Control method for preventing frequency of pure DC networking power grid from being seriously deviated

Abstract

The invention discloses a control method for preventing the frequency of a pure DC networking power grid from being seriously deviated, which is characterized by comprising the step of emergently changing DC power of the pure DC networking power grid when a serious fault occurs through a DC system additional control method so as to prevent the frequency of the pure DC networking power grid from being seriously deviated after the serious fault and avoids a third defense line of the power grid from acting. Furthermore, the pure DC networking power grid refers that the power grid is connected with other power grids all through a DC transmission system, the DC system additional control method refers to frequency limitation control of direct current, and the operation of emergently changing the DC power for the pure DC networking power grid refers that the DC power is changed through frequency limitation control of the DC system. According to the invention, the power output of the DC transmission system is changed timely, and the frequency of the DC networking power grid is prevented from being seriously deviated. The control method disclosed by the invention has the characteristics of flexible operation control, ability of knowing normal operations of the power grid, economy and the like.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a control method for preventing serious frequency deviation of a pure direct current network grid. Background technique [0002] With the rapid development of the economy, the demand for electricity in the national economy is getting higher and higher, and there is a serious imbalance in the supply and demand of power resources in our country. For example, areas with relatively rich hydropower and thermal power resources are mostly concentrated in the west and southwestern regions of our country. However, the available power resources in the eastern and southeastern regions with high power demand are very limited, forcing the long-distance, large-capacity DC transmission system to develop rapidly with its own advantages. my country's ultra-high voltage and ultra-high voltage DC transmission systems The rapid development enables power resources to be efficiently and safely ...

AI Technical Summary

Problems solved by technology

The problem of low-frequency oscillation between Yunnan power grid and the external grid will disappear, but the accompanying problem is that the frequency problem of the pure DC network grid will become more and more prominent, because the DC usually adopts a constant power control method during normal operation, that is, it is connected to the external grid. The switching power is relatively fixed. If the pure DC power grid loses the large power supply of a large power plant or a DC blocking fault, the frequency will shift, especially when a serious DC bipolar multi-pole blocking fault or a combined fault of the DC system occurs. The system frequency will be seriously shifted, and the frequency shift may directly lead to the action of the third line of defense of the system, the action of the high frequency cutting machine or the low frequency load shedding device

The action of the third line of defense will cause the system to lose a large amount of load or power, which is extremely detrimental to the economy and safety of system operation.

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