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The electricity industry of the Nordic countries went through a major restructuring during the 1990s. A wholesale market with significant competition has been established. Nord Pool was established in 1993 as a Norwegian electricity exchange, and extended its trade to Norway and Sweden in 1996. It thus became the world's first multinational exchange for trade in electric power contracts, and presently it is the only truly international electricity market. There is one market operator, and there are five system operators. Each country has its own regulatory agency. There are no general cross border tariffs. In 2001, power contracts worth nearly NOK 412 billion, about 55 billion Euro, were cleared by Nord Pool, and the combined volume of contracts traded was 2769 TWh, that is more than seven times the physical consumption. An open market with a common framework has made the Nordic market the most liquid electricity market in the world. Three of the countries have full retail market access. Since deregulation of the electricity industry started, restructuring has taken place in all countries resulting in mergers and acquisitions. There is an ongoing concentration of ownership in the wholesale market, and the concentration of the production side causes concern. Index Terms--Deregulation, electricity markets, power exchange.

Load-frequency control (LFC) is used for many years as part of the Automatic Generation Control (AGC) in power systems around the world. In the synchronous Nordic power system, however, this function (termed secondary control) has so far been handled with manual control actions. Increased operational strain due to new HVDC connections in the next decade will make it increasingly difficult to maintain the current manual control system. In this paper a model of the interconnected power systems of Norway and Sweden is used to show how introduction of AGC might aid the system operator in handling the increased strain. However, the classical LFC based on the Area Control Error is difficult to implement in a deregulated environment. An alternative concept is thus introduced where selected units are automatically following load changes on the HVDC connections. This ramp following controller (RFC) supported by manual control seems to be a promising option. Key Words: AGC, Load-frequency control, Secondary control, Deregulated system