Showing papers in "IEEE Transactions on Power Delivery in 1986"

Recommended Dielectric Tests and Test Procedures for Converter Transformers and Smoothing Reactors

Abstract: The dielectric conditions which are unique to converter transformers and smoothing reactors are examined. Both steady state and transient situations are discussed. Two additional tests are recommended for this equipment - a long term dc applied potential test and a polarity reversal test. Formulae are developed to calculate proposed test levels, and guidelines are presented concerning allowable partial discharge levels during the tests.

DC Transmission Terminating at Low Short Cirucit Ratio Locations

Abstract: In the past few years, application of dc links for the expansion of power transmission systems has been growing. A major application has been interconnection of large ac systems. The location of such dc interconnections are dictated more by economic and environmental considerations than by the purely technical aspects of the interconnection. Use of existing facilities (transmission lines, substations, etc.) lead to minimum new construction, minimizes need to acquire new land or rights-of-way and can also benefit a project with an early in-service date. Environmental issues such as locating new installations in less farmed areas outweigh technical aspects of a project. Therefore, quite often dc interconnections are located where the strengths of the ac systems being interconnected by the dc link are close to the dc power rating of the link. With such interconnections, system design and operation is influenced by several factors, including temporary overvoltages, reactive power compensation, ac voltage regulation and stability, and low-order harmonic resonances. The extent to which these factors cause concern is related to relative strength of the ac transmission system compared to the rating of the HVDC terminal. The relative strength of an ac system for such purposes is often described in terms of an indicator called the Effective Short-Circuit Ratio (ESCR); this term is explained later in the paper. Until recently, system planners were using an ESCR of 2.5 as the lower limit for considering interconnection of systems by dc. Advanced techniques developed by the industry have made it possible to successfully operate dc links located at terminals with ESCR's much less than the previous rule-of-thumb limit of 2.5.

Radial and Axial Temperate Gradients in Bare Stranded Condctor

Abstract: This paper considers two aspects of thermal rating calculations which may affect both clearance and conductor strength - the radial temperature drop between the steel core and surface of ACSR conductor and locally high temperatures due to wind shielding of even short sections of conductor. Measurements and analytical models are presented for each phenonenon.

2GW Britain-France H. V. D. C. Link Transition Joint - Steady State Stresses

Abstract: Methods are described for the calculation of the steady state electric stresses in the SF6 filled transition joint used to connect the sea to the land cables in the Britain-France cross-channel hvdc link. The calculated stresses are within the capabilities of the various insulation materials. The resistivity of the Voltalit (a silicon based epoxy) cylinder and SF6 common surface is seen to exert a considerable influence on the magnitude of the stresses.

Background and Methodology for Analyzing Step and Touch Potentials near Transmission Structures Part I Background

Abstract: This paper provides background Information for analyzing step and touch potentials near transmission structures. A companion paper provides engineering evaluation for analyzing these potentials.