Novel static var compensator based on single-stage conversion module cascade converter

Abstract

The invention provides a novel static var compensator based on a single-stage conversion module cascade converter. The novel static var compensator based on a single-stage conversion module cascade converter includes multiple single-phase and three-phase main power circuits which are formed through cascade connection of a plurality of module units, and a plurality of branches which are formed through serial connection of inductors and capacitors and are in parallel connection with the main power circuits. The novel static var compensator based on a single-stage conversion module cascade converter has the advantages of being high in the SVG dynamic response speed, being low in the harmonic wave content, being low in power dissipation of the device, being small in volume, being light in weight, being simple in SVC control, and being low in price. The novel static var compensator is formed on the basis of a controllable rectifier circuit transmitting the energy in single direction; the branches which are formed through serial connection of inductors and capacitors and are in parallel connection with the controllable rectifier; the branches can provide advanced fundamental wave reactive power and can also filter the low-order harmonics so as to achieve the aim of providing continuously adjustable reactive power for the system by controlling the input current of the controllable rectifier and restrain or eliminate the power grid current harmonics.

Description

technical field [0001] The invention relates to a novel construction method of a static var compensator in an electric power system, and belongs to the technical field of dynamic var compensation control in power quality control technology. Background technique [0002] With the increasingly widespread application of power electronic devices and the large number of non-linear loads connected to the power system, the problem of power quality in power supply has become increasingly prominent. Therefore, in recent years, power quality control technology centered on power electronic converters has attracted more and more Much attention. The research on harmonic suppression devices and reactive power compensation devices used in power systems has become one of the most important research fields in the field of electrical engineering. The recognized role of these power quality control devices is to improve the power factor of power supply systems and loads , reduce equipment capa...

AI Technical Summary

Problems solved by technology

Among them, the static var compensator (SVC) is usually composed of a thyristor-controlled reactor (TCR) plus a fixed capacitor (FC) (the capacitor is usually connected in series with the inductor and used as a low-frequency harmonic filter), and its advantages are: continuous compensation can be realized , can be adjusted in phases, reliable in operation, simple in control, and cheap in price; its main disadvantage is that it will generate a large number of harmonics, and a filtering device must be added during use, and the reactor is bulky and heavy

Compared with the static var compensator (SVC), the static var generator (SVG) is composed of fully controlled modern power electronic devices, using modern power electronic technology, while realizing continuous dynamic reactive power compensation, it can also control the power grid It has a series of advantages such as faster dynamic response speed, stronger voltage flicker suppression ability, less harmonic content, low power consumption of the device, small size, light weight (no need for bulky and heavy reactors), etc. , its main disadvantages are: expensive, complicated control

From the above, it can be seen that the two typical shunt compensation devices that are commonly used in the past and can continuously and dynamically compensate the reactive power in the power system have their own shortcomings.

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