Live Line Maintenance

PRESENTATION ON

LIVE-LINE MAINTENANCE

Submitted by:- NAME - GAURAV KUMAR PROGRAMME - B.TECH EEE

INDEX

INTRODUCTION HISTORY BASIC TERMS USED

a) Barehand Technique b) Conductive Clothing c) Grounded d) Hazard e) Hotstick Technique f) Job Supervisorg) Min Approach Distanceh) Nonconductive Rope i) Safety j) Worker

POSITIONING OF WORKERS WORKERS SWUNG DIFFERENT WAYS OF LINE MAINTENANCE GENERAL PRECAUTIONS REFERENCES

INTRODUCTION

The term live-line maintenance includes maintenance activities using the hot stick or the bare hand technique.

Fig 1.1:- Hotstick technique Fig 1.2 :- Barehand technique

Live-line maintenance is a procedural activity and does not include such activities as switching, climbing inspection, conductor stringing.

Maintenance activities performed on energized conductors or equipment with a phase-to-phase voltage exceeding 600 volts by the hotstick technique or 69 kV by the barehand technique.

In electrical engineering, live-line working is the maintenance of electrical equipment, often operating at high voltage, while the equipment is energized.

Fig 1.3 :- Hotstick method Fig 1.4 :- Barehand method

HISTORY

In 1916, a tool that was known as an “electrical hook” was introduced in Atlanta. This was essentially a spring-type clamp for tapping energized circuits.

In 1959, live-line tools with fiberglass poles were introduced. The fiberglass consists of layers of resin coated glass fibers wound around and laid lengthwise over a plastic foam core. It is highly resistant to moisture absorption and damage and can maintain 345-kV, 500-kV, and 765-kV transmission lines.

Fig 1.5 :- Electrical hook

34kV

220kV

110kV

22kV

66kV

Live-line tools were first accepted for work on lines up to 34 kV, but many linemen were hesitant to perform operations on this voltage and because of fear so they switch to -

BASIC TERMS USED

Barehand Technique - Live-line work performed by placing the worker at the same potential as the conductor.

Conductive Clothing - Metallic protective clothing worn by electrical workers.

Grounded - Connected to earth or to some conducting body that serves in place of the earth.

Fig 1.6 :- Clothing

Hotstick Technique - Live-line work performed by a worker placed at ground potential.

Hazard -Anything which can potentially endanger personnel and impair safe working conditions.

Nonconductive Rope - A flexible rope of twisted or braided synthetic polymer fibers maintained in a clean dry condition for use in conjunction with live-line maintenance.

Fig 1.7 :- Nonconducting rope

Job Supervisor - Any person authorized to request, receive, and release Clearances and Orders.

Min Approach Distance - The minimum working distance from energized conductors and equipment for personnel.

Safety - The art of performing any activity in an accident-free manner.

Fig 1.8 :- Safety Fig 1.9 :- Safety hook

Worker - Any person authorized to inspect, service, repair, or otherwise be in contact with equipment.

Fig 1.10 :- Worker

Total 9 wears during high voltage operation

POSITIONING OF WORKERS

INSULATED BOOM

Where, DA = Distance between the worker envelope and uninsulated truck and insulated boom componentsE = Worker envelope = 4 foot radiusD = Greater than or equal to the minimum electrical approach distance

Fig 1.11

INSULATED

LADDER

WORKERS SWUNG

Where, DT = Total minimum electrical approach distance with worker in the envelope.E = Worker envelope = 4 foot radiusD = Greater than or equal to the minimum electrical approach distanceFig 1.12

DIFFERENT WAYS OF LINE MAINTENANCE

Fig 1.13 :- Helicopter mode

Fig 1.14 :- Swinging and climbing mode

GENERAL PRECAUTIONSCalculation of minimum approach distances should be taken into account. Transmission systems are often fitted with coordinated protection devices which are circuit breakers that automatically attempt to remake a circuit after a fault.

An electric arc is extremely bright, including in the ultraviolet, and can cause arc eye, a painful and potentially blinding condition. Workers may be provided with appropriately tinted goggles that protect vision in the event of a flash.

It is usually required that more than one worker be present on site when working on live equipment above a specified voltage.

The work may be postponed if adverse weather conditions such as lightning or rainfall.

REFERENCES

ALL THE TOPICS ARE TAKEN FROM:-

1. Internet source