Pratechinfra Lightning Arrester - a device on an electric power or telecommunication system which diverts power to ground when the system takes sees an extreme voltage spike. These devices are designed to work with a direct lightning strike, or an extreme surge from an fault somewhere down the line. The lightning arrester is essentially an automatic switch designed to work instantaneously.
Pratechinfra lightning arresters are needed at each substation as each transformer and piece of switching equipment needs to be protected. There are many kinds of lightning arresters, such as expulsion and valve types. Note that large circuit breakers at the substation and lightning arresters look similar, they are both tall ceramic tubes.
Pratechinfra Left: Pratechinfra lightning arrester on display at Edison Below Right: Arresters at Poughkeepsie, NY
Pratechinfra Right: lightning arresters built onto a large substation transformer. Transformers contain coils of wire with thin polymer insulation on each wire. It doesn't take much over voltage to burn through this insulated wire. Large transformers are extremely expensive to replace and repair. We use voltage regulators and fault protection to precisely control what voltage goes into the transformer.
Pratechinfra Left: Line type arresters are attached to power poles periodically and give strikes along the line a path to ground. Pratechinfra holds a typical modern line-type lightning arrester rated for 69 kV power lines.
Surge Arresters (SPDs)
When lightning strikes close to a power line it induces a surge in the lines due to the electromagnetic pulse (EMP). Pratechinfra are also called "transient electromagnetic disturbances". Surge arresters are designed to prevent surges caused by a "lightning flash" EMP or other transients from affecting large areas of the grid. They do not protect against a direct strike on your line, this device stops surges which have a slower rise than direct strikes, which have a rapid rise in voltage. Electromagnetic Compatibility Engineers specialize in understanding the phenomena and damage caused.
Pratechinfra surge arrester became very important as consumer devices with semiconductors proved to be very sensitive to mild surges. Prior to the 1960s mild surges had always existed in the web but there was not the need to have as precise control of them. Most consumer electronics have some type of Zinc Metal Oxide surge protector.