Improving reliability and providing superior customer experience at a cinema in Egypt

Challenges in the customer’s cinema

The use of heat, ventilation, and air conditioning (HVAC) systems has increased in the last decade to efficiently control the temperature for example in hospitals, shopping malls, and offices. Variable Frequency Drives (VFD) are more and more being used to increase the efficiency of various HVAC-system components such as compressors, chillers, fans, and pumps. However, VFDs are sources of harmonic distortions, especially high in 5th, 7th, and 11th-order harmonic currents.

VOX cinema experienced reliability and other issues commonly associated with harmonic distortions. Merus Power’s authorized local partner in Egypt, ETA Electric, was approached by the project’s consultant to analyze the prevailing power quality issues and solve them. A power quality audit performed by ETA Electric revealed high current harmonic distortions on the transformer feeding the cinema with THDi% close to 18%.

Our Merus^® Solution

Based on the power quality audit, the required harmonic compensation capacity was calculated for the transformer feeding the VOX cinema. Along with VFDs, the cinema also had single-phase LED lighting loads which predominantly create zero-sequence tripled harmonics (odd multiples of 3rd harmonics). Thus, a 3-phase 4-wire active harmonic filtering solution was chosen to cancel harmonics in three phases and in neutral.

Merus Power delivered a Merus^® Active Harmonic Filter module, whereas the integration of the module into the cabinet, and the installation in a closed-loop connection at the site was taken care of by ETA Electric according to Merus Power’s guidelines. Commissioning of the solution was carried out by Merus Power as per the agreement.

Results after installation

The main individual harmonics at the cinema were the 3rd, 5th, 7th, 9th, 11th, and 13th-order harmonics. From Merus^® Active Harmonic Filter, a selective harmonic filtering configuration was chosen, and harmonic filtering solution was commissioned. The total current harmonic distortions dropped from around 18% to below 3%. Tripled harmonics that were overloading the neutral wire were now successfully mitigated, improving the safety of the cinema.