November 2021 COMET News

  • Comet Logo

Active Projects:

  • Awarded with the NAVY-ONR contract “Investigation of reliability of Laminated BusBars under Electrical, Thermal, and Mechanical stresses LBB-ETM
    • Ending 2021.
  • Awarded with the ARPA-E project "High Power Density Motor Equipped with Additively Manufactured Windings Integrated with Advanced Cooling and Modular Integrated Power Electronics", which is coordinated by Marquette University and where CAPS takes care of the insulation system design, testing and, in the second phase, possibly monitoring
    • Started
  • Awarded with the ARPA-E project “Novel Light-weight Mega-watt Cable System for Large Electrified Aircraft”, which is coordinated by GE. Our work is modelling aging mechanisms, developing stochastic life models, PD measurement and monitoring technology
    • Started on September
  • Awarded with a new NAVY-ONR contract “Electrical insulation system reliability in the PEPDS project” (included in the broad Power Electronic Power Distribution System (PEPDS) project) 
    • Started
  • Awarded with a new NAVY-ONR contract “New high-Temperature dielectric materials with better Thermal and Electrical short-term and long-term Performances- NETTE”.
    • started
  • Awarded with the NAVY-Hepburn & Son SBIR “Medium Voltage Direct Current (MVDC) Partial Discharge and Space Charge Test Apparatus for Cable and Insulated Bus Pipe (IBP)
    • Started
  • Awarded with a new NAVY contract “Electrical Ship Assets: aging modelling, Reliability and Condition Assessment in MV power cables and busbars supplied by DC and AC modulated voltage, ESARCA” 
    • Started on October.


  • The chamber endowed with variable pressure, humidity, broad range of temperature and high voltage up to 50 kV has still to be delivered (3 months expected delay).
  • New PWM testing generator prototype is being developed, under validation testing, voltage up to +- 10 kV (expected two months delay, due to MOSFET delivery).
  • Continuing development of the automatic, innovative software for a brand-new PD detector. It can measure PD with any type of waveform (from DC to power electronics), reject noise, identify PD, evaluate component health...automatically and without the need of experts.
  • Training for COMET members is undergoing.
  • New space charge measurement system, PEA, installed.
  • New charging-discharging measurement system, installed.
  • High-field lab slowly build up and used (delays in any equipment delivery).
  • Very last news: DURIP granted from NAVY to buy UV camera, function generator, power amplifier to generate any type of voltage waveform up to 20 kV.


"Measuring Partial Discharges under Power Electronics Waveforms: from Slow to Ultra-fast Voltage

Impulse Risetime

Part 1: How to extract PD signal from noise


With increased voltage and faster switch rise time, the major issues faced while designing insulation systems for inverter-fed rotating machines is how to measure partial discharges, PD, correctly and evaluate the partial discharge inception voltage and the repetitive partial discharge inception voltage, PDIV-RPDIV, in type and qualification tests for Type I insulation. The current PD measurement techniques as per IEC 60034-27-5 involve the use of high pass filters to suppress the switching disturbance and retain the PD. This approach, however, may be not effective for fast risetime and high-amplitude voltages, where the disturbance spectrum spreads out in the higher frequency range and can overlap with the PD spectrum, rendering any frequency domain approach poorly effective. Therefore, new techniques for separation of PD from voltage switching disturbance must be investigated -> Time-based approach