A hierarchical control scheme to integrate the telecom backup systems into microgrid

This paper presents a novel hierarchical control scheme to integrate the telecom backup systems into power grid through microgrid. The proposed scheme employs hierarchical control system to correctly control the system in both grid-connected and islanded modes. The conventional hierarchical control system is highly dependent on communication links. With no communication link, the reliability and efficiency of the system degrades significantly. This paper proposes a novel hierarchical control scheme that is less relies om communication links and performs adequately even with no communication link. For the secondary control level, an innovative adaptive droop control scheme that regulates microgrid parameters locally is proposed. This approach needs neither an extra controller nor a communication link. To reduce the voltage measurement errors, the effect of line impedance between converter and Point of Common Coupling (PCC) has been taken into account in voltage adaptive droop controller. In addition, the proposed scheme offers two operation modes of autonomous and non-autonomous. In autonomous mode, the active/reactive power is controlled based on the grid parameters and available storage capacity without a need to communication link. While in non-autonomous mode the active/reactive power reference is provided by tertiary controller. With no tertiary controller in service, the proposed controller operates in the autonomous mode and controls the active/reactive power itself to ensure the stability of the power grid. The performance of the proposed controller is evaluated by using simulation results.