MANUAL MEASUREMENT OF EFFECTIVE

PRESSURE, HEAD, FLOWRATE AND POWER

OUTPUT FOR EVALUATION OF EFFICIENCY OF

MICRO HYDRO POWER PLANTS

IN COLLABRATION WITH

AGA KHAN RURAL SUPPORT PROGRAMME

(AKRSP)

DR. JAVED AHMAD CHATTHA

GHULAM ISHAQ KHAN INSTITUTE OF TECHNOLOGY (GIKI)

TOPI PAKISTAN

November 2010

German Development Cooperation, Pakistan

Renewable Energy & Energy Efficiency REEE

House # 11-B, Street # 50, F-8/4, Islamabad Tel: 0092-51-2851175, Fax: 2854576

2

Table of Contents

INTRODUCTION: ..............................................................................................................................................4

1. Measurement of Effective Pressure Head using PV 350 PRESSURE TRANSDUCER MODULE....................5

Safety Precautions .............................................................................................................................................6

The PV350 Pressure Transducer Module ...........................................................................................................7

Pressure Measuring Sensor...........................................................................................................................7

Overview of the transducer ..........................................................................................................................7

Box Contents .................................................................................................................................................7

Procedure to Measure the Effective PRESSURE Head ........................................................................................8

Observations & Calculations ....................................................................................................................... 11

2. Measurement of Flow Rate Using UFM 610 FLOW METER....................................................................12

Introduction: ...............................................................................................................................................13

Safety Precautions ........................................................................................................................................... 13

Specifications of Equipment.............................................................................................................................14

Temperature indication/range:...................................................................................................................14

Fluid types: .................................................................................................................................................. 14

Pre-requisite for Flow-meter ......................................................................................................................14

Assumptions for Mounting the Transducer ................................................................................................14

Procedure to Measure the flow rate................................................................................................................15

Checklist: .....................................................................................................................................................19

Keypad Operations:..................................................................................................................................... 19

3. Measuring Power Output Using FLUKE 345 POWER CLAMP METER......................................................20

Introduction .....................................................................................................................................................21

Safety First ....................................................................................................................................................... 22

Some basics of power calculation ....................................................................................................................23

Reactive Power ........................................................................................................................................... 23

Real Power .................................................................................................................................................. 23

Apparent Power ..........................................................................................................................................23

Frequency....................................................................................................................................................23

Power Factor ...............................................................................................................................................24

Parts of the power clamp meter ......................................................................................................................25

Preliminary setting of the clamp meter ........................................................................................................... 26

Procedure for Taking Power readings..............................................................................................................27

Using single phase to measure power ........................................................................................................27

Using three phases to measure power .......................................................................................................28

Using the power quality clamp meter to take readings...................................................................................29

3

List of Figures

Figure 1-1 Plugging the PV350 ports into the DMM...............................................................................................8

Figure 1-2 Part of DMM – the pointer is set to mV.................................................................................................8

Figure 1-3 Showing Pressure/Vacuum Module.......................................................................................................9

Figure 1-4 DMM displaying zero.............................................................................................................................1

Figure 1-5 FLUKE PV 350 and DMM system is connected to selected hose/fitting by sensor. ...............................1

Figure 1-6 The DMM displays a reading in mV.......................................................................................................1

Figure 2-1 Location for attaching Transmitter to penstock for measuring Flow rate.............................................1

Figure 2-2 Use of chains to fix the transmitter .......................................................................................................1

Figure 2-3 Picture identifying the attachment point for transmitter on penstock..................................................1

Figure 2-4 UFM-610 Flow Meter.............................................................................................................................1

Figure 2-5 Diagonal position for Transmitters...................................................................................................... 20

Figure 3-1: power reading screen display ...............................................................................................................1

Figure 3-2 the wires coming out of the generator ..................................................................................................1

Figure 3-3 Parts of Clamp Meter...........................................................................................................................25

Figure 3-4: Press button to open and depress to close jaws................................................................................. 26

Figure 3-5 Insert red lead in the voltage slot and black lead in the ground slot.....................................................1

Figure 3-6 reading single phase power................................................................................................................. 27

Figure 3-7 Measuring power of the red phase........................................................................................................1

Figure 3-8 Knob setting for 3-phase .....................................................................................................................28

Figure 3-9: MEASURING three phase power.........................................................................................................28

Figure 3-10: gEnerator specification plate........................................................................................................... 29

Figure 3-11 Electronic Load Controller.................................................................................................................. 29

4

INTRODUCTION:

The formula for finding the efficiency of micro-hydro turbine is:

η = x100

Where:

P = mechanical power produced at the turbine shaft (Watts),

η = hydraulic efficiency of the turbine,

ρ = density of water (1000 kg/m3),

g = acceleration due to gravity (9.81 m/s2),

Q = volume flow rate passing through the turbine (m3/s),

H = effective pressure head of water across the turbine (m).

Density of water (ρ) and acceleration due to gravity (g) are constants. This manual

demonstrates the use of following three instruments to measure effective pressure head,

volume flow rate and power output for the calculation of efficiency of Micro-hydro Power

Plants.

1. PV 350 Pressure/ Vacuum Transducer Module

2. UFM 610 P FLOW METER

3. Power Quality Clamp meter

Note: Effective Head (H) is the net head available at the turbine inlet after accounting for fluid

friction losses in pipes

5

1. Measurement of

Effective Pressure Head

using PV 350

PRESSURE TRANSDUCER

MODULE

6

SAFETY PRECAUTIONS

• To avoid eye injury, always wear approved safety glasses when working with this

instrument.

• To avoid injury from pressure explosion: Be sure that pressure is removed before

disconnecting any hoses or tubing from the PV350 transducer. Follow accepted safety

procedures for systems on which pressure or vacuum measurements are made.

• Make sure the PV350 is serviced by a qualified technician.

• To ensure that the module is used safely, follow all safety and operating instructions in

this Instruction Sheet. If the module is not used as described in the Instruction Sheet, the

safety features of the module might be impaired.

• To avoid electrical shock disconnect the module from all devices before opening the

case. Be sure to completely reassemble the module before attempting to use it.

7

THE PV350 PRESSURE TRANSDUCER MODULE

PRESSURE MEASURING SENSOR

The PV350 Pressure Vacuum Transducer Module (the module) measures gauge pressure the

difference between atmospheric (barometric) pressure and the pressure (or vacuum)

applied to the pressure port on the transducer. It then converts that measurement to 1 mV

dc per unit. A module and a high-performance Digital Multimeter (DMM) with min/max

function become a data logger capable of measuring peak high and peak low.

OVERVIEW OF THE TRANSDUCER

• Compatible with all Fluke and most popular DMMs

• Digital pressure and vacuum measurements in a single module

• Transducer sealed in 316 stainless steel compatible with variety of liquids and gases

• Measures vacuum to 76 cm Hg

• Displays results in English (psig of Hg) or metric (kPa or cm Hg) units

• Measures pressure to 3447 kPa (500 psig)

BOX CONTENTS

Within the pressure transducer box, you will find:

• Pressure/Vacuum Transducer Module

• 1/4 in. male flare to 1/4 in. female pipe thread connector

• 9 V battery

• Instruction Sheet

• Quick Reference Guide

8

PROCEDURE TO MEASURE THE EFFECTIVE HEAD

Step 1: Plugging PV350 ports into the Digital Multimeter (DMM)

Plug the red PV350 port into the DMM (red polarity dot to volts input) and the black port of

the Pressure Transducer Module into the black (COM) plug-in point on DMM [Fig. 1].

Step 2: Setting the knob to mV

After plugging the PV350 ports into DMM, set the multimeter knob on milliVolts dc

[Fig. 1.2].

Step 3: Testing of Battery

Connect the PV 350 Pressure/Vacuum Transducer Module to DMM and get the reading at

mV scale. If the reading is less than 100 mV then battery change is required (see the

equipment manual for details).

Insertion of PV350

ports into DMM

Figure 1-2 Part of DMM – the pointer is set to mV

Figure 1-1 Plugging the PV350 ports into the DMM

9

Step 4: Selection of System of Units

Press the English/Metric button on PV350 Pressure transducer to select the desired units

[Figure 3]. In Metric system, reading will be in mV.

Sliding knob on the module is used to get the desired setting [Figure 1.3]. The pointer is

placed at mV to obtain readings. Metric system is preferred since conversion from DMM

readings to head in meters is simple.

Step 5: Zeroing the Pressure Transducer Module

Before applying pressure, zero the module by turning the ZERO potentiometer until the

DMM displays zero [Figure 4]. Re-zero the DMM whenever the scale is changed. This is done

to make sure that the DMM always displays zero (0) prior to taking a reading, as shown in

Fig. 1.4.

Red Port is inserted in

the red (V Ω) plug-in

point on DMM

The black port is

inserted in the black

(COM) plug-in point on

DMM

The button is pressed

to adjust the unit

system- METRIC or

ENGLISH

Slider- It is adjusted according

to required units and unit

system. The two systems are

shown

The ZERO button is

turned to adjust

initial reading on

DMM to 0.

Transducer is further

connected to area of

turbine where pressure is

to be measured

Figure 1-3 Showing Pressure/Vacuum Module

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Step 6: Purging of air

Before mounting the PV350 transducer on the inlet pipe, open the valve to vent out that air

trapped inside the pipe. Also, Teflon sealing tape (or its equivalent) should be used in fitting

threads to ensure good seals between the PV350 and any hoses or fittings. The instrument

is now ready for the reading.

Step 7: Connecting the Pressure Sensor to the Pressure valve

Apply pressure to the PV350 transducer by inserting the sensor into the pressure input point

on the inlet pipe of the turbine (Figure 1.5) and read the DMM display. When measuring

pressure, if the DMM display’s ‘OL’ (Open-loop is a condition in which no current flows due

to infinite resistance. Hence no voltage exists across its probes’ end), switch the multi-meter

range from millivolts (mV) to dc volts. Increasing the range to dc volts moves the decimal

position three places to the left (500 mV displays as 0.500 V). Also, Teflon sealing tape (or its

equivalent) should be used in fitting threads to ensure good seals between the PV350 and

any hoses or fittings. The instrument is now ready for the reading and display the reading as

shown in Fig. 1.6

Figure 1-4 DMM displaying zero

Figure 1-5 FLUKE PV 350 and DMM system is connected to selected hose/fitting by sensor.

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OBSERVATIONS & CALCULATIONS

The practical use of PV350 Pressure/Vacuum Transducer Module is to measure gauge

pressure at a point as indicated in [Fig. 1.6], which can be further converted to Pressure

Head (m) at that point. DMM displays the reading in mV which is calibrated as:

1mV = 1 kilo-Pascal (kPa)

Hence the reading displayed is in equivalent kilo-Pascals (kPa) which can further be

converted into Effective Pressure Head (m) by the following conversion factor:

1 kPa = o.1 m of H2O

1 m of H2O = 10 kPa

Example:

The reading displayed on the [Fig. 6] is 225.9 mV which is equivalent to 225.9 kPa.

Applying the conversion factor: 10kPa = 1m of H2O. The effective Pressure Head at

this point can be calculated as: 225.9/10 = 22.59 m of H2O.

Figure 1-6 The DMM displays a reading in mV

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2. Measurement of

Flow Rate

Using UFM 610

FLOW METER

13

INTRODUCTION:

A flow meter is generally a device used to measure the flow of a fluid.

The UFM 610 P is a portable flow meter designed for use on liquid flows in full pipes. The UFM 610

P has an easy to read Graphics Display. This Flow Meter Manual has been specially designed to

facilitate the users determining volumetric flow, velocity etc for Micro-hydro Power Plants.

The flow meter comes in an easy to carry case with the other following equipments; ensure that

these are present before actually setting-up the meter:

• Transmitter Module

• Receiver Module

• Conducting Gel

• Chains

• Connecting wires

• Meter Battery Charger

SAFETY PRECAUTIONS

• Avoid any contact of the gel with your eyes and excessive contact with your skin.

Use syringe and gloves to apply and spread gel, respectively.

• Rinse thoroughly with plenty of water if it comes into contact with eyes and

consult a doctor.

• Do not turn the knurly knobs forcefully lest they make strong contact with pipe

surface. Only finger tight contact is enough.

14

SPECIFICATIONS OF EQUIPMENT

TEMPERATURE INDICATION/RANGE:

The transducers work over two temperature ranges. The standard temperature range is from-20 0C to +100

0C and high temperature is from –20

0C to +200

0C. The application temperature is

displayed when in flow mode only if the prop/temp sensor cable is connected.

FLUID TYPES:

The types of fluids that can be measured with the UFM 610 P are clean liquids or oils etc that have

less than 3% by volume of particulate content. Liquids that are cloudy, like river water, effluent

etc. can be measured and also liquids that are clean, like demineralised water. During the set up

procedure the user is asked to select from a list of liquids (See fluid list table below) which

includes water and oils. If the liquid to be measured is not listed it is possible for the instrument to

measure the propagation rate automatically, but only when pipes sizes are greater than 40 mm

internal diameter.

Applications include: - River water, Seawater, Potable water, De-mineralized water, Treated

effluent, Water/Glycol systems, Hydraulic systems and Diesel oil.

PRE-REQUISITE FOR FLOW-METER

These are the things that you should know before operating the flow meter.

• Pipe outer diameter

• Pipe wall thickness

• Material which pipe is made off

If you do not know these things flow meter is not able to give you the required reading.

ASSUMPTIONS FOR MOUNTING THE TRANSDUCER

As the transducers for the UFM 610 P are clamped to the outside surface of the pipe, the meter

has no way of determining exactly what is happening to the liquid. The assumption therefore has

to be made that the liquid is flowing uniformly along the pipe either under fully turbulent

conditions or under laminar flow conditions. Further it is assumed that the flow velocity profile is

uniform for 3600 around the pipe axis. To ensure a uniform profile the transducers must be

mounted far enough away from any cause of distortion such that it no longer has an effect.

Water

Glycol/water 50/50 Lubricating oil Diesel oil Freon Measure

15

PROCEDURE TO MEASURE THE FLOW RATE

1. First measure the circumference of the penstock pipe manually and calculate its

diameter.

2. Compare the calculated diameter with the actual diameter. If the reading is a slight

difference then this difference is due to the painting, rusting etc in the manual reading.

3. Place the ultrasound transmitter on the pipe inclined as shown in [Fig. 2.1]. It is of

utmost importance that the ultrasound transmitters should be attached to the pipe in

an inclined manner as shown in the [Fig. 2.1] (location 2) so that the device truly

measures the flow at low flow rates i.e. when the pipe is half filled.

4. Get hold of the ultrasound transmitter (which is the longer module) and put it against

the penstock-pipe from which flow reading has to be taken.

5. Once you have determined the appropriate position (on penstock) to place the

transmitter, mark that position (using a marker). Apply a small amount of gel on the

transmitter module under the transmitter part. Spread the gel so as to form an even

layer of suitable thickness. Also apply a fine layer of gel on the penstock in the previously

marked area. The layer of gel is the critical thing in receiving the signals from the

transmitter so application of an even and suitable layer of gel is necessary.

Figure 2-1 Location for attaching Transmitter to penstock for measuring Flow rate

16

6. Place the transmitter and use a chain [Fig. 2.2] to fix it in proper place. Clamp one end of

the chain of the module and make it go one rotation around the pipe and then, clamp

the free chain end to the other chain link on the module. Screws like ends are available

on the modules to tighten the chains. Don’t make it too tight just yet since it will have to

be adjusted time and again. Also you will need two or three people for performing this

procedure.

7. It should be of due importance that the sensor set is touching the surface of the pipe.

This can be ensure by seeing the [Fig. 2.3] as the two points are touching the pipe, if

these two points are touching the surface then in turn the sensor is also touching the

surface.

Figure 2-2 Use of chains to fix the transmitter

Figure 2-3 Picture identifying the attachment point for transmitter on penstock

17

8. Next, connect the black, blue and red wires to the module, and into the appropriate

colored parts on the meter as shown in Fig. 2.4.

9. Turn on the meter using the ON/OFF button.

10. Follow the on screen instructions which are simple to comprehend. The meter will ask

you for simple details such as penstock length, pipe outer diameter, pipe wall thickness,

material which pipe is made off etc. Simply enter the values as they are asked. No need

to enter the inner diameter.

11. Next, the meter will display the most important piece of information needed to setup

the transmitter and receiver. It will tell you in which position to place the

transmitter/receiver, and what should be the distance between the transmitting part

and the receiving part.

12. The meter is going to advise you about positioning of the module either in a diagonal

way or reflex (both methods are different as far as the positioning is considered).

There are two positions, depending on the outer diameter of the pipe:

I. The transmitter and receiver are place diagonally across the pipe if its diameter is

generally large (more than 300 mm). This position is termed “diagonal” by the

meter [Figure 2.5].

II. The transmitter and receiver are placed in a straight line if the pipe diameter is

small (less than 300 mm). This position is termed as “reflex” by the meter.

Figure 2-4 UFM-610 Flow Meter

18

13. Usually though the diameter is large enough that the diagonal position will be used. The

meter will tell you the most suitable position to use, in the given circumstances. Once

the transmitter and receiver have been clamped, set the separation distance indicated

by the meter.

I. If the “reflex” mode is being used this pertains to the distance between the end of

the fixed transducer (transmitter) and the beginning of the floating transducer

(receiver).

II. If “diagonal” mode is selected, the separation distance is fixed as the distance from

the ending of the off-white plate (transmitting part), then moving along the

calibration by an amount equal to the separation distance and then going around the

pipe, and that spot on the receiver. The off-white plate on the receiver should start

from this point.

14. Connect the red lead into the receiver module and also in the meter. The red cable

indicates positive flow if upstream.

15. Now turn the knurled knobs anti-clockwise, until in finger tight contact with the pipe

surface.

16. After taking various readings at different flow rate, tabulate the results in prescribed

manner; then carefully disconnect and unclamp the instruments, and put them back in

their appropriate place.

Diagonal Position

Figure 2-5 Diagonal position for Transmitters

19

CHECKLIST:

Check the meter to see signal strength. It should be around 80% to give a good reliable

reading. Sometimes it can give an appreciable reading at 50% signal strength. To make sure,

check the velocity (of the fluid) by pressing Button 4, and check whether this velocity

reading corresponds to the velocity specified on the turbine specification plate or if it’s

around 2.5-4 m/s. If this is so then the flow rate reading is probably correct. Try to vary the

signal strength, and see if flow rate reading fluctuates to be sure of the accuracy of the

obtained reading.

KEYPAD OPERATIONS:

By selecting keys 4, 7, 8 and 9 it is possible to change the velocity and volumetric flow

readings. Press the key more than once to change the display into other units. To move the

cursor on the display left and right as well up and down press keys 5 (left) and 6 (right).

The meter also displays the temperature of the fluid flowing through the pipe.

20

3. Measuring

Power Output

Using FLUKE 345 POWER

CLAMP METER

21

INTRODUCTION

FLUKE’s Power Quality Clamp Meter is like a standard Digital Multimeter (DMM), except

with slightly enhanced functions. This manual shows you the correct way of using the Clamp

Meter and to ensure that you get accurate results from your measurements and that you

interpret them correctly.

Fluke’s345 is more than an electric power meter. Combining the functions of a clamp meter,

oscilloscope, data logger and digital power meter into one handy device. The Fluke 345 is

ideal for working with variable frequency motor drives, high efficiency lighting and other

loads using switching electronics.

As can be seen in the Fig. 3-1, the power clamp meter can measure seven distinct

parameters in a power line without the need to break the circuit. Because the circuit does

not need to be broken, a clamp meter not only is safer than a standard multimeter but also

allows much quicker testing.

These parameters along with the units in which they are measured are:

• Real power, kW

• Apparent power, kVA

• Reactive power, kVAR

• Voltage, Vrms

• Current, Arms

• Power Factor

• Frequency, Hz

Figure 3-1: power reading screen display

22

SAFETY FIRST

Always wear safety gloves (rubber gloves) when handling electrical equipment and working

with electrical wires.

Wear rubber boots when working with high voltages.

Never touch bare wires or even well insulated wires with your bare hands.

Remember in the case of rescuing someone from an electrical shock; always use an insulator

such as a piece of wood to pull that person away from danger.

Be extra careful of your surroundings when working in areas where high voltages are

involved.

When using the clamp meter, make sure that two wires don’t accidentally come into

contact thus creating short-circuit. This can give you a shock or even start an electric fire.

Take care of yourself and those working around you.

23

SOME BASICS OF POWER CALCULATION

Electric power is the rate at which electrical energy is transferred by an electric circuit. The

SI unit of power is the watt. In its most basic form, electrical power is the product of current

and voltage

P = VI

REACTIVE POWER

Reactive Power is power stored in and discharged by inductive motors, transformers and

solenoids. It is measured in volt-amperes reactive (VAR).

REAL POWER

The actual amount of power being used, or dissipated, in a circuit is called Real power, and it

is measured in watts

APPARENT POWER

The combination of reactive power and Real power is called apparent power, and it is the

product of a circuit's voltage and current, without reference to phase angle. Apparent

power is measured in the unit of Volt-Amps (VA)

FREQUENCY

Another important parameter that appears quite often in electrical quantities is Frequency,

measured in HERTZ (Hz).It is the number of cycles that a waveform completes in one second.

Note: The typical frequency of distributed electricity in Pakistan is 50 Hz.

RMS or root-mean-square value is the effective or average value of a quantity such as

current or voltage. It is obtained by squaring the desired quantity over a given time interval,

taking its average and then taking its square root.

So we define the effective or RMS value of a periodic current as a constant or dc value,

which as current would deliver the same average power to a given load.

24

POWER FACTOR

Power factor is best described as the ratio of the active power to the total power in the

circuit. As shown in the figure below, total power is a vector sum of active and reactive

power. Power factor is mathematically equal to the cosine of phase angle o between the

voltage and the current wave forms. The power factor relationship and terms are

summarized below.

The following formulas are derived from the vector relationships shown in the diagram

above:

(kVA)2 = (kW)

2 + (kVAr)

2

There are three phases coming out of the generator and going into the distribution box.

These are the Live, Neutral and the Earth phase.

Power is transmitted through these three phases and a fourth wire along these is also used

which is the ground wire, relative to which all measurements are taken.

The color codes as used in Pakistan are:

Red: Live

Blue: Neutral

Yellow/Green: Earth

Black: Ground

Figure 3-2 the wires coming out of the generator

25

PARTS OF THE POWER CLAMP METER

Figure 3-3 Parts of Clamp Meter

Clamping Jaws

LED Back-lit

Display

“W”-Single phase

power reading

“W3φ”- three phase

power reading for

balanced load

Off position

Voltage “V”

Current “A”

Press to open and

release to close jaws

Terminal to insert black

lead

Terminal to insert red

lead

26

PRELIMINARY SETTING OF THE CLAMP METER

1. The power clamp meter is a simple instrument to operate. As shown in Fig. 3-4, use

the red button located on the left side of the meter to open and close the clamping

jaws.

2. To clamp the meter around a wire, press the button till the jaws open and then place

the open jaws around the wire. Release the button to close the jaws.

3. To take out the meter, again press the button till the jaws open and then carefully

remove the meter from around the wire. Releasing the button will again close the

jaws.

Figure 3-4: Press button to open and depress to close jaws

There are two leads provided with the power clamp meter, one red and one black.

4. The red lead is for positive and the black one is for common or ground.

5. Insert the red lead into the slot with the symbol V orΩΩΩΩ, as shown in Fig. 3.5.This is

used to measure positive voltage.

6. Insert the black lead into the slot with the symbol , also shown in the Fig. 3-5.

This is used as a reference voltage or ground potential.

7. These leads when placed on metallic contacts will read the voltage across the two

points. This will be explained in detail later.

8. The picture below shows the correct method of inserting the leads into the meter

.

Figure 3-5 Insert red lead in the voltage slot and black lead in the ground slot

27

PROCEDURE FOR TAKING POWER READINGS

USING SINGLE PHASE TO MEASURE POWER

1. Set the knob on the dial to W to read single phase power, as shown in Fig. 3-6. The

meter display will be identical to that of Fig. 3-5.

Figure 3-6 reading single phase power

2. Clamp the jaws of the meter around the phase (wire) whose power is to be

measured and then using the probes; place the read lead on the metallic contact of that

particular phase and the black lead on the metallic contact of the black (ground) wire

[Fig 3-7].

3. This will display the power readings on the screen.

4. Follow the same procedure for the other two phases by clamping the meter around

the wire whose power is to be measured and then using the probes to put the red

lead on that phase and the black lead on the other phase. Complete readings of

power measurement for all these phases in this way.

5. To find the total power being consumed by the load, simply add up the kW readings

for all three phases i.e.

Total Power = kW red + kW blue + kW yellow

6. To find the total power output of the generator, add up all the kVA readings (kVA is

the measure of apparent power of the system).

Figure 3-7 Measuring power of the red phase

28

USING THREE PHASES TO MEASURE POWER

Power can also be measured using the three-phase option of the power clamp

meter. This can only be done for the case when the power on the three phases is

balanced.

1. Switch the knob to W3ф mode of the power clamp meter. Switch the meter to this

mode as shown in the Fig. 3-8.

Figure 3-8 Knob setting for 3-phase

2. Clamp the meter to any one phase, let’s say the red phase and put the probes on the

metallic contacts of the other two phases. This is shown in the diagram below. The

meter will display the total power being consumed by the load in kW and the total

power being supplied by the generator in kVA.

Figure 3-9: Measuring three phase power

29

USING THE POWER QUALITY CLAMP METER TO TAKE

READINGS First read off the maximum power that the generator can produce. This is the upper limit

and the first reading has to be taken at this value. This is referred to a full load.

All readings following this have to be taken at 10% decreasing load by turning the guide

vane of the turbine to decrease the flow. This will in turn reduce the frequency but the

frequency has to be adjusted back to 50Hz. This value of frequency should be used when

taking all the readings.

The frequency can be adjusted using the Electronic Load Controller (if installed) or by using

the hydraulic governors. There are special knobs on the load controller which can be used to

regulate the frequency.

Figure 3-10: Generator specification plate

Figure 3-11 Electronic Load Controller