Created by Mohan K M, Ganesh C, Yerriswamy Technology used: Microsoft power point, Excel, Multisim, Proteus, AutoCAD, Solid edge, Arduino. As a final year project in PESIT Bangalore
- 1. By: Mohan K M, Ganesh C, Yerriswamy A Microcontroller Based
Mho Relay Under the guidance of Mrs. Jyothi T N
2. INTRODUCTION 6/23/2014Dept. EEE PESIT 3. 6/23/2014Dept. EEE
PESIT 4. 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
occurrence 2. Sensing of fault 3. Isolation of faulted section Unit
Generator-Tx zone Bus zone Line zone Bus zone Transformer zone
Transformer zone Bus zone Genera tor ~ XFMR Bus Line Bus XFMR Bus
Mot or Motor zone 6/23/2014Dept. EEE PESIT 5. Primary protection
Backup protection Classification of relays based on application 1.
Under voltage, under current & under power relays 2. Over
voltage, over current & over power relays 3. Directional or
reverse current relay 4. Differential relay 5. Distance relay TYPES
OF PROTECTION 6/23/2014Dept. EEE PESIT 6. Distance relay 1.
Impedance relay 2. Mho relay 3. Reactance relay Mho relay is a
distance relay with inherent directional element. 6/23/2014Dept.
EEE PESIT 7. It has 3 zones of protections 1. Zone 1: 80-85% of
protected line 2. 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 6/23/2014Dept. EEE PESIT 8. Zone 1 Zone 2
Zone 3 6/23/2014Dept. EEE PESIT ZseenI1 Z1Iseen>I2
Z2setIseen>I3 Relay 9. Zone 1: Instantaneous Zone 2: 0.5 sec
Zone 3: 1 sec TRIPPING TIME 6/23/2014Dept. EEE PESIT 10. BLOCK
DIAGRAM VOLTAGE INPUT CURRENT INPUT ZERO CROSSING DETECTOR
MICROCONTROLLER KEYPAD CONTACT LCD ANALOG TO DIGITAL CONVERTER
VOLTAGE INPUT CURRENT INPUT 6/23/2014Dept. EEE PESIT 11. Current
sensor is used to get corresponding voltage output and wave
respectively. The output wave is sampled using ADC. From the
repetitive measurement calibration of digital samples into
corresponding current magnitude is achieved. 6/23/2014Dept. EEE
PESIT 12. 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. 6/23/2014Dept. EEE
PESIT 13. Multisim 13 MATLAB 2013Proteus 8 6/23/2014Dept. EEE PESIT
14. CURRENT AND VOLTAGE MEASUREMENT CIRCUIT Current Measurement
circuit Voltage Measurement circuit 6/23/2014Dept. EEE PESIT 15.
OUTPUT OF MEASUREMENT CIRCUIT Current Measurement circuit output
Voltage Measurement circuit output 6/23/2014Dept. EEE PESIT 16.
Curve fitting to make current measurement Accurate 6/23/2014Dept.
EEE PESIT 17. Current Measurement Current in Microcontroller
Current by Ammeter -0.441 0 -0.361 0.25 -0.291 0.43 0.071 0.82
0.4471 1.22 0.877 1.62 1.3871 2.1 1.96 2.57 2.5471 3.13 3.3471 3.86
3.7871 4.23 4.3671 4.82 4.9471 5.3 6.0371 6.25 6.9071 7.05 8.6471
8.75 10.461 10.45 12.421 12.47 13.651 13.87 14.671 15.05 After
Curve Fitting 0.0717 0.2235 0.3454 0.8523 1.2446 1.6257 2.0633
2.5758 3.1222 3.8677 4.2670 4.7799 5.2845 6.2455 7.0451 8.6553
10.0992 11.1802 11.2752 10.6593 6/23/2014Dept. EEE PESIT 18.
DESIGNING OF MAIN POWER CIRCUIT 6/23/2014Dept. EEE PESIT 19.
DESIGNING TOOLS Auto CAD 2010 SOLID EDGE 18 6/23/2014Dept. EEE
PESIT 20. MODEL DESIGNED IN SOLID EDGE 6/23/2014Dept. EEE PESIT 21.
6/23/2014Dept. EEE PESIT 22. ADVANTAGES OF MICROCONTROLLER BASED
RELAY 1. Flexibility 2. High reliability 3. Fast operation
6/23/2014Dept. EEE PESIT 23. CONCLUSION From the observed
performance of several tested cases, it can be seen that the model
works satisfactorily and gives excellent results. Many tests have
been conducted successfully. These relays are compact, reliable and
flexible over conventional relays. The relay algorithm computation
speed is increased and accuracy is not compromised. The relay also
provides improved performance and user friendly human interface.
6/23/2014Dept. EEE PESIT 24. REFERENCE  Power system engineering
by R.K Rajput page no 912 to 946.  Text book on power system
engineering by A.chakrabarthi, M L Soni, P V Gupta, U S Bhatnagar,
revised edition, Dhanpat Rai publishers  Power system protection
and switchgear by Bhuvanesh A Oza, Nirmal kumar C Nair,Rashesh P
Mehta,Vijay H Makwana  IEEE Tutorial Course, Microprocessor
Relays and Protection Systems. The Institute of Electrical and
Electronics Engineers,INC., 1987  IEEE Tutorial Course, Computer
Relaying, The Institute of Electrical and Electronics Engineers,
INC., 1979.  V. Gurevich, Electric Relays Principles and
Applications, Taylor & Francis Group, LLC, 2006.  K. M.
Silva, W. L. A. Neves and B. A. Souza, "EMTP Applied to Evaluate
Three- Terminal Line Distance Protection Schemes," International
Conference in Power System Transients (IPST'07) in Lyon, France,
pp. 1-6, June 4-7, 2007. 6/23/2014Dept. EEE PESIT 25.
6/23/2014Dept. EEE PESIT Ganesh C Yerriswamy A Mohan K M