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Hybrid Energy Storage System for Stationary Applications
To solve the above mentioned problems, we propose the Hybrid Energy Storage system (HESS) incorporating supercapacitors in addition to batteries. Cost analysis of electrochemical storage systems based on batteries of different types, supercapacitors and their combination has also been carried out.
To verify the main principles of the proposal, we have designed and developed a HESS prototype. The main functional characteristics of the developed HESS were studied experimentally.
The prototype bases on Li-ion batteries and supercapacitors. Such energy storage system includes three main components: Li-ion batteries, supercapacitors, and grid interconnection consisting of two invertors and control and monitoring system. Energy storage capacity of developed HESS prototype is 100 kWh, nominal power—100 kW, peak power—200 kW. HESS was created and tested within the experimental facility including 1.5 MW gas turbine power plant, 200 kW controllable active and reactive loads, and a control and measurement system.
Experimental results showed that HESS successfully provides the following functions: (i) suppression of voltage, current, and frequency disturbances in the grid; (ii) compensation of reactive power in the circuit; (iii) uninterrupted power supply. In comparison with battery storage system without supercapacitors, HESS shows lower cost, and higher peak power. In hybrid energy storage system the presence of supercapacitors allows to shave peaks of power at the charge and discharge mode of the battery.
We believe that this feature of HESS will prolong the life time of batteries and thus increase the life time and reliability of the entire system.