*5.1. Synthetic Subset*

The original aspects of the Synthetic subset include multiple concurrent loads of distinct classes, with precise turn-ON and turn-OFF control and annotations of these events with an accuracy better than 5 ms. These annotations (labels) can later be used to validate event detection, transient feature extraction, and load classification methods.

The synthetic subset is composed of 1664 acquisition for single, double, threefold, and eight-fold concurrent loads. For every load or load combinations, acquisitions are made for 16 distinct turn-on trigger angles.

In Figure 12a, the acquisition of an incandescent lamp with a turn-on trigger angle of 90 degrees is shown, while Figure 12b,c present a detailed (zoomed-in) view of the turn-ON and turn-OFF events, respectively. The high inrush current is due to the variation of the filament resistance of the lamp, as its temperature rises. The inrush current is also dependent on the turn-on trigger angle. This unique transient response may be beneficial to the detection as well as the classification methods. In these figures, the up-arrow indicates a turn-ON event while the down-arrow indicates a turn-OFF event.

**Figure 12.** Jig acquisition of a single load: incandescent lamp—trigger angle of 90 degrees. (**a**) Complete acquisition—AC mains voltage and current. (**b**) Turn-ON event. (**c**) Turn-OFF event.

A single load acquisition of a laptop power supply is presented in Figure 13a, for a turn-on trigger angle of 45 degrees. A detail of the turn-ON and turn-OFF events are presented in Figure 13b,c. Typically a power supply first stage consists of a diode rectifier followed by a capacitor. The inrush current depends on the capacitance and the turn-on trigger angle and is very high compared to the steady-state peak current. This transient response is very rich in detecting an event and classify the load. The steady-state low power may be challenging to detect and classification steady-state based methods.

**Figure 13.** Jig acquisition of a single load: laptop power supply—trigger angle of 45 degrees. (**a**) Complete acquisition—AC mains voltage and current. (**b**) Turn-ON event. (**c**) Turn-OFF event.

An example of a double load acquisition is presented in Figure 14. An oil heater (520 W) is turned-on (trigger angle of 135 degrees), and then a LED lamp (6 W) is turned on, also at trigger angle of 135 degrees. Later, the heater is turned off, and finally, the lamp is turned off. This is an interesting combination of linear and non-linear loads of significantly different power levels. Details of the turn-ON and turn-OFF events are presented in Figure 15a–d. As the oil heater has a higher power, the turn-ON event of the LED lamp may be challenging to detect, as Figure 15b shows, likewise, the turn-OFF event of the LED lamp, as shows Figure 15d.

**Figure 14.** Jig acquisition of two loads: oil heater and LED lamp—trigger angle of 135 degrees.

**Figure 15.** Jig acquisition of two loads: oil heater and LED lamp—trigger angle of 135 degrees. (**a**) Turn-ON event section A: heater turned on. (**b**) Turn-ON event section B: LED lamp turned on. (**c**) Turn-OFF event section C: heater turned off. (**d**) Turn-OFF event section D: LED lamp turned off.

A three loads combination composed of a hairdryer, a LED lamp, and a drill is presented in Figure 16, with a turn-on trigger angle of 225 degrees. The hairdryer, at the low power level setting, has a half-wave diode rectifier, hence, an asymmetrical load. The drill high inrush current may also be observed.

**Figure 16.** Jig acquisition of three loads: hairdryer at low power level, LED lamp, and drill—trigger angle of 225 degrees. AC mains voltage and current.

Finally, Figure 17 shows an example of eight loads combination: a LED lamp, a laptop power supply, a microwave, a cell phone charger, a soldering station, an incandescent lamp, an oil heater, and a smoke extractor with turn-on events triggered at 270 degrees. The combination of eight loads with different power levels, linear and non-linear characteristics, is important to evaluate detection and classification methods.

**Figure 17.** Jig acquisition of eight loads: LED lamp, laptop power supply, microwave, cell phone charger, soldering station, incandescent lamp, oil heater, smoke extractor—trigger angle of 270 degrees. AC mains voltage and current.
