Power Fluctuation Causes and Rectification in Industrial Plants with ACB & Capacitor Banks

Dear all,
  Today In my company 2 times Power faluxation or interruption occurs so, some machines are switch off directly . In this case ACB(air circuit breaker) is not tripped  & we give capacitor banks for protection to plant.  I want to know the technical aspect about power faluxation how it occur , How to rectify these interuptions. 

I presume you are talking about power fluctuations (in this case, changes in the voltage level)?These are often referred to as Brown-Outs (ie less than a black-out).Often ACBs will not trip but these fluctuations can cause problems with many types of equipment - Computers and motors are susceptible to them and any electronic equipment can be affected.I am not sure where capacitor banks come in - these are usually used to correct power factor - but in DC powered equipment more capacitance can hold the power up through short fluctuations and interruptions.Solutions - for small equipment up to maybe 5 KVA or even higher, get a UPS (Uninterruptable Power Supply).  These provide a very steady AC output with battery-backup in case of complete interruptions, but you can only depend on them for short periods - up to an hour or so at the very most.  The more power and the longer time they can supply, the more expensive they will be.For larger loads - say motors in a factory - the easiest solution is to talk to your electricity company, because that is where the problem is coming from.  But in some countries you would not get very far.  I have heard of solutions using a motor driving a flywheel and a generator, but this would be very expensive and again only for a limited time in case of failure.