A Multi-terminal Coordinated Control and Protection System for Flexible DC Grid

Abstract

The invention discloses a multi-end coordination control and protection system for flexible direct-current power grids. The multi-end coordination control and protection system has the advantages thata multi-end coordination control device, pole control devices, pole protection devices, bus protection devices, line protection devices, a direct-current station control device, an alternating-current station control device, a grounding resistance monitoring device, a conversion transformation protection device, an alternating-current energy dissipation device and a safety and stability control device in the multi-end coordination control and protection system are connected with control bus, and accordingly data can be shared among the multi-end coordination control device, the pole control devices, the pole protection devices, the bus protection devices, the line protection devices, the direct-current station control device, the alternating-current station control device, the grounding resistance monitoring device, the conversion transformation protection device, the alternating-current energy dissipation device and the safety and stability control device; voltages and power of the integral grids can be controlled by the multi-end coordination control and protection system, equipment such as bus, direct-current lines and conversion transformation equipment can be protected in real time, short-time absorbed transient energy can be inputted by the alternating-current energy dissipation device when new energy cannot be outwardly delivered due to island delivery-end single-pole locking or receiving-end converter station faults in the flexible direct-current power grids, then generator tripping can be carried out on the new energy by means of safety control, and accordingly the problems of overload, power surplus and the like of power grids due to the fact that existing new energy cannot be outwardly delivered when the existing flexible direct-current power grids are in island operation modes can be effectively solved by the aid of the multi-end coordination control and protection system.

Description

technical field [0001] The invention relates to the technical field of electric power systems, and more specifically, relates to a multi-terminal coordinated control and protection system of a flexible DC power grid. Background technique [0002] The flexible DC grid is a grid-like power transmission system that is interconnected by multiple converters on the DC side through DC lines with DC switches. The flexible DC grid can realize large-scale power flow distribution and control, enhance the flexibility and reliability of the entire system, and provide redundant capacity for the power system through resource sharing. [0003] In the flexible DC grid, the failure of busbars, DC lines, converters, converter transformers and other equipment may lead to the limitation of grid transmission power. In particular, when there is a single-pole blockage at the sending end of the island or a serious failure of the converter station at the receiving end, there will be a power surplus ...

AI Technical Summary

Problems solved by technology

[0004] In view of this, the present invention discloses a multi-terminal coordinated control and protection system of a flexible DC power grid to solve problems such as excessive voltage or power surplus in the flexible DC power grid in an island operation mode, thereby avoiding damage to DC devices

Images