Wildfires continue to devastate portions of the western United States, Australia and other regions across the world. These disasters can be attributed to a variety of factors. Utility companies, in turn, are working to minimize the fire risk posed by overhead lines.
MOV, or metal-oxide varistor, surge arresters are widely applied to protect critical utility equipment and improve grid reliability. Surge arresters come in various designs to protect distribution, transmission and substation assets. The characteristics of the surge arrester are customized to meet the varying requirements of each application. IEEE and IEC standards govern the minimum requirements for all surge arresters, however other characteristics must be considered to meet Hubbell’s demanding quality standards.
There are numerous traits that ensure the quality and longevity of MOV surge arresters. Five key characteristics tend to overshadow others. These include:
A commonly overlooked consideration in arrester applications is the impact of lead length. The inductance of lead wires can produce an inductive voltage drop which in turn will lower system protection. This voltage drop only occurs if the lead carries surge current and is in parallel with the equipment being protected. This resultant voltage is added to the discharge voltage of the arrester during a surge event, thereby reducing the protective margin of the system. The lead wire’s inductance is not strongly influenced by conductor diameter, but rather of overall lead length. Therefore, care must be taken to keep the lead length to a minimum in both distribution and substation applications.
With the recent and upcoming revisions of IEEE C62.11 and IEC 60099-4 surge arrester standards, writing a technical specification for arresters can be challenging for both new and experienced engineers. Most arrester manufacturers have a dedicated team of engineers who are familiar with the evolving standards and can support the revision and/or creation of arrester specifications.
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.
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.
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.