Power quality, also known as grid quality, grid voltage quality or service reliability, is a topic that is directly linked to energy supply and is certainly a highly topical issue in this field.

Due to the liberalization of power markets, grid-bound energy sources, such as electrical current, became freely tradable products and thus have to obey product liability law as do other tradable products. The corresponding parameters were constituted in the product standard EN 50160 in Europe. Additionally, there are many other tasks: e.g. special harmonics evaluations, long-term measurements, and the identification of fastest transient processes or only power flow measurements in four quadrants.

Task

The identification of limit values that are constituted in the EN 50160 or in another power quality standard is nowadays not a big challenger anymore. Several millimeters can measure these, compare their values with limit values and reflect them in well-formatted reports.

The task becomes more specialized when you want to find the reasons for off-limit conditions; that is when you want to make exact analyses of the national grid. For very fast transient processes as they can appear in low voltage grids, sampling rates of 6,4 kHz are not sufficient. 1 million data points per second are necessary in this case.

• 1 Msamples/sec

The analysis of harmonics up to the 25^th is sufficient for the EN 50160 but other standards demand 50 or even 100. Latest standards even proceed to the range of 9 kHz in order to identify disturbances of electrical instruments (200 Hz bands of 2 to 9 kHz).