A protective device called surge arrester limits the voltage on equipment by charging or bypassing the surge current. It can prevent continued flow to follow the current to ground and repeat these functions specified per ANSI (American National Standards Institute). The arrester doesn’t stop lightning or absorb lightning. It can work on the following functions:
- Diverts the lightning
- Limits the voltage
- Protects the equipment installed
The surge arresters have several applications anywhere protecting a home to a utility substation. They are installed on the circuit breakers in the following:
- Inside a residential home
- Inside pad-mounted transformers
- On pole-mounted transformers
- On pole-mounted riser poles
- Substations
Why use surge arresters?
The distribution power line sees various voltage surges. The lighting is the main source of the voltage surges. There are around 100 lightning strikes on the Earth’s surface every second. Lightning is an unpredictable and random event. The other sources of voltage surges include:
- switching surges
- temporary overvoltages
Switching surges are the overvoltages produced by shifts in operating conditions in the system and the primary voltage surge for station-class arresters. Switching surges is to trap energy and the next release of energy.
The function of surge arresters
A MOV (Metal Oxide Varistor) surge arrester contained a series of blocks. The MOV blocks worked like a voltage-controlled switch. It is acting as an insulator within the line voltage. When the voltage arrester experiences increases above the arrester’s reference voltage, the MOV blocks go to conduction. Since MOV blocks are highly non-linear, if the voltage drops below the reference voltage, then the conduction will end.
Why do arresters work?
The surge arresters should withstand continuous power-frequency voltage that intends to operate. It should discharge any quick energy from the system in the form of a current while keeping the voltage across the equipment from becoming extreme. It should operate in the same environment as protected equipment. The TOV (Temporary Overvoltage) can show the acceptable duration and overvoltage an arrester withstands without damage.
The arresters operate for various reasons:
- Undersized arrester
- TOV condition stayed too long
- Gap degradation in the silicon carbide arresters
- Lightning surges experienced greater than duty rating
- Wildlife
- Deterioration of an oil-based polymer housing for leaking of silicone oil additive
- Disk aging
Types of surge arresters
When using surge arresters, you must know the different types of surge arresters, such as:
- Secondary arresters
- Distribution arresters
- Intermediate arresters
- Station class arresters
If the users have a coaxial cable line attached to costly equipment. They are considering purchasing a surge protector. Surge arresters protect the equipment against surges caused by the following:
lightning strikes
electrical storms
other sources of voltage spikes
Porcelain arresters will break apart after experiencing the end-of-life situation. The polymer arresters experience a blowout on the side of the disconnector, which separates the arrester from the ground.
