W9128A-19-R-0016_Amendment_0001_file_4_of_4.pdf

Date Code 20181207 Instruction Manual SEL-751 Relay

Section 7 Communications

Overview A communications interface and protocol are necessary for communicating with the SEL-751 Feeder Protection Relay. A communications interface is the physical connection on a device. Once you have established a physical connec-tion, you must use a communications protocol to interact with the relay.

The first part of this section describes communications interfaces and proto-cols available with the relay, including communications interface connections.

The remainder of the section describes the ASCII commands you can use to communicate with the relay to obtain information, reports, data, or perform control functions.

Communications Interfaces The SEL-751 physical interfaces are shown in Table 7.1. Several optional SEL devices are available to provide alternative physical interfaces, including EIA-485, EIA-232 fiber-optic serial port, copper or fiber Ethernet port, single or dual redundant.

Be sure to evaluate the installation and communications necessary to integrate with existing devices before ordering your SEL-751. For example, consider the fiber-optic interface in noisy installations or for large communications dis-tances. Following is general information on possible applications of the differ-ent interfaces.

Table 7.1 SEL-751 Communications Port Interfaces

Communications Port Interfaces Location Feature

PORT F EIA-232 Front Standard

PORT 1 Option 1: 10/100BASE-T Ethernet (RJ45 connector)

Option 2: Dual, redundant 10/100 BASE-T Ethernet (Port 1A, Port 1B)

Option 3: 100BASE-FX Ethernet (LC connector)

Option 4: Dual, redundant 100BASE-FX Ethernet (Port 1A, Port 1B)

Rear Ordering Option

PORT 2 a Multimode Fiber-Optic Serial (ST connector) Rear Ordering Option

PORT 3 Option 1: EIA-232

Option 2: EIA-485

Rear Ordering Option

PORT 4 Option 1: EIA-232 or EIA-485 Serial Communications Card

Option 2: DeviceNet Communications Card b Rear Ordering Option a This port can receive the RTD measurement information from the optional external SEL-2600 RTD Module. Refer to the SEL-2600 RTD Module Instruction Manual for information on the fiber-optic interface.

b Refer to Appendix H: DeviceNet Communications for information on the DeviceNet communications card.

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SEL-751 Relay Instruction Manual Date Code 20181207

Communications Communications Interfaces

Serial (EIA-232 and EIA-485) Port

Use the EIA-232 port for communications distances as far as 15 m (49 ft) in low noise environments. Use the optional EIA-485 port for communications distances as far as 1200 m (3937 ft) maximum distance (to achieve this perfor-mance, ensure proper line termination at the receiver).

To connect a PC serial port to the relay front-panel serial port and enter relay commands, you need the following:

➤ A personal computer equipped with one available EIA-232 serial port

➤ A communications cable to connect the computer serial port to the relay serial ports

➤ Terminal emulation software to control the computer serial port

➤ An SEL-751 Relay

Some of the SEL devices available for integration or communications system robustness are included in the following list:

➤ SEL communications processors (SEL-2032, SEL-2030, SEL-2020), SEL-3530 Real-Time Automation Controller

(RTAC)

➤ SEL-2800 series fiber-optic transceivers

➤ SEL-2890 Ethernet Transceiver

➤ SEL-3010 Event Messenger

➤ SEL-2505 Remote I/O Module (with SEL-2812 compatible ST fiber-optic port) for connection to relay fiber-optic serial Port 2, or use SEL-2505 with EIA-232 (DB-9) serial port to connect to EIA-232 Port 3 on the relay

A variety of terminal emulation programs on personal computers can commu-nicate with the relay. For the best display, use VT-100 terminal emulation or the closest variation.

The default settings for all EIA-232 serial ports are as follows:

Data Rate = 9600 Data Bits = 8 Parity = N Stop Bits = 1

To change the port settings, use the SET P command (see Section 6: Settings) or the front-panel. Section 8: Front-Panel Operations provides details on mak-ing settings with the front panel.

Hardware Flow Control All EIA-232 serial ports support RTS/CTS hardware handshaking (hardware flow control). To enable hardware handshaking, use the SET P command or front-panel PORT submenu to set RTSCTS := Y. Disable hardware handshak-ing by setting RTSCTS := N.

➤ If RTSCTS := N, the relay permanently asserts the RTS line.

➤ If RTSCTS := Y, the relay deasserts RTS when it is unable to receive characters.

➤ If RTSCTS := Y, the relay does not send characters until the CTS input is asserted.

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Communications Communications Interfaces

Fiber-Optic Serial Port Use the optional fiber-optic port (Port 2) for safety and communications dis-tances as far as 1 km. For communications distances as far as 4 km, use an SEL-2812 transceiver on Port 3. Although Port 2 and the SEL-2812 are com-patible, Port 2 is less sensitive than the SEL-2812, which limits the distance to 1 km. This port can receive the RTD measurement information from the optional external SEL-2600 RTD Module.

Ethernet Port Use the Ethernet port for interfacing with an Ethernet network environment.

SEL-751 Ethernet port choices include single or dual copper or fiber-optic configurations. With dual Ethernet ports, the unit has an unmanaged Ethernet switch. Redundant configurations support automatic failover switching from the primary to the backup network if the relay detects a failure in the primary network. The basic concept in the Parallel Redundancy Protocol (PRP) mode of operation is that the Ethernet network and all traffic are fully duplicated with the two copies operating in parallel. The purpose of the protocol is to provide seamless recovery from any single Ethernet network failure. In addi-tion to failover and PRP modes, the unit can operate in a “fixed connection (to netport) mode” or in a “switched mode” (as an unmanaged switch).

You should carefully design your Ethernet network to maximize reliability, minimize system administrator efforts, and provide adequate security. SEL recommends that you work with a networking professional to design your substation Ethernet network.

Several settings control how the relay with the optional Ethernet card operates on an Ethernet network. These settings include IP addressing information, net-work port failover options, and network speed.

Use the network configuration settings shown in Table 4.85 to configure the relay for operation on an IP network and to set other parameters affecting the physical Ethernet network interface operation.

Figure 7.1 shows an example of a simple Ethernet network configuration, Figure 7.2 shows an example of an Ethernet network configuration with dual redundant connections, and Figure 7.3 shows an example of an Ethernet net-work configuration with ring structure.

Figure 7.1 Simple Ethernet Network Configuration

Cat 5 shielded twisted pair (STP) cables with RJ45 connectors

(SEL-C627/C628) for copper Ethernet ports

OR

Fiber-optic Ethernet cables with

LC connectors (SEL-C808) for fiber-optic Ethernet ports

Set Port 1 (Ethernet) settings in each relay.

NETWORK

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Communications Communications Interfaces

Figure 7.2 Ethernet Network Configuration With Dual Redundant Connections (Failover Mode)

Figure 7.3 Ethernet Network Configuration With Ring Structure (Switched Mode)

Dual Network Port Operation The SEL-751 dual Ethernet port option has two network ports. Network port failover mode enables the dual Ethernet port to operate as a single network adapter with a primary and standby physical interface. You can connect the two network ports to the same network or to different networks depending on your specific Ethernet network architecture.

Failover Mode In the failover mode operation, the relay determines the active port. To use failover mode, proceed with the following steps.

Step 1. Set NETMODE to FAILOVER.

Step 2. Set FTIME to the desired network port failover time (0.10–65.00 seconds or OFF).

Step 3. Set NETPORT to the network interface you prefer.

NETWORK

Set Port 1 (Ethernet) settings in each relay.

Cat 5 shielded twisted pair (STP) cables with RJ45 connectors (SEL-C627/C628) for copper Ethernet ports

OR

Fiber-optic Ethernet cables with LC connectors

(SEL-C808) for fiber-optic Ethernet ports

Set Port 1 (Ethernet) settings in each relay.

NETWORK

Cat 5 shielded twisted pair (STP) cables with RJ45 connectors (SEL-C627/C628) for copper Ethernet ports

OR

Fiber-optic Ethernet cables with

LC connectors (SEL-C808) for fiber-optic Ethernet ports

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Communications Communications Interfaces

On startup, the relay communicates via NETPORT (primary port) selected. If the SEL-751 detects a link failure on the primary port, it activates the standby port after the failover time, FTIME, elapses. If the link status on the primary link returns to normal before the failover time expires, the failover timer resets and uninterrupted operation continues on the primary network port.

Setting FTIME := OFF allows fast port switching (with no intentional delay).

Fast port switching can occur within one processing interval (typically 4 ms to 5 ms) and can help with IEC 61850 GOOSE performance.

After failover, while communicating via standby port, the SEL-751 checks the primary link periodically and continues checking until it detects a normal link status. The relay continues to communicate via the standby port even after the primary port returns to normal. The relay reevaluates the port of choice for communication upon a change of settings, at failure of the standby port, or upon reboot. The relay returns to operation on the primary link under those conditions if it detects a normal link status. When the active and backup links both fail, the relay alternates checking for the link status of the primary and standby ports.

Unmanaged Switch Mode If you have a network configuration where you want to use the relay as an unmanaged switch, set NETMODE to SWITCHED. In this mode, both links are enabled. The relay responds to the messages it receives on either port. All the messages received on one network port that are not addressed to the relay are transmitted out of the other port without any modifications. In this mode, the relay ignores the NETPORT setting.

Fixed Connection Mode If you have a single network and want to use only one network port, or if you have both ports connected but want to force usage of only one port for various reasons, set NETMODE to FIXED and set NETPORT to the port you want to use. Only the selected network port operates, and the other port is disabled.

PRP Connection Mode Parallel Redundancy Protocol (PRP) is part of an IEC standard for high avail-ability automation networks (IEC 62439-3). The purpose of the protocol is to provide seamless recovery from any single Ethernet network failure.

The basic concept is that the Ethernet network and all traffic are fully dupli-cated with the two copies operating in parallel.

Make the following settings for Port 1 to configure the relay for PRP mode.

➤ NETMODE = PRP

➤ PRPTOUT = desired timeout for PRP frame entry

➤ PRPADDR = PRP destination MAC address LSB (least significant byte of “01-15-4E-00-01-XX,” converted to decimal and entered as 0–255)

➤ PRPINTV = desired supervision frame transmit interval

NOTE: If you change settings for the host port in the relay and the standby network port is active, the relay resets and returns to operation on the primary port.

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Communications Communications Interfaces

When NETMODE is not set to PRP, the following settings are hidden.

Autonegotiation, Speed, and Duplex Mode Single or dual copper Ethernet ports can autonegotiate to determine the link speed and duplex mode. Accomplish this by setting the NETASPD and NETBSPD (network speed) to AUTO. You can also set single or dual copper ports to specific speeds so that you can apply them in networks with older switch devices. However, the relay ignores the speed settings for fiber Ether-net ports. The relay hardware fixes the single and dual fiber Ethernet ports to work at 100 Mbps and full duplex mode.

NETPORT Selection The NETPORT setting gives you the option of selecting the primary port of communication in failover or fixed communications modes.

TCP Keep Alive The ETCPKA setting, along with the KAIDLE, KAINTV, and KACNT set-tings, can be used to verify that the computer at the remote end of a TCP con-nection is still available. If ETCPKA is enabled and the relay does not transmit any TCP data within the interval specified by the KAIDLE setting, the relay sends a keep-alive packet to the remote computer. If the relay does not receive a response from the remote computer within the time specified by KAINTV, the keep-alive packet is re-transmitted as many as KACNT times.

After this count is reached, the relay considers the remote device no longer available, so the relay terminates the connection without waiting for the idle timer (TIDLE or FTPIDLE) to expire.

The relay monitors MMS inactivity to identify and disconnect MMS clients that have stopped communicating. You can set it from 0 to 4,200,000 seconds via the IED Properties MMS Settings in ACSELERATOR Architect SEL-5032 Software. The MMS inactivity default value is either 120 seconds or 900 seconds, depending on the relay firmware version. Setting this value to 0 disables the MMS inactivity timer. If enabled, the relay starts a timer for an MMS session after it receives an MMS request from the client on that session.

It resets the timer whenever it receives a new MMS request from that client.

When the timer runs out, the relay disconnects the MMS session, making it available for other MMS clients.

This feature was implemented in addition to the TCP keep-alive timer to spe-cifically handle MMS clients that do not disconnect properly. As there are a limited number of MMS sessions available, this ensures that misbehaving

Table 7.2 PRP Settings

Setting Prompt Setting Description Setting Range

Setting Name := Factory Default

PRP ENTRY

TIMEOUT

PRP Entry Timeout 400–10000 ms PRPTOUT := 500

PRP

DESTINATION

ADDR LSB

The multicast MAC address of PRP supervision frames is 01-15-4E-00-01-XX where XX is specified by this setting in decimal notation as 0–255

0–255 PRPADDR := 0

PRP

SUPERVISION

TX INTERVAL

PRP Supervision TX Interval 1–10 s PRPINTV := 2

NOTE: The ETCPKA setting applies to all TCP traffic on Ethernet ports, including Telnet, FTP, DNP3, IEC 61850, MMS, and C37.118 (PMU).

TCP Keep Alive is enabled with default KAIDLE, KAINTV, and KACNT settings for C37.118 (PMU) sessions even when ETCPKA = N.

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Communications Communications Interfaces

MMS clients do not take up multiple MMS sessions. Note that the MMS inac-tivity time-out can still disconnect an MMS session even if the relay receives TCP keep-alive messages from that MMS client.

IRIG-B The SEL-751 has three different physical interfaces, depending on the model options, to provide demodulated IRIG-B time-code input for time synchroni-zation. If the relay has multiple options for IRIG-B input, you can use only one input at a time. Connection diagrams for IRIG-B and settings selection are in Figure 7.4 through Figure 7.8 in this section.

Option 1: Terminals B01 and B02 This input is available on all models except models with dual Ethernet Port or Fiber-Optic Ethernet port. Refer to Figure 7.4 for a connection diagram.

B01–B02 IRIG-B input is available on all models except those with fiber-optic Ethernet or dual-copper Ethernet.

You cannot bring IRIG-B via Port 2 or 3 if you use the B01–B02 input.

Set Global setting IRIG TIME SOURCE to TIME_SRC := IRIG1.

Figure 7.4 IRIG-B Input (Relay Terminals B01–B02)

Option 2: Port 3 (EIA-232 Option Only) Connect to an SEL communications processor with SEL-C273R Cable to bring IRIG-B input with the EIA-232 port. Refer to Figure 7.5 for a connec-tion diagram. Refer to Figure 7.6 on how to connect an SEL time source (SEL-2401, SEL-2404, SEL-2407) for IRIG-B input to Port 3.

You cannot use B01–B02 input or Port 2 if you use Port 3.

Set Global setting IRIG TIME SOURCE to TIME_SRC := IRIG1.

Figure 7.5 IRIG-B Input Via EIA-232 Port 3 (SEL Communications Processor as Source)

SEL-2401

SEL-2404

or

SEL-2407

SEL-751

+ IRIG

– IRIGSEL-C962

Cable

B01

B02

BNC

SEL-2401

SEL-2404

or

SEL-2407

DB9

Port 3

EIA-232 + IRIG

(or fiber-optic equivalent)

SEL-C273A

Cable

(Figure 7.6)

SEL-751

DB9

SEL-2030

or

SEL-2032

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7.8

Communications Communications Interfaces

You cannot use B01–B02 input or Port 2 if you use Port 3.

Set Global setting IRIG TIME SOURCE to TIME_SRC := IRIG1.

Figure 7.6 IRIG-B Input Via EIA-232 Port 3 (SEL-2401/2404/2407 Time Source)

Option 3: Port 2 (Fiber-Optic Serial Port) You can use the optional fiber-optic serial Port 2 to bring IRIG-B input to the relay as shown in Figure 7.7 and Figure 7.8.

You cannot use B01–B02 input or Port 3 input if you use Port 2 for IRIG-B input.

Set Global setting IRIG TIME SOURCE to TIME_SRC := IRIG2.

Figure 7.7 IRIG-B Input Via Fiber-Optic EIA-232 Port 2 (SEL-2030/2032 Time Source)

You cannot use B01–B02 input or Port 3 input if you use Port 2 for IRIG-B input.

Set Global setting IRIG TIME SOURCE to TIME_SRC := IRIG2.

Figure 7.8 IRIG-B Input Via Fiber-Optic EIA-232 Port 2 (SEL-2401/2404/2407 Time Source)

SEL-2401

SEL-2404

or

SEL-2407

SEL-751

DB9

BNC

IED

(Any EIA-232 serial application)

SEL-C292A

Cable

SEL-C953

Cable

BNC-T Connector (3-way) SEL Part #240-1802

DB9

IRIG-B

Port 3

SEL-2812MT

SEL-2030

SEL-2032

EIA-232 Port with IRIG

DB9 Fiber-Optic Cables SEL-C805 or SEL-C807

Port 2

Set switch to EIA-232 for IRIG-B from SEL-2030 or SEL-2032

ST Connectors

SEL-751

SEL-2812MT

SEL-2401

SEL-2404

or

SEL-2407

IED

DB9

Mono-Plug Jack

Use Fiber-Optic Cables SEL-C805 or SEL-C807

SEL-C654

Cable

Port 2

Set switch to “J1” for IRIG input from SEL-2401, etc.

STST

BNC

SEL-751

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7.9

Communications Communications Interfaces

+5 Vdc Power Supply Serial port power can provide as much as 0.25 A total from all of the +5 Vdc pins. Some SEL communications devices require the +5 Vdc power supply.

This +5 Vdc power is available on Pin 1 only on EIA-232 Port 3 and EIA-232 Port 4.

Connect Your PC to the Relay

The front port of the SEL-751 is a standard female 9-pin connector with pin numbering shown in Figure 7.9. The pinout assignments for this port are shown in Table 7.3. You can connect to a standard 9-pin computer port with SEL-C234R Cable; wiring for this cable is shown in Figure 7.10. SEL-C234R Cable and other cables are available from SEL. Use the SEL-5801 Cable Selector Software to select an appropriate cable for another application. This software is available for free download from the SEL website at selinc.com.

For best performance, SEL-C234R Cable should not be more than 15 m (49 ft) long. For long-distance communications and for electrical isolation of communications ports, use the SEL family of fiber-optic transceivers. Contact SEL for more details on these devices.

Port Connector and Communications Cables

Figure 7.9 shows the front-panel EIA-232 serial port (PORT F) DB-9 connector pinout for the SEL-751.

Figure 7.9 EIA-232 DB-9 Connector Pin Numbers

Table 7.3 shows the pin functions for the EIA-232 and EIA-485 serial ports.

The following cable diagrams show several types of EIA-232 serial communi-cations cables that connect the SEL-751 to other devices. These and other cables are available from SEL. Contact the factory for more information.

Table 7.3 EIA-232/EIA-485 Serial Port Pin Functions

Pina a For EIA-485, the pin numbers represent relay terminals _O1 through _05.

PORT 3

EIA-232

PORT 3

EIA-485a

PORT 4C

EIA-232

PORT 4A

EIA-485a

PORT F

EIA-232

1 +5 Vdc +TX +5 Vdc +TX N/C

2 RXD –TX RXD –TX RXD

3 TXD +RX TXD +RX TXD

4 IRIG+ –RX N/C –RX N/C

5 GND Shield GND Shield GND

6 IRIG– N/C N/C

7 RTS RTS RTS

8 CTS CTS CTS

9 GND GND GND

12345

NOTE: Serial communications cables that are used in the SEL-751 Relays for the MIRRORED BITS protocol should have the R designation at the end of the SEL cable number instead of an A; for example, use SEL-C234R Cable instead of SEL-C234A Cable.

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Communications Communications Interfaces

Figure 7.10 SEL-C234A Cable—SEL-751 to DTE Device

Figure 7.11 SEL-C227A Cable—SEL-751 to DTE Device

Figure 7.12 SEL-C222 Cable—SEL-751 to Modem

Figure 7.13 SEL-C272A Cable—SEL-751 to SEL Communications Processor (Without IRIG-B Signal)

SEL-751 Relay

9-Pin Male D Subconnector

9-Pin Female D Subconnector

RXD

TXD

GND

CTS

TXD

RXD

GND

CTS

RTS

DCD

DTR

DSR

Pin Func.

Pin Func.Pin # Pin #

*DTE Device

*DTE = Data Terminal Equipment (Computer, Terminal, etc.)

SEL-751 Relay

9-Pin Male D Subconnector

25-Pin Female D Subconnector

GND

TXD

RXD

GND

CTS

GND

RXD

TXD

GND

RTS

CTS

DSR

DCD

DTR

Pin Func.

Pin Func.Pin # Pin #

*DTE Device

*DTE = Data Terminal Equipment (Computer, Terminal, etc.)

SEL-751 Relay

9-Pin Male D Subconnector

25-Pin Female D Subconnector

GND

TXD

RTS

RXD

CTS

GND

GND

TXD (IN)

DTR (IN)

RXD (OUT)

CD (OUT)

GND

Pin Func.

Pin Func.Pin # Pin #

**DCE Device

**DCE = Data Communications Equipment (Modem, etc.)

SEL Communications Processor

9-Pin Male D Subconnector

9-Pin Male D Subconnector

RXD

TXD

GND

RTS

CTS

TXD

RXD

GND

CTS

RTS

Pin Func.

Pin Func.Pin # Pin #

SEL-751 Relay

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7.11

Communications Communications Protocols

Figure 7.14 SEL-C273A Cable—SEL-751 to SEL Communications Processor (With IRIG-B Signal)

Figure 7.15 SEL-C387 Cable—SEL-751 to SEL-3010

Communications Protocols Protocols Although the SEL-751 supports a wide range of protocols, not all protocols are available on all ports. In addition, not all hardware options support all protocols.

Be sure to select the correct hardware to support a particular protocol. For example, if Modbus TCP is necessary for your application, be sure to order the Ethernet option for PORT 1. Table 7.4 shows the ports and the protocols available on each port.

SEL Communications Processor

9-Pin Male D Subconnector

9-Pin Male D Subconnector

RXD

TXD

IRIG+

GND

IRIG-

RTS

CTS

TXD

RXD

IRIG+

GND

IRIG-

CTS

RTS

Pin Func.

Pin Func.Pin # Pin #

SEL-751 Relay

SEL-751 Relay

DTE*

9-Pin Male D Subconnector

DCE**

9-Pin Male D Subconnector

DCD***

RXD

TXD

GND

RTS

CTS

GND

+5 Vdc (IN)

RXD (OUT)

TXD (IN)

Not Used

GND

Not Used

RTS (IN)

CTS (OUT)

GND

Pin Func.

Pin Func.Pin # Pin #

SEL-3010 Event Messenger

*DTE = Data Terminal Equipment

**DCE = Data Communications Equipment (Modem, etc.)

***DC Voltage (+5 V) not available on front-panel EIA-232 port

Table 7.4 Protocols Supported on the Various Ports (Sheet 1 of 2)

PORT Supported Protocol

PORT F SEL ASCII and Compressed ASCII Protocols, SELBOOT, File Transfer Proto-col, Modbus RTU Slave, C37.118 Protocol (synchrophasor data), and Event Messenger

PORT 1a Modbus TCP/IP, FTP, TCP/IP, IEC 61850, DNP3 LAN/WAN, SNTP, and Tel-net TCP/IP (SEL ASCII, Compressed ASCII, SEL Fast Meter, SEL Fast Operate, SEL Fast SER, SEL Fast Message, and C37.118 Protocol (synchro-phasor data)

PORT 2 SEL ASCII and Compressed ASCII Protocols, SEL Fast Meter, SEL Fast Operate, SEL Fast SER, SEL Fast Message, SEL Settings File Transfer, SEL MIRRORED BITS, DNP3, IEC 60870-5-103, Modbus RTU Slave, C37.118 Protocol (synchrophasor data), and Event Messenger

NOTE: FTP, Modbus, and DeviceNet protocols ignore the hide rules of the settings.

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7.12

Communications Communications Protocols

SEL Communications Protocols

SEL ASCII

This protocol is described in SEL ASCII Protocol and Commands on page 7.17.

SEL Compressed ASCII This protocol provides compressed versions of some of the ASCII commands.

The compressed commands are described in SEL ASCII Protocol and Com-mands, and the protocol is described in Appendix C: SEL Communications Processors.

SEL Fast Meter This protocol supports binary messages to transfer metering and digital ele-ment messages. Compressed ASCII commands that support Fast Meter are described in SEL ASCII Protocol and Commands, and the protocol is described in Appendix C: SEL Communications Processors.

SEL Fast Operate This protocol supports binary messages to transfer operation messages. The protocol is described in Appendix C: SEL Communications Processors.

SEL Fast Message This protocol uses binary messages to receive/transmit data from/to an SEL communications processor. The protocol is described in Appendix C: SEL Communications Processors.

SEL Fast SER This protocol is used to receive binary Sequential Events Record unsolicited responses. The protocol is described in Appendix C: SEL Communications Processors.

SEL Event Messenger This is an SEL ASCII protocol with 8 data bits, no parity, and 1 stop bit for transmitting data to the SEL-3010 Event Messenger. You can change only the communications speed to match the settings in the SEL-3010.

PORT 3 All the protocols supported by PORT 2

PORT 4 All the protocols supported by PORT 2 and DeviceNet a PORT 1 concurrently supports two Modbus, five DNP3 LAN/WAN, two FTP, two Telnet, one SNTP, two C37.118 Protocol (synchrophasor data), and seven IEC 61850 sessions.

Table 7.4 Protocols Supported on the Various Ports (Sheet 2 of 2)

PORT Supported Protocol

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7.13

Communications Communications Protocols

Other Supported Protocols

MIRRORED BITS Protocol The SEL-751 supports two MIRRORED BITS communications channels, desig-nated A and B. Within each MIRRORED BITS communications message for a given channel (A or B), there are eight logical data channels (1–8). You can, for example, set MBA on Port 3 of the base unit and MBB on Port 4A of the optional communications card. Attempting to set the PROTO setting to MBA, MB8A, or MBTA when Channel A is already assigned to another port (or MBB, MB8B, or MBTB when Channel B is already assigned on another port) results in the following error message: This Mirrored Bits channel is assigned to another port. After displaying the error message, the device returns to the PROTO setting for reentry. The MIRRORED BITS protocol is described in Appendix J: MIRRORED BITS Communications.

C37.118 Protocol The SEL-751 provides C37.118 protocol (synchrophasor data) support at all of the serial ports F, 2, 3, or 4. Additionally, Port 1 allows two sessions of the C37.118 protocol, which is described in Appendix I: Synchrophasors.

Modbus RTU Protocol The SEL-751 provides Modbus RTU support. Modbus is an optional protocol described in Appendix E: Modbus Communications.

Distributed Network Protocol (DNP3) The SEL-751 provides DNP3 protocol support if the option is selected. The DNP3 protocol is described in Appendix D: DNP3 Communications.

DeviceNet Protocol The SEL-751 provides DeviceNet support. DeviceNet is an optional protocol described in Appendix H: DeviceNet Communications.

IEC 60870-5-103 Protocol The SEL-751 provides IEC 60870-5-103 protocol support if the option is selected. The protocol is available on Ports 2, 3, and 4. All ports operate using the same map settings. The IEC 60870-5-103 protocol is described in Appendix G: IEC 60870-5-103 Communications.

Ethernet Protocols As with other communications interfaces, you must choose a data exchange protocol that operates over the Ethernet network link to exchange data. The relay supports FTP, Telnet, Ping, Modbus/TCP, DNP3 LAN/WAN, C37.118, and IEC 61850 protocols.

You should carefully design your Ethernet network to maximize reliability, minimize system administration effort, and provide adequate security. Work with a networking professional to design your substation Ethernet network.

File Transfer Protocol (FTP) and MMS File Transfer FTP is a standard protocol for exchanging files between computers over a TCP/IP network. The SEL-751 operates as an FTP server, presenting files to FTP clients. To create an FTP session, you need the FTP username and pass-

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7.14

Communications Communications Protocols word. The default username and password are FTPUSER and TAIL, respec-tively. The SEL-751 supports two FTP sessions at a time. Requests to establish additional FTP sessions are denied.

Manufacturing message specification (MMS) is used in IEC 61850 applica-tions and provides services for the transfer of real-time data, including files, within a substation LAN.

File Structure The file structure is organized as a directory and subdirectory tree similar to that used by Windows and other common operating systems. See Virtual File Interface on page 7.58 for information on available files.

File dates within the last 12 months are displayed with month, day, hour, and minutes. Dates older than twelve months have the year, month, and day. The times are UTC.

Access Control To log in to the FTP server, enter the value of the Port 1 setting FTPUSER as the user name in your FTP application. Enter the Port 1 setting FTPACC level password as the password in your FTP application. Note that FTP does not encrypt passwords before sending them to the server.

MMS is enabled when the Port 1 setting E61850 is set to Y. No authentication is required. MMS File Transfer is enabled when setting EMMSFS is set to Y.

If MMS Authentication is enabled via the CID file, then an authenticated con-nection must be established via MMS for MMS file transfer to take place.

Using FTP and MMS A free FTP application is included with most web browser software and PC operating systems. You can also obtain free or inexpensive FTP applications from the Internet. Once you have retrieved the necessary files, be sure to close the FTP connection using the disconnect function of your FTP application or completely closing the application. Failure to do so can cause the FTP connec-tion to remain open, which blocks subsequent connection attempts until FTPI- DLE time expires. See Appendix F: IEC 61850 Communications for information about using MMS.

Telnet Server Use the Telnet session (TPORT default setting is Port 23) to connect to the relay to use the protocols, which are described in more detail below:

➤ SEL ASCII

➤ Compressed ASCII

➤ Fast Meter

➤ Fast Operate

➤ Fast SER

Telnet is a terminal connection across a TCP/IP network that operates in a manner very similar to a direct serial port connection to one of the relay ports.

As with FTP, Telnet is a part of TCP/IP. A free Telnet application is included with most computer operating systems, or you can obtain low-cost or free Tel-net applications on the Internet.

NOTE: Use the QUIT command prior to closing the Telnet-to-Host session to set the relay to Access Level 0.

Otherwise, the relay remains at an elevated access level until TIDLE expires.

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Communications Communications Protocols

Ping Server Ping is an application based on ICMP over an IP network. A free Ping applica-tion is included with most computer operating systems. Use a Ping client with the relay Ping server to verify that your network configuration is correct.

C37.118 Protocol The SEL-751 provides C37.118 protocol (synchrophasor data) support at serial Ports F, 2, 3, or 4. Additionally, Port 1 allows two C37.118 protocol ses-sions. The C37.118 protocol is described in Appendix I: Synchrophasors.

IEC 61850

Use as many as seven sessions of MMS over a TCP network to exchange data with the relay. Use GOOSE to do real-time data exchange with as many as 64 incoming messages and 8 outgoing messages. For more details on the IEC 61850 protocol, see Appendix F: IEC 61850 Communications.

Simple Network Time Protocol (SNTP) When Port 1 (Ethernet port) setting ESNTP is not OFF, the internal clock of the relay conditionally synchronizes to the time of day served by a Network Time Protocol (NTP) server. The relay uses a simplified version of NTP called the Simple Network Time Protocol (SNTP). SNTP is not as accurate as IRIG-B. The relay can use SNTP as a less accurate primary time source, or as a backup to the higher accuracy IRIG-B time source.

SNTP as Primary or Backup Time Source If an IRIG-B time source is connected and either Relay Word bit TSOK or Relay Word bit IRIGOK asserts, then the relay synchronizes the internal time-of-day clock to the incoming IRIG-B time code signal, even if SNTP is con-figured in the relay and an NTP server is available. If the IRIG-B source is dis-connected (if both TSOK and IRIGOK deassert) then the relay synchronizes the internal time-of-day clock to the NTP server, if available. In this way, an NTP server acts either as the primary time source or as a backup time source to the more accurate IRIG-B time source.

Creating an NTP Server Three SEL application notes, available from the SEL website, describe how to create an NTP server.

➤ AN2009-10: Using an SEL-2401, SEL-2404, or SEL-2407 to Serve NTP Via the SEL-3530 RTAC

➤ AN2009-38: Using SEL Satellite-Synchronized Clocks With the SEL-3332 or SEL-3351 to Output NTP

➤ AN2010-03: Using an SEL-2401, SEL-2404, or SEL-2407 to Create a Stratum 1 Linux NTP Server

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Communications Communications Protocols

Configuring SNTP Client in the Relay To enable SNTP in the relay, make Port 1 setting ESNTP = UNICAST, MANYCAST, or BROADCAST. Table 7.5 shows each setting associated with

SNTP.

SNTP Operation Modes The following sections explain the setting associated with each SNTP opera-tion mode (UNICAST, MANYCAST, and BROADCAST).

ESNTP = UNICAST. In UNICAST mode of operation, the SNTP client in the relay requests time updates from the primary (IP address setting SNTPPSIP) or backup (IP address setting SNTPBSIP) NTP server at a rate defined by set-ting SNTPRATE. If the NTP server does not respond with the period defined by setting SNTPTO, then the relay tries the other SNTP server. When the relay successfully synchronizes to the primary NTP time server, Relay Word bit TSNTPP asserts. When the relay successfully synchronizes to the backup NTP time server, Relay Word bit TSNTPB asserts.

ESNTP = MANYCAST. In the MANYCAST mode of operation, the relay ini-tially sends an NTP request to the broadcast address contained in setting SNTPPSIP. The relay continues to broadcast requests at a rate defined by set-ting SNTPRATE. When a server replies, the relay considers that server to be the primary NTP server, and switches to UNICAST mode, asserts Relay Word bit TSNTPP, and thereafter requests updates from the primary server. If the NTP server stops responding for time SNTPTO, the relay deasserts TSNTPP and begins to broadcast requests again until the original or another server responds.

ESNTP = BROADCAST. If setting SNTPPSIP = 0.0.0.0 while setting ESNTP = BROADCAST, the relay listens for and synchronizes to any broadcasting NTP server. If setting SNTPPSIP is set to a specific IP address while setting ESNTP = BROADCAST, then the relay listens for and synchronizes to only NTP server broadcasts from that address. When synchronized, the relay asserts Relay Word bit TSNTPP. Relay Word bit TNSTPP deasserts if the relay does not receive a valid broadcast within five seconds after the period defined by setting SNTPRATE.

Table 7.5 Settings Associated With SNTP

Setting Range Description

ESNTP UNICAST,

MANYCAST,

BROADCAST

Selects the mode of operation of SNTP. See descrip-tions in SNTP Operation Modes on page 7.16.

SNTPPSIP Valid IP Address Selects primary NTP server when ENSTP = UNICAST, or broadcast address when ESNTP = MANYCAST or BROADCAST.

SNTPPSIB Valid IP Address Selects backup NTP server when ESNTP = UNICAST.

SNTPPORT 1–65534 Ethernet port used by SNTP. Leave at default value unless otherwise necessary.

SNTPRATE 15–3600 seconds Determines the rate at which the relay asks for updated time from the NTP server when ESNTP = UNICAST or MANYCAST. Determines the time the relay waits for an NTP broadcast when ENSTP = BROADCAST.

SNTPTO 5–20 seconds Determines the time the relay waits for the NTP master to respond when ENSTP = UNICAST or MANY-

CAST.

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Communications SEL ASCII Protocol and Commands

SNTP Accuracy Considerations The accuracy of the SNTP server and the networking environment limit SNTP time synchronization accuracy. You can achieve the highest degree of SNTP time synchronization by minimizing the number of switches and routers between the SNTP server and the SEL-751. You can also use network moni-toring software to ensure that average and worst-case network bandwidth use is moderate.

When installed on a network configured with one Ethernet switch between the SEL-751 and the SNTP server, and when using ESNTP = UNICAST or MANYCAST, the relay time synchronization error with the SNTP server is typically less than ±1 millisecond.

SEL ASCII Protocol and Commands Message Format SEL ASCII protocol is designed for manual and automatic communication.

All commands the relay receives must be of the following form:

A command transmitted to the relay consists of the command followed by either a CR (carriage return) or a CRLF (carriage return and line feed). You can truncate commands to the first three characters. For example, EVENT 1 <Enter> becomes EVE 1 <Enter>. Use upper- and lowercase characters without distinction, except in passwords.

The relay transmits all messages in the following format:

Each message begins with the start-of-transmission character (ASCII 02) and ends with the end-of-transmission character (ASCII 03). Each line of the mes-sage ends with a carriage return and line feed.

Software Flow Control

The relay implements XON/XOFF flow control. You can use the XON/XOFF protocol to control the relay during data transmission. When the relay receives XOFF during transmission, it pauses until it receives an XON character. If there is no message in progress when the relay receives XOFF, it blocks trans-mission of any message presented to the relay input buffer. Messages are accepted after the relay receives XON.

The relay transmits XON (ASCII hex 11) and asserts the RTS output (if hard-ware handshaking is enabled) when the relay input buffer drops below 25 percent full.

The relay transmits XOFF (ASCII hex 13) when the buffer is more than 75 percent full. If hardware handshaking is enabled, the relay deasserts the RTS output when the buffer is approximately 95 percent full. Automatic transmis-

<command><CR> or <command><CRLF>

<STX><MESSAGE LINE 1><CRLF>

<MESSAGE LINE 2><CRLF>

<LAST MESSAGE LINE><CRLF><ETX>

NOTE: The <Enter> key on most keyboards is configured to send the ASCII character 13 (<Ctrl+M>) for a carriage return. This manual instructs you to press the <Enter> key after commands to send the proper ASCII code to the SEL-751.

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7.18

Communications SEL ASCII Protocol and Commands sion sources should monitor for the XOFF character to avoid overwriting the buffer.

Transmission should terminate at the end of the message in progress when the relay receives XOFF. It can resume when the relay sends XON.

The CAN character (ASCII hex 18) aborts a pending transmission. This is useful for terminating an unwanted transmission. You can send control charac-ters from most keyboards with the following keystrokes:

➤ XOFF: <Ctrl+S> (hold down the <Ctrl> key and press S)

➤ XON: <Ctrl+Q> (hold down the <Ctrl> key and press Q)

➤ CAN: <Ctrl+X> (hold down the <Ctrl> key and press X)

Automatic Messages When the serial port AUTO setting is Y, the relay sends automatic messages to indicate specific conditions. Table 7.6 lists these messages.

Access Levels You can issue commands to the SEL-751 via the serial port or Telnet session to view metering values, change relay settings, etc. The available serial port commands are listed in the SEL-751 Relay Command Summary at the end of this manual.

You can access these commands only from the corresponding access level, as shown in the SEL-751 Relay Command Summary. The access levels are:

➤ Access Level 0 (the lowest access level)

➤ Access Level 1

➤ Access Level 2 (the highest access level)

➤ Access Level C (restricted access level, should be used under direction of SEL only)

The EPORT and MAXACC settings provide you with access controls for the corresponding port. Setting EPORT to N disables the port and hides the remaining port settings. The MAXACC setting selects the highest access level for the port.

Access Level 0 Once serial port communication is established with the SEL-751, the relay sends the following prompt:

Table 7.6 Serial Port Automatic Messages

Condition Description

Power Up The relay sends a message containing the present date and time, relay and terminal identifiers, and the Access Level 0 prompt when the relay is turned on.

Event Trigger The relay sends an event summary each time an event report is triggered. See Section 10: Analyzing Events.

Self-Test Warning or Failure

The SEL-751 sends a status report each time it detects a self-test warning or failure condition. See STATUS Command (Relay Self-Test Status) on page 7.52.

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Communications SEL ASCII Protocol and Commands

This is referred to as Access Level 0. Only a few commands are available at Access Level 0. One is the ACC command. See the SEL-751 Relay Command Summary at the end of this manual. Enter the ACC command at the Access Level 0 prompt:

The ACC command takes the SEL-751 to Access Level 1. See Access Com-mands (ACCESS, 2ACCESS, and CAL) on page 7.21 for more detail.

Access Level 1 When the SEL-751 is in Access Level 1, the relay sends the following prompt:

See the SEL-751 Relay Command Summary at the end of this manual for the commands available from Access Level 1. The relay can go to Access Level 2 from this level.

The 2AC command places the relay in Access Level 2. See Access Commands (ACCESS, 2ACCESS, and CAL) for more detail. Enter the 2AC command at the Access Level 1 prompt:

Access Level 2 When the relay is in Access Level 2, the SEL-751 sends the prompt:

See the SEL-751 Relay Command Summary at the end of this manual for the commands available from Access Level 2.

Any of the Access Level 1 commands are also available in Access Level 2.

Access Level C The CAL access level is for use exclusively by the SEL factory and SEL field service personnel to diagnose troublesome installations. A list of commands available at the CAL level is available from SEL upon request. Do not enter the CAL access level except as directed by SEL.

The CAL command allows the relay to go to Access Level C (see SEL-751 Relay Command Summary). Enter the CAL command at the Access Level 2 prompt:

=ACC <Enter>

=>2AC <Enter>

=>>CAL <Enter>

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Command Summary The SEL-751 Relay Command Summary at the end of this manual lists the serial port commands alphabetically. Much of the information available from the serial port commands is also available via the front-panel pushbuttons.

Access Level Functions

The serial port commands at the different access levels offer varying levels of control:

➤ The Access Level 0 commands provide the first layer of security. In addition, Access Level 0 supports several commands that SEL communications processors require.

➤ The Access Level 1 commands are primarily for reviewing information only (settings, metering, etc.), not changing it.

➤ The Access Level 2 commands are primarily for changing relay settings.

➤ Access Level C (restricted access level, should be used under direction of SEL only).

The SEL-751 responds with Invalid Access Level when a command is entered from an access level lower than the specified access level for the com-mand. The relay responds with Invalid Command to commands that are not available or are entered incorrectly.

Header Many of the command responses display the following header at the begin-ning:

Table 7.7 lists the header items and their definitions.

Command Explanations

This section lists ASCII commands alphabetically. Commands, command options, and command variables to enter are shown in bold. Lowercase italic letters and words in a command represent command variables that are deter-mined based on the application. For example, time t = 1 to 30 seconds, remote bit number n = 01 to 32, and level.

[RID Setting] Date: mm/dd/yyyy Time: hh:mm:ss.sss [TID Setting] Time Source: external

Table 7.7 Command Response Header Definitions

Item Definition

[RID Setting]: This is the RID (Relay Identifier) setting. The relay ships with the default setting RID = 751; see ID Settings on page 4.3.

[TID Setting]: This is the TID (Terminal Identifier) setting. The relay ships with the default setting TID = FEEDER RELAY; see ID Settings on page 4.3.

Date: This is the date when the command response was given, except for relay response to the EVE command (event), when it is the date the event occurred. You can modify the date display format (Month/ Day/Year, Year/Month/Day, or Day/Month/Year) by changing the DATE_F relay setting.

Time: This is the time when the command response was given, except for relay response to the EVE command (event), when it is the time the event occurred.

Time Source: This is internal if no time-code input is attached and external if an input is attached.

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Communications SEL ASCII Protocol and Commands

Command options appear with brief explanations about the command func-tion. Refer to the references listed with the commands for more information on the control function corresponding to the command or examples of the con-trol response to the command.

You can simplify the task of entering commands by shortening any ASCII command to the first three characters; for example, ACCESS becomes ACC.

Always send a carriage return <CR> character or a carriage return character followed by a line feed character <CR><LF> to command the control to pro-cess the ASCII command. Usually, most terminals and terminal programs interpret the Enter key as a <CR>. For example, to send the ACCESS com-mand, type ACC <Enter>.

Tables in this section show the access level(s) where the command or com-mand option is active. Access levels in this device are Access Level 0, Access Level 1, and Access Level 2.

Access Commands (ACCESS, 2ACCESS, and CAL) The ACC, 2AC, and CAL commands (see Table 7.8) provide entry to the multiple access levels. Different commands are available at the different access levels, as shown in the SEL-751 Relay Command Summary at the end of this manual. Commands ACC and 2AC are explained together because they operate similarly. See Access Levels on page 7.18 for a discussion of placing the relay in an access level.

Password Requirements You must enter passwords unless they are disabled. See PASSWORD Com-mand (Change Passwords) for the list of default passwords and for more infor-mation on changing and disabling passwords.

Access Level Attempt (Password Required). Assume the following con-ditions:

➤ Access Level 1 password is not disabled.

➤ Access Level is 0.

At the Access Level 0 prompt, enter the ACC command:

Because the password is not disabled, the relay prompts you for the Access Level 1 password:

Table 7.8 Access Commands

Command Description Access Level

ACC Moves from Access Level 0 to Access Level 1. 0

2AC Moves from Access Level 1 to Access Level 2. 1

CAL Moves from Access Level 2 to Access Level CAL. 2

=ACC <Enter>

Password: ? <Enter>

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Communications SEL ASCII Protocol and Commands

The relay is shipped with the default Access Level 1 password shown in PASS- WORD Command (Change Passwords) on page 7.45. At the prompt, enter the default password and press the <Enter> key. The relay responds with the fol-lowing:

The => prompt indicates that the relay is now in Access Level 1.

If the entered password is incorrect, the relay prompts you for the password again (Password: ?). The relay prompts for the password as many as three times. If the requested password is incorrectly entered three times, the relay pulses the SALARM Relay Word bit for one second and remains at Access Level 0 (= prompt).

Access Level Attempt (Password Not Required). Assume the following conditions:

➤ Access Level 1 password is disabled.

➤ Access Level is 0.

At the Access Level 0 prompt, enter the ACC command:

Because the password is disabled, the relay does not prompt you for a pass-word and goes directly to Access Level 1. The relay responds with the follow-ing:

The => prompt indicates that the relay is now in Access Level 1.

The two previous examples demonstrate going from Access Level 0 to Access Level 1. The procedure to go from Access Level 1 to Access Level 2 with the 2AC command entered at the access level screen prompt is similar.

You can get to Access Level C from Access Level 2 with the CAL command.

The relay pulses the SALARM Relay Word bit for one second after a success-ful Level 2 or Level C access, or if access is denied.

AFT Command (Arc-Flash Detection Channels Self-Test) Use the AFT command (Access Level 2) to initiate a self-test of the arc-flash detection channels 1 to 8. This test requires that the relay has the SELECT 2 AVI/4 AFDI card or 8 AFDI card in Slot E and the external fiber-optic con-nections are complete. The test checks the integrity of the arc-flash detection system. Figure 7.16 shows an example of the AFT command response with a 2 AVI/4 AFDI card in Slot E. Refer to Section 11: Testing and Troubleshooting for details on the arc-flash self-tests.

[RID Setting] Date: mm/dd/yyyy Time: hh:mm:ss [TID Setting] Time Source: external

Level 1

=ACC <Enter>

[RID Setting] Date: mm/dd/yyyy Time: hh:mm:ss.sss [TID Setting] Time Source: external

Level 1

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The relay asserts the AFALARM Relay Word bit when the sensor diagnostics fail or the relay detects excessive ambient light. Sensor diagnostics failure is indicated by the assertion of the AFSnDIAG Relay Word bits and excessive ambient light is indicated by the assertion of the AFSnEL Relay Word bits, where n = 1 to 8. The relay asserts the AFSnEL Relay Word bits when the cor-responding TOLn Relay Word bits stay asserted continuously for 10 seconds.

ANALOG Command Use the ANA command to test an analog output by temporarily assigning a value to an analog output channel (see Table 7.9 for the command description and format). After entering the ANA command, the device suspends normal operation of the analog output channel and scales the output to a percentage of full scale.