A combined energy storage discharge method for maintaining frequency stability of a power grid

Abstract

The invention discloses a combined energy storage and discharge method for maintaining the frequency stability of a power network, which solves the problem that the energy storage capacity of a supercapacitor and a flywheel is limited and the capacity is insufficient when charging and discharging for a long time is required. The method comprises selecting a flywheel energy storage device; selecting a storage battery energy storage device; after connecting the flywheel energy storage device and the battery energy storage device in parallel to the power grid, the electric energy storage of the two energy storage devices should be kept at about 50% of their rated capacity. When the unbalanced frequency of power supply and demand decreases, that is, when the power consumption is greater than the power generation, first starting the flywheel energy storage device to discharge; If the frequency of the power grid has been balanced before the power margin exceeds 2-3 seconds, terminating thedischarge of the flywheel energy storage device; If, the grid frequency is not balanced before the flywheel energy storage device of the remaining power capacity of 2-3 seconds, , then startting the battery energy storage device discharge to ensure the continuity of the discharge for the grid frequency modulation.

Description

Technical field [0001] The invention relates to a combined energy storage method of a battery, a flywheel energy storage, and a super capacitor, in particular to a combined energy storage method for maintaining the stability of the grid frequency in terms of power system frequency modulation, peak regulation and ACE adjustment. Background technique [0002] Wind power and photovoltaic power generation use wind and solar energy as energy sources respectively, and natural resources such as wind and solar energy are easily affected by the environment and climate, making the power of wind power and photovoltaic power generation intermittent, uncertain and volatile Features. As wind power and photovoltaic power generation are connected to the grid on a large scale, their impact on the safe and stable operation of the grid cannot be ignored. For these intermittent energy sources, the power output changes drastically. When the installed capacity increases to a certain scale, its power ...

AI Technical Summary

Problems solved by technology

[0003] The invention provides a combined energy storage method for maintaining the grid frequency stability, which solves the problem of limited capacity of supercapacitor and flywheel energy storage, and insufficient capacity when charging and discharging for a long time is required