Active control current-limiting system for fault current and control method thereof

Abstract

The invention discloses an active control current-limiting system for fault current and a control method thereof. The active control current-limiting system comprises series DVR modules, DC-links and a parallel converter, wherein a series side is formed by a three-single-phase structure; each phase comprises an L, a C1 filter link, a series transformer T, one DVR module and one DC-link; an each DC-link comprises a current-limiting inductor L1, a bleeder resistor rf, a D5 and a bidirectional thyristor T3. LC filters are used for filtering out harmonic waves, and the input time of the bleeder resistors is controlled through regulating the duty ratios of controlled tubes T2, so that current is limited below a specific value. Stabilized capacitors C are connected between the three-single-phase series side and the PWM parallel converter in parallel; and the PWM parallel converter is formed by a three-phase full bridge. Improvement of the voltage quality of a power network system, governance of harmonic current and a short-circuit fault current limiting function can be achieved and the electric security is improved.

Description

technical field [0001] The invention belongs to the field of electric power technology, and relates to a fault current active regulation type current limiting system based on a unified power quality controller and a control method thereof. Background technique [0002] With the development of my country's national economy, the rapid growth of power system load has led to the continuous increase of short-circuit power and short-circuit capacity of the power grid, and the short-circuit fault current is very harmful to the safe and stable operation of the power system; nonlinear devices and impact loads Widely used in industry, it causes distortion of grid current and voltage waveforms, and the rapid increase of electrical equipment sensitive to power quality, people's requirements for power quality are becoming more and more stringent. Therefore, limiting short-circuit current, improving the safety and reliability of power system operation, and providing high-quality electric e...

AI Technical Summary

Problems solved by technology

However, the series reactor of the busbar can only realize the fault current limiting function. The reactor is connected in series in the grid for a long time, which wastes the power of the grid, and the parameters of the series reactor should not be too large, resulting in insufficient current limiting effect; or the research on the bridge current limiter There are also many, but the device reuse rate is low, the cost is high, and the general current limiting technical solution cannot improve the power quality

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