What is the degree of effect of bad equality power on electrical equipment, and how can the maintenance help to increase the efficiency of them?

Once ABB  ACS  800 LT Drives having DC-Bus-Voltage- High and some of the Mobile- Laptop charger got  Brust, 1 Ash Handling PLC got damaged etc etc .....LT Single Phase Voltage Reaches 265 Volt AC. All this thing happen when OUR TG is running in Low Power Factor say 0.6 in low Load condition & TG is running in Island condition. So bad power quality is due to Low Power factor & some times due to High %Thd in our system or any thing else.

Operation / Maintenance Engineer duty in those condition is to Reduce Incoming TG Voltage, say normally we maintain our Tg voltage in Between 11 KV- 11.1 KV, that time we have to maintain TG voltage 10.8-10.9 KV , so to reduce LT Voltage.

In cade of harmonics is high, we have to install Harmonics Flter to improve Power Quality...

In Electrical maintenance,Periodical maintenance is to be taken at schdule time,Maintainning history cards of each and every equipment with it's complete specification in the name plate ,and logging the details with out fail.In power concern stabalised voltage with out power intrruption is to be taken.The people those who are working must have the knowledge of process,then only will taken correct preventure measures to take correct action.

To maintain an electrical equipment must have self decipline and lists of an equipment must identified.