Uninterruptible Power Supply
Since the name Uninterruptible Power Supply (UPS) has not been translated into our language correctly; quite a few misconceptions and expectations have emerged in Turkey about this system. In English, “Uninterruptible Power Supply”, in German “Unterbrechungsfreie Strom Versorgung”, the first word in both means “uninterrupted”. In English, power is defined as uninterrupted, and in German, current is defined as uninterrupted. In English, “supply”, in German “Versorgung” is used to supply, provide, replace, meet the need. However, in contrast, this word is directly translated into Turkish as “source”, creating a situation where the system is perceived as a “generator” or a “generator”.
Although the presence of batteries in the UPS system that can store enough energy to be used in case of an outage and the provision of uninterrupted power via the inverter when the input energy is cut off seems like a “source” behavior; this feature is not enough for the UPS system to be accepted as a “source” within the scope of the Data Center Physical Infrastructure.
The generator system that will be used as a source in an electrical system must have low internal impedance, be able to provide very high power and short circuit current capacity according to the loads in the electrical circuit it feeds, and have a constant voltage and frequency producing feature that is not affected by the load. In addition, it is essential that this performance is provided continuously and with high work continuity, with minimum interruptions as much as possible.
The main task of the UPS is to provide energy to the critical load at a level higher than the energy quality level in the network. This task description also includes ensuring the uninterrupted continuation of power by using the energy stored in the batteries during short-term network outages.
Although it is known that the UPS has a statically low internal impedance with the new technologies used, it should not be overlooked that it has limited power and limited short circuit current capacity. In the normal operating mode where the electrical network is available, the UPS must protect its inverter by shutting it down in order to prevent it from breaking down in case of excessive power demands. Therefore, almost every UPS system has a bypass line to be used in such cases. In case of an overload that the inverter cannot handle or a short circuit that it cannot solve, the UPS transfers the load to this bypass line and idles the inverter. If the same situation occurs when there is no network and it is in battery mode, the inverter will be silent and the critical load will be left without energy.
If the source is to provide energy continuously and with high work continuity, the continuity of the UPS in battery mode is limited only to the energy accumulated in its batteries. It is also impossible to charge the batteries that are discharged during a network outage in any other way. It takes 10 hours for the UPS to charge the batteries that it discharges in 10 minutes.
The UPS within the scope of the Data Center Infrastructure is only a power conditioner. It is assumed that the battery mode will be very short-term, but it can be used for a limited load as emergency energy in cases where all source support is consumed. (Dynamic UPSs, which are a combination of generator and UPS, are not included in this scope.)