A DC grid architecture that does not rely on DC circuit breakers

Abstract

The invention discloses a direct current network structure independent of a direct current circuit breaker, which includes a plurality of multi-terminal HVDC transmission systems, In each multi-terminal HVDC transmission system, the power supply side is integrated into the multi-terminal HVDC transmission system through conventional HVDC transmission, the equivalent AC power network is integratedinto the multi-terminal HVDC transmission system through a series of modular multi-level converters, and the HVDC lines in the multi-terminal HVDC transmission system are serially connected with a plurality of fast mechanical switches and smooth reactors; Each multi-terminal HVDC transmission system is connected with each other through HVDC overhead lines and fault isolation equipment to form a direct current network. The direct current network structure provided by the invention is constructed by a subsystem composed of a multi-terminal direct current transmission system. Through the cooperation of a converter and a fault isolation device, the direct current network structure can quickly, flexibly and selectively handle the direct current fault without relying on the interruption of the direct current circuit breaker.

Description

Technical field [0001] The invention relates to the technical field of power system transmission and distribution, and in particular to a DC power grid architecture that does not rely on DC circuit breakers. Background technique [0002] With the rapid development of DC transmission technology, especially flexible DC transmission technology (voltage source converterbased HVDC, VSC-HVDC), the engineering community has begun to actively try to introduce multi-terminal DC and DC grid technology into traditional power grids to cope with the rapidly growing energy demand. and a profoundly changing energy landscape. [0003] DC grids will face more challenges in isolating faulty lines than AC grids. The DC circuit breaker equipment that directly corresponds to it is still some way away from comprehensive engineering applications in terms of economy and technological maturity. This is also the current DC grid architecture based on DC circuit breakers. In terms of design The main ...

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Problems solved by technology

The DC circuit breaker equipment directly corresponding to it is still far from comprehensive engineering application in terms of economy and technology maturity. This is also the current DC grid structure based on DC circuit breakers. The main bottleneck encountered when

As another alternative, although the faulty DC line can be cut off through the cooperation of the inverter with fault self-clearing capability and the high speed switch (HSS), during the fault processing, all the connected grids need to be connected. The cooperation of the converter station reduces the DC voltage, which is equivalent to a comprehensive expansion of the fault range. Therefore, this design scheme is only applicable to the small-scale multi-terminal DC transmission field, and it is difficult to directly expand it to the DC grid level.

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