Role of fuses and their parameters

In electricity the fuse is used to protect the appliance during over current. The fuse is generally a low resistance device which is used as sacrificial device. Often it is a metal wire or some strip which melts when current overflows.  The use of fuse interrupts the power flow thus preventing the all electrical appliances connected with the flow of current. During the wiring of house or home, maximum fuse current ratings are marked to know the maximum current that can flow through them without disturbing the current flow. The blowing of a fuse prevents the damage to property and appliances.

The current operating characteristics are selected to provide the protection without any needless power interruption. Slow fuse are used to get the harmless short term currents flow over their ratings but prevents the large over flow. The self resetting fuses automatically come back to the original position after the overload current flow is cleared. These fuses are used in those circuits, where it is no possible for a human being to replace or reset the fuse. Fuses are made with varied range of voltages and current ratings for various electrical circuits and requirements.

Each fuse has a current rating denoting the maximum current that can flow through it without interrupting the flow of current to circuits. The speed at which a fuse blows depend the current flowing Chemical Earthing Material Manufacturers  through it and material of the fuse. The fuse which blows at the slight increase in current is used in household circuits. Most of the fuses in homes are of this nature. the time delay fuse are the fuse , which allow the current above their current rating to flow through them for certain period of time without blowing . These types of fuses are used in motors, where large current is needed before coming to normal speed.

Breaking capacity is the maximum current that is safety cut by the fuse. Often this is higher than the short circuit current. Small fuses have breaking capacity only 10 times their current rating. Some fuses filled with sand or similar material has high interrupting capacity.

Rated voltage of the fuse must be greater than or equal to the open circuit voltage. When the fuses are used in series, there is no increase in the rated voltage .The voltage of fuse also remains same, without any increase in the voltage. The I2t value or rating is the amount of energy that is let through by fuse when it clears the electrical fault. It is normally in short circuit conditions that this term is used.

Fuses area made in Chemical Earthing Material Manufacturers various sizes and shapes for wide use in home and outside the households. Generally, the fuses are made from ceramic, plastic, glass and fiberglass .It can also come in molded mica laminates or compressed molded fire.  Fuses are also made with different enclosures to stop interchange of different ratings of fuses. 

Types of insulators used in high power transmissions

In the context of high power transmissions, the insulators are the support structures for wires and devices. The use of knobs and tube house wiring provides the flexible insulation. The HV power transmission use air as insulation or wires are buried in the ground for insulation.   Besides, these methods, there is no other economic way to insulate the HV lines. In transmission, the insulators are used to separate the wire from any structural support. The other reasons of using insulation is to stop the lighting from connecting the wires ,  and stop sparks or ground shots by not allowing the buildup of water , oil or dirt on the insulator . To prevent this kind of build up on insulators, they are designed in ridged form.

Wood and glass insulators were used initially as the insulators. Dry wood may be good insulator but it is not the perfect one. Glasses were used to insulatre telegram lines and telephone lines, as the electricity was used only for telephone and telegraph lines. However, these were only for low voltage currents.

Ceramics are used to Electrical BPL Kits Manufacturer  insulate the high power transmission lines and temperature. Glass insulators were not able to withstand high power and temperature. They would crack at the high temperatures. Initially the simple porcelain products were used as insulators. But later, for higher voltages, the new designs were made in existing porcelain products to enhance their performance with special coating.

Besides, these insulators, the many other common insulators used according to the requirements of the transmission of power and wires. The plastic has replaced rubber as insulation material for wires.  PVC, nylon and cresyl phthalate are the type of plastic that are used now in most type of wires.

Paper and cardboard are used today in some situations as they are cheap and can be used perfectly with high heat and high voltages. Mica is another good insulator and conductor .mica can be easily shaped and stamped for electrical components. This product is also used in many common capacitors.

Teflon is durable, slipper and have resistant to corrosion. This material is used in cables jackets. Teflon can come in many forms like FEP and ETFE.

PFA, Perfluoroalkoxy is considered better than PTFE in flexibility. It has resistant to chemical attack and is transparent.  The negative point of this material is that it cannot be folded unlimited number of times. The PFA is used near the sea shores, because it has resistant to salt spray. The dielectric strength of this material is 4 times higher than PTFE

Some non conductivity gases GI Strip Manufacturer in Delhi used to stop the formation of arc between two conductors in compact encapsulated metal container. Gas is also used in switch gears to disconnect two voltages safely. Some gas insulated transformers are also used.

Petroleum product is also used as an electrical insulator and heat conductor. The insulating oil can take heat away from transformer coil. Insulating oil is also used by some capacitors.

Purpose and method of earthling

The main purpose of the earthling is to save the installations and also the man working on it. If all the metallic parts of the electrical system are grounded then no dangerous voltage is present in the system even if insulation falls. The person is saved by giving other way to the flow of fault current by blowing the fuse. The earthling also saves building, equipment, machinery and appliances from fault conditions. The other aims of making earthling are to prevent the conducting part from reaching dangerous point. It also gives safe way to the short circuit currents. The earthling keeps the voltage level in a system at known level; this prevents the excess current in the appliances.

During lighting, unintentional contact or surges the high voltage lines can give dangerously voltage to the electrical system, the earthling proves safe path to this current to save the system from damage.

There are various methods of earthling. In the plate earthling method, plates of cast iron or galvanized steel or copper are used. These plates are buried at the depth of up to 8 feet in the vertical position. The GI strip of size approximately 50mmx 6mm is brought to the ground level. This GI strip is bolted with the plate. The earth pit is filled with charcoal and salt in alternate layers up to 4 feet from bottom of the pit.      

In pipe type earthling generally the GI pipe is used. This pipe is 10 feet long with 75 mm diameter with 6 holes for inserting earth wires. The pipe is put in the ground by auger method. The earth pits are filled either with salt and charcoal or with earth reactivation compound.

The resistance of the earth Drop out Fuse Set Manufacturers to the passage of current depends on the condition of the soil and it varies from soil to soil. The physical composition of the soil, the level of moisture in it, amount of dissolved salts, size of grains, and season variations of the earth, all affect the resistivity of the soil. The dry soil is very poor conductor of the current.

Moisture also has a say in the soil resistivity. The earth itself is not good conductor of current but the presence Chemical Earthing Material Manufacturers of water or salinity in it can cause current to flow through it. Therefore the water is added in and around the earth pit to keep moisture in it. During dry conditions, the level of moisture determines the soil resistivity. The moisture in climate also influences the soil resistivity. In rainy season the soil resistivity will be low. While in dry season, the resistivity is high. Location of the earth pit also determines the soil resistivity. The place where water runs off from slope and hilly areas, the pit will remain dry.  Earth pits in such places are given water at frequent intervals especially in dry weather.

Issues faced by the power sector in India

Most of the power produce comes from the thermal power plants and the coal is the main fuel used in these plants. The quality of the coal from Indian is of low that is why the coal has to be imported from foreign countries.   The use of coal also adds to the air pollution and environmental issues.

Efforts are on to reduce the dependence on coal and increase the power generation from other sources such as wind energy, nuclear and solar energy. But still the major share of power comes from thermal power plants .The coal handling and ash handling is another issue that is faced by the thermal power plants.

The large electrical items that are used in the power plants are imported from other countries. The local manufacturing facilities are not able to meet the demand of the plants. The shortage is not only in the boilers, generators or turbines but also in small items like switches as well.

Land acquisition is a politically sensitive issue in the power plant construction. Since power plants are constructed in the far flung areas and often include agriculture lands.  The farmers lobby works against the land acquisition and then get the support of opposition political parties. The government cannot avoid the opinion of these people as often they decide the electoral success of political parties. This delays the implementation of power project policies.  Even if the land is taken for power projects, then getting environmental clearance take months and sometimes the issue can go for years. The new land acquisition bill continues to face tough opposition from almost all political parties. No political party wants to damage its election prospects by going with the land acquisition bill. When government is not able to get the land for power plants, the private companies also do not want to take the chance to come in investment proposals in power sector.

High distribution and transmission losses are one of the major problems affecting Indian power industry. These huge losses can reduce the gap between demand and supply. Saving of 1% of these losses can add 800 MW power generations.

Obsolete plants and Electrical BPL Kits Manufacturer transmissions lines increase the losses and cannot take the load during peak hours. This is one of the reasons for the low growth electricity generation and transmission. In recent years the demand for electricity has increased manifolds in the country. The government is trying to have more nuclear plants for power generation. The only concern with the nuclear power plants is that the spent fuel needs to be handled cautiously.

The hydro electric projects GI Strip Manufacturer in Delhi cannot be constructed at every river because of erratic   behavior of monsoon and dry spell which country faces from time to time.  Also interstate disputes on river water flow and sharing of river water practically do not support the construction of dams across river connecting more than one state.