Compound-type Exciter analysis

1. Apr 20, 2006

n1mr0d

Hi, i am currently analysing a static exciter for a genset. It appears to be of the compound-type, a power potential transformer and a power current transformer provides the field power of the generator. The current transformer kick in when there is are large loads like ground faults and transformer inrush currents.

Without regulation the exciter provides about 10% higher voltage, which is trimmed (shunted) through the red path when SCR3 is phase angle fired.

This brings me to coil L2, which i guess is to create a higher voltage because it circumvents L1 and T1. I don't know the inductance values of the coils. I don't think it is a coincidence this is the same phase that is also used for regulation purposes.

The last thing that boggles me is the current transformer. It has the following nameplate (located on the back!):

H 16-1-1
16-1-1
Z 2-1
2-1 Y3
(Y=pri/Z,H=sec)

Which actually makes some sense, because it is a multi-tapped transformer, specially tuned to the generator.

From how wires are connected we can derive the following winding configuration (viewed from the side of the transformer):

HZ Y ZH
18 3 3 3 18

The Z and H windings are put is series in a special way, which seems to derive the max amplitude.

I would like to derive the pri/sec phase and amplitude characteristics of the voltage and current (cos phi=0.8). Is it possible to derive the characteristics from the diagram, assuming it is a ideal transformer?

Can someone tell me more about how this circuit works, especially the phasor relationship between the PPT and PCT.

http://members.home.nl/damellema/CS4.PNG"

http://members.home.nl/damellema/PCT.JPG"

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Last edited by a moderator: Apr 22, 2017 at 9:41 AM