▪ Abstract Conventional hydroelectric generation uses a renewable energy source and currently supplies ∼10% of the annual output of electricity in the United States and ∼20% of electricity generated worldwide. To provide a significant contribution to sustainable development, the hydropower industry must address a variety of environmental concerns, including water quality and fish passage issues. The paper discusses new technologies for turbine design and control systems to improve dissolved oxygen levels in turbine discharges and survival of fish during turbine passage. The paper describes development, testing, and test results for these technologies, with an emphasis on collaboration of stakeholders and balance between environmental stewardship and economical power production.

The sliding gate technique for efficiency testing of hydroturbines is described in the article. In the method, the wicket gates are advanced slowly and continuously throughout the test range while continuous data for efficiency calculations are acquired relatively quickly. The advantages of the method include reduced testing time, a more complete definition of the efficiency curve, and increased accuracy. Procedures for conducting the test, including special requirements for Kaplan units, are given. Efficiency tests and results for several hydro units are also described.

Increasing the dissolved oxygen levels in water discharged from hydroelectric stations is a significant challenge. Research and development on re-aerating turbines promising to provide effective solutions.

A computer-assisted system for performing index test on hydroturbines is described. This system allows for more rapid and accurate index testing of hydroturbines than has previously been available. The system software and hardware are described, sample results are presented, and future developments are outlined.

This paper presents a methodology for computing analyses and indicators to track and maximize the benefits of a hydroturbine testing program and describes techniques for unit testing to minimize testing costs. On-line measurements of unit power, headwater, and tailwater can be used in conjunction with unit characteristics to quantify the energy and revenue losses associated with non-optimized plant dispatch. With the addition of an on-line flow measurement, differences between the expected and measured unit characteristics can be computed, thereby providing an overview of the accuracy of the unit characteristics. Representative examples are presented for several plants. A similar approach can be used to structure a comprehensive test program for a hydro utility or agency. Background The following discussion presents the components for structuring and tracking a hydroturbine testing program. The initial assessment of a hydro system requires archival data containing individual unit power data, headwater, tailwater, and the unit characteristics that are being used to determine the unit dispatch. With these data, multiple analyses can be performed, including: (1) operation efficiency analyses; (2) sensitivity analyses to evaluate the energy and revenue losses that errors in the unit characteristics would produce; (3) scheduling efficiency analyses; and, with the addition of a real-time flow measurement for each unit, (4) correlation efficiency analyses.

Performance tests were conducted on Unit 1 at the Tennessee Valley Authority's Fort Patrick Henry Plant on September 24 - 25, 1997. These tests included measurements of the discharge through the turbine using current meters and the Acoustic Scintillation Flowmeter (ASFM). Fort Patrick Henry is a low-head, short intake plant typical of the type for which current meters have been the traditional and only effective method for measuring discharge. Unit 1 is rated at 21 megawatts and is equipped with a Kaplan turbine. The intake to the turbine consists of two bays, each 21.65 ft high and 17.67 ft wide. The net head for the plant is approximately 65 ft. Measurements of the discharge through the turbine were made at two power levels: the Most Efficient Load (MEL) and the Maximum Sustainable Load (MSL). The ASFM is a new instrument which offers some unique advantages for measuring intake flows in plants of this type. It is non-intrusive, and its deployment in intake gate slots is straightforward, allowing data to be collected with a minimum of plant down-time. The measurements described here were taken to assess the ASFM's accuracy under operational conditions. Flow measurements at the same unit settings were made using current meters operated by the Norris Engineering Laboratory, for comparison with the ASFM results. The ASFM and current meter measurements were made sequentially. Immediately following data collection discharges were computed independently and then compared. These results for both techniques agreed to within 1%, after correction for small head differences between the measurements.