With 'system.dynType = SteadyState' transients are suppressed and only slow dynamics, imposed by the source-voltage is resolved.
This quasi-stationary approximation corresponds to an infinitely fast response of the system.
See for example:
meter.p[1] active power in pu, changing from 0.5 (1000 MW) to 0.25 (500 MW) meter.p[2] reactive power in pu, from 0.25 (500 MW) to 0.125 (250 MW)and other meter-signals.