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Geetanjali Institute of Technical Stuides,Udaipur
Branch/Sem:EE/VI Sem
Subject: Power System Instrumentation (6EE6.2A)
Faculty Name: Abhishek Sharma
UNIT -1
1. Define limiting errors. Derive the expression for relative limiting error.
2. Three resistors have following ratingR1=37Ω±5% R2=75Ω±5% R3=50Ω±5% Determine
the magnitude and limiting error in ohm and in percent of the resistance of these resistances
connected in series. What do you mean by viscosity.
3. Systematic errors can be classified as :
1. Instrument errors
2. Environmental errors
3. Observational errors
Discuss the above types of error giving suitable example
4. Define the following terms in the context of normal frequency distribution of data:
1. Mean value
2. Deviation
3. Average deviation
4. Standard deviation
5. variance
5. A capacitor C=1.0±1 micro farad is charged to a voltage 20±1 V, where errors are probable
errors. Find the charge on the capacitor and its probable error.
6. A voltmeter having a sensitivity of 1000 Ω/ V reads 100v on its 150V scale when connected
across an unknown resistor in series with a mili-ammeter. When mili-ammeter reads 5mA
calculate
A) Apparent resistance of unknown resistor (B) Actual resistance of unknown resistor
C) Error due to loading effect of voltmeter.
7. The measured value of a resistance is 111 ohm where is its true value is 110 ohm. Determine
absolute error of measurement and relative error.
8. The capacitance of a capacitor is specified as 205 & 195 percent by manufacturer. Determine
the limits of capacitance between which it is guaranteed.
9. Define Gaussian Error curve and Probable Error.
10. A 0.25A ammeter has a guaranteed occurrence of 1% of full scale reading The current
measured by ammeter is 5A. Determine the limiting error in percent.
UNIT 2
1. Explain the construction of wire wound strain gauge and derive the expression for the gauge
factor
2. Describe the different criteria for selection of transducers for a particular application
Geetanjali Institute of Technical Stuides,Udaipur
3. Describe the construction, principle of working and application of Hall Effect transducer.
4. The output of LVDT is connected to a 5V voltmeter through an amplifier whose amplification
factor is 250.An output of 25 mV appears across the terminals of LVDT when the core moves
through a distance of 0.5mm.Calculate sensitivity of the LVDT and that of the whole setup. The
mili-voltmeter scale has 100 divisions. The scale can be read to 1/5 of a division. Calculate the
resolution of the instrument in mm.
5. Define the digital transducer and explain its application of linear and angular displacement.
6. Describe the working and construction of resistance thermometers. Describe the material used
for RTDs along with their properties. Sketch their typical characteristic.
7. A single strain gauge having resistance of 120Ω is mounted on a steel cantilever beam at a
distance of 0.15 m from the free end. An unknown force F applied at the free end produces a
deflection of 12.7 mm of the free end. The change in gauge resistance is found to be 0.152 Ω.the
beam is 0.25 m long with a width of 20 mm and a depth of 3mm.the young’s modulus for steel is
200GN/m2.calculatethe gauge factor.
8. Explain following type of errors for a transducer
1. Scale error
2. Dynamic error
3. Noise and drift error
9. Draw and explain the construction and working principle of L.V.D.T. What are their advantages
and disadvantages?
10. What are the temperature transducers? Give their advantages, disadvantages and uses.
UNIT – 3
1. Define shielding and grounding. Write the different aspects of shielding and grounding.
2. Write short note on Instrumentation amplifiers.
3. Describe the function generator. Drawn the neat and clean diagram of function generator.
4. Explain sample and hold circuit. Draw its characters tics.
5. Explain the working principle of a function generator with block diagram.
6. Explain the circuit diagram of instrumentation amplifier and discuss applications merit and
demerit also.
7. Explain the construction and working of frequency to voltage converter suitable diagram.
8. What do you mean by isolation amplifier? Explain circuit diagram and application also.
9. What is shielding & grounding?
10. What is signal conditioning? Give the block diagram representation of DC and AC signal
conditioning.
UNIT – 4
1. What is power factor? Explain the causes of low power factor and methods of improvement of
power factor?
2. Explain the industrial metering and various types of industrial tariffs.
3. Describe the constructional detail and the working of a single phase induction type energy
meter.
Geetanjali Institute of Technical Stuides,Udaipur
4. Explain the different type of tariffs used.
5. How is measurement of energy done? Give the type of meters used in 1 and 3 phase system.
6. Give the diagram of modern electronics metering adopted in the industrial substation and
discuss its features
7. When two wattmeter method used to measurement of a power in 3 phase balanced circuit,
comment upon the reading of the two wattmeter under following conditions. Support your
answer by drawing phasor diagram. Assume that the circuit in star (Wye) connected.
1) When p.f. is unity
2) When p.f. is Zero lagging.
8. Explain the construction and working of the Ratio meter type frequency meter.
9. A 3 phase 500 V motor load has a power factor of 0.4 Two wattmeter connected to measure the
input. They show the input to be 30 Kw. Find the reading of each instrument.
10. Explain the testing of energy meters.
UNIT - 5
1. W hat i s C VT? Draw t he t heveni n’s equi val ent ci rcui t of C VT and ex pl ai n t he
t rans i ent s behavi or.
2. Describe the error of C.T. and also explain the burden of C.T.
3. Describe the working of capacitive voltage transformer.
4. Draw the equivalent circuit and phasor diagram of a current transformer. Derive the expressions
for ratio and phase angle errors.
5. Explain the transient performance of a C.T.
6. Explain the Wilson compensation method for reduction of errors in current transformer.
7. Discuss the major errors in Current Transformer
8. What are the major characteristics of the Current Transformer?
9. Explain the effect of the following on the performance of current transformers:
1) Change of primary winding current
2) Change of secondary burden
3) Change of frequency.
10. Explain the Wilson compensation method for reduction of errors in C.T.