Power determining method for battery energy storage system stabilizing wind power grid connection power fluctuation

Abstract

The invention provides a power determining method for a battery energy storage system stabilizing the wind power grid connection power fluctuation. The method comprises the step one of determining a control period and obtaining the power output range of the power of a wind storage grid connection system within the next control period; the step two of obtaining the power output range, used for the smooth wind power, of the energy storage system; the step three of obtaining the actual energy storage power output range; the step four of determining the optimum energy storage power output set value within the actual energy storage power output range. The method solves the problem of set value lagging caused by the inertia time constant of a low-pass filter and improves the efficiency of stabilizing the wind power fluctuation of energy storage.

Description

technical field [0001] The invention relates to a method in the field of electrotechnical technology, in particular to a method for determining the power of a battery energy storage system for smoothing wind power grid-connected power fluctuations. Background technique [0002] In order to ensure the balance of power supply and demand and the security of the power grid, the large-scale and high-frequency fluctuations of wind power have brought great adjustment pressure and burden to other power sources in the power system. Therefore, my country's "Technical Regulations for Connecting Wind Farms to the Grid" has the following regulations on the maximum power change rate of wind power: wind farms should limit the change rate of output power. The maximum power change rate includes 1min power change rate and 10min power change rate, the specific limits can refer to the table below. [0003] Table 1 is the recommended value of the maximum power change rate of the wind farm [0...

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Problems solved by technology

This method effectively suppresses wind power fluctuations, but does not take into account the state of charge (SOC) of the energy storage system, which may easily cause overcharging and overdischarging of the energy storage system

At the same time, the filter parameters of this method need to be designed offline in advance, and the designed filter parameters are difficult to adapt to the smoothing requirements of wind farms in different seasons, different locations, and different climates. That is to say, in different scenarios, according to the historical data of wind power fluctuations, Redesign the filter, the adaptability is relatively poor

In the public documents "Optimal control of battery energy storage for wind farm dispatching" and "Control strategies for battery energy storage for wind farm diapatching", SOC and low-pass filter are combined, and the time constant is adjusted by introducing SOC feedback, but the time constant The adjustment method is relatively simple, neither dynamic and targeted adjustment is made according to the SOC size, nor is it adjusted according to the smoothing target of wind power fluctuations

Therefore, this method is also difficult to ensure that the change rate of wind power grid-connected power complies with relevant standards.

[0006] In general, the current energy storage power control for smoothing wind power fluctuations is mainly based on the low-pass filter method, and the filter time constant is adjusted after the fluctuations appear to suppress wind power fluctuations, so this method has great inertia and hysteresis

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