The impacts of a historic cold snap on the Texas electricity market continued to reverberate on Monday, as one electric power supplier filed for bankruptcy and another was sued by the state attorney general in connection with the crisis.

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Waco, TX-based Brazos Electric Power Cooperative Inc. said Monday it has filed for Chapter 11 bankruptcy protection, citing the cold weather event that caused extended power outages throughout the state and sent electricity and natural gas prices skyrocketing.

Brazos, a cooperative of 16 power distributors serving more than 1.5 million Texans, said it initiated the financial restructuring “to maintain the stability and integrity” of its system.

Before the Feb. 13-19 stretch of frigid temperatures, “Brazos Electric was in all respects a...