A protection configuration method suitable for multi-terminal flexible substations

Abstract

The invention discloses a protection configuration method suitable for a multi-terminal flexible substation. The method is: divide the multi-terminal flexible substation into: the protection area before AC, the protection range is from the incoming line of the AC power source to the outgoing line of the modular multi-level converter; the protection area before the DC, the protection range is the outgoing line of the modular multi-level converter. To DAB incoming line; DAB protection area, the protection range is from DAB incoming line to DAB outgoing line; DC post protection area, the protection range is from DAB outgoing line to inverter incoming line; AC post protection area, the protection range is from inverter outgoing line to AC Load incoming line; for different protection zones, different protection strategies are adopted to protect multi-terminal flexible substations. The invention can freely access the DC power supply, reduces the occurrence of the phenomenon of abandoning light and abandoning wind when new energy sources such as wind power and photovoltaics are connected to the grid, and completely protects the multi-terminal flexible substation, and can flexibly adapt to the multi-power electronic device situation of the multi-terminal flexible substation.

Description

Technical field [0001] Technical Field The present invention relates to a power system protection, particularly suitable for multi-terminal is protected by a flexible configuration of the substation. Background technique [0002] With the rapid development of new energy technologies, large-scale photovoltaic and wind power grid operation. Multiport flexible substation compared with the original method after a new energy grid inverter can be new energy after a transformer directly into DC power, eliminating the cost of construction of the inverter station. DC-DC distribution network portion of the flexible circuit are only several hundred kilometers and two AC input and output ports, and a plurality of port multiport flexible substation, line length and only a few kilometers, these features make the flexible multi-terminal protection can not copy substation flexible DC distribution network, Traveling wave no longer applies where multiport interface. The flexible characteristics of...

AI Technical Summary

Problems solved by technology

The DC line part of the flexible DC distribution network has hundreds of kilometers and only two AC input and output ports, while the multi-terminal flexible substation has multiple ports and the line length is only a few kilometers. These characteristics make the protection of the multi-terminal flexible substation impossible to copy Flexible DC distribution network, traveling wave protection is no longer suitable for multi-terminal interfaces

According to the characteristics of flexible substations, longitudinal differential protection can protect multi-terminal lines, but this cannot cover the entire length of the line, and cannot protect lines other than current transformers

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