Direct current circuit breaker and circuit breaking method for direct current power transmission system

Abstract

The invention provides a direct current circuit breaker used for controlling on-off of a high-voltage direct current power transmission system. The direct current circuit breaker comprises a control system, a protection branch, and a through-flow circuit and an LC forced transfer circuit which are in parallel connection, wherein the through-flow circuit consists of a circuit breaker body and an electric power diode which are connected in series; the LC forced transfer circuit consists of a first pre-charging capacitor, a first inductor and a thyristor which are connected in series; the response time of the thyristor is shorten than that of the circuit breaker body; the protection branch is used for performing voltage clamping when the voltages at the two ends of the through-flow circuit and / or the LC forced transfer circuit are greater than or equal to a voltage set value; the control system is used for controlling the on-off of the through-flow circuit and the LC forced transfer circuit; and the control system is used for transmitting a conduction signal to the thyristor before the circuit breaker body is disconnected so as to enable the current passing through the through-flow circuit to be lower than or equal to a first current set value at the disconnecting moment of the circuit breaker body.

Description

technical field [0001] The invention relates to the field of circuit breakers, in particular to a DC circuit breaker and a circuit breaking method for a DC transmission system. Background technique [0002] In recent years, due to the low cost of the DC system, no capacitive current, no eddy current loss, and easier control of the power flow, the DC HVDC transmission system has attracted much attention. Especially in some specific occasions, such as large-scale ship power supply system, urban rail transit power supply system and other DC systems have been greatly developed. At the same time, with the continuous increase of the capacity of the DC system and the continuous improvement of the voltage level, the peak value of the short-circuit current can reach more than 100kA, and the rate of increase of the short-circuit current is also more than 15A / us. Traditional mechanical circuit breakers are difficult to adapt to the development needs of high voltage and high current in...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the above problems, the present invention provides a DC circuit breaker and a DC transmission system disconnection method, taking into account the advantages of small on-state loss of mechanical circuit breakers and rapid action of all solid-state circuit breakers, which can adapt to the high voltage and high current of future DC power grids The development needs of the DC transmission network are solved due to the factor of the circuit breaker and the problem of being restricted by the development

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