George J. Anders

Energy price forecasting in the Ontario competitive power system market

This paper introduces a method for forecasting energy prices using artificial intelligence methods, such as neural networks and fuzzy logic, and a combination of the two. The new approach is compared with some of the exiting methods. Various factors affecting the market clearing price are investigated. Results for the Ontario electricity market are presented.

Bidding strategy design for different types of electric power market participants

This paper presents a methodology to design an optimal bidding strategy for a generator according to his or her degree of risk aversion. A typical thermal plant is assumed to be located in the Ontario electricity system to apply this methodology for two types of participants: risk averse and risk seeker.

A comprehensive study of outage rates of air blast breakers

This paper presents results of an extensive study launched by Hydro One Networks aimed at determining air blast circuit breaker reliability measures from a statistical analysis of outage data. The study examines how the breaker failure rate depends on such factors as equipment age, voltage level, manufacturer, and number of repairs. Planned outage rates due to equipment maintenance were also investigated. Results presented in this paper are based on outage records involving 318 breakers and covering a period of 12 years. The results can form input information for probabilistic risk analysis studies.

Modelling of Dynamic Transmission Cable Temperature Considering Soil-Specific Heat, Thermal Resistivity, and Precipitation

This paper presents an algorithm for the estimation of the time-dependent temperature evolution of power cables, when real-time temperature measurements of the cable surface or a point within its vicinity are available. The thermal resistivity and specific heat of the cable surroundings are varied as functions of the moisture content which is known to vary with time. Furthermore, issues related to the cooling effect during rainy weather are considered. The algorithm is based on the lumped parameters model and takes as input distributed temperature sensing measurements as well as the current and ambient temperature. The concept is verified by studying a laboratory setup of a 245 kV cable system.

Transmission expansion planning: A discussion on reliability and “N−1” security criteria

This paper proposes a methodology to solve the multi-stage transmission expansion planning (TEP) problem based on metaheuristic optimization techniques, as load and generation evolve. A discussion on how to consider security criteria using the well-known deterministic “N−1” approach and the probabilistic reliability-based method is presented through a case study system.

Spectral Graph Theory and Network Dependability

The paper introduces methods of graph theory for ranking substations of an electric power grid. In particular, spectral graph theory is used and several ranking algorithms are described. The procedure is illustrated on a practical numerical example

Ampacity Calculations for Cables in Shallow Troughs

This paper presents the findings of an investigation concerning a calculation method for current-carrying capability (ampacity) of cables located in a shallow trough. The investigations proceeded in two parallel directions. On the one hand, an extensive search of published and unpublished records dealing with the subject was performed. The second path of investigation involved studies applying finite element analysis. Sensitivity analysis was also performed. In both cases, the recommendation is to use the same approach for determining the current rating of cables in a trough. They both use the cable rating in “free airv as the basis and add an extra thermal resistance to take into account the effect of the trough. Based on the investigation of the previous work and the finite element analysis, two new equations were developed for the external thermal resistance. The proper choice would depend on the field or laboratory tests that would confirm our findings or lead to the modifications of the rating formulae. In the absence of any additional information, it is recommended that the calculations be performed using one of three methods listed below. The methods are listed from the most to the least conservative. 1) method given by a new equation based on the finite element analysis; 2) method given in the IEC standard 60287; 3) method given by a new analytical equation presented in this paper. The comparison of the calculated results with the available test data shows that the method 3) above, the least conservative one, gives a good agreement with the measured values.

Ampacity Reduction Factors for Cables Crossing Thermally Unfavorable Regions

When power cables cross regions with unfavorable thermal conditions, temperatures higher than the design value can occur. If the region is wide enough, the rating of the cable will usually be based on the assumption that the entire route is characterized by the same conditions. In a majority of cases, the unfavorable thermal environment will be very short, usually a few meters (e.g., street crossing). In these cases, the effect of the crossing is usually ignored. The conductor temperature in such cases may be much higher than in the remainder of the route, however, and cable derating is required. Analytical solutions are almost never used to determine the effect of unfavorable short sections of the route on the ampacity of the rated cable. The main reason no computations are performed is an absence of either derating formulas or derating tables (curves) and not the lack of a need. To fill this gap, an analytical solution for the computation of the derating factors has been developed and is presented in this paper. The solution is simple and accurate enough to be suitable for standardization purposes. A numerical example involving a pipe-type cable crossing a street is presented to show the effect of street crossings on the ampacity of the cable circuit. In this practical example, the ampacity of the pipe-type cable has to be derated considerably.

Advanced modeling techniques for dynamic feeder rating systems

This paper describes the technical details of an advanced model for use in real-time cable rating systems. Real-time cable rating systems perform calculations of steady state and emergency cable ratings in real-time; several such systems have been installed to maximize asset utilization without compromising cable system reliability. An example of a complex tunnel installation, featuring four self contained fluid filled and cross-linked polyethylene cable circuits, is described in detail, highlighting key issues of relevance to real time systems.

Basic fault tree analysis for use in protection reliability

Fault tree analysis (FTA) is a tool originally developed in 1962 by Bell Labs for use in studying failure modes in the launch control system of the Minuteman missile project. The tool now finds wide use in numerous applications, from accident investigation to design prototyping, and is also finding use for protection and control related applications. This paper provides an elementary background to the application of FTA for use in protection applications. The construction of the fault tree as well as the use of reliability data is considered. A simple example is presented. The intention is to provide a brief introduction to the concept, to allow users to at least understand how a fault tree is constructed and what can be done with it.