Uncover the Hidden Issues: Power Quality Audit in Commercial Buildings
Introduction
A power quality audit is a critical assessment that can uncover hidden issues affecting the electrical systems in commercial buildings. Electrical disturbances such as voltage sags, harmonics, and transients can cause problems for sensitive equipment and increase energy costs. A comprehensive power quality audit will identify issues, determine the root causes, and provide solutions to improve reliability and efficiency.
What is a Power Quality Audit?
A power quality audit is a detailed inspection and analysis of a facility’s electrical system. It involves monitoring key parameters such as voltage, current, harmonics, and transients over some time. Data is collected via power quality meters and analysed by engineers to detect anomalies or disturbances.
The audit provides information on the power quality at different points of the electrical system and compares it to established standards. Any deviations from ideal values are flagged and further evaluated to determine the root causes.
Why Perform a Power Quality Audit?
There are several benefits for commercial facilities to undergo periodic power quality audits:
Detect Hidden Issues
Many power quality issues do not cause obvious or immediate problems, so they remain undetected. Issues like harmonics, low power factor, and voltage imbalance can slowly degrade system components or reduce energy efficiency. A power quality audit can uncover these hidden problems.
Prevent Costly Outages
Seemingly minor power quality issues can cause significant financial losses over time. Electric Power Research Institute estimates that voltage sags cost the U.S. industry $119 to $188 billion annually. By identifying power quality problems early, costly downtime and equipment damage can be prevented.
Improve Reliability
A minor but sudden disturbance like a voltage spike or transient can lead to malfunctions or shutdowns of sensitive equipment like servers and industrial machinery. By analysing power quality, preventive measures can be taken to improve reliability and uptime.
Reduce Energy Costs
Power quality issues like harmonics and low power factor force electrical equipment to draw more current to operate correctly. This increases energy consumption and leads to higher utility bills. Correcting power quality can reduce current draw and energy costs.
The Power Quality Audit Process
A comprehensive power quality audit consists of the following key steps:
Initial Site Walkthrough
The electrical system is visually inspected to provide familiarity with the key components and identify any apparent issues. One-line diagrams are reviewed.
Data Collection
Power quality meters are installed to monitor parameters like voltage, harmonics, flicker, and transients. Current levels may also be measured. Data is gathered continuously for usually 1-4 weeks.
Data Analysis
The large amount of recorded data is aggregated and analysed to detect patterns, anomalies, and deviations from standards. The system’s susceptibility to different disturbances is evaluated.
Root Cause Analysis
Abnormal data points are further analysed to determine likely causes. This may require additional targeted measurements and inspections. Common causes include overloaded transformers, large motor/drive loads, and distributed generation sources.
Report & Recommendations
A report summarises the analysis findings, identifies issues and causes, and provides solutions like installing surge suppressors, filters, more prominent conductors, or transformer replacements.
Implementing Audit Recommendations
The solutions recommended in the audit report should be implemented to remediate the identified power quality issues. For extensive facilities, this may be done in phases over time. Even low-cost solutions can provide significant benefits.
Prioritisation
Issues affecting critical systems should take priority. Direct costs like equipment damage should be addressed before indirect costs like energy loss. Solutions with fast paybacks are also good initial targets.
In-House vs. Contractor
Some solutions, like tightening loose connections or replacing fuses, may be implemented by in-house electrical maintenance staff. In contrast, more complex and larger projects, like replacing old or undersized transformers, may require hiring professional electrical contractors. Facilities managers should use discretion on which solutions can be done in-house versus which need outside contractors based on the skillset of their maintenance team.
Follow-Up Measurements
Once solutions are implemented, additional measurements should verify issues have been corrected. Outstanding issues may require revised solutions or further investigation.
Conclusion
A power quality audit provides crucial information on unseen electrical disturbances that reduce reliability and increase commercial facility costs. Uncovering these hidden issues and implementing corrective solutions can substantially benefit building operations and the bottom line. As power systems come under increasing stress, periodic power audit are indispensable for reducing electrical risks.