Re: Harmonic filter for better power quality

Home Electrical Engineering Forum General Discussion Harmonic filter for better power quality Re: Harmonic filter for better power quality

M R Srinivas

@guest said:
Hallo jim

we are connected with maintenance of electrical distribution system in india. As u know our std frequency is 50 Hz. systen rated voltage by sypply agency is 11 KV . we installed 250 KVA 11/.433 KV transformer at our site. our Max demand is approx 210 KVA. and type of loads are lighting Mechanical laundry, traing workshops with lathe etc. We are facing problem of low pf. while checking the parameters LT voltage is 460 volts . An old power factor corrector 115 KVAR is in system but not working. How can we increase our Pf to unity or 0.99 lag. are harmonic filters also essential?

Hy Smita,

The Power Factor at the 11kV Grid meter is an ratio of kWH to kVAr….i.e. the PF what is indicated in the electricity bill from Utility department is kWH/kVAH.

So, to improve the power factor close to 0.99, we need to maintain the ratio of kWH to kVAH almost equal, this is possible only by using Automatic Switched Capacitors using microprocessor based PF Regulator.

For a Max Demand of 210kVA, you need about 100kVAr, APFC panel and 1no.5kVAr capacitor unit. The 5kVAr capacitor unit should be connected at the secondary side of transformer permanently to provide reactive power for Transformer magnetizing circuit. But, make sure the capacitor voltage is 480V.

Filter are not necessary.

Hope above answers your question.

M R Srinivas