Synchronization method for grid integrated battery storage systems during asymmetrical grid faults

Bane Popadic, Vladimir Katic, Boris Dumnic, Dragan Milicevic, Zoltan Corba
2017 Serbian Journal of Electrical Engineering  
This paper aims at presenting a robust and reliable synchronization method for battery storage systems during asymmetrical grid faults. For this purpose, a Matlab/Simulink based model for testing of the power electronic interface between the grid and the battery storage systems has been developed. The synchronization method proposed in the paper is based on the proportionalintegral resonant controller with the delay signal cancellation. The validity of the synchronization method has been
more » ... d using the advanced laboratory station for the control of grid connected distributed energy sources. The proposed synchronization method has eliminated unfavourable components from the estimated grid angular frequency, leading to the more accurate and reliable tracking of the grid voltage vector positive sequence during both the normal operation and the operation during asymmetrical grid faults. 114 utility grid. However, this solves the immediate issue only partially, especially for the distribution network operator (DNO), where it represents a semicontrollable intermittent and limited energy source. A different possibility, and a more reliable one, would include distributed systems constantly accessible by the DNO. In that regard, researchers currently investigate several energy storage technologies to be used: ̶ Compressed Air Energy Storage -CAES, ̶ Thermal energy storage, ̶ Flywheel, ̶ Hydraulic and Hydro-accumulation (pump-hydro) storage, ̶ Electrolytic energy storage, ̶ Electro-chemical sources -batteries, ̶ Superconducting Magnetic Energy Storage -SMES, etc. Currently, the most dominant technology for energy storage is based on electro-chemical sources, holding important advantages like the existing industry, cost-efficiency, developed technology, etc. Nevertheless, their full success has been hindered by insufficiencies such as high sensitivity, short battery life span, high price and environmental concerns [1]. Battery based storage system control needs to have high efficiency and dynamic performance, facilitating the least possible operation price. Having different algorithms impacting battery storage system output variables differently, advance methods can even aim to extend the battery lifespan (lowering the polarization effect) [2] . Constant voltage (CV) and constant current (CC) techniques present the foundation for all advanced charging methods, usually based on the hybrid CC-CV techniques [3] . The referent values and the duration, for these hybrid methods, can be calculated using some of the most advanced techniques for process optimization, including Ant Colony algorithm, Gray prediction algorithm and Particle Swarm Algorithm [4 -6]. The control of the references is performed by different strategies and topologies like resonant controllers, hysteresis current controller, proportional-integral-derivative (PID) controller, artificial neural networks, fuzzy-logic controller and others [4, 7] . With the benefits of energy storage technologies and the subsequent increase in energy efficiency, a reliable, sustainable and economical supply can be achieved. However, the integration of the former can have adverse impact on the power quality of the system. A large number of power electronics components, introduced for the battery charging and discharging control, usually operate in a non-linear mode emphasizing this issue [8] . Therefore, advanced control strategies need to be researched, allocating special attention to the effects of battery chargers on the power quality.
doi:10.2298/sjee1701113p fatcat:2rutfaljpzgwbnmwtiv6zb2iv4