Capacitor Banks

hello

i have several questions about the capacitor banks !
1- how does the capacitor bank causes voltage rise ?
2- how does it make the power more efficient since it only eliminates the ( KVar ) effect ?
3- when do we use the ( shunt ,series , filter ) capacitor banks ?

thanks a lot ,,

In a related question: In a distribution substation why must a capacitor bank be taken offline first before de-energizing the substation (opening the distribution feeder breakers and opening the high side switch to de-energize he substation transformer).

Shunt capacitor are used mainly for Power factor correction. The optimization and improvement of power factor correction (as close to PF=1) has many benefits. Benefits such as transformer line losses, voltage profile improvement, reduction of maximum demand, and improved power quality.

In distribution systems, as load gets further from the source (substation), voltage at the load end typically goes down due to the lack of reactive power. Capacitor banks can be installed to inject VARS thereby supporting the voltage at the end of the line.


Series capacitors are connected in series in the circuit - thereby, carries the full line current. The voltage across the shunt capacitor remains constant, and the
drop across the series capacitor changes with load.


Since the series capictor reacts to load, makes it valuable in transmission and distribution line compensation. Think of the series capacitor as a negative reactance with a transmission line.

The voltage rise across the capacitor is a function of circuit current and acts like a voltage regulator.

The negative voltage drop across the series capacitor opposes the voltage drop due to the inductive reactance. Such effects are very valuable in radial feeders to reduce voltage drop and flicker effects. In the tie lines, the power transfer capability is significantly increased if the series compensation is applied.


Addition of significant shunt capacitors at the motor terminal may lead to overvoltages due to selfexcitation
when the motors are switched off with capacitors.


These shunt capacitor banks are switched in and out as needed. The switching operations include energizing, de-energizing, fault clearing, backup fault clearing, and reclosing. Sometimes a restrike occurs due to excessive voltage across the circuit breaker blades. Further, in the capacitor banks there may be bus fault conditions
responsible for significant outrush current.

checkout "Power System Capacitors" by Ramasamy Natarajan

Also checkout http://generalpac.com
Balanced 3 Phase Systems: http://gpac.link/1xuAErt
Wye Wye Transformer Connection: http://gpac.link/1usweRt
Symmetrical Components: http://gpac.link/175IP7B