35results about How to "Compensation for reactive power" patented technology

A modularized active power filter includes a control module and at least one power module. The control module automatically identifies the number of parallel connected power modules and generates one set of PWM signals to correspondingly control the parallel connected power modules, so as to provide a final compensation current by a single power module or by plural power modules. Thereby, the compensation demand of a load is met. Consequently, the modularized active power filter is able to improve flexibility of compensation capacity, to shorten the time for service, to be suitable for mass production, and to lower the manufacturing cost.

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 invention discloses a method for adjusting power grid voltage. The method includes the following steps that: a voltage control mode or and reactive power compensation mode are alternatively adopted according to the range of power grid voltage actual values, and the output reactive power reference value of a static var generator is obtained; the output reactive power current reference value of the static var generator is obtained according to the output reactive power reference value; and the output reactive power current actual value of the static var generator is obtained, and the output reactive power current of the static var generator is adjusted according to the output reactive power current actual value and the output reactive power reference value, and therefore, adjustment of the power grid voltage can be realized. With the method adopted, reactive power compensation and power grid voltage adjustment can be realized at the same time, and rapid and reliable adjustment of the power grid voltage can be realized.

The invention relates to an ice melting system for an overhead contact system of an electric railway. A first synchronous reactive generator and a second synchronous reactive generator are respectively arranged on adjacent power supply arms of two electric power substations of the overhead contact system, wherein the first synchronous reactive generator is used for generating inductive reactive power during ice melting and transmitting the inductive reactive power to the overhead contact system; the second synchronous reactive generator is used for generating capacitive reactive power equivalent to the inductive reactive power during ice melting and transmitting the capacitive reactive power to the overhead contact system; and the second synchronous reactive generator is connected with the power supply arm of one electric power substation through a switch (203) and is also connected with the power supply arm of the other electric power substation through a second switch (202). According to the ice melting system disclosed by the invention, reactive current flows from the power supply arms to generate joule heat energy for melting ice. The influence on a last-stage traction power supply system by the reactive power generated by the ice melting system disclosed by the invention is avoided; when the ice melting is not required, the power of two synchronous reactive generators is supplied by respective electric power substations, and thus real-time compensation of reactive power is realized and the aim of increasing the power rate of a traction network is achieved.

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 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 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 invention discloses a unified power quality regulator used in a medium-voltage distribution network. The invention includes three single-phase energy storage type conversion units corresponding to each phase of the ABC three-phases, and three single-phase multi-windings connected in parallel. type transformer and three single-phase series-connected transformers. The single-phase energy storage type conversion unit includes 2n first units and n second units. The first unit includes a single-phase full-bridge AC-DC converter and a bidirectional DC-DC converter on the power supply side. A DC converter, an energy storage device, and a load-side bidirectional DC-DC converter, and the second unit includes a three-phase six-leg DC-AC converter. The invention is mainly used in medium-voltage distribution networks with medium-level (10kV or 35kV) voltage levels. It can suppress the harmonic current on the load side, balance the three-phase current of the distribution transformer, improve the utilization rate of the transformer, dynamically compensate the reactive power of the load, and improve the distribution efficiency. The network power factor can be quickly compensated for the active power of the load, and the stability and reliability of the user's power supply voltage can be improved.

The invention discloses a comprehensive optimization system for power quality of a distribution network, comprising: a monitoring server, an optimization device, and a wireless data transmission module; the optimization device includes: a three-phase detection module, a reactive power detection module, a harmonic detection module, and a voltage detection module; The monitoring server includes: a three-phase regulation module, a reactive power compensation module, a harmonic filter module, and a voltage regulation module. It can solve the defects of traditional capacitor compensation, meet the power quality and energy-saving application requirements of the distribution network, and greatly improve the power quality; modular design, each module can compensate reactive power, harmonics, and three-phase unbalance independently or simultaneously; no capacity attenuation, long lasting.