MINNETONKA WATER TREATMENT PLANT ELECTRICAL UPGRADES
Minnetonka, MinnesotaAbout the Project
The City of Minnetonka has eight small water treatment plants (WTPs) which each consist of one remote submersible well, one vertical turbine well, two booster pumps, and two filters.The age of all electrical equipment within the WTPs was beyond its useful life, and concerns were raised over the reliability of the plants.
The City retained AE2S to upgrade all electrical components in WTPs 3, 6, 11, 12, 13, 14, and 15, following a phased approach of upgrading one treatment plant per year.
Project Details
Date: 2012 – 2020
Client: City of Minnetonka
Key Project Elements
- MCC Replacement
- Emergency Power Generator
- Energy Efficient Lighting
- Flow Paced Chemical Feeds
- I&C Upgrades
- Arc Flash Analysis
Improvements Provide Operational Flexibility and Increased Efficiency
Improvements at the plants consisted of the replacement of the existing 480V three-phase service, motor control center (MCC), and SCADA panel and circuitry. A new exterior-mounted main utility breaker/portable generator breaker connection interlock was installed to ensure continued services during power outage situations.The existing MCCs, which utilized starters, were replaced with MCCs utilizing variable frequency drives (VFDs) to allow increased operational flexibility of the wells and booster pumps, as well as to provide increased energy efficiency. Existing lighting was upgraded to energy efficient lighting.
Upgraded Instrumentation and Controls for Advanced Treatment Monitoring and Optimization
Instrumentation and Controls were upgraded for additional treatment monitoring and control. Chemical feed systems were also modified, and instrumentation was installed to allow flow pacing of the chemical feed system.
On the most recent plant, the valve monitoring and control were added to SCADA to automate the backwashing process and monitor differential pressure across filter media in order to optimize backwash cycle times.
Reliability Results
The electrical and control system upgrades significantly increased the reliability of the WTPs. The City is now realizing cost savings from energy efficiency improvements and flow-paced water treatment. In addition, the City now has the peace of mind that even in the event of a power outage, water treatment will continue.Improved Operator and Electrician Safety
After each plant was finished, an arc flash analysis was completed by taking data from the installed equipment and creating arc flash labels which show incident energy levels. This allows electricians working on any energized electrical equipment to select a proper level of Personal Protective Equipment.Also included as part of the arc flash analysis, is a coordination study which determines the circuit breaker trip settings so the circuit breakers operate correctly.
