Recommended Test Methods for Underground Power Cables Containing Superabsorbent Materials Kenneth E. Bow, Kable Consult LLC and Richard M. Ellis, Cable Materials Inc.

INTRODUCTION Growth in Use of Underground Cables Use of Water Blocking Materials to Control Longitudinal and Radial Water Flow Prevent Growth of Water Trees SAP – Superabsorbent Materials Are Used in Sheath and Conductor to Block Water SAP Materials in the Form of Powders or Encapsulated in Fabrics, Tapes and Yarns

Objective of This Paper Propose a Modified Test Method and Test Media to Predict the Service Performance and Life of Water Blocked Underground Power Cable Propose Test Requirements that More Adequately Reflect Field Conditions Propose a Path to Harmonization of ICEA and IEC Test Standards

Use of SAP Materials in Cable Use of Powders and Yarns to Block the Flow of Water Between the Wires in the Conductor Use of Semiconducting Tapes to Block Water around the Conductor Use of Semiconducting Tapes to Block Water in the Core-Metallic Shield Interface Use of Semiconducting or Non-Conducting Tapes in the Metallic Shield-Jacket Interface

Properties of SAP Materials Absorption and Retention of a Certain Quantity of Water Absorption Speed to Quickly Stop the Flow of Water High Permeability of the Hydrated SAP to Prevent the Capillary Transport of Water Resistance to Hydrolysis and Gel Degradation over the Service Life of the Cable

Water Penetration Testing – State of the Art SAP with Rapid Swell Speed/Large Capacity Distilled or De-ionized Water/Tap Water Longitudinal Application of a Water Head to the End of the Cable – Test of Conductor Application of Water at a 90 Degree Angle – the “Tee” Test – Test of Sheath Interfaces Wide Variability on Test Duration, Water Type, Temperature and Thermal Cycling

Proposed New Test Media Standard Ionic Solution Based on ASTM D1141 – 98(2013) “Standard Practice for the Preparation of Substitute Ocean Water” Blend of 3% of Ocean Water and 97% Distilled Water Represents Soil Water with Effectively a 0.1% Ionic Solution

Proposed Standardized Test Method for Swell Height of SAP Materials Use Method Specified in CENELEC HD 605 S2 Section “Cup and Ram” Type of Swell Test Eliminates Variations from One Vendor or User to Another Meets Need for a Standardized ICEA Test

CONCLUSIONS Standardize the Test Media as an Ionic Solution Standardize the Swell Cup Test Method Standardize the Cable Water Penetration Test Method to Include Thermal Loading for Power Cables at Operating Temperatures Method to Include Cable Operation at Emergency Rated Temperature (ERT) Tests Must Reflect Service Conditions

Photograph of 69 kV Laminate Sheath Cable