IEC 61850 is the global standard for protocol in the power utility automation field. Developed by the International Electrotechnical Commission (IEC) – an international standards organization, it was originally implemented in 2004. Initially defined to bring proprietary systems from different vendors to a common set of protocols, it has now become critical to the efficient engineering of substation automation systems. In addition, the standard is today being applied to the domain of distributed energy resources and is considered essential to smart grids. These distributed energy resources include automation of photovoltaic plants, wind power systems, systems combined heat and power systems.
With the introduction of IEC 61850 Edition 2 in 2011, came the advent of the Digital Substation. Even though the concept has evolved since then, the basic principles remain unchanged: replacing bulky current and voltage transformers with small, integrated sensors and substituting signaling copper wires with fiber optic communication buses.
Digital substations remove the last electrical connection between high voltage equipment and protection and control panels, creating a safer work environment, while reducing the expense on physical assets such as building and land. They also help to bring down the cost of engineering, commissioning, operation and maintenance of the substation and the distribution automation systems. Compared with traditional substations, digital substations are quicker to deploy and offer improved data quality and shorter decision time if there is an emergency. With utilities continuing to integrate increasing amounts of intermittent renewable energy sources, digital substations are becoming an indispensable component of most modern-day smart grids.
The defining feature of a digital substation is the implementation of a process bus. A process bus is the communication link between primary equipment in the switchyard and secondary equipment including protection and control equipment in the control room. The IEC 61850 process bus enables the substitution of point-to-point copper connections between switchyard equipment such as instrument transformers and switchgear and protection and control IEDs (Intelligent Electronic Devices) by means of a safe, standardized optical communication bus.
By replacing copper cables between the switchyard and the relay house with fiber optics, up to 80 percent of the used copper cables can be spared. Assuming an average-sized transmission level substation that has seven feeders, this would mean more than 30 tons of material saved resulting in further cost savings related to transportation and the reduction of a substations carbon footprint.
And last but not least, the most important advantage of a digital substation probably is the increased safety; the risk of electrical shocks is significantly reduced for operators and maintenance personnel. Handling of current transformer circuits and signaling voltages poses a threat to people and can damage the equipment. Process bus eliminates the galvanic connection between protection and control panels and the switchyard. It replaces conventional 110/220 V DC signals with fiber optics and hence can save lives.
Since its publication in 2004, the global standard IEC 61850 has been accepted at an unexpectedly fast rate. ABB continues to invest tremendous efforts in implementing this standard at the core of its systems, tools and products. ABB believes that IEC 61850 is the basis for a successful and modern digital grid.