IEC61850 ISO/OSI Model

IEC 61850 is the most recent standard for communication networks and systems in substations. Its scope of definitions greatly exceeds that of the preceding standard IEC 60870-5-101. IEC 61850 comprises the these individual standards:

• IEC 61850-1, 61850-2
  Introduction and overview / Glossary
• IEC 61850-3
  General requirements
• IEC 61850-4
  System and project management
• IEC 61850-5
  Communication 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) - Mapping 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

IEC 61850 is not limited to the transmission format, but also defines a complete data model. It also introduces an XML-based language (Substation Configuration description Language -? SCL) offering a vendor-independent method of describing devices and their configurations.

ISO/OSI Model

7	Application Layer	TimeSync SNTP	SV Sampled Values	GOOSE Generic Object Oriented Substation Event	GSSE Generic Substation Status Event MMS ISO 9506	MMS ISO 9506 Core ACSI Services
6	Presentation Layer	n/a	n/a	ASN.1, BER (Basic Encoding Rules) ISO/IEC 8824.1
5	Session Layer	n/a	n/a	n/a	Connectionless session ISO/IEC 9548	Connection oriented session ISO/IEC 8327
4	Transport Layer	UDP/IP	n/a	n/a	GSSE T-Profile ISO/IEC 8602	ISO CO T-Profile ISO/IEC 8073	TCP/IP T-Profile ISO Transport on top of TCP (RFC 1006)
3	Network Layer	IP (RFC 791)	n/a	n/a	ISO/IEC 9542	ISO/IEC 8473	IP (RFC 791)
2	Link Layer	RFC 894	Priority Tagging/VLAN (IEEE 802.1Q) CSMA/CD (ISO/IEC 8802.3)		ISO/IEC 8802-2 LLC		RFC 894
1	Physical Layer	ISO/IEC 8802.3 Ethertype			ISO/IEC 8802.3		ISO/IEC 8802.3 Ethertype

注：

OSI/ISO
国际标准化组织/开放系统互连

计算机网络体系结构是指通过系统的整体设计，为网络硬件，软件、协议，存取控制和拓扑提供标准。网络体系结构广泛采用的是国际标准化组织（ISO）在1979年提出的开放系统互连（OSI）的参考模型。该模型用七个功能层次描述网络的结构：

层次	功能
应用层	提供各种网络服务，如文件传输，虚拟终端，电子邮件等
表示层	数据表示和字符编码转换
会话层	对话管理，包括通讯的建立和拆除
传输层	端到端的数据发送
网络层	确定分组从源端到目的端的路径选择
数据链路层	任务是把物理层传输比特的功能加强，使之为网络层显现一条无措线路
物理层	涉及原始数据在通讯道上的传输