... creates harmony in power systems.
 
 
 

 

Measurements


Introduction


The harmonic-, transient- and power measurements are normally part of a study performed in order to improve the Power Quality of the plant. In order to present reliable data for the forthcoming analysis, calculations and equipment design, it is necessary that all the measurements described below are performed in a correct manner.That requires, from the engineer responsible for the measurements:

- good knowledge about the instruments
- power systems design and operation
- measurement methods and techniques
- theoretical circuit- and harmonic analysis



Harmonic Measurements

Harmonic measurements are often performed as the first stage of a filter design project.Harmonic measurements are carried out in connection with harmonic related problems such as:

- thermal overloading of power transformers, cables and motors
- capacitor failures
- unjustified protection operations
- malfunctioning of computers and control equipment

There are no distinct rules regarding measurement procedures. It is important to remember that, in order to solve harmonic problems, the measurements must be combined with theoretical systems analysis. The measurements should mainly show the total harmonic generation and the distortion level in the plant. It should be observed that harmonics generated by the converters can be amplified due to resonance between the inductive and capacitive network components. In case there are shunt capacitors or filters in the network, they should be taken in consideration when estimating the actual harmonic generation in the plant.



Transient measurements


Transient measurements are made in connection with equipment failures such as:
-
insulation break down in power transformers, capacitors, cables, motors, electronic circuits - protection tripping of frequency converters or other equipment

The measurement's procedure depends on the type of the measurement to be performed. Measurements of switching transients at energisation of capacitors, transformers motors etc. can normally be carried out very effectively by performing a series of switching operations and recording the results.

The most difficult part of trouble-shooting is to catch randomly appearing transients. In such cases, the system must be monitored during a long period of time using an event-triggered instrument.





HARMONIZER Power Quality Consulting AB has many years experience in Power Quality measurements. We are using the latest instrument technology and well proved monitoring techniques based on applicable standards requirements.