Composite direct-current power flow controller with fault current limiting and circuit breaking functions

Abstract

The invention provides a novel inter-line direct-current power flow controller topology with a fault current limiting function. The topology mainly comprises thyristors forming an H bridge, a power flow control part and a current limiting part. Through the on-off control of thyristors forming an H bridge, the directions of line currents flowing into the power flow control part and the current limiting part are ensured to be from left to right. The power flow control part and the current limiting part have an overlapping area and share a capacitor branch. When the controller operates in a powerflow control mode, the thyristors T1a to T7a and T1b to T7b are turned off, the rapid mechanical switches UFD1 to UFD4 and the auxiliary switch tubes V1a, V2a, V1b and V2b are turned on, power flow control is carried out on the two lines, and capacitors C10, C11, C20 and C21 on the lines carry voltage. And when a single-pole short-circuit fault occurs in a certain line, the power flow control mode is closed, the on-off of a thyristor of the corresponding line is controlled by utilizing the voltage of a line capacitor, and an inductor L is connected in series into the fault line for current limiting and matches a direct-current circuit breaker on the line. When the circuit breaker cuts off the fault current, the inductor L is bypassed, so that the suppression effect of the inductor on theattenuation of the fault current is avoided.

Description

technical field [0001] The invention belongs to the technical field of power transmission and distribution, and in particular relates to the topology of a novel line-to-line DC power flow controller with fault current limiting. Background technique [0002] Due to its advantages in long-distance power transmission and solving the problems of large-scale renewable energy grid integration and consumption, flexible DC transmission technology has developed rapidly in recent years. The high voltage direct current grid (HVDC Grid) based on flexible DC transmission is a new technology, which can interconnect renewable energy with traditional energy in a wide area, and fully realize multiple energy forms, multiple time scales, and large space spans. The complementarity between them is one of the important development directions of the future power grid. The failure of the DC line will pose a serious threat to the safe and stable operation of the flexible DC grid. At present, the p...

AI Technical Summary

Problems solved by technology

The literature "Composite device for power flow control and short-circuit control of DC power grid" combines the inductance-shared inter-line power flow controller with DCCB, and proposes a composite device with the functions of DC power flow control, fault current limiting and circuit breaking, using coupled inductors for energy Transmission and fault current limiting, but this topology is only suitable for two lines connected to the same converter station

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