South Selma, Alabama

Initial Mobilization / Completion Date

8/31/2020 - 1/15/2021

Contract Amount:



USACE - Mobile District
POC: Joan Rensink

Job Number:


General Contractor

Koontz Electric Co., Inc.
PM: Stephen Andrews

Jones Bluff Lock and Dam, is a lock and hydropower dam located on the Alabama River near Selma and Montgomery Alabama, and is operated by Mobile District. Power is produced by four Westinghouse 21.5 MVA generators rated at .95 PF and stepped up via two 42 MVA generator step-up transformers. Three 115 KV transmission lines owned by Alabama Power Company are fed through a main and transfer bus switchyard arrangement. Switchgear lineups for generators 1 & 2 and 3 & 4 also supply 480V station service power via two 1000KVA station service transformers. In 2010, the project purchased but had not yet installed two new 15KV arc-resistant switchgear featuring new vacuum circuit breakers and plenums for arc flash gas venting. The two switchgear lineups include the unit breakers for the four generating units plus the two station service transformer breakers. This switchgear differs slightly in dimension from the existing units and, therefore, either the gear required modification in order for the new gear to fit in the same location. Koontz Electric Co., Inc. was awarded the installation contract for the new switchgear to be furnished to the contractor as Government Furnished Equipment (GFE).

Koontz Electric removed the existing 15KV generator switchgear for units 1-2 and station service breakers, and units 3-4 and station service breakers. KTR installed two government-furnished new 15KV generator switchgear for units 1-2 (breakers 710 & 720) and station service no. 1 (breaker 812), and units 3-4 (breakers 730 & 740) and station service no. 2 (breaker 822). All cabling (comprised of both low and medium voltage cabling) from removed equipment was replaced and new conductors to new equipment were installed. The existing surge arrestors and capacitors in the new government-furnished equipment were replaced with new surge arrestors and capacitors. The existing non-segregated bus from the generators and GSU was modified to connect to the new 15KV switchgear including all connectors and fasteners.

Koontz Electric Co., Inc coordinated with the switchgear manufacturer and a sub-contractor to design, fabricate, and install the balance of the plenum system for each of the new switchgear to vent the exhaust to a safe area. A section of the synchronous condensing pipe was removed. The pipe was reinstalled with additional flanges added for easier removal in the future. Necessary commissioning and testing were performed satisfactorily with USACE engineers as well as plant operators and technicians.

This project was completed on time and under budget.