FIELD OF THE INVENTION

The present invention generally relates to a method of protection for medium voltage overhead transmission line supported on poles and providing electrical power to utilities installed on remote locations against lightning strokes. More particularly, the invention relates to a spike-shaped earthing device to protect from lightning strokes the high voltage overhead transmission lines supported on multiple poles and extending to long distance to feed power to utilities at remote locations.
BACKGROUND OF THE INVENTION
It is known that the high-voltage Over Head Long Single Circuit Transmission Lines supported on multiple poles for feeding power to utilities at remote stations are often susceptible to tripping during rains accompanied by the Lightning Stroke, and frequently causes interruption of power supply. The intensity of the lightening strokes sometimes are so high that they strike at poles leading to damages to the equipment installed over the poles, the conductor and ultimately results in tripping.

Since such transmission line is not protected by earth-wire, such as those placed on transmission line towers, hence prevention of outage of the equipment is not controllable.
The present inventors recognized that the basic principles based on which a lightening conductor works are :
1. Electricity travels best through a path of least resistance.
2. Static charges always accumulate at the pointed surface of a conductor and reside on the outer surface.
3. Transmit discharge of electric current occurs between a negatively charge centre and positively charged region in the form of lightning flash.
4. Opposite charges attract each other.
Inductive Coupling is a magnetic field transformer effect between lightning and the conductors. A lightning discharge creates a very high current flow and this current creates electro magnetic field around. If power passes through this

magnetic field, voltage is induced in the cable. This frequently occurs when, lightning discharges close to overhead power lines. It is not just lightning strikes from cloud to ground which can induce these voltages, cloud to cloud strikes can also induce similar effects albeit to a lesser extent generally.
Capacitive Coupling: where long transmission lines are well isolated from the earthed wire, they can rise to high voltages due to capacitance between them and the charged thunder cloud. If the voltage on the line rises beyond a breakdown strength of the devices at either end, then only the damage will result.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a spike-shaped earthing device to protect from lightning strokes the high voltage overhead transmission lines up to 33 KV supported on multiple poles and extending to long distance to feed power to utilities at remote locations which is capable of being installed on the poles to neutralize lightning by providing a conductive path.

A further object of the invention is to propose a spike-shaped earthing device to protect from lightning strokes the high voltage overhead transmission lines supported on multiple poles along with the associated equipments and utilities.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows the damaged utilities connected to a prior art overhead transmission line due to lightning.
Figure 2 - shows prior art transmission lines isolated by earth-wire to eliminate damage due to lightning, wherein high voltage pick-up due to capacitance between them and charged thunder cloud.
Figure 3 - shows a prior art high voltage over-head transmission line supported on poles.
Figure 4 - shows pole-supported high voltage over-head transmission line provided with a spike shape earthing device according to the invention.
Figure 5 - shows the complete assembly along with electrode components for earthing.

BRIEF SUMMARY OF THE INVENTION
According to the invention, the base arm of prior art V-Cross on the pole support is retained un-disturbed. A new base for Spike earthing is developed keeping in view the safety clearances as per IER 1956. A new base frame is then mounted on the pole using a clit arrangement of Gl fastener.
Using 20mm of diameter of Gl pipe, a pointed electrode arrangement is made and mounted over the pre fabricated V Cross arm.
This new electrode is firmly earthed with the existing pole structure to achieve an earth resistance below 10 ohm as per IS 3043 for transmission line utility.
The spike earthing device when fixed over high voltage over-head transmission line, increases the system reliability. Adopting basic principle of lightning as it strikes the Highest Point of Area and after proper dissipation gets effectively earthed.
The transient discharge of electric current that occurs between a negative charge center and a positive charged region is a lightning flash. A typical flash is made

up of or more discharge components or pulses, with each consisting of a negative leader stroke and a positive return stroke.
The spike-shape earthing device safe guard the poles and its equipments during Lightning. Using the basic principles of engineering and calculations, the device is constructed as per IER 1956 guidelines.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Existing 33 KV transmission lines as shown in Fig.l, erected on poles suffers from adequate earthing device in prior art, wherein the challenge for installation of spike earthing has been felt.
Transmission poles (P) comprising V-cross arm (1), carrying two lines of the three phase system, base arm (2) carrying the third line has been modified under the process of this invention.
The new base frame (3) has been developed and mounted on the pole (P) using basic clit argument by GI fastner (5), using 40 mm diameter of GI pipe a pointed

electrode arrangement (4) has been made, which is mounted over the prefabricated V-cross arm.
The new electrode is solidly earthed with the existing pole structure having an earth resistance of less than 10 ft as shown in Fig. 4.
Adopting the basic principle of lightening as it strikes the highest point of area, the spike electrode pointer is mounted at higher level than the three phase power line as shown in Fig. 5.

WE CLAIM,
1) A spike earthing system on single circuit transmission line on poles for
feeding power to the utilities at remote stations comprising :-
A) Base frame
B) Clit arrangement for fixing by GI fastener
C) GI pipe (20 mm dia)
D) Pointed Electrode arrangement
E) Solid earthing with the pole structure (resistance less than 10 ohm)
2) The earthing system as claimed in claim 1, wherein, a base frame attached with the pole to hold the spike electrode without affecting the existing V-cross arm as in the prior art.
3) The earthing system as claimed in preceding claims, wherein, clit arrangement for fixing the frame by GI fastener on the pole.
4) The earthing system as claimed in preceding claims, wherein, GI pipe forming the basic part of the spiked electrode.

5) The earthing system as claimed in preceding claims, wherein, pointed electrode arrangement is the collector of charges in the system.
6) A spike shaped electrode characterized by a pointed tip for accumulation of charges and subsequent discharge of lightening current for protection against lightening stroke.