On June 12, a high voltage AES power line in downtown Indianapolis was damaged, leading to highly unusual cascading events resulting in a partial steam system outage and distribution system leak.
Citizens Energy Group employees collaborated with AES to quickly determine the cause of the power line damage and the resulting power outage to Citizens’ steam plant, responded quickly to restore steam service to its customers, and conducted after-action reviews once the steam service interruption was resolved.
The loss of power to Citizens Perry K steam plant resulted in a steam outage for the utility’s 250 PSIG (gauge pressure) steam system. In addition, the plant experienced a failure of the Uninterrupted Power Supply (UPS), contributing to a longer restart time for steam service. Once power was restored, and as operators were bringing the system back, a leak was reported in the distribution system. Subsequent investigation revealed that the leak was due to the failure of an expansion joint, likely an indirect result of the steam outage and re-start. Of Citizens’ thermal customers impacted, most had steam service restored in 2.5 hours.
To mitigate future incidents like this, Citizens has taken the following actions:
- Added additional electrical topics to agendas for standing monthly meeting with AES
- Changed UPS and controls components
- Increased diagnostics, reporting, and testing
- Automated backup for pneumatic controls
- Updated notification process