Abstract: The topic of 600 volt underground secondary cable is seldom discussed at ICC meetings where medium and high voltage underground cables receive most attention. However, underground secondary cables form an important part of a utility system considering larger utilities install more than 1 million ft. of underground secondary cable per year and spend several million dollars annually on secondary underground cable repair costs. This Educational Program will focus on the topic of underground residential and commercial services and underground streetlight cables. Presentations from the cable manufacturers will cover the manufacture, design, materials and industry specifications covering secondary cables. Learn about the latest secondary cable design technologies and their potential benefits. Presentations from the utilities will focus on their experience with underground secondary cables and splices. The Educational Program will also feature a presentation on the results of a utility survey on secondary cables conducted specifically for the benefit of utilities attending this session. All files are available in the PDF format
For additional details on the presentations please refer to the abstracts listed below:
- The Manufacture of 600 Volt Underground Secondary Cables
Nick Ware, Southwire.
Abstract: Manufacturing techniques for 600V utility cables have changed in the past several years. These products demand the highest quality and reliability yet are viewed as commodity products in our industry. The result is a constant pressure for improved techniques and efficiencies in manufacturing. The various techniques of manufacture and design will be discussed, as well as some newer product designs that can further improve reliability.
- History of Ruggedized URD Cable Development
Kyle Cope, Pirelli Cables & Systems NA
Abstract: From its beginnings as a pair of copper conductors wrapped in rubber to the current use of polyethylene, the idea of URD cable has been with us since the 1800s. Polyethylene insulated secondary URD cable has been around since the 1960s and has seen some design and process (manufacturing) changes over the years. Current technology, the concept of "ruggedizing" cable, has greatly improved the performance over basic polyethylene insulated secondary URD, but has been in use since the mid 1970s. The next advancement in the development of this design is here - Secondary URD cable that will actually heal itself if damaged.
- Industry Standards for 600 volt Underground Secondary Cable
Bruce F. Vaughn, Alcan Cable
Abstract: Cable manufacturers utilize industry standards, and utility customer specifications for the manufacture of 600 volt underground cables. These industry standards are developed by cable manufacturers or user groups, and/or certification organizations and include cable material and test requirements. The Insulated Cable Engineers Association standards S-105-692, “Standard for 600 volt Single Layer Thermoset Insulated Utility Underground Distribution Cables”, and S-81-570, “Standard for 600 Volt rayed Cables of Ruggedized Design For Direct Burial Installations as Single Conductors Or Assemblies Of Single Conductors”, and Underwriter’s Laboratories Standard 854 for Service Entrance Cables will be reviewed. Material, testing, and qualification requirements will be included
- Overview of Polyethylene Used for 600 volt Underground Secondary Cable
Paul Caronia, Dow Chemical Company.
Abstract This presentation will be an overview of the polyethylene materials used in 600 volt underground secondary cable. We will provide a review of the types of polyethylene used, the key material parameters and the advantages/disadvantages of the different grades of polyethylene used in today’s 600 volt cables. Additionally, we will discuss the peroxide and moisture crosslinking processes used to produce these cables, and why each is used, along with an overview of the new developments in moisture cure technology.
- Failure Rate of Bare Concentric Neutral 600-Volt Cable
Neal Parker, Puget Sound Energy
Abstract: In the mid-1960s Puget Power installed a 600-volt cable that was made of two insulated phase conductors and a bare tinned-copper concentric neutral. The construction was called “flat twin” or “ribbon” cable. Neal Parker will present the results of his investigation into this cable’s performance. The almost total lack of reliable data resulted in unique investigative techniques to estimate the number of these cables and how many fail each year. From this information and anecdotal evidence, the failure rate was estimated and a corporate approach is recommended.
- How Reliable are Your Underground Secondary Circuits?
Timothy J. McLaughlin, Public Service Electric & Gas (PSE&G).
Abstract: There has been much interest of late in the growing problem of secondary connection failures. Fortunately, there are a few solutions to this nagging industry problem. PSE&G methodically tracks its underground primary failures. We know when they failed, why they failed and how our customers were affected. With secondary failures we are far less diligent. The reason for this at PSE&G as well as other utilities is that secondary failures are viewed as a small problem. They have almost no impact on your reliability numbers as only one customer is usually out at a time. They are low-cost when compared to primary failures, and they are usually easy to repair. The problem comes in when you add all of these failure totals up and see how they impact the bottom line. This presentation will focus on the sources of these failures and the way PSE&G has attempted to fix them.
- Secondary Cable Failure Statistics at TXU Electric Delivery Company
Richie Harp, TXU Electric Delivery
Abstract: The TXU Electric Delivery underground system consists of about 19,000 miles of cable. This is divided into 13,000 miles of medium voltage cable and almost 6,000 miles of low voltage secondary cable. Most of the attention for cable failures is on the medium voltage cable, but there are a significant number of secondary cable failures that can be almost as costly as the medium voltage cable failures. This presentation will address the secondary cable system, the failures experienced on this system and the cost of these failures.
- The History of Secondary Cable Designs at Commonwealth Edison Company
John Hans, Commonwealth Edison Company
Abstract: Commonwealth Edison has approximately 27,000 conductor miles of 600-volt class cables on the system. Ruggedized cables have been used for residential applications for the last 25 years. The presentation will review the historical usage of 600-volt cables and their respective performances.
- ICC Educational Program Secondary Underground Cable Survey
Steve Szaniszlo, Power Cable Consultant
Abstract: The results of a survey conducted specifically for this ICC Educational Program on 600 volt underground secondary cables used for residential and commercial services and underground streetlight cables will be reviewed. This survey explores 600 volt underground secondary cable usage, designs and splices used, cable failure rates and solutions evaluated to mitigate cable failures by the contributing utilities. This survey was conducted on a strictly volunteer basis for the Insulated Cable Committee, Educational Program for the benefit of attending members and guests.
Evolution of EPR Compounding (3.6 MB
Carl Zuidema, The Okonite Company
Abstract: There are four elastomeric materials that have found widespread use as the primary dielectric in wire and cable for power delivery: cis-polyisoprene, (natural rubber), polybutadiene co-styrene - (SBR), polyisobutylene co-isoprene - (IIRR) polyethene co-propene - (EPR). The art of rubber compounding began with the invention of vulcanization of natural rubber by Charles Goodyear in 1844. This talk will focus on the development of rubber technology as applied to the dielectric of electrical wire and cables. We will briefly review the development of natural rubber compounds, the invention of synthetic rubber and the particular compounding requirements of each of these. An emphasis will be placed on the relationship between polymer structure and physical properties, as well as the relationship between compounding variations and finished properties. This leads to a discussion of the different types of EPR compounds, defined by the ICEA as classes I, II, III and IV. Manufacturing methods for mixing and processing EPR will be reviewed. Lastly we will discuss semi-conducting EPR compounds as used for cable shields.
Black EPR (63 KB PDF)|
Ronald F. Frank, Cable Engineering Consultant
Abstract: Data is presented on 5kV to 46kV shielded cable insulated with black EPR made by one cable manufacturer from 1964 to 1970. To achieve maximum performance characteristics at this time a small amount of carbon black was added to the EPR compound, which gave it a black color. Service experience with this cable has been good.
EPR Mechanical and Thermal Properties (549
Steven Boggs, Electrical Insulation Research Center Institute of Materials Science, University of Connecticut
Abstract: The mechanical and thermal characteristics of several EPR compounds will be discussed based on new experimental data for several EPR compounds. The thermal conductivity, thermal expansion, heat capacity and mechanical properties of these compounds were measured as a function of temperature using modern equipment and the data presented.
Accelerated Wet Testing of Medium Voltage
EPR-insulated Cables (926 KB PDF)|
Edward E. Walcott, William S. Temple, General Cable Corporation, Suffern, NY and John T. Smith, III, General Cable Corporation, Scottsville, Texas
Abstract: A brief history and overview of North American accelerated wet-aging test procedures is presented. A review of accelerated wet-aging time-to-failure and fixed time aging tests (followed by electrical test diagnostics) for medium voltage EPR insulated power cables is presented. A discussion of the relevance of these tests to actual field service performance is also discussed.
In Service Performance of EPR Cables
Installed in the Memphis Light Gas And Water (MLGW) Electrical Distribution
System (128 PPT)|
Abstract: This presentation will provide a brief background relating to the decision to install EPR insulated cables rather than HMWPE and XLPE cables, 25 year performance history, and field aging studies performed at MLGW.
Performance Evaluation of EPR
Underground Distribution Cables|
Carlos Katz, Cable Technology Laboratories, Inc.
Abstract. - Because of the increased usage of EPR insulated cables and the limited data available, starting in 1994, EPRI, ESEERCO and Orange & Rockland Utilities (O&R) funded a project to develop information to quantify the aging of various EPR cables. Five types of EPR cables, manufactured by different companies, were aged for 7 years at three locations: namely, in CTL laboratories under 2.5V0, in the field at O&R at 1 and 2.5 V0. The field sides were part of actual utility circuits. Laboratory load conditions were adjusted to mimic field conditions. Cables were periodically tested for a number of properties. Test results indicate that there is no major difference in the overall performance of the five EPR insulated cables. However, differences in the characteristics of the components may lead to conditions, which can result in premature failure, as it occurred on a number of occasions while aging one of the cables in the laboratory. Other circumstances lead to the field development of partial discharges in another cable.
EPR Use at High Voltages – Cost Justification
(300 KB PDF)|
Rachel Mosier, Northeast Utilities
Abstract: Northeast Utilities (NU) has been installing 115-kV ethylene propylene rubber-insulated (EPR) cables since 1999. We use these cables in our substations where we do not have room for overhead lines. Our service reliability is excellent, having never suffered a failure for any reason on these lines. However, the losses in an EPR cable are relatively high compared to other types of insulation. This presentation will detail how NU cost-justifies an EPR cable by calculating the point at which the cost of losses per foot of the EPR cable exceeds the cost per foot savings of the EPR cable over other types of insulation.
Transmission Class EPR Power Cables (2.9
Robert E Fleming, The Kerite Company
Abstract: This segment of the EPR Power Cables Session will focus on Transmission Class Cables. It includes a brief history of early Underground Transmission Projects, increase in installed cable and Current Type Projects. Also included is information on Underground verses overhead and EPR verses Alternate Designs and Materials. The advantages and disadvantages of EPR cables as far as electrical, mechanical, installation, maintenance and testing of the new cable installation will also be presented.
AEIC Guide for Reduced Diameter Cable (49
Michael L. Walker, Reliant Energy
Abstract: This presentation will provide an overview of The Association of Edison Illuminating Companies’ (AEIC) guide for reduced diameter cables. Many cities in the United States and countries around the world have and aging underground cable system. This guide was developed to provide an alternative to complete duct bank replacement.