The concept “Self-Power” defines the supplying mode of electronic protection relays for Medium Voltage.
It means that there is no need for auxiliary voltage to power the relay and that the energy is obtained directly from the line that we are protecting.
This means that maintenance of transformer and distribution substations is heavily reduced. All batteries, chargers and other external power elements are made redundant.
The energy is obtained through current transformers installed in the line we want to protect.
There are two options respecting to the transformers:
Self powered Relays do power themselves from the primary current and the energy is scarce, so an efficient management of this energy is indispensable.
Due to this situation using coils is not viable because they have a very high electrical consumption. The solution is to use a striker.
It’s a bistable device with a simple action. It consists on an electromagnet that is charged when the breaker is closed (To trip, it required low energy, 100 millijoules approximately) The striker shaft is moved by a spring. And activated by a polarized low power electrical signal, supplied by the relay if a fault occurs.
Yes, it is possible to use a Self-powered Relays if the installed opening mechanism is a coil, but it is necessary to install an external device with the relay.
Fanox offers amongst its products catalogue the TCM adapter. This device is connected to the trip contact of the relay and provides the required energy to trip a coil.
TCM is an energy accumulator that can be charged, through its auxiliary supply terminals, before the installation or once the device is installed, if in the installation auxiliary supply is available. The charging time is 10 seconds approximately and once the power supply is lost the TCM has three days of autonomy.
Besides, all models can be powered from an external battery, in order to facilitate the commissioning of the centers (the settings and configuration procedure can be carried out without installing the relay), to manage the incidents that may occur and also to manage the devices in adverse conditions.
Fanox SIA-B Specific CTs is a powerfull solution for overcurrent protection. This relay is the perfect choice if you look for a competitive and complete solution composed by relay + CTs for overcurrent protection while having all functions required for a maximum safety.
Protection functions:
Impeccably suited for protection in distribution systems, with minimal space requirement SIA-B compact relay provide a comprehensive range of functions in a amazingly compact and space-saving housing. Fanox SIA-B Standard CTs is our best solution for last generation switchgears where the available space is critical thanks to its reduced dimensions. This feature combined with the use of standard /1 CTs allows it to fit into almost every actual switchgear.
Protect your installation with the highest precision thanks to oscillographic records plus extra events and fault records, requiring minimum current levels for the relay to start.
Protection functions:
Extensive experience of successfully operating devices in the field worldwide, thanks to these unique advantages, SIA-C SERIES enjoys top recognition among users worldwide