The document discusses surge currents, which are transient waves of high-magnitude current that occur in electrical circuits due to rapid changes in voltage or current, often caused by lightning strikes or sudden load changes. It outlines the causes, impacts, protection devices such as surge arrestors and semiconductor devices, and applications in both industrial and residential settings. Understanding surge currents and implementing appropriate protection measures are crucial to safeguarding electrical systems from potential damage.

1. GOVERNMENT POLYTECHNIC,SONEPUR
NAME- SHYAMASUNDAR MENDILI
BRANCH- ELECTRICAL ENGINEERING
REGD. NO- F22117002053
SEMESTER- 5TH
GROUP- 02
TOPIC- SURGE CURRENT

2. Introduction
What Is Surge Current ?
Reasons Of Occur Surge Currents
Protection Devices
Advantages Of Semiconductor Device
Applications
Conclusion
CONTENTS

3. INTRODUCTION
 In general, a surge is a transient wave of
current, voltage or power in an electric circuit.
 It’s a sudden, temporary flow of high-magnitude
current through an electrical circuit or device. It
occurs due to a rapid change in voltage or
current, often caused by lightning strikes.

4. What is surge current ?

Surge current is the “ current that raise
or fall from the normal rated value in the
short duration of time ’’these are the
instantaneous sharp impulse currents .

5.  Surge currents occur due to the lighting strikes.
 Surge current occur in the electrical machines
during their turn on condition.
 Surge current occur due to the sudden change in
the loads .
 Surge current occur due to the sudden variation in
the input voltage of the electrical machines.
 Surge current occur due to the rectifier filter
circuit.
CAUSES OF OCCUR SURGE CURRENT

6. PROTECTION DEVICES:
1.SURGE ARRESTORS
2.SEMICONDUCTOR DEVICES
 THYRISTORS
 TRIACS
 INDUCTORS
 NTC THERMISTORS

7. 1. Surge arrester
 Surge arrester protects the system from
lightning ,switching, electrical faults and other
transients voltage and surges while lightning
arrester are mainly used for lightning strikes.

8. Surge arrester

9. SEMICONDUCTOR DEVICES
THYRISTOR
TRIAC
INDUCTORS
NTC Thermistor

10. •Safety, reliability , and power quality.
•Cost for C.B and fuses can be reduced .
•Life of transformers extended.
•Reduced or eliminate wide area,
blackouts.
•Provide protection to T&D equipment.
ADVANTAGES

11. APPLICATIONS
1. Industrial application
Power supplies
Motor drive
Industrial control
system 2. Residential
application Home
appliances Computer
system
Home Entertainment

12. CONCLUSION
Surge currents can have devastating
effects on electrical systems and devices.
Understanding the causes and effects of
surge currents, as well as implementing
protection measures, is essential to
preventing damage and ensuring the
reliability of electrical systems.

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