34results about How to "Compensation for reactive power" patented technology

A method of reactive power regulation in an electrical network in which electrical power is produced by an electrical generator preferably driven by the rotor of a wind power installation and suitably modulated by means of a compensation device between the generator and the network for the compensation of reactive power, and an apparatus for producing electrical energy in an electrical network, preferably an electrical generator driven by the rotor of a wind power installation and a compensation device between the generator and the network for the compensation of reactive power. The compensation device is so regulated that the electrical power delivered to the consumer has a reactive power component which is adapted in respect of its phase, amplitude and/or frequency to the consumer in such a way as to compensate for the reactive power in the consumer.

The railway system has a DC voltage catenary (20) connected to a rectifier bridge block (40) that is in turn connected to a transformer (30) joined to a three-phase AC grid (10). The device (50) has a first DC/DC voltage raising block (51) connected between the catenary (20) and an intermediate bus that is connected to a second DC/AC three-phase current generation block (52) joined to the transformer (30). The first block (51) allows raising the DC voltage of the catenary (20) generating a controlled voltage with which the second block (52) generates a high-quality three-phase current that is delivered to the grid (10).

The invention discloses a photovoltaic energy storage hybrid system and a control method thereof. The photovoltaic energy storage hybrid system includes a photovoltaic power generation device, an energy storage device, a DC bus, a first DC/DC converter, a first controller for controlling the output of the first DC/DC converter, a second DC/DC converter arranged between the energy storage device and the DC bus, a second controller for controlling the second DC/DC converter in order to stabilize a DC bus voltage, a DC/AC converter arranged between the DC bus and the tail end of a distribution network, and a third controller for controlling the DC/AC converter. The second controller, by detecting the voltage applied to the DC bus and comparing the same with a preset reference voltage, controls the second DC/DC converter according to a comparison result so as to charge or discharge the energy storage device, and then restores the DC bus voltage to the reference voltage so as to stabilize the voltage at the tail end of the distribution network and greatly improve the power quality of users at the tail end of the distribution network.

The invention provides a novel rotating rectifier with a fault monitoring function, and relates to rotating rectifying systems. The invention aims at solving the problems that an existing rectifier is low in output power of an alternating-current exciter and high in harmonic component, a rotating rectifying controller cannot be timely started and a system fault exists. The novel rotating rectifier with the fault monitoring function comprises a three-phase triple voltage rectifying circuit, an alternating-current exciter, a rotating bridge rectifier module based on VIENNA, a start power module, a start resistor, a rotating rectifying controller, a synchronous electric exciter set, a fault detection module, a wireless communication device, a first wireless transceiving device, a second wireless transceiving device and an external monitoring module. According to the novel rotating rectifier with the fault monitoring function, a neutral-point potential balance method of injecting zero-sequence voltages is adopted, zero-sequence voltages VZ(+) and VZ(-) are injected into a three-phase reference voltage at different moments, and the problem is solved that two capacitor voltages of a direct current busbar are not balanced.

The invention discloses a balancing power distribution system for 0kV and below power distribution network, belonging to the electrical distribution technology field. A first, second and third AC output ends (U) (V) (W) of a synthetic compensating gear (101) are respectively connected in parallel with a first, second and third feeder lines (111) (112) (113) of a switch-in electric network, the synthetic compensating gear is controlled as a current source and output the current signal, the current signal is superposed to the load current of a three-phase non-linearity asymmetric load, a three-phase symmetrical electric network current is obtained at the three-phase power distribution network side. A first, second and third public joint points of the synthetic compensating gear is located at the high-voltage side of a step-down distributing transformator or at the low-voltage side of the step-down distributing transformator. The balancing power distribution system can meet various electrical distribution requirements of a low-voltage power consumer, and realize the quick balancing of the power distribution network three-phase power, at the same time, the balancing power distribution system can compensate the electric network reactive power, restrain the system harmonic and effectively improve the utilization ratio of the distributing transformator.

The invention discloses a direct hanging type large-capacity electric energy quality comprehensive managing device for an electrified railway. The direct hanging type large-capacity electric energy quality comprehensive managing device comprises an active compensation system and a passive compensation system. The passive compensation system comprises two passive high-pass filters for filtering higher harmonics out and providing partial capacitive reactive power, and the active compensation system is formed by connecting a plurality of active compensation units in parallel. The direct hanging type large-capacity electric energy quality comprehensive managing device has the advantages of being simple in structure, low in cost, good in reliability, capable of solving various electric energy quality problems and the like.

The present disclosure relates to a reactive power compensation system including a reactive power compensation unit for measuring compensate reactive power, an impedance measurement unit for measuring an impedance value of each of a plurality of loads, and a learning control unit for controlling the reactive power compensation unit based on the measured impedance value.

The invention discloses a unified power quality regulator for medium-voltage distribution networks. The unified power quality regulator comprises three single-phase energy storage conversion units, three single-phase multi-winding parallel transformers and three single-phase series transformers which correspond to the A, B and C phases. Each single-phase energy storage conversion unit includes 2*nfirst units and n second units. Each first unit includes a single-phase full-bridge AC-DC converter, a power supply side bidirectional DC-DC converter, an energy storage device and a load side bidirectional DC-DC converter. Each second unit includes a three-phase six-arm DC-AC converter. The unified power quality regulator is mainly used in medium-voltage distribution networks at an intermediate(10kV or 35kV) voltage level, and can restrain the harmonic current on the load side, balance the currents of the three phases of a distribution transformer, improve the utilization ratio of transformers, dynamically compensate the reactive power of the load, improve the power factor of a distribution network, rapidly compensate the active power of the load, and improve the stability and reliability of the voltage of power supply to users.

The invention discloses a unified controller and control method of a single-stage Z-source photovoltaic grid-connected inverter. A single-stage photovoltaic grid-connected system based on a Z-source inverter utilizes a Z-source network and inverter direct connection time to realize boosting; furthermore, grid-connected current inversion control can be realized; the unified controller is integrated with harmonic and reactive compensation, and is compact in overall structure, relatively high in efficiency and relatively reliable in operation.

The invention relates to a method and an electrical converter of an elevator. In the method a controller of the electrical converter determines a first reactive power produced by a smoothing filter using pre-determined information on impedance of the smoothing filter. The controller may also receive information on a second reactive power from a remote node over a communication channel, the second reactive power being produced to a grid. The controller adds the first reactive power and the second reactive power to yield a total reactive power. The controller requests the electrical converter to make a plurality of compensative connections in the converter matrix to compensate the first reactive power or the total reactive power.

The invention discloses a low-voltage three-phase imbalance automatic regulating device. The automatic regulating device comprises a low-voltage distribution system, a detection unit, a reactive compensation controller, a switching unit and an active filter device, wherein the low-voltage distribution system is used for transferring a three-phase voltage signal and a three-phase current signal to the detection unit; the detection unit is used for transferring signals detected by a load to the active filter device, and the active filter device is used for processing three-phase imbalance harmonic signals in a power grid and compensating a harmonic current; the detection unit is used for transferring signals detected at a system side to the reactive compensation controller, and the reactive compensation controller is used for carrying out comparison operation and outputting the signals to the switching unit; and the switching unit is used for regulating the voltage and current of the low-voltage distribution system. The low-voltage three-phase imbalance automatic regulating device disclosed by the invention is specially designed for electric power departments and power consumers, the reactive power can be effectively compensated, harmonic waves can be treated, the quality of electric energy can be improved, and the loss can be reduced; and the low-voltage three-phase imbalance automatic regulating device is necessary energy-saving equipment.

The invention relates to a magnetic control transformer technology, in particular to a split core type magnetic control intelligent transformer and a control method, a transformer iron core comprisesthree phases of iron core columns, an upper yoke and a lower yoke, each phase of iron core column is divided into a first half iron core and a second half iron core, and the length is L; each half iron core is provided with a section of small iron core with the length of lt, the section shape being the same as that of the half iron core and the section area being half of the section area of the half iron core; lt is less than L; a transformer winding structure comprises a secondary side winding with a half number of turns wound on each half iron core, a primary side winding surrounds the secondary side winding and wraps the first half iron core and the second half iron core, and an insulation distance is reserved between the primary side winding and the secondary side winding. According tothe transformer, the excitation reactance of the transformer is adjusted through direct-current excitation, voltage control without an on-load voltage regulating switch can be achieved while the buck-boost function of a traditional transformer is achieved, and reactive power can be dynamically and smoothly adjusted and voltage can be stabilized in cooperation with a fixed capacitor bank.

The invention provides an SVG (Scalable Vector Graphics) based over-frequency/ under-frequency anti-islanding device of a distributive photovoltaic generating system. The device comprises a cabinet body, a scram button, a voltmeter, an operating switch and a static var generator; the scram button is mounted on the surface of the cabinet body; the voltmeter, the operating switch and the static var generator are mounted in the cabinet body; the operating switch is chained with the static var generator through a cable; the voltmeter is connected to a cable between the operating switch and the static var generator through a conductor. According to the device, the static var generator can be adaptively added to a distribution and transformation medium- and low-voltage bus by a distributive photovoltaic way, and a 380V distribution branch box, a 220V/ 380V consumer distribution box and other typical forms can be introduced; the introduced static var generator does not damage a distributive photovoltaic generating system device, electrical load, low-voltage fuse and the like; the input capacity of the static var generator is connected with the capacity for forming an island system.

The invention relates to a power quality regulating service system, which comprises a monitoring server and a regulating service module connected to a power grid through an electric reactor in parallel, wherein the regulating service module is connected with a wireless data transmission module and communicates with the monitoring server through the wireless data transmission module; the regulatingservice module comprises a three-phase detection module, a reactive power detection module, a harmonic detection module and a voltage detection module; if three-phase imbalance of the power grid is detected, the cause of the three-phase imbalance is determined; the reactive power detection module is used for judging whether the power grid is in an inductive state or capacitive state; the harmonicdetection module is used for detecting the direction of harmonic current in the power grid; and the voltage detection module is used for detecting whether voltage is subjected to single-phase or three-phase sudden swell and drop within a rated range or not in real time. According to the power quality regulating service system, the defects of traditional capacitor compensation can be avoided, therequirements of power quality and energy-saving application of the power grid are met, the power quality is greatly improved and the line loss of a low-voltage distribution network can be greatly reduced.

The invention relates to an active power filter command current extraction method with a power factor being adjustable. The method comprises the following steps: acquiring a voltage of a three-phase system, and performing phase-locking calculation to obtain a phase of the system; acquiring current of the three-phase system, and performing CLARK-PARK transformation on three-phase current by the system phase to obtain a d-axis component and a q-axis component; processing the d-axis component and the q-axis component through a low-pass filter to obtain a fundamental wave active component and a fundamental wave reactive component; determining a d-axis component and a q-axis component needing to be reserved by a network side system; and performing CLARK-PARK reverse transformation on the reserved d-axis component and the reserved q-axis component, and subtracting system current from a component obtained through the reverse transformation to obtain command current. Through adoption of the method, harmonic current and reactive power of a specified capacity are compensated at the same time by an active power filter, and the compensation performance and utilization ratio of the system are improved.

The invention discloses a broadband filtering compensation transformer, wherein each of three phases of the transformer adopts two layers of foil windings which are insulated from each other, the two layers of foil windings which are insulated from each other are also two polar plates of a capacitor, voltage difference is generated between the two windings through a wiring mode, and a broadband inductance and capacitance (LC) filtering absorption circuit is formed. The broadband filtering compensation transformer is reasonable in design, the broadband LC filtering absorption circuit is formed, the higher harmonic of a power grid is effectively eliminated, and the reactive power of a network is compensated.