The Public Utility Commission of Texas (PUC) has ordered Southwestern Public Service Company (SPS) to pay a US$36,000 penalty for not meeting service quality and reliability standards from 2001 to 2004.

The 1999 Texas electric restructuring law requires a transmission and distribution utility to operate its system so that no distribution feeder with more than 10 customers remains among the worst-performing 10% of its feeders for two consecutive years. The PUC determined that SPS committed 18 violations of these standards. Performance is measured according to the System Average Interruption Duration Index (SAIDI) and the System Average Interruption Frequency Index (SAIFI).

The law also requires SPS to maintain and operate its system so that no feeder sustains a SAIDI or SAIFI value more than 300% greater than the system average of all feeders for two consecutive years. The PUC determined that SPS committed 23 violations of these standards.

SPS also committed one violation in which the SAIDI exceeded the system-wide SAIDI standard of SPS by more than 5%.

The law is designed to require electric transmission and distribution utilities to upgrade their worst-performing feeder systems.

SPS, a subsidiary of Xcel Energy, generates and distributes electricity through an interconnected system to approximately 267,000 customers in the Texas Panhandle, including Lubbock, Amarillo and Plainview.