Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 82454925, Entry date: 12/02/2013

7KM42 - Setting Reactive Power Measuring Type by powerconfig

  • Entry
  • Associated product(s)


What is the difference between Qn, Q1 und Qtot which can be set as “Reactive Power Measuring Type” in a PAC4200 by Powerconfig?


If all existing power values over the fundamental of voltage (= U1; Sinusoidal with mains frequency) are shown graphical, it results in a general tetrahedron:

See also the following FAQ:

The adjustable options on Powerconfig Q1 and Qtot meet the reactive power identifiers shown in the tetrahedron:

Q1        =          Displacement reactive power over the fundamental U1
Qtot       =          Total reactive power

It is not possible toshow Qn in the graphic above and is explained as follows:

Qn = Shift reactive power over fundamental U1 + harmonics U. Because of, in practice, most commonly high fundamental frequency content of the voltage results: Qn ≈ Q1

Q1 is usually to use as a preferred setting, particularly as their compensation systems to obtain cos φ, which is directly related to this.

Note for the devices PAC3100 and PAC3200:
Output for reactive power is always Qn.

Mathematical context:


FAQ_PAC4200_QX_EN.PDF (92 KB) ( 92 KB )  

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit
Rate entry
no rating
Requests and feedback
What do you want to do?
Note: The feedback always relates to the current entry / product. Your message will be forwarded to our technical editors working in the Online Support. In a few days, you will receive a response if your feedback requires one. If we have no further questions, you will not hear from us.