SEAPA reports highlight Tyee projects
During the March 5-6 meeting of the SEAPA Board of Directors, the reports of operations manager Steve Henson and special projects director Eric Wolfe highlighted a number of projects and new information related to the Tyee Lake Hydroelectric project.
An analysis of a Petersburg electrical tower that is sloughing is a topic of importance in the report.
“Petersburg Municipal Power and Light discovered a bank that was sloughing near the outside set of anchors on Tower 76-1M on Mitkof Island. There are two anchors per pole of the three pole structure,” Henson writes. “Hugh Hall of Chatham Electric was contacted and staff requested he evaluate the situation. His initial evaluation was there is no immediate danger to the tower structure. He recommended soliciting civil engineering services to evaluate the stabilization of the bank and to contact Dryden and LaRue Engineering for an analysis of the anchor system, and possible need and placement of anchors if the outside set did fail. After examination of the structure design, it was determined that one anchor per pole is sufficient to guy the structure. Note that most of the structures on the Tyee system have redundant anchoring and that if it becomes necessary, there is room to install anchors closer to the structure away from the embankment.”
Henson added that stabilization of the ground was preferable to adding additional anchors for the tower.
“Since the anchors have not been compromised, we have determined that the best course of action is to pursue the stabilization of the slope which would be far more cost-effective than installing more anchors,” the report continues. “A task order has been issued to Tongass Engineering to provide engineering design and project management for the stabilization of the embankment. Completion of the project is expected by April 30, 2013.”
Henson’s report also provides information on the Wrangell Reactor Replacement project at the powerhouse near Bradfield Canal.
“The Wrangell Reactor replacement project management, engineering, and design have been awarded to Electric Power Systems, Inc. (EPS). Completion of the project has been tentatively set for December 2013,” Henson wrote, continuing with information on a reactor switching study. “A study to assess the feasibility of operating the system without a reactor in Wrangell in the event of a premature failure of the reactor has been commissioned. A joint effort by Segrity and Commonwealth to model the system without a reactor is underway. The results of this study are due by March 31. If this scenario is found to be feasible from a theoretical perspective, a procedure for energizing the system without the reactor will then be written by Segrity. Also addressed is the scenario of a line fault without the reactor in service.”
Segrity is a Colorado-based consulting firm retained by SEAPA for engineering issues.
Henson also addressed a Spill Prevention Control and Countermeasure, or SPCC plan, in his report.
“A Consulting Services Agreement and Task Order was issued to Oasis Environmental, an ERM company, to provide engineering and consulting services to update and certify our SPCC plans for both Tyee Lake and Swan Lake,” Henson stated. “The SPCC plan for Swan Lake is complete and accepted by SEAPA and is on file at the SEAPA office, KPU, and the Swan Lake plant. The Tyee Lake Plan is near completion.”
Additional projects mentioned as meriting importance by Henson include a propane generator for the gatehouse at Tyee, dock replacement at the plant’s harbor, obtaining a DOT permit for pole move in Wrangell along with replacing and realigning poles at Heritage Harbor, and a circuit switcher move in Wrangell set for 2014.
Wolfe’s report outlined new projects in the works for the Tyee plant.
“Supervisory-Control and-Data-Acquisition (SCADA) is part of electrical system operation,” Wolfe writes. “Most of SEAPA’s SCADA system is approaching 20 years of age; some of it on the north side dates to 1964 and is in dire need of replacement. Our original system, and our original SCADA RFP issued during 2010 was designed by traditional utility implementers meaning the advantages of the web were largely overlooked. The original RFP, answered by HSQ, to replace just the northern substation and Tyee equipment totaled $816,000.”
According to Wolfe, the RFP had a series of drawbacks, including proprietary terminal units, database software, and proprietary interface screens.
“Our revised RFP stresses generic hardware found in the industry (SEL, Allen-Bradley) and stipulates that SEAPA owns the licenses such that an independent third party can maintain the system. Our new RFP stresses web applications, and this stipulation requires us to have robust, secure communication paths between servers and devices.
Wolfe added that SEAPA designed and installed a new LAN/WAN system using Segrity and commissioned the LAN/WAN in January and that Segrity would continue as the SCADA project manager and technical advisor for the project.
The major categories of the RFP scope of work mentioned by Wolfe include new SCADA historian/servers at Tyee, Swan, and the SEAPA office, and new SCADA nodes and thin client-type applications at the Petersburg substation, Wrangell switchyard, and the Wrangell substation. The total projected cost for the project, through 2014, stands at $1,053 million.
According to Wolfe, the terms and conditions of SEAPA’s FERC License state that the agency must measure stage and flow on the streams upon which the Tyee project is located. Wolfe said logjams are causing headaches for measurement and that a new stream gauge will be required to rectify the condition.
“The present outfall discharge (spill) measuring methods once considered poor by USGS standards have deteriorated due to the continued pileup of logs at the outlet,” he writes. “Additionally, we need an accurate spill measurement for the Whitman true-up. Long-term, the stream gauge will allow us to better assess the basin as we evaluate expanding the Tyee project during the relicensing process.
The cost for the project, according to Wolfe’s estimates, varies between $1.18 and $1.46 million.
Although controls and electrical fitting have been received, the replacement of the control gates at Tyee Lake will have to wait until at least April or May according to Wolfe due to scheduling conflicts with plant employees and timing of the replacement of the propane generator. $35,000 has been budgeted for the project.