The development from the conventional to the digital techniques provokes a great progress into the technological level of the T&D substations and Power plants.
The Digital Substation Concept (DSC) considerably raises the functionality and operational reliability, and reduces the duration and expenses for the power object secondary equipment installation and maintenance.
The Digital Substation is a term applied to electrical substations where operation is managed between distributed intelligent electronic devices (IEDs) interconnected by communication network.
One of the most important features of the DSC is the level of communication redundancy. Two types of DSC redundancy are simultaneously available – at a communication level and at a physical level.
At communication level IEC61850 edition 2 allows two redundancy protocols with zero recovery time to be defined in the IEC standart 62439-3 and to be applied for the Station and the Process bus – Parallel Redundancy protocol (PRP) and High Availability Seamless Redundancy protocol (HSR).
At a physical level, the proposed new approach is to use data flows for the current and voltage sampled values (SV) from different physical sources – separate Merging Units (MU) connected to different CT cores and VTs. This means that each Protection Device (PD) of the definite bay is able to receive IEC61850-9.2LE data for the currents and voltages from more than one physical source. Moreover each IED is equipped internally with Ethernet switch that makes unnecessary the application of the external one.
The mentioned approach of the DSC provides high level reliability and 100% operability in case of single element failure (device or connection). Moreover in case of “turnkey” project, the overall expenses for the digital substation should be significantly less than the conventional.
The high level of the DSC reliability obtained via the upper mentioned redundancy allows the implementation of combine main and back-up protection functionalities in a single device and installing of only two separate devices – Main and Back-up. Each of the devices can be physically reserved.
A new vision to the Digital Substation Concept allows company ROCON first in the world to offer IED with embedded RedBox providing gateway between PRP and HSR topology.