The highest ROI maintenance techniques to maximize the reliability of your utility-scale renewable investment

Preventing unplanned outages, avoiding costly equipment damage, and increasing reliability.

By Don A. Genutis, HALCO, a RESA Power company

These techniques can yield a ROI of over 20x

After performing electrical testing for over 100 utility-scale renewable energy projects throughout the U.S., experts in the field have discovered which practices provide the highest ROI for renewable investments. The following five electrical test techniques represent the most effective practices for preventing outages and increasing production, per dollar spent. These practices cover the majority of common equipment failure modes in the most efficient manner possible. All these techniques can be performed safely without requiring an outage.

(1) Online partial discharge survey

Conducting an online partial discharge survey is highly recommended as the highest ROI technique. Statistics indicate that up to 90 percent of all medium voltage equipment failures occur due to partial discharge activity.

 PARTIAL DISCHARGE is a partial failure of medium voltage or high voltage insulation, which progresses to complete failure over time, resulting in unplanned outages and equipment damage.

The good news is that these partial failures produce signals that can be safely detected through a partial discharge test, while the electrical system remains in service. By connecting sensors around the grounded MV cable concentric shields, electromagnetic signals are recorded to detect and analyze dangerous partial discharge events in the MV terminations, cables, transformer windings, breakers and switchgear assemblies.

(2) Dissolved Gas Analysis (DGA)

Many distribution designs incorporate fluid-filled transformers which are typically filled with FR3, a natural biodegradable fluid. Transformer fluid is used to provide insulation and cooling for the transformer windings fluid condition is critical to transformer health. By taking a small fluid sample and performing laboratory analysis of the gases contained in the sample, abnormal transformer conditions such as arcing, partial discharge, and overheating can be detected. This information can then be used to plan remediation before complete failure occurs.

(3) Infrared thermography

Infrared cameras are very effective in detecting loose connections, which contribute to a high percentage of conductor-related failures. Utilizing infrared technology is an excellent method to detect these issues and enhance reliability. More recently, infrared inspections have become an efficient and safe way to detect solar module problems, such as open strings, damaged modules, and soiling. Conducting module infrared inspections using UAV drones has been particularly effective in ensuring efficient and accurate assessments.

(4) Visual inspections

The value of simplicity should not be overlooked when it comes to maintaining electrical integrity. Visual inspections performed by qualified technicians play a crucial role in identifying various types of defects, ranging from abnormal transformer gauge indications to rodent ingress damage. To ensure the effectiveness of these inspections, it is essential to conduct them regularly. Checklists should be used to record and trend inspection results, providing a comprehensive overview of the equipment’s condition. This practice helps to identify potential issues early on, to allow precious time for planning remediation.

(5) Radio Frequency Interference (RFI) surveys

Radio frequency interference (RFI) surveys provide a unique approach to detecting defects in outdoor substations. Similar to the principles of partial discharge surveys, RFI surveys focus on identifying signals caused by insulation defects. These defects create signals that are emitted into the air, much like a small radio transmitter. Antenna-based instruments are used to detect and analyze RFI signals associated with various equipment defects, including outdoor cable terminations, insulators, instrument transformers, capacitors, circuit breakers, surge arresters, and power transformers. It is recommended to complement RFI surveys with ultrasonic camera instruments for surface defect pinpointing and infrared techniques for detecting thermal problems. By integrating these technologies, substation condition can be accurately determined. 

Conclusion

These five techniques described above provide excellent coverage for the most common types of equipment failure modes and do so safely, and efficiently, are cost-effective, and do not require an outage. Implementing these practices will help avoid unplanned outages, prevent equipment damage, and maximize production at your utility-scale renewable power plant. The return on investment of implementing a comprehensive program incorporating these methods usually exceeds 20X ROI.

Don A. Genutis is a General Manager at HALCO, a RESA Power company. With over 35 years of experience in the power industry, Genutis is a leader in electrical testing and a driving force in advancing no-outage testing techniques. He has authored 50 technical articles and in 2019, he published his book, “Partial Discharge & Other No-Outage Testing Methods,” which summarizes his extensive work and findings. In 2023, HALCO Testing Services joined RESA Power. www.resapower.com

Q4 2023