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Hello everyone,
I am currently designing a low-voltage (230/400 V) power factor correction (PFC) system rated approximately 540 kVAr.
The facility has:
Two transformers 10/0,4kV 1000kVA working in parallel.
Peak active power demand from the grid: approx. 1100 kW
Grid-connected photovoltaic plant: 1000 kW, with 980 kW peak. Connected on LV side of transformers.
So during high irradiance, the net active power imported from the grid can drop significantly and may fluctuate quickly due to cloud movement.
Most of my previous PFC projects were in industrial facilities without (so big) on-site generation. I have limited practical experience with capacitor bank control in systems where PV generation is present and rapidly changing.
My concerns are:
How does high PV penetration typically affect conventional contactor-based capacitor banks (I already know its bad, but how bad)?
Are standard stepped capacitor banks (contactor + capacitor stages) usually sufficient in this type of application?
Under what conditions would a thyristor-switched (dynamic) PFC system become necessary?
What parameters should I analyze to determine whether fast switching is required? I have 15min load profiles, but they seem unsufficient for the analyses because changes in power are much faster. I have measured avg 10min THD-U, it’s 4.8-5.1% when PV is acitve and 2-2.5% when PV is inactive. Because of pretty fine THD, small place for the cabinet I decided not to use expensive and space consuming reactors. I find it cheaper to change capacitors every 3 years than installing expensive reactors.
PV very rearly sends energy back to the utility (tha max P back to utility in the last year was 113kW)
The system will have 11 steps: 20+20+50+50+50+50+50+50+50+50+100 kVAr.
The target power factor is 0.95 (utility billing requirement). The goal is not to reach unity power factor but to avoid penalties while ensuring stable operation and reasonable equipment lifetime.
Any experience-based recommendations or real-world case studies would be greatly appreciated. How to know if one needs fast switching thyristor system?
Thank you in advance.
I am currently designing a low-voltage (230/400 V) power factor correction (PFC) system rated approximately 540 kVAr.
The facility has:
Two transformers 10/0,4kV 1000kVA working in parallel.
Peak active power demand from the grid: approx. 1100 kW
Grid-connected photovoltaic plant: 1000 kW, with 980 kW peak. Connected on LV side of transformers.
So during high irradiance, the net active power imported from the grid can drop significantly and may fluctuate quickly due to cloud movement.
Most of my previous PFC projects were in industrial facilities without (so big) on-site generation. I have limited practical experience with capacitor bank control in systems where PV generation is present and rapidly changing.
My concerns are:
How does high PV penetration typically affect conventional contactor-based capacitor banks (I already know its bad, but how bad)?
Are standard stepped capacitor banks (contactor + capacitor stages) usually sufficient in this type of application?
Under what conditions would a thyristor-switched (dynamic) PFC system become necessary?
What parameters should I analyze to determine whether fast switching is required? I have 15min load profiles, but they seem unsufficient for the analyses because changes in power are much faster. I have measured avg 10min THD-U, it’s 4.8-5.1% when PV is acitve and 2-2.5% when PV is inactive. Because of pretty fine THD, small place for the cabinet I decided not to use expensive and space consuming reactors. I find it cheaper to change capacitors every 3 years than installing expensive reactors.
PV very rearly sends energy back to the utility (tha max P back to utility in the last year was 113kW)
The system will have 11 steps: 20+20+50+50+50+50+50+50+50+50+100 kVAr.
The target power factor is 0.95 (utility billing requirement). The goal is not to reach unity power factor but to avoid penalties while ensuring stable operation and reasonable equipment lifetime.
Any experience-based recommendations or real-world case studies would be greatly appreciated. How to know if one needs fast switching thyristor system?
Thank you in advance.
