Zero Packet Loss™ technology
Siemens technology for error-free communications in high EMI environments
With the increase of Ethernet networking technology in industrial environments, there comes a need for immunity to electromagnetic interference (EMI) that goes beyond what is currently delivered by commercial grade networking products. Zero Packet Loss technology is our response to this challenge.
Setting the standard for communication networks in substationsIn environments such as electric utility substations, EMI levels can be significantly higher than those of the generic industrial environment defined in the IEC 61000-6-2. In order to address this, both the International Electrotechnical Commission (IEC) and the Institute of Electrical and Electronics Engineers (IEEE) Standards Association have issued new standards.
New standards for EMI immunity
These two standards are the:
- IEC 61850-3 Communications Systems and Networks in Substations (Section 5.7)
- IEEE 1613 Standard Environmental and Testing Requirements for Communications Networking Devices in Electric Power Substations
In developing these standards, both the IEC and the IEEE Standards Association borrowed heavily from the respective standards used for protective relaying devices – critical devices used for protecting and controlling power systems. Since more and more protection relays are utilizing Ethernet communications, it was only natural that communications networking equipment also comply with the same EMI immunity requirements.
In both cases, the standards require that networking equipment operate without any physical damage, reset or latch-up during the application of a variety of destructive EMI immunity type tests.
The IEC 61850-3 protocol has multiple classifications of performance and also requires that communications used for protection functions operate without error or delays.
The IEEE 1613 defines two classes of networking devices: Class 1 devices which allow for communication errors and Class 2 devices which allow for zero errors during the application of EMI type tests.
One technology for the two standards
Siemens answer to these two new standards was to develop a technology which would withstand every EMI type test required by the IEC 61850-3, without any communications loss or delay, as well as let RUGGEDCOM solutions qualify as IEEE 1613 Class 2 Error-Free Devices.
This technology is known as Zero Packet Loss and is designed to provide the same level of EMI immunity and reliability as protective relaying devices.
When testing for Zero Packet Loss performance, a network simulator/analyzer (e.g. SmartBits) is used to generate communications traffic on all ports and at close to 100% frame rate (e.g. 99%). Industry-standard transient and EMI generators are then used to simulate EMI phenomena found in substation environments to perform the 15 EMI type tests. Ingoing and outgoing communications packets are monitored as these type tests are carried out. To be Zero Packet Loss capable, the device being tested must have zero communications errors, delays or losses during each type test.