United planning method for grid connection of offshore wind power plant and expansion of shore power grid

Abstract

The invention proposes a united planning method for grid connection of an offshore wind power plant and expansion of a shore power grid, and belongs to the field of power system power grid planning. The method comprises the steps of clustering active power output data of each offshore wind power plant over the past year to obtain a plurality of typical scenes; building a united planning model forgrid connection of the offshore wind power plant and expansion of the shore power grid under multiple scenes by taking minimum sum of equivalent annual values of construction costs of a seabed cable,a boost station, a reactive compensation device and a shore expansion overhead line and power generation cost of a machine set in the whole power grid after the network loss is considered; and solvingthe model to obtain an optimal planning scheme. With the planning scheme obtained by the invention, the utilization ratio of a circuit and equipment can be improved, shore power grid and offshore wind power running are more coordinated, the power grid running difficulty is reduced to reduce wind abandoning, and the more excellent power grid running effect is achieved.

Description

technical field [0001] The invention belongs to the field of electric power grid planning, and in particular relates to a joint planning method for grid connection of offshore wind farms and expansion of onshore power grids. Background technique [0002] In recent years, my country's offshore wind power is in a period of rapid development, both in terms of quantity and installed capacity, which have greatly increased compared with before. Taking the construction of offshore wind farms in Jiangsu as an example, Jiangsu Province completed the construction of 18 offshore wind farms from 2014 to 2016, with a total project scale of 3.4897 million kilowatts. The access of large-scale offshore wind power makes the grid connection of offshore wind farm clusters and the expansion of onshore power grids an important issue. [0003] The grid-connection of offshore wind farms requires the offshore wind farms to be clustered, connected to the offshore booster station, then connected to ...

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Problems solved by technology

[0004] The existing offshore wind farm clusters and onshore transmission network expansion methods have the following problems: First, they use the original main grid nodes directly as onshore booster stations, but in reality, there may be no grid-connected points on the coast that can be connected. Site selection and capacity determination for the new shore booster station

Second, in the original method, the voltage level of the submarine cable from the offshore step-up station to the grid connection point is selected as a fixed voltage level, and directly determining the voltage level will cause low or unsafe equipment utilization due to over- or underestimation

Third, the original method used the installed capacity of each wind farm as the active output of the wind farm during optimization, but in practice, the active output of offshore wind farms has strong correlation and volatility, and the actual active output of multiple wind farms clustered The output is smaller than the installed capacity of the wind farm, and the active power output is reduced due to the low load level. Therefore, optimization according to the wind farm capacity will result in low utilization of the line and booster station equipment, waste of investment, and unreasonable planning scheme

From these two aspects, this method generally cannot obtain the optimal solution to the problem, which may lead to waste of investment and low utilization of equipment, and the planning scheme is unreasonable

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