Zero-Packet-Loss

The proliferation of Ethernet networking technology from the office environment to industrial environments for use in real-time mission critical control applications requires a level of immunity to electromagnetic interference (EMI) well beyond what is currently delivered by commercial grade networking products. In fact even the EMI immunity requirements prescribed by IEC 61000-6-2 (Generic Standards — Immunity for Industrial Environments) are inadequate for many environments. Siemens has responded to this challenge by developing Zero-Packet-Loss technology to provide error-free communications for high EMI environments.

IEC 61850-3 and IEEE 1613 for Substations

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.

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. 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.

Type Tests Required for Zero-Packet-Loss

IEC 61850-3 EMI Immunity Type Tests

TEST

Description

Test Levels

IEC 61000-4-2

ESD

Enclosure Contact

+/- 6kV

Enclosure Air

+/- 8kV

IEC 61000-4-3

Radiated RFI

Enclosure Ports

10 V/m

IEC 61000-4-4

Burst (Fast Transient)

Signal Ports

+/- 4kV @ 2.5kHz

D.C. Power Ports

+/- 4kV

A.C. Power Ports

+/- 4kV

Earth Ground Ports3

+/- 4kV

IEC 61000-4-5

Surge

Signal Ports

line-to-line

D.C. Power Ports

+/- 2kV line-to-earth, +/- 1kV

A.C. Power Ports

+/- 4kV line-to-earth, +/- 2kV

IEC 61000-4-6

Induced (Conducted) RFI

Signal Ports

10 V

D.C. Power Ports

10 V

A.C. Power Ports

10 V

Earth Ground Ports3

10 V

IEC 61000-4-8

Magnetic Field

Enclosure Ports

40 A/m continuous, 1000 A/m

IEC 61000-4-29

Voltage Dips & Interrupts

D.C. Power Ports

30% for 0.1s, 60% fpr 0.1s

IEC 61000-4-11

A.C. Power Ports

30% for 1 period, 60% fpr 50
100% for 5 periods

IEC 61000-4-12

Dumped Oscillatory

Signal Ports

2.5kV common, 1kV

D.C. Power Ports

2.5kV common, 1kV

A.C. Power Ports

2.5kV common, 1kV

IEC 61000-4-16

Mains Frequency Voltage

Signal Ports

30V Continuous, 300V for 1s

D.C. Power Ports

30V Continuous, 300V for 1s

IEC 61000-4-17

Ripple on D.C. Power Supply

D.C. Power Ports

10%

IEEE 1613 EMI Immunity Type Tests

TEST

Description

Test Levels

IEEE C37.90.3

ESD

Enclosure Contact

+/- 8kV

Enclosure Air

+/- 15kV

IEEE C37.90.2

Radiated RFI

Enclosure Ports

35 V/m

IEEE C37.90.1

Fast Transiant

Signal Ports

+/- 4kV @ 2.5kHz

D.C. Power Ports

+/- 4kV

A.C. Power Ports

+/- 4kV

Earth Ground Ports3

+/- 4kV

IEEE C37.90.1

Oscillatory

Signal Ports

2.5kV Common Mode @ 1MHz

D.C. Power Ports

2.5kV Common & Differential Mode @ 1MHz

A.C. Power Ports

2.5kV Common & Differential Mode @ 1MHz


Zero-Packet-Loss™

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.

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 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.