🏭 Real-World Case: Mysterious Plant Shutdowns

In January 2017, I investigated a mid-sized factory in Gauteng experiencing unexplained shutdowns.
Although lighting remained stable, motor controllers—like VFDs and soft-starters—were malfunctioning due
to unstable single-phase supply. Voltage fluctuations triggered shutdowns, revealing poor power quality
as the root cause.

A similar issue occurred years earlier in the Western Cape. These disturbances affect multiple
industries, including mining, and highlight the need for robust power quality diagnostics.

💸 The Cost of Power Distortions

In the mid-1980s, I recommended a motor-generator set with a flywheel to a client. Though expensive, it
prevented costly downtime caused by repeated power distortions. This solution underscores the financial
impact of poor power quality.

🧪 Recent Incident: Faulty Circuit Breaker Contact

In August 2023, I was asked to analyze loading on a 6.6kV cable feeder. One phase showed near-zero
voltage, causing excessive current on the remaining phases and high neutral current. The culprit: a
faulty circuit breaker contact. Despite reporting the issue, no corrective action was taken—again
revealing the lack of utility responsiveness.

📣 A Call to Action for Utilities

Medium- to large-power users are especially vulnerable to these disturbances. I urge utility companies
to initiate Load Profiling exercises to uncover hidden power quality issues and protect their customers
from costly disruptions.

📽️ Visualizing Harmonics & Voltage Imbalance

On the Agulhas Utilities Corporation Negative Phase Sequencing webpage, I share visuals and videos that
illustrate obliquely type voltages. One video shows a three-phase sinewave with:

• 6% voltage reduction in one phase
• 10% third harmonic distortion across all phases
• Shifting phase crossing points indicating misalignment

While this may seem extreme, I’ve encountered worse. Monitoring and addressing these issues is not
optional—it’s essential.

✅ Conclusion: Awareness & Action

Obliquely type voltages and currents are often overlooked, yet they cause serious disruptions. From
unexplained shutdowns to equipment damage and inflated costs, the consequences are real. Utility
companies and industrial users must act now to monitor, diagnose, and resolve power quality issues.

Ask yourself:

• Is your power supply stable and balanced?
• Are your electricity charges fair and accurate?

Stay informed. Take action. Protect your operations.