Autonomous control of energy storage devices for enhancing power system stability

In recent years, due to petroleum price going-up and the increasing interest of wholesale wheeling alternatives open to third-party generations as wind power etc., the problems about power system instability grow into a serious matter. For making better use of those green powers but without system instability, an autonomous control basing on multiple energy-storage devices (ESDs) is proposed. Where, each ESD only respects to a simple rule as well as its individual controller to determine charging or discharging. Through such an autonomous control to ESDs, the change of total injection power of an area can be minimized. That is, system stability can be enhanced. In addition to extend the ESD control to interconnected systems where are with multiple machines and tie lines, the considerations about area control error (ACE) and automatic generation control (AGC) are also combined into this control. Since the proposal for ESD control is particular useful in solving the problems involving with multi-machine and multi-tieline systems, a three-machine seven-bus two-loop testing system is given to confirm the effectiveness and show the function of it.