Navigating complex power quality challenges in commercial high-rise

Segment background

Commercial buildings include non-residential and non-industrial buildings like hospitals, data centers, shopping malls, airports, hotels, stadiums, exhibition centers, and more. There are various kinds of electronic devices that ensure effective use of space, increase productivity, and guarantee the continuity of operations every day. These are, for example, elevators, escalators, booster pumps, and ventilation fans that are all controlled by Variable Frequency Drives (VFDs). Non-linear loads like VFDs greatly improve our lives but create harmonic distortion and get adversely affected by the poor power quality they generate themselves.

Poor power quality can result in equipment malfunctions, a shortened lifetime of devices, unnecessary downtime, and even data corruption or losses. Operational reliability and availability cannot be guaranteed in the presence of harmonic distortions produced by non-linear loads. To protect sensitive control systems such as fire protection and computers in buildings, harmonic mitigation is a necessity. It is extremely important to ensure that all equipment and devices work as they are supposed to, to protect people from dangerous device malfunctions.

Challenges at the customer’s facility

Our customer, who operates a premier high-rise building complex located in the bustling heart of Melbourne, serves as a prime example. The complex has gone through several expansions over time, complicating its electrical infrastructure. This had a direct and severe impact on the building’s power quality. The electrical loads in this complex consist mainly of VFD-controlled elevators and escalators. These devices are notorious for producing 5th, 7th, and 11th harmonics. The elevators and escalators also have a fast-fluctuating and high reactive power demand. The result was poor power factor and high Total Harmonic Distortion (THD) in the building’s electrical network, leading to operational inefficiencies and safety concerns.

Our Merus^® Solution

After a thorough power quality audit, it was confirmed that a power quality correction equipment was a necessary investment to ensure the correct and safe operation of electrical devices in the building complex. Merus Power’s local partner, Ampcontrol, delivered a Merus^® HPQ – Hybrid Power Quality Compensator to the site. Merus^® HPQ is an economic all-in-one power quality system for combined active harmonic mitigation and power factor correction.

The total solution consists of four 100A Merus^® HPQ modules and four thyristor-controlled 150 kVAr detuned capacitor banks, which are divided between four different substations at the site. Thyristor-controlled capacitor bank steps and dynamic compensation, provided by the Merus^® HPQ module, ensure that even the fast and large reactive power spikes are compensated without over- or under-compensating.

Results after installation

After a successful installation and commissioning phase, significant improvements in the building’s electrical network’s power quality were observed across all four substations. Specifically, the current Total Harmonic Distortion decreased dramatically from 8.5% to a much more manageable 3.1%. Moreover, the three-phase power factor rose impressively from 0.78 to nearly perfect at 0.99, and the average reactive power demand was cut by a notable 16.7%.

The implementation of the Merus^® HPQ system brought about substantial improvements in power quality within the Melbourne high-rise complex. These advancements not only resulted in enhanced operational efficiency and reduced electricity costs but also released additional capacity for future expansions. This case serves to underline the vital role of comprehensive power quality management in commercial buildings.