LABORATORY MODULES ELECTRICAL MEASUREMENT · Measurement Lab. 10 IV. EXPERIMENT PROCEDURE 1. ... Then measure the components using RLC Meter. 5. ... Q à in VAR, reactive power V

LABORATORY MODULES

ELECTRICAL MEASUREMENT

ELECTRICAL ENGINEERING DEPARTMENT

FACULTY OF ENGINEERING

UNIVERSITAS INDONESIA

2018

HIGH VOLTAGE AND ELECTRICAL MEASUREMENT LABORATORY

ELECTRICALMEASUREMENTLABORATORYMODULES2018

HighVoltage&ElectricalMeasurementLab.

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MODULE 1

LABORATORY BRIEFING AND PRE-TEST

Laboratory Breifing is held on February 19, 2018 at 18.45 PM located at K building,

K301, Faculty of Engineering. Attendance to briefing and pre-test is mandatory and will be

included in the scoring system.



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MODULE 2

IMPEDANCE MEASUREMENT

I. OBJECTIVE

1. To know LCR Meter and its function

2. To know the construction of LCR Meter and how LCR Meter works

II. BASIC THEORY

LCR meter is an electronic electrical measurement to measure resistance,

inductance and capacitance value. The utilization is relatively easy since today, a digital

LCR meter is already in the market, and it makes the user easier to use it. Here is a brief

explanation about resistor, inductor and capacitor

Resistor is an electronic component that has the function to control and limit

electricity. It is also used to limit the amount of current flowing in a circuit. According to

its name, resistor is resistive and mostly is made from carbon. The unit of resistance is

Ohm and symbolized by omega. Type of resistors mostly has the shape of tube with two

copper legs. There are colored circles in the body to make the user know about the

resistance without measuring it using measurement device. (example: ohm meter)

Figure 1. Resistors types

Inductor is symbolized by L. Usually in a form of coil, but sometimes has other

forms too. Inductor or coil is one of passive components that is made up by coils and

usually save up energy in form of magnetic field. The unit for inductance is called Henry



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(H=Henry, mH = millihenry, etc). An inductor is called as ideal if it has inductance, but

has no resistance or capacitance and does not waste much energy.

Figure 2. Inductors Types

Capacitor is an electronic component that can store electric charge in a certain

time. The definition of capacitor is electronic component that save electrical current

charge in electric field until a certain time by collecting internal inequity from electric

current charge. Capacitor was invented by Michael Faraday (1791-1867). The unit of

capacitance is Farad (F). One farad is equal to 9×1011 cm2.

Figure 3. Capacitors Types

LCR Meter is a part of electronic measurement device to measure inductance (L),

capacitance (C) and resistance (R) in component. In the simpler form of this device, the

real value of these units is not measured; so that impedance will be measured internally

and converted to be shown to capacitance that match or inductance value. The reading

will be pretty accurate if capacitor and inductor of device tested do not have impedance

significant resistive component.



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The basic resistor measurement principle with LCR-740 is WHEATSTONE

bridge. Wheatstone bridge is an electrical circuit consisting of two parallel circuit

branches connected with the galvanometer with the aim to measure an unknown electrical

load. Wheatstone bridge has four rsistance arms, a source and a detector, usually in the

form of galvanometer. Wheatstone bridge can be used to determine the unknown

resistance value, for example (see figure 4), suppose R4, we determine the value of the

resistor until current through the galvanometer indicates the the value of zero. Wheatstone

brigde is said to be in equilibrium if the voltage delta in galvanometer is zero volt, in this

case there is no current flowing through galvanometer. At Figure 4, I of Wheatstone

bridge will happen if voltage at C to A is equal to voltage from D to A, or if voltage from

C to B is equal to D to B. In this case:

Figure 4. Wheatstone bridge

I1 R1 = I 2 R 2............................................................... ( 1-1 )

If galvanometer shows zero, hence:

𝐼! = 𝐼! =𝐸

𝑅! + 𝑅!. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ( 1 – 2 )

𝐼! = 𝐼! =𝐸

𝑅! + 𝑅!. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ( 1 – 3 )

By substituting equation (1-1),(1-2) and (1-3), we have: 𝐼!𝐼!=𝐸/(𝑅! + 𝑅!)𝐸/(𝑅! + 𝑅!)



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𝐼!𝐼!=𝑅! + 𝑅!𝑅! + 𝑅!

𝐼!(𝑅! + 𝑅!) = 𝐼!(𝑅! + 𝑅!)

If I2 from equation (1-1) is inserted, we got:

𝐼! 𝑅! + 𝑅! = 𝐼!𝑅!𝑅!

∗ (𝑅! + 𝑅!)

𝐼!𝑅! + 𝐼!𝑅! = 𝐼!𝑅! + 𝐼! 𝑅!𝑅!𝑅!

𝐼!𝑅!𝑅! = 𝐼!𝑅!𝑅!

𝑅!𝑅! = 𝑅!𝑅!. . . . . . . . . . . . . . . . . . . . . . ( 1 – 4)

Equation 1-4 is a form of Wheatstone bridge equality. If three of the resistances are known

and one of resistance is unknown, for example R4= Rx, hence:

𝑅! = 𝑅!𝑅!𝑅!

Principally, alternating current bridge is used to measure unknown inductance by

comparing it with standard known inductor. Figure 5 describes inductance comparator

bridge;R1andR2arethecomparator,andthestandardarmisLSinserieswithRS,whereas

LSishighqualityinductorandRSisvariableresistance.LxisunknowninductanceandRxis

theresistance.



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Figure 5 InductanceComparatorBridge

If the arm of the bridge is stated in complex form, therefore:

𝑍! = 𝑅! 𝑍! = 𝑅! + 𝐽𝑤𝐿!

𝑍! = 𝑅! 𝑍! = 𝑅! + 𝐽𝑤𝐿!

In equality:

𝑍! ∗ 𝑍! = 𝑍! ∗ 𝑍!

𝑅!(𝑅! + 𝐽𝑤𝐿!) = 𝑅!(𝑅! + 𝐽𝑤𝐿!)

𝑅!𝑅! + 𝑅!𝐽𝑤𝐿! = 𝑅!𝑅! + 𝑅!𝐽𝑤𝐿! …………… (1 – 5)

Two complex numbers are the same, if its real and imaginary are the same. By equating real

part of equation (1-5), hence:

𝑅!𝑅! = 𝑅!𝑅!

𝑅! = 𝑅!𝑅!

𝑅!

For the imaginary,

𝑅!𝐽𝑤𝐿! = 𝑅!𝐽𝑤𝐿!

𝐿! = 𝑅!𝑅!

𝐿!

Principle that is used for capacitance measurement is Capacitancy Comparator Bridge, which

is similar to Inductance Comparator Bridge. Figure 6 describes capacitancy comparator bridge. R1

and R2 as comparator arms, and the standard arm is Cs (high quality capacitor) which is series with

Rs (variable resistance). Cx is capacitance whose value is unknown and Rx is capacitor leaking

resistance.



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Figure 6. CapacitanceComparatorBridge.

If the arms of inductance comparator bridge are stated in complex form, therefore:

𝑍! = 𝑅! 𝑍! = 𝑅! − 𝐽/𝑤𝐶!

𝑍! = 𝑅! 𝑍! = 𝑅! + 𝐽/𝑤𝐶!

In equilibrium, hence:

𝑍! ∗ 𝑍! = 𝑍! ∗ 𝑍!

𝑅!(𝑅! −𝐽𝑤𝐶!

) = 𝑅!(𝑅! − 𝐽/𝑤𝐶!)

𝑅!𝑅! − 𝑅!𝐽𝑤𝐶!

= 𝑅!𝑅! − 𝑅!𝐽/𝑤𝐶! …………… (1 – 6)

The same with inductance comparator bridge, two complex number is the same if its real and

imaginary are the same. By equating the real part of above’s equation, we have:

𝑅!𝑅! = 𝑅!𝑅!

𝑅! = 𝑅!𝑅!

𝑅!

Hence, the imaginary is:

𝑅!𝐽/𝑤𝐶! = 𝑅!𝐽/𝑤𝐶!

𝐶! = 𝑅!𝑅!

𝐶!



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Equalibirum is obtained by controlling the value of variable load, and variation of load R2

and R1 to obtain minimum current flow in the galvanometer. After that the current that flows

thorugh Galvanometer is reduced by varying variable load Rs and keeping R2 and R4

constant. And then keep load Rs constant and change load R2 and R4, repeat the process

above until the bridge is in equalibirum. After reaching equalibirum, capacitance can be

obtained from the equation above.

If the bridge circuit is not ini equalibirum, then the current that flows to the

galvanometer causes a deviation of the galvanometer needle. The maginitude of the deviation

is a function of the galvanometer’s sensitivity. Hence, the sensitivity is calculated as current

per unit(ampere). The galvanometer needle deviation can be expressed linearly or the angle

per unit. The sensitivity S can be stated as

S = millimeters

µ𝐴 atau derajatµ𝐴 𝑎𝑡𝑎𝑢

radianµ𝐴

Thus the total deviation D is :

D = 𝑆 ×𝐼

The thevenin theorem is regularly used to find the current value that flows in the

Galvanometer hence the following equation is obtained :

I! = 𝑉!!

𝑅!! + 𝑅!

III. EXPERIMENT EQUIPMENT

1. LCR Meter

2. Variable Resistor

3. Variable Inductor

4. Variable Capacitor



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IV. EXPERIMENT PROCEDURE

1. Prepare all the equipment that will be utilized.

2. Prepare the components that will be measured.

3. Count manually the value of the components.

4. Then measure the components using RLC Meter.

5. Note the result of measurement.

6. Count total impedance of each load.

7. Find the power factor value from load impedance that is measured on LCR Meter and

power factor of load impedance that is stated on the load variable.

8. Compare power factor value of load that is measured by LCR Meter and load that is

stated on the load variable.



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MODULE 3

SINGLE PHASE POWER MEASUREMENT

I. OBJECTIVE

1. To know and understand the characteristic of power and power factor measurement

on alternating current circuit with different type of loads.

2. To know the working principle of single phase wattmeter, cos phi meter, amperemeter

and voltmeter.

3. To understand the variation of power type in alternating current system circuitry.

4. To know the usage of power of light bulb, and compare it with the value of power in

its packaging box.

II. BASIC THEORY

Power in electrical engineering, is defined as the amount of electrical energy that

is transferred in an electrical circuit in a time unit (energy per time). Different with direct

current direct current circuit, in alternating current circuit, there are 3 kinds of power;

True Power, Reactive Power and Apparent Power. The three has tight relation to one

another and it is represented by a triangle, and called as power triangle.

Figure 1. Power Triangle

The difference between these kinds of power in alternating current circuit is

caused by the characteristics of impedance inductive and capacitive component. In

alternating current circuit, inductive and capacitive component has a certain impedance



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value due to frequency. These inductive and capacitive components create lagging and

leading of current with respect to voltage, which will affect the multiplication between

voltage and current, and as a result, there are three kinds of power in AC circuitry.

The shape of power triangle is determined by the type of loads in the circuit;

whether it is resistive, inductive, capacitive or combined. The resultant of these loads is

called by impedance, and impedance has the combined characteristics based on which

components composing it. The characteristic of load means the type of power that is

absorbed, and the leading or lagging of the current with respect to voltage. The usage of

inductive /capacitive load will affect the current position with respect to the voltage,

which usually the difference is symbolized by phi, and the amount of cos phi is called as

power factor. Power factor is the ratio between active power and apparent power.

Hence, considering the angle shifting between current and voltage, power can be

stated as

S = V x I*= P + Jq

With:

S à in Volt-Ampere, apparent power

P à in Watt, active power

Q à in VAR, reactive power

V à in Volt, voltage

I* à in Ampere, current

Notice in I, there is a star symbol (*). This symbol states that the value of current

utilized is conjugated mathematically. This equation also states that angle that is formed

by voltage and current is the subtraction between angle that is formed by voltage and

angle that is formed by current. Here is the illustration:



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Figure 2. Relationship between voltage and current angles.

With :

α = θ1 – θ2

S = V x I* = V⦟ θ1 x I ⦟- θ2

S =V x I ⦟θ1 – θ2

In this experiment, analog measurement device will be utilized to measure current,

voltage, power and power factor. Analog measurement device mainly has similarities in

having firm and rotating coil that has been calibrated so the movement of its hand

matches with the amount that being read. There are some construction types of analog

measurement device, for example:

a. Moving Coil Type

How moving coil works is that it used 2 permanent magnets that will induct

coil that has current and connected with the hand of the measurement device. The

bigger the induction, the coil will rotate until the hand hits the damper. Moving Coil

utilizes Lorentz Force principle.

Figure 3. Moving Coil Construction



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b. Moving Iron Type

It uses two soft steels; one is mounted in the coil and the other is connected

to the hand of the measurement device. When current flows to the coil,

electromagnetic field will happen and those two steels will have permanent field.

• Attraction type: pair of steels will have different poles when facing one another.

• Repulsion type : pair of steels will have the same poles when facing one another.

Figure 4. Repulsion type Figure 5. Attraction type

c. Electrodynamic type

How it works is almost the same as moving coil, but the permanent magnet

in moving coil, here is replaced by a coil that has current flowing through it.

Figure 6. Electrodynamic type construction

d. Induction Type

i1

i2

Pointer Movable Coil

Scale

Fixed Coil



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If inducting coil has current flowing through it, an alternating magnetic field

will happen. This magnetic field will create rotating current in the metal disk, and

the current will generate magnetic field too hence interaction with magnetic field

from inducting coil creates rotating force in metal disk.

Figure 7. Induction type construction

e. Electrostatic Type

There are two plates, both in half circle shape, that is set to be next to each

other, but one of them is not moving. These two plate is connected to an axis. The

plate that can move has a hand to show the measurement result. These two plate will

have current flowing through it and create electrostatic field that works based on

coulomb law. The moving plate will move due to the two force on the two plates

that have different potential.

Figure 8..Electrostatic Type construction

f. Thermocouple Type



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Two conductors that differs will be united in one end and separated in the

other end. The united end will convert heat energy that is received and will be flown

to the other end. Due to the different of conductor type, there is a potential different

in the tip of the conductor. Usually this type is combined with moving coil type by

replacing its source from heat energy.

Figure 9. Thermocouple type construction

This is the measuring process by analog measurement device

Figure 10. Measuring process by analog measurement device

Meanwhile for digital measurement device, it is divided into 2 categories:

a. Digital Readout Instrument.

Digital readout instrument is basically an analog device, where the

measurement process still uses analog circuit, but the reading of the measurement is

done digitally, like this:

Figure 11. Measurement process by digital readout instrument



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b. Digital Instrument

This instrument fully uses ADC and microprocessor in data sampling until

the reading process of the measurement.

Figure 12. The measurement process of digital instrument

III. EXPERIMENT EQUIPMENTS

1. AC Amperemeter

2. AC Voltmeter

3. Single phase Wattmeter

4. Cos phi meter

5. Resistive load

6. Inductive load

7. Capacitive load

8. Light bulb

9. Fluorescent lamp

10. Cables

IV. EXPERIMENT CIRCUIT

Figure 13. The experiment circuit

*for wattmeter and cosphimeter wiring can be seen underneath the instrument itself.



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V. EXPERIMENT PROCEDURES

A. Measuring power and power factor from different types of loads

1. Setting the experiment circuit as written in figure 13

2. Setting up the wattmeter and cos phi meter based on the guideline in the

instrument.

3. Setting up the load combinations

4. Turning on the source

5. Measuring and reading the measurement of voltmeter, amperemeter, cos phi

meter, and wattmeter

6. Repeating steps 3 to 6 with different types of loads.

B. Measuring power of light bulb and fluorescent lamp

1. Setting the experiment circuit as written in figure 13

2. Setting up the wattmeter and cos phi meter based on the guideline in the

instrument.

3. Replacing the load by light bulb

4. Turning on the source

5. Measuring and reading the measurement of voltmeter, amperemeter, cos phi

meter, and wattmeter

6. Comparing the result with the power that is stated in the lamp’s packaging box.

7. Repeating steps 3 to 6 with fluorescent lamp.



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MODULE 4

POWER QUALITY AND THREE PHASE POWER MEASUREMENT

I. OBJECTIVES

1. Understanding the definition of power quality

2. Understanding types of disturbance in power quality

3. Understanding the three phase power measurement using 1 three phases wattmeter

and 2 single phase wattmeters.

4. Understanding the power factor measurement of RLC load of three phase circuit.

5. Understanding how wattmeter works.

II. BASIC THEORY

Power quality is a condition between electricity source and the supplied electrical

appliances. The power quality describes how good or bad the quality of electricity due to

some disturbances that may happen in electricity system.

Usually what are talked about in power quality is the disturbances that happen.

Generally, the quality of power has three important parameters, which is voltage, current

and frequency. Every deviation from voltage, current and frequency from its normal

condition that can make the quality of power delivered and system performance worse,

and it could create failure of system or the wrong electrical load operation from

consumer side.

Here are the problems of power quality:

a) Voltage Drop, voltage that disspates due to impedance of the circuit

b) Transient, a phenomenon that involves variable change(voltage, current, etc) that

occurs during transition period from steady state to another state, transient is divided

into :

a. Impulse transient : transient that only has one direction of polarity

b. Oscillatory transient : transient that has two directions of polarity



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c) Gejala Perubahan Tegangan Durasi Pendek (Short-Duration Variation) Short

Duration Variations is a voltage value changing phenomenon in short priod of time

which is less than a minute

• Based on the duration of the incident, SDV consist of 3 types, which are :

1. Instantaneous : Voltage change occurs for 0.5 until 30 cycles

2. Momentary : Voltage change occurs for 30 cycles until 3 seconds

3. Temporary : Voltage change occurs for 3 seconds until 1 minute

• Based on the voltage change value, SDV consist of 3 types, which are

1. Interruption : reduction of voltage or electrical current until it is below 0.1

pu for a period of time not exceeding 1 minute

2. Sag : reduction of voltage or electrical current 0.1-0.9 pu in a period of 0.5

cycles - 1 minute

3. Swell : increase of voltage or electrical current on 1.1-1.8 pu in 0.5 -1

minute

d) Long Duration variations is voltage changing phenomenon, in a long time period

which exceed 1 minute, it is divided into 3 types which are sustained interruption,

undervoltages, and overvoltages.

e) Voltage unbalance, a pehomenon where there is a voltage value difference in a three

phase system and also its phase angle

f) Wave distortion, for example is Harmonics which is a deviation phenomenon of a

wave (voltage and current) from its ideal form which is a sinusoidal wave.

g) Flicker : voltage variation caused by fast and continuous load change.

h) Frequency deviation, types :

a. Frequency variation

b. Radio Frequency Interference : disturbance caused by electromagnetic induction

from an external source

c. EMF

The measurement of three phase power measurement use couple of methods:

• Measurement using 1 three phase wattmeter (poly phase)

• Measurement using 2 single phase wattmeter (single phase)



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• Measurement using 3 voltmeters and 3 amperemeters

• Measurement using 3 single phase wattmeter (single phase)

• Measurement using 3 V-A meter.

In this experiment, methods being used are 2 single phase wattmeters and 1 three

phase wattmeters.

There are three construction types of wattmeter:

1. Electrodynamic Type

2. Induction Type

3. Thermocouple Typ

One of the most common AC wattmeters is electrodynamometer type wattmeter.

Figure 1. Electrodynamometer single phase wattmeter diagram.



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1. 1 polyphase wattmeter

2. 2 single phase wattmeters

3. Cos phi meter

4. Resistive load

5. Inductive load

6. Capasitive load

7. Cables


Here is the circuit of wattmeter installation in three phase circuit:

a) Using 1 poly phase wattmeter.

Figure 2. Circuit of 1 polyphase wattmeter



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b) Using 2 single-phase wattmeter

Figure 3. Circuit of 2 single phase wattmeters.

V. EXPERIMENT PROCEDURE

A. Power measurement with 1 poly phase wattmeter.

1. Setting up experiment with Z1 using resistive load, Z2 using inductive load, Z3

using capacitive load, using wye or delta configuration of three phase load.

2. Connecting first probe to R phase, and connecting output from probe which are

P1 and A1 to first load using three phase circuit.

3. Connecting P2 to S phase, and the second load that is not connected to first load.

4. Connecting T phase to second probe, then connecting the output of this probe

which are P3 and A2 to third load that is not connected to second load.

5. Connecting first probe to cos phi meter ke R phase, then connecting output from

probe P1 and A1 to first load in three phase circuit.

6. Connecting P2 to cos phi meter and S phase to the second load that is not

connected to first load.



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7. Connecting T phase to P3 and third load to three phase circuit that is not

connected to second load.

8. Checking if cable connection installed properly and load had been switched on

before circuit is on.

9. After being turned on, observe and note the value that is read by two wattmeters

and cosphi meter.

B. Power measurement using 2 Single Phase Wattmeter.

1. Construct the circuit with Z1 as resistive load, Z2 as inductive load, and Z3 as

capacitive load, and create wye or delta configuration on three phase loads.

2. Connecting phase source R to the first single phase wattmeter, and from

wattmeter connect it to Z1 load of three phase load configuration.

3. Connecting phase source S directly to Z2 load of three phase load configuration.

4. Connecting phase source T to second single phase wattmeter, and from

wattmeter connects to cosphi meter. Then, connect Z3 load to three phase load.

5. Checking if cable has installed properly and load had been switched on before

the circuit is on.

6. After being turned on, observe and note the value on wattmeters and also cos

phi meter



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MODULE 5

LIGHTING MEASUREMENT

I. OBJECTIVE

1. Understanding lighting concept

2. Understanding units in lighting measurement

3. Understanding lighting measurement device

4. Knowing application and usage of lighting measurement.

II. BASIC THEORY

Light is an electromagnetic radiation that can be caught by eyes and has

wavelength from 0.4 x 10-4 -~ 0.75 x 10-4 cm. Light also can be defined as the amount of

lighting on a working plane that is needed to do activity effectively. Based on the sources,

lighting is divided into 2 kinds :

a. Natural lighting

Natural lighting is lighting that is based on sun rays.

b. Artificial lighting

Artificial lighting is lighting that is based on any other sources, except sun rays.

Beside its source, a lighting system can be divided into 3 kinds, based on the

distribution :

a. Distributed lighting system

In this system, light illumination is spread evenly with the same strong light intensity

on the entire horizontal surface in the room.

b. Localized lighting system

In this system, light is provided to provide highly selective illumination in a

relatively wide place or field. Usually installed with common lighting, where

localized lighting is used as lighting for work and distributed lighting is used as

basic lighting.



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c. Directed lighting system

In this system, light is concentrated from a particular direction to the work plane

within the space/limited area or directed to specific object such as painting.

One of the most common artificial lighting sources that utilized by human is lamp.

Lamps can be categorized into several types, according to the method that is used to emit

light. These lamps also has differences in shapes, power consumption, and also the

heat/brightness. :

a. Light Bulb

Light in light bulb is resulted from tungsten made-filament that shines due

to heat. Only 8-10% of the energy is converted to light; the rest is converted to heat

form. Halogen lamp is included to this group.

Basically, filament in light bulb is a resistor. If an electrical current goes

through it, the filament turns extremely hot, and its temperature will be

approximately 2800 K until 3700 K in its peak. This causes the light color from light

bulb is in yellow redish. In that extremely high temperature, filament will produce

light in a visible wavelength.

b. Fluorescent lamp

The light in this lamp comes from phosphoric powder which covers the

inner part of lamp’s tube. The powder determines the color of the light produced.

More than 25% of energy consumed by this lamp is converted into light.

When a 220 volt of AC voltage is connected to one set of fluorescent lamp,

the voltage of the tip of starter is enough to cause neon gas in starter tube to be

ionized and it will cause the starter from normally open to closed, hence the neon

gas inside will be deionized. In this closed starter condition, a current will flow to

heat filament of fluorescent lamp tube and the gas inside the tube will be ionized.

Once the neon gas in the starter tube is cooled enough, the bimetal in starter tube

will be opened again so the ballast will produce a high voltage spike and causes

electron jump from the two electrodes and shines the fluorescent layer on the lamp’s

tube.

c. HID (High Intensity Discharge) lamp



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The light in this lamp is caused by electrical prod using metal vapor.

Mercury lamps and metal halide lamps are some examples of HID lamp.

d. LED (Light-Emmiting Diode) lamp

This lamp is composed by a set of LED to emit light. The LED light will

appear without heating of the components. LED needs DC source to energize it with

low voltages. Due to that reason, a step down transformer circuit is also equipped to

decrease source’s voltage that goes in to the circuit.

In lighting measurement, some specific terms are used, for example:

1. Light intensity

It is the strength of light from a light source. The amount is measured in

candela (cd) unit.

2. Lumen

Lumen (SI unit, symbolized by lm) is a unit for light flux that is emitted in

a solid angle unit by a source with light intensity of 1 candela. One lumen is equal to

the amount of light uniformly emitted of 1 candela in 1 steradian solid angle. It is

written 1 lm= 1 cd sr.

3. Illumination

Illumination or lighting intensity is the amount of light exposing a surface.

Illumination has unit of footcandles (fc) or in lux form; 1 lux= 1 lumen /m2

4. Steradian

Steradian (Ω) is a unit of space angle for a ball area in radius distance

Figure 1. Relationship of steradian, ball area, and radius distance.



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Here is the conversion of units above:

Measurement tool utilized is luxmeter. Luxmeter has lux unit, which is defined as

a metric unit of light on a surface. Luxmeter has light intensity range from 1 to 100,000

lux. Luxmeter is constructed by three main components; case, LED and photodiode. The

working principle of luxmeter is to convert light energy to electrical current and it will be

shown on LED screen.

Illumination measurement basically is a measurement that uses the approach of

point source. Illumination measurement is done in a dark place where there is no

reflected light received by the luxmeter sensor. There are three illumination

measurements:

1. General measurement

It is a measurement that is done in one whole room. This measurement is done

by dividing the room into several measurement points with the same distance from

one point to another.

2. Local measurement

It is done on a specific object. The object will be divided into several

measurement points.

3. Reflectant measurement

From To With data Equation Candela (Iv) Lumen (Φv) angle α Φv=2πIv (1−cosα2)

Lumen (Φv) Candela (Iv) angle α Iv=Φv2π (1−cos½α)

Lumen (Φv) Lux (Ev) Area A (m2) Ev=ΦvA

Lux (Ev) Lumen (Φv) Area A (m2) Φv=Ev⋅A

Candela (Iv) Lux (Ev) Measurement distance D (m)

Ev=IvD2

Lux (Ev) Candela (Iv) Measurement distance D (m)

Iv=Ev⋅D2



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It is a measurement of reflectant by doing twice of measurement. First

measurement is to measure lighting intensity on the surface by putting photo cell

facing the light source. The second measurement is by turning over the photocell

facing the surface, and pulling photo cell until the number on display shows highest

number. The amount of reflectant is formulated here:

Reflectant= (Measurement 2/ Measurement 1) x 100%

Lumen measurement is important to save energy in lighting. The application of

lumen measurement can be utilized on these fields:

1. Lighting level measurement on buildings

2. Luminaire light intensity distribution measurement

3. In videography, photography and architecture.


1. Luxmeter LX-1108

2. 1 Light bulb

3. 4 Fluorescent Lamp

4. 1 LED Lamp

5. AC Power Supply

IV. EXPERIMENT PROCEDURE

A. Voltage variation general measurement

1. Install the lamp in fitting in the middle of the room

2. Turn on the power supply

3. Adjust the power supply in the voltage that desired

4. Make sure the light in the room only comes from that source only.

5. Adjust the luxmeter position under the light with distance 1 meter above the

floor.

6. Make sure the light that is caught by luxmeter sensor is not interfered by

shadow.



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7. Turn on the luxmeter, open the sensor cover, and note the value on the luxmeter.

8. Repeat steps 3,4,5,6,7 with different voltage variations.

B. Lamp brand variation general measurement.

1. Install the lamp in the fitting in the middle of the room.

2. Turn on power supply and adjust power supply at 220 V

3. Make sure the light in the room only come from the lamp.

4. The measurement will take place at 12 points that have been decided.

5. Adjust the position of luxmeter at the first point with 1 meter distance above

ground.

6. Make sure the light that caught by luxmeter sensor is not covered by shadow

7. Turn on the luxmeter, open the sensor cover and note the value on the luxmeter.

8. Repeat steps 5,6, and 7 until the 12th point.

9. Repeat steps 1-8 to each different lamp brands.

C. General measurement of lamp type variation

1. Install the lamp in the fitting in the middle of the room.

2. Turn on power supply and adjust power supply at 220 V

3. Make sure the light in the room only come from the lamp.

4. The measurement will take place at 12 points that have been decided.

5. Adjust the position of luxmeter at the first point with 1 meter distance above

ground.

6. Make sure the light that caught by luxmeter sensor is not covered by shadow

7. Turn on the luxmeter, open the sensor cover and note the value on the

luxmeter.

8. Repeat steps 5,6, and 7 until the 12th point.

9. Repeat steps 1-8 to each different lamp type



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MODULE 6

GROUNDING RESISTANCE MEASUREMENT

I. OBJECTIVE

1. Knowing the amount of grounding resistance of a place.

2. Knowing and understanding the function and usage of grounding resistance

measurement and its application daily.

3. Knowing the earth ground tester working principle

II. BASIC THEORY

Grounding resistance is a resistance of a grounding system that aims to divert

lightning current to the ground so there will be no loss happened due to grounding current.

The aim of grounding:

a. Safety and security

b. The tunnel for leakage current

c. Protection of device.

In an electrical installation, there are four parts that need to be grounded, they are:

a. Every installation part that is made from conductor (metal) and can be easily

touched by human.

This is necessary so that the potential of those metals will always be the same with

ground potential, where human stands, so it is not going to be dangerous for human

to touch it.

b. The lower part of lightning arrester.

This is necessary so lighting arrester can function well, which is to divert the

electricity from lightning to the ground directly.

c. The lightning rod on the upper part of transmission line.



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This rod acts as lightning arrester. Since it is located along the transmission line, all

of the legs of transmission poles has to be grounded so the lightning can be diverted

to the ground via the poles’ legs.

d. Neutral point of transformer or generator.

This relates with the protection necessity.

Lightning happens due to potential difference between cloud and earth or between

cloud and another cloud. If the potential difference between cloud and ground is huge,

there will be an electron disposal from cloud to ground or vice versa, to reach equilibrium.

The mechanism of lightning is started by downward leader. This movement will reach the

ground, so the negative charge brought by downward leader will increase positive charge

induction on ground surface. Then the positive charge in a huge amount will move

upward by upward leader, responding downward leader movement, and a contact from

the two happens, as a lightning.

Grounding system is related to lightning protection. Lightnng protection is dvided

into:

a. Internal protection system

Its objective is to protect objects from indirect lightning flash which is

magnetic field induction. Here are the types of internal protection system:

1. Bonding

2. Surge Protection Devices

3. Shielding

4. Safe Distance

b. External protection system

External protection system is used to protect object from direct lightning flash.

The types are:

1. Dissipation Array System (DAS)

Dissipation Array System enables lightning flash not to happen in a

location. Point discharge that has sharp point is placed in several places of



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buildings’ roof, to move electric charge of that object to air. The charge released

by point discharge will decrease the potential difference between ground and

cloud, and reducing the cloud’s ability to release charge to earth.

2. Charge Transfer System (CTS)

Charge Transfer System is the most common external lightning protection.

In this system, lightning will strike but the position of the strike had been

predicted, so it will not strike the other parts. The methods of CTS are:

a. Franklin Rod

b. Faraday Cage

c. Radioactive (Early Streamer Emission Air Terminal)

In grounding system, several important parts are:

a. Air terminal

b. Down conductor

c. Grounding electrodes

d. The soil

The wellness of grounding system is determined

by the amount of grounding resistance amount, where the

value will influence the grounding resistance. The

standard for good grounding is the grounding amount is

not more than 5 Ohm.

Factors that influenced grounding resistance value:

a. Soil condition

b. Humidity

c. Type of soil

d. The depth of electrode

e. Type of grounding electrode

f. Area of down conductor

g. Temperature

Figure 1.Grounding system



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h. Air terminal type

To reduce the grounding resistance value:

a. Paralelling grounding electrodes

b. Changing the grounding electrode type

c. Creating pool to make the soil humid

d. Adding salt to the ground

e. Increasing the depth of grounding electrodes

There are two methods to measure grounding resistance of a location

a. Four electrode method

The grounding resistance measurement with this method need these equipments:

• 4 steel rod

• 1 Amperemeter

• 1 AC power supply voltmeter

Configuration:

4 steel rod (C1, P1,P2,C2) are mounted to the ground on the same line with

distance to one another of a meter. Between P1 and P2, voltmeter is placed and

between C1 and C2, amperemeter and 110 AC/220 VAC power supply are

connected, like below:

Figure 2. Four points method



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Measurement method:

Connecting power supply, measuring how many amperes of current flowing

between C1 and C2, say I Ampere. Then measuring how many potential difference

between P1 and P2, say V (volt). Insert all of them in:

Rho = 2 π a R

where π = 3,14

a = distance between steel rod

R = V/I

b. Three-point method

Three point method is the other method to measure grounding resistance.

Let’s say there are 3 grounding rods; rod 1 is the one which want to be measured,

and the rest are the helpers for the measurement. The configuration is below:

Figure 3. Three point method

Earth Ground Tester is a device to measure resistance value of a grounding.


1. Earth Tester Metroohm

2. Connecting cables

3. Grounding nails

4. Hammer



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Figure 4. Earth Tester Figure 5. Ports of Earth Tester


Figure 6. Experiment circuit


1. Preparing all the equipment needed

2. Clipping 2 connecting cables to down conductor

3. Placing the end of the two cables to Earth Tester at port C1 and P1

4. Mounting the nails to the ground with the straight line of distance of 5 or 10 meter

(first experiment uses 5m, second uses 10m) from down conductor, about ¾ of nails

height deep.



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5. Clipping the connector cable to the nails and putting the end of the cable to P1 at

earth tester.

6. Mounting the grounding nail to the ground with 5 meter distance from P1 nail (has

to be on a straight line), ¾ of the nails deep.

7. Clipping the connector cable to the grounding nails and putting the end of the cable

to C1 earth tester.

8. Make sure the cables are properly connected.

9. Turning on the earth tester, put the range of earth tester at 20 ohm.

10. Press test button, and note the value shown on earth tester as the grounding

resistance of that area.



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MODULE 7

ENERGY CONSUMPTION MEASUREMENT

I. OBJECTIVE

1. Understanding how kWh meter works.

2. Knowing the difference of analog kWh meter and digital kWh meter.

3. Knowing the advantages and drawbacks of each type of kWh meter.

II. BASIC THEORY

Energy is the amount of power consumed in a certain time. kWh meter is the

tool used to measure the power consumption on a consumer. kWh meter is basically

divided as analog type and digital type:

On analog kWh meter:

Figure 1. Analog kWh meter structure

On this analog kWh meter, basically there are 4 parts; driving system, moving

system, braking system and registering system.

1. Driving System



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This part is consisted of 2 electromagnets called as shunt magnet and series

magnet. The voltage coil that is connected with supply is put in the center of shunt

magnet. The current coil is in series with load. The coil will carry load’s current and

producing proportional flux with load’s current.

2. Moving System

The moving system in analog kWh meter consists of aluminum plate that is

perpendicular with the rotating axis. The shaft of this plate is connected with the

hand in the front part of kWh meter to show the information of energy consumption.

The aluminum plate is driven by torque coming from magnetic field that is inducted

from eddy current in aluminum plate.

3. Braking System

The braking system in analog kWh meter is controlled by a permanent

magnet that is located across the driving system’s magnet. This permanent magnet

will create magnetic field that opposes the direction of magnetic field that drives

aluminum plate and as a result, braking torque happens.

4. Registering System

The registering system consist of a gear that directly interact with aluminum

plate and hand on kWh meter to show the nmber, hence the amount of plate rotation

will be read.

In digital kWh meter, the working principle uses microprocessor to get the value

of energy consumption. In this type, the measurement is more accurate. But this kWh

meter has more complex component such as IC, display, voltage sensors, etc. The

components of digital kWh meter is:

• Board / IC

• Display

• Voltage and current sensor

• Voltage and current transformer

• Port I / O



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Here is the flowchart of process in digital kWh meter:

Figure 2. The flowchart of process in digital kWh meter


1. Analog KWh meter

2. Cables

3. Digital wattmeter

4. Lamp Fitting

5. 10 100 W lamps


Figure 3. Experiment Circuitr


1. Setting up the circuit as had been shown on the module.

2. Noting the initial value of kWh meter

3. Activating AC source

4. Waiting for 1 hour



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5. Noting the result of kWh meter’s measurement

6. Comparing data from kWh meter, length of experiment, load power and the reading

of wattmeter.



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MODULE 8

POST TEST

Post test is a final test on all the materials during the Electrical Measurement

laboratory activity. All students taking this course must take the post test and it will be

included in the final scoring. The time and the place of post test will be informed later on.

Documents

LABORATORY MODULES ELECTRICAL MEASUREMENT · Measurement Lab. 10 IV. EXPERIMENT PROCEDURE 1. ... Then measure the components using RLC Meter. 5. ... Q à in VAR, reactive power V