The most basic structural components of valve type lightning arrester are spark gap (referred to as gap) and nonlinear working resistor plate (referred to as valve plate), which are connected in series and stacked in a sealed porcelain bushing. When a dangerous overvoltage occurs in the power system, the gap is quickly broken down, and the surge current flows into the ground through the valve plate. After the overvoltage on the line is eliminated, the spark gap quickly cuts off the power frequency continuous current (the spark gap will not be broken down by normal power frequency voltage), keeping the line insulated from the ground and restoring normal operation.
According to the different structural performance and usage, there are mainly the following types of valve type lightning arresters:
(1) FS type lightning arrester. This is a common valve type lightning arrester with a relatively simple structure, average protection performance, and low price. It is generally used to protect distribution equipment of 10kV and below. Such as distribution transformers, pole mounted circuit breakers, isolating switches, cable heads, etc.
(2) FZ type lightning arrester. This type of lightning arrester has parallel shunt resistors next to the spark gap, providing good protection performance. Mainly used for the protection of 3-220kV electrical equipment.
(3) FCD type lightning arrester. This is a magnetic blow valve type lightning arrester, which not only has shunt resistors but also shunt capacitors in the spark gap, with ideal protection performance. It is mainly used for the protection of rotating motors.
(4) FCD type lightning arrester. It is also a magnetic blow valve type lightning arrester with better electrical performance, specifically designed for the protection of high-voltage electrical equipment in substations.