Program 2

Project 1 - Field-Aged Cable Testing

The objectives of this research performed on field-aged cable cross linked polyethylene cable samples, removed from service by DSTAR member utilities, were to:

  1. Evaluate the linkage between impulse duty and insulation degradation in field-aged cross linked polyethylene primary distribution cable.
  2. Determine if a recently developed partial discharge site detector can successfully assess cable insulation aging.
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Tagged: P1-2, P2, Equipment Testing/Evaluation, System Protection, Engineering Guidelines

Project 2 - Semi-Conductive Jacketed Cable Investigation

The objectives of the project were to: 1) investigate the impulse performance of semi-conductive (semi-con) jacketed cable when subjected to impulses from the overhead system, 2) assess the susceptibility of semi-con cable to induced neutral currents during ground strokes, and 3) quantify secondary surge currents caused by nearby ground strokes to the primary semi-con cable circuit. Read More →

Tagged: Equipment Testing/Evaluation, P2-2, Engineering Guidelines, P2, System Protection

Project 3 - Switching Surges in Underground Distribution Systems

Field tests, augmented by simulation studies, were performed to:

  1. Characterize voltage transients generated by routine cable and capacitor switching operations.
  2. Compare the performance provided by different switching devices.
  3. Generate guidelines for switching practice and arrester application which can minimize switching surge overvoltages applied to underground distribution systems.
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Tagged: P3-2, P2, Equipment Testing/Evaluation, System Protection, Engineering Guidelines

Project 4 - Ferroresonance Guidelines for Modern Transformer Applications

Based on extensive field tests, this research had the following objectives:

  • Characterize ferroresonant behavior when grounded-wye padmount transformers are switched.
  • Develop formulas for estimating ferroresonant overvoltage magnitude as a function of transformer and cable parameters.
  • Provide detailed guidelines specifying the maximum cable length which can be switched with a given transformer without exceeding a critical overvoltage magnitude.
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Tagged: Equipment Testing/Evaluation, System Protection, Engineering Guidelines, P4-2, P2