Within the framework of their constraining environment and their precise specifications, many electricity network operators ask for the installation of resistors.
There are 3 types of resistors, useful to the electrical distribution sector:
Earthing resistors – MALT: the safety of installations and people
The Earthing resistance ensures repetitive and permanent protection of substations and their components. This avoids costly repairs or replacements.
In fact, most electrical distribution networks have a neutral connected to the earth in which, in the event of a fault, a very high current would occur. In order to avoid the destruction and disturbances that it could cause, an earth resistance is inserted, between neutral and earth, to limit this current and give the protection devices time to act automatically.
Load resistors – Load bank : test and maintain electrical power
To ensure the safety and performance of electrical installations, it is a priority to regularly test existing energy production systems, in order to maintain them and verify their correct operation: generators, turbines, batteries, inverters, etc.
In the load banks, intended for generating sets, the resistors come into service when the set is operating at low power and prevent the diesel engines from clogging.
The use of resistors as load banks is also customary for the maintenance of accumulator batteries, in electrical laboratories and in telecommunications.
Filtering resistors: ensuring network interconnections – HVDC
The filter resistors are integrated in harmonics filters to ensure the interconnections of networks – HVDC and to “clean up” or purify harmonics disturbing the signal – SVC.
The interconnections of direct current networks, rolling mill trains, and in general, all complex thyristor electrical systems disturb the networks by generations of harmonics. These are eliminated by means of filters comprising high or medium voltage resistors.