东北电力大学工程硕士学位论文
II
Abstract
Compared with AC power transmission, HVDC power transmission has many advantages,
such as low line loss and no system synchronization stability. With the rapid development of
multi-end flexible DC transmission and distribution technology and high-voltage voltage source
converter technology in recent years, DC circuit breakers are playing an increasingly important
role in the DC grid. In the event of a fault, the DC circuit breaker needs to complete the action
within the specified time and remove the fault to limit the short circuit current. Therefore, the DC
circuit breaker is an indispensable basic equipment for the development of the future DC grid. At
present, the research and development of high-voltage DC circuit breakers are mainly restricted
by the following points: In DC transmission, there is no natural zero-crossing point in the DC
current, which results in the arc not easily extinguished during the opening process; after the DC
current is opened, the system will generate The voltage phenomenon can easily lead to the
component being burned out. At the same time, during the removal of the fault current, a large
amount of energy stored in the system needs to be absorbed by the discharge. Compared to the
AC system, the DC system impedance is very small (in the steady state, only the resistance).
Therefore, the short circuit current rises rapidly. This requires the DC circuit breaker to
accurately cut the fault within milliseconds and remove the fault. The current research and
development of DC circuit breakers include mechanical DC circuit breakers, all-solid-state DC
circuit breakers, and hybrid DC circuit breakers.
Firstly, this article describes the current development of DC circuit breakers in domestic and
foreign, and studies and summarizes new DC circuit breakers currently under study. The current
problems of DC circuit breakers are pointed out. In view of the shortcomings of the existing
hybrid DC circuit breakers, this paper presents a new type of DC circuit breaker topology
scheme and control strategy.
Secondly, a detailed analysis and comparison of the hybrid energy HVDC circuit breaker
proposed by ABB and the energy absorption characteristics of the new DC circuit breaker
proposed in this paper are introduced. The internal control principle of the hybrid DC circuit
breaker is introduced and deduced. Out of its action criteria. The outstanding feature of this new
type of DC circuit breaker topology is that a hybrid structure of a mechanical switch and a solid
state switch is used. While retaining the good static characteristics of the mechanical switch and
the good dynamic characteristics of the solid state switch, the rated voltage and the energy
consumption capacity of the DC arrester is greatly reduced. Thereby reducing the manufacturing
cost of the circuit breaker; at the same time, the program further increases the current cut-off
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