The digital revolution is ongoing and has already taken great steps in the energy segment and it’s bringing immense opportunities and benefits.
To take full advantage of what digitalization can offer, the utility of the future will be a fully digital system. Already today, utilities and businesses can reap the benefits this revolution brings: the digitalization of electrical distribution in the medium-voltage network starts with installing digital switchgear – part of the ABB Ability™ portfolio*.
The impact of digitalization on electrical distribution is destined to improve operations and increase flexibility throughout the power value chain, from generation to customer relationship management. Already today installing digital switchgear contributes greatly to increasing operation efficiency by optimizing switchgear footprint in the substation room and by using the energy efficiently for switchgear operation. For example, in a medium-voltage switchgear at 11 kV consisting of 30 panels, the width can be reduced by approx. 7% and switchgear energy consumption can be reduced by approx. 300MWh during its lifetime (source: www.abb-unigeardigital.com/calculator).
Today governments and regulatory bodies encourage smarter measuring systems and greener standards for generation and consumption and to use resources in a more efficient way. These initiatives create a demand for smarter distribution equipment, which could support its users in all this, and that is where digital switchgear brings its value. Digital switchgear with its outstanding communication capabilities can play an integral part in a very complex system of management and control.
Digital switchgear is answering the industry need for bi-directional power flow, to cope with renewable energy sources in the network and to balance correctly the generation and consumption, while keeping a stable energy supply to its consumers. Renewables are opening up new demands in how to operate the grid, and grid operators needs to react to it by knowing more information about the network itself, e.g. daily demands, maximum nominal currents, weekly consumption graphs, while adapting the network protection schemes.
Changing load flows in the network, is not a problem with digital switchgear, as the equipment allows users to adapt the switchgear to application requirements. This helps to better protect equipment in the network and network itself, while safeguarding the network stability and delivery of electricity to consumers. This was one of the winning arguments for the digital switchgear solution delivered to RICE in the Czech Republic.
The digitalization of medium-voltage switchgear with currently available technologies, means utilization of sensors as metering devices instead of conventional instrument transformers and utilization of digital communication between intelligent protection relays. Sensors are based on Rogowski coil principle for current measurement, while voltage sensors are based on the resistive or capacitive divider principle. Sensors based on alternative principles have been introduced as successors to conventional instrument transformers in order to significantly reduce size, increase safety, and to provide greater rating standardization and a wider functionality range.
Protection relays have also taken a huge step in the development of its functions, which allows us to utilize them in more complex scenarios and protection schemes. Especially the digital communication, based on IEC 61850 standard, is opening up new opportunities in how we optimize and improve overall switchgear design, while we introduce a more reliable system. The reliability of the digital communication is safeguarded by utilizing redundant communication topologies, HSR or PRP, and by having self-supervision functionality in notifying potential disruptions in communication to operator interface. Moreover digital communication help us reduce extra wiring used for signal sharing, and by replacing it with single or double e.g. optic cables, which can handle even more data in a faster way. IEC 61850 does support not only exchange of binary data, via so called GOOSE (Generic Object Oriented Substation Event), but it also supports sharing of analog measurements between the protection system not only within the substation, but in the system wherever needed. This further improves simplification of overall system design and utilization of data at multiple places for protection purposes.
The technologies used in digital switchgear today increase safety for operators and people working around medium-voltage equipment, as operation and monitoring of the switchgear can be done from a safe distance. Sensors working on alternative principles, Rogowski coil and resistive dividers, represent measuring devices with higher safety standards thanks to low level output signals. The connection of sensor and protection relay is plug-and-play, via ruggedized industrial type RJ-45 Ethernet connectors.
These technologies are already in use in digital switchgear solutions, bringing great benefits and improved reliability, and availability in medium-voltage distribution networks. As we continue on this journey to a digitalized world where big data processing, cloud services, and data communication take giant leaps, it will be fascinating to see how we will be able to make the electrical grids of the future even smarter and provide digital opportunities to improve operations throughout the value chain.
*ABB Ability™ is our cross-industry digital capability — extending from device to edge to cloud — with devices, systems, solutions, services and a platform that enable our customers to know more, do more, do better, together.
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