Physical Connection And Link Layer; Initialisation; Time Synchronisation; Spontaneous Events - GE P50 Agile P253 Technical Manual

9 SCADA Communications
This section describes how the IEC 60870-5-103 standard is applied to the P253 relay. It is not a
description of the standard itself. The level at which this section is written assumes that the reader is
already familiar with the IEC 60870-5-103 standard.
This section should provide sufficient detail to enable understanding of the standard at a level required
by most users.
The IEC 60870-5-103 interface is a master/slave interface with the device as the slave device. The
device conforms to compatibility level 2, as defined in the IEC 60870-5-103.standard.
The following IEC 60870-5-103 facilities are supported by this interface:
• Initialization (reset)

• Time synchronisation

• Event record extraction
• General interrogation

• Cyclic measurements

• General commands
• Disturbance record extraction
2.2.2

Physical Connection and Link Layer

There is just one option for IEC 60870-5-103:
• Rear serial port 1- for permanent SCADA connection via RS485
The IED address and baud rate can be selected using the front panel menu or with P50 Agile
configurator.
2.2.3

Initialisation

When the device is powered up, or if the communication parameters have been changed, a reset
command is required to initialize the communications. The device will respond to either of the two
reset commands; Reset CU or Reset FCB (Communication Unit or Frame Count Bit). The difference
between the two commands is that the Reset CU command will clear any unsent messages in the
transmit buffer, whereas the Reset FCB command does not delete any messages.
The device will respond to the reset command with an identification message ASDU 5. The Cause of
Transmission (COT) of this response will be either Reset CU or Reset FCB depending on the nature of
the reset command.
The relay will produce a power up event when the relay is powered up.
2.2.4 Time Synchronisation
The time and date can be set using the time synchronisation feature of the IEC 60870-5-103 protocol.
The device will correct the transmission delay depending on communication speed. For this,
transmission time, required for the time synchronization frame from the Master to IED, considering
current baud rate is added in the received time.
The device will correct the transmission delay depending on baud rate. If the time synchronisation
message is sent as a send/confirm message then the device will respond with a confirm message. A
time synchronisation Class 1 event will be generated/produced whether the time-synchronisation
message is sent as a send confirm or a broadcast (send/no reply) message.
2.2.5

Spontaneous Events

Events are categorized using the following information:
9-10
P50 Agile P253
P253/EN M/C