Power grid whole-grid reactive power optimization method based on improved differential evolution algorithm

Abstract

The invention discloses a power grid whole-grid reactive power optimization method based on an improved differential evolution algorithm. The method is characterized by including: performing active power grid loss analysis based on load flow calculation; performing whole-grid optimization according to the grid loss analysis result and based on the improved differential evolution algorithm. The method has the advantages that the receiving and outputting capacity of a power grid to new energy is increased greatly while safe and economical operation of the power grid is guaranteed, wind curtailment is reduced, and on-grid energy of the new energy is increased.

Description

technical field [0001] The invention relates to the technical field of reactive power and voltage control in the process of large-scale new energy power generation, in particular to a reactive power optimization method for the entire power grid based on an improved differential evolution method. Background technique [0002] Most of the large-scale new energy bases generated after my country's wind power enters the stage of large-scale development are located in the "three north regions" (Northwest, Northeast, and North China). Large-scale new energy bases are generally far away from the load center, and their power needs to be transmitted to load center for consumption. Taking Gansu Power Grid as an example, as of April 2014, the installed capacity of grid-connected wind power in Gansu Power Grid has reached 7.07 million kilowatts, accounting for about 20.2% of the total installed capacity of Gansu Power Grid (35 million kilowatts), becoming the second largest after thermal ...

AI Technical Summary

Problems solved by technology

At present, the low-voltage tolerance of the wind turbine itself is very limited. At this time, the wind turbine often adopts the method of automatic cut-off for its own protection, which causes the active power imbalance of the system and affects the stability of the system; at the same time, the asynchronous generator does not have a maintenance and adjustment mechanism. terminal voltage level, and absorb reactive power from the system during operation, so the problem of voltage stability is more prominent

[0004] When the system voltage drops, if the grid cannot provide enough reactive power, the terminal voltage of the wind turbine based on the asynchronous generator cannot be rebuilt, resulting in the removal of the wind turbine by the overspeed protection or low voltage protection action of all the asynchronous wind turbines in the entire wind farm; if The protection cannot operate normally, because the terminal voltage of the wind turbine cannot be rebuilt, which will cause the transient voltage instability of the wind farm and even the regional power grid

Due to the mutual influence between the voltage and frequency of the entire power grid in the AC network system, the large changes in wind power output in Jiuquan area will inevitably cause voltage and frequency fluctuations in the entire system, resulting in further expansion of the accident

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