The test may be carried out alternatively with a network simulator capable of changing the parameters of frequency and voltage available at the output terminals of the inverter, or directly to the electricity grid. In this case, performing tests are allowed by adjusting the parameters that control frequency and voltage in grid connected conditions (of parallel) so that they fall outside the allowed values. To check the minimum delay before connection (start) or reconnection after the intervention of protections, the range of allowed V and f must be reset to default (85 % Vn and 110 % Vn, 49.9 Hz and 50.1 Hz).