Wonderful discussion during Skill development training with Site head Shri SKB Valli sir.
Transformer earthing connects the transformer's neutral or body to the earth, providing a safe path for fault currents to protect equipment and personnel, with primary types including Neutral Earthing (solid, resistance, reactance) for system stability and Equipment Earthing (body/tank) for safety, often using specialized Earthing Transformers (like Zigzag) in delta systems to create a neutral point and manage fault current levels.
Purpose of Transformer Earthing
Safety: Prevents electric shock to personnel by keeping metallic parts at zero potential.
System Stability: Provides a stable zero-potential reference point for the power system.
Fault Current Path: Offers a low-resistance path for fault currents to flow to the ground.
Protection: Allows protective relays to detect faults and operate effectively.
Overvoltage Control: Limits transient overvoltages during faults.
Types of Transformer Earthing
System Earthing (Neutral Earthing)
Solid Earthing: The neutral point is directly connected to the earth. Used for high fault currents, allowing fast fault clearance.
Resistance Earthing: A resistor is placed between the neutral and earth to limit fault currents, reducing damage and arc flash risks.
Reactance Earthing (Arc Suppression): A reactor is used to limit fault currents to a specified value, often balancing protection with equipment life.
Earthing Transformer (Grounding Transformer): Used in ungrounded systems (like delta) to create a neutral point for grounding, often with zigzag (inter-star) windings to handle fault currents and suppress arcs.
Equipment Earthing (Body/Tank Earthing)
Connects the metallic frame, tank, and other non-current-carrying parts to the earth, usually via a ground rod or plate, for personnel safety.
Key Components & Methods
Earth Electrode: A conductor (rod, plate, pipe) buried in the ground to provide the final connection to earth.
Zigzag Winding: A special winding in earthing transformers that creates a neutral point and allows for efficient fault current path, preventing flux buildup in the core.
Neutral Grounding Resistor (NGR): A resistor used in resistance earthing to control fault current magnitude.
Why Different Types?
Solid: For systems where large fault currents are acceptable for quick clearing (e.g., distribution systems).
Resistance/Reactance: For medium voltage systems where high fault currents could damage equipment or cause excessive arc flash.
Earthing Transformer: Essential for delta-connected systems (which lack a natural neutral) to enable ground fault protection and stability.
PROCEDURE FOR JOURNEY MANAGEMENT
ReplyDeleteThese Guidelines are for vehicles, which include the following:
• Buses used for transport
• Cars (employee own / hired)
• Heavy Vehicles
• Vehicles carrying Hazardous Goods
• Two wheelers
Hazards to Mitigate
ReplyDelete• Distracted driving • Malfunctioning/poorly maintained vehicle
• Driver impairment (fatigue) • Unsecured loads/ projectiles
• Driver inexperience • Other drivers
• Poor road conditions • Wildlife
• Communication failure (e.g. Mobile dead zones)
• Time of day (e.g. reduced visibility)
Minimum requirements of vehicle for use:
▪ Brakes (including hand brakes) should be in good working condition.
▪ Tyres including spare should be in good condition.
▪ Lights including the tail lamps provided on the vehicle should be functioning.
▪ Windshield wipers should be functioning.
▪ Horns including reverse horn should be operational and audible.
▪ The vehicle should be in neat & clean condition from both inside & outside.
▪ Necessary valid following documents should be available…
a. RC Book,
b. Insurance,
c. Road Tax,
d. Road permit,
e. Vehicle fitness certificate,
f. PUC &
g. Valid license to drive the respective vehicle
Two wheelers should be roadworthy (see Annexure 1- relevant points from the list) and should be regularly checked. The vehicle must meet the minimum requirements given below;
All Brakes should be in good working condition.
▪ Tyres including spares must be in good condition.
▪ All the lights must be functioning.
▪ Horns should be operational and audible.
▪ Vehicle must have Sari guard (for Motorcycles).
▪ Necessary following valid documents should be available…
✓ RC Book,
✓ Insurance,
✓ Road Tax,
✓ Road permit,
✓ Vehicle fitness certificate,
✓ PUC & Valid license to drive the respective vehicle
Vehicle & Transport Management.
ReplyDeleteDriver Standards
• All drivers must have undertaken a Government approved driving test and possess a legitimate vehicle driving license.
• All drivers must have an annual medical assessment in accordance with Periodical Medical examination.
• All drivers must undergo defensive driving training by an approved instructor before driving a company owned or leased vehicle.
• All professional drivers hired by the company must have a minimum of 3 years driving experience in a professional driving capacity and have a pre-employment driving assessment
Vehicle used to commute employees in the uneven / hilly roads, which evoke a high risk of vehicle toppling.
ReplyDeleteGreenko has extensively tried to ensure safe transportation system especially, when come to its employees.
Hazards related with Transportation Safety shall address the below but not limited to:
• Driving without authorization including non-availability of statutory documentation
• Driving under influence of alcohol / narcotic substance
• Reckless driving
• Over loading more than specified load limit
• Non-availability of preventive maintenance of vehicles
• Non-availability of equipment related in dealing with vehicle breakdown situation
• Not following Defensive Driving rules
• Generation of dust while movement in Ghat roads
• Driving on uneven road surface, skid situations and low illuminated areas.
Light Vehicles
• Definition: Any vehicle that has an unladen weight of less than 7500 Kg.
• Vehicles must be suitable for the intended purpose.
• Off-road type vehicles are not recommended for normal road and highway use, as their handling characteristics require special training for drivers. They should only be used where there is a requirement for off-road use or where the road surface conditions require a vehicle of this type.
• The following minimum standards will be applied when purchasing or leasing vehicles:
o Anti-lock Braking System (ABS)*
o Air bags (including passenger side)*
o Safety belts for all seats front and back. Retrofitted belts should be the same type supplied by the vehicle manufacturer or from an approved supplier and be fitted by a competent organisation
o High level brake light*
o Head restraints fitted to all seats*
All windows (doors, windscreen, rear of cabin) will be fitted with non-splintering safety glass that provides unimpaired vision i.e. no cracks etc.
o All pedals i.e. clutch and brake shall be fitted with rubber pads to prevent slippage
o Doors and locks shall be fully operable
o All vehicles to install speed governor (limit 80 kmph)*
o All vehicles to install GPS tracking device*
o All vehicles to carry a first aid kit and torch
o All vehicles must be fitted with portable a dry powder/ ABC fire extinguisher
o All vehicles will meet the emission standards of India (BSIV & above)
o All vehicles will meet the licensing requirements of India.
o Tyres must be suitable for the duty that the vehicle is normally used to perform. Tyre construction is to be:
▪ Small Passenger Cars - tread 4 ply (2 steel and 2 polyester), sidewall 1ply polyester e.g. Buick Sail
▪ Large Passenger Cars - tread 4 ply (2 steel and 2 polyester), sidewall 2 ply polyester. Single ply sidewall can be used up to tyre size 195/60 R 15 where 2-ply sidewall is unavailable or a manufacturer expressly recommends single ply.
Some larger vehicles require
Minibuses and Buses
ReplyDelete• There are modern minibuses of various capacities, some with 24 seats, and large buses available in most locations in India that are equipped with safety equipment including seat belts fitted to all seats. When purchasing, hiring or leasing these types of vehicles they should meet the standards for light vehicles where possible with the exception of air bags. ABS should be fitted wherever possible.
Selection of lease or hire contractors for minibuses and buses should be assessed for their standards of safety, maintenance and management. We must ensure drivers are properly trained and are medically fit. Drivers of long-term lease vehicles should be trained in defensive driving by a Greenko approved instructor.
At any moment the speed of the vehicles moving on the plant/project road shall not exceed 20 KMS / hour within the plant/project premises.
Safety Belt Use
• To assure the safety of all employees, safety belts shall be worn by the drivers and passengers in all vehicles owned, leased or rented by the company at all times. This also applies to the operation of privately owned or other vehicles if used in work related activities.
o Employees shall use the safety belts, properly adjusted and securely fastened when operating or riding in any vehicle so equipped. Belts must be adjusted so that they fit firmly around the body.
o Lap belts shall be properly secured in those vehicles equipped with automatic safety belt systems that require the lap portion of the belt to be manually secured.
o The driver of the vehicle is responsible for ensuring compliance by all occupants of the vehicle they are operating. Employees and expat families are responsible for ensuring that their visitors travelling in the vehicle use the seat belts.
o No person shall operate a work-related vehicle in which any safety belt in the drivers seating position is inoperable. No person shall be transported in a seating position in which the safety belt is inoperable.
o No person shall modify, remove, deactivate or otherwise tamper with the vehicle safety belts except for vehicle maintenance and repair.
o Employees who discover an inoperable safety belt shall report the defect to the appropriate supervisor. Prompt action will be taken to replace or repair the system.
o If a vehicle does not have seat belts in the rear seat, then the front passenger seat should be used where there is a seat belt fitted.
Pre-Check Safety Inspections
• Drivers shall conduct a visual and physical pre-check of vehicles prior to driving each day
o Key areas include:
▪ Tyre pressure including the spare
▪ Tyre condition - all tyres including the spare must have a minimum tread depth of 1.5mm over the whole tread pattern
▪ All lights
▪ Windscreen wipers
▪ Engine oil and water
▪ All dashboard display lights
▪ Emergency equipment
▪ Wheel spanner and jack
Use of Mobile Phones in Vehicles
ReplyDelete1. Hand held mobile phones must not be used when driving.
2. Mobile phones may only be switched on whilst driving if attached to a “hands-free” kit. If a “hands-free” kit is not fitted the mobile phone must be switched off or have the calls diverted to a suitable alternative phone. A “hands-free” kit is permanent voice activated equipment installed in the vehicle. It is not an earpiece connected to the phone.
3. Drivers must not make outgoing calls whilst their vehicle is in motion (even if a “hands-free” kit is fitted). If outgoing calls need to be made the vehicle should be stopped and correctly parked in a safe area.
4. Incoming calls should only be answered if it is safe to do so and if they can be accepted “hands-free”. Any conversation must be kept as short as possible. Ideally, the caller should be told they will be called back at a later time e.g. when the vehicle is stationary.
5. The use of mobile phones, including those with “hands-free” kit, in moving vehicles must be kept to an absolute minimum such that the driver’s attention to the road is not compromised.