How is surge arrester rating calculated?

The rating of a lightning arrester is given below, Normal or rated voltage: It is designated by the maximum permissible value of power frequency voltage which it can support across its line and earth terminal while still carrying effectively and without the automatic extinction of the follow-up current.

What is the range of voltage for valve type arrester?

Station Type Valve Lightning Arrester – This type of valve is mainly employed for the protection of the critical power equipment in the circuit of 2.2kV to 400kV and higher. They have the high capacity of energy dissipation.

What is a Class 2 surge arrester?

SPD Class II. Good protection level. OVR type 2 and Type 2+3 are designed to protect electric installations and sensitive equipment against indirect surges with ensuring a low protection level (Up). It is characterized by its capacity to safely discharge current with 8/20 µs wave form.

What are the different types of surge arresters?

Normal duty arresters are used in low lightning applications, heavy duty arresters are used in high lightning applications, riser pole arresters are used where the distribution line goes from overhead to underground and the Evolution arrester can be used for all overhead applications.

What are the voltage ratings of surge arresters?

These arresters carry no current in the normal state. Each arrester model has a single voltage rating. For solidly (effectively) grounded systems, the next higher arrester rating above the system line- to-neutral voltage is used.

What kind of arrester is a valve type?

The valve type arrester is also known as gap surge diverter or silicon carbide surge diverter with a series gap. The valve type arrester consists of a multiple spark gap assembly in series with the resistor of nonlinear element. The each spark gap has two elements.

What is the discharge voltage of a MOV arrester?

This example is for a station class arrester but can be used to understand all discharge voltage tables of all arresters. Metal-oxide varistor (MOV) type arresters have two voltage ratings: maximum continuous operating voltage (MCOV) and rated voltage. The arrester MCOV is shown in group 2 of table 1 and given in kV (1 kV=1000 volts).

What is the discharge value of a lightning arrester?

The maximum voltage developed across the arrester terminal and transmitted to the terminal equipment is known as the discharge value of the arrester. The valve type lightning arrester may be station types, line types, arresters for the protection of the rotating machine distribution type or secondary type.