UPS systems

One Uninterruptible power supply system (UPS for short) serves the Emergency power supply connected loads in the event of a power failure.

UPS systems are essentially divided into three categories:

• Offline / standby UPS systems of classification 3 according to IEC 62040-3: Provide protection against power failure, voltage dips and overvoltage. This type of UPS system offers the least protection, but at the same time is usually the most cost-effective variant. It is referred to as an offline or standby system, as the system is only switched on when the power is switched off. Power failure the supply of the connected loads. The switching time often results in Voltage dips from up to 10 ms. IT consumers, such as computers, can often compensate for this delay so that no power failure is noticeable at the consumer. These types of systems are therefore almost exclusively for computers or small IT devices that are not mission-critical consumers.

• Line-interactive UPS systems of classification 2 according to IEC 62040-3: Offer additional Protection against short circuits in the public grid and line noise. The Line interactive system is considered Intermediate stage between the Offline and online technology. In contrast to offline UPS systems, systems of this classification also smooth the output voltage so that they also protect the connected loads against voltage peaks and line noise. These types of system are also suitable for protecting computers and, in some cases, server systems that do not require mission-critical represent consumers.

• Online UPS systems of classification 1 according to IEC 62040-3: Offer additional Protection against high voltage peaks, Frequency deviations, Switching tips and Harmonics. UPS systems of the online classification provide optimum protection for your consumers and can be used for business-critical applications. Due to the Double conversion technology arises in the event of a power failure No voltage interruption and the loads are permanently supplied. In addition, systems in this category also protect against various types of voltage faults. As the rectifier and inverter of the UPS system are permanently in operation, a pure sine wave is generated so that an optimum voltage supply is permanently provided for your consumers.

The required UPS power is directly depending on the connected consumers and their Load profile.
In order to correctly dimension the UPS system, the following information is required for the connected loads:

• Performance

• Cosphi

• Inrush current (overload behaviour)

Based on a corresponding load table, the maximum load current and the maximum peak inrush current can be calculated, which serves as the basis for UPS dimensioning.
For all UPS systems, we recommend a Maximum utilisation of approx. 60%to allow for growth and performance reserves.

The Bridging time is direct dependent from the connected loadand the installed battery system. The battery system for the UPS systems can fail differently from 1 kVA, therefore this can be not answered across the board become.

Depending on the connected load and the desired bridging time, battery system different fail. Ideally, the following are sufficient Internal batteries which are installed in the housing of the UPS system. In this case, the space requirement is minimal. With increasing requirements with regard to bridging time and load is, however, often necessary on External batteries which must be installed on a separate rack or in a separate battery cabinet.

The The majority of UPS systems can be equipped with additional network cards or fault messages, so that monitoring can be carried out via SNMP or a connection to the BMS can take place.
However, these monitoring devices are often not installed as standard in the UPS system.

This is also depending on the load to be suppliedand the desired / required bridging time.
Depending on the load to be supplied, standardised requirements may also play a role. In principle, however, every UPS system should be freely accessible and there must be sufficient wall clearance for ventilation. This also depends on the power of the UPS system.

Battery system in particular is subject to standardised requirements due to their escaping gases when heavily loaded.

In the case of battery systems, a distinction is generally made between 5, 10 and 12 year batteries differentiated. However, these are Service life expectations under optimum conditions.

Experience shows that often only 70-80% of this service life expectancy can be achieved.

For UPS systems, the Regular maintenance are decisive for the service life maintenance of the system. With regular maintenance and regular replacement of the necessary wearing parts, UPS systems can have a service life of >15 years reach.

Operator responsibility requires the operator of emergency power systems in accordance with DGUV V3 to carry out regular maintenance on electrical systems. One Proper maintenance should be seen as an investment in the future. No operator of an emergency power system wants a system that does not take over in the event of a power failure.

Maintenance work is therefore advisable to ensure the reliability and availability of your consumers even in the event of a power failure.

We recommend a maintenance interval of one yearThis is also required in the VDE 0105 for electrical systems and electrical equipment.

When using UPS systems for protecting the connected loads result Several advantages for the user or operator.

The first and most important advantage is the Securing the power supply of, for example, server landscapes, sensitive measurement electronics and all types of IT as well as, for example, cash register systems. In the event of a power failure, not only is the loss of data, measurement results or the failure of complex systems prevented, it is even possible to continue working in the event of a power failure without interrupting the supply from the UPS system. The second advantage can also be, for example, the "electrical imbalance" of the house connection and of the building's main distribution board by the UPS system again in a symmetrical utilisation of the three outer conductors (L1,L2,L3) to bring.