DC circuit breaker based on semi-controlled power electronic devices

Abstract

Disclosed is a DC circuit breaker based on half-control electric-power electronic devices. The DC circuit breaker includes an initial current circuit (4) and a fault current blocking circuit (8). A first lead-out terminal of the initial current circuit (4) and a first lead-out terminal (14) of the fault current blocking circuit (8) are connected with one end of a DC power transmission line after being connected. A second lead-out terminal of the initial current circuit (4) and a second lead-out terminal (15) of the fault current blocking circuit (8) are connected with the other end of the DC power transmission line after being connected. The initial current circuit (4) includes a mechanical switch module and an electric-power electronic module. The fault current blocking circuit (8) includes a plurality of capacitor modules, a plurality of half-control-device modules and a diode module.

Description

technical field [0001] The invention relates to a circuit breaker, in particular to a DC circuit breaker topology. Background technique [0002] Fast DC circuit breaker is one of the key equipment to ensure the stable, safe and reliable operation of DC power transmission and distribution system and DC grid system. Different from the AC system, the current of the DC system does not have a natural zero-crossing point, so the natural zero-crossing point of the current cannot be used in the DC system like the AC system. Therefore, the breaking of the DC current has always been a problem worth studying. topic. [0003] At present, there are usually two ways to break the DC current. The first is a pure power electronic circuit breaker, such as the patent CN102870181A applied by ABB, which can turn off the power electronic device by using high power and directly break the DC current. Although the solid-state circuit breaker manufactured by this principle can meet the requirements...

AI Technical Summary

Problems solved by technology

Different from the AC system, the current of the DC system does not have a natural zero-crossing point, so the natural zero-crossing point of the current cannot be used in the DC system like the AC system. Therefore, the breaking of the DC current has always been a problem worth studying. Subject

However, when the capacitance value is large, the breaking speed will be affected

[0007] ABB company patent WO2011141054A1 proposes a hybrid circuit breaker, in which a mechanical switch and a power electronic full-control device are connected in series on the main path, and the other bypass is composed of a surge arrester and a crimping IGBT connected in parallel. When a fault current is detected, the crimping on the bypass The IGBTs are all turned on, and then the power electronic full-control devices on the main path are disconnected, and the mechanical switch is also turned off. After the mechanical switch is completely turned off, the crimping IGBT is turned off, and the arrester is connected to the circuit to suppress the short-circuit current. This kind of open circuit The breaking speed of the circuit breaker is fast, but the sum of the pressure-connected IGBT withstand voltage of the entire bypass must be greater than the initial voltage of the DC transmission line, which requires a large number of pressure-connected IGBTs in series, resulting in a higher cost for the entire DC circuit breaker

[0008] Moreover, the main circuits of the above two patents must use full-control switching devices in series with mechanical switches, resulting in large conduction losses in normal conditions.

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