Monitoring of events in the power system provides a great deal of insight into the behavior of the system. Events with impact on the entire power system typically occur in or near the transmission network and are therefore best monitored at transmission system substations. This puts great demands on the equipment and in general restricts the use of the data since it becomes property of the transmission system operator. An alternative is to measure at lower voltage levels. This paper documents the close agreement between voltage and frequency at low and high voltage levels during a remote and a nearby fault in the transmission network. The very high quality of the data suggests that valuable information about the transmission system can be obtained at lower voltages.Index Terms-Power system dynamic stability, power system faults, power system monitoring.

Two 500 kV series capacitors came on line in Ontario, Canada in 2011 with the purpose of improving transmission capacity in a power interconnector and of meeting rising demands on power transmission within the province of Ontario. The series capacitors are equipped with a novel Fast Protective Device representing an important step forward in series capacitor protection philosophy and technology. The paper will dwell on this as well as on other salient design features of the series capacitors and also highlight their benefits for the functionality of the power system. In particular, the limiting of transient recovery voltage over existing line circuit breakers will be highlighted, as well as the impact on series capacitor design in conjunction with long, inadequately transposed overhead lines.

Loads such as mine hoists, mmmg shovels, crushers, etc for mining are demanding and also sensitive to dips and fluctuations in feeding voltage, thereby depending on secure, high quality power supply. At the same time, mining complexes are often remotely located, where power is weak and unpredictable. A traditional way to deal with poor power supply is reinforcing the grid by building new lines, uprating voltages to higher levels, or building local power plants to supply parts or the total of the load. Such measures, however, are expensive and time-consuming, if at all permitted. A more cost as well as time effective way may be to introduce FACTS, thereby utilizing existing facilities more efficiently. The paper highlights SVC and STATCOM for improving power supplies to mining industry, offers some salient design features, as well as gives examples of current, successful FACTS installations for the purpose in the world.

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The paper outlines the installation of a STATCOM for suppression of flicker generated by an electric arc furnace in a steel plant connected to a weak feeding grid. Salient design features of the STATCOM are given, and performance results from field measurements are presented and discussed.