7343 results about "Instrument transformer" patented technology

The current transformer comprises at least two partial circuits (CB_n) each comprising a Rogowski type winding (C_n), 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 (C_n) of each partial circuit (CB_n) is constituted by a go winding (C_n0) and by a return winding (C_n1) which extend over the angular extent (θ_n) of the partial circuit (CB_n). For each partial circuit (CB_n), 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 (C_n) which presents a pair of adjacent electrical terminations (T_1n, T_2n) connected to an acquisition system (7, 7′).

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.

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.

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.

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 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 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 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 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.

The invention discloses an optical voltage transformer which is composed of a light source, a coupler, a polarizer, a phase modulator, a polarization delay optical cable, a collimating lens, a faraday rotary mirror, an electro-optical sensing unit, a photoelectric detector and a signal processing module, wherein the electro-optical sensing unit is composed of a bismuth germinate and an A and a B electrodes which are respectively installed on an upper and a lower panels of the bismuth germinate. The invention adopts the technical proposal that an electric field leads to the change of the refractive index of the sensing bismuth germinate in the electro-optical sensing unit, the phase difference of two cross-line polarized lights passing through the bismuth germinate is changed due to the Pockels effect, and the magnitude of the electric field can be indirectly measured by measuring two coherent lights.

The invention relates to a distribution network coordination control system taking account of distributed power, comprising a main control, a simulation display screen, thirteen groups of mutual inductors, nine groups of distributed switch control terminals, two groups of distributed power installation control terminals, two groups of distributed energy-storing device control terminals, two groups of distributed power installations, two groups of three-phase inversion devices, two groups of energy-storing devices and two groups of charging/inversion devices. The invention enables the distribution system to possess a run state coordinating the distributed power in the network, thereby realizing the capability of making the clean energy utilization rate maximization in the network. By the invention, the run state of the distributed power is coordinated and optimized to realize that the load tracking rate of the clean energy reaches more than 70%, meanwhile, avoid the impact to the distribution network due to any network connection/ disaggregation of the distributed power; when the distribution network occurs an extreme accident, i.e. the distribution network occurs an isolated island running situation, the distributed power and the energy-storing devices are coordinated to run at the largest power, thereby guaranteeing that the important loads in the network are in normal power supply, and solving the power supply problem of the distribution network when the extreme accident occurs.

The invention discloses an RCD (Residual Current Device) detection device. A detection circuit in the detection device can generate a simulation drain current on the basis of a first control signal output by a controller, and the processed simulation drain current is output to the controller, a differential current transformer can output a drain current obtained in the detection to a signal processing unit which can process and output the drain current to the controller, a trip circuit can generate a simulation voltage based on a second control signal output by the controller and can output the simulation voltage to the controller and a tripping device, and the controller can determine whether the differential current transformer and/or the signal processing unit has faults or not according to the comparison results of the simulation drain current and the drain current, and determine whether the trip circuit and/or the tripping device has faults or not according to the comparison results of the attenuation ratio of the simulation voltage with a preset attenuation ratio, cue signals denoting the detection results can be output to a detection result cue unit, and the detection result cue unit can output the detection results according to the obtained cue signals. The invention further discloses an RCD detection method. By adopting the RCD detection device and the detection method provided by the invention, an RCD (Residual Current Device) can be detected in the case of the connection of a circuit breaker with a power grid.

The present invention relates to an apparatus for sensing and measuring the HV surge arrester current. It comprises two toroidal current transformers arranged coaxially with respect to the earth wire of the surge arrester, means for sensing the current signals emitted by the said transformers and for converting the said current signals in digital signals, and means for transmitting the said digital signals to an information network and analog state signals by relay activation. The two toroidal current instrument transformers are associated, respectively, one to means for sensing the normal leakage current, and the other to means for sensing the impulsive current, the latter comprising a circuit (TRIGGER) discriminating between "switching" and "lightning" signals, in which the basis for discrimination is a signal duration threshold, of about 35 mus.

The invention belongs to the technical field of all-fiber current transformers, and particularly relates to a high-precision high-reliability and all-fiber current transformer. A redundancy design method adopting active optical devices is applied so that output optical power of light source units is enabled to be more stable and stability of light source average wavelength is enhanced. A depolarization head is additionally arranged in an optical path system so that stability and measurement precision of the optical path system can be enhanced. Two beams of light are converted into electric signals to be transmitted to a signal processing unit by utilizing correlation of output light of the two output ends of a second single-mode coupler through a digital signal processing unit, and suppression of light source intensity noise is realized by utilizing a digital circuit subtraction method so that signal-to-noise ratio is enhanced and measurement precision of the system is enhanced. A low birefringence optical fiber Verdet constant and a transformation ratio error generated by change of wave plate phase delay along with temperature are enabled to be mutually compensated via an all-fiber current transformer transformation ratio temperature error automatic compensation technology so that full-temperature measurement precision of the system is enhanced.