Electric utility operating system reliability is an important factor of utility performance. As a common practice, distribution arresters are assembled with a ground lead disconnector (GLD) designed to respond to arrester fault current during a short by detonation of a cartridge inside of the disconnector housing.
There are three distribution arrester types commonly used to protect overhead distribution equipment from the damaging effects of overvoltage. IEEE C62.11 defines Normal Duty (ND) and Heavy Duty (HD) classes by their ability to withstand certain current impulse levels. The third, Heavy Duty Riser is a type, or variation, of the HD classification and utilizes a larger diameter Metal Oxide Varistor (MOV) disc.
When comparing different arrester designs, it is important to understand how the arrester was built to correctly evaluate the amount of protection it will provide. The IEEE C62.11 standard covers two types of Metal Oxide Varistor (MOV) distribution arresters that are available today, internally gapped and gapless. These arresters might look identical from the outside, but the different internal module design affects how the arrester protects voltage sensitive equipment.
All Hubbell Power Systems surge arresters are factory tested according to IEEE C62.11 and IEC 60099-4 routine test requirements. Once in use, surge arresters do not require field testing for routine maintenance. If arrester field testing is desired there are several test options with varying levels of usefulness and convenience.
Surge arresters can extend the life of system assets by limiting the voltage across expensive substation equipment during a switching surge event. Station class arresters must be carefully selected to provide the best protection.
Consumer demands for reliable electric power have continued to increase over the years with technological advances. The prevalence of high tech devices has required utilities to provide near uninterrupted service.
Distribution lines are likely targets for lightning strikes. Once the lightning touches the line, the surge divides and travels both directions. The lightning surge will then probably cause an insulator to flash over. Why?
Power surges can damage electronic equipment if not adequately protected. Surge arresters protect a variety of equipment, distribution transformers, power transformers, underground cable, and insulators, from overvoltage. The proper arrester selection can prevent equipment damage.
Lightning protection devices date back to the mid 1700’s. Early technology, such as the lightning rod, originally provided protection for homes, before being adapted for use on the telegraph and electric grids.
The modern term “arrester” was first used in the mid 1800’s for simple gap devices that protected telegraph lines. These products consisted of a simple gap and could be operated remotely by the telegraph worker.