kapp_regulation_diagram

Stan Zurek, Kapp regulation diagram, Encyclopedia-Magnetica.com, {accessed 2020-02-27} |

reviewed by Jeanete Leicht, 2014-02-01 |

**Kapp regulation diagram** (or in short **Kapp diagram**) - a graphical method of determining the voltage regulation in a transformer caused by changes in load and power factor.^{2)}

The output voltage of a mains power transformer when loaded reduces for inductive load (power factor lagging) and increases for capacitive load (power factor is leading).

The Kapp diagram is helpful in finding the voltage reduction or increase (voltage regulation). The main disadvantage is that the voltage regulation phasors are much smaller than the radii of the main circles, so the diagram has to be drawn on a very large scale to get sufficiently accurate results.^{3)}

In order to create the diagram it is necessary to know the equivalent reactance * X_{02}* and resistance

The following algorithm should be used:

- Draw
representing the phase of the secondary current at an angle**OX**to**Φ**_{2}such that cos(**OL**) is the power factor of the load**Φ**_{2} - Draw phasor
(where**LM**is the voltage drop on resistance referred to the secondary side) parallel to**I**_{2}·R_{02}, and then**OX**(where**MN**is the voltage drop on reactance referred to the secondary side). The resulting**I**_{2}·X_{02}is the total voltage drop.**NL** - Transfer the impedance triangle
to**NLM**which gives**OO'P**=**O'L**=**ON**. Therefore, for a given secondary current the locus of_{0}V_{2}is the circle with centre**N**and radius**O**, while the locus of_{0}V_{2}has the same radius but with the centre**L****O'** - To find the voltage drop on full load at any power factor the radius
(joining the three points**OS**) should be drawn at at angle**OQS**to**Φ**. If the impedance triangle is drawn at the position**OX**then**UQT**=**OU**. The length of**OS**represents the sought-after voltage drop.**QS**

kapp_regulation_diagram.txt · Last modified: 2019/06/03 18:29 (external edit)