When located in remote locations, transformers and other power equipment are vulnerable to harmonics and noise caused by insufficient damping and exposure to ambient electrical currents. If these problems are not addressed, they can cause component failure and serious damage to the local power supply. When Fairfields Control Systems, a systems integrator specializing in unique control and automation systems, experienced failures at two recently upgraded sites, it turned power quality specialist CP Automation for a solution.

Fairfields Control Systems provides turnkey Mechanical, Electrical, Instrumentation, Control and Automation (MEICA) solutions for a range of industries including flood protection and factory automation.

As an Environment Agency (EA) contractor, Fairfields recently upgraded the borehole pumps at seven of its UK groundwater sites with variable speed drives that are powered by transformers. Each transformer helped power a pumping station that was used to relieve low river flows.

Transformers and harmonics

Transformers are common in many industrial settings, stepping down conventional power circuits to operate low voltage devices. They can also be used in remote locations to transfer power to more isolated sites. When located in more remote outdoor locations, transformers are usually smaller and mounted high on concrete or wooden posts or platforms.

Fairfields had recently upgraded the well pumps at seven of EA’s sites. But soon after the upgrade, the surge protective devices (SPDs), which limit transient voltages by diverting or limiting the surge current, began to fail on two of them. It was clear that there were unusual power supply characteristics and that harmonic distortion levels were too high.

Voltage distortion is any deviation from the nominal sinusoidal shape of the AC mains voltage. It is caused when current harmonics increase the voltage and electric currents in a circuit and can overheat the power system, destabilize the voltage and damage the equipment. It was also important that Fairfields resolved the issue to remain compliant with Engineering Recommendation G5/4, which sets out planning levels for harmonic voltage distortion.

Turning a corner

Fairfields already had a relationship with CP Automation as the company had carried out various studies and consultancy on various projects in the past.

“CP Automation’s power quality expertise is critical to protecting our systems,” explained Peter McMorrow, Engineering Director at Fairfields Control Systems. “The groundwater project was different. Although we can often anticipate problems with noise and power quality, in this case we already had problems. Once identified, our priorities were to determine the source of the unusual supply and its characteristics. Our plan was to retrofit the equipment to mitigate the effects.

“The total harmonic distortion (THDi) was falling outside of its normal value and the voltage was becoming unstable, so long-term damage to the transformer and its components was a real risk,” explained John Mitchell, global business development manager at CP Automation. “After studying the situation, we proposed to replace the damaged SPDs with two SineTamer transient voltage suppressors (TVSS) that protect against overvoltages and transient peaks.’

After proving that the SineTamer could function effectively in high harmonic environments where the original SPDs failed, CP Automation agreed to install the new devices at all EA sites. Meanwhile, he delivered two REVCON Harmonic Filters (RHF) for high harmonic locations to help protect the transformer and other nearby equipment. RHFs prevent harmonic distortion from non-linear loads and sources, reducing THDi to below five percent, which is essential to stay within G5/4 levels.

Stable power supply

Fairfields purchased two RHF-5P two-stage passive filters. In addition to reducing the THDi of variable frequency drives (VFDs) and other non-linear loads, the filters can reach efficiencies of up to 99.5 percent. As a result, power losses are up to 75 percent less than those generated by alternative devices.

Since Fairfields installed the SineTamer and RHFs, the transformers have been operating normally at the EA groundwater sites. By minimizing voltage distortions, technologies provided by CP Automation have prevented problems such as voltage clipping, motor vibration, awkward tripping, electromagnetic interference (EMI) and overheating. In addition, the objects are now compliant with G5/4 standards, as RHFs limit voltage frequency harmonics.

To learn more about how to soften the harmonics by visiting the CP Automation website.

Power quality in remote locations #Engineering #PowerEquipment #PowerQuality #Specialists

Previous article‘I’m afraid of what will happen in the long term’ – Distributor bosses on Covid aftershocks, hiring challenges and ESG roadmaps
Next articleUWB Type-C VBUS Combo Switch