All automation and networking components for power utilities now need to be compliant with IEC 61850. But David Moss of GarrettCom Europe argues that not all IEC 61850 compliant products are created equal, and that there’s more to the standard than meets the eye.
David Moss, GarrettCom Europe, UK
When, in the 1990s, deregulation and massive expansion became defining characteristics of the power generation industry, it quickly became apparent that automation was going to hold the key to increased productivity and increased cost efficiencies. But in the early 90s, there was virtual anarchy in the automation industry, with a myriad of different vendors throwing their weight behind an equally large number of different, and often proprietary, communication standards.
With hindsight, we can all see that this worked to no-one’s benefit except that of the vendors themselves, but at the time most industries simply paid their money and made their choice. The power generation industry, however, was perhaps a little more forward thinking. It recognised the cost and complexity problems associated with building automation systems around intelligent electronics devices (IEDs) from many different vendors, and set about drawing up standards which would allow it to reap the benefits of automation free from the constraints of individual vendors.
The various standards have evolved over time, but the most recent to emerge is IEC 61850, covering communications networks and systems in substations. Defining a common communications architecture for substation automation, this comprehensive standard was conceived to enforce interoperability between a variety of IEDs. The wider goal was to facilitate the implementation of systems which took advantage of the latest network products to make more control information available, and to make it easy to transfer that information, seamlessly and reliably, to exactly where it was needed.
Over the last few years there has been a dramatic increase in electric utility automation, and in substation automation particularly, and the importance of IEC 61850 has grown correspondingly. The standard defines industrial Ethernet as the networking backbone for the automation of substations, because of its high reliability and feature rich specifications. These include built-in fibre for high EMI noise immunity, 48 and 110 volt DC power operation, and extended temperature operating capabilities. These specifications allow Ethernet LANs to be designed into substations with control and instrumentation equipment to maintain high availability of electric power to the public.
Enel’s project to upgrade 15 key substations requires robust Ethernet switches which are IEC 61850 compliant and offer high reliability
However, the standard goes a lot further than simply defining the communications standard. It also enforces stringent environmental performance, taking into account all the phenomena likely to be encountered by IEDs and network devices, whether outdoors, in sheltered locations, or indoors. On paper, it is reasonably straightforward to see what levels of conformance different products need to achieve in order to be used in different environments. But the number of different levels is a problem in itself: it is all too easy for a manufacturer to simply stamp a product as IEC 61850 compliant, and be done with it. Buyers therefore need to be aware that not all IEC 61850 products are necessarily equal.
IEC 61850 defines requirements for a range of weather protected and non-weather protected environments. Weather protected locations are split in to class A (air-conditioned locations), class B (heated and/or cooled enclosed locations) and class C (sheltered locations). Non-weather protected locations are classified as class D. However, within all these classes are subdivisions, each specifying their own environmental parameters covering temperature, humidity, air pressure and solar radiation, and specifying whether products should be protected against the likes of rain, ice and frost.
To these climatic variations, IEC 61850 adds requirements to provide protection against electric fields, magnetic fields, electrostatic discharge, conducted high frequency electrical transients, high energy power surges, and ground potential rise during ground faults. The standard also defines requirements for protection against vibration and seismic activity, specifying that equipment should conform to national and international standards according to its location and service. The standard also defines protection against pollution (in the form of dust, metallic particles, condensation and solar radiation), recognising that solid particulates such as dust affect the thermal behaviour of the communications equipment, and that corrosive elements such as salt may affect the connectivity of the equipment.
When Red Eléctrica De Espana looked to deploy a new IP network in more than 300 of its existing substations, it turned to GarrettCom Europe for high reliability, IEC 61850 compliant Ethernet switches
The specific environmental aspects of IEC 61850 are prescribed within IEC 61850-3, which refers to IEC 870-2-2 “Telecontrol equipment and systems – part 2: Operating conditions – section 2: Environmental conditions (climatic, mechanical and other non-electrical influences)”. To be compliant with IEC 61850, IEDs and network products must meet or exceed the specifications.
Environmental conditions are also covered by IEEE 1613, a standard which defines the environmental conditions present in electric power substations and establishes a common reproducible basis for designing and evaluating communications networking devices to be installed in these substations. There is broad correlation between the two standards in this area, but also some interesting and subtle differences. For example, IEEE 1613 specifically precludes the use of fans in the likes of network switches, recognising perhaps that fans can be a cause of EMI within systems. IEC 61850, on the other hand, states that equipment should be capable of meeting the environmental parameters without fans, but doesn’t actually say that they must not be present, with the implication being that it is perfectly permissible to have the fans running in everyday use. It is subtle variations such as these that users need to be aware in specifying equipment.
A key focus of the IEC 61850 standard is on component reliability, such that the substation automation system shall continue to be able to be operable, according to the ‘graceful degradation’ principle, if any communications component fails. There should be no single point of failure that will cause the substation to be inoperable. Adequate local monitoring and control shall be maintained. A failure of any component should not result in an undetected loss of functions nor multiple and cascading failures.
This of course has implications for how systems engineers choose to implement their automation strategy, but for product manufacturers it means that they should clearly state the MTTF of equipment provided, including a reference to a standard method of calculation. Further, rather than simply stamping their products with blanket IEC 61580 compliance, responsible manufacturers should be clearly stating the classification and severity level of environmental climatic conditions that the product is built to survive. The ability to meet general industry environmental conditions is not enough. Products destined for connection to a substation LAN have to be specifically hardened for the substation environment. And that includes the LAN products themselves, such as GarrettCom’s range of Ethernet switches, which will be exposed to exactly the same environment.
GarrettCom’s credentials in the power utility market have been proven over many years. For example, after a major electricity blackout across Italy in 2003, the Italian National Agency for Country Power Management (GRTN) suggested using more sophisticated and automatic systems to manage high voltage electric charges. One of the results was the upgrade of 15 substations, with industrial instrumentation networked over Ethernet using hardened Ethernet switches from GarrettCom.
Further, in Spain, Red Eléctrica De Espana, the utility responsible for the smooth running of the Spanish electricity system, recently looked to deploy a new IP network in more than 300 of its existing substations. It had the goal of implementing connectivity for a range of services and remote control functions. With the communications backbone built on Ethernet, Red Eléctrica turned to GarrettCom Europe for high reliability, IEC 61850 compliant Ethernet switches.
Typical of products specifically designed for this most arduous of environments its GarrettCom’s 32-port, free-convection-cooled 6K32TRC – a major advance in the thermal design of rack-mount Ethernet switches. Specially designed for applications where rack space is at a premium, or for environments where the presence of dust and dirt preclude the use of conventional fan cooling, the 6K32TRC uses innovative casework design and patent pending thermal management techniques to deliver high reliability and extended operating temperatures. This innovative product meets the needs both of IEC 61850 EMC and Operating Conditions Class C for Power Substations, and of IEEE1613.
Rigorous testing of the 6K family fulfills the criteria deemed necessary by the power utilities industry to support mission-critical applications that demand high reliability, electromagnetic radiation immunity, and sustained operation under temperature stress among other tough conditions.
GarrettCom Europe has recently added key products from the Dymec range to its own portfolio. The Dymec ranges of serial IEDs and wide area networking products are cost-effective, hardened, multi-protocol devices purpose-designed for substation operations. They complement GarrettCom’s ranges of managed and unmanaged Ethernet switches, and will allow GarrettCom to offer the unique proposition of providing customers with a fully integrated substation network.
The enhanced product portfolio will make it possible for GarrettCom to support the complete communications requirements of a power substation, including serial or Ethernet IED connectivity at the sensor and relay levels, high-speed connectivity for surveillance devices, and the WAN router that forwards data and control information for centralised processing.
The goal of automation within power generation utilities is clear: to implement systems which are smart at the top and smart at the bottom, self-regulated by millions of communicating devices, and with a seamless flow of information so that critical control decisions can be made correctly, consistently. Thanks to standards such as IEC 61850, power generation utilities are becoming safer, more productive, and more efficient than ever before.