Archive for the ‘Power quality’ Category

8/8 – Electrical equipment: know more about Power Harmonics

April 8th, 2010 | 5 Comments | Posted in Power quality
Tags: ,

Basics on

The following figure illustrates the typical waveforms of line current and line voltage for a three-phase variable speed drive.
The line current is distorted as a result of the non linearity of the input rectifier. The voltage distortion is the result of the circulation of the distorted current through the line impedance.
In this example, the Total Harmonic Current Distortion i is equal to 40%, and the Total Harmonic Voltage Distortion u is equal to 4.3%. (See definitions below).

THD - Total Harmonic Distorsion - definition -

(more…)

7/8 – Electrical equipment: harmonic mitigation

February 11th, 2010 | 5 Comments | Posted in Power quality
Tags: , , , , , ,

How to achieve “” ?

Several different solutions are proposed for Harmonic mitigation. The right choice is always dependent on a variety of factors, such as the activity sector, the applicable standards, the power level …. Several solutions are relative to Variable Speed Drives, as this type of represents a large part of the installed power in industrial installations and the most significant current generators.

(more…)

GPS synchronization for power system

January 27th, 2010 | 12 Comments | Posted in Power quality
Tags: , , , , ,

GPS time Synchronization:  starts with precision timing.


Precision timing is required for monitoring and control of electrical power networks where reliability is important.  Circuit breaker control schemes require precise timing to ensure proper operation, and Sequence of Events Recording systems report events with one-millisecond precision to aid diagnostics and troubleshooting.  Typical “” applications include electric utility networks, data centres, hospitals, water treatment plants, refineries, and other process industries.

(more…)

6/8 – Electrical equipment: improve power factor

January 20th, 2010 | 12 Comments | Posted in Power quality
Tags: , , ,

How to improve ?

Power factor has been defined earlier as a function of active and apparent power. For sinusoidal (undistorted) voltage and current, a vector representation is also possible and helpful.
For most electrical loads like motors, the current I is lagging behind the voltage V by an angle phi.
Ia is called the “active” component of the current.
Ir is called the “reactive” component of the current.

Voltage and current vectors

Voltage and current vectors

(more…)

5/8 – Electrical equipment: power harmonics, power factor

December 12th, 2009 | 15 Comments | Posted in Power quality
Tags: , , ,

The benefits of Correction and mitigation

6 Benefits are described here:

  • Reduce electricity bill
  • Reduce power losses
  • Reduce cable size
  • Comply with power harmonic emission limits requested by Utilities
  • Improve process quality
  • Improve business performance
    (more…)
Older Entries

Electrical engineering Community is proudly powered by WordPress
Entries (RSS) and Comments (RSS) and license Creative Commons License

webleads-tracker