished based on the calculated ratio value and perform a reclosing control depending on a result of the determination.

Abstract: A substation instrument control system is disclosed. The substation instrument control system includes a plurality of transformers that generate a plurality of waveform signals representing electric properties of a substation instrument main body. A merging unit is communicatively coupled to the plurality of transformers and includes a signal processing unit and a control unit. The signal processing unit receives the plurality of waveform signals from the plurality of transformers and converts the plurality of waveform signals to a digital signal. The control unit controls operation of the signal processing unit using a setting data. An intelligent electronic device is communicatively coupled to the merging unit and receives the digital signal from the merging unit.

Abstract: The method for adjusting a hearing device (11) to the hearing preferences of a user of the hearing device comprises a) adjusting at least one of N parameters (P1, P2), preferably with 2?N?4; b) obtaining a gain model (G), which is identical with the output of a fitting rationale (F) applied to a model audiogram (A), wherein the model audiogram depends on the N parameters and is independent of possibly existing audiogram values measured for the user; and c) using the gain model (G) or a gain model derived therefrom in said hearing device (11). Preferably, the model audiogram (A) is an approximation to an audiogram occurring in a pre-defined empirical sample of individual audiograms. The user preferably carries out the method by himself and without external equipment. A corresponding arrangement (1) is disclosed, too. A simple and efficient hearing device fitting can be achieved.

Abstract: A distributed busbar protection system using time-stamped data gathered from measurement devices in an electrical power system bus arrangement by respective intelligent electronic devices (IEDs). The IEDs may derive the timestamp information from a clock or other time source, which may be synchronized to a common time source and/or an absolute time. The time-stamped measurement data may be used by a protection device to monitor and/or protect the electrical power system. The protection device may include a real-time vector processor, which may time-align the time-stamped data, determine one or more bus differential protection zones, and implement a differential protection function within each of the protection zones. One or more protective control signals may be transmitted to the IEDs to trip the corresponding breakers and clear the bus fault.

Abstract: The reclosing control device configured to perform a reclosing control in case of a fault in a transmission line. Further, the reclosing control device includes a voltage detection unit configured to detect a faulted phase voltage waveform and extract a harmonic component contained in the faulted phase voltage waveform; a HR calculating unit configured to calculate ratio values between even harmonics and odd harmonics based on the extracted harmonic component; and a reclosing control unit configured to determine whether or not an arc is finally extinguished based on the calculated ratio value and perform a reclosing control depending on a result of the determination.

Abstract: A voltage clamping circuit includes a current source having a fixed current source and a variable current source and a variable resistor receiving current from the current source. The variable resistor varies its resistance in response to an environmental operating condition. The voltage clamping circuit also includes an amplifier configured to compare a sensor node voltage with a reference voltage, the sensor node voltage being in communication with the voltage drop across the variable resistor. The amplifier is configured and connected to provide a control output to control the variable current source to modify current output from the variable current source to at least in part prevent the sensor node voltage from exceeding a reference voltage when certain operating conditions are present.

Abstract: A device and method for dynamically determining an impedance of a network is disclosed. The device includes at least a processing system for measuring a network voltage and network current when said network is determined to be in a first state, measuring a network voltage when said network is determined to be in a second state, estimating said impedance value dependent upon said measured voltages and current, adapting said estimated impedance based on at least one prior impedance value and storing at least said adapted impedance.

Abstract: In a method and system for protecting a battery being charged by an electrical device, a current flowing through a cell stack of the battery is measured. If the measured current is greater than a predefined value the battery is isolated from the device. If subsequent current measurements made within a predefined time interval indicate that the measured current is less than or equal to the predefined value then the battery is recoupled to the device. If the measured current remains greater than the predefined value during the predefined time interval then a fuse is blown and the battery is disabled.

Abstract: A method of detecting the presence of an unsafe line condition at a power metering device is disclosed. The method comprises the steps of determining if a disconnect switch is in the open position, and measuring a first voltage at a first load contact. The method measures a second voltage at a second load contact and determines if the first voltage is greater than a first voltage threshold or less than a second voltage threshold. The method further determines if the second voltage is greater than the first voltage threshold or less than the second voltage threshold. The method indicates that an unsafe condition exists if either the first voltage is greater than the first voltage threshold, or first voltage is less than the second voltage threshold or the second voltage is greater than the first voltage threshold or the second voltage is less than the second voltage threshold, when the disconnect switch is in the open position.

Abstract: An apparatus is disclosed for monitoring usage of multiple electrical devices. The apparatus comprises multiple non-invasive current sensors for sensing current in respective conductors associated with the electrical devices. Such conductors may for example be the electrical power supply leads to the devices. The apparatus further includes multiple analogue to digital conversion functions for digitizing the output from the respective current sensors. A microprocessor is arranged to receive the digitized current sensor and is programmed to create usage data relating to the respective electrical devices. Such usage data may include cumulative elapsed running time. The microprocessor has an associated memory in which the usage data is stored in association with corresponding data identifying the electrical devices. The system further includes an interface through which the usage and identifier data are extractable, to provide usage information for the respective electrical devices.

Abstract: An apparatus for anti-islanding protection of a distributed generation with respect to a feeder connected to an electrical grid is disclosed. The apparatus includes a sensor adapted to generate a voltage signal representative of an output voltage and/or a current signal representative of an output current at the distributed generation, and a controller responsive to the signals from the sensor. The controller is productive of a control signal directed to the distributed generation to drive an operating characteristic of the distributed generation out of a nominal range in response to the electrical grid being disconnected from the feeder.

Abstract: A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When the integration exceeds a predetermined value, the source is considered unreliable. Also in a preferred arrangement, a determination is made as to whether or not the disturbance is a downstream fault condition. For example, this is useful for applications where a transfer is made from a first source to a second source when predetermined disturbances are detected. In this manner, the transfer of the load to a second source is avoided which would continue the supply of the downstream fault. Additionally, the arrangement distinguishes between various degrees of disturbances to permit appropriate response based on the severity and type of disturbance. For example, a first immediate response, i.e.

Abstract: A method of monitoring and controlling a power distribution system is provided. The power distribution system includes a plurality of circuit breakers, a plurality of node electronic units, and wherein each associated circuit breaker is electrically coupled with each respective node electronic unit. The system also includes at least one digital network, and at least one central control processing unit (CCPU) wherein each CCPU includes a first power system global information set, and each CCPU is communicatively coupled to the plurality of node electronic units. The method includes transmitting at least one digital message from each node electronic unit to each CCPU over a respective network, determining an operational state of the power distribution system from the digital message, and transmitting at least one multicast message from each CCPU to each node electronic unit such that the circuit breakers are operable from each CCPU.

Abstract: An LCD module having a lamp cover with an improved structure, includes a lamp; a lamp cover which is bent once so as to define an upper plate and a side plate thereof, and which covers an upper portion and side portion of the lamp with a lower portion of the lamp being opened, the lamp cover being arranged to reflect a light produced from the lamp; a light guide plate having an upper surface and a side surface thereof corresponding to the upper and side plates of the lamp cover, respectively, the light guide plate being arranged to a side of the lamp cover, the light guide plate receiving a light produced from the lamp through the side surface thereof and transmitting the light toward the upper surface thereof; and a rear reflector plate arranged at a lower surface of the light guide plate and which is extended toward the lower portion of the lamp, the rear reflector plate directing toward the upper surface of the light guide plate a light being leaked through the lower surface of the light guide plate.

Abstract: A liquid crystal display device which can, even in case where a vibration and an impact such as drop are exerted on a note type computer in which the liquid crystal display device is mounted, prevent a fitting portion for fixing a case body and an LCD cover from disengaging and a pawl portion of the fitting portion from being damaged, and which has fixing means whose maintenance performed by detaching the case body and the LCD cover is easy. A frame-like cushion material whose internal dimension is smaller than an external dimension of a liquid crystal display element and which is formed by using a material excellent in its elastic coefficient and having a high friction factor is mounted inside the case body 4 of the liquid crystal display device, and the liquid crystal display element is fitted into the frame.

Abstract: A circuit protection system is provided that utilizes a single state definition for each of the zones of protection of the circuit to increase computational efficiency. Multiple zone protective functions can be performed on a single zone of protection and can reference the single state definition.

Abstract: A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When the integration exceeds a predetermined value, the source is considered unreliable. Also in a preferred arrangement, a determination is made as to whether or not the disturbance is a downstream fault condition. For example, this is useful for applications where a transfer is made from a first source to a second source when predetermined disturbances are detected. In this manner, the transfer of the load to a second source is avoided which would continue the supply of the downstream fault. Additionally, the arrangement distinguishes between various degrees of disturbances to permit appropriate response based on the severity and type of disturbance. For example, a first immediate response, i.e.

Abstract: To shorten the recovery time of a line driver (1) after an overvoltage on its output terminal (3), a current generating device (5) senses a voltage difference between the output voltage of the line driver (1) and its supply voltage (UB) plus a threshold voltage (UT′), and supplies a current (I) that is proportional to the sensed voltage difference up to a maximum current to the output (3) of the line driver (1) to raise its potential to thereby shorten its recovery time.

Abstract: The invention in the simplest form is a method and apparatus for reliably protecting against island situations with one or multiple power sources connected to an electric distribution grid. The method and apparatus detects variations in the voltage and frequency of the grid. An observed change in grid voltage causes a change in output power that is sufficient to cause an even larger change in grid voltage when the utility AC power source is disconnected. An observed change in grid frequency causes a change in phase or reactive output power that is sufficient to cause an even larger change in grid frequency. If several shifts in voltage or frequency happen in the same direction, the response to the change is increased in an accelerating manner.

Abstract: A switched-transconductance circuit used in a multiplexer forming a part of a crosspoint switch includes integrated T-switches that are enabled when the transconductance stage is not enabled. The transconductance stage is selectively enabled by controlling a split-tail current source driving a differential pair of input transistors. When the transconductance stage is disabled (1) a pair of switches connected between the collectors of the differential pair and a positive voltage supply node are enabled, (2) a pair of cascode transistors connected between the collectors of the differential pair and output leads of the circuit are reversed biased by the positive supply voltage passing through the pair of switches, and (3) a switch is enabled between a common emitter node of the differential pair and a low impedance constant voltage node.

Abstract: A solid state power switching circuit for alternating current loads, in which operating power for the circuit is diverted from the switched current during power stealing intervals self-synchronized with the alternating current waveform. During periods in which current to the load is commanded, a load current switch is maintained in a low impedance state except for the duration of a short power stealing interval each half-cycle of the supplied alternating current. Self-synchronization is achieved with a current detector which senses whether or not the magnitude of the current diverted during each power stealing interval exceeds a current threshold, and pulse generator logic which shifts the power stealing intervals in time relative to the alternating current waveform in response to the previously sensed current magnitude.

Abstract: A differential shunt-type detector circuit includes a voltage-regulator component series combined with one or more than one shunt components in a circuit connected in parallel with, for example, a thermostatic switch element, such that when the terminal voltage of the shunt components is within the voltage-regulator component work range, no shunt or distribution or shunting effect is generated by the voltage-regulator component, while when the terminal voltage exceeds the voltage-regulator component work range, a shunt or distribution effect is obtained.

Abstract: Automatic reclosing apparatus for a DC feeder circuit breaker connectable between a main power bus and a feeder line, including a transducer connectable to the feeder line and a return bus for producing an output signal that corresponds to voltage on the feeder line; and a programmable controller connectable to the breaker for reclosing the breaker when a fault condition is absent and for preventing breaker closure when a fault condition is present; the controller being coupled to the transducer for detecting zero offset and full scale calibration of the transducer output signal. The apparatus can also determine negative return voltage and use such determination to improve accuracy of a load measurement test. The zero offset and full scale calibration functions can be used to implement open and short circuit tests of the apparatus.

Abstract: A circuit for protecting electronic equipment such as computers, laser printers, fax machines, and the like from damage due to electrical transients associated with a temporary power interruption is connectable between a source of A.C. power and the electronic equipment. The circuit disconnects the equipment from the power source during a temporary power outage and maintains the equipment disconnected from the A.C. power until transients in the line voltage have abated. The circuit reconnects the equipment to the A.C. power source after a preselected time delay from the initial power interruption. The circuit keeps track of time during a power interruption without the use of batteries.

Abstract: A power cutoff circuit is added to the protector network disclosed in U.S. Pat. No. 4,675,772 so that when an interruption in power occurs, at least one suppressor remains connected to a load even though a source is disconnected from the load. In one embodiment, the power circuit includes a control circuit connected to the supply lines between an "upstream" suppressor and a filter portion of the network.

Abstract: An all solid state timer-controller for the timed, sequential application of electrical current to loads within a circuit at high amperage, the circuit finding utility in the application of electrical current to de-icers employed aboard aircraft.

Abstract: A protective relay for a transformer issues a relay tripping command when the differential current that is the difference between currents in the primary and secondary windings of the transformer has a magnitude larger than the specified value and, at the same time, when the differential current includes the fifth harmonic component less than the specified value. Another cause of tripping signal generation is the differential current value processed to have a certain timer characteristics.

Abstract: An overvoltage protection circuit for communications systems for protecting equipment from power crosses on electric utility lines. A timed latch circuit is used to activate a plurality of steering SCR's which crowbar the overvoltage. The utilization of a latch circuit to activate the steering arrangement, instead of the conventional technique of using actual overvoltage line current, allows smaller devices to be used, thus reducing both circuit size and circuit power dissipation.

Abstract: A technique is disclosed for protecting against electrocution or shock resulting from contacting an exposed conductor which is connected to a power supply. The flow of power to the conductor, whether DC or AC, is periodically interrupted and during the interruption, contact between a body and the conductor is sensed. If the body is not contacting the conductor, power is restored, but if the body is contacting, the interruption is maintained. The circuit may also distinguish between contact with the body and contact with an electrical device which receives power from the conductor. The electrical device includes a barrier circuit, such as a diode, which switches to an electrical state, such as a high impedance state, when power is interrupted. Because the electrical characteristics of the barrier circuit, such as its capacitance, differ from those of a body, the circuit is able to detect contact with a body.

Abstract: A reclosing system for d-c feeder breakers in transit systems employing cars using a chopper type of regulated power is disclosed. The circuit includes voltage-sensing and load-measuring circuits which determine that there is no short circuit on the respective feeder line before the circuit breaker can be closed. The system operates in two sequential modes. The first is a voltage-sensing mode which, upon sensing a voltage on the feeder circuit greater than some given magnitude, will cause the closing of the feeder breaker. If this voltage is not sensed during the voltage-sensing mode, the circuit automatically goes into a load-measuring mode wherein a current is injected into the feeder circuit and the voltage drop caused by the injected current is monitored. If a sufficiently high voltage is produced, which indicates that the feeder circuit is free of a fault, the feeder breaker is closed.

Abstract: In order to prevent excessive voltages originating in customer owned terminal equipment from creating a hazardous condition in an associated telephone line, a protective circuit is connected between the equipment and the line. This circuit responds to an unbalanced current flow by disconnecting the equipment from the line and providing a local path to ground for the current. The circuit remains activated as long as the unbalanced current flow continues and reconnects the equipment to the line only when the current flow ceases.

Abstract: Telephone terminal equipments connected to the network through the device described herein are prevented from applying potentially human-hazardous voltages or currents to the network. The device includes a pair of bifilar relay coils, one in each connection to the central office. These operate an associated relay contact only when an unbalanced voltage or current condition occurs on the customer leads. A circuit path is thus completed to operate a second relay, which opens the connection between the customer terminal leads and the network leads; and establishes a path to ground through its own coils for the current from the unbalanced source. Means are included for assuring that the fraction of hazardous voltage appearing across the second relay remains essentially constant in the frequency range of 17 to 60 hertz. Only removal of the unbalanced current can release the relay and restore the network connection.

Abstract: High-voltage high-power, multiphase electrical installation comprising, for each phase, at least two circuit fields that include, in each circuit field, a circuit breaker arranged between two current transformers, each of them discharging into the same load as the homologous current transformers of the other circuit fields having the same phase; isolating switches placed at the ends; earth isolators placed between the isolating switches and the current transformers. The magnetic circuit of the current transformers is crossed simultaneously by the conductor of the phase of the circuit field and by an auxiliary conductor connected; on the one hand, to a ground isolator and, on the other hand, to a ground point.

Abstract: Electrical equipment, such as telephone station apparatus, exposed to occasional, destructively high, voltage surges (e.g., lightning strikes) is protected by a device, placed in parallel with the equipment, including two electrodes defining a fixed narrow spark gap. Such a device is designed to spark over with each surge and to recover afterward, restoring the line to its original condition. The predominant failure mode of such devices is shorting across the narrow gap, due to electrode damage produced during the protective arcing mode. In the disclosed devices, the electrodes define a narrow region, determining the protective breakdown voltage, and a wider region, sustaining the major part of the electrode damage. Shortly after the initiation of the protective discharge in the narrow gap region, the discharge is forced into the wider gap region by the provision, in at least one of the electrodes, of a high resistance path at the narrow gap region.