Talk:Electric power quality

nominal voltage
What is an example of nominal voltage? Does this mean the voltage nominated appropriate to the situation? Sholto Maud 12:27, 2 June 2007 (UTC)

It's nominal as in named. Examples are 120, 240, 480, 600 and 115, 230, 460, 575. They are voltages that are the intended values for various equipment, as shown on the equipment's label or nameplate for instance. —Preceding unsigned comment added by Ronpeters (talk • contribs) 02:46, 23 October 2007 (UTC)

Suggest merge
Power quality compression algorithm, once you remove the "et als" and boil it down to its actual content, doesn't say much about its subject and could usefully be merged here; it hardly seems a topic for a free-standing article in a general-purpose encyclopedia. --Wtshymanski (talk) 20:38, 7 March 2013 (UTC)

recent edits (2016)
I rewrote the first paragraph of the article because the first sentence was both grammatically unclear and used a technical quote. Clearer explanations and simplified concepts are more appropriate for an introduction to the topic. I split the introduction into another category called Power Quality Deviations to make navigating easier, and reorganized the bullet points into sub sections for clarity- mimicking the concept of power quality as a function of voltage, frequency and waveform. Added an explanation for harmonics to better illustrate how waveform effects power quality. — Preceding unsigned comment added by Maiacossey (talk • contribs) 08:04, 6 December 2016 (UTC)

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Active and reactive power, or, phase differences.
I hesitate to adjust the lead paragraph, but there is no mention of the desire that a good power supply works with only a small difference between the phase of the current and voltage in the power it supplies to its load. In AC systems this is so important that causes of discrepancy are sought out and suppressed! In a transmission line the power delivered is the product of the RMS voltages and currents in the usual manner, times the cosine of the phase difference. If this difference is small (less than ten degrees, say) as it usually is then Watts = V*I, but, to maintain the capacity of a transmission line when there is a larger phase difference, the voltage cannot be raised (because the insulation might break down) so the current must be raised. But the resistive loss is given by the resistance times the square of the current and so the loss soon becomes too great, if not damaging to the transmission line - though power lines in New Zealand have been briefly overloaded so as to melt off ice... Generators thus supply not just active power but also "reactive power" (or consume: sign conventions!) and the modern appearance of electronic waveform generation (especially supplied by large DC batteries) not only supplies voltage support (and frequency stabilisation) when a system's normal generation is being overloaded and the voltage and frequency is falling, but also can supply reactive power. Or the reverse if the system load falls faster than normal generators can back off. NickyMcLean (talk) 10:16, 1 May 2019 (UTC)
 * This is covered under power factor and presents rather distinct AC-specific problem. The topic of “electric power quality” is not ohmic losses of power in transmission lines. Incnis Mrsi (talk) 12:03, 1 May 2019 (UTC)

Should this article also cover DC power quality?
There's a fair amount of information about analogous quality attributes of DC power systems (e.g. voltage sag, ripple), especially in the context of computer power supplies. I'm not sure whether the term "power quality" is ever used to describe AC though. Should it be added here? If not, we should still link to where it's covered somewhere else. 2620:15C:7C:200:8593:DB48:3FD2:2404 (talk) 23:42, 4 August 2022 (UTC)