"Power Quality" is a highly abused term.
So, let's start with an easy definition: "Ideal AC Power" has fully sinusoidal voltage and current wave forms, with the wave forms exactly in phase. In three-phase electrical power, this is true for each phase. Moreover, each phase is offset from prior and subsequent phases by 120°.
"Power Quality" confusingly enough refers to the extent to which the electric power circuit observed does not conform to this ideal. So, when people talk about "Power Quality" they actually mean "Power Impurity". Starting from this contradiction, "Power Quality" has several working corollaries:
- Below a threshold, the effects of "non-ideal" power can be ignored.
- When connected to shared power grids these thresholds are either statutory, or generated by customer complaints . They must be addressed or the cause of the power impurity disconnected from the public system.
- If it prevents effective end-user operation, the situation must be addressed in order for them to stay in operation. "Ineffective Operation" includes the inability to start an electric motor, inability to maintain motor torque, or inability to control operating issues like weld quality
- Voltage aspects of "Power Quality" include recurring "sags", "surges", "flicker" and voltage harmonics.
- The current aspects of "Power Quality" primarily includes current harmonic (recurring voltage wave forms different from the ideal power frequency).
- "Power Quality" also covers irregularly occurring events such as lightning (referred to as TVSS) and actual power interruptions (outages).
Here's how Dynamic VAR Compensation lines up against common PQ Issues:
|PQ Issue||Sags||Surges||Flicker||Harmonics||Lightning||Actual Outage|
|VOLTAGE||YES-full solution||YES-full solution||YES-full solution||YES-full solution|
More than one issue can occur at a time.
If your issues include Voltage Fluctuations [or Stability], Voltage Harmonics, or Current Harmonics, then Dynamic VARS are a potential solution.