The power quality analyzers that are installed in transformer substations must meet the requirements contained in EN 50160, in terms of both the parameters recorded and the format of the recorded data. For installations outside European territory, the law may differ in some regards, but it will always depend on the electrical parameters recorded by power quality analyzers.
Standard EN 50160 refers to statistics, normally averaged every 10 minutes, to ensure the regularity of the level of quality of the electrical waveform supplied. However, another aspect that can have financial effects is spontaneous quality events, whether caused by faults, technical outages or incidents in transformers or transmission and distribution lines, as these can result in customers filing administrative claims against you.
Because of this, a power quality device is required that can record events that affect the quality of service, as per the guidelines set out by the IEC 61000-4-30 international standard, such as overvoltages, dips or voltage interruptions lasting at least half a cycle. This information, registered in the transformer substations, will serve as evidence when defending against any claim for damages caused to your customers' facilities, whether due to equipment malfunctions, faults in loads or production lines, or supply outages.