The paper objective is to design an experimental stand for a water
turbine assembly, which allows the monitoring of the input and output
parameters in order to identify its performances. The stand is equipped
with an interface with the computer that allows developing a data basis
of input and output speeds and moments. The testing on the experimental
stand is the first step in the development of the small hydro control
system in real functioning conditions
The turbine assembly consists of a Turgo turbine, a planetary speed
increaser with deformable element that was proposed by the authors
(Jaliu, 2009) and a generator. The model of the turbine assembly is made
using CATIA and INVENTOR software.
2. THE 3D MODEL OF THE TURBINE ASSEMBLY
The 3D model of the Turgo turbine assembly that is proposed to be
implemented on a river near Brasov is presented in Fig. 1, a. The
assembly consists of the Turgo turbine that was acquisited in the frame
of a research project,, a planetary chain speed increaser (Fig. 1,b) and
an electric generator. The speed increaser consists of a chain
transmission and three parallel connecting rods with bearings (Fig. 1,b)
and is proposed by the authors. The transmission is manufactured and
will be assembled between the turbine and the generator through two
3. EXPERIMENTAL STAND
In the design of the control system, the following premises were
considered (Harvey, 2005, Von Schon, 2007):
* the water turbine is designed for particular values of the water
head and flow. Any perturbations of the small hydro input and output
parameters has to be compensated by the control system that, closes /
opens a valve to maintain the water level in the basin or a constant
output power, starts or stops the small hydropower plant.
* The system allows monitoring the input and output parameters for
the assembly and, also, for the speed increaser. Thus, the stand control
system has to:
a) Detect the input and output parameters;
[FIGURE 1 OMITTED]
b) Maintain the parameters within the limits admitted by the
c) Take decision automatically regarding the system start, stop and
d) Colect the data necessary in taking operational decisions;
e) Function in an unattended environment, at maximum working
f) Have remote acces.
In the experimental stand, the turbine assembly is used to produce
electricity to supply a water heater of 25 l (Fig. 2). An electro-valve
is used to control the water flow on the turbine and six sensors are
used for monitoring the input and output parameters.
[FIGURE 2 OMITTED]
The proposed system acquires analogic values of 8 parameters:
temperature, voltage, input moment and speed, and output moment and
speed, water pressure and flow. The moment sensors include the speed
sensor, which gives an impulse for each rotation. The speed is then
computed by the PLC software.
The software for data acquisition exports the values to a text file
(see Fig. 2).The stand controls the temperature in the boiler, so that
the electro-valve is closed and, thus, the turbine is stopped when the
water temperature is increasing above a predefined value (900).
An experimental stand was designed by the authors to allow
monitoring the input and output parameters of a water turbine assembly
and identify its performances. The speed increaser that is part of the
assembly is an innovative solution proposed by the authors (Jaliu,
2009). The following aspects can be highlighted from the turbine
1) If the generator load decreases, the turbine tends to increase
its speed; by means of a sensor to measure the frequency, control system
must enter the preset circuit resistance, thus maintaining the current
2) Usually, micro-hydropower systems use to regulate output power,
electronic devices ELC (electronic load controller) (Davis, 2003). The
controller automatically compensates any change in load by changing the
amount of power dissipated in a resistive load, called ballast load,
thus maintaining the overall tasks of the generator and turbine
constant. In general, electric water heater is used as ballast. ELC are
usually used with synchronous generators.
3) One of the test programs on the experimental stand is meant to
determine the system's electrical response. This
involves determining the electrical and hydraulic powers depending
on the sensors measurements; thus, the conversion efficiency of the
operation in the representative situations can be established. The
efficiency of the Turgo assembly: turbinespeed increaser-generator is
then compared to the efficiency of the turbine-generator system. This
comparison highlights the influence of the speed increaser on the
energetic response of the global system.
4) The Turgo assembly is also tested in order to identify its
performances for different values of the input parameters (water flow).
The study allows identifying the limits within which the system operates
in good conditions.
The monitored data will be compared to the numerical simulation
results (Jaliu, 2010) in order to validate the theoretical model of
speed increaser. The testing results are also useful in the design of
the control system for the micro hydropower plant that will be
implemented on Poarta River, near Brasov.
Harvey, A. (2005), Micro-hydro design manual, TDG Publishing House
Von Schon, H.A.E.C. (2007), Hydro-Electric Practice--A Practical
Manual of The Development of Water, Its Conversion To Electric Energy,
And Its Distant Transmission, France Press
Jaliu, C., et al (2009), Conceptual design of a chain speed
increaser for small hydropower stations. Proc. of the ASME IDETC/CIE
2009, San Diego, California, USA, CD Proceedings, ISBN:
Jaliu, C., et al (2010), Dynamic Model of a Small Hydropower Plant.
OPTIM 2010. Proc. of the 12th International Conf. on Optimization of
Electrical and Electronic Equipment. May 20-21.10, Brasov, pp. 1216-1223
Davis, S. (2003), Microhydro: Clean Power from Water, New Society