One such environment is the electric utility substation where EMI levels can be significantly higher than those of the generic industrial environment defined in IEC 61000-6-2. In order to address this risk, both the IEC and IEEE have developed and issued new standards addressing EMI immunity requirements for communications networking equipment in electric utility substations.
IEEE 1613 Standard Environmental and Testing Requirements for Communications Networking Devices in Electric Power Substations. Both groups borrowed heavily from the respective standards used for Protective Relaying devices which are critical devices used for protection and control of the power system. Since more and more protection relays are utilizing Ethernet communications it was only natural that the communications also be made to comply with the same EMI immunity requirements.
In both cases the standards have a minimum requirement that the networking equipment operate without any physical damage, reset or latch-up during the application of a variety of destructive EMI immunity type tests. IEC 61850 Protocol has multiple classifications of performance and requires that communications used for protection functions operate without error or delays. IEEE 1613 defines two classes of networking devices: Class 1 devices allow communications errors while Class 2 devices allow zero errors during the application of EMI type tests.
IEC 61850-3 EMI Immunity Type Tests
Burst (Fast Transient)
+/- 4kV @ 2.5kHz
D.C. Power Ports
A.C. Power Ports
Earth Ground Ports3
+/- 2kV line-to-earth, +/- 1kV
+/- 4kV line-to-earth, +/- 2kV
Induced (Conducted) RFI
40 A/m continuous, 1000 A/m
Voltage Dips & Interrupts
30% for 0.1s, 60% fpr 0.1s
30% for 1 period, 60% fpr 50100% for 5 periods
2.5kV common, 1kV
Mains Frequency Voltage
30V Continuous, 300V for 1s
Ripple on D.C. Power Supply
IEEE 1613 EMI Immunity Type Tests
2.5kV Common Mode @ 1MHz
2.5kV Common & Differential Mode @ 1MHz
Siemens approach was to develop technology which would withstand all of the EMI type tests required by IEC 61850-3 without experiencing any communications loss or delays and also qualify as an IEEE 1613 Class 2 Error-Free Device. This technology is known as Zero-Packet-Loss™ technology and it is designed to provide the same level of EMI immunity performance and reliability as protective relaying devices.
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 used to perform the 15 destructive EMI type tests which simulate the many types of EMI phenomena found in substation environments.
As the type tests are performed the ingoing and outgoing communications packets are monitored.
To be Zero-Packet-Loss capable the device must experience zero communications errors, delays or losses during each type test.