The document discusses the design and simulation of several components for a relay menu including: 1. Interfacing an LCD and keyboard 2. Design and simulation of a zero crossing detector (ZCD) 3. Design and simulation of measuring voltage magnitude

1.  Design and programing of Relay Menu
 Interfacing LCD And Keyboard
 Design and Simulation of ZCD
 Design and Simulation of Measurement of Voltage Magnitude
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2. • Interfacing of LCD.
• Interfacing of Keyboard.
• ON/OFF Control.
• Reset.
• Menu.
• UP/DOWN/LEFT/RIGHT for navigation.
• Menu Consist of
• MTA Setting.
• Zone 1, Zone 2, Zone 3 impedance setting.
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3. • Zero crossing detector(ZCD) is a voltage comparator that switches the output
between +Vsat and –Vsat when the input crosses zero reference voltage.
• Working of ZCD can be easily understood if you know the working of a basic op
amp comparator.
• In ZCD, we are setting one of the inputs as zero i.e. zero reference voltage.
• The output is driven into –Vsat when the input signal passes through zero to
positive direction.
• Conversely, when input signal passes through zero to negative direction, the
output switches to +Vsat.
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Multisim 13 VBB StudioProteus 8

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8. • Output wave from ZCD for Current input is square wave
with 50Hz frequency
• Output wave from ZCD for Voltage input is square
wave with 50Hz frequency
• Output magnitude of ZCD is equal to VCC (3.56v, 5v,
12v)
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9. • Current sensor is used to get corresponding voltage output and wave.
• From the output wave we will get current zero crossing and magnitude.
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10. • High voltage is converted into low voltage by step down transformer.
• Analog voltage converted into Digital by ADC.
• Voltage magnitude is found by sampled digital value.
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11. • From the ZCD we will get square wave for current and voltage zero crossing.
• The time gap between this 2 output wave of ZCD is found.
• From the time interval Power factor is calculated.
5/8/2014Electrical Department PES University