Capacitor Groups

ALI

Are you trying to correct the power factor of the load on the 11 kv side of the transformer or on the primary side of the transformer? Tell me again what the plan is please.

HI

i have an electricity plan contain of two sides of voltages ,400 k.v grid & 132k.v network , both sides connected together through auto transformers by capacity 250 mva for each one and having 11 k.v coils connected as delta which effect on both sides voltages,sure an auxilliary of power plan and zigzag transformer and earthing resistance and tertiary reactor contain by this low voltage side ,what i need to ask is that i need to choose capacitors groups on 11 k. v side to correct the voltages and mvar for both sides of transformer .thanks

Please note that the primary reason for the Delta connected tertiary in your 400/132kV, 250MVA auto-transformer is for providing a path for the circulation of zero sequence currents, which otherwise would circulate in the transformer main windings thus causing additional heating. Do not use it for PF correction.

what is the type of load, that is:- motors, lights, a combination of the two - and the size of the load in kw?

Please confirm the Voltage ratio of the Auto transformer. It is not advisable to load the Auto transformer Tertiary for PF correction. Even though the it will Correct the PF on in-commer side, it very costly suggestion and it will reduce the out put on secondary side of auto as the capacitor will be construed as a load on the territiary winding. We had very bad experiences when we operated similar connection of 10 mva capacitor on the tertiary delta of 230/110 KV, 100MVA Auto There are successful Schemes of connecting 110 KV/24 MVA Capactor banks on 110 KV Busses of EHV Substations. It is better to adopt such Schemes instead of connecting capacitor to the Teritiary winding of Auto Transformers Good luck