Understanding Partial Discharge in Rotating Machines
The Causes of Partial Discharge in Rotating Machines
In rotating machines, PD can arise from various sources, including:
- Void Formation in Insulation: Manufacturing inconsistencies, thermal expansion, or mechanical stresses can create voids within stator winding insulation. These voids become sites of concentrated electric fields, triggering PD activity.
- Surface Contamination and Tracking: Dust, moisture, or other contaminants can create conductive paths on insulation surfaces, leading to surface discharges that accelerate material degradation.
- Ageing and Thermal Stress: Continuous exposure to operational heat cycles weakens insulation over time, reducing its dielectric strength and increasing susceptibility to PD.
- Poor Installation or Repairs: Improper installation of windings, insulation components, or repairs can introduce insulation defects that foster PD activity.
The Impact of Partial Discharge
Undetected PD poses significant risks to machine performance and asset reliability, including:
- Gradual Insulation Breakdown: Persistent PD weakens insulation barriers, leading to progressive deterioration and eventual failure.
- Thermal Damage: The localized heating effect of PD can exacerbate insulation stress, accelerating material breakdown.
- Electromagnetic Interference: PD generates electromagnetic emissions that can disrupt control systems and other sensitive electronic equipment.
Monitra’s Approach to Partial Discharge Monitoring
At Monitra, we specialise in advanced condition monitoring solutions designed to detect, analyse, and mitigate PD risks in rotating machines. Our approach integrates:
- On-line Partial Discharge Monitoring System: Kronos by Monitra enables continuous assessment without requiring machine shutdowns. Using high-frequency current transformers (HFCTs) and coupling capacitors, our systems capture and analyse PD signals, providing actionable insights into insulation health.
- On-line Partial Discharge Testing: Monitra provide PD testing to ensure early fault detection and minimise downtime. Our PD testing capabilities are powered by the Kronos Spot Tester, a powerful tool for accurately diagnosing insulation condition and identifying developing faults.
- Offline Partial Discharge Testing: We offer offline PD testing as part of routine maintenance or commissioning. This helps detect latent defects before machines return to service. Read more:
- Partial Discharge Training: Monitra offers expert-led training programmes to help operators and maintenance teams understand PD phenomena, improve detection capabilities, and optimise maintenance strategies.
- Machine Learning-Driven Diagnostics: Leveraging advanced machine learning algorithms, Monitra’s PD analysis platform can differentiate between benign noise and genuine discharge activity, reducing false alarms and improving predictive accuracy.
- Expert Consultation and Custom Solutions: Our global team of specialists provides tailored recommendations based on PD test results, ensuring that mitigation strategies align with asset-specific operational demands.
Implementing a proactive PD monitoring strategy helps reduce unplanned outages, extend asset life, and enhance overall system reliability. With Monitra’s cutting-edge technology and expertise, high-voltage asset owners can transition from reactive maintenance to predictive condition-based monitoring, maximising uptime and operational efficiency.
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