C5: Operations and Equipment

In this session, you’ll learn about the linkages between modeling, operations, and performance, via real-life case studies.

Presentations are:

Centralized Operations: The Past, Present, and Future, presented by Aaron Dale, Duke Energy

Understanding the Causes of Pressure Pulsations in Hydraulic Turbines As a Basis for Design of Machines Able to Operate from 0-100% Power, presented by Bernd Nennemann, Andritz

Lessons Learned from Comparisons between Turbine Contractual Guarantees and Actual Field Performance Tests, presented by Albert Mikhail, KGS Group – HydroPower Performance Engineering Inc. (HPPE)

Details about each presentation and the speakers are below:

Centralized Operations: The Past, Present, and Future, presented by Aaron Dale, Duke Energy

Duke Energy began as a hydroelectric company with its first hydro station coming online in 1904. For nearly a century, the company’s hydro assets were operated nearly the same – each site manned 24/7 and operated at the request of the transmission operator.

In the late 1990s, the company began the monumental project of modernizing and automating the hydro fleet. New PLC control systems coupled with the expansion of the internet allowed for the assets to be dispatched remotely. The result was a centralized operations center (Hydro Central) located in the company’s headquarters. As FERC compliance grew and additional assets were added, the responsibilities of the operations center expanded.

As solar facilities were added, it was quickly recognized that these assets needed continuous monitoring. Considering financial restraints, the solution resulted in a joint hydro and solar operations center—it became known as the Regulated Renewables Operations Center (RROC).

The growth of renewables has propelled the RROC’s responsibilities to include more than 3,600MW of hydro and 1,500MW of solar generation across the Carolinas, Florida, and Indiana. Most recently, the RROC’s role has been expended by the integration of 47MWhr of lithium energy storage.

As we continue the clean energy transition, renewables (solar, wind, and energy storage) are expected to grow at unprecedented rates. More than 10GW of these assets are expected to be integrated into the Duke Energy service territories by 2035 plus an additional 1,680MW of pumped storage. This will drive change within the RROC as hydro is used to balance the non-dispatchable resources. It is critical that we invest today in our employees, control rooms, operational software, and processes to meet that future need.


Understanding the Causes of Pressure Pulsations in Hydraulic Turbines As a Basis for Design of Machines Able to Operate from 0-100% Power, presented by Bernd Nennemann, Andritz

For a variety of reasons, such as market variability and the high remuneration of ancillary services, hydraulic turbines are more and more operated over a wide range of power. This can lead to extended operating times between speed-no-load (SNL) and about 50-60% of power as well as at overload. That type of operation is outside the previously considered “normal” or typical operating range. Depending on where a hydraulic turbine operates within the 0-100% range of power, specific hydraulic phenomena occur. Many of these are associated with flow unsteadiness, resulting in pressure pulsations.

This begins with largely stochastic and strongly turbulent flow at SNL, over distinct but highly variable inter blade vortices (IBV) between SNL and about 50% power, over the draft tube rope in the 60 to 80% power range. Around the best efficiency point (BEP) the flow is generally smooth, but under some circumstances strong pressure pulsations can also occur just above and just below the BEP. Above the BEP, at high full and possibly overload, the full load rope can lead to pressure pulsations and power swings. All unsteady phenomena in hydraulic turbines are in one way or another related to the swirling nature of the flow.

We will present the current state of understanding of the causes of pressure pulsations across the full operating range of – primarily – fixed blade hydraulic turbines. This will be done based on model test observations and measurements, numerical simulations as well as some prototype measurements. Furthermore, we will show how this understanding and the related measurements and numerical simulations form the basis for the design of hydraulic turbines to be operated safely from 0-100% power. In this context, mitigation measures may be necessary such as well-known aeration or additional fins. Some examples will be presented.


Lessons learned from Comparisons Between Turbine Contractual Guarantees and Actual Field Performance Tests, presented by Albert Mikhail, KGS Group – HydroPower Performance Engineering Inc. (HPPE)

Turbine upgrade or new turbine design specifications requires to specifying performance contractual guarantees for turbine designers and manufacture.

It is always a challenge to write performance contractual guarantees that satisfy the following:
• Turbine deliver the target output and efficiency for the life of the turbine to have the highest ROI.
• The Performance Contractual Guarantees should be according to the unit actual 75% exceedance of the head and flow.
• Turbine modes of operation like base load, peaking plant, run of the river, etc.
• The Performance Contractual Guarantees should be achievable by turbine designer and manufacturer.
• The performance contractual guarantees should be measurable to be enforceable.
• Independent turbine performance tests should be the final measure to verify that the contractual guarantees were achieved.
This paper will present comparisons between the DB or turbine manufacturer contractual guarantees and actual performance tests conducted to verifying the turbine manufacturer delivered the committed performance, and lessons learned from these comparisons.

This paper presents 5 samples of comparisons for the following:
1. Turbines with output larger than 50 MW
2. Turbines with output between 20-50 MW
3. Turbines with output between 10-20 MW
4. Turbines with output between 5- 10 MW
5. Turbines with output less than 5 MW

The paper will present turbine designed fabricated according to actual to scale models and turbine designed and manufactured with CFD. It will display contractual guarantees from one point to 13 points for Francis, Fixed blades propellers, Kaplan and Pelton wheels.