Electric Power

Substation Communications
for use in Harsh Environments

Utility Grade Networking

Trends in electric utility automation, specifically substation automation, have converged upon a common communications architecture with the goal of having interoperability between a variety of Intelligent Electronic Devices (IEDs) found in the substation. The resulting international standard, known as IEC 61850, began in the late 1980s and was driven by major North American utilities, under the technical auspices of EPRI (Electric Power Research Institute). The network architecture currently being adopted worldwide by utilities and IED vendors alike utilizes a common underlying technology — Ethernet.

Compact Modular Hot-Swappable Layer 3 Switch and Router

Utility Grade Products for the Substation Environment

RuggedCom has the industry's most complete product basket of Networking Devices designed specifically for the substation environment. The above network architecture illustrates the range of products available in the context of an IEC 61850 substation. Other network architectures such as ring or star topologies, or a hybrid topology, are also easily accommodated.

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Why Utility Grade Products for the Substation Environment?

RuggedCom has led the development of networking technology for substation communication with many industry firsts that include:

First to develop Ethernet switch technology that exceeds IEC 61850-3 EMI and environmental requirements. Introduced in early 2002, at the same time as the IEC 61850-3 standard was released, the RuggedSwitch^® family of Substation Hardened Ethernet Switches has become the standard for substation LAN deployment.
First to develop Zero Packet Loss™ (ZPL) Technology. What is Zero-Packet-Loss™ technology? ZPL allows the substation LAN to perform without losing a single packet of data when exposed to EMI stress. What is EMI stress? EMI stress is the term given to describe the EMI phenomena which can occur in substations. Standards such as IEC 61850-3 describe the type tests which simulate these phenomena. Mission critical devices such as protective relaying systems must perform without error during the application of such type tests. Thus it makes sense that the devices which comprise the substation LAN (i.e. the Ethernet switches) perform the same way. RuggedCom developed the RuggedSwitch^® family of fiber optic Ethernet switches to perform without error under EMI stress. This means no data loss, errors or delays when exposed to the destructive type tests described in IEC 61850-3. Zero-Packet-Loss (ZPL) technology provides error-free communications for high EMI environments.

First to qualify as an IEEE 1613 Class 2 Error-Free Device under EMI stress as defined by the prescribed IEEE 1613 suite of destructive type tests. RuggedCom was a key participant in developing this IEEE Standard.

The Need for Utility Grade Networking Products

The proliferation of Ethernet capable IEDs used for substation automation has increased markedly in the past several years. There are currently nine vendors of protective relaying devices alone offering Ethernet communications with their IEDs. Vendors of meters, RTUs and PLCs used for substation automation, also mirror this trend.

A key requirement of most substations IEDs such as protection relays is that they must operate properly (i.e. not ‘misoperate’) under the influence of a variety of EMI phenomena commonly found in the substation. Standards such as IEEE C37.90.x and IEC 60255 define a variety of type tests designed to simulate EMI phenomena such as inductive load switching, lightning strikes, electrostatic discharges from human contact, radio frequency interference due to personnel using portable radio handsets, ground potential rise resulting from high current fault conditions within the substation, and a variety of other EMI phenomena commonly encountered in the substation. This will also be true of the substation LAN equipment (i.e. the Ethernet Switches). Often the Ethernet switches will be installed in the same compartment or even on the same rack as protective relaying IEDs. Therefore, it has become necessary that the Ethernet equipment become “substation grade”, from an EMI immunity perspective, to the same level as protective relaying IEDs.

IEC 61850 addresses the need for substation grade networking devices. It consists of 10 parts providing a comprehensive set of standards for communications networks in substations. Everything from environmental and EMI immunity requirements (IEC 61850-3) to conformance testing (IEC 61850-10).

The IEEE Power Engineering Society also developed a standard to address the proliferation of Ethernet networks in substation automation. Released in August of 2003, the IEEE 1613 IEEE Standard Environmental and Testing Requirements for Communications Networking Devices in Electric Power Substations addresses the environmental and performance requirements in networking equipment in substation environments. The majority of the specification was adopted from the IEEE C37.90.x standards for protective relaying systems.