Online PD Testing and Monitoring Solutions for Grid Resiliency & Reliability

Overview of BlueBOX Technology: BlueBOX Technology represents an advanced method for assessing the insulation condition of medium and high voltage systems, including transformers, and URD power cables. It operates online, with no outage, offering a robust solution for reliability assessment. Note: BlueBox can be used offline but requires resonance transformer for any overvoltage requirements.

Sensor Range Utilization:

·       Single Sensor Configuration: BlueBox can detect partial discharge in the electrical system, to include terminations, cable, and transformers.

• Dual-Sensor Configuration: BlueBOX employs sensors at both ends of the cable for synchronized signal captures, enabling precise localization of partial discharge (PD) sources.

• Time Delay Measurement: By analyzing the time delay between PD signals received by the two sensors, the system accurately identifies the location of PD sources along the cable.

Noise Removal:

• Wavelet Transform Application: The technology utilizes digital signal processing, specifically the Wavelet transform, to differentiate PD signals from electrical noise. This method identifies characteristic transient events indicative of PD, separating them from the statistical noise background. e.g. Internal PD noise rises quickly and then fades. Electrical noise is repetitive.

• Statistical Component Analysis: By statistically analyzing signal components, BlueBOX can detect PD signals even when obscured by random electrical noise.

• Effective Noise Discrimination: Unlike traditional methods that often attenuate PD signals along with noise, BlueBOX effectively removes background noise to reveal clear PD signals. E.g. noise cancelling headphone, removes the noise to hear clear music sound.

Maintaining PD Signal Integrity:

• High-Frequency Measurement Limitations: Conventional high-frequency (>30MHz) measurement techniques tend to attenuate PD signals, complicating detection over long distances. BlueBOX avoids this issue by focusing on effective noise discrimination rather than high-frequency filtering.

• Source Separation: BlueBOX identifies and separates different PD sources, even in close proximity, by analyzing the PD signal's shape. Parameters such as asymmetry (α, β) and frequency (ω) are used to create a 3D representation of each source.

• Distinct PD Patterns: Post noise removal, BlueBOX generates distinct PD patterns for each source, preventing pattern overlap from different defects and facilitating accurate diagnosis.

IEC Compliance and Benefits:

• IEC 60270 Compliance: BlueBOX Technology adheres to IEC 60270 standards, ensuring that its PD measurement and analysis techniques meet international benchmarks.

• Detailed Diagnostics: The system provides comprehensive diagnostics, including the criticality of each detected PD source, which is essential for timely maintenance and avoiding potential failures.

Advantages of BlueBOX Technology:

1. Enhanced PD Detection: Advanced signal processing techniques allow for the detection of PD signals typically obscured by noise.

2. Precise Localization: Dual-sensor setup and time delay analysis ensure accurate localization of PD sources.

3. Source Differentiation: Unique parameters and 3D representation facilitate the distinction between different types of PDs.

4. IEC Standards Compliance: Ensures reliability and standardization in PD measurement and diagnostics.

5. Proactive Maintenance: Enables proactive maintenance by providing detailed insights into insulation conditions and the criticality of PD sources.

In summary, BlueBOX Technology significantly enhances the effectiveness of PD measurements by eliminating electrical noise and maintaining PD signal integrity, thereby improving the reliability of high voltage electrical installations.

The electric utility industry is dedicated to improving grid resiliency through strategic capital investments. Leveraging advanced technologies like BlueBox partial discharge (PD) testing for aged cable systems and transformers aligns with our clients goals of enhancing reliability, safety, and efficiency. This paper discusses how PD testing can support these objectives by providing early fault detection and targeted maintenance.

Online PD alignment with electric utility customer goals

1. Capital Investment in Infrastructure:

   • Electric utilities have committed to investing billions in modernizing and enhancing infrastructure. Online PD testing can be a crucial part of this modernization by ensuring the reliability of upgraded systems​.

2. Resiliency and Reliability Enhancements:

   • Investments in transmission and distribution hardening. Online PD testing or monitoring can complement grid hardening by providing real-time data on the condition of cable systems and transformers, thereby preventing failures before they occur.

3. Advanced Monitoring and Automation:

   • Electric utilities have invested in automation, monitoring, and communication capabilities to enhance system reliability. Online PD testing aligns with these investments by utilizing advanced AI and noise removal algorithms to monitor insulation health continuously and accurately​.

4. Customer-Centric Improvements:

   • Emphasis on maintaining customer satisfaction through reliable service. Integrating Online PD testing and monitoring clients can reduce outages and improve service reliability, directly benefiting customers and enhancing overall satisfaction​​.

Benefits of Partial Discharge Testing

1. Early Fault Detection:

   • PD testing detects insulation defects early, preventing potential failures and reducing unplanned outages. This proactive approach aligns with CenterPoint Energy’s goal of maintaining reliable service during extreme weather conditions and high demand periods.

2. Targeted Maintenance:

   • Accurate localization of PD sources allows for targeted repairs, optimizing maintenance schedules and reducing downtime. This efficiency is crucial for managing the extensive infrastructure within CenterPoint Energy’s service areas​​.

3. Cost-Effectiveness:

• By preventing major failures and extending the lifespan of existing assets, online PD testing helps target capital spend and manage operational cost. This cost-effective approach supports the financial strategy of managing operational costs while investing in infrastructure improvement.

4. Safety Enhancements:

   • Continuous or temporary monitoring of electrical systems ensures early detection of hazardous conditions, enhancing the safety of operations and reducing risks for maintenance personnel​​.

Implementation Strategy

To integrate and leverage PD testing into grid resiliency plans, the following steps are recommended:

1. Sensor Installation:

   • Deploy HFCT sensors across critical points in the cable systems and transformers to continuously monitor PD activity.

2. Data Collection and Analysis:

   • Utilize BlueBox technology for real-time data collection and analysis, leveraging AI and advanced noise removal algorithms to ensure accurate results.

3. Maintenance and Reporting:

   • Generate detailed reports on PD activity to guide maintenance decisions, ensuring timely and targeted interventions.

4. Applications:

   • Aged or end-of-life URD cable systems and transformer.

   • Problematic URD cable systems, temporary or permanent

   • QC on newly installed cable systems and transformers.

   • Commissioning of feeder or trunk cable systems

   • Substation, permanent or temporary PD monitoring

Conclusion

Integrating partial discharge testing and monitoring into a utility’s infrastructure strategy will significantly enhance grid resiliency, aligning with the company's commitment to reliability, safety, and customer satisfaction. By leveraging advanced technologies and proactive maintenance approaches, clients can achieve their long-term goals and ensure a robust and resilient energy grid for the future.