HVDC (high-voltage direct current) system fault current limiting device and method based on saturated core

Abstract

The invention provides an HVDC (high-voltage direct current) system fault current limiting device and method based on a saturated core. On the basis that high inductance can effectively limit currentrising rate, variable inductance is produced automatically before and after the fault with application of the nonlinear principle of magnetization of a soft magnetic material in the method to limit DCfault current gradient, and DC fault current can be effectively cut off at the early stage through cooperation with a circuit breaker. By means of reasonable design for material, length and cross section of a core, material and length of a permanent magnet and turns of winding coils, operating characteristics of the current limiting device in a normal state are consistent with those of a smoothing reactor, and the current limiting device in a fault state can effectively limit fault current rising rate at the early stage of the fault. The device and the method have advantages as follows: the device has good effect for limiting the high rising rate of fault current at the rising stage, can effective cut off fault current at the early stage of the fault when cooperating with the DC circuit breaker, and can be taken as the smoothing reactor to stabilize current of a DC system when in the normal state.

Description

technical field [0001] The invention belongs to the field of high-voltage direct current current limiters, and in particular relates to a high-voltage direct current system fault current limiter and method based on a saturated iron core. Background technique [0002] Due to the growing demand for energy and due to economic, environmental and political considerations, the ride-through of distributed power in traditional grids is growing rapidly. Compared with the traditional AC system, the DC system has an absolute advantage in long-distance large-capacity power transmission. The main reason is that the DC-linked system does not have to keep frequency consistent, which leads to better reliability and higher efficiency of the grid. In addition, DC system costs are much lower than AC while transmitting the same power. [0003] However, the research results of the UHV DC grid initiated by the International Power Grid Organization show that due to the low resistance and reactan...

AI Technical Summary

Problems solved by technology

However, SFCL requires a superconducting device and a corresponding harsh environment, making it difficult to apply to practical systems

SSFCL's complex control strategy and relatively low device withstand voltage level make it unsuitable for high-voltage DC systems

Therefore, it is necessary to find a feasible method to fill the field gap brought by the traditional method not suitable for HVDC system

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