Behavior of fast variable loads at the connection to the power supplying source

Power Quality and Electromagnetic Compatibility Aspects at Personal Computers

“…At a first glance, one may be tempted to neglect the influence of a single laptop over the supplying network. But as long as it can send damaging energy through the mains and similar phenomena can occur jointly, special protective measures should be considered [16]. Today, as this sort of equipment is widely used, unless measures to reduce the non-sinusoidal regimes induced by them are taken, the local or medium voltage networks might be affected.…”

“…In this context, it became important to monitor a laptop when supplied from a power grid [16]. The analysis was made during its "idle running" operation, as well as when it was running different programs, by using commercial or original software programs.…”

“…Today, most of us use such equipment, usually with an INTERNET connection. In schools or universities, pupils and students tend to simultaneously run programs on a significant number of machines (sometimes thousands), and this results in many new technical issues related to the need for new supplying networks or to the quality of electric power [16].…”

“…Because we were interested in analyzing this range, we have extended the analyzed frequency range up to a sampling frequency of 80 kHz. This could be achieved only if data were acquired from a single channel by using a DAS, which was specifically designed and manufactured for the applications studied in this paper-Figure 1 [16,22]. The measurement set-up was designed to allow the testing of one or more connected laptops on the phases of a three-phase system (Figure 1a,b).…”

“…The original DAS, along with its supplying sources, sensors for currents and connectors toward laptop(s) can be seen in Figure 1a [16].…”