Russia, the largest country on earth, also has one of the world’s largest electricity networks, with 2.6 million kilometers of transmission lines and over 18,000 substations around the country. But the energy infrastructure, most of which dates from Soviet times, will need to be modernized soon, since experts predict that Russian electricity consumption will double by 2030.

Germany’s third-largest energy provider has embarked on an ambitious project to upgrade its 380/220-kV and 110-kV net work. For the first time, the grid owner EnBW Transportnetze AG as responsible transmission company and EnBW Regional AG as responsible distribution company have transferred much of the project organization responsibility to an outside party. The project is managed by a common project management.

In the past, high-voltage substations were always industrial-looking eyesores that, whenever possible, were banished from urban centers. Today, Siemens Energy's state-of-the-art technology, engineering and design of gas-insulated switchgear (GIS) substations mean that utilities can integrate high-voltage substations into urban settings in a way that makes them virtually invisible and entirely compatible with densely populated districts.

This paper outlines the opportunities the use of modern subterranean substations offers the challenges we face. For more than 40 years proven gas-insulated switchgear (GIS) has helped to secure efficient energy supply. Modern subterranean substations have to be "invisible", i.e. perfectly integrated in the surrounding area. Challenges such as access routes, emission control, fire protection, soil or ground water have to be solved by combining established know-how and experience. Local expertise and partnership are essential for obtaining approval from the respective authorities without problems as well as for on-time completion and reliable long-term operation of the substation.

This paper gives an overview about design of GIS, technologies, and worldwide experiences. The steps of technical development, stages of technical design, state of the art in the production, and quality insurance are explained with practical examples. Focus is given to applications worldwide with typical projects shown, including on-site works, sequences of erection, testing, and civil works. Explanations are given about the operational primary equipment (switching, grounding, disconnecting), secondary system, gas handling, maintenance, and monitoring. All requirements are met to have a safe handling of SF₆ even under the assumption of an increasing demand for the use in the electrical power supply.

The mixed technology substation combines the advantages of air insulated substation with gas insulated substations. In some cases this leads to new solutions in substations and delivers the highest value related to cost and performance. The MTS can also be used in new schemes of single lines in the context of making adventage of the todays high reliability of gas insulated substations, and the very long life times. The paper presents some excamples of applications are given to discuss the MTS advantages.

The article presents the applications of high voltage gas insulated substations. The following substations are presented: Jacksonville, Florida, USA; Taylor Street, Chicago, USA; Paget Sound, Bow Lake substation, USA; Saragans substation in Switzerland; Thermobahia in Rio de Janeiro, Brazil, Braintree; Barbara, outdoor Louisiana; indoor Tennessee and indoor Abu Dhabi.

Die gasisolierten Schaltanlagen (GIS) durchlaufen während ihrer Entwicklungszeit und im Fertigungsprozess eine ganze Reihe von Prüfungen, damit die Anlage im Betrieb sicher und störungsfrei arbeitet. Die Qualitätssicherung ist somit ein entscheidender Faktor, der sich über den gesamten Entstehungsweg einer Anlage erstreckt.

This report describes the different high-voltage tests and measurements during the life cycle of GIS and the related impact to the dielectric failure rate in service. Intensive development tests, routine tests and commissioning tests are the basics for a reliable design and proven product quality. Insulation monitoring in service may help to avoid unforeseen breakdowns.

Siemens has developed a highly innovative substation solution in close cooperation with substation operators. The "Highly Integrated Switchgear" - or HIS for short -combines the advantages of conventional outdoor installations with those of gas-insulated switchgear technology.

As an alternative to the insulating gas sulfur hexafluoride (SF ₆), gas mixtures have been analyzed for use in high-voltage gas-insulated switchgear or transmission lines (GIS or GIL). The main component of gas mixtures is nitrogen (N₂) with various slight admixtures of SF₆. The investigations were undertaken on real technical arrangements with the aim of arriving at design fundamentals for high voltage installations. These fundamentals were confirmed and verified with the aid of various high-voltage tests on GIL constructions. The insulating properties of the gas mixtures are examined under various voltage applications in comparison with pure SF ₆