Which of the following devices will receive voltage surge first traveling on the transmission line?
Right Answer is:
Lightning arresters are devices that help prevent damage to apparatus due to high voltages. The arrester provides a low-impedance path to the ground for the current from a lightning strike or transient voltage and then restores to normal operating conditions.
Lightning arresters are connected between line and ground, and the arrester should be located as dose as possible to the terminals of the equipment being protected. For example, surge arresters used to protect the transformer in the substation may not protect the transformer if they are placed more than a meter away. If the transformer has primary fuses (which is most frequently done, the surge arresters can be placed on either side of the fuses; however, the most common practice is to place the surge arresters at the transformer terminals because this location provides the highest degree of protection for the transformer. Surge arrester leads should be as short and straight as possible. The leads must never be coiled or have any sharp bends.
The lightning arrester should have the following characteristics:
- The lightning arrester should not absorb any current during the normal operation, but during overvoltages, it must provide an easy path to earth.
- The impulse spark-over voltage of the arrester must safeguard the insulation of the terminal apparatus.
- The diverter must be capable of carrying the discharge current for a short duration without being damaged.
- The arrester must, after discharge, cease to catty any current, i.e., it must seal in itself.
- After an operation, the arrester must be in a condition to accept and deal with ensuing surges i.e., there must be no failure of the arrester itself.