581 results about "Three phase transformer" patented technology

To suppress the magnetizing inrush current occurring when supplying power of three phases of the transformer are performed simultaneously using three single-phase circuit breakers or a non-phase segregated operation-type circuit breaker, without providing a circuit breaker with a resistor or other equipment. A magnetizing inrush current suppression method for transformer suppresses a magnetizing inrush current occurring at the start of energizing of a three-phase transformer 300, when a three-phase power supply 100 is input to a terminal of each phase by means of a three-phase circuit breaker 200. In the method, by integrating phase voltages or line-to-line voltages on the primary side or the secondary side or the tertiary side when three-phase AC voltages are applied in a steady state to the transformer 300, steady-state magnetic flux 4, 5, 6 for each phase of the transformer is calculated, and the polarity and magnitude of the residual magnetic flux 7, 8, 9 of each phase of the transformer after the circuit breaker 200 shuts off the transformer are calculated, and the three-phase circuit breaker is caused to close simultaneously in a region 13 in which three phases overlap, each of the three phases having the polarity of the steady-state magnetic flux 4, 5, 6 equal to the polarity of the residual magnetic flux 7, 8, 9 for each phase of the transformer.

The invention discloses a power supply system for an electric locomotive. The power supply system comprises an external power supply, a traction invertor, an auxiliary invertor and a charger, wherein the charger comprises a first three-phase bridge-type inversion circuit; the alternating current side of the first three-phase bridge-type inversion circuit is connected with the low voltage side of a first three-phase transformer and the direct current side of the first three-phase bridge-type inversion circuit is connected with a storage battery; and the high voltage side of the first three-phase transformer is coupled to the output end of the auxiliary invertor. The power supply system for the electric locomotive can supply power to a traction motor by using the storage battery when a contact network fails; and low speed running of the electric locomotive can be retained.

In a three phase transformer core, amorphous metal strips are wound into rings that are combined into frames and assembled to define cores with leg cross sections that have more than 4 sides to facilitate winding transformer windings onto the legs using winding tubes. The amorphous metal layers are secured relative to one another and the core made more rigid using resin, silicon steel layers included in the amorphous metal core, or by using strapping or tying devices.

The invention discloses an electromobile charging station system with an energy storage equipment, which comprises an alternate current supply power grid, monitoring equipment, charging equipment and energy storage equipment, wherein the alternate current supply power grid is accessed into the electromobile charging station system though a high-voltage relay protection cabinet, a three-phase transformer and a low-voltage relay protection cabinet; the monitoring equipment completes monitoring and control for the electromobile charging station system and guides the operation of the whole electromobile charging station system; the energy storage equipment contains a plurality of energy storage equipment groups, and each energy storage equipment group comprises a plurality of switch controllers and energy storing devices. The electromobile charging station system can effectively alleviate impact on the power grid, which is caused by quick charging, slow power grid pressure and provide charging service for different types electromobiles manufactured by different manufacturers. The electromobile charging station system has the advantages of convenient charging service, simple and flexible operation and convenient maintenance.

The invention discloses an AC electrified railway traction in-phase power supply device based on a YNd11 connection transformer, the traction transformer of the device is a three-phase transformer (T1) connected in YNd11, and the three primary sides of the transformer (T1) in a YN connection The three phases A, B, and C are connected to the high-voltage public power grid, and the low-voltage side terminals (a, b, c) of the transformer are connected to a power flow controller (IC), and the terminals a and b are connected to the electrified railway catenary (TR) . The device can realize the same-phase power supply for the entire railway line without phase separation, and the power supply voltage is stable, ensuring the high-speed and heavy-load operation of the locomotive; at the same time, the device can eliminate the negative sequence, reactive power and harmonics of the railway traction load on the electric energy of the public grid impact, low cost, and easy implementation.

The invention discloses a multifunctional power grid simulator and a control method thereof. The main circuit of the simulator is characterized in that three mutually independent back-to-back systems are provided; the mutually independent back-to-back systems have a structure form that the input sides are three-phase PWM (Pulse-Width Modulation) rectifier, and the output sides are controllable single-phase PWM inverters for outputting voltage; mains supply is connected to the three-phase PWM inverters after the isolation of a three-phase transformer; and the single-phase PWM inverters are outputted by an LC (Inductor-Capacitor) filter. The invention as a power grid voltage generating device in a distributed power generating synchronization research can be used for simulating to output standard grid voltage and the like, and provides a grid environment as real as possible for a distributed power generating system synchronization research so as to satisfy the requirements for distributed powder generating researches.

The invention discloses a direct-current charging system of an electric automobile. The direct-current charging system comprises a three-phase transformer, a centralized type electric energy conversion unit, N direct-current conversion charging units and N charging boxes. The input end of the three-phase transformer is connected with a power grid electric wire, the output end of the three-phase transformer is connected with the input end of the centralized type electric energy conversion unit, and the output end of the centralized type electric energy conversion unit is connected with a direct-current bus. The input end of each direct-current conversion charging unit is connected with the direct-current bus. N*N switch units, N temperature sensors, N current sensors, N voltage sensors and a controller unit are further included. The output ends of the direct-current conversion charging units are connected with the input ends of the N switch units at the same time, and the output ends of the N switch units connected with the direct-current conversion charging units at the same time are connected with the input ends of N battery boxes respectively. The whole system is easy to control and low in electric energy consumption and saves more energy.

The invention provides an MMC-based multi-port hybrid power electronic transformer and a control method thereof. The power electronic transformer comprises a multi-winding transformer, a hybrid MMC converter, an LC filter, a direct-current output port and the like; the multi-winding transformer is a three-phase transformer, and comprises a primary winding and secondary windings a and b; the hybrid MMC converter is a back-to-back structure, and comprises a hybrid MMC structured AC/DC converter and a hybrid MMC structured DC/AC converter; the AC/DC converter and the DC/AC converter are connected through a direct-current side; and the direct-current side is leaded out, and can be used as a direct-current input/output port. The hybrid power electronic transformer provided by the invention comprises the traditional power transformer and the power electronic transformer, and integrates the advantages of the two; balance between the equipment effect and the cost is realized; the device comprises the direct-current port, so that access of a new energy, an energy storage unit and the like is convenient; furthermore, the device can realize reactive power compensation and dynamic voltage restorer at the same time; the electric energy quality of a power grid is further improved; individual-phase control is adopted in the control strategy aspect; and thus, the control strategy flexibility is improved.

The invention provides a dynamic voltage restorer for a three-phase four-wire distribution network, comprising a coupling unit connected in series between the power grid and the output end of the restorer, a bridge inverter connected to the coupling unit, a filter unit, the DC energy storage unit and the charging unit for charging the DC energy storage unit, the secondary sides of the three isolated single-phase transformers TA, TB, and TC of the coupling unit are respectively connected in series with the three-phase power supply grid, and the three single-phase transformers The primary sides of TA, TB, and TC are connected to the filter unit on the inverter side, and the three bidirectional thyristors are respectively connected in parallel to the secondary sides of three single-phase transformers TA, TB, and TC as electronic switches. The three contactors are used to control the switching of the three bidirectional thyristors. The input terminals of the three single-phase bridge inverters are connected in parallel to the super energy storage capacitor C1, and the super energy storage capacitor C1 is connected to the output terminal of the three-phase full-bridge rectifier circuit through the charging resistor R, and the three-phase full-bridge rectifier circuit The input terminal of is connected to the access grid terminal Us through a three-phase transformer T.

A system for transient over voltage protection of a three-phase transformer. Two surge arresters are series connected across each winding of the transformer and the center point connection of the two surge arresters is electrically connected to a middle location of the winding. Three additional surge arresters are electrically connected from each phase to ground in the case of either a delta or Y connected transformer; and/or connected from a neutral point to ground in the case of a Y connected transformer. The system allows for all of the surge arresters to be packaged as an integrated surge arrester system to minimize induced transient over voltages and high stresses on the transformer winding due to internal resonances.

The invention discloses a high-voltage high-power DC-DC conversion device comprising a cascade modular converter, a medium- and low-frequency sinusoidal three-phase transformer and an input parallel modular converter. The cascade modular converter comprises three bridge arms the same in structure. Each of the upper and lower half bridge arm of each bridge arm comprises at least two half-bridge topology power modules and a reactor, wherein the power modules and the reactor are connected in series. The input end of the medium- and low-frequency sinusoidal three-phase transformer is respectively connected to contacts of the three bridge arms. The input parallel modular converter comprises a modular converter submodule or at least two mutually parallel modular converter submodules, and the input end of every modular converter submodule is connected to the output end of the medium- and low-frequency sinusoidal three-phase transformer. The high-voltage high-power DC-DC conversion device has the advantages that the problems of voltage withstanding, voltage sharing and insufficient transmission capacity in existing high-voltage side switching devices are solved well; the high-voltage high-power DC-DC conversion device is also significant to quickening the utilization and marketization process of high-voltage DC-DC conversion devices.

A power supply device comprising an advanced harmonic current quashing (AHQ) and current pulse multiplier (CPM) (AHQ/CPM) three-phase transformer having: a primary winding placed around a magnetic core and having three primary winding input leads to connect a three phase power supply; and a plurality of secondary windings placed around the magnetic core in a predetermined winding turns configuration to generate a plurality of three phase outputs, where each three phase output of the plurality of three phase outputs has a different phase angle from all other three phase outputs, with each unique phase angle associated with a three phase output of a corresponding secondary winding being determined based on the winding turns configuration utilized for the corresponding secondary winding. A variable frequency drive (VFD) having 3N converters/inverters coupled to the secondary windings outputs exhibit substantially reduced harmonic currents and a current pulse number of greater than 6N.

The invention provides a method and a system for on-line detection of a metering abnormal state of a transformer. The method comprises the following steps of processing historical verification data ofa three-phase transformer of a high-voltage transmission line node to determine an effective value of a secondary side voltage or current; carrying out principal component analysis on the effective value to determine a principal component subspace, a residual subspace, the number of principal components and a Q statistic control threshold value of the secondary voltage or current of the three-phase transformer; computing Q statistic of an effective value of a secondary side voltage or current signal of the three-phase transformer, which is collected in real time; determining whether the three-phase transformer is in an abnormal state or not through comparison of the Q statistic with the control threshold; and finally computing a contribution rate of measured data of each phase of the transformer to the Q statistic, and judging an abnormal phase of the three-phase transformer according to the contribution rate. According to the method and the system, a gradual change metering abnormalstate under an online running condition of the transformer can be effectively detected, and the abnormal transformer can be accurately identified.

The invention discloses a modulation method of a three-phase isolation type bidirectional direct-current converter under double PWM (pulse width modulation). The modulation method includes steps of 1) determining seven switch modes by adopting a PWM strategy according to the conditions that phase shift angle and duty ratio of corresponding drive signals on two sides of a three-phase transformer change to generate different voltage and current waveforms on two sides of the transformer; 2) calculating soft switching ranges corresponding to the switch modes; 3) calculating minimum current peak flowing through the three-phase transformer within the soft switching range of each switch mode; 4) comparing calculation results to obtain the situation that the current peak flowing through the three-phase transformer is minimum on the premise of soft switching within the integral power range; 5) giving output power and voltage transmission ratio and determining the switch modes and corresponding the duty ratio and the phase shift angle by judging the range where the output power and the voltage transmission ratio belong to. On the basis of soft switching, the current peak is minimum, switch loss of switching devices is reduced and efficiency of the converter is improved.

The invention discloses a series compensation device. The device comprises at least two voltage source current converters, at least two three-phase transformers, and at least one three-phase electric reactor; the voltage source current converters are connected to a multi-loop line in series through the three-phase transformers, and the AC sides of the voltage source current converters are connected with one another through the three-phase electric reactors, thereby realizing the function of equally dividing system flow by the plurality of current converters. The device scheme provided by the application can be independently installed in a power transmission system to be used as a static synchronous series compensator, and can also be used as a component of a unified flow controller, a convertible static compensator, an inter-line flow controller and a unified power quality regulator to be connected to a power transmission system device in series. The device is capable of saving the capacity of the current converters, the application efficiency of the series compensation device is improved, and the cost and the floor area are reduced.

The invention relates to a direct current energizing method. The following steps are adopted: in a traditional direct current power supply system composed of a three-phase alternating current synchronous generator, and/or a three-phase transformer, and a three-phase rectifier, a alternating current synchronous generator of more than three phases and a rectifier which is matched with the alternating current synchronous generator in terms of a same phase number are adopted to carry out replacement and combine into an energy saving type direct current system. Through the adoption of the method of the invention, a line voltage loss of 15.8% at most in an existing three-phase power system can be reduced and even eliminated in theory, so that as for the apparatus adopting the method, the direct current voltage of the apparatus is higher than the direct current voltage of a traditional set of three-phase alternating current power generating added with the rectifier. According to the direct current energizing method, the system output power has a gain of a same degree, and the direct current power output by the rectifier is at least 10% higher than the direct current power output by the traditional rectifier. An electrical loss reduction value of the synchronous generator or the transformer is no less than 5%; therefore, the set is advantageous by being highly efficient and energy saving. An added cost proportion of the set is less than power and efficiency growing rate, and substantial technical progress and good economic benefits are achieved.

The invention discloses a comprehensive control system based on high voltage motor control and reactive power compensation. The system comprises a three-phase transformer, power units, a voltage transformer, an isolating transformer, a current transformer and a master control unit, wherein each power unit comprises a power unit controller. Correspondingly, the invention also discloses a comprehensive control method based on the high voltage motor control and the reactive power compensation. By the comprehensive control system and the comprehensive control method based on the high voltage motor control and the reactive power compensation, both the high voltage motor control and the reactive power compensation can be performed, thereby greatly bettering energy saving effects, reducing system cost and fulfilling an optimal energy saving aim.

The invention discloses a symmetry control type three-phase three-level direct current converter and a symmetry control method thereof, belonging to the field of power electronic converters. The converter comprises a power circuit (1), a half-bridge three-level circuit (2), a full-bridge circuit (3), a three-phase isolation transformer (4) and a rectifier filter circuit (5) which are connected insequence. The converter is characterized in that all switching tubes in the converter have the same conduction time; the adjacent switching tubes are conducted in turn; and the turn-on time interval is 1/6 switching cycle. The converter has the following technical effects: the voltage stress of all the switching tubes in the converter is half the input voltage; the three-phase transformer and thesymmetry control mode improve the input and output current ripple frequency, thus reducing the volume of the input and output filters; and meanwhile, the current stress of the switching tubes is effectively reduced.