Improving power quality at a Gqeberha supermarket
A Rubicon power quality project replaced a faulty power factor correction system at a supermarket with a 100 kVAr Delta SVG. Testing during normal supermarket operation showed improved power factor, lower harmonic current and improved balance between phase currents.
Electrical network problems can go unnoticed until equipment fails, operations are interrupted or costs rise. Poor power factor, harmonic distortion and rapidly changing loads can place unnecessary stress on electrical infrastructure. Understanding these conditions is an important step in reducing operational risk.
Rubicon assesses electrical networks under real operating conditions and recommends solutions based on measured site data. Monitoring after installation helps verify improvements and guide further action.
Replacing a faulty power factor correction system
At a supermarket in Gqeberha, the existing contactor-based power factor correction (PFC) system was faulty and needed to be replaced. A 100 kVAr Delta Static Var Generator (SVG) was installed to provide dynamic reactive power compensation, harmonic current compensation and phase current balancing.
SineTamer devices were also installed to provide additional protection against transient voltage disturbances – brief disturbances in the electrical network’s voltage.
Photo 1. The supermarket’s old contactor-based power factor correction system (left). | Photo 2. The new 100 kVAr Delta SVG installation (right).
Photo 3. An Elspec Pure BB Handheld power quality analyser used for the test.
During normal supermarket operation, the 100 kVAr Delta SVG was intentionally switched off and then back on. The measurement point remained the same throughout. The test compared reactive power, power factor, harmonic current, total demand distortion (TDD) and RMS phase current with the SVG on and off. Apparent power was included as a reference for the site load. This comparison assessed the SVG’s effect under normal operating conditions.
Project details
|
Project or measurement detail |
Recorded information |
|
Site reference |
GQ SUPERMARKET |
|
Measurement point |
Main 800 A breaker |
|
Test date |
1 September 2026 |
|
Equipment commissioned |
Delta 100 kVAr SVG |
|
Power quality analyser |
Elspec Pure BB Handheld |
|
Date issued |
4 September 2026 |
Measured improvements with the SVG in operation
The on/off test showed improvements in power quality at the main 800 A breaker when the SVG was operating. The table below summarises the reported results.
Table 1. Results recorded during the SVG on/off test.
|
Measured parameter |
SVG off |
SVG on |
|
Reactive power |
55 kVAr for much of the period; 124 kVAr peak |
3 kVAr for much of the period; 14 kVAr short peak |
|
Power factor |
0.93–0.97 inductive |
0.99 0.999 inductive |
|
Non-fundamental current |
23–34 A |
3–5 A |
|
Total demand distortion (TDD) |
10–16% |
1–3% |
|
Phase current balance |
Up to 7.8% calculated unbalance at selected OFF timestamp |
Improved phase current balance |
Reduction in reactive power and improved power factor
Power factor indicates how effectively the electrical supply is being used. Dynamic Reactive power compensation helps improve power factor by supplying the reactive power that equipment needs locally.
The 100 kVAr Delta SVG was switched off at approximately 14:59 to assess its effect on reactive power and power factor. With the SVG switched off, the site’s reactive power demand was approximately 55 kVAr for much of the test period, with a peak of approximately 124 kVAr. During this period, the power factor reduced to approximately 0.93–0.97 inductive.
When the SVG was switched back on shortly after 15:04, reactive power reduced to approximately 3 kVAr for much of the period, with only a short peak of approximately 14 kVAr. The power factor returned to approximately 1.00.
Apparent power provides a reference for the site load during the test. The comparison shows that the SVG was compensating for the site’s reactive power demand and maintaining power factor close to 1. Unity
Figure 1. Reactive power, power factor and apparent power with the Delta SVG on, off and on again.
Lower harmonic current and distortion
Non-fundamental current is the part of the current outside the fundamental supply frequency. TDD expresses harmonic current distortion relative to the electrical system’s maximum demand current. Lower readings indicate less measured current distortion.
With the SVG operating, non-fundamental current was approximately 3–5 A per phase, with TDD generally around 1–3%. When the SVG was switched off, non-fundamental current increased to approximately 23 A on phases 1 and 2 and 32–34 A on phase 3. TDD increased to approximately 10–11% on phases 1 and 2 and 15–16% on phase 3.
When the SVG was switched back on shortly after 15:04, non-fundamental current fell to approximately 3–5 A, while TDD fell to 1–3%. The apparent-power trace provides a reference for the site load and shows that this reduction was not simply due to the site load being removed.
The results show that the SVG was providing harmonic current compensation and substantially reducing measured non-fundamental current and TDD at the main 800 A breaker.
Figure 2. Non-fundamental current, total demand distortion (TDD) and apparent power during the SVG on/off test.
Better balance between phase currents
The test also compared RMS phase currents to assess how evenly current was distributed across the three phases. With the SVG operating, the currents generally followed each other more closely. A larger difference between the phases became visible when the SVG was switched off.
At approximately 15:03, while the SVG was switched off, the measured phase currents were approximately 237 A, 206 A and 217 A. The average phase current was approximately 220 A, with a maximum deviation of approximately 17 A, giving a calculated phase-current unbalance of approximately 7.8%.
When the SVG was switched back on shortly after 15:04, the phase currents moved closer together again. This shows that the SVG was assisting with phase current balancing. Apparent power provides a reference for the site load during the test.
Figure 3. RMS phase currents, non-fundamental current and apparent power during the SVG on/off test.
What the results mean for the supermarket
For the supermarket, the test provided measured evidence that the SVG was performing all three functions assessed: compensating for reactive power, reducing harmonic current and improving phase current balance. These improvements support the broader goal of reducing electrical stress and protecting equipment from power quality problems.
Reviewing performance over time
A follow-up power quality assessment is recommended during the fourth quarter of 2026. This would review the system’s performance over a longer period and under different site loading conditions.
Contact Rubicon Industrial Automation for a power quality assessment to identify risks and recommend the right solution based on measured site data. Visit industrial.rubicon.tech or call +27 80 782 4266.
Disclaimer
While every effort has been made to ensure the accuracy and reliability of the information presented herein, the Rubicon Group makes no representations or warranties, express or implied, regarding the completeness, accuracy, or suitability of the information. Users of this report are encouraged to verify and evaluate the information independently. Neither Rubicon Group, nor any of its employees, officers, or agents of the Rubicon Group of companies, including the authors hereof, shall be liable for any errors, omissions, or damages resulting from the use of this report and the information contained herein. Furthermore, the information provided herein is based on the data available at the time site investigations were concluded and may not reflect the latest developments in the field and/or the investigated site.