Declassified 341st SMW unit histories

Read from the scan by GLM-OCR; expect the odd misread word.

## Continuous

to the Glengarry substation at Lewistown and the other to the Harlowton substation. The Glengarry substation feeds the Hilger substation with 50 KV lines and Hilger feeds the Winifred substation with 50 KV lines. The sites are fed by 7.2 KV lines. (U)

A 7.2 KV transformer shorted in the line to site E-3 at 1450, 16 March 67. This transformer is located on a farm two miles south of the Winifred substation. Automatic reclosure switches at Winifred substation opened, and were reclosed manually after transformer replacement later in the day. This caused the Brine Chiller problem at E-1. The transformer was in the West phase. It was not determined which phase this corresponds to at the sites. Sites E-3, E-5, E-6, E-9, and E-10 transferred to Standby Power. Sites E-1 transferred to Direct Current (DC) operation. (U)

On 28 March 67, the 341st SMW in conjunction with the Montana Power Company conducted a switching test on the 50 KV high voltage line between the Harlowton and Glengarry substations. The test was performed at the request of OOAMA/OONE as a part of the initial Echo Flight incident investigation performed at Malmstrom. The intent of the test was to verify correlation, if possible, between high voltage switching and launch facility shutdown or other launch facility faults. (U)