First, the series inductors will be replaced by their equivalent transmission line sections, and then the shunt capacitors will be replaced by capacitive frequency selective surfaces.
12.
In the left-hand figure, the Za arm has a shunt capacitor, C a, and the Zb arm has a series capacitor, C b.
13.
The shunt capacitors are usually connected directly to the grid voltage but in some cases may be connected to a lower voltage via a tertiary winding on the converter transformer.
14.
The most commonly seen of these is a low-pass ?-filter consisting of a reservoir capacitor followed by a series choke followed by a further shunt capacitor.
15.
One-dimensional line gratings can be modeled as shunt inductors ( for polarization parallel to the lines ) or shunt capacitors ( for polarization perpendicular to the lines ).
16.
Voltage-source converters, on the other hand, can either produce or consume reactive power on demand, with the result that usually no separate shunt capacitors are needed ( other than those required purely for filtering ).
17.
The idea we'll follow is that the shunt capacitors will eventually be replaced by sub-resonant ( capacitive ) patch-type FSS sheets and the series inductors will be replaced by air spacers between the 5 FSS layers.
18.
Since the reactive power consumed depends on the active power being transmitted, the shunt capacitors usually need to be subdivided into a number of switchable banks ( typically 4 per converter ) in order to prevent a surplus of reactive power being generated at low transmitted power.
19.
Although at HVDC converter stations connected directly to power stations some of the reactive power may be provided by the generators themselves, in most cases the reactive power consumed by the converter must be provided by banks of shunt capacitors connected at the AC terminals of the converter.
20.
Fitting a shunt capacitor to a real FSS is done by repeated running of a first principles code to match the reflection response of the shunt capacitor with the reflection from a capacitive FSS . Patch-type FSS below resonance will produce a capacitive shunt admittance equivalent circuit, with closer packing of elements in the FSS sheet yielding higher shunt capacitance values in the equivalent circuit.
