Battery energy storage systems . Greater protection against fires.
Battery energy storage systems (BESS) are now making a decisive contribution to electromobility, remote supply (islanding) for the integration of renewable energies , for the optimisation of energy use and grid system services. Falling system and technology costs, especially for lithium-ion batteries , are favouring their development as an alternative to conventional storage technology such as hydroelectric power plants.
Power generation , transmission and distribution networks undoubtedly form an important infrastructure on whose operation the economy in general, public institutions and domestic economies depend. Battery energy storage systems play a fundamental role in these important infrastructures.
System availability depends on the availability of the energy storage systems used. Fire load is directly related to the amount of energy stored in a lithium-ion battery . The higher the energy stored, the longer it will last and the larger the potential fire. Once a fire occurs, it is usually not over until the stored energy has been completely consumed or released. A fire can be caused by electrical, mechanical or thermal failures. For this reason, energy storage system manufacturers provide extensive fire protection features and are constantly looking for new and improved fire protection solutions.
An isolated grounded network (IT system) is used when installing a power supply system. This provides the basis for high availability and improved fire protection right from the system design stage.
In order to take advantage of the inherent advantages such as high availability and improved fire protection of an IT system, it must be planned in the system design. This decision is simplified by the fact that a transformer can be useful in industrial battery energy storage systems due to higher power or connection to a higher voltage level. This galvanically isolates the battery energy storage system from the grid. In addition, the DC circuit between the battery and the converter is usually designed as an isolated ground network. One of the characteristics of the IT system is that the active conductors are not connected to ground. The enclosures of the electrical equipment remain grounded. Battery modules are connected in a row and combined in racks. The row connection results in a higher system voltage. The parallel connection of several racks increases the performance and storage capacity. The three-phase converter adopts bidirectional energy transformation (DC<->AC) and is decisive together with the battery for the power flow and its efficiency. The use of a transformer is characteristic, on the one hand, due to the connection to a higher voltage level and, on the other hand, due to the higher power. The transformer galvanically isolates the battery energy storage system from the grid. The DC circuit between the battery and the converter is usually designed as an isolated grid.
Source: Sac de Noticies Magazine. Guild of Barcelona
