A Study on Frequency Regulation Energy Storage System Design in Island Power System

Abstract

The necessity and installation of energy storage device are increasing due to the change of power system such as an increase in large-capacity distributed power source, and therefore, it is required to study the power system analysis and control method considering energy storage system (ESS). The type of grid-connected converter of the battery system is assumed to be the voltage source converter. The controller is configured to allow independent control of P and Q, as the effective power output controller of the energy storage device according to the frequency change of the power system, the droop control method using the controllable droop coefficient was used. In this paper, we compare and analyze the effects of fixed and adaptive droop control methods on the stability of the independent power system in the transient situations such as the dropout of generators. A method has been studied to improve system stability by appropriately controlling ESS using adaptive droop control. Simulations showed the adverse effects of inappropriate control on the power system stability. An adequate capacity and droop control for an ESS active power control depending on the power system operation condition has been studied, and the effectiveness of the droop control was verified by simulation. The adaptive droop control strategy can appropriately adjust the droop coefficient according to the system condition so that the ESS contributes appropriately to the stability improvement of the power system.