 The valves were series connected in three six-pulse valve bridges for each pole.The blocking voltage of the valves was 133 kV with a maximum current of 1,800 amperes, for a transmission rate of 1,440 megawatts with a symmetrical voltage of 400 kV against earth.After the Sylmar earthquake in 1971, the static inverter station in Sylmar was reconstructed due to damage sustained.