Table of Contents
Why are stones layed in switchyard?
Using stones in the switchyard provides protection against the entry of wildlife animals and snakes, lizards, rats etc in the substation area. Stone and gravels increase the resistance of soil which leads to reduce the limit of touch and step potential.
Why do we put gravel in substation?
Touch Potential – It is the potential that is developed between the gorund and the body during fault condition. That is why substations uses gravel/stones to reduce the step potential and touch potential when operators work on switchyard.
What is the purpose of a switchyard?
A switchyard or substation is an assembly of apparatus which transforms the characteristics of electrical energy from one place to another and controls the flow of power. Switchyard controls the exchange of electrical energy.
Which is used in substation?
The Substations are mainly used to convert AC (alternating current) to DC (direct current). Some types of substations are tiny in size with an inbuilt transformer as well as related switches. Other types of substations are very huge with different types of transformers, equipment, circuit breakers, and switches.
Which busbar arrangement is more reliable and flexible?
The breaker and half configuration is very flexible, highly reliable, and more economical in comparison to the Double Bus Double Breaker scheme.
What is GPR in earthing?
Ground Potential Rise (GPR) or Earth Potential Rise is a phenomenon that occurs when large amounts of electricity enter the earth. When currents of large magnitude enter the earth from a grounding system, not only will the grounding system rise in electrical potential, but so will the surrounding soil as well.
What is a switchyard in energy?
Electrical substations are the interface between parts of the distribution grid and transmission systems. These fenced off areas (see Figures 1 and 2) step down the voltage in the transmission lines to one that is suitable for the distribution grid.
Which is the cheapest form of substation?
Ans : Pole mounted substation is the outdoor type cheapest form of substation for voltages not exceeding 33kV in which the equipments are installed overhead on H-pole or 4-pole structure and electric power is almost distributed in localities through such substation.
What is inside the substation?
The compartments of such substations take the form of metal cabinets or enclosures, each of which contains the equipment of one main connection cell. In such cabinets, an oil circuit breaker, a load interrupter switch, and one or more voltage transformers may be mounted.
Which material is used for busbar?
Sometimes spelled bus bar or buss bar, they are often metallic strips of copper, brass, or aluminum that both ground and conduct electricity. Different coating materials provide different conductivity limits and variations in the length of a product’s useful life.
Why are stones / gravel used in Electrical switchyard?
This is defined as touch potential. Gravel/Stones in the substation is provided to reduce the step potential and touch potential when operators work on switchyard. 2. Power Transformers installed in the substations will have oil as cooling and insulating medium.
Why are stones laid in an electrical substation?
That’s why stones or gravel are laid in the substation to reduce the step potential and touch potential in case of maintenance or working on live equipment. The following table shows the resistivity of different materials such as stones and sand etc.
Why is oil used in electrical switchyards?
Power Transformers installed in the substations will have oil as cooling and insulating medium. Oil leakage takes place during operation or when changing the oil in the transformer. This oil spillage which can catch fire is dangerous to the switchyard operation.