MICROCONTROLLERBASED
DIRECTIONAL MHO RELAY
Presented by:
Ganesh C
Mohan K M
Yerriswamy A
04/10/2023Electrical Department PES University
INTRODUCTION
04/10/2023Electrical Department PES University
POWER SYSTEM PROTECTION
• Main idea of protection is to remove faults as quickly as possible mean while maintains the system stability.
• Under abnormal operating conditions protection is necessary for Safety of electrical equipments. Safety of human personnel.
• Sequence of events in relation with a fault 1. Fault occurrence2. Sensing of fault3. Isolation of faulted section
Unit Generator-Tx zone
Bus zoneLine zone
Bus zone
Transformer zone
Transformer zone
Bus zone
Generator
~XFMR Bus Line Bus XFMR Bus Mot
or
Motor zone
04/10/2023Electrical Department PES University
• Primary protection
• Backup protection
Classification of relays based on application1. Under voltage, under current & under power relays2. Over voltage, over current & over power relays3. Directional or reverse current relay4. Differential relay5. Distance relay
TYPES OF PROTECTION
04/10/2023Electrical Department PES University
Project focus
• Distance relay1. Impedance relay2. Mho relay3. Reactance relay
Mho relay is a distance relay with inherent directional element.
04/10/2023Electrical Department PES University
• It has 3 zones of protections1. Zone 1: 80-85% of protected line2. Zone 2(minimum): 120% of protected line
Zone 2(maximum): < protected line + 50% of shortest second line
3. Zone 3F: 1.2(protected line + longest second line) Zone 3R: 20% of protected line
MHO RELAY
04/10/2023Electrical Department PES University
• Zone 1: Instantaneous
• Zone 2: 0.5 sec
• Zone 3: 1 sec
TRIPPING TIME
04/10/2023Electrical Department PES University
BLOCK DIAGRAM
VOLTAGE INPUT
CURRENT INPUT
ZERO CROSSING DETECTOR
MICROCONTROLLER
KEYPAD
CONTACT
LCD
ANALOG TO DIGITAL
CONVERTER
Yset<Ymessared*cos()
REQUIREMENTS
• ATMEGA 328 MICRO CONTROLLER (Arduino)• MULTISIM/PROTEUS SIMULATOR• Current sensor• Voltage sensor• ZCD (zero crossing detector)• Breaker/contactor• Electrical load
04/10/2023Electrical Department PES University
04/10/2023Electrical Department PES University
Reference• [1] IEEE Tutorial Course, “Microprocessor Relays and Protection Systems”. The Institute of Electrical
and Electronics Engineers,INC., 1987
• [2] IEEE Tutorial Course, “Computer Relaying”, The Institute of Electrical and Electronics Engineers, INC., 1979.
• [3] V. Gurevich, Electric Relays Principles and Applications, Taylor & Francis Group, LLC, 2006.
• [4] "MiPower Power System Analysis Software Package- User Manual," Power Research and Development Consultants Pvt Ltd., Bangalore, India.
• [5] Bayindir R., Sagiroglu S., Colak I., An intelligent power factor corrector for power system using artificial neural Networks, Electric Power Systems Research 79 (2009) 152–160.
• [6] Azcondo F. J., Diaz F. J., Branas C., Casanueva R.,Microcontroller Power Mode Stabilized Power Factor Correction Stage for High Intensity Discharge Lamp Electronic Ballast, IEEE Transaction on Power Electronics, Vol. 22, No. 3, 2007, 845-853.
• [7] Sagiroglu S., Colak I., Bayindir R., Power factor correction technique based on artificial neural Networks, Energy Conversion and Management 47 (2006), 3204–3215.
04/10/2023Electrical Department PES University
THANK YOU
04/10/2023Electrical Department PES University
Time schedule2
7th Jan • Selection of
Project• Simulating
and Designing of Power factor measurement
15
th F
eb • Hardware
building and testing of ZCD
• Programming of measurement of Power angle
7th M
ar • Simulation
and designing of Voltage and current measurement
• Programming for measurement and ADC
29
th M
ar • Hardware
building and testing Relay
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