HomeMy WebLinkAboutAkutan Town Creek Hydro Improvements 2010
Akutan Town Creek Hydro
Improvements
Prepared for:
City of Akutan
Prepared by:
David Buss, P.E.
ELECTRIC POWER SYSTEMS, INC.
3305 Arctic Blvd., Suite 201
Anchorage, Alaska 99503
March 31, 2010
Akutan Town Creek Hydro Improvements
3/31/2010 1
1 Controls Recommendation
The controls for the hydro consist of a hybrid system that incorporates the Thompson and Howe
“Product G” governor (load bank control) with a PLC for automation and integration with the
existing diesel generator. The Product G governor provides the speed control capability of the
hydro by using a resistive load bank. The produce G will quickly add/remove energy being
diverted to the load bank to respond to load changes in the system, thus maintaining a fixed
frequency. This is done by use of SCRs and control of the firing angle of those SCRs. The
Product G governor was part of the original installation of the hydro product. In 2003, the
controls were modified to incorporate a GE PLC that would allow automation of the hydro along
with the ability to operate the hydro generator in parallel with the hydro plant diesel generator.
The PLC allows the Product G to control the unit when it is in isochronous mode. When the unit
is in parallel mode, the PLC takes control of the needle valves, load bank and deflector to
maintain a fixed load on the hydro. The PLC will control load on the generator depending on the
available water and load on the diesel.
The manufacturer of the hydro turbine (Canyon) was contacted to discuss options for replacing
the existing controls. The manufacturer indicated the product G is still being used on this size
unit. There would be little or no benefit to replacing the existing controls as they would be
replaced with a similar system with the same functional control. EPS recommends proceeding
with improvements on the existing control system.
The improvements recommended by EPS will focus on improving the operator interface. It has
been noted that the difficulties with operation of the plant is typically due to a lack of
information being passed back to the operator. Additional points will be added to the HMI that
notify the operator of conditions that need to be met prior to issuing a start command to the
hydro.
Akutan Town Creek Hydro Improvements
3/31/2010 2
EPS has identified the following areas of improvement in the existing controls:
1. Upgrade HMI/Server to include screen at hydro plant. Upgrade will include a system
with flexibility to easily add additional screens at places such as the diesel plant, future
Loud Creek Hydro, etc. - $40,000
2. Modify control screens for simpler operation and provide additional training. - $10,000
3. Add control points (valves, control switches, etc) to the HMI for sequential start
sequence/instructions for the operators and complete automation of the hydro. - $25,000
4. Replace radio connection with fiber (fiber installed as part of the distribution upgrades)
- $5,000
5. Purchase spare parts; Product G governor, PLC cards, relays, etc. - $30,000
6. On-Site training and installation of the above. - $40,000
The total recommended estimated cost for the above upgrades is $150,000.