7467 results about "Instrument transformer" patented technology

A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on / off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET's, some with fast body diodes. The MOSFET's are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET's. The timing of turning on / off is arranged so that the current drawn from the AC source is sinusoidal and matches the phase of the sinusoidal AC source.

Apparatus and method for measuring current drain and reporting power consumption using current transformer with primary windings made of low ohmic alloy, enabling the use of the secondary coil to power the sensing and reporting circuits eliminating the power wasted by AC-DC power adaptors used for the current sensors. The saving is substantial as the current sensors will not drain a current when the AC outlets are disconnected from a load or when the load is switched off. The apparatus using low ohmic alloy is extended to the structuring of terminals, including power pins, power sockets and combinations to provide a low ohmic sensing elements in AC plugs, outlets, adaptors and extension cables with multi outlets, dissipating the heat from the sensing elements by the plugs and the larger metal heat dissipation.

The current transformer comprises at least two partial circuits (CBn) each comprising a Rogowski type winding (Cn), each of said the partial circuits being made in the form of an angular portion of a complete circuit (CB) which surrounds at least one primary conductor (10, 10A, 10B, 10C) of the transformer over 360°. The winding (Cn) of each partial circuit (CBn) is constituted by a go winding (Cn0) and by a return winding (Cn1) which extend over the angular extent (θn) of the partial circuit (CBn). For each partial circuit (CBn), the go and return windings are electrically connected in series, both having turns wound in the same direction so as to form a single winding (Cn) which presents a pair of adjacent electrical terminations (T1n, T2n) connected to an acquisition system (7, 7′).

A power consumption monitor, system, and method for monitoring power consumed by equipment, appliances, devices, buildings, and campuses is accomplished by passive sensors (12, 40) that detect power transmitted by individual conductors (C), and which include a current to voltage transformer with a passive, open-circuit electromagnetic force concentrator (22) positioned near the conductor (C). The sensor (22) generates an amplitude signal proportional to the power passing through the conductor (C). Programmable radios on a chip (32, 62, 72) and systems on a chip (34, 64, 74) are used to transmit the amplitude signal to a monitor (50) that displays the power being consumed along with actual and estimated cost and historical information. Software programs are implemented across the sensors (12, 40) and monitors (50) and a remote computer (80) to enable real-time monitoring power consumption with a resolution that spans from entire campuses down to single devices.

The size of a status indicator for monitoring a current in a power cable is reduced by integrating a bobbin for the secondary winding with a current transformer core and integrating a circuit board including output terminals with a current transformer assembly.

A differential relay for protecting a power apparatus portion of a power system, such as a bus line, includes incoming and outgoing power lines on which incoming and outgoing currents are present. The incoming and outgoing currents of each phase are applied through current transformers and then through filtering and normalizing circuits prior to application to the differential relay. The differential relay includes a circuit for determining the presence of an external fault, and maintains security by avoiding a tripping action of the relay for said external faults. Further, the relay includes circuits which in response to the external fault evolving to an internal fault alters the operation of a portion of the relay, by increasing the gain for the restraint current, enabling a directional element for supervision of the differential relay, and for extending the immediate post-fault value of restraint current, and adding a time delay for a selected period of time, all of which are used to identify an external fault evolving into an internal fault.

This invention discloses a method and a device for selecting single-phase fault of small earth current nets, which integratedly processes multiple kinds of fault signals based on the earth situation of the non-earth and arc-extinguishing coils, applies multiple kinds of line selention criteria to constitute quantification espressions showing that a line may be a fault one to get the final line selection result by integrated judgment, the selection device has good man-machine interface and is easily operated and installed, the hardware of the device is a PCI bus industrial control mainboard, and the selection algorithm is realized by virtual instrument technology to differentiate faults of single-phase earth, breakage of voltage mutual-inductors and ferromagnetic resonance and displayed by LCD.

The invention discloses a serial arc-fault circuit interrupter, comprising a power circuit, a current sensor, a current sensing circuit, an amplifying and filtering circuit, a voltage zero-crossing comparison circuit, a microcontroller, a trip trigger circuit. A current transformer collects current signals in a circuit; the current signals are converted into voltage signals through the current sensing circuit, and are input into the microcontroller through the amplifying and filtering circuit; the voltage zero-crossing comparison circuit inputs a voltage zero-crossing pulse signal into the microcontroller; the microcontroller judges arc emergence through arc characteristics analysis and is disconnected with a load circuit by the trip trigger circuit. The protection method transforms a one-dimensional time signal into a two-dimensional time signal by utilizing short-time Fourier transform, analyzes changes of fundamental component, even-order harmonic and odd harmonic component of eachcyclic wave, extracts and judges the serial arc-fault characteristics. The method has the advantages that multiple characteristics are extracted to realize comprehensive judgment of fault arc, missedtrip and balk generated in serial arc detection in small load are prevented, and the reliability of judgment is improved effectively.

The invention relates to an automatic verification system of a low-voltage current transformer in power industries. The automatic verification system comprises an input-output warehouse connection station, a grid-shaped frame type conveyor line and a feeding and blanking rotor which is connected with the input-output warehouse connection station and the grid-shaped frame type conveyor line, wherein the grid-shaped frame type conveyor line comprises a main verification conveyor line and a reserved verification conveyor line with up and down symmetrical structures, feeding and blanking station modules, appearance inspection station modules, insulation voltage-withstanding testing station modules and error verification station modules are sequentially arranged on the verification conveyor lines, middle return conveyor lines perpendicular to the verification conveyor lines are arranged between the insulation voltage-withstanding testing station modules and the error verification station modules, terminal return conveyor lines are arranged behind the error verification station modules, a conveyor line shared by the main verification conveyor line and the reserved verification conveyor line is a blanking conveyor line, and a labeling sorting station module is arranged at a part, which is close to the feeding and blanking station modules, of the blanking conveyor line; buffer areas are arranged between detection station modules on the verification conveyor lines.

Systems and methods for reclassifying instrument transformers. A line mounted device that includes a sensor that can be attached to a power line. The line mounted device generates data or representations of the power parameters of the power line. A processor in the line mounted device produces modified representations of the power parameters that are transmitted wirelessly to a microprocessor based device. The microprocessor based device also receives second representations of the power parameters from legacy instrumentation. Compensation data is produced based on the modified representations from the line mounted device and the second representations from the legacy instrumentation. The compensation data can be used to compensate or correct the representations of the power parameters from the legacy instrumentation even after the line mounted device is no longer attached to the power line.

The invention discloses online accuracy detection method and system of a current transformer. A standard current sensor is connected with a transmission line and collects a current signal on the transmission line; a current signal output by the current transformer and the current signal on the transmission line are collected by respective signal collectors and sent to a signal processor in sharingtime; and the signal processor synchronously sends the signals to a central processing system (CPU) which compares and processes the two signals received in the same clock and calculates the error conditions of the measured current transformer. The online accuracy detection system of the current transformer can be electrically connected or disconnected with a circuit of a transformer to be measured and can uninterruptedly carry out accuracy comparison measurement with the transformer to be measured under an electric operation condition for dozens of hours so as to estimate the current transformer under different operational working conditions and environmental characteristics, achieve the online accuracy estimation of the current transformer and have favorable effect.

Systems and methods for reclassifying instrument transformers. A line mounted device that includes a sensor that can be attached to a power line. The line mounted device generates data or representations of the power parameters of the power line. A processor in the line mounted device produces modified representations of the power parameters that are transmitted wirelessly to a microprocessor based device. The microprocessor based device also receives second representations of the power parameters from legacy instrumentation. Compensation data is produced based on the modified representations from the line mounted device and the second representations from the legacy instrumentation. The compensation data can be used to compensate or correct the representations of the power parameters from the legacy instrumentation even after the line mounted device is no longer attached to the power line.

The present invention discloses a method for on-line monitoring local discharge of power cable and its device. On the earthing wire of power cable a local discharge sensor is cover-connected, and a resistance divider is mounted on the voltage transformer of transformer station, and a computer can be used for making analysis and processing local discharge, and can be used for making statistial analysis. Said method can analyze maximum discharge quantity, average discharge quantity, discharge frequency, discharge phase, sewness, steepness and other discharge parameters, and can have the rich spectrogram display function, can display discharge quantity (including maximum discharge quantity and average discharge quantity) and discharge phase spectrogram, discharge frequency and discharge phase spectrogram and others. Said invention can utilize ORACLE to implement data management.

A current diagnosing device for monitoring the state of a current transformer comprises a state-detecting grounded resistor which is arranged between an output end of a secondary coil of the transformer and a signal-regulating circuit and one end of the state-detecting grounded resistor is grounded. The signal-regulating circuit connected between analog digital (AD) pins of the transformer and a central processing unit is a proportional integral circuit and is used for converting a main circuit current signal output by the current transformer into an alternating voltage signal and regulating the amplitude and phase of the signal. The central processing unit performs the AD conversion on the voltage signal output by the signal-regulating circuit. When the circuit of the current transformer is broken, the signal-regulating circuit outputs a fixed direct-current voltage signal which surpasses a set threshold value deviating from the reference voltage Vref. When the value of the counter reaches the preset period and the average values of all periods surpass the threshold value, the central processing unit gives a failure warning and instructs a tripping driving unit to drive a breaker to do disconnecting operation and the display unit displays the current and failure information of the main circuit.

The sensitivity and accuracy of a status indicator for sensing a current in an electrical circuit is improved by shifting the reference level of the transformer output to maximize the input signal to a precision voltage detector and by reducing the hysteresis of the status indicator by balancing the burden of the current transformer during the positive and negative alternations of the AC signal and by driving secondary loads with a voltage to current converter.

The invention discloses an electronic current transformer calibrating device. Two current sources respectively transmit current signals A1 and A2, wherein, the A1 is bigger than the A2 and has different frequency from the A2. A reference transformer senses the A1 and the A2 which is amplified by N folds simultaneously, and a tested transformer senses the A1. A merging unit transmits a synchronization pulse signal to the reference transformer, the tested transformer and an AD converter simultaneously, obtains digital quantities of current sampling values of the reference transformer and the tested transformer and the digital quantity of the voltage value at the two ends of a sampling resistor which is obtained by conversion with a reference AD converter at the falling edge of the synchronization pulse signal, and synthesizes the digital quantities into a data frame and sends the data frame to a control computer. The control computer compares the current signal which is obtained by sensing the A1 by the reference transformer with the current signal output by the tested transformer, calibrates the scale difference and the angular difference of the tested transformer, compares the current signal which is obtained by sensing NA2 by the reference transformer with the current signal which is obtained by converting the output voltage from the reference AD converter, and performs self calibration on the reference transformer.

A soft-load power distribution system includes a transfer switch having a first input to a utility power source with a utility alternating current (AC) voltage, a second input to a generator power source with a generator AC voltage, and an output to a load. A first switch is electrically connected between the first input and the output and a second switch is electrically connected between the second input and the output. The transfer switch has a third input, such as a go to emergency input, controlling the first and second switches. A bypass switch is electrically connected between the second input and the output. First and second sensors, such as potential transformers, sense the utility and generator AC voltages, respectively. A controller closes the bypass switch when the utility AC voltage is within a predetermined range of the generator AC voltage, and includes an output controlling the third input.

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

The invention discloses an electronic transformer amplitude and phase error checking system with a networked detection function. Specifically, the system receives analog data acquired by a standard transformer, and digital sampling value message data sent by the electronic transformer, adopts a self-adaptive algorithm based on equal interval sampling at different sampling frequencies and signal quasi-synchronous characteristics, and obtains the amplitude, phase error and other parameters of each channel by standardized calculation through comparison. The system provided by the invention can be used for amplitude and phase error checking of electronic voltage and current transformers of various types in an intelligent substation, and can realize the networked detection of single-path or multi-path electronic transformers and merge unit circuits without external synchronization signal pulse in the traditional testing scheme, so that the transformer testing system is simplified, the impact of tedious discrete functional testing work and testing blind points of a multiplexer is avoided, the testing time of equipment is shortened, and the detection efficiency of the electronic transformer is improved.

A presently-preferred embodiment of an electrical-energy meter comprises a base adapted to be mounted on a supporting surface, a current sensor assembly comprising a plurality of contact blades extending through the base and adapted to electrically contact a conductor of electrical energy, and a current transformer mechanically coupled to the base and electrically coupled to the contact blades. The electrical-energy meter further comprises a circuit board assembly comprising a main circuit board electrically coupled to the current transformer and the contact blades. The electrical-energy meter also comprises a circuit-board support member comprising a rim portion fixedly coupled to the base, and a first bracket adjoining the rim portion. The first bracket has a first and a second leg each extending away from the rim portion and the base and each being adapted to securely engage the main circuit board.

The present invention provides a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses in the range of 1000 Hz to 2000 Hz or greater. Replaceable modules include a laser chamber; a pulse power system comprised of three modules; an optical resonator comprised of a line narrowing module and an output coupler module; a wavemeter module, an electrical control module, a cooling water module and a gas control module. Important improvements have been provided in the pulse power unit to produce faster rise time and improved pulse energy control. These improvements include an increased capacity high voltage power supply with a voltage bleed-down circuit for precise voltage trimming, an improved communication module that generates a high voltage pulse from the capacitors charged by the high voltage power supply and amplifies the pulse voltage 23 times with a very fast voltage transformer having a secondary winding consisting of a single four-segment stainless steel rod. A novel design for the compression head saturable inductor greatly reduces the quantity of transformer oil required and virtually eliminates the possibility of oil leakage which in the past has posed a hazard.

The apparatus comprises: a signal modulating unit, a check meter circuit, a digital signal process unit, a display unit and a network interface unit. The analog output signals from the mutual inductor under test and the standard transformer are inputted to the signal modulating unit to make modulation; the modulated signals are inputted to the check meter circuit; the digital signals from the mutual inductor are directly inputted into the check meter circuit; the modulated analog signals and / or the un-modulated digital signals are processed by the check meter circuit to form the digital signals in clock and data synchronization; the obtained synchronous digital signals are outputted to the signal processing unit; after processed to get the amplitude, frequency and phase information of the tested signals, then figuring out the ratio difference and angle difference; comparing the index result obtained from the mutual inductor under test with the measurement result of the standard mutual inductor to evaluate the precise level of the mutual inductor under test.

Apparatus and methods are provided for electrical parameter measurements at points of interest, such as circuit breakers, machines, and the like. The devices which comprise of components that may require corrections, such as the errors induced by, but not limited to, the use of a split core mounted around a current carrier, and hence calibration coefficients are provided based on test, measurements and / or calculations respective of the devices. These coefficients may be stored in a database for retrieval when calibration of measurements received from a measuring device. In one embodiment at least one of the calibration coefficients is stored on the measuring device.

The invention relates to a system and a method for distribution network fault locating based on an improved double-terminal traveling wave method. The system comprises a terminal measurement module and a control center host computer, wherein the terminal measurement module is composed of a sensor module, a microprocessor module, a wireless communication module and a power supply module. The method comprises the following steps: a current traveling wave signal measured by a current transformer is calculated to obtain each current phase with a time scale; the phase current is decoupled, and a line mode component is selected as a traveling wave propagation mode for fault locating; an obtained traveling wave signal is uploaded to the control center host computer; the head of a travelling wave is detected, and rapid intrinsic mode decomposition is carried out on the line mode component; the arrival time of the travelling wave is determined; the wave speed is measured; and a fault is located. By adopting the system and the method of the invention, higher detection accuracy is achieved, the consistency of wave speeds of a fault traveling wave in three line sections formed by a fault point and three measuring points is ensured, and accurate online fault traveling wave speed determination is realized.

The invention discloses a device for measuring and checking errors of a digital mutual inductor, which comprises a phase self-calibration unit, a standard mutual inductor signal processing unit, a processing unit and a digital phase-locked loop unit, wherein the phase self-calibration unit is used for generating a calibration signal; the standard mutual inductor signal processing unit is used forreceiving an input signal of a standard mutual inductor or the calibration signal, and outputting a first analog signal and a first digital signal which corresponds to the analog signal and is subjected to analog / digital conversion after the processing; the processing unit receives the first digital signal and a second digital signal which is from a digital mutual inductor to be tested and synchronous with the first digital signal, and analyzes and calculates fundamental components of various signals and harmonic components in each time to obtain an angular difference, a phase difference and aphase error of the digital mutual inductor to be tested; and the digital phase-locked loop unit receives and locks the first analog signal, and receives a frequency dividing ratio data signal which is emitted by the processing unit and is based on the sampling data of the digital mutual inductor to be tested to generate a sampling frequency signal to the standard mutual inductor signal processingunit.

The data storage and processing resources required for an electric meter are reduced by basing the selection and application of phase error correction on a root mean square load current flowing through the meter.

The invention provides an electric energy meter capable of measuring residual currents. The electric energy meter comprises a shell, a wiring terminal base, a phase line, a null line, a relay, a phase line current sampling resistor, a residual current transformer and a circuit device. The relay, the phase line current sampling resistor and the residual current mutual inductor are all arranged in the shell. The phase line and the null line penetrate through the residual current mutual inductor. The circuit device comprises a voltage sampling module, a signal processing module, an A / D conversion module, an electric energy metering module, a single-chip microcomputer processing module, a relay control module, a communication module, an LCD display module, a button module and a power module. The electric energy meter can measure and record the residual currents in user lines in real time and has the functions of residual current over-limit warning and event recording. The electric energy meter only needs to be improved on the basis of an existing intelligent electric energy meter, is not high in improvement cost, does not affect the functions and the overall dimension of the existing electric energy meter and is convenient to popularize in large scale.

The invention concerns a current sensor (22; 24; 26) for substantially in real time measuring electric current in a conductor. It is suitable for application in an indicator system (1) such as a short circuit indicator system for measuring instantaneous i.e. live current value, power, reactive power, phase angle, polarity, short circuits, in single or averaged values. It comprises current responsive means comprising a current transformer (2210), adapted for mounting adjacent to said electric conductor; and sensor circuitry (2220) comprising means for emitting a non-electrical wave signal as an output; said sensor circuitry (2220) comprises current level converter circuitry (2222) comprising a current-to-frequency converter adapted to provide said non-electrical wave signal as a current level indication pulse signal (CS1) having a pulse frequency (Pfcs) which is proportional to said real time electric conductor current, when the latter is within a predetermined current interval (I1-I2). Thus, a low cost sensor is provided. The invention further relates to an indicator system (1) for an electric conductor comprising at least one of the above mentioned current sensors (22; 24; 26).

The invention relates to a device and a method for capacitor bank protection and state monitoring. The device consists of a capacitor bank, a breaker, a voltage mutual inductor, a current mutual inductor and a controller, wherein the controller controls the switching on / off of the breaker according to signals of the mutual inductors. The method comprises the following steps: calculating condensance change rate according to the condensance value of a fault phase of the capacitor bank and a rated condensance value, and taking the condensance change rate as a protection setting value; calculating the power-frequency condensance value of each phase of the capacitor bank according to the end voltage and current power-frequency effective value of each phase of the capacitor bank detected in real time; before the switching of the capacitor bank, inputting the original measured value and protection setting value of each phase in a protective device; after the switching of the capacitor bank, calculating real-time condensance change rate according to condensance monitored in real time and an original value; and finally, comparing the real-time condensance change rate and the protection setting value, and switching off the breaker when meeting the conditions so as to switch off a fault capacitor bank. The device is sensitive and reliable and is free from the influences of external factors such as capacitor imbalance, asymmetrical balance of a three-phase power supply, operating characteristic deviation between sensors and harmonic of a power system.

The invention discloses a photoelectric combined detection method aiming at a mutual inductor of a distribution network. The photoelectric combined detection method is to use various methods of a mutual inductor comprehensive detector, an ultraviolet detector, an infrared temperature measurer, a partial discharge detector, X-ray perspective detection and the like in a combined manner to meet with the requirements of judging the properties and positions of defects of the mutual inductor exactly. The photoelectric combined detection method aiming at the mutual inductor of the distribution network not only can determine whether a fault or a defect exists inside a PT (Potential Transformer) and a CT (Current Transformer) directly and judge the property of the fault or the defect in time, but also can further position the fault or the defect exactly.