**INDEX TEST ANALYSIS OF KAPLAN GENERATING
UNIT **

**Index Test at 69 Ft**

** **

ACTUATION TEST EQUIPMENT COMPANY

Winnebago, Illinois

January 14, 2016

**Introduction**

Performance
analysis of hydroelectric generating units can be done using a new Hybrid Index
Testing Method that does not require the test personnel to go to the dam. A large
part of the cost of index testing is the logistics of getting an expert test
crew (aka the expensive help) and their equipment on site for the index. Taking
advantage of modern powerplant SCADA systems, most of the necessary instrumentation
and a data logger are already in place.

This
is a report of our recent experience index testing a 5MW Kaplan in this way.

The
already extant powerplant data recorder was reprogrammed to add a few signal
channels and increase the sample rate to 2 Hz so that suitable data can be
continuously recorded en mass and then provided to Actuation Test Equipment Co,
Inc., (ATECo) for preliminary PostProcessing using the SteadyState algorithm in
the Index Test Box (ITB).

Upon
input to the ITB, the software program first sorts and converts the raw data
files to a compatible format for analysis. Affinity Law head corrections are
applied to the data in its rawest form, and then average values and two
accompanying “figure of merit” values are computed as described in the next
section.

These
results are then analyzed manually utilizing a test code specified methodology
to produce the overall efficiency profile and a new head-and-gate-to-blade cam
profile to load into the unit’s 3-D Cam.

Figure
1 Overall Unit Efficiency Profile

**Description of the Index Test Box**

The
Index Test Box is a standard IBM® PC Clone computer running any current version
of Microsoft Windows®. The ITB software is a Visual Basic 6 program compiled to
an executable-program for distribution. Distribution, installation, price and
operation are similar to a typical computer utility or video game program.

Using
the ITB, data can be acquired several ways:

1. Discreet
sensors can be used in powerplants without a SCADA system using National
Instruments® Analog/Digital Input/output boards and external I/O modules.

2. Data
can be acquired digitally from another instrument using any standard machine to
machine communication interface (OPC, IEE-488, RS-232 etc.)

3. Data
can be digitized and recorded by another test system, such as a typical
powerplant datalogger to record streamed data to files that are transported via
CDs, disks, flash drives or over the Internet.

ITB
Functions currently available include:

1. Stripchart-style
recording of live-field data for later analysis.

2. SteadyState
data analysis and collection of live field data.

3. Continuous
Efficiency Monitoring of machine health.

4. Digitization
of Cartesian coordinate charts of cam profile data

5. The
ITB was especially designed for index testing Kaplan turbines, but can also be
used to index test Francis, Pelton or any other type of turbines.

**Description of Data Reduction
Process**

Data
reduction takes place in several steps:

1. The input “raw-data” is the continuous strip-chart file from the
powerplant data logger.

2. The reduction process is
facilitated by rearranging the data columns of the raw-data file to conform to
the ITB input format and then truncated to cover just the 4-hour period during which the index-test data was collected.

3. The data is normalized in its “rawest” form as
it is read into the ITB for SteadyState analysis by applying the code specified[1] affinity laws to correct
for any head variations.

4. SteadyState points are gleaned from the
continuous raw-data file using a sliding 100-sample window to bracket a block
of data for statistical analysis.

5. This analysis consists of least-squares linear
regression computation of the 100-sample block that draws a line through the
“center of mass” of the 100-sample data block.

6. The center point of this line is the “Average
Value” for the data point and the slope of the line indicates its
“SteadyStateness.”

7. Next a Standard Deviation is computed between
each of the individual data points and the line to quantify data coherence.

8. To be deemed SteadyState, the slope of the line
must be near-zero and the standard deviation must be small.

9. An average value is deemed “steady-state” when
both Slope and Standard Deviation values are within operator pre-set limits.

Results of the
SteadyState analysis are output in three data file formats:

1. "AllData.csv" contains every analyzed data point.

2. “AllSSData.csv” contains only the “SteadyState” data points
that are deemed to be steady-state.

3. The third output is a set of files that are
named for the head, gate, blade, flow power and efficiency values of their
contents. For example, the file named “H683,_G953,_B686,_F8056,_P352,_E756,_SSData.csv” contains all data points at 68.3 ft head, 953
gate, 68.6 blade, 805.6 cfs flow, 3.52 MW and a generating efficiency of 75.6%.

For ease of evaluating
these results, data within all output files is arranged in chronological order.

The **AllData.csv** file is then analyzed further using the industry
accepted “smooth-curve” method to develop the new 3-D cam profile line for 69
feet head.

An accompanying overall
efficiency profile[2]
(that is essential to any Type-2 Optimization[3] scheme) is automatically
drawn by the ITB.

The **AllData.csv** file is a chronological list of SteadyState-filtered
ITB output data points with line breaks wherever a non-SteadyState point is
encountered. Averaged values for each column are the data set to go to the next
step in the analysis process.

The number of
consecutive identical test points is a figure-of-merit for the set of identical
data point - reasoning that *if* the
same value comes out many times in succession *then* the data point is steady-state and the average values are good
and stable.

The average value is at
the bottom of the head, gate, blade, flow, power and efficiency columns in each
data block.

In the next step the ITB
program consolidates these averaged values chronologically in the "**AllDataNew.csv**" file into the **"Results.csv"** file to create
a chronological listing of all of the averaged SteadyState points.

The final result of the
ITB SteadyState process is the **"Results.xlsx"**
file.

The data was sorted
again to remove any SteadyState points of less than 10 consecutive SteadyState
measurements, leaving only the longer, more steady-state dwells.

Next the steady-state
data points are sorted by blade angle, and then parsed at each blade
change.

Each block with equal
blade angles is next sorted by and gate stroke.

Average values are then
computed for each equal blade and gate block as the final output of the
SteadyState analysis routine.

A Cartesian coordinate
graph of this data set for the 2^{nd} index test at 48 feet gross head
shows this result (Figure 1).

Figure 2 Index Test Box Output results
for Dorena test data

CLASSICAL
SMOOTH-CURVE METHOD OF DEVELOPING INDEX TEST BEST-CAM PROFILES

Figure 3 Dorena Index Test Analysis Spreadsheet (Click image for spreadsheet download)

Figure
2 shows the layout of the data in the final spreadsheet.

In
a classical “fixed-blades, swept gates” index test, the blades are held at a
series of 5 or more fixed pitch angles while the wicket gates are positioned at
5 or more openings and then efficiency is measured by a code accepted method.

In
1984 DoE BPA’s Lee Sheldon provided a copy of USACE’s
tutorial on Kaplan index testing as a recipe of guiding principles, methods
and techniques to guide Woodward’s Index Test Box software development effort.

This
index testing manual is detailed, step-by-step instruction set that will allow
someone unfamiliar with Kaplan index testing to quickly get up to speed.

Lee
tells of the time when he was given several large boxes full of these manuals
as if they were not needed anymore; Lee grabbed a few and the rest of them got
lost.

Figure
3 shows an overview (the Big Picture) of the raw data from the powerplant data
logger with blade and gate positioning and computed gross unit efficiency.

Figure 4 Big Picture of index test points

At
each blade/gate pair test point, a 3-5 minute dwell is waited out to allow
everything to settle so that steady-state data points are assured.

Steady-state
data is assured because the analysis technique does not rely on “inefficient
carbon units” to establish and maintain steady-state operation for a known time
interval while supposedly steady-state data points can be captured and
recorded.

Instead,
the unblinking precision of the computer scans a continuous data stream for
steady-state operation and then captures and records a steady-state data point
whenever the unit happens to be running steady-state.

Added
confidence in the “steady-stateness” of the data is gained when a long,
contiguous series of data points is captured that have exactly the same values.

This
stream of readings is recorded for subsequent off-line ITB PostProcessor
SteadyState analysis that consists of a linear regression by least squares fit
and standard deviation for each blade/gate pair. These form a data set for
every individual fixed blade angle as shown by the blue highlighted tables in
Figure 2.

The
next step is to plot power and flow versus gate opening separately as two
"smooth curve" graphs, which are shown directly under each blue data
set as shown in Figure 2.

These
graphs are used to check for any random or precision errors in the data
sets.

All
of the data was very precise with no randomness evident.

Next
the data was recombined and the performance values computed for every 0.5% of
gate opening.

This
data is identified with pink highlight on Figure 2 and is plotted on the graph
entitled, "**Dorena 1 - Index Test Data Curves" **located at the far right of the spreadsheet
in Figure 2.

Figure
5 Final Graph of Classical Smooth
Curve Analysis Method

The
single data table highlighted in purple at the far left of the spreadsheet of
Figure 2 is the index test data input from the ITB software.

As
a double-check for this first index test, this data table was compared to hand
calculated results by plotting it right on top of the two 0-Degrees (flat-blade
angle) smooth curves to verify and demonstrate the coincidence of the ITB
software result with the industry accepted method’s result.

**Observations and Conclusions**

·
On the upper portion of the **Dorena 1
- Index Test Data Curves** graph a tangent line is drawn connecting the
tangents of the fixed blade profiles.

·
This graph shows the overall efficiency performance
of this machine at a gross head (forebay - tailwater) of 69 feet.

·
This means the intake losses, the
hydraulic losses in the penstock (friction and turbulence from sharp direction
and diameter changes) and the sudden expansion losses of the fluid exiting the
draft tube are all charged to the turbine.

·
This unit has a maximum efficiency of
76.7% at 2.9 MW where it is using 645 cfs.

·
The accuracy of an index test data
reduction can be judged by the lack of randomness in the line of interpolation points
on the lower portion of this main graph.

·
All of the data points fall on the
smooth curves which exemplifies the extreme accuracy with which this index test
data was reduced.

·
The tangent points of blade and gate are
plotted onto the lower graph and a line drawn through them to form the
"blade to gate cam curve."

·
Again, this data shows no randomness
whatsoever.

·
It does show the lift off point for the
blades at this gross head is 52.5% gate opening, which is a significantly large
gate opening, and that full steep blade angle is not achieved until
97.25%.

·
These two characteristics, along with
the low maximum efficiency (even when including the penstock losses) indicate
that design head or the head of best efficiency will be noticeably
higher. ** **

Sincerely,

Douglas Albright

End of file