1. Insulated Bus Pipe (IBP), Revolutionary Alternative to Cables for Shipboard Power Distribution
March 12, 2019
NSRP 2019 All Panel Meeting

2. Background
Cables used since the advent of electrical distribution in 1800’s
Primary cable advancements are in standardization and insulation materials
Skin effect and size precludes the use of large conductors for AC
Only option for supplying high current loads is parallel cables
Cable bend radius is over twelve times the overall diameter, or 26.4” minimum for typical 400 MCM cable
Cables run after a ship is fully assembled, does not support modular construction
Cable repulls costly and time-consuming

3. About IBP
Touch-safe power distribution able to be shaped into complex shapes
Multiple sizes available
AC applications up to 36 kV and 6.5 kA
DC applications up to 60 kV and 7 kA
Shielding/protection options
EM shielding
High temperature capability
Stainless steel outer layer
Prefabricated sections installed similarly to pipes
Bend radius limited by mechanical strength of conductor
7.2kV AC/12kV DC at 2kA allows an 8” bend radius
Designed for 40+ year life

4. IBP Construction Copper or aluminum conductor, can be solid or hollow
UP to 30’ sections are standard
Alternating layers of insulating/semiconducting crepe paper vacuum impregnated with resin
Up to IP68 construction
High temperature coatings
Shielding options
Multiple connecting methods to suit application
Connecting sleeve constructed similar to IBP

5. IBP Connection methods

6. IBP Benefits/Advantages
Provides SWAP-C savings for increased endurance and design margin
Supports modular ship construction, savings cost, and schedule
Significant space and weight savings
Manufactured into complex shapes, can be placed in tight spaces
Rigid construction ensures accurate model
High abrasion resistance, increased survivability
Repairs easily accommodated, only the damaged section is replaced

7. IBP Product tested circa 2005
IBP product tested at NAVSSES Philadelphia circa 2005 in support of early Ford class development
IBP not governed by any MIL-STD
Product tests based on electric cable tests as agreed between NAVSSES Philadelphia and interested program officers

8. Status of qualification
Category & Site
Test
Status
Shock & Vibration at
AeroNav Lab Inc.
MIL-STD-901D Shock, Grade A, Medium Weight
Approved for unrestricted Navy shipboard installation
MIL-STD Vibration
Vendor Shock/Vibration Fixture
Fixture may require qualification
Electrical Compliance Testing at
KEMA Powertest, Inc.
Shield Continuity
Pass
Insulation Resistance (initial and after AC Voltage Withstand test)
Partial Discharge (Corona) Level
Conductor Resistance
AC Voltage Withstand
Basic Insulation Test (BIL) to IEC 60502
Three Phase Bolted Fault to ANSI C37.23
EMI Radiated to MIL-STD-461E (RE 101)
Free Air Ampacity

9. Status of qualification (con’t)
Category & Site
Test
Status
Installation Compliance Testing at
General Cable Corp
Watertight Integrity
Pass
Centering and Circularity
Inconclusive; minor concern as test specific to cable not IBP.
Drip
Shrinkage
Gas Flame
Fail; but retested and passed in 2014 and 15
Acid Gas Equivalent
Pass except for ground wire, a minor concern
Halogen Content
Smoke Index
Toxicity
Ordinance Survivability Testing
Aberdeen Proving Ground (APG)
Riflemen
Improved survivability over medium voltage cable
Fragmentation

10. Advancements
US manufactured IBP demonstrated to the Navy in a lab environment 1/24 through 2/1
Incorporated in the power circuit during MVDC grounding testing at FSU CAPS facility

11. IBP Observations from demo
No issues observed during the two (2) week demonstration
AC IBP sections were exposed to 4.16 kV AC RMS line-to-line, 250 amps peak
DC IBP sections were exposed to as much as 5 kV DC, 200 amps
DC IBP is not expected to increase parasitic capacitance:
~5.4 ηF IBP to ground (100 KHz to 20 MHz)
~70 ηF overall DC side (including IBP) to ground
Real-time temperature sensing of IBP coupling bolts:
Identify coupling bolts that come loose over time

12. Project Status
Land Based Case Study of Insulated Bus Pipe for Ship Design
Culminated in lab test demo at FSU CAPS 1/24-2/1 2019
Final Report to issue 3/20
Qualification Testing of Insulated Bus Pipe (IBP) for Shipboard Introduction
Conduct electrical characterization, installation compliance, and shock and vibration tests
Build a low magnetic signature co-axial IBP for medium voltage direct current (MVDC) shipboard application
Generate IBP interface methods for power and loads
Generate a roadmap leading to IBP shipboard installation
Qualify a section of IBP for US Navy shipboard use

13. Conclusion
Provides numerous benefits to designers, builders, and the Navy
Benefits increased with high power loads
Increased budget margin for future upgrades
IBP has already passed a number of tests, and will work with Tech Warrant Holder community to determine qualification path
Once qualified, IBP will be available for shipboard integration

14. Status of qualification
Team Members: Tefelen, AeroNav Laboratories (Lead Test Lab), General Dynamics Bath Iron Works
Supportive Shipyards: Newport News Shipbuilding & Ingalls Shipbuilding
Certification Authorities: American Bureau of Shipping & Naval Surface Warfare Center Philadelphia Division
SEA 05Z approval of final qualification tests is required