* ISO to pay $200,000 fine to settle allegations * ISO has improved training, revised some procedures Dec 14 (Reuters) - California's power grid operator has agreed to pay $200,000 to settle allegations that it violated electric reliability standards in connection with a short San Diego blackout in the spring of 2010. The Federal Energy Regulatory Commission (FERC) said in an order on Friday that the California Independent System Operator (ISO) admitted violating reliability standards following an investigation by FERC's Office of Enforcement. "We reacted very quickly to this error, we acknowledged the error and are going to do what FERC has told us to do," said Steven Greenlee, ISO spokesman. On March 31, 2010, the California ISO, in conjunction with the power company San Diego Gas & Electric (SDG&E), scheduled the 322-megawatt (MW) Central La Rosita II power unit in Mexico to provide power on April 1, 2010. However, La Rosita II suffered an outage on the afternoon of March 31 and was not available to meet its schedule for April 1. The ISO knew La Rosita II was not available but failed to plan to replace the power scheduled from the unit, according to the FERC order. One megawatt can power about 800 California homes. SDG&E is owned by California power company Sempra Energy . Privately-held power generator InterGen owns Central La Rosita. InterGen is based in Massachusetts. Shortly before midnight on March 31, 2010, the ISO granted a request from Calpine Corp's 604-MW Otay Mesa power plant to shut at midnight. One minute before midnight, an alarm alerted the ISO operators that generation in the San Diego area had dropped below the required level. The FERC order said the operators were not adequately trained on how to respond, and just after midnight they started to shed load in the San Diego area, leaving about 250,000 SDG&E customers without power for 43 minutes. Greenlee said while the operators made an error, they acted out of an "abundance of caution" to protect the integrity of the grid. Since the outage, the agency has enhanced its training, revised some operating procedures to reduce confusion and assigned operating engineers to the control center at all times to assist power system engineers. San Diego has suffered other power problems since then. In September 2011 a blackout left 2.7 million customers in Southern California, Arizona and Baja California in Mexico without power.