Solving Power Quality Penalties in PV Sites: A Case Study

Many iron welding factories now use solar power to save money. However, adding photovoltaic (PV) systems can create new electrical problems. One site faced huge monthly fines because their power factor dropped. This article explains how we solved this issue using advanced technology.

The Challenge of Low Power Factor

The site has five main transformers. Transformers T1 through T4 power the factory loads. Transformer T5 is for the PV power generation. Last year, the site paid $4,100 in penalties. After adding more PV equipment, the fines grew. Recent monthly penalties reached between $2,800 and $4,100.

The factory uses capacitor cabinets for reactive power. These cabinets work well for standard loads. But PV systems change how the grid sees power. Most factory demand is now met by solar energy. This reduces the active power drawn from the grid.

The utility meter only tracks forward active power. It does not track reverse power well. This makes the metered power factor look much lower than it really is. Also, old capacitor banks react too slowly to solar changes.

Site Test Data Analysis

We tested the low-voltage side of all five transformers. We found several issues during our site visit.  Below is the data from our initial tests.

Our tests showed high harmonic current distortion. The 5th and 7th harmonics were above the safe limits. This happened because the capacitor cabinets caused resonance. Resonance can damage equipment and cause heat.

The Recommended SVG Solution

To fix the penalties, the site needed precise control. We recommended a Static Var Generator (SVG). ¹² An SVG uses modern IGBT technology. It generates current to cancel out reactive power instantly.

The current reactive power need is about 200 kvar. We suggested a 400 kvar SVG for the T1 transformer. This allows for future growth in the park.

The SVG samples data from the high-voltage side. It then compensates on the low-voltage side in real-time. ¹⁶ This method is much faster than using old capacitors.

SVG Features and Performance

The SVG offers many benefits for industrial sites. It responds in less than 5 milliseconds. It can handle both inductive and capacitive power.

The SVG is very efficient and precise. It keeps the power factor above 0.99. It also filters out the harmful harmonics we found.

Real-World Compensation Results

We tested the site for three days after the install. The results were excellent. The power factor stayed near 1.00.

Reactive power dropped from 200 kvar to 20 kvar. The site no longer pays expensive penalty fees. The electrical system is now stable and safe.

Using an SVG is the best way to manage solar power sites. It protects your equipment from resonance. It also ensures you never pay power factor fines again.