PCS 978s x communication protocol manual EN overseas general x r1 00

1 Communication Modules Introduction of communication interfaces application in different network structures and serial connection modes.. 1 Communication Modules Date: 10 January 2020

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Although every reasonable effort is made to present current and accurate information, this document does not purport to cover all details or variations in equipment nor provide for every possible contingency to be met in connection with installation, operation, or maintenance Should further information be desired or should particular problems arise which are not covered sufficiently for your purposes, please do not hesitate to contact us

Preface

Date: 10 January 2020

Preface

About This Document

This manual describes the network structures and the communication protocols supported by the device

To start using this manual, user should have a basic knowledge of communication in substation automation system (SAS) and of the specific communication protocols along with the basic operation methods of the PCS-Studio configuration tool for PCS S series IEDs

Safety Information

This manual is not a complete index of all safety measures required for operation of the equipment (module or device) However, it comprises important information that must be followed for personal safety, as well as to avoid material damage Information is highlighted and illustrated as follows according to the degree of danger:

Indicates an imminently hazardous situation that, if not avoided, will result

in death or serious injury

Indicates a potentially hazardous situation that, if not avoided, could result

in death or serious injury

Indicates a potentially hazardous situation that, if not avoided, may result in

minor or moderate injury or equipment damage

Indicates that property damage can result if the measures specified are not

taken

Important information about the product, please pay attention to avoid undesired result

Instructions and Warnings

The following hazard statements apply to this device

Disconnect or de-energize all external connections BEFORE opening this

device Contact with hazardous voltages and currents inside this device can cause electrical shock resulting in injury or death

Contact with instrument terminals can cause electrical shock that can result

in injury or death

Use of this equipment in a manner other than specified in this manual can impair operator safety safeguards provided by this equipment

Have ONLY qualified personnel service this equipment If you are not

qualified to service this equipment, you can injure yourself or others, or cause equipment damage

This device is shipped with default passwords Default passwords should

be changed to private passwords at installation Failure to change each default password to a private password may allow unauthorized access

NR shall not be responsible for any damage resulting from unauthorized access

DO NOT look into the fibre (laser) ports/connectors

DO NOT look into the end of an optical cable connected to an optical

output

DO NOT perform any procedures or adjustments that this instruction

manual does not describe

During installation, maintenance, or testing of the optical ports, ONLY use the test equipment qualified for Class 1 laser products!

Preface

Date: 10 January 2020

Incorporated components, such as LEDs, transceivers, and laser emitters,

are NOT user serviceable Return units to NR for repair or replacement

Equipment components are SENSITIVE to electrostatic discharge (ESD)

Undetectable permanent damage can result if you do not use proper ESD procedures Ground yourself, your work surface, and this equipment

BEFORE removing any cover from this equipment If your facility is not

equipped to work with these components, contact NR about returning this device and related NR equipment for service

Insufficiently rated insulation can deteriorate under abnormal operating conditions and cause equipment damage For external circuits, use wiring

of SUFFICIENTLYRATED insulation that will not break down under

abnormal operating conditions

SEVERE power and ground problems can occur on the communications

ports of this equipment as a result of using non-standard cables Please use the wiring method recommended in the manual for communication terminals

DO NOT connect power to the device until you have completed these

procedures and receive instruction to apply power Equipment damage can result otherwise

Use of controls or adjustments, or performance of procedures other than

those specified herein, may RESULT IN hazardous radiation exposure

The firmware may be upgraded to add new features or enhance/modify

existing features, please MAKE SURE that the version of this manual is

compatible with the product in your hand

Document Conventions

 Menu path is connected with the right arrow "→" and bold

For example: the access path of protection settings is: Main Menu → Settings → Protection Settings

 Settings out of list should be placed in brackets

For example: the system setting [Opt_SysFreq]

 Cross-references are presented in italics

For example: refer to Figure 1.1-1, refer to Table 1.1-1, reference to Section 1.1

 Binary input signals, binary output signals, analogue quantities, LED lights, buttons, and other fixed meanings, should be written in double quotes and bold

For example: press the "ENT" button

1 Communication Modules

Introduction of communication interfaces application in different network structures and serial connection modes

2 IEC 61850

Introduction of IEC 61850 protocol, including protocol characteristics and properties

Instantiation application of communication between the client and the server for substation automation via the IEC 61850 Manufacturing Message Specification (MMS) protocol, cross communication between devices via Generic Object-Oriented Substation Event (GOOSE) messages and IEC 61850-9-2 SV implementation

3 DNP3

Instruction of DNP3 protocol characteristics and properties, especially the application layer with implementation information

Introduction of Modbus protocol main function codes.

Document Revision History

P/N: ZL_PCS-978S_X_Communication Protocol Manual_EN_Overseas General_X

1.3 Ethernet Network Structures 1-3

1.3.1 Standardized Ethernet Cable 1-4

1.3.2 Relevant Settings 1-4

1.3.3 Ethernet Interface Setup 1-5

1.3.4 Port Bonding Operation 1-6

1

1 Communication Modules

Date: 10 January 2020

1

This section outlines the communication modules of device This device supports a choice of

multiple protocols via rear interfaces on communication modules The protocols are selected and

configured by setting or configuration file via the configuration tool PCS-Studio

It should be noted that the description contained within this manual do not aim to fully detail

protocols The relevant documentation for protocols should be referred to for such goal This

manual serves to describe the specific implementation of protocols in this device

1.1 CPU Module

This device is usually ordered with factory-installed communication modules Yet a communication

module, such as the CPU module or the NET-DSP module, can also be installed and replaced in

the device afterwards

The NR6106 CPU module can be installed on device rack The sub-models of this module

correspond to different communication interfaces or device variants

1

2

3

4

Figure 1.1-1 View of CPU module

1 Ethernet interfaces LAN1 and LAN2

1 2 Ethernet interfaces LAN3 and LAN4

3 Serial interfaces: 10-terminal connector, 2*EIA-485 ports and 1*EIA-485/TTL port for clock synchronization

4 Debugging interface: RJ45 port

2 × optical Ethernet, 100Base-FX, 1310 nm, duplex LC plug, 2 km via 50 µm or

1 Communication Modules

Date: 10 January 2020

1 Communication interface

Additional Ethernet protocols and services

HSR (High-availability uninterruptible ring redundancy) ●

1.3 Ethernet Network Structures

The Ethernet interfaces have an integrated switching function This makes it possible to integrate

the device with third-party components into almost all network structures, which are independent

of the communication protocols such as IEC 61850, IEC 60870-5-103 and DNP3

Devices are integrated into superior network structures via switches Each switch provides several

interfaces to connect to devices and other switches in the superior network The superior network

operates on the basis of RSTP (Rapid Spanning Tree Protocol) which leads to a network or a ring

of such network switches This results in a variety of possible structures of superior network

WLAN

Substation LAN

Control Centre LAN

Remote Monitoring

IEDs

Figure 1.3-1 Ethernet network structure

1 1.3.1 Standardized Ethernet Cable

It is recommended to use screened twisted multi-strand network cable (category 5) as the communication cable

Figure 1.3-2 Ethernet cable

1.3.2 Relevant Settings

The communication settings that are relevant to Ethernet network are listed in the following table Refer to the device technical manual and setting guide for more detail about the parameterization, such as IP address, gateway address, etc

Access path: Main Menu  Settings  Global Settings  Comm Settings General Comm Settings

- - Subnet mask of Ethernet port B

En_LAN2 Enabled Disabled or Enabled - - Put Ethernet port B into service

1 Communication Modules

Date: 10 January 2020

1

En_LAN4 Disabled Disabled or Enabled - - Put Ethernet port D into service

B01.Opt_NetMode Normal

Normal;

1-2:Normal, 3-4:HSR;

1-2:Normal, 3-4:PRP;

1-2:Normal, 3-4:RSTP;

- - The network method of the CPU

module located in slot No.1

1.3.3 Ethernet Interface Setup

The communication modules and interfaces are available in both electrical and optical versions

There is no difference in interface setup through both versions To communicate with the device

via a PC for monitoring, a connection must be established

Ensure that the device and PC are in the same network segment by setting the IP address

[IP_LAN*] and subnet mask [Mask_LAN*] of corresponding Ethernet interfaces

1

LAN1 LAN2

LAN3 LAN4

Figure 1.3-3 Ethernet interfaces

For example, to establish a connection between PC and the device first Ethernet interface, set the

IP address and subnet mask of PC to be “198.87.96.102” and “255.255.255.0”.The IP address and subnet mask of device should be [IP_LAN1]= 198.87.96.*** (** can be any integer from 0 to 255 except 102 or any other appeared number), [Mask_LAN1]=255.255.255.0

The logic setting [En_LAN*] must be enabled to activate the corresponding Ethernet interface of device

1.3.4 Port Bonding Operation

Use the setting [Cfg_NetPorts_Bond] to set the channel bonding arrangement of two Ethernet ports in station level communication link In this operating mode, two interfaces of the device are bonding with the same IP and MAC address The 1st interface that detects a connection with switch is active and takes the responsibility of the entire data transmission via such connection The 2nd interface whose link status is monitored operates on standby If the active connection fails, the device switches to the 2nd one rapidly

For redundancy or increased throughput of the communication, dual network structure may be adopted along with channel bonding technology These two bonded interfaces, who share the identical IP address and MAC address, work in Active-Standby mode If the link via active interface

The value of this setting represents a 4-bits binary number Each bit represents a corresponding

Ethernet port's bonding status Use the following map to decide the specific setting value

Additionally, the default value "0" means the channel bonding function is deactivated

Ethernet port 1

Setting Value Bit0

1 1 0

0

Ethernet port 1

Setting Value Bit0

1 0 1 0

Ethernet port 1

Setting Value Bit0

1 0 0 1

Ethernet port 2

Setting Value Bit0

0 1 1

0

Ethernet port 2

Setting Value Bit0

0 1 0 1

Ethernet port 3

Setting Value Bit0

0 0 1 1

Ethernet port 1: Bit0, Ethernet port 2: Bit1, Ethernet port 3: Bit2, Ethernet port 4: Bit3

The Active-Standby mode switching logic is:

Take the device Ethernet ports 1 & 2 for example and assume that P1 is connected to NET1 while

P2 is connected to NET2

 After the device is powered on, only P1 is activated when both NET1 and NET2 are normal

 If NET1 is abnormal, P2 will be activated if NET2 is normal

 If NET1 is abnormal, P2 cannot be activated if NET2 is also abnormal The device will keep

trying on P1

 If P2 is working, the device will maintain this state even if NET1 has been restored to normal

It will be switched to P1 only if NET2 is abnormal

1.3.5 Star-shaped

Set [B01.Opt_NetMode] to be "Normal" to activate this structure

Only one interface of the device is connected to switch Multiple devices are connected to the switch in

a star-shaped connection

1

Substation LAN

IEDs

Figure 1.3-4 Star-shaped network

The unique connection provides no redundancy Practically, it is suggested to use another interface to create a dual star network or at least use the port bonding method to enhance the redundancy of network structure

1.3.6 PRP Structure

Set [B01.Opt_NetMode] to be "1-2: Normal, 3-4: PRP" to activate this structure with the device No.3

& 4 Ethernet interfaces

According to IEC 62439-3, the PRP (Parallel Redundancy Protocol) provides communication over two independent networks simultaneously If there is an interruption in communication on either network A or network B, the data exchange continues without problems on the other network Thus, it assures that there is no interruption It is recommended to use a non-PRP device, such as debugging PC, with a Redundancy Box (RedBox) in a PRP network

The PRP nodes connect to two independent networks, and send two copies of the same packet to both networks Both networks transmit these messages to receiving nodes, while receiving nodes accept the first packet and discard the second The receiving nodes make a redundant handling at data link layer to realize redundant message receiving and then transmit data to application layer

PRP Activated

LAN A LAN B

PRP Activated

LAN A LAN B

PRP Activated

LAN A LAN B

PRP Activated

IEDs

Figure 1.3-5 PRP structure network

Each node has two interfaces that operate in parallel and that are attached to the same upper

layers of the communication stack through the Link Redundancy Entity (LRE) For the basic

communication, the LRE presents toward its upper layers the same interface as a non-redundant

network adapter, so the upper layers are unaware of redundancy

When receiving a frame from the node’s upper layers, the LRE appends to the frame a

Redundancy Check Trailer (RCT) containing a sequence number and sends the frame through

both its ports at nearly the same time The two frames are nearly identical except for the LAN

identifier (and the checksum)

When receiving frames from the network, the LRE forwards the first received frame of a pair to its

node’s upper layers and discards the duplicate frame (if it arrives) It removes the RCT if required

1

Figure 1.3-6 Operation mechanism of device PRP interfaces

1.3.7 HSR Structure

Set [B01.Opt_NetMode] to be "1-2: Normal, 3-4: HSR" to activate this structure with the device No.3

& 4 Ethernet interfaces

According to IEC 62439-3, devices operate in hand-in-hand mode in the HSR (High Availability Seamless Redundancy Protocol) structure to form rings with switches If an interruption in communication occurs in a network, a seamless switchover takes place It is recommended to use

a non-HSR device, such as debugging PC, with a Redundancy Box (RedBox) in an HSR network

HSR nodes send a copy of data to application layer The data is copied at data link layer and is transmitted from Port A and Port B via different physical link

HSR ring transmission through two-way link ensures the redundancy of data When a link fails, a message can be transmitted to the receiving device from another loop, and there is no network reconstruction time There is no switching network, and forwarding through the device However, forwarding device has a forwarding delay time per level, so the total forwarding delay is great

HSR Activated

LAN A LAN B

HSR Activated

LAN A LAN B

HSR Activated

IEDs

Substation LAN

Figure 1.3-7 HSR structure network

Each HSR node has two interfaces arranged in a ring Source nodes send packets over both

interfaces Each node transmits unreceived frames from interface A to interface B and vice versa

The source node removes frames it receives that it injected into the ring

Each HSR node receives two copies of the same packet, and accepts the first packet and discards

the second The accepted packet is transmitted to application layer

For P2P messages (e.g TCP messages), receiving node will stop transmitting after receiving the

message For multicast or broadcast message, if the message comes from itself, receiving node

will stop transmitting after receiving the message If the message comes from other nodes,

receiving node will transmit it to another interface after receiving the message, i.e., receiving

message from interface A and transmitting message to interface B

1.3.8 RSTP Ring Structure

Set [B01.Opt_NetMode] to be "1-2: Normal, 3-4: RSTP" to activate this structure with the device No.3

& 4 Ethernet interfaces

Devices participate in a ring structure via two interfaces Data is transmitted one by one in the ring

until it reaches its intended destination If the ring structure breaks at a point, stars show up upon

the switch quantity Thanks to RSTP mechanism, the communication may function continuously

without interruption However, a second fault in one star cannot be ignored

RSTP Activated

LAN A LAN B

RSTP Activated

LAN A LAN B

1.4.1 Relevant Settings

The communication settings that are relevant to serial connection are listed in the following table Refer to the device technical manual and setting guide for more detail about the parameterization, such as protocol option, address, baud rate, etc

Access path: Main Menu  Settings  Global Settings  Comm Settings General Comm Settings

- - Communication protocol of rear RS-485 serial port 1

Protocol_RS485-2 IEC103

IEC103 Modbus DNP

- - Communication protocol of rear RS-485 serial port 2

- bps Baud rate of rear RS-485 serial port 2

Addr_RS485-1 100 0~255 1 - Communication address between the device and the

SCADA or RTU via RS-485 serial port 1

Addr_RS485-2 100 0~255 1 - Communication address between the device and the

SCADA or RTU via RS-485 serial port 2

1.4.2 EIA-485 Interface

Each EIA-485 port has three terminals (two for data transmission and one for signal grounding) It

provides a half-duplex fully isolated serial connection to the device The connection is polarized

and whilst the connection diagram indicates the polarization of terminals Notice that there is no

agreed definition of which terminal is which If the master is unable to communicate with the device

and the communication settings match, it is possible that the two-wire connection is reversed

1 Communication Modules

Date: 10 January 2020

1

topology is not part of the EIA-485 standard and is forbidden

Two-core screened cable is recommended The specification of the cable will be dependent on the

application, although a multi-strand 0.5mm2 per core is normally adequate Total cable length must

not exceed 500m The screen must be continuous and grounded at only one end (normally at the

master connection point) For both safety and noise reasons, it is important to avoid circulating

current, especially when the cable runs between buildings

The signal grounding connection must have continuity for the benefit of all devices connected to

the bus At no stage must it be connected to the cables screen or to the device chassis This is for

both safety and noise reasons

1.4.2.3 Biasing

It may also be necessary to bias the signal wires to prevent jabber Jabber occurs when the signal

level has an indeterminate state because the bus is not being actively driven This may occur

when all slaves are in receiving mode and the master is slow to turn from receiving mode to

transmitting mode This may be because the master purposefully waits in receiving mode, or even

in a high impedance state, until it has something to transmit Jabber causes the receiving device(s)

to miss the first bits of the first character in the packet, which results in rejecting message and no

consequential responding of slave The symptoms of these are poor response time (due to retries),

increasing message errors, erratic communication and even a complete failure of communication

Biasing requires that the signal wires be weakly pulled to a defined voltage level of approximate 1V

There should only be one bias point on the bus, which is best situated at the master connection

point The DC source used for the bias must be clean, otherwise noise will be injected Note that

some devices may (optionally) be able to provide the bus bias, in which case external components

will not be required

It is extremely important that the 120Ω termination resistors are fitted

Failure to do so will result in an excessive bias voltage that may damage the devices connected to the bus

As the field voltage is much higher than that required, NR cannot assume responsibility for any damage that may occur to a device connected to the network as a result of incorrect application of this voltage

Ensure that the field voltage is not being used for other purposes (i.e

powering logic inputs) as this may cause noise to be passed to the communication network

1

2.3 MMS Communication Network Deployment 2-4

2.3.1 Dual-net Full Duplex Mode Sharing the Same RCB Instance 2-5

2.3.2 Dual-net Hot-standby Mode Sharing the Same RCB Instance 2-6

2.3.3 Dual-net Full Duplex Mode with 2 Independent RCB Instances 2-7

2.4 Server Data Organization 2-8

2.4.1 Digital Status Values 2-8

2.4.2 Analog Values 2-8

2.4.3 Protection Logical Nodes 2-10

2.4.4 LLN0 and Other Logical Nodes 2-10

2.5 Server Features and Configuration 2-11

2.6.1 For IEC 61850 Edition 1 2-19

2.6.2 For IEC 61850 Edition 2 2-25

2.7 Logical Nodes Table 2-31

2.7.1 For IEC 61850 Edition 1 2-32

2.7.2 For IEC 61850 Edition 2 2-36

2

2 IEC 61850

2

Date: 10 January 2020

The IEC 61850 standard is the result of years of work by electric utilities and vendors of electronic

equipment to produce standardized communications systems It is a series of standards

describing client/server and peer-to-peer communications, substation design and configuration,

testing, environmental and project standards The complete set includes:

 IEC 61850-1: Introduction and overview

 IEC 61850-2: Glossary

 IEC 61850-3: General requirements

 IEC 61850-4: System and project management

 IEC 61850-5: Communications and requirements for functions and device models

 IEC 61850-6: Configuration description language for communication in electrical substations

related to IEDs

 IEC 61850-7-1: Basic communication structure for substation and feeder equipment–

Principles and models

 IEC 61850-7-2: Basic communication structure for substation and feeder equipment - Abstract

communication service interface (ACSI)

 IEC 61850-7-3: Basic communication structure for substation and feeder equipment–

Common data classes

 IEC 61850-7-4: Basic communication structure for substation and feeder equipment–

Compatible logical node classes and data classes

 IEC 61850-8-1: Specific Communication Service Mapping (SCSM) – Mappings to MMS (ISO

9506-1 and ISO 9506-2) and to ISO/IEC 8802-3

 IEC 61850-9-1: Specific Communication Service Mapping (SCSM) – Sampled values over

serial unidirectional multidrop point to point link

 IEC 61850-9-2: Specific Communication Service Mapping (SCSM) – Sampled values over

ISO/IEC 8802-3

 IEC 61850-10: Conformance testing

These documents can be obtained from the IEC (https://www.iec.ch) It is strongly recommended

that all those involved with any IEC 61850 implementation obtain this document set

2

IEC 61850 Ed1&2 MMS GOOSE

IEC 61850-9-2 SV GOOSE

RTU SCADA

Optical

Electronic CT/VT

Merging Unit

Electrical or Optical

Figure 2.3-1 Application of IEC 61850 in substation

2.1 Relevant Settings

For the adoption of IEC 61850 as the communication protocol of this device, select the option

“Basic + IEC 61850 (Edition 1.0 or Edition 2.0)” in the following path through the PCS-Studio configuration tool: Project Name → IED Name → Device Setup → Global Config → MOT → S3 Protocol

Use the "Edition" option to determine the IEC 61850 protocol edition through the path: Project Name → Communication → IEC61850

2 IEC 61850

2

Date: 10 January 2020

Besides the general Ethernet network settings, such IP address, MAC address, the settings that

are relevant to this protocol are listed in the following table Refer to the device technical manual

and setting guide for more detail about the parameterization, such as IED name, dual network

operation mode, etc

Access path: Main Menu  Settings  Global Settings  Comm Settings  IEC61850

ThAbs_Measmt 0.02 0.001~0.5 0.001 - Measurement values zero drift

Opt_DualNetMode_MMS SingleNet

SingleNet HotStdby ColdStdby

It is used to select the network mode of MMS network for the communication with SCADA

SingleNet: Single network HotStdby: Hot standby mode (always two ports in service)

ColdStdby: Cold standby mode (only one port in service)

IEDNAME TEMPLATE - - - Logical device name in IEC 61850

2

2.2 Communication Profiles

This device supports IEC 61850 server services over TCP/IP communication protocol stacks The TCP/IP profile requires the device to have an IP address to establish communications These addresses are located in the path: Main Menu → Settings→ Global Settings→ Comm Settings

→ General Comm Settings

 MMS protocol

IEC 61850 specifies the use of the Manufacturing Message Specification (MMS) at the upper (application) layer for transfer of real-time data This protocol has been in existence for a number of years and provides a set of services suitable for the transfer of data within a substation LAN environment IEC 61850-7-2 abstract services and objects are mapped to actual MMS protocol services in IEC 61850-8-1

 Client/server

This is a connection-oriented type of communication The connection is initiated by the client, and communication activity is controlled by the client IEC 61850 clients are often substation computers running HMI programs or SOE logging software Servers are usually substation equipment such as protection relays, meters, RTUs, transformer, tap changers, or bay controllers

 Peer-to-peer

This is a non-connection-oriented, high speed type of communication usually between substation equipment, such as protection relays, intelligent terminal GOOSE is the method of peer-to-peer communication

 Substation configuration language (SCL)

A substation configuration language is a number of files used to describe IED configurations and communication systems according to IEC 61850-5 and IEC 61850-7 Each configured device has an IED Capability Description (ICD) file and a Configured IED Description (CID) file The substation single line information is stored in a System Specification Description (SSD) file The entire substation configuration is stored in a Substation Configuration Description (SCD) file The SCD file is the combination of the individual ICD files and the SSD file, moreover, add communication system parameters (MMS, GOOSE, control block, SV control block) and the connection relationship of GOOSE and SV to SCD file

2.3 MMS Communication Network Deployment

In order to enhance the stability and reliability of SAS, dual-MMS Ethernet is widely adopted This section is applied to introduce the details of dual-MMS Ethernet technology Generally, single-MMS Ethernet is recommended to be adopted in the SAS of 110kV and lower voltage levels,

Client-server mode is adopted: clients (SCADA, control centre and etc.) communicate with the

IEDs via MMS communication network, and the IEDs operate as the servers IEDs are connected

to clients passively, and they can interact with the clients according to the configuration and the

issued command of the clients

Three modes for dual-MMS Ethernet (abbreviated as dual-net) are provided as below

Hereinafter, the normal operation status of net means the physical link and TCP link are both ok The abnormal operation status of net means physical link or TCP link is broken

2.3.1 Dual-net Full Duplex Mode Sharing the Same RCB Instance

Client

IED (Server)

Report Control Block

Report Instance 1 RptEna = true

Abnormal operation status

Figure 2.3-1 Dual-net full duplex mode sharing the RCB block instance

Net A and Net B share the same report control block (abbreviated as RCB) enabled by the client

IED sends undifferentiated date through dual-net to the clients If one net is physically

disconnected, the flag of RCB instance (i.e.: “RptEna” in above figure) is still “true” Only when

both Net A and Net B are disconnected, the flag of the RCB instance will automatically change to

“false”

In normal operation status of this mode, IED provides the same MMS service for Net A and Net B

If one net is physically disconnected (i.e.: “Abnormal operation status” in above figure), the

working mode will switch to single-net mode seamlessly and immediately Network communication

2

supervision is unnecessary here, and Buffered Report Control Block (abbreviated as BRCB) need not to be used On the other net, date alternation works normally Therefore, MMS service can interact normally without interruption This mode ensures no data loss during one net is in abnormal operation status

In this mode, one report will be transmitted twice via dual nets for the same report instance, so the client needs to distinguish whether two reports are same according to corresponding EntryIDs

2.3.2 Dual-net Hot-standby Mode Sharing the Same RCB Instance

Client

IED (Server)

Report Control Block

Report Instance 1 RptEna = true

TCP Link Main MMS Link

Normal operation status

Client

IED (Server)

Report Control Block

Report Instance 1 RptEna = true

Abnormal operation status

Standby MMS Link

Figure 2.3-2 Dual-net hot-standby mode sharing the same RCB instance

In this mode, the MMS service is provided on main MMS link, no MMS service interacts on the standby MMS link The definitions of two links are as follows:

 Main MMS Link: Physically connected, TCP level connected, MMS report service available

 Standby MMS Link: Physically connected, TCP level connected, MMS report service not available

If the main net fails to operate (i.e.: “Abnormal operation status” in the above figure), the IED will set “RptEna” to “false” Meanwhile the client will detect the failure by heartbeat message or

“keep-alive”, it will automatically enable the RCB instance by setting “RptEna” back to “true” through standby MMS link By the buffer function of BRCB, the IED can provide uninterrupted MMS service on the standby net However, the differences of BRCB standards among different manufacturers may cause data loss Moreover, if duration of net switch is too long, the data loss is positively as the capacity of BRCB’s buffer function is limited

For example, if the subnet mask is “255.255.0.0”, network prefix of Net A is

“198.120.0.0”, network prefix of Net B is “198.121.0.0”, Net A IP address of the IED is “198.120.1.2”, and then Net B IP address of the IED must be configured as “198.121.1.2”, i.e., Net A IED host address =1x256+2=258, Net B IED host address =1x256+2=258, Net A IED host address equals to Net B IED host address

2.3.3 Dual-net Full Duplex Mode with 2 Independent RCB Instances

Client

IED (Server)

Report Control Block

Report Instance 1 RptEna = true

Report Instance 2 RptEna = true

Figure 2.3-3 Dual-net full duplex mode with 2 independent RCB instances

In this mode, IED provides 2 report instances for each RCB, Net A and Net B work independently

from each other, failures of any net will not affect the other net at all Tow report instances are

required for each client Therefore, the IED may be unable to provide enough report instances if

there are too many clients

Net A and Net B send the same report separately when they operate normally To ensure no

repeated data is saved into database, massive calculation is required for the client

Moreover, accurate clock synchronization of the IED is required to distinguish whether 2 reports

are the same report according to the timestamps Clock synchronization error of the IED may lead

to report loss/redundancy

As a conclusion, for the second mode, it’s difficult to realize seamless switchover between dual

nets, however, for the third mode, the IED may be unable to provide enough report instances if too

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many clients are applied on site Considering client treatment and IED implementation, the first mode (Dual-net full duplex mode sharing the same report instance) is recommended for MMS communication network deployment

2.4 Server Data Organization

IEC61850 defines an object-oriented approach to data and services An IEC61850 physical device can contain one or more logical device(s) (for proxy) Each logical device can contain many logical nodes Each logical node can contain many data objects Each data object is composed of data attributes and data attribute components Services are available at each level for performing various functions, such as reading, writing, control commands, and reporting

Each IED represents one IEC 61850 physical device The physical device contains one or more logical device(s), and the logical device contains many logical nodes The logical node LPHD contains information about the IED physical device The logical node LLN0 contains common information about the IED logical device

2.4.1 Digital Status Values

The GGIO logical node is available in this device to provide access to digital status points (including general I/O inputs and warnings) and associated timestamps and quality flags The data content must be configured before the data can be used GGIO provides digital status points for access by clients It is intended that clients use GGIO in order to access digital status values from

in this device Clients can utilize the IEC61850 buffered reporting features available from GGIO in order to build sequence of events (abbreviated as SOE) logs and HMI display screens Buffered reporting should generally be used for SOE logs since the buffering capability reduces the chances of missing data state changes All needed status data objects are transmitted to HMI clients via buffered reporting, and the corresponding buffered reporting control block (abbreviated

as BRCB) is defined in LLN0

2.4.2 Analog Values

Most of analog measured values are available through the MMXU logical nodes, and metering values in MMTR, the else in MMXN, MSQI and so on Each MMXU logical node provides data from an IED current/voltage “source” There is one MMXU available for each configurable source MMXU1 provides data from CT/VT source 1(usually for protection purpose), and MMXU2 provides data from CT/VT source 2 (usually for monitor and display purpose) All these analog data objects are transmitted to HMI clients via unbuffered reporting periodically, and the corresponding unbuffered reporting control block (URCB) is defined in LLN0

 MMXUx logical nodes provide the following data for each source:

 MMXU.MX.TotW: three-phase active power

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Date: 10 January 2020

 MMXU.MX.TotVAr: three-phase reactive power

 MMXU.MX.VA: three-phase apparent power

 MMXU.MX.TotPF: three-phase power factor

 MMXU.MX.Hz: frequency

 MMXU.MX.PPV.phsAB: phase AB voltage magnitude and angle

 MMXU.MX.PPV.phsBC: phase BC voltage magnitude and angle

 MMXU.MX.PPV.phsCA: Phase CA voltage magnitude and angle

 MMXU.MX.PhV.phsA: phase AG voltage magnitude and angle

 MMXU.MX.PhV.phsB: phase BG voltage magnitude and angle

 MMXU.MX.PhV.phsC: phase CG voltage magnitude and angle

 MMXU.MX.A.phsA: phase A current magnitude and angle

 MMXU.MX.A.phsB: phase B current magnitude and angle

 MMXU.MX.A.phsC: phase C current magnitude and angle

 MMXNx logical nodes provide the following data for each source:

 MMXN.MX.Vol: single-phase voltage magnitude and angle

 MMXN.MX.Hz: single-phase voltage frequency

 MMXN.MX.Amp: single-phase current magnitude and angle

 MSQIx logical nodes provide the following data for each source:

 MSQI.MX.SeqV.c1: positive sequence voltage magnitude and angle

 MSQI.MX.SeqV.c2: negative sequence voltage magnitude and angle

 MSQI.MX.SeqV.c3: zero sequence voltage magnitude and angle

 MSQI.MX.SeqA.c1: positive sequence current magnitude and angle

 MSQI.MX.SeqA.c2: negative sequence current magnitude and angle

 MSQI.MX.SeqA.c3: zero sequence current magnitude and angle

 MSQI.MX.ImbZroV: zero sequence voltage unbalance rate

 MSQI.MX ImbZroA: zero sequence current unbalance rate

 RSYNx logical nodes provide the following data for each source:

 RSYN.MX.DifVClc: voltage difference

 RSYN.MX DifHzClc: frequency difference

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 RSYN.MX DifAngClc: phase angle difference

2.4.3 Protection Logical Nodes

The following list describes the protection elements of this device The specified device will contain

a subset of protection elements from this list

 RBRF: Breaker failure

 RREC: Automatic reclosing

The protection elements listed above contain start (pickup) and operate flags, instead of any element has its own start (pickup) flag separately, all the elements share a common start (pickup) flags “PTRC.ST.Str.general” The operate flag for PTOC1 is “PTOC1.ST.Op.general” These flags take their values from related module for the corresponding element Similar to digital status values, the protection trip information is reported via BRCB, and BRCB also locates in LLN0

2.4.4 LLN0 and Other Logical Nodes

Logical node LLN0 is essential for an IEC 61850 based IED This LN shall be used to address common issues for Logical Devices In this device, most of the public services, the common settings, control values and some device-oriented data objects are available here The public services may be BRCB, URCB and GSE control blocks and similar global defines for the whole device; the common settings include all the setting items of communication settings, system settings and some of the setting items, which can be configured to 2 or more logical nodes In LLN0, the item Loc is a device control object, this Do item indicates the local operation for complete logical device, when it is true, all the remote control commands to the IED will be blocked and those commands make effective until the item Loc is changed to false Besides the logical nodes we describe above, there are some other logical nodes below in the IEDs

 MMXU: This LN shall be used to acquire values from CTs and VTs and calculate measurands such as RMS values for current and voltage or power flows out of the acquired voltage and current samples These values are normally used for operational purposes such as power flow supervision and management, screen displays, state estimation, etc The requested accuracy for these functions has to be provided

 CILO: This LN shall be used to “enable” a switching operation if the interlocking conditions are fulfilled One instance per switching device is needed At least all related switchgear positions have to be subscribed The interlocking algorithm is a local issue

This LN is used for the interlocking function at station level and/or at bay level

Interlocking may be totally centralized or totally decentralized Since the interlocking rules are basically the same on bay and station level and based on all related position indications, the different interlocking LNs may be seen as instances of the same LN class Interlocking (IL)