This report describes an enhanced test system (RTS-96) for use in bulk power system reliability evaluation studies. The value of the test system is that it will permit comparative and benchmark studies to be performed on new and existing reliability evaluation techniques. The test system was developed by modifying and updating the original IEEE RTS (referred to as RTS-79 hereafter) to reflect changes in evaluation methodologies and to overcome perceived deficiencies.

The IEEE Reliability Test System-1996. A report prepared by the Reliability Test System Task Force of the Application of Probability Methods Subcommittee

Overview of frequency domain measurement techniques of the complex permittivity at microwave frequencies is presented. The methods are divided into two categories: resonant and non-resonant ones. In the first category several methods are discussed such as cavity resonator techniques, dielectric resonator techniques, open resonator techniques and resonators for non-destructive testing. The general theory of measurements of different materials in resonant structures is presented showing mathematical background, sources of uncertainties and theoretical and experimental limits. Methods of measurement of anisotropic materials are presented. In the second category, transmission–reflection techniques are overviewed including transmission line cells as well as free-space techniques.

https://iopscience.iop.org/article/10.1088/0957-0233/17/6/R01/pdf

Frequency domain complex permittivity measurements at microwave frequencies

Major milestones in the development of high voltage direct current (HVDC) technologies and concepts were achieved in 1950s. Thanks to the high power thyristor switches (1960–70s), the HVDC technologies reached a significant degree of maturity in 1980s. The classical HVDC uses thyristor-based current-sourced line-commutated converter (LCC) technology. The advent of power semiconductor switches in 1980–90s, with turn on-off capabilities especially the IGBTs and IGCTs, and the on-going progress in this field, have introduced the conventional (two-level) voltage-source converter (VSC) technology and its variety of configurations, multi-level and multi-module VSCs, also as viable converter technologies for power system applications. The DC system is experiencing significant degree of re-emergence due to its potential to either directly address, or to facilitate resolving a large number of existing and anticipated interconnected AC power system steady-state and dynamic issues. HVDC technology made possible to transfer bulk power over long distances. In part I of this two-parts paper, comparative evaluations, studies, and review of HVDC versus HVAC transmission systems, are presented. Applications, different schemes of HVDC systems are also outlined.

High voltage direct current transmission - A review, part I

The transmission system is becoming ever more complex. Furthermore, demand for reliable supply of electricity is growing, increasing the need for a higher level of system reliability. A solution might be to incorporate controllable power components within the system. One such component is the HVDC link. However, in the domain of reliability models for HVDC and the component's impact on the overall transmission system reliability, there is still much work to be done. This is an important issue in future grid planning, especially with an increasing penetration of HVDC links within synchronous transmission systems acting as "firewalls". These links may prevent disturbances propagating in the system, which is a common cause of blackouts. This paper provides a broad introduction to the HVDC technology and a literature review of reliability assessments published within this area. It gives a background to and motivation for the technology. Published reliability assessments of the HVDC technology have been reviewed and categorized. One conclusion is that a large number of models and methods for the reliability evaluation of the HVDC system itself have been published, but very few on its impact on the composite system reliability. One future challenge to be solved is how the "firewall" properties of the HVDC can be quantified in a reliability assessment.

Introduction to HVDC Technology for Reliable Electrical Power Systems

Double 12-pulse ultra HVDC transmission systems of $\pm $ 800 kV and $\pm $ 660 kV have larger transmission capacities, more complicated configurations, more complex operation modes, and more components, in comparison to $\pm $ 500 kV or less HVDC transmission systems. Hence, the reliability evaluation of the ultra HVDC transmission system is more complicated than that of the HVDC system. To thoroughly describe different operating modes, this paper presents two new reliability measures for ultra HVDC transmission systems, that is, partial monopole forced outage times and partial bipole-forced outage times. Reliability evaluation models for individual subsystems, including converter transformers (CT), ac filters, converter valve groups, and smoothing reactors have been built considering operation modes and configuration characteristics. In particular, the reliability model of the CT subsystem was built by considering the type and the number of standby CTs, and that of the ac filter subsystem was built by considering the capacity state table of filters. A reliability evaluation model for ultra HVDC transmission systems was proposed by combining reliability logic relationships among subsystems and using the state enumeration method. Case studies of practical ultra HVDC transmission systems illustrate the correctness of indices and the proposed models. In addition, sensitivity analysis and standby analysis of major components were also conducted.

Reliability Evaluation of Double 12-Pulse Ultra HVDC Transmission Systems

Direct current (DC) links are finding increasing use throughout the world in the form of long-distance transmission and asynchronous interconnections. System reliability studies of a composite generation and transmission system containing a DC link involve modelling and evaluation of the reliability of the DC transmission line and performance of an overall composite system study with the DC link forming an integral part. The paper illustrates a technique for DC system reliability analysis using the contingency enumeration approach. A key element in this system reliability analysis is the creation of the reliability diagram from the single line diagram. A digital computer program was developed to evaluate the probability of failure, frequency of failure, and the mean duration of the possible performance levels for a DC link. The procedure and program were tested on a model DC system, and the results are presented to illustrate a proposed technique.

Incorporation of a DC-link in a composite system adequacy assessment-DC system modelling

The paper illustrates a procedure for adequacy evaluation of a composite generation and transmission system containing a direct current (DC) link. The transportation model option of the composite reliability (COMREL) program, developed at the University of Saskatchewan, is used to evaluate the composite system adequacy indices. The IEEE Reliability Test System (RTS) is augmented by adding a DC link and is used as the test system. The composite system load point and the overall system indices are calculated to quantify the adequacy of the composite system. The basic COMREL program was modified to accept a remote generation source connected to a composite system through a DC link. The analysis involves the construction of a generating capacity model at the remote bus and the movement of each generating capacity state through the DC line contingency state, without violating the carrying capability of the transmission line state or the generator state capability restriction. This type of analysis can be used to evaluate the benefits associated with design changes and capital expenditures in the DC facility. The paper presents the techniques employed for the composite system study and the results obtained for the modified RTS.

D.S. Ahluwalia

Papers

Incorporation of a DC-link in a composite system adequacy assessment-DC system modelling

Incorporation of a DC-link in a composite system adequacy assessment-composite system analysis