EWE AG in Oldenburg, Germany
Avoiding surge-related system failures

EWE AG in Oldenburg, Germany is an important company for power, the environment and telecommunication. EWE supplies over 700 thousand customers with natural gas and also operates two gas storage tanks in Northern Germany in salt domes having 21 caverns of 700,000 m³ each, and 13 billion kWh of power.

Application

EWE covers its yearly natural gas requirement with constant procurement quantities.

During weak load periods, such as in summer, the gas is pumped under pressure into the salt dome and is extracted from there during times of high demand.

In order to ensure the power supply, the systems must always be available. Therefore, surge protection is especially important.

Sensors and actuators, as well as valves and drives installed outdoors

Sensors and actuators, as well as valves and drives, are installed outdoors. Plant control and process visualization, however, are located in the control room.

All information is transmitted to the main computer in Oldenburg via long-distance data transmission.

Protection concept

Uninterruptible power supplies (UPS) protected with VAL-MS surge arresters

The power supply protection concept is mainly designed with two stages.

With FLT-PLUS lightning arresters in main distributions, and VAL-MS surge arresters in sub-distributions and control cabinets.

Based on the required high availability of important system parts, these are supplied with uninterruptible power supplies (UPS), which, in turn, are protected with VAL-MS surge arresters.

Many signal transmissions are designed as Ex ia circuits. These intrinsically safe circuits are protected with TERMITRAB TT-EX(I)-24DC.

The two-stage protective circuits with powerful surge arresters and fast-reacting suppressor diodes are set up in the arresters, which are only 6.2 mm wide.

Due to the low protection level and the high discharge capacity of 10 kA, the electronics are reliably protected, and require little space in the control cabinet.

Secure protection for the electronics with low space requirement in the control cabinet

MT-2FM-RJ12

TERMITRAB TT-2-PE-24DC protect the signal circuits which do not require intrinsic safety. The communication interfaces are protected from surges with MODUTRAB MT-2FM-RJ12.

Thus, a seamless protection concept for outdoor equipment and indoor control systems is realized. This guarantees reliable protection for all system components.

Summary

The comprehensive protection concept from Phoenix Contact effectively avoids surge-related system failures, and the gas supply of EWE AG is ensured for all types of weather.