SVC Capacitor Sizing Calculation

Your SVC is likely to be used in parallel with a load that has variable reactive power consumption requirement such as EAF.

Alternatively it is needed for voltage stabilization in a grid network.

You need to specify the application and the design varies based on the application.

in our case SVC is used for EAF(200MVA) and LF(40MVA) and PCC is the 400KV bus. So how can i calculate the capacitor size?

The extent of reactive power variation in EAF, LF needs to be compensated by the TCR in parallel with the Fixed capacitors of the filters. So the first step is to determine this total reactive power compensation needed.

Second step is to find out the characteristic hramonic currents injected from the combination of both the SVC and the EAF, LF. This will give you the number of tuned harmonic filters needed and high pass filter needed. Note that uncharacteristic harmonic currents may also be present in EAF and LF and the design data for the same must be obtained by the supplier of EAF and LF.

Third step is to work out combinations of Fixed capacitors in series with the tuning reactors for all the filters identified, such that at fundamental frequency this series combination provides the maximum compensation needed for the combination of EAF and LF, while providing a low impedance path to the harmonic current for which it is tuned.

Note that several combinations of L and C are possible as for each tuning frequency. For any choice of C there is a corresponding choice of L in series that can be tuned for a given harmonic. We may go by standard sizes available or with suitable discrete step sizes before arriving at final configuration.

Finally, we need to perform harmonic analysis - driving point impedance scans of the network- estimate the ratings of the filters considering harmonic currents that may flow into filters for each choice of C and L to arrive at final distribution of compensation among various filters.

Sir, thank you for your useful response. For the system, I calculate total MVAr need to be inject from compensation system and the VTHD and Pst of the system. From the analysis, I select 2nd, 3rd, 5th and 7th harmonic filter banks in the system.

Now, I want to calculate the size of each harmonic filter bank in MVAr and configure the fixed capacitor banks into n-series and m-parallel paths. I collect capacitor bank rating from internet and are given in the form:

Filter Type System Voltage Power Range

Band-pass filters 1 - 500 kV from 3 Mvar

Band-pass filters with detuned reactors 1 - 500 kV from 3 Mvar

High-pass filters 1 - 500 kV from 3 Mvar

C-filter 1 - 500 kV from 3 Mvar

From the above data I can't select the voltage of each capacitor unit and number of series and parallel combination of them. Please guide me in this context.

VTHD - AcronymFinder

TCR - Definition by AcronymFinder

LF - Definition by AcronymFinder

PCC - Definition by AcronymFinder

EAF - Definition by AcronymFinder

SVC - Definition by AcronymFinder