the route, at Ivaiporã, there is a branch into 500 kV, 60 Hz AC, delivering into the Southern grid. By introducing, in 1989 and later, series capacitors in Ivaiporã (at of the line) and Itaberá (at ) the capacity grew from 4300 MW to 6300 MW. Reliability In its first few years, the project suffered many failures of converter transformers, with six in the first year of commercial operation and twelve in the first four years. Modifications had to be made to all of the transformers on the system, and led to markedly improved performance, with no failures in years 4-10. On 29 May 1989, a complete quadrivalve in converter 5 of the Foz do Iguaçu converter station was destroyed by a fire which started as a result of a water leakage from a cooling pipe. The affected converter was out of action for 14 months. Similar incidents on the Rihand–Delhi project in 1990 and the Sylmar Converter Station of the Pacific DC Intertie scheme in 1993 led to CIGRÉ publishing guidelines on the design of thyristor valves in order to reduce fire risks. Electrodes Each bipole can be operated also as monopole and is equipped with a grounding electrode. The electrode lines of both bipoles are installed on wooden poles and consist of 2 x 689 mm2 1272 MCM conductors. The electrodes for Foz do Iguaçu Station are situated at Santa Terezinha de Itaipu at and at Alvorada do Iguaçu at and are connected to the converter station via lines of 15.5 km and 16 km length respectively. The electrodes for San Roque Station are situated at Córrego Boa Vista at and at and are connected to the converter station via lines of 66 km and 67.2 km length respectively. Waypoints See also High-voltage direct current HVDC converter station HVDC converter Electrode line List of HVDC projects References Electric power infrastructure in Brazil HVDC transmission lines 1984 establishments in Brazil Energy infrastructure completed in 1987