LABORATORY MODULE ELECTRIC CIRCUIT

LABORATORY MODULE ELECTRIC CIRCUIT HIGH VOLTAGE AND ELECTRICAL MEASUREMENT LAB ELECTRICAL ENGINEERING DEPARTMENT FACULTY OF ENGINEERING UNIVERSITAS INDONESIA DEPOK 2018

MODULE 1 LABORATORY BRIEFING All practicants are required to attend the briefing for the reason that it is included in the scoring system. Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 1

I. OBJECTIVE MODULE 2 ELECTRICAL BASICS AND MESH ANALYSIS 1. To know definition of electricity, current, and voltage 2. To use mesh analysis in an electrical circuit 3. To understand use of super mesh 4. To simplify solving voltage and current equation of an electrical circuit II. BASIC THEORY 1. Electrical Basics Electricity is a form of energy that is caused by displacement of electrical charge. In discussing about electrical basics, there is a close link with voltage, current, and resistance. Voltage (V) is defined as the change of work that is needed to move a charge of 1 C, which can be formulated to an equation = ( ) Current (I) is defined as the amount of charge that flows per unit time, which can be formulated to an equation I = (A ) Current requires the presence of voltage source, load, and a conducting wire to flow (closed loop). Resistance is the parameter of each element in limiting the flow of electricity. Electrical resistance can also be defined as collision between free electrons (that flows in the Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 2

conductor) with fixed charges that are in the material s atomic bond. The magnitude of resistance depends on density, length, and material s cross-sectional area. Resistance can be formulated into an equation = ρ A (O ) 2. Electrical Element Electrical element can be divided into two types based on their activeness, which are active element and passive element. Active element has characteristics which are it can supply power, control current/voltage on a circuit, as well as having gain function. Examples are batteries, diodes, and transistors. Passive element has characteristics which are it can only absorb power, cannot control current/voltage, as well as not having gain function. Examples are resistor, inductor, and capacitor. Power sources can be divided into two types, which are independent sources and dependent sources. a. Independent Sources: a source whose magnitude and characteristics are not affected by other elements. b. Dependent Sources: a source whose magnitude and characteristics are affected by other elements. Dependent sources are divided into four types, which are: 1. Voltage-Controlled Voltage Source (VCVS) 2. Voltage-Controlled Current Source (VCCS) 3. Current-Controlled Current Source (CCCS) 4. Current-Controlled Voltage Source (CCVS) 3. Fundamental Laws Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 3

a. Ohm s Law The amount of electrical current (I) that flows through a wire or conductor will be proportional to the potential difference/voltage (V) that is applied to it and inversely proportional with its resistance (R) Or it can be said that the voltage in a resistor is proportional to the current in that resistor. Ohm s law can be formulated into an equation V = I. R With V as the voltage, I as the current flowing and R as the resistance in a circuit. b. Kirchoff s First Law (Kirchoff s Current Law, KCL) Amount of current that goes into a node is equal to the amount of current that goes out of that node Kirchoff s First Law is formulated into an equation ΣI = ΣI c. Kirchoff s Second Law (Kirchoff s Voltage Law, KVL) In a closed circuit, the algebraic sum of electromotive force (E) and the sum of potential drop is equal to zero Kirchoff s Second Law is formulated into an equation Σ = 0 4. Mesh Analysis On mesh analysis, some things need to be considered : Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 4

1. Circuit has to be on the same plane 2. Active element used is a voltage source 3. Passive element used is an impedance 4. Uses Ohm s law and Kirchoff II 5. Determine the current for each closed circuit 6. Create voltage equation How to acquire Mesh equation : 1. Decide value of each element and source 2. Create clockwise Mesh current on each Mesh 3. If the circuit only contains voltage source, use Kirchoff voltage law around each Mesh 4. If the circuit only contains current source, temporarily change circuit given by substituting each source of its type with an open circuit. By using the Mesh currents, use Kirchoff s Second Law around each Mesh or super Mesh in this circuit. III. EXPERIMENT TOOLS 1. DC voltage Source = 1 piece 2. DC voltmeter = 3 pieces 3. DC ampere meter = 2 pieces 4. Load = 5 pieces 5. Cables IV. EXPERIMENT CIRCUIT Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 5

V. EXPERIMENT PROCEDURE Picture 1. 1. Arrange experiment circuit based on picture 1! 2. Write down voltage V1, V2, V3 and current A1,A2 for changing voltage source that matches with the experiment table VI. QUESTIONS AND ASSIGNMENTS 1. Calculate the value of I1 and I2 with Mesh analysis for each changing voltage source (V1) 2. Find the measurement error for each changed value of voltage source (V1) and calculate the average error 3. Draw chart V1 against V2, V3, A1, A2 and write down the equation that states their connection Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 6

MODULE III LINEARITY AND NODAL ANALYSIS I. OBJECTIVE 1. Investigate a linear circuit 2. Use Nodal analysis in an electrical circuit 3. Understand the use of super node 4. Simplify solving current and voltage equations of an electrical circuit II. BASIC THEORY 1. Linearity A function or mathematical equation can be considered linear when two quantities are proportional to one another. There are two ways to prove a linear equation/function, which are additivity and homogeneity. Additivity : f(x + y) = f(x) + f(y). Homogeneity : f(αx) = αf(x) for every α. Linear circuit can be formed from independent sources, dependent sources and linear elements. The magnitude of voltage given to a linear circuit will be proportional to the magnitude of current that flows in the circuit. Examples of linear elements are resistors, inductors, and capacitors. Whereas examples of non-linear are BJT, Diode, and Transistors. 2. Nodal Analysis On Nodal analysis, a few things need to be considered : 1. Active element used is current source 2. Passive element used is admittance 3. Uses Ohm s law and Kirchoff I Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 7

4. Determine node voltage 5. Create current equation How to acquire nodal equation : 1. Show values for all elements and sources. Every current source has reference value. 2. Choose one of the nodes as reference. Write down node voltage on every node that was measured against the reference. 3. If only current source is present, use Kirchoff First Law on every non reference node. 4. If the circuit contains voltage source, temporarily change the given circuit by substituting every source of that type with a short circuit. By using node voltage to determined reference. Use Kirchoff I on every node or current super node in the changed circuit III. EXPERIMENT TOOLS a. DC voltage Source = 1 piece b. c. d. DC voltmeter DC ampere meter Load = 3 pieces = 3 pieces = 5 pieces e. Cables IV. EXPERIMENT CIRCUIT L boratorium, Tegangan Tinggi dan Pengukuran Listrik 8

V. EXPERIMENT PROCEDURE Gambar 1 1. Arrange experiment circuit based on picture 1! 2. The controlled value is the current that flows out of the DC power supply, so that value V0 is controlled by changing voltage on DC power supply 3. Record voltage V1, V2, V3 and current A1, A2 for changing current source (A0) that matches with experiment table VI. QUESTIONS AND ASSIGNMENTS Linearity 1. Create chart V (t) vs I (t) based on experiment on millimeter blok! Nodal Analysis 1. Calculate value of V1, V2, and V3 with nodal analysis for every current source change. 2. Find measurement error for every changed value of current source and calculate its average error. 3. Draw chart of current source magnitude against V1, V2, V3, A1, and A2 and write down the equation that states their connection. EXPERIMENT IV SUPERPOSITION ANALYSIS AND THEVENIN I. OBJECTIVE 1.Determine voltage on a linear circuit when there are more than one voltage source 2.Understand the use of Thevenin theorem 3.Prove Thevenin theorem on an electrical circuit Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 9

4.Simplify solving voltage and current equation of a circuit II. BASIC THEORY In terms of electrical, electrical components can be categorized to be linear and nonlinear. Examples of linear components are resistor, inductor, and capacitor, while examples of non-linear components are transistor and diode. In a linear circuit, there are a few theorems that can be used to simplify analysis and circuit calculation: 1. Superposition In every linear networks that contains a few sources, voltage or current that flows through every load or source can be calculated by performing algebraic sum of every voltage or current that is produced by each independent source that operates alone, with every independent voltage source changed with short circuit and every other current source changed by open circuit. 2. Thevenin Theorem i(t) NA NB Picture 1 NA : Circuit that contains passive and active elements Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 10

NB : Circuit that contains onlh passive elements From NA to NB flows current i(t) 1. Place voltage source V(t) that has a value which such a way that current doesn t flow from NA to NB + - 1 V(t) NA 1' NB Picture 2. 2. i(t) = 0 means NA and Nb can be terminated on terminal 1 1 3. Voltage equation on 1 1 in an open circuit state: 4. -V1-1 + V(t) = 0; V(t) = V1-1 5. V1-1 is the circuit voltage in open circuit state(v open circuit) 6. Calculate V(t) = V1-1 7. Reverse polarity V(t) and erase voltage/current source on NA 8. So that from NA to NB flows current i(t) that is same as before III. EXPERIMENT TOOLS a. DC voltage source = 1 piece b. DC voltmeter = 1 piece c. Dc ampere meter = 1 piece d. Load = 4 pieces e. Cables IV. EXPERIMENT CIRCUIT Thevenin Theorem Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 11

Gambar 1 V. EXPERIMENT PROCEDURE 1. Create circuit based on picture 1 2. Turn on power supply and do warm up for a few moments and adjust position of voltage source 3. Insert S1&S3 to position 1 and then insert S4. Record Va and load current IL close loop. Repeat for different voltages 4. Return magnitude of power supply to position 0 5. Open S4 and then place voltmeter with pole (+) on the tip of the Thevenin circuit and pole (-) on reference (Voc in the picture). Record Voc with Vs same as step 3 6. Return magnitude of power supply to position 0 7. Move S1&S3 to position 2 and insert S2, after that move position of voltmeter with pole (+) to the tip of the load and pole (-) to the tip of the Thevenin circuit(vth in picture). Record load current IL with voltage that is the same as with Voc on step 5 VI. QUESTIONS AND ASSIGNMENTS 1. Does load current IL on V.1.3 and V.1.7 have the same magnitude? Explain! 2. By not changing the experiment circuit, can IL on V.1.7 be made to 2 x IL on V.1.3? explain! Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 12

3. Compare measurement results of Voc against the actual calculation result! Calculate % error! MODULE V NORTON ANALYSIS I. OBJECTIVE 1. Understand the use of Norton Theorem 2. Prove the Norton Theorem on an electrical circuit 3. Simplify solving voltage and current equation from an electrical circuit II. BASIC THEORY Norton Theorem 1. Place current source based on picture 3 that has a value so that i(t) is the same as ig, and no current flow to NB Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 13

1 NA i(t) ig NB 1' Picture 1 2. This means i(t) = ig. Short circuit at terminal 1-1. NA and NB released at 1-1. 1 NA i(t) NB 3. Calculate short circuit current ig Picture 2 1' 4. Reverse polarity of ig and erase all active elements on NA 5. Thus from NA to NB flows current i(t) that is the same as before. 1 i(t) NA ig NB 1' Picture 3 III. EXPERIMENT TOOLS a. DC voltage source = 1 piece b. DC voltmeter = 1 piece c. DC ampere meter = 1 piece d. Load = 4 pieces e. Cables Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 14

IV. EXPERIMENT CIRCUIT Picture 1 V. EXPERIMENT PROCEDURE 1. Arrange circuit based on picture 4 2. Turn on power source and adjust position at voltage source 3. Insert S1 to position1. Record Vs and load current IL (A2) close loop. Repeat for different voltages. 4. Insert S3. Record short circuit current Isc (a1) with Vs from step 3 5. Return power source to position 0. Close S1, open S3 and move S1 to position 2. Adjust power source at the position of the current source. Exchange polarity of ampere meter A1 and record load current IL (A2) for the same current (A1) based on step 4. VI. QUESTIONS AND ASSIGNMENTS 1. Does load current IL on V.2.3 and V.2.5 have the same magnitude? Explain! 2. Is load current IL on Norton and Thevenin experiment the same for the same vs value? Why? 3. Compare measurement result Isc with calculation result! Calculate the 5 errors! 4. Find RTH from experiment result and compare with RTH from actual calculation result! Calculate % error! 5. Create chart Voc vs Isc with the same Vs! Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 15

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MODULE VI TWO PORT CIRCUIT I. OBJECTIVE 1. Determine the admittacne and impedance parameter of a two port circuit 2. Determune the circuit parameter to simplify and systemize network analysis with two linear layover points II. BASIC THEORY Two port cicuitcuit is a circuit that has a pair of terminals on the input and output side. Two port circuit is used frequently on communication system network, control system, power system, and electronic circuit. Two port circuit is pictured as follows: Picture 1 A= Terminal C= Positive pole E= Blackbox B= Negative pole D = Port Requirement of a two port circuit is where the circuit has to be to be reciprocal and symmetrical. A circuit is called reciprocal whenever the voltage measured on port 2 against current on port 1 is equal to voltage measure on port 1 against port. The other requirement is where there is no dependent source on a reciprocal circuit. While a circuit is said to be symmetrical if input impedance is equal to output impedance. Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 17

Analysis of a two port circuit is based on the relationship between current and voltage on a network terminal to get the network parameter. Two port parameter can be categorized as: a. Admittance parameter (Y) b. Impedance parameter (Z) c. Hybrid parameter (h) d. Transmission parameter (abcd) e. Inverse transmission parameter f. Inverse-hybrid parameter(g) Admittance parameter can be obtained by writing the current equation as a function of the network voltage. I 1 Y 11 V 1 Y 12 V 2 I 2 Y 21 V 1 Y 22 V 2 I 1 Y 11 I 2 Y 21 Y 12 V 1 Y 22 V 2 Impedance parameter can be obtained by writing the terminal votlage equation equation as a function of the network current. V 1 Z 11 I 1 Z 12 I 2 V 2 Z 21 I 1 Z 22 I 2 V 1 Z 11 V 2 Z 21 Z 12 I 1 Z 22 I 2 Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 18

Relationship between two port circuits is called interconnection, there are 3 types of interconnection on two port circuits which are : 1. Series connected interconnection 2. Parallel connected interconnection 3. Cascade connected interconnection Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 19

III. EXPERIMENT TOOLS a. 1 Power Source b. 2 Amperemeter DC c. 2 Voltmeter DC d. Loads e. Cables IV. EXPERIMENT CIRCUIT A 1. Admittance parameter I1 P + - A1 + R3 Q I2 - + B A2 + V1 V2 R1 R2 - - S + V - R Picture 2 Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 20

2. Impedance parameter I1 + A - - R3 + V1 V V - R1 R2 I2 A + + V - Picture 3 V. EXPERIMETN PROCEDURE A. Admittance Parameter 1. Arrange circuit based on picture 4.2 2. Connect point B with R, and point S with P 3. Give power source to V1 and reverse the polarity of A2 4. Turn on Power supply. Record current I1 and I2 for every voltage increase of V1 5. Return power source to position zero(0), turn off power supply Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 21

6. Connect point A with R and S with Q 7. Give power source to V2 and reverse polarity of A1 and A2 8. Turn on power supply. Record current I1 and I2 for every voltage increase of V2 9. Return power supply to position zero(0), turn off power supply B. Impedance Parameter 1. Arrange circuit based on Picture 4.3 2. Give power source to V1 3. Turn on power supply. Record voltage V1 and V2 for every increase of I1 4. Return power source to position zero(0), turn off power supply 5. Give power source to V2 6. Turn on power supply. Record value of current V1 and V2 for every increase of I2 7. Return power source to position zero(0), turn off power supply VI. Questions and Assignments 1. Explain what is meant by two port circuit? 2. Explain the reason a two port circuit is needed in electric circuit analysis? 3. Create hybrid matrix, inverse hybrid, transmission and inverse trasnmission from experiment circuit! Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 22

MODULE VII AC CIRCUIT I. OBJECTIVE 1. Analyze the difference between AC and DC 2. Analyze AC circuit 3. Analyze the properties of active and passive elements on an AC circuit 4. Solve current and voltage equation of an electrical circuit with AC source 5. Able to apply laplace equation to solve a simple electrical circuit equation II. BASIC THEORY 1. Alternating Current ( AC ) Alternating current in general is back and forth current, scientifically the meaning of AC is an alternating current in terms of polarity and its magnitude over time. Generally, AC chart is illustrated in the form of a sinusoidal chart: The following factors are what differentiates between AC and DC: Polarity Frequency Power Power Factor Generation Property of L and C element Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 23

2. Inductor An inductor or reactor is a passive element (mostly torus shaped) that can store energy in magnetic field that is induced by the electrical current passing through it. The ability of the inductor to store energy is determined by its inductance, in unit Henry. Usually an inductor is a conducting wire that is formed into coil, the coil helps to make a strong magnetic field inside the coil due to Faraday s law of induction. 3. Capasitor Capacitor is an electrical component commonly, in physical terms, made from two conductors that are separated by an isolating material or dielectric. Capacitance is a measure of the capacitor s ability to store energy in electric field. Capacitance is expressed in Farad. 1 Farad describes the capacitor s ability to store 1 coulomb of electric charge whenever 1 volt of voltage is applied. 4. Power on AC circuit Active Power (P) Is power used to produce actual energy used Reactive Power (Q) Is power that appears due to presence of inductive and capacitive components Apparent Power (S) Is power that is generated and transmitted by power plants and is the result from multiplication between rms voltage and rms current in a network. 5. Laplace Transform Laplace transform is a technique to simplify problem in a system that has an input and output by doing transformation from one domain to another. This method is used in analyzing AC circuit to solve current and voltage equation. III. EXPERIMENT TOOLS Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 24

a. b. c. d. e. f. AC power supply Variable capacitor Variable inductor Variable resistor AC Voltmeter Cables = 1 piece = 1 piece = 1 piece = 1 piece = 2 pieces IV. EXPERIMENT CIRCUIT V. EXPERIMETN PROCEDURE 1. Arrange experiment circuit based on picture on experiment circuit 2. Record voltage value measured on Voltmeter 3. Repeat step 2 with different inductance and capacitance values VI. QUESTIONS AND ASSIGNMENTS 1. What will happen if capacitor and inductor are used with DC source? Explain! 2. Find the value of circuit time function by using second order equation! Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 25

MODULE VIII 3 PHASE CIRCUIT I. O BJECTIVE 1. Understand the definition of phase and polyphase. 2. Know 3 phase system configuration: wye connection and delta connection. 3. Express connections needed in 3 phase load circuit. 4. Differentiate symmetrical load and asymmetrical load. Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 26

5. Determine current on phase channel for asymmetrical load. 6. Know wye-delta conversion. II. BASIC THEORY Phase represents a change in voltage or current versus time represented in the form of an angle. In an electrical system, it is commonly used for three-phase circuit on the transmission and distribution of power. Three phase circuits are used by taking into account the economic aspect and the optimization of the electrical system. In the generation of three phase requires a three-phase AC generator. Here is a picture of a three-phase AC generator : Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 27

Three-phase circuit has two configurations, the star circuit and delta circuit. A. Delta connection In the delta circuit, the three impedances of the load is connected in series with each other. The three phase line are each connected by a node between the two loads. If all three phase loads of the three phase are identical, this is called symmetrical load. If the three loads are different, it is called asymmetric loads. In delta connection, line voltage and phase voltage has the same value, then Vline = Vphase. But the line currents and phase currents are not equal, and the relationship between the two currents can be obtained by using Kirchoff's law, so Iline = 3 Iphase. B. Wye connection In a star load circuit, the end of the three loads from each phase are connected to a single node where the neutral wire is connected. And at the other end of the three loads of each phase is connected with line which is the in/out line current (A, B, & C). Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 28

If the load value of each phase of a three phase is identic (same value and angle), therefore this is called a symmetrical load. And if the values are different it is called asymmetrical load. On a Wye connection, line current and phase current have the same value, therefore Iline = Iphase. But line voltage and phase voltage are not the same because Vline = 3 Vphase. Delta-Wye Conversion A delta circuit can be converted to a wye(star) circuit, and vice versa. The conversion method is by using the formula below. Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 29

III. EXPERIMENT TOOLS: a. 1 set 3-Phase Power Supply b. 1 set Transformer Circuit c. 4 pieces Amperemeter d. 1 piece Multimeter e. 3 pieces Variable Resistor f. 1 set Connector Cable Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 30

IV. EXPERIMENT CIRCUIT DIAGRAM Delta Connection Wye Connection V. EXPERIMENT PROCEDURE: VOLTAGE AND CURRENT MEASUREMENT ON DELTA CONENCTION Experiment 1 1. Arrange delta connection experiment circuit ( picture 5) with R1 = R2 = R3 = 220 ohm (symmetrical). Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 31

2. Measure line current IL on the three phase line and phase current Iph on three phase resistors using an ampere meter. 3. Measure line and phase voltage by using a multimeter. 4. Compare line current and phase current. Experiment 2 1. Arrange asymmetrical experiment circuit by replacing the value of R3 to 110 ohm. 2. Measure phase current and line current. 3. Measure phase voltage and line voltage. 4. Compare line current with phase current. VOLTAGE AND CURRENT MEASUREMENT ON STAR CONNECTION Experiment 1 1. Arrange wye connection circuit (Picture 6), with R1 = R2 = R3 = 220 ohm (symmetrical). 2. By using amperemeter, calculate line current Il and phase current Iph, and also neutral current In. 3. With multimeter, calculate phase voltage Vphase and line voltage Vline (voltage between phases). Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 32

4. Compare line voltage and phase voltage. Experiment 2 1. Arrange asymmetrical experiment circuit by replacing the value of load R3 to 100 ohm. 2. Calculate current on each phase, neutral current, phase voltage and voltage between phases. VI. QUESTIONS AND ASSIGNMENTS A. Delta Connection 1. Write the relationship between line current and phase current and between line voltage and phase voltage in a symmetrical delta connection! 2. What happens if one of the phases is removed from the delta connected circuit? 3. What happens if two phases are removed on a delta connected circuit? 4. What happens if one of the lines is removed on a delta connected circuit? B. Star Connection 1. Write the relationship between line current and phase current and between line voltage and phase voltage in a symmetrical star circuit! Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 33

2. What happens if the neutral line wire on an asymmetrical star circuit is removed from the circuit? 3. Draw the phase voltage vector diagram when the neutral wire is removed from the circuit! Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 34

MODULE 9 POST TEST Posttest is the final test regarding material that have been tested in Electric Circuit Practicum. All practicants are obligated to join the post test because this is part of scoring component. Time and place of posttest will be informed later. Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 35

Referensi - Johnson, David E. Electric Circuit Analysis.1997. Prentice Hall - Ramdhani, Mohammad. RANGKAIAN LISTRIK. 2008. Penerbit Erlangga - dan sumber buku lain Laboratorium TTPL Departemen Teknik Elektro FTUI 2016 Laboratorium, Tegangan Tinggi dan Pengukuran Listrik 36