EHV AC stands for Extra High Voltage Alternating current and HVDC stands for High Voltage Direct current. As compared to EHV AC, HVDC has following advantages and disadvantages. Advantages 1. HVDC systems are economical for long distance bulk power transmission by overhead line (reduced tower costs). 2. There is greater power per conductor and simpler line … Read more

Q. Why the thermal efficiency of a steam power plant is quite low? Ans. In a steam power station, more than 50% of the total heat of combustion is lost as heat rejected to the condenser and this loss is unavoidable as heat energy cannot be converted into mechanical energy without a drop in temperature, … Read more

When an alternating potential difference between the two conductors of a transmission line is raised beyond a certain limit, a point is reached when a pale violet glow appears on the conductor surface, together with a hissing noise. This phenomenon is known as Corona. Actually, air particles around the conductor surface get ionised and as … Read more

Frequency and Voltage are two important parameters which decide the healthiness of the electrical grid at a particular instant of time. Frequency fluctuations occur in the electrical grid when there is a mismatch between the amount of power generation and amount of power demand. Both under frequency and over frequency operation is harmful to the … Read more

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