Intelligence instead of copper
The main challenge in this project was the connection of the medium-voltage switchgear of the paper mill, about a kilometer away, to the protection and control system of the substation.
We decided to use intelligence instead of copper with a process bus system according to IEC 61850. All necessary messages and commands, as well as the current and voltage values of the medium-voltage switchgear, are fed into the bus system via SIPROTEC 5 merging units.
This means that the measured values are available to all devices within the bus system, even the differential protection and voltage regulation for both transformers.
750,000 tons of paper annually
“As part of its Green Hightech strategy, the Progroup paper mill produces 750,000 tons of corrugated base paper of the highest quality every year. The enormous amount of electricity that our production needs every day is supplied by our new substation, which was built on the green field. "
Phillipos Vrizas, Head of Technology Paper
Progroup Paper PM3 GmbH
Saving resources in production and in the secure power supply
Only recovered paper is used and the use of fresh water is reduced, which ensures that resources are conserved in production. Innovative process bus technology is used to conserve resources in the redundant power supply.
Elektrotechnik Oelsnitz/E. GmbH (eto GmbH) developed the solution with process bus technology in coordination with Siemens AG and MITNETZ Strom GmbH. In addition to the construction of the secured network and the required time synchronization with the Precision Time Protocol according to IEEE 1588, which enables accuracies of less than one microsecond, redundancy is the special challenge.
Technical solution
To implement the transformer differential protection and the voltage regulation, the low-voltage side measured values of the current and voltage of the transformer are required. These measured values are digitized by SIPROTEC 5 merging units, fed into the process bus system and can be processed by the protection and control system. The tripping signals of the main and backup protection are sent from two separate SIPROTEC 5 protection devices via two separate networks as GOOSE to both merging units, which then trip the relevant circuit breaker. The use of two transmission paths ensures reliable all-round isolation of a defective transformer even if a component of the protection system fails.
Saving four tonnes of copper
In the end, we saved more than four tons of copper for the control, signal and measurement cables, which means considerable resource savings. I personally believe that this promising technology will play an important role in future plant design.Marek Reschke - CTO eto GmbH
