{'fraction_non_alphanumeric': 0.016351118760757316, 'fraction_numerical': 0.0, 'mean_word_length': 5.533707865168539, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Flywheel energy storage systems for power systems application

The ever increasing penetration of renewable and distributed electricity generation in power systems involves to manage their increased complexity, as well as to face an increased demand for stability and power quality. From this viewpoint, the energy storage plays a key role in the reliability and power quality of the power systems. Several energy storage technologies have been recently adopted to meet the various demands of power systems. Among them, due to their advantages of rapid high round trip energy efficiency and long cycle life, flywheel energy storage systems are today used in load leveling, frequency regulation, peak shaving and transient stability. This paper reports an in-depth review of existing flywheel energy storage technologies and structures, including the subsystems and the required components. The performance metrics in designing and manufacturing of flywheel-based energy storages in power systems, along with safety and cost considerations, are also discussed. Finally, challenges and trends of flywheel energy storage solutions in future scenarios are presented.