Pipe Cable Systems Research Articles

The application of real-time monitoring and rating to HPOF pipe cable systems

The Boston Edison Company has installed real-time monitoring and rating equipment on two independent pairs of 115 kV HPOF (high-pressure oil-filled) pipe-type cables. The real-time systems are remotely located at cable terminal locations so that critical data inputs can be hard-wired to the computing processor. Real-time information is made available via analog SCADA (supervisory control and data acquisition) connections and also by IBM PCs equipped with modems, which can call the remote systems to view real-time conditions or unload historical data. A PC software package complements the real-time system and gives planners, system operators, and cable engineers the ability to simulate cable system operation in an offline environment. In general, the identification of effective earth parameters in real-time is shown to result in increased emergency and normal ratings by replacing the conservative assumptions that must be made at the design stage with accurate real-time data. Lightly loaded circuits have exhibited large increases in short-time emergency ratings, as they normally operate at relatively low temperatures. >

The Application of Real-Time Monitoring and Rating Equipment to HPOF Pipe Cable Systems

The Boston Edison Company has installed realtime monitoring and rating systems on two independent pairs of 115 KV HPOF pipe-type cables. This paper describes these installations and gives some results of their operation. These circuits exhibited large increases in short time emergency ratings because they normally operate at relatively low temperatures. The identification of effective earth parameters in real-time generally results in increased long term and normal ratings because of the conservative assumptions that must be made at the design stage. The real-time systems are remotely located at cable terminal locations so that critical data inputs can be hard-wired to the computing processor. Real-time information is made available via analog SCADA connections and also by IBM-PC's equipped with MODEMs which can call the remote systems to view real-time conditions or unload historical data. A PC Software package compliments the real-time system and gives Planners, System Operators, and Cable Engineers the ability to simulate cable system operation in an off-line environment.

Optimized PPP-insulated pipe type cable system for the commercial voltage range

An EPRI project with the objective of developing an optimized 345 kV paper-polypropylene-paper pipe cable system is discussed. Highlights of the design and manufacture of the new reduced-wall cable are detailed. Pertinent aspects of a major corollary development, establishing a US domestic supplier of PPP, are described. Laboratory qualification tests suggest that reasonable cable optimization is achieved. An optimized PPP joint design is described. The economic advantages and versatility of this new cable system are summarized. >

A Versatile Computer Method for Computation of Conductor Temperatures in Cable Terminations and Pipe Cable Systems

A computer method, originally developed for the determination of ampacity and ratings of cable. terminations, has been expanded to cover also the thermal analysis for accurate ratings of underground pipe-type cables. The versatile computer method is able. to handle many situations where the traditional methods are either inaccurate or too complex. The main advantage of the method is its ability tp provide fast solutions in abnormal emergency situations where the traditional methods will tend to produce incorrect ratings. The new computer method will. also be of substantial value in evaluation of new underground pipe-type cable systems or similar installations.

A Versatile Computer Method for Computation of Conductor Temperatures in Cable Terminations and Pipe Cable Systems

A Versatile Computer Method for Computation of Conductor Temperatures in Cable Terminations and Pipe Cable Systems

A General Method for the Calculation of Pipe Cable Pulling Forces

The accurate prediction of cable pulling forces is essential for the design of pipe cable systems. This knowledge makes it possible to avoid overconservative design practices and to achieve substantial capital savings during construction. Calculation procedures used previously have only a limited ability to account for complex pulling path geometry. This paper develops a general tension model and a solution algorithm suitable for use with a programmable calculator. The model has been used on the design of actual cable installations. Comparisons are made between calculated and measured lengths and tensions for a wide variety of path conditions

Laboratory Development of ± 600 KV DC Pipe Cable System

Final results of a U. S. DOE-sponsored development program for a DC pipe cable system are summarized, providing a basis for optimized design. Long-term performance of DC cable models under accelerated stress provides essential data regarding operating safety factors. Design requirements for optimum performance are discussed in relation to future commercial system applications. Close-to-optimal cable and accessories are recommended for Waltz Mill, based upon laboratory test results and with due cognizance of modern arrestor protective capabilities and system coordination.

A General Method for the Calculation of Pipe Cable Pulling Forces

The accurate prediction of cable pulling forces is essential for the design of pipe cable systems. This knowledge makes it possible to avoid overconservative design practices and to achieve substantial capital savings during construction. Calculation procedures used previously have only a limited ability to account for complex pulling path geometry. This paper develops a general tension model and a solution algorithm suitable for use with a programmable calculator. The model has been used on the design of actual cable installations. Comparisons are made between calculated and measured lengths and tensions for a wide variety of path conditions

Pressure Drop in a Model of a Forced Cooled Pipe-Typr Electric Cable System with Cable Snaking

An experimental study was conducted of the pressure losses in a scale model of a high pressure oil filled (HPOF) pipe cable system with a wave-like snaking pattern of the cables inside the pipe. In HPOF systems, snaking can be caused by longitudinal thermal expansion of the cables between fixed points of support when the cables are placed under electrical load. Friction factors were determined for a Reynolds number range of 200 to 3800 and longitudinal expansion up to 13.2 percent for cables with and without wire wrap (skid wires).

EPRI-Manufacturers 500/550 KV Cable Research Project-Potheads NO. 2 - Summary of Field Test Performance at Waltz Mill

This paper presents the test history and results of the post test examination of four G&W EHV potheads installed on cables A and B during the original two year field evaluation program for the 500/550 kV oil pipe cable systems and the extended testing at 750 kV, or elevated cable conductor temperatures, at the Waltz Mill test facility. This research project was sponsored by the Electric Power Research Institute (EPRI).

550 kV and 765 kV high pressure oil filled pipe cable system

This paper presents the results of a comprehensive 2 year scheduled acceptance test program performed at Waltz Mill Test Site under the auspices of EPRI on a 500/550 kV high-pressure oil-filled pipe cable system, described in detail in reference 1. Test data are also included for the extended phase of the original program where the cable was evaluated for higher rated voltages up to 765 kV. A detailed review of the test data as obtained at Waltz Mill and laboratory analysis of electrical characteristics of oil impregnated cellulosic laminar dielectric are presented. The temperature/voltage capabilities of cellulosic paper insulated oil impregnated EHV cable are determined and included in this paper.

Preliminary qualification of a HPOF pipe cable system for service at 765 kv

Tan δ (dissipation factor)data on Cable System B is updated to include the full 2-year 500/550 kV test program at Waltz Mill and the 10-month 765/800 kV extended test program. This data is analyzed, demonstrating no change with time of tan δ for the system. Particular attention is paid to the paper splice, which exhibits a thermoelectric stability limitation at the 765/800 kV level. The outstanding performance of the PP/C splice is emphasized. Consideration of the operation of a very highly stressed oil impregnated paper insulation HPOF pipe system at 765 kV is suggested, including potential single circuit transmission capacity calculations.

Glass-Reinforced Epoxy-Resin Pipe for Pipe-Type Cable

Cable engineers have recognized for many years that losses which occur in the steel pipe of pipe cable systems appreciably increase ac resistance and greatly reduce possible ampacity of such systems. Nonmagnetic pipes did not offer a practical solution to the problem since available materials contributed essentially the same degree of loss to the system as steel pipes. Hence, from time to time, engineers have focused their attention on nonmetallic pipes as a means of reducing losses. This work shows that one of three plastic pipes examined by the authors effectively stopped the entrance of moisture and caused no deterioration of the cable or pipe oil. Therefore, from a technical standpoint, it provided an effective enclosure for pipe cable. However, the cost of such pipes is still too high to make them economically feasible.

Cathodic protection of transmission and distribution underground cables

This paper contains a brief description of the original 125-kv Somastic-coated pipe cable system of the Florida Power Corporation, and the additions to that pipe cable system. The graphite anode-rectifier type of cathodic protection system originally installed, and the deep ground bed-rectifier addition are discussed. Operation of the pipe cables is tied in with the type of cathodic protection installation selected. In one area, both pipe cables and 12-kv lead-sheath cables are being protected by a common rectifier. The operation of this deep ground bed on the pipe cable and lead-sheathed cables is explained. Mention is also made of damage made by shellfish to a 12-kv submarine cable crossing.

Devices Used in Corrosion Control of Power Cables

Abstract This paper describes the various devices which are used in the corrosion control of underground power cables. Many of these devices have been used for a long time but the present paper describes a number of useful improvements in such devices as the electrolysis switch, the test current interrupter, and the cathodic protection and forced drainage rectifiers. The use of silicon power rectifier as an electrolysis switch is described. A method of grounding and corrosion protection of a pipe cable system is also outlined. 7.7, 5.2.1

Current-Carrying Capacity of Pipe-Cable Systems Under Steady-State and Transient Cyclical Loading Conditions [includes discussion

Current-Carrying Capacity of Pipe-Cable Systems Under Steady-State and Transient Cyclical Loading Conditions [includes discussion

Procedures for calculating the temperature rise of pipe cable and buried cables for sinusoidal and rectangular loss cycles [includes discussion

It has been customary in calculating the temperature rise of cables in duct to take account of the nature of the load cycle, since this has the effect of reducing the temperature rise from that which would result if the load were maintained continuously at a constant value. With the advent of pipe-cable systems and the increased use of directly buried cables in the United States, the problem naturally arises as to how to calculate the effect of the load cycle in these cases as well. This matter is discussed at some length in an AlEE conunittee report (ibid., vol. 70, pt. I, 1951, pages 45-52). While this report presents the results of many calculations of the effect of various loss cycles on a number of typical cable systems, it does not offer a simplified procedure for making such calculations. This paper presents such a procedure. The procedure involves merely the determination of the internal thermal resistance of the cable system in conventional manner, and adding to it the effective external thermal resistance as given in a table as a function of cable diameter and loss factor. By the use of simple nomographs, the procedure is made to include the effects of changing the earth constants, depth of burial, or frequency of the loss cycle. A rigorous straightforward method of solution of the temperature rise under sinusoidal loss cycles is also given for use where additional accuracy is required.

Reactance of Large Cables in Steel Pipe or Conduit

The determination of reactance of large conductors in steel pipes or conduits has not been susceptible of practical computation but is required for estimating the voltage regulation of pipe cable systems. The present paper gives the results of tests made by Electrical Testing Laboratories (ETL) under the auspices of the Insulated Power Cable Engineers Association, on cables from 750,000 to 2,500,000 circular mils. These data have been supplemented by data from other sources, extending the lower limit of size to 4/10 American wire gauge. Empirical formulas have been developed to include all intermediate sizes and spacings. These formulas are based on the principle of deriving a self-GMD (geometric mean distance) from the a-c/d-c resistance ratio, and using an augmented axial spacing to allow for the magnetic effect of the pipe.