Partial Discharge Monitoring

Introduction to Partial Discharge Monitoring

As the global demand for electricity continues to rise and infrastructure ages, the need for smarter, more proactive asset management has never been greater. Partial Discharge Monitoring is at the forefront of this transformation, offering utilities and grid operators a powerful tool to detect early signs of electrical insulation failure—before they escalate into costly outages or catastrophic equipment damage.

This technology is not just a diagnostic tool; it’s a strategic investment in the resilience, efficiency, and sustainability of the power grid. By continuously monitoring the health of high-voltage assets, operators can make informed decisions, extend equipment life, and reduce operational risks.

What Is Partial Discharge Monitoring?

Partial discharge (PD) refers to a localized electrical discharge that only partially bridges the insulation between conductors. These discharges are typically microscopic and may seem insignificant at first. However, they are often the first sign of insulation degradation and can lead to complete insulation breakdown if left unaddressed.

Partial discharge monitoring is the process of detecting, recording, and analyzing these discharges in real time or during scheduled maintenance. It provides critical insights into the condition of electrical equipment such as transformers, switchgear, cables, and rotating machines. By identifying PD activity early, utilities can take corrective action before a minor issue becomes a major failure.

How Does Partial Discharge Monitoring Work?

The process begins with the installation of specialized sensors on or near high-voltage equipment. These sensors are designed to detect the high-frequency electromagnetic, acoustic, or electrical signals emitted by partial discharges. Depending on the application, different types of sensors may be used, including:
  • High-Frequency Current Transformers (HFCTs)
  • Ultra-High Frequency (UHF) antenna
  • Acoustic emission sensors
  • Transient Earth Voltage (TEV) sensors
Once the signals are captured, they are transmitted to a data acquisition system where advanced algorithms analyze the patterns, amplitude, and frequency of the discharges. This analysis helps determine the type of discharge, its location, and its severity.

Modern systems often include cloud-based platforms that allow operators to access real-time data, historical trends, and predictive analytics from anywhere. This integration of hardware and software enables a comprehensive view of asset health and supports data-driven maintenance strategies.

Types of Partial Discharge Monitoring

There are several approaches to partial discharge monitoring, each suited to different operational needs and asset criticality:

Online Monitoring

Online PD monitoring is conducted while the equipment is energized and in service. It provides real-time insights and is ideal for critical assets where downtime is not an option. This method allows for continuous surveillance and immediate alerts when abnormal activity is detected.

Offline Testing

Offline PD testing is performed during scheduled maintenance or commissioning. It offers a controlled environment for detailed diagnostics and is often used to validate the condition of new or refurbished equipment before it is energized.

Continuous Monitoring

This approach involves 24/7 monitoring of high-risk or aging infrastructure. It is particularly valuable for assets that are difficult to access or where failure would have significant consequences. Continuous monitoring systems are typically integrated with SCADA or asset management platforms.

Periodic Monitoring

Periodic monitoring involves scheduled assessments using portable equipment. It is a cost-effective solution for lower-risk assets and provides valuable trend data over time. While not as comprehensive as continuous monitoring, it still supports proactive maintenance planning.

Ampacimon’s Solutions for Partial Discharge Monitoring

Ampacimon offers a suite of cutting-edge solutions that help utilities detect, diagnose, and prevent insulation failures before they become costly outages.

Whether you're conducting routine inspections or safeguarding critical assets around the clock, Ampacimon provides the tools to see deeper, act faster, and plan smarter.

Spot Testing with PDSolver & PD Pico, Portable Precision for On-Demand Diagnostics

Ampacimon’s Spot Testing solution is designed for flexibility and speed. It’s the ideal choice for utilities that need to perform targeted inspections, troubleshoot suspected faults, or validate equipment health during commissioning and maintenance.

PDSolver Software: Intelligence at Your Fingertips

PDSolver is a powerful diagnostic platform that transforms raw partial discharge signals into actionable insights. With an intuitive interface and advanced signal processing capabilities, it enables engineers to:
  • Visualize PD activity in real time with phase-resolved patterns (PRPD)
  • Automatically classify discharge types—such as internal, surface, or corona
  • Filter out noise and interference for cleaner diagnostics
  • Generate detailed reports for compliance and asset records
Whether you're in the field or at the office, PDSolver gives you the clarity and confidence to make informed decisions.

PD Pico Sensor: Compact, Capable, and Field-Ready

The PD Pico sensor is a lightweight, high-sensitivity device designed for quick deployment across a variety of asset types. It’s engineered for:
  • Non-intrusive installation on cables, switchgear, and transformers
  • High-frequency detection for accurate PD capture
  • Rugged performance in challenging environments
  • Seamless integration with PDSolver for synchronized analysis
Together, PD Pico and PDSolver form a mobile diagnostic powerhouse—perfect for utilities that value agility without compromising accuracy.

Continuous Monitoring with PD Eye & SmartVisor, Always-On Surveillance for Critical Infrastructure

For assets that demand constant attention—such as aging transformers, remote substations, or high-risk cable networks—Ampacimon’s Continuous Monitoring solution delivers uninterrupted insight and protection.

PD Eye Software: Real-Time Intelligence, Anywhere

PD Eye is a cloud-based analytics platform that continuously collects and interprets PD data from the field. It’s more than a dashboard—it’s a decision-making engine. Key features include:
  • Live monitoring of PD activity across your network
  • Automated alerts for abnormal or escalating discharge patterns
  • Historical trend analysis to support predictive maintenance
  • Integration with SCADA and asset management systems for unified oversight
PD Eye empowers operators to move from reactive firefighting to proactive planning—reducing downtime, extending asset life, and improving grid reliability.

Tailored Solutions for Every Utility

Ampacimon understands that no two grids are alike. That’s why our partial discharge monitoring solutions are designed to be:
  • Scalable: From single substations to nationwide networks
  • Non-intrusive: No need for outages or invasive procedures
  • Interoperable: Compatible with existing systems and workflows
  • User-friendly: Designed for engineers, not just data scientists

Benefits of Partial Discharge Monitoring

The implementation of partial discharge monitoring offers a wide range of benefits that go beyond simple fault detection:
  • Enhanced Reliability: By identifying insulation defects early, operators can prevent unexpected failures and maintain consistent service delivery.
  • Extended Equipment Life: Monitoring reduces stress on assets by enabling timely interventions, thereby extending their operational lifespan.
  • Optimized Maintenance: Shift from reactive to predictive maintenance, reducing emergency repairs and improving resource allocation.
  • Improved Safety: Early detection of faults minimizes the risk of equipment explosions, fires, or other hazardous events.
  • Regulatory Compliance: Meet industry standards and demonstrate a commitment to safety and reliability through documented monitoring practices.

Economic Benefits for Utilities and Grid Operators

From a financial standpoint, the return on investment in partial discharge monitoring is substantial. Avoiding a single transformer failure can save hundreds of thousands of euros in repair costs, lost revenue, and regulatory penalties. When applied across a fleet of assets, the cumulative savings are even more significant.

Predictive maintenance enabled by PD monitoring also reduces the need for emergency interventions, which are typically more expensive and disruptive. Planned maintenance can be scheduled during low-demand periods, minimizing impact on operations and customers.

Additionally, utilities that adopt advanced monitoring technologies often benefit from lower insurance premiums, improved investor confidence, and enhanced public perception. In a competitive and regulated environment, these advantages can provide a critical edge.