Event Detection Based Voltage and Frequency Restoration for Mobile Emergency Energy Storage Vehicle without Communication

Mobile emergency energy storage vehicle (MEESV) is important in emergency rescues, disaster relief and some important national events. Due to the capacity limitation of a single energy storage equipment, it usually needs multiple MEESVs to run in parallel as emergency power supply. Besides, in an emergency, the power supply of MEESVs can hardly use communication lines to regulate the bus voltage and frequency, where droop control is usually adopted. However, the droop control would result in voltage magnitude and frequency deviation, which requires voltage-frequency restoration to ensure the system stability. The parallel system of multiple MEESVs also needs to ensure voltage-frequency restoration of each MEESV starts at the same time. Usually, the distance between MEESVs and loads is short, and hence the voltage of point of common coupling (PCC) is easy to obtain, which is a reasonable source for event detection. Therefore, this paper proposes a voltage-frequency restoration for MEESVs based on PCC voltage detection without communication. The deviation of PCC voltage magnitude and frequency is used as a synchronization signal for the voltage-frequency restoration of each MEESV, realizing the synchronously start of the voltage-frequency restoration control of each MEESV. Moreover, the method advantages in reactive power sharing. The feasibility effectiveness of the proposed control strategy is verified by simulation and experimental results.