233 results about "Compensation winding" patented technology

Current testing/measuring apparatus 10 comprises a flexible member 12 having a first end 14 and a second end 16. In use, the flexible member 12 is arranged to locate around a conductor 11 carrying a current to be measured. In particular, the current measuring apparatus 10 comprises a Rogowski coil. The ends of the flexible member 12 are coupled together in use but a gap is created between the ends. This distance can generate errors in the current measurement and the present invention provides compensation means 28 in the form of a compensation windings. The compensation windings comprise a planar spiral conductor provided on a printed circuit board to compensate for the separation distance between the first end and the second end.

transformer includes a soft magnetic core on which a primary winding arrangement, a secondary winding arrangement, and a compensation winding arrangement are arranged. The compensation winding arrangement is connected to a current control device which feeds a compensation current into the compensation winding arrangement using a control signal. A magnetic field measuring device measures the magnetic field in the core of the transformer or the stray magnetic field that closes outside the core via an air path and provides the control signal.

The invention relates to a standard calibrating device of a high-voltage three-phase combined mutual inductor, which belongs to an electronic calibrating device used for the electric energy measurement and the current measurement. The electronic calibrating device comprises a single chip, an A/D converter, a front end circuit and a 380v three-phase power supply; three current risers and the three-phase power supply adopt the star connection and are connected with a compensation winding Ns of a compensation adjusting coil in parallel, a secondary winding of the compensation adjusting coil is connected with a primary winding of a standard current mutual inductor; three voltage risers and the three-phase power supply adopt the delta connection and are connected with a compensation winding Y of the compensation adjusting coil in parallel, the secondary winding of the compensation adjusting coil is connected with a primary winding of a standard voltage mutual inductor, and the secondary windings of the standard circuit mutual inductor and the standard voltage mutual inductor are all used for connecting the tested three-phase combined mutual inductor. The invention can simulate the actual operation status of the mutual inductor, carry out the calibration test under the actual operation status and correctly reflect the actual error and the relevant performance of the three-phase mutual inductor.

The present invention relates to a transformer being protected against direct current induced by geomagnetic flux changes, so called zero sequence current, whereby it comprises at least one compensation winding for direct current on the transformer core to compensate for undesired magnetization, by adding a current opposite to the direction of the magnetization caused by the zero sequence current carried by the alternating current to be transformed to reduce high magnetization saturation levels.

The invention discloses a fiscal electricity meter for measuring energy supplied to a load. The load current flows through the primary coil of a sensor and induces an EMF (Electromotive Force) that can represent the current flowing in the secondary coil. The secondary coil includes a sensing winding arranged to couple more strongly to the primary coil and a canceling compensation winding having the same and opposite multi-turn conductor areas so as to provide an inactive response to an external magnetic field. The windings are arranged so that their magnetic axes are coaxial and aligned so that they also provide ineffective response to external magnetic fields with field gradients.

The invention discloses an autotransformer with low-voltage compensation, comprising a main transformer, a voltage regulator and a compensating device, wherein the main transformer comprises a low voltage winding, a common winding and a series winding; the voltage regulator comprises a voltage regulating switch, a voltage regulating winding and a first exciting winding which carries out excitationfor the voltage regulating winding; the compensating device comprises a compensation winding and a second excitation winding which carries out excitation for the compensation winding; the beginning end of the low voltage winding is connected with the beginning end of the first exciting winding; and the tail end of the low voltage winding is connected with the compensation winding in series. The autotransformer is characterized in that the tail end of the first exciting winding is connected with the tail end of the compensation winding. By adopting the voltage regulating compensation connection method of the invention, the low-voltage compensation is complete compensation for the autotransformer of variable flux voltage regulation of a neutral point, so that low voltage fluctuation can bethoroughly solved when a transformer regulates the voltage.

The invention discloses an automatic direct-current magnetic bias compensation device of a metering winding of a current transformer. The automatic direct-current magnetic bias compensation device is characterized in that a metering iron core of the current transformer is provided with the metering winding and a compensation winding which are independent of each other, and the compensation winding is connected with the automatic direct-current magnetic bias compensation device. The automatic direct-current magnetic bias compensation device is used for detecting the size and phase position of an even harmonic component in an output signal of the secondary-side metering winding of the current transformer, and therefore a direct-current source is controlled to inject reverse direct current of the corresponding amount to the secondary-side compensation winding of the current transformer as compensation current, the compensation current generates a magnetic field in the compensation winding, a magnetic field generated by the primary-side direct current is offset, and then automatic and on-line compensation for the direct-current magnetic bias of the current transformer is achieved. The automatic direct-current magnetic bias compensation device is remarkable in effect of automatically compensating for the direct-current magnetic bias of the current transformer.

The invention relates to an electric current measurement technology, in particular to an electric current transducer suitable for measuring an output current of an automobile alternating-current generator in a mutual inductance mode, a double-storage-battery automobile power supply system including the electric current transducer, and a hybrid electric automobile adopting the double-storage-battery automobile power supply system. The electric current transducer used for an automobile and based on zero magnetic flux compensation comprises a magnetic core wound by an output wire of the automobile alternating-current generator, a secondary winding wound on the magnetic core, a detection winding wound on the magnetic core and a magnetic flux compensation device coupled between the secondary winding and the detection winding, wherein the magnetic flux compensation device supplies compensating current for the secondary winding according to potential difference between two ends of the detection winding, and the potential difference is enabled to tend to zero. According to the electric current transducer used for the automobile and based on the zero magnetic flux compensation, due to the fact that an auxiliary magnetic core and a compensating winding are saved, microminiaturization of the transducer is facilitated.

The D.C. current-sensing equipment incldues sensing head, power supply transformer, excitation transformer, resistor, inductor, diode, operation amplifier and driver, and its sensing head structure is characterized by that it has first ring detection iron core and second ring detection irno core, every iron core is equipped with first detecting winding and second detection winding which are identical in number of turns, after they are assembled, its exterior is equipped with compensation winding, its whole body is placed in shielding iron core hollow cavity, the exterior of the shielding ironcore is equipped with secondary winding. Said invention has the advantages of open-loop measurement and closed-loop measurement.

A device for reducing a magnetic unidirectional flux fraction in the core of a transformer is provided. The device has a measuring device that provides a sensor signal corresponding to the magnetic unidirectional flux fraction, a compensation winding that is magnetically coupled to the core of the transformer, a switching unit arranged electrically in a current path in series with the compensation winding in order to feed a current into the compensation winding. The action of the current is directed opposite to the unidirectional flux fraction. The switching unit can be controlled by a regulating variable provided by a control device and can be switched into a conductive state during a predefined time interval and in accordance with the regulating variable, the switch-on time being mains-synchronous. A device for limiting the current in the current path is provided and the sensor signal is fed to the control device.

A method and device for testing the current proportion standard type high-correctness current transformer features that a microprocessor is used to analyze the data about zero test signal of test winding to generate automatic compensation signal of zero magnetic-flux, or a inverter is used to process the difference signal to obtain the compensation signal. Its advantages are no need of manual switching-over and no interference from frequency of power supply.

A power transformer with the one-way flux compensation function is characterized in that the transformer (20) is provided with a soft magnetic core (4), the soft magnetic core (4) is provided with a primary winding device (1), a secondary winding device (2) and a compensation winding device (3), the compensation winding device (3) is connected with current control devices (12 and 13), the current control devices feed compensation currents (16 and 17) into the compensation winding device (3) according to control signals (14 and 15), and the compensation currents (16 and 17) are used for offsetting one-way flux (5) in the magnetic core (4). The control signals are provided by a magnetic field measuring device (30) according to measurement on flux related to currents in the primary winding device or the secondary winding device.

The invention relates to the field of power system reactive power compensation, in particular to a 750 kV magnetic-control type controllable paralleling reactor excitation system and an achieving method of the 750 kV magnetic-control type controllable paralleling reactor excitation system. Energy is obtained by a magnetic-control type controllable paralleling reactor compensation winding bus through self-excitation type rectifying units in an excitation system, excitation current is supplied to a control winding of a magnetic-control type controllable paralleling reactor. Two groups of self-excitation type rectifying units form a main preparing pair, online redundancy is carried out, and switchover can be achieved by means of triggering and pulse blocking. Pre-excitation in the process of load closing of an electric transmission line can be achieved by means of energy obtaining of a station used variable side bus through an external excitation type rectifying unit in the excitation system, overvoltage of the load closing is restrained, and the groups of the rectifying units are in a stand-by condition in the normal operation of the magnetic-control type controllable paralleling reactor. The 750 kV magnetic-control type controllable paralleling reactor excitation system and the achieving method of the 750 kV magnetic-control type controllable paralleling reactor excitation system solves the contradiction between the limitation of overvoltage of the 750 kV electric transmission line and reactive compensation. The magnetic saturation level of an iron core of the magnetic-control type controllable paralleling reactor is changed due to the fact that the excitation system is controlled by the thyristor, and smooth adjustment of the capacity of the magnetic-control type controllable paralleling reactor can be achieved.

The invention provides a superimposed large-current bias alternative-current (AC) current measuring device, which aims at measuring small AC current which is superimposed on large-current bias, is wide in measurement frequency range and capable of accurately measuring a small AC signal under the situation of the large-current bias. The measuring device comprises a current transformer and a direct-current (DC) current measuring device, wherein a closed magnetic core of the current transformer is respectively wound with secondary sensing windings with turns of N2 and DC compensation windings with turns of N1, and the measured current is used as primary current of the transformer to run through the center of the magnetic core; and the DC compensation windings are connected with a DC current measuring device through a DC current drive circuit and a low-pass filter circuit, which are sequentially connected with each other, the DC current measuring device converts the measured current signal to an electric signal, after the AC component is filtered by the low-pass filter circuit, one DC current which can counteract the magnetic sensing strength produced by the DC bias current in the current transformer is outputted through the DC current drive circuit.

The invention provides a broadband current transformer. The broadband current transformer comprises a detection iron core (1), wherein a detection winding (2), a detection winding copper screen (3), an inner magnetic screen (4), an inner compensation winding (5), an outer magnetic screen (6), an outer compensation winding (7), an outer compensation winding copper screen (8), a secondary winding (9), a secondary winding copper screen (10) and a primary winding (11) are arranged outside the detection iron core (1) from an inner layer to an outer layer in sequence; compensation capacitors (13) are connected at two ends of the outer compensation winding (7) in parallel, and compensation capacitors (14) are connected at two ends of the secondary winding (9) in parallel; and the number of windings of the inner compensation winding (5) is equal to that of the outer compensation winding (7). According to the broadband current transformer, main error sources of the current transformer are eliminated, the capacitive error of the broadband current transformer is reduced, and the measurement accuracy of high-frequency current is improved.

The invention provides a high-accuracy current comparator and a self-checking method and belongs to the field of alternating current precision measurement. The high-accuracy current comparator comprises an iron core, a primary winding W11, a primary compensation grounding winding W12, a secondary winding W21, a secondary compensation winding W22 and a detection winding WD, wherein the primary winding W11, the primary compensation grounding winding W12, the secondary winding W21, the secondary compensation winding W22 and the detection winding WD are wound on the iron core. The primary winding has three groups of input terminals. The number of turns of the primary winding connected with the three groups of input terminals increases tenfold. The secondary winding is divided into M sections of sub-windings, wherein each section of sub-winding is provided with two taps and the number of turns of each section of sub-winding is the same with that of the primary winding La3-Lb. Each section of sub-winding of the secondary winding is connected in series through the tap. Two taps connected in series of the adjacent two sections of sub-windings form an end. All ends of the secondary winding is numbered sequentially from the first section, the number being from 0 to M. The number of sections of the secondary winding connected in the secondary winding input terminals is changed through a band switch.

The invention provides a method for compensating heterogeneity of a shield magnetic field coil through a winding. The shield magnetic field coil is wound by the compensating winding with the particular specification, and distribution of magnetic lines of force of an original magnetic field coil is changed through the compensating winding, so that the heterogeneity of the shield magnetic field coil is increased in a magnitude mode. The magnetic field generated by the compensating winding has equal magnetic force and the opposite direction with the heterogeneous field additionally produced because a magnetic shield layer changes distribution of the magnetic lines of force in the magnetic field coil, and therefore the purpose of compensating the heterogeneity of the shield magnetic field is achieved.

The invention provides a PCB and a circuit board. The PCB comprises a via hole, and a compensation winding wire and a routing wire which are connected with the via hole, wherein the at least one via hole of the PCB is provided with the compensation winding wire surrounding the via hole; the compensation winding wire has no adjacent reference layer; and one end of the routing wire is connected to any position on the compensation winding wire. Through the technical scheme of the PCB and the circuit board, the impedance mismatching problem of the via hole of the PCB can be solved, and thus the signal quality is improved.

The invention provides a compensating winding system of a power transformer with a single-phase four-column iron core structure. The compensating winding system comprises a left compensating winding and a right compensating winding wound on a left side column and a right side column, and a left compensating winding and a right compensating winding wound on an iron yoke, wherein the outlet end of the left compensating winding wound on the left side column is connected with the outlet end of the left compensating winding wound on the iron yoke, and the outlet end of the right compensating winding wound on the right side column is connected with the outlet end of the right compensating winding wound on the iron yoke. With the adoption of the compensating winding system, according to the Faraday law of electromagnetic induction, a main magnetic flux generated by windings, an additional magnetic flux generated by window-penetrating current and an induction magnetic flux generated by compensating windings can be generated in the iron core, the directions of the induction magnetic flux and the additional magnetic flux are always opposite, and the aim of inhibiting the additional magnetic flux generated by the window-penetrating current is effectively fulfilled.

The invention discloses an electrified railway in-phase power supply comprehensive compensation device and a comprehensive compensation method thereof, and relates to the technical field of electrified railway in-phase power supply. One of the topological structures is as follows: compensation windings ab and dc of a traction-compensation transformer with the primary side connected with three phases of a three-phase high-voltage bus HB; a reactive compensation unit SVG1 is connected to an ac port of the compensation winding, and the reactive compensation unit SVG2 is connected with an ad portof the compensation winding; a second one of the topological structures is as follows: compensation windings ab and dc of the traction-compensation transformer with the primary side connected with three phases of the three-phase high-voltage bus HB; the reactive compensation unit SVG1 is connected to the ac port of the compensation winding, the reactive compensation unit SVG2 is connected to the ad port of the compensation winding, and a reactive compensation unit SVG3 is connected with an ab port of the compensation winding; and the input end of a controller CD in the measurement and controlsystem MCS is respectively connected with the measurement signal output ends of a voltage transformer VT and a current transformer CT.

Disclosed is a pole-change type motor that provides a variable-speed (two-pole or four-pole type) operation system capable of reducing the load of the motor of the normal operation system and improving the cooling efficiency. In case of a quick operation, the motor switches over to the two-pole type according to the control of a relay section. At this time, the load of the motor is reduced by offsetting an abnormal magnetic field distribution formed due to the same polarity of adjacent main windings using compensation windings of an opposite polarity. If the quick operation is needed, the motor switches over to the two-pole type, and operates at a high speed to achieve the quick cooling. Then, if a standard operation is possible with the lapse of the predetermined time, the motor switches over to the four-pole type, and operates at a low speed to achieve an effective cooling.