Overvoltages are an increase of voltage in the electrical network which can cause damage to the electric installations and equipment. Protection against overvoltages are aimed to avoid data corruption in the network, fire, damage on installations or equipment, among others.
What is the need for protection against over voltages what are the basic principles of over voltages protection of load equipments?
The fundamental principles of over-voltage protection of load equipment are: 1. Limit the voltage across sensitive insulation. 2.
What is the need of over voltage protection of SCR?
The Thyristor or SCR, Silicon Controlled Rectifier can be used to provide overvoltage protection in a power supply circuit. By detecting the high voltage, the circuit can fire the thyristor to place a short circuit or crowbar across the voltage rail to ensure it does not rise to high in voltage.
What are the causes of over voltages explain the protection against over voltages due to lightning and switching surges?
The main cause of these voltage surges in power system are due to lightning impulses and switching impulses of the system. But over voltage in the power system may also be caused by, insulation failure, arcing ground and resonance etc. … But over voltages occur in the power system due to lightning is very high.
What will happen if overvoltage?
The overvoltage can cause excessive current to flow as well as creating excessive voltage stresses. In both cases, the electrical insulation system inside the motor or equipment can be degraded reducing life or causing damage.
What are the methods for protection against over voltage?
The most commonly used devices for protection against lightning surges are : (i) Earthing screen (ii) Overhead ground wires (iii) Lightning arresters or surge diverters Earthing screen provides protection to power stations and sub-stations against direct strokes whereas overhead ground wires protect the transmission …
What are overvoltage protection devices?
Low-Voltage Power Distribution.
What is the protection provided in SCR against high dI DT?
di/dt protection: The anode current starts flowing through the SCR when it is turned ON by the application of the gate signal. This anode current takes some finite time to spread across the junctions of an SCR.
What are the factors affecting overvoltage?
It has been shown * that cathodic overvoltage is influenced largely by the physical condition of the metal, the degree of hardness, and previous treatment, such as electro-deposition at different current densities.