Specifications

7SR242 Duobias Description Of Operation

Section 6: Other Features

6.1 Data Communications

Two communication ports, COM1 and COM2 are provided. RS485 connections are available on the terminal

blocks at the rear of the relay (COM1). A USB port, COM 2, is provided at the front of the relay for local access

using a PC.

Optionally, two additional fibre optic communication ports with ST connectors can be provided at the rear of the

relay - COM3 and COM4.

Communication is compatible with Modbus-RTU, IEC60870-5-103 FT 1.2 and optionally DNP3.0 transmission

and application standards.

Communication with the relay from a personal computer (PC) is facilitated by the REYDISP EVOLUTION

software package. The program allows the transfer of relay settings, waveform records, event records, fault data

records, Instruments/meters and control functions. REYDISP EVOLUTION is compatible with IEC60870-5-103.

Data communications operation is described in detail in Section 4 of this manual.

6.2 Maintenance

6.2.1 Output Matrix Test

The feature is available from the Relay fascia and allows the user to operate binary outputs or LEDs assigned to

relay functions.

Any protection function which is enabled in the setting menu will appear in the Output Matrix Test.

6.2.2 CB Counters

Four CB trip counters are provided:

CB1 Total Trip Count: Increments on each trip command issued.

CB1 Delta Trip Count: Additional counter which can be reset independently of the

Total Trip Counter. This can be used, for example, for

recording trip operations between visits to a substation.

CB2 Total Trip Count As CB1

CB2 Delta Trip Count: As CB1

The status of each counter can be viewed in the INSTRUMENTS mode.

Binary outputs can be mapped to each of the above counters, these outputs are energised when the

user defined Count Target is reached.

6.2.3 I

t CB Wear

CB1 and CB2 wear counters are also provided:

t CB1 Wear: Provides an estimate of contact wear and maintenance

requirements. The algorithm works on a per phase basis,

measuring the arcing current during faults. The I

t value at

the time of trip is added to the previously stored value and an

alarm is given when any one of the three phase running

counts exceeds the set Alarm limit . The t value is the time

between CB contacts separation when an arc is formed,

Separation Time, and the CB Clearance time.