Frequency variation in the power system exists due to the mismatch between the supply of power and demand for the power. Voltage variations exist in the power grid is due to the mismatch in the reactive power between demand (MVAR) and available. In spite of all these variations, there is a certain limit for the … Read more
In this article, we will learn about causes of low power factor and methods to avoid low Power Factor. Causes of Low Power Factor Some of the reasons for low power factor are 1. Induction motors and Transformers Where ever the magnetising current is to be produced by the ac power such as in the … Read more
Constant Voltage Transmission Voltage in a long distance transmission line drops from sending end to receiving end due to the presence of line losses in the system ( except on no-load conditions). Voltage regulation and power handling capability are two important features of the transmission line for delivering the power. The voltage of the transmission … Read more
For transmission of more power for long distances to load centers, Extra High Voltage (EHV) transmission is employed. Implementing EHV has an advantage of the reduction in the copper losses and improves efficiency. However, transmission of voltage beyond 300kV will pose some problems such as Corona effect which causes significant power loss and interference with … Read more
Gas Insulated Substations (GIS) differ from Air Insulated Substations (substations we usually see) such that all the substation equipment such as busbars, circuit breakers, current transformer, potential transformers and other substation equipment are placed inside SF6 modules filled with SF6 gas. The SF6 gas which has high dielectric property acts as an insulating medium to … Read more
Stones/Gravel is used in Electrical Switchyard because of following reasons 1. During Short circuit current Step and Touch potential increases. (a) Step potential: It is the potential developed between the two feet on the ground of a man or animal when a short circuit occurs. This results in a flow of current in the body … Read more
Mobile Substations are emergency power supply substations employed temporarily to provide power supply in the areas affected by the natural disasters such as storms, cyclones and during wars. These substations will have a maximum rating of about 220kV. Mobile Substation typically contains Trailer for the unit, Distribution Transformer, Cooling system for Transformers, Switchgear equipment (relays, … Read more
Have you ever seen a ring around the Surge Arrester or other EHV equipment? What is the purpose of the Ring around the Extra High Voltage (EHV) equipment? What is the use of big rings at EHV testing centers? This Metal Ring what we see in the substations and other transmission line network is “Corona … Read more
Air Insulated Substation (AIS) or Outdoor Substations have all switchgear equipment, busbars and other switchyard equipment installed outside open to atmosphere. In earlier days for any voltage ratings, AIS or outdoor substation is employed. Indoor Substation type is only employed in places where high pollution or the saline environment exists. Indoor substations are two types … Read more
Sulfur hexafluoride gas (SF6) properties are given below SF6 gas is Heavy, chemically inert, non-toxic SF6 gas has no poisonous effect on the human body but decomposition products are poisonous SF6 gas is Colourless and odourless It is gaseous at normal room temperature and pressure Density is about 6.6g/l at 20°C (5 times denser than air) … Read more