ABB REF620 NBFNAANNNDA1BBN1XF Feeder protection and control

Ethernet redundancy

IEC 61850 specifies a network redundancy scheme that improves the system availability

for substation communication. It is based on two complementary protocols defined in the

IEC 62439-3:2012 standard: parallel redundancy protocol PRP and high-availability

seamless redundancy HSR protocol. Both protocols rely on the duplication of all

transmitted information via two Ethernet ports for one logical network connection.

Therefore, both are able to overcome the failure of a link or switch with a zero-switchover

time, thus fulfilling the stringent real-time requirements for the substation automation

horizontal communication and time synchronization.

PRP specifies that each device is connected in parallel to two local area networks. HSR

applies the PRP principle to rings and to the rings of rings to achieve cost-effective

redundancy. Thus, each device incorporates a switch element that forwards frames from

port to port. The HSR/PRP option is available for all 615 series protection relays.

However, RED615 supports this option only over fiber optics.

PRP

Each PRP node, called a double attached node with PRP (DAN), is attached to two

independent LANs operated in parallel. These parallel networks in PRP are called LAN

A and LAN B. The networks are completely separated to ensure failure independence, and

they can have different topologies. Both networks operate in parallel, 

thus providing zerotime recovery and continuous checking of redundancy to avoid communication failures.

Non-PRP nodes, called single attached nodes (SANs), are either attached to one network

only (and can therefore communicate only with DANs and SANs attached to the same

network), or are attached through a redundancy box, a device that behaves like a DAN.

additional PRP information from the Ethernet frames. In some cases, default PC

workstation adapters are not able to handle the maximum-length Ethernet frames with the

PRP trailer.

Protection functions

The IED offers directional and non-directional overcurrent and thermal overload protection as

well as directional and non-directional earth-fault protection. 

Some standard configurations allow as an option admittance-based, harmonics-based or wattmetric-based earth-fault protection to be

used in addition to directional earth-fault protection. 

Further, the IED features sensitive earth-fault protection, phase discontinuity protection, transient/intermittent earth-fault protection, 

overvoltage and undervoltage protection, residual overvoltage protection, positive-sequence undervoltage 

and negativesequence overvoltage protection. 

The outstanding I/O capability in REC670 enables control of several bays with complete measurement with only one IED. 

For instance, one REC670 IED is capable of handling control of all apparatuses 

in one entire diameter in 1 ½ breaker arrangement including breaker failure protection for all breakers.