Reliability in power conditioners/battery installation

Both availability and maintainability are enhanced for multi-megawatt battery storage installations if modular design is employed. A module is defined as an inverter/battery charger and an array of battery cells. The designer has several trade offs to consider for the number of cells in series and the size of each inverter/battery charger. Fault tolerant system designs allow for the limited life expectancy of battery cells and produce reliable systems. The selection of ten or more modules operating in load sharing and redundancy is an order of magnitude more reliable than a single module rated for the total capacity of an installation. Frequent testing will assure the proper functional status of redundant modules. Inverters that serve as AC current sources and are phase locked to the utility voltage and frequency provide simplicity and reliability. A current source inverter reacts quickly to loss of utility voltage and has other noteworthy safety embellishments