Unless otnerwise provided, head losses between tile high-pressure and low-pressure sections are charged to the machine. Other head losses including those due to conduits upstream and/or downstream of the machine intakes, trashracks, gates, valves and the discharge velocity head loss at the conduit exits shall not be charged to the turbine or credited to the pump.
At installations where an absolute flow rate measurement is not practical or desirable, the index method (paras. 4G.1 through 4G.18) may be used. Index testing makes use of the relative flow rate in order to determine relative machine efficiency.
In the case of a machine with both adjustable wicket gates and adjustable runner blades, index testing should be carried out before the performance test to determine the best gate and blade combination. The positions of the wicket gates and runner blades for various positions of the operating mechanisms shall be accurately measured and suitable reference scales provided. These scales shall be accessible during operation and their indications shall be recorded during the test.
For pumped storage installations, with small reservoirs, tests can be conducted conveniently over the entire operating head range. One or more runs at the various gate openings shall be conducted at each of several heads, using machined metal spacers, if necessary, for accurately and positively blocking the gate servomotors at each position.
For pumped storage installations with large reservoirs it may be convenient to conduct tests at only one point in the head range. At each constant head, sufficient test runs shall be conducted at the same gate opening using metal spacers, if necessary, to reduce the positioning error.
Preliminary test runs complete with records and calculations shall be conducted to ensure that the equipment, instrumentation, personnel, and procedures are functioning properly. Any problems shall be corrected prior to proceeding with the official test. If agreeable to the Parties to the Test, preliminary runs may be considered to be official runs.
True copies of all official test data taken manually or electronically, test logs, notes, sample calculations,results, and plots along with pre-test instrument calibrations shall be provided to the Parties to the Test prior to the dismantling of the test instrumentation or departure of the test group from the site. Programs that are used to calculate results may be considered as proprietary. However, sufficient information needs to be provided for the true copies which permits the duplicated data to be used to calculate the test results. These copies will provide the Parties to the Test with all information plus ensure the safekeeping and integrity of the test data.
Preliminary results shall be computed during the course of the test and these results, together with selected important measurements, shall be plotted on graphs. Any run which appears to be inconsistent with the other runs or appears to exceed limits of deviation or fluctuation shall be repeated. However, test records of all runs shall be retained.
Every reasonable effort shall be made to conduct the test as close as possible to specified operating conditions in order to minimize deviation corrections. Each run shall be conducted under the best steady state conditions obtainable at the operating point. Once a test has started, adjustments to the equipment under test or the test equipment, which may affect test results, shall not be permitted. Should adjustments be deemed necessary by the Parties to the Test, prior runs shall he voided and the test restarted.
Test runs should be made under conditions of constant speed, constant head and constant power within the following limits of variation during an individual run:
(a) Variations in measured speed should not exceed ±0.5% of the average speed measured.
(b) Variations in measured head should not exceed ±1.0% of the average head measured.
(c) Variations in measured power output or input should not exceed ±1.5% of the average measured power.
Should the actual average conditions of any test deviate from the corresponding specified conditions, they shall be treated individually as follows.