Electricity need Need of earthing- power installations and lightning protection The lifetime of earthing depends climate causing corrosion Corrosion occurs due to electrochemical process in soil or due to stray currents in earth also type of soil affects on it.

1. Dr. Babasaheb Ambedkar Technological University
Submitted by
SHIVANI M. SHETE
20140248

2. -Under guidance of : Prof. Anish Salvi

3.  Introduction
 Lightning Protection Overview
 Need to study effect of climate on earth electrodes
 Climatic factors that affects earth electrodes
 Earths resistivity: -Type of soil affects resistivity
Effect of moisture and dissolved salts
on resistivity.
Effect of temperature on earths resistivity.
 Case study in Polnad, south China, North Africa
 Case study in DBATU
 Conclusion

4.  Electricity need
 Need of earthing- power installations and lightning
protection
 The lifetime of earthing depends climate causing
corrosion
 Corrosion occurs due to electrochemical process in
soil or due to stray currents in earth also type of soil
affects on it.

5. Lightning protection overview

6. NECESSARY OF GOOD EARTHING
POWER SYSTEM STABILITY AND CONTROL
TO AVOID RESULTS OF BAD EARTHING
INITIALLY INSTALLED GROUNDING SYSTEM HAS LOW
RESISTANCE IN CORROSIVE SOIL

7.  SOIL RESISTIVITY
 VOLUME OF WATER COTENT IN SOIL
 PH OF SOIL
 TEMPERATURE OF THE ENVIRONMENT

8.  It is measured in ohm-cm.
 earth resistivity is required to indicate the degree
of corrosion to be expected in ground pipelines.
 In general, as the resistivity values are low tend to
increase corrosion.
 Earth resistivity changes because of following:
 Type of soil affects resistivity
 Effect of moisture and dissolved salts
 Effect ot temperature on earths resistivity

9.  Type soil affects resistivity:
As the soil type changes the resistivity os soil also
changes. From the results it is observed that surface
limestone has maximum resistivity. Whereas, surface soil
or loam has minimum resistivity.
Fertile and infertile soil.
 Effect of moisture and dissolved salts on
resistivity:
Resistivity decreases with moisture and dissolved salts. Pure
water has infinitely high resistivity and naturally occuring
salts lowers the resistivity.

10.  Effect of temperature on earths resistivity:
Increase in temperature decreases the resistivity. Up to 80 ℃
as temperature increases resistivity increases as a result
corrosion increases.
Beyond 80 ℃ up to 100 ℃ there is not much effect of
increase in temperature.
Fig : seasonal variations in earths resistivity

11. LPI has carried out tests in different regions of the
world to know how the climatic conditions may
affect corrosion earth electrodes.
The tests are carried out in:
 Poland
 South of china
 North Africa

12.  Two regions chosen Mielno and Inowroclaw.
 Three types of electrodes used.
 Comparison between selected regions.
 Results shows change in thickness and also
electrode covered with corroded layer.
 Which type of electrode should be preferred.
South of china:
 110kv substation and 220kv transmission line
tower is selected for test in Ghanzou.

13.  Zinc galvanised steel electrode is used.
 Tests is carried out for 10 years of installations.
 In 110kv substation- results shows the corrosion rate of
0.25mm/year.
 In 220kv line transmission tower – results shows as
0.3mm/year.
 Climate in Ghanzou- high rain, low sunshine.
North Africa:
 Libya and Sudan places selected for carrying tests.

14.  Test carried out where power system installations is under
construction and results shown after 4 and 6 months.
 Very high degradation occurs.
 Vast variation in temperature occurs in North Africa hence the
destruction is much more in short time.

15.  In summer season- extreme temperature
 In rainy season- extreme rain occurs, as a result
water table increases.
 The type of soil ( in fertile).

16.  Topic suggests how climatic conditions affects on
earth elecgrodes.
 Corrosion development of steel zinc galvanized
electrode
 Mostly prefer copper coated steel electrodes.
 Corrosion rate in faster in China due to high rainfall.
 Not to install zinc coated steel earth electrode.