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Innovative Low Head Hydro –The StreamDiver® in Action NWHA Small Hydro Workshop 2016, Wenatchee , WA USA
Agenda
1. StreamDiver® Introduction
2. Design Concept and Testing
3. Nussdorf Pilot Plant Operations
4. Summary, Results and Outlook
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Worldwide, there is still tremendous potential for the use of
low head hydropower for power generation.
Decentralized hydropower generation is sustainable, renewable
and supports economic development of remote areas.
However, decentral, low head power plants have specific
requirements regarding commercial viability, availability,
maintenance and environmental aspects.
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
StreamDiver® Application Range Covers
Heads From 2 - 8 m (up to 26 ft.)
Turbine classification
Application by head and flow range
A single unit generation ranges from below
50 kW up to above 750 kW depending on
the available head and flow.
The StreamDiver® covers the low
head, low power range next to
conventional designs like Kaplan,
Francis or Pelton.
StreamDiver® application range (single unit)
5 different runner sizes (modules)
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Reduction of O&M Costs is One Key
Premise and Today’s Focus
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Reduced O&M Cost & Risk
Oil-free Plant Solution
Ease of Project Execution
Reduction of Civil Cost
Clarity: The Simplified Design of the
StreamDiver® Ensures the Highest Reliability
Generator & terminals
Stator vane
Runner
Housing
Shaft, bearing assembly
1
2
• Turbine housing with guide vanes
• Radial and axial bearing
• Shaft ends
• PMG generator
• Runner
• Bulb nose
1
2
3
4
5
6
3
2
3
4 5
6
Standard version: Non-regulated, direct-driven turbine generator unit
No dynamic seals, cooling water system, lubrication oil system, excitation system, or runner or guide vane regulation
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Two Unique Features are Most Relevant:
Bearing Lifetime and Cooling Concept (1/2)
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Lubrication
Water flow
Heat transfer
Water inlet
Water inlet
Water flow
Heat transfer
Two Unique Features are Most Relevant:
Bearing Lifetime and Cooling Concept (2/2)
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
1. Water exchange• Bulb fills with river water before start-up
• Minimal exchange during operation (minimal sediment exchange)
2. Water circulation• Shaft rotation will circulate water in bulb to avoid hotspots
• Circulation transports heat to the housing elements
3. Heat transfer• Discharged flow passes the bulb and housing
• Passive, convective cooling of the bulb
4. Lubrication• River water inside the bulb generates lubrication film• Contained sediments are processed by hard coated shaft
Bearing Performance and Lifetime:
Endurance Tests at the Test Rig in Heidenheim
Test rig assembly and installation
Scaled model with same drive-train dimensions
Intermediate measurements of wear (interval of 6 w)
Hard-coated surface at shaft, soft shells and pads
• >18,000 hours of operation
• Tested with different densities
of quartz in bulb1
• Brenz river installation
• Low head of 2 meter results in
relatively low bearing load factor
1 Due to the high hardness rate (Brinell scale), quartz is considered as most relevant sediment which causes wear of the shaft coat The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 3,000 6,000 9,000 12,000 15,000 18,000 21,000
Re
lati
ve
we
ar
[%]
Operating hours [hrs]
axial bearing
radial bearing DE
radial bearing NDE
Results Indicated Wear on Hard Coat with No
Significant Correlation with Quartz Density
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
NDE DEHydraulic force
(runner)
Weight
(drive train)
The axial thrust bearing shows most significant wear
Degradation of hard coat on thrust ring by a factor of 2.7 compared to radial bearing at the non-driven end (NDE)
0,5 g/l 1 g/lriver water
<< 0.5 g/l
2 g/l
Quartz
content
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Relative wear:
Ax 2.7
rad DE 1.7
rad NDE 1.0
Test Rig Configuration Transferred to
Nussdorf Prototype Design
Bearing lifetime influencing factors: test rig compared to prototype design Nussdorf (module size SD 13.10)
Additional factors: capacity factor (full load hours per year, number of start & stops, ambient conditions (temperatures, ...)
Factor Test rig Nussdorf
Stationary loads1 different sizes + generator
Load factor (hydraulic) Head = 2 m, 7.7 kW Head = 3.6 m, 314 kW
Water quality2 Up to 2 g/l (Quartz) < 0.5 g/l (Quartz)3
NDE DEHydraulic force
(runner)
Weight
(drive train)
1 Considers design dimensions (bearing distance, clearances, size), stationary loads from drive-train
2 Due to the high hardness rate (Brinell scale), quartz is considered as most relevant sediment, which causes wear of the shaft coat
3 Based on assessment report about sediment transport in the Danube river
Expected relative wear (average)
Factor compared to test rig
• Axial 2 - 3
• Radial DE 6 - 7
• Radial NDE 4 - 5
Expected lifetime (in years, full load)
75% wear allowed, max. value applied
• Axial 16
• Radial DE 11
• Radial NDE 26
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Prototype in Nussdorf (Austria) Now Completing
4 Years of Maintenance-free Operation
Turbine Data:
• Power Unit: SD 13.10 (Ø 1310 mm)
• Power: 314 kW / max. 450 kW
• Net head: 3.58 m / max. 4.68 m
• Flow: 9.96 cms
• Generator speed: 333 rpm, 50 Hz
Project Status:
• In operation since August 2012
• Operating hours: > 30,000 hrs 1
• Exported electricity: > 8.0 GWh 1
• On-site inspections: 2 (down: 3 days)
• Maintenance services: 0
Status: April 2016The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Housing After 42 Months of Operation Shows
Slight Organic Layer, but Intact Coating
• Generator leakage test okay, temperature and leakage sensors in function
• Anti-corrosion coating intact (covered by thin organic layer)
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
The Stainless Steel Runner is in Excellent
Condition and Shows No Notable Abrasion
• Runner blade condition excellent, no issue with clearances of rotating
parts (blade tip, runner housing, ...)
• Guide vane coating intact with some impacts on leading edge
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
The Power Output Versus
Measured Gross Head Per Year
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
The performance of the machine has been stable (constant slope); tendency to have improved over the years (A)
(B): Power spread (bias of data for same gross head) mainly influenced by intake conditions (head losses due to pollution level)
A
B
A. Delta of 25°C between hottest
and coldest period (river water)
B. Linear correlation of generator
temperature and power
Temperature Levels in Bulb and Generator
Stator Confirm Passive Cooling Concept
Generator phase temperature vs. power output
Seasonal effects (quarter 1 to 4)
Generator phase temperature vs. water temperature in bulb
Temperature rise of generator below design value (class F/B)
A. Temperature rise of
up to ~40°C (design
class B: 80°C)
A
B
B A
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Measured Wear at the Radial Bearing (NDE)
Confirms Projections from Endurance Test
Expected replacement of the radial NDE shaft end is required after 23 years (initial projection: 26 years)
Replacement is recommended when 25% of the remaining layer is reached – extrapolated: 30,000 x 75/11 = 204,000 hours = 23 yrs
Profile 1
3 2
• Wear is not constant over measured profiles on shaft line
• Relative wear with maximum of 7 - 11% after 30,000 operating hours
• Additional sensors detect wear limit for predictable and planned replacement
7 – 11 %
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Summary and Outlook
• StreamDiver® low head technology for heads up to 8 m
• The innovative design minimizes support systems to maximize reliability
• Passive cooling concept and bearing design are core features
• Test and proof of design successful
• Lifetime projections exceed initial design values
• Full-scale Nussdorf prototype now goes into its fifth year of operation
• Full load operation, no maintenance required so far
• Retrieval and detailed inspection planned after 5 years
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Bearing Lifetime Projection and Monitoring:
Project Application Band for 50 - 100 % full load
Application
• Content of hard particles
< 2 g/l (e.g. quartz)
• Water temperature up to 30°C
• Maximum wear is monitored:
• Maximizing lifetime
• Predictive maintenance
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21
Standard design configuration (SD 7.90 – SD 13.10)
Recommended replacement at 25% of the remaining hard coat layer
Radial DE
Axial
Radial NDE
Lifetime Projection (Radial DE):
Full load 3 m head 8 m head
50% 24 yrs 14 yrs
100% 12 yrs 7 yrs
The StreamDiver® in Action | NWHA Small Hydro Workshop 2016, Wenatchee , WA USA | 2016-09-21