Reactor type short-circuit fault current limiter

Abstract

A reactor-type short circuit fault current limiter, comprising a first reactor (L1), a second reactor (L2), a switch (K1), a capacitor (C1) and arresters (H1, H2 and H3). The first reactor (L1) consists of a first winding (L11) and a second winding (L12) by intercoupling through a magnetic circuit, one end of the first winding (L11) and one end of the second winding (L12) are connected in parallel to each other at a first connection point (a), and the other end of the first winding (L11) is connected in series to the switch (K1) and then connected in parallel to the other end of the second winding (L12) at a second connection point (b). When the power grid is in a steady state, a current limiter works in a series resonance or series compensation state, and presents a low impedance; when the power grid has a short circuit fault, the windings of a reactor undergo overcurrent saturation, and at the same time, the reactance change of the reactor is controlled by closing a switch, so as to produce a high impedance to achieve fault current limiting. The current limiter enhances the current limiting capacity, reduces the system manufacturing cost, has insignificant impact on the power grid, and improves the operational safety and reliability of the power grid.

Description

technical field [0001] The invention relates to a short-circuit fault current limiter, in particular to a fault current limiter for transmission and distribution networks. Background technique [0002] With the rapid development of the national economy, the society's demand for electricity continues to increase, which drives the continuous development of the power system. The capacity of single machines and power plants, the capacity of substations, and the load of cities and industrial centers continue to increase, which makes the interconnection of power systems , the level of short-circuit current in the power grid at all levels is increasing continuously, and the destructiveness of short-circuit faults to the power system and its connected electrical equipment is also increasing. Moreover, while the demand for electric energy is increasing day by day, people also put forward higher requirements for power quality, power supply reliability and security. However, the trans...

AI Technical Summary

Problems solved by technology

Because the current limiting capacity of the PTC current limiter is too small, the resonant current limiter is accompanied by high voltage generation during the current limiting process, which has great potential safety hazards, so none of them have application prospects in the actual power grid.

When the solid-state current limiter is applied in a high-voltage and large-capacity system, it needs a large number of solid-state switch tubes (IGBT, GTO, etc.) Applications are also very limited

The superconducting current limiter can pass a large current during normal operation and present only a small impedance or even zero impedance, and only presents a large impedance during a short-circuit fault, so its current limiting effect is very obvious, but the cost is extremely expensive

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