1419 results about "Line current" patented technology

A single stage switch mode power converter receives a supply line voltage and a supply line current from a power supply line, and provides one or more regulated output voltages for a load, such as an amplifier. The power converter is operable to regulate the output voltage(s) using a controller that includes a voltage controlled current loop. The controller can enable substantially constant supply line current to be drawn from the power supply line by selectively allowing conduction of the supply line current through the power converter. A power factor of the supply line voltage and the supply line current may be optimized by the controller at medium to high power levels thereby maximizing the power provided to the switch mode power converter from the power supply line. Due to the adaptive nature of the controller, the power converter can operate over a wide range of supply line voltage.

An arc fault detector for detecting electric power lines includes a sensor for sensing the derivative of the current on the electric power line, a converter circuit for converting the derivative of the line current into first and second signals, the first signal responsive to positive step transitions of arc fault current, and the second signal responsive to negative step transitions of arc current, and a temporal detector for signaling the presence of an arc fault when one of the first and second signals follows the other within a predetermined time, or window, and in which a sequence of one of the signals following the other signal occurs in a second predetermined interval of time.

Floating electrically isolated active impedance modules are formed to attach to power transmission lines without breaking the lines such that the power line forms a secondary of the main transformer of the module. Each module includes an electrical energy storage device and a switching circuit, such as a single phase inverter, connected to the storage device and to the main transformer primary winding. The inverter can be controlled to couple a selected voltage to the transmission line through the main transformer primary winding which can provide effective positive impedance, negative impedance, or a voltage at or near phase quadrature with the line current. Many active impedance modules may be distributed over a power system grid to allow control of the impedance of the power lines in the grid and to steer power through the grid, with each module electrically isolated from ground and from other phase lines of the transmission system.

A circuit breaker (such as a miniature circuit breaker) that wirelessly communicates state and fault information to a main energy monitoring module. The wireless circuit breaker includes a transceiver and a power supply that harvests energy inductively from the line current conductor without the need for a connection to a neutral conductor. The wireless circuit breaker can be implemented in the same package as existing circuit breakers, eliminating the need to replace the panel when upgrading to a system that employs a main energy monitoring module. The wireless circuit breaker can also include an energy storage device for supplying power to the circuit breaker after it has tripped, allowing the circuit breaker to transmit information after a trip. The main energy monitoring module includes a processor and a gateway for evaluating and transmitting information received from the circuit breaker to other applications, such as webpages and smartphones.

A system for accurate measurement and monitoring of AC or DC electrical current flowing through electrical conductors includes one or more current sensors, a receiver, and one or more calibration signal generators (“CSG's”) that can be plugged into outlets or otherwise coupled to the conductors so as to add automated, time-varying calibration signals to the conductors, such as current pulses or pulse patterns. The sensors are placed on a circuit breaker panel, around a cable, or otherwise near the conductors. The receiver distinguishes the calibration signals by their timing, pulse patterns, frequencies, or other time-varying features, uses their known amplitudes to calibrate the sensitivity of each sensor to each conductor, and determines the current flowing in each conductor. Among other applications, the invention can monitor building current usage, CO and data center power usage and distribution, and power line current leakage, and can calibrate invasive and/or non-invasive current sensors.

An apparatus and method compensate for the sensitivity of at least one line current differential element of a first current differential relay providing differential protection for a transmission line of a power system during a single-phase pole-open condition. The apparatus includes a first delta filter configured to remove a first pre-fault current from a first fault current of the transmission line to derive a compensated first current phasor. The apparatus also includes a second delta filter configured to remove a second pre-fault current from a second fault current of the transmission line to derive a compensated second current phasor. The compensated first and second current phasors are provided to the at least one line current differential element to compensate the sensitivity of the at least one line current differential element.

Methods and apparatus for dimming light sources are described herein. In certain embodiments, a bias circuit selectively biases a solid state switch during a portion of half-cycle of a line voltage after a settable delay. In some embodiments, the delay of the bias circuit is adjustable by a user, which varies the amount of energy provided to a light source, and the light generated there from. A charge circuit biases the switch for a period of time in the event the bias circuit experiences an operating condition (a ringing current) that may cause the switch to become open during the half-cycle of the line current. As a result of the charge circuit, the light source coupled to the line current does not experience substantial flickering and is compatible with low power compact fluorescent lights. The dimmer can be combined with other components to form a light harvesting system.

A basement flood control system for use in a structure having a basement floor located below ground level and having a sump pit or other collection basin for gathering subterranean water. The system has two primary pump units operated with line current, a battery-operated back-up pump unit, and a sensor arrangement for sensing water level in the collection basin. A controller is connected to the sensor arrangement and the pump units for variously activating the pump units singly or in any combination responsive to the water level detected by the sensor arrangement.

The invention discloses a multi-terminal flexible DC grid DC line quick protection method and system based on single-terminal voltage. The method comprises the following steps: collecting the voltagesignals on the two sides of DC positive and negative line current limiting reactors in real time; forming a low voltage starting criterion; performing wavelet transform on the calculated line mode voltage on the current limiting reactors and calculating the wavelet transform modulus maximum; performing the data validity test and recording the size and the symbol of the first wavelet transform modulus maximum meeting the data validity condition; establishing the fault identification criterion to identify the fault based on the symbol and amplitude difference of the single-terminal voltage traveling wave wavelet transform modulus maximum; and constructing the fault pole identification criterion to identify the fault pole based on the size difference of the voltage traveling wave transient energy. According to the line protection method, the fault direction can be reliably and quickly identified under various initial fault conditions, and the transition resistance, the fault location andthe fault of the AC system and other factors have little influence on the protection criterion so as to have high reliability and sensitivity.

An apparatus and a method of detecting arc faults that have reduced susceptibility to nuisance tripping. The apparatus includes a current sensor, a differential current input sense circuit, a differential current (di/dt) characteristics sense circuit, an absolute current input sense circuit, an absolute current characteristics sense circuit, a power supply, a tripping circuit, a processing unit, and an electromechanical interface. The di/dt characteristics sense circuit provides information relating to the characteristic di/dt signature of a power line current. The absolute current characteristics sense circuit provides information relating to the absolute current waveform characteristics of the power line current. The processing unit correlates the di/dt characteristics to the absolute current characteristics to distinguish between electrical arc faults and nuisance loads, thereby reducing the susceptibility of the apparatus to nuisance tripping.

A low-voltage arc fault detection method comprises collecting current signals in a loop through a current sensor, obtaining fundamental frequency analog signals and high frequency analog signals, achieving accumulating calculation of the fundamental frequency analog signals and high frequency analog signals of power frequency cycle through an integrating circuit, an interrupt trigger and a timer, and further obtaining higher harmonic occupancy. According to the method, whether arc faults occur is judged by real-time monitoring of change characteristics of the line current higher harmonic occupancy and calculation of over-limit times of the higher harmonic occupancy, normal arc and fault arc which are generated by some special electric appliance loads and normal on-off action are distinguished by judging whether higher harmonic occupancy changes caused by the arc faults are periodic and judging occurring frequency, occurrence of the arc faults can be detected in real time, the method is not limited by an installing position, malfunction caused by disturbance of operating arc generated by normal circuit opening and closing and loads such as a switch power and a dust collector can be avoided well, and the reliability is high.

The invention relates to a ground electrode circuit grounding protective system of a high-voltage DC transmission system. The system is provided with two parallel ground electrode circuits respectively connected in series with a high-voltage DC breaker, sets an allowable range of current differences of two ground wires and an allowable range of the subtraction of the line current sum of the two ground wires from the line current difference of the two ground wires and then sequentially executes the following control program: (1), reading currents of the two ground wires; (2), judging and comparing whether an absolute value of the current difference of two ground wires is larger than the allowable range thereof, if the absolute value is not larger than the allowable range, returning to the step (1); if the absolute value is larger than the allowable range, (3) then, judging whether the subtraction of the line current sum of the two ground wires from the line current difference of the two ground wires is smaller than or equal to the allowable range; if the subtraction is smaller than or equal to the allowable range, returning to the step (1); and if the subtraction is not smaller than or equal to the allowable range, enabling the high-voltage DC breaker which is connected in series with the ground wire with larger line current to trip and terminate the program. The system can avoid the imbalance of the ground electrode circuits due to the failures of the ground electrode circuits and protects the caused DC transmission system to be closed down.

A modular surge protector is provided where only the number and types of modules needed are purchased and connected together by a fixed line current or a removable power supply outlet. Generally, the modular surge protector includes a power distribution module, which is connected to a source of line current and one or more power supply modules, which may be connected via an additional line current or may be attached by the use of a power supply outlet. Each of the power supply modules will have at least one power supply outlet and may also have a modem surge protector.

The present invention combines an air freshener that has a source of air freshening chemical with a fan that is controlled either by an optical device that senses light or a motion detector. When a light is turned on or motion is detected, the fan will be activated for a predetermined time period. In certain embodiments, the fan will stop turning after a predetermined time. Alternatively, the fan can continue to be powered until the light source is turned off, or all motion ceases, and only then either immediately shut down, or shut down after a predetermined time period. In certain preferred embodiments the source of air freshening chemical is disposed beneath the fan and allows fragrance to be delivered over time without the fan. The additional airflow provided by the fan causes more volatile fragrance chemicals to be removed from the source of air freshening chemical and admitted into the environment. The fan motor of the present invention is driven by a power source, such as batteries, AC line current or alternate sources such as solar cells. Preferably, a microprocessor controls the fan so that a “burst mode” is created by controlling the frequency and intensity of the pulses of air freshener that are emitted.

The invention provides a support vector machine based fault electric arc detection method, relating to the technical field of electric arc protection and solving the technical problem of improving fault electric arc identifying and judging accuracy. The method provided by the invention comprises the following concrete steps of: 1) acquiring current samples of circuits to be detected under different loads and working conditions; 2) normalizing the waveform of each current sample; 3) obtaining a test sample combination according to the normalized current samples; 4) dividing the test sample combination into a train set and a verification set; 5) calculating a kernel function parameter and a punishment parameter which have the highest prediction accuracy rate; 6) predicting each sample in the verification set; 7) training by utilizing different sample sets to obtain a weight matrix; 8) verifying the samples in the verification set by utilizing the weight matrix, and creating a detection model according to the verification result; and 9) identifying and judging the fault electric arc by utilizing the detection model. By applying the method provided by the invention, false operation of fault electric arc detection equipment under the action of an interference load can be effectively avoided.

Systems and methods for implementing line overload control via providing distributed series impedance are disclosed. One system, amongst others, comprises at least one distributed series reactor (DSR). Each DSR comprises a single turn transformer (SST) comprising two split-core sections (132), a winding (120), and an air-gap (138), the air-gap designed such that a magnetizing inductance is produced when the two split-core sections (132) are clamped around a conductor (108). Each DSR further comprises a contact switch (122) that short circuits the winding when the contact switch (122) is in a closed condition, a power supply (128) that derives power from conductor line current, and a controller (130) configured to open the contact switch when the conductor line current reaches a predetermined value, thus causing insertion of the magnetizing inductance into the conductor. The controller (130) may be further configured to close the contact switch (122) when the conductor line current drops below the predetermined value.

A method for achieving single-phase earth fault line selection of a small current grounding system is characterized in that a high-precision zero-sequence current transformer is adopted by each feeder line; a single-phase earth fault of the system is confirmed when the instantaneous value of the zero-sequence current i0 of any one feeder line exceeds a set threshold /I0 /; comparison is conducted on symbols of all loop circuits at the moment of threshold triggering, and data after the triggering do not participate in judgment; the symbol of a faulty line current is unique and opposite to the symbols of non-faulty line currents, and the number of non-faulty lines is larger than or equal to 2; when the symbols of all the currents are identical, a bus earth fault is confirmed. The method for achieving single-phase earth fault line selection of the small current grounding system is adaptable to three grounding modes, namely neutral non-grounding, arc suppression coil grounding and neutral point high resistance grounding, of the small current grounding system and is not affected by a grounding moment phase angle, system unreal grounding and TV disconnection, and correction operation can still be achieved when the zero-sequence voltage of a bus is reduced to be 10% of a phase voltage by a transition resistor.

A system and method for monitoring the remaining useable life, or “wellness,” of a contactor or motor starter, and for predicting impending faults of such a device, is disclosed. By monitoring actuating coil current, actuating coil voltage, line current, and/or line voltage, the present invention can calculate wellness metrics which, when compared to threshold values, may be used as indicators of remaining life and/or imminent failures. The invention also provides non-mechanical positive indications of proper closures and openings of contacts for safety interlocking.