A Survey of Industry Data Models and Reference Data Libraries
8 Process plant and electrical utility data
A key feature of the process plant and electrical utility data models is the distinction between:
- a system element, which is a role played by a piece of equipment within a system and which can have many different pieces of equipment installed to play the role during its life; and
- a piece of equipment which can be installed as many different system elements during its life.
The industrial data models, described in clause 5.4.4, recognise that the same type of component can be in different places within an assembly design. This is referred to in ISO 10303 as an “occurrence” of a component within a design.
However, the process plant and electrical utility data models go further and recognised during the life of an actual system components can be replaced, and that it is necessary to record the history of these replacements. The history provides two audit trail views:
- for a system element - what equipment has been installed there over time;
- for a piece of equipment - for what system elements has it been installed over time.
Although the engineering requirement is straightforward, different terminologies have been developed to describe it. It has become almost traditional to illustrate the terminologies using the vehicle - wheel example shown in Figure 26.
Figure 26 - Vehicle - wheel example
Comments on Figure 26:
- In this example, a wheel is an “asset” which can be installed for a period of time to play a role within the “system” that is the vehicle.
The terms are prefixed by their source as follows:
- cidt: Core Industrial Data set of Terms (see clause 6.4)
- 15288: ISO/IEC 15288 “System life cycle processes”
- cdd: ISO/IEC Common Data Dictionary (see clause 9.3)
- step: ISO 10303 “Product data representation and exchange” (see clause 6.2)
- qif: Quality Information Framework (see clause 7)
- ccom: MIMOSA CCOM (see clause 8.2)
- cim: EPRI CIM (see clause 8.3)
- 15925: ISO 15926 “Integration of life-cycle data for process plants” (see clause 6.2)
- Neither MIMOSA CCOM nor EPRI CIM are intended as data models for vehicle maintenance, but nonetheless the example serves to illustrate the terminology.
- A vehicle is an assembly as well as a system - many assemblies are both. An electrical transmission system is not usually regarded as an assembly, because the position and orientation of the system elements is largely unimportant. A substation could be regarded as an assembly, but a transformer is certainly an assembly.
8.2 MIMOSA Common Concept Object Model (CCOM)
8.2.1 Defining organization
MIMOSA (formerly Machinery Information Management Open System Alliance) is a trade association that defines open standards for physical asset management.
MIMOSA is involved in the development of ISO 18101 “Automation systems and integration ¾ Oil and gas interoperability” (see https://www.iso.org/standard/68521.html) within ISO TC 184/WG 6. The standard gives guidelines for the collaborative use of different standards. The guidelines have been validated using the Oil and Gas Interoperability (OGI) pilot.
Standards used in the OGI pilot include:
- ANSI/ISA 88 (Batch control) and ANSI/ISA 95 (Enterprise-control system integration)
- MIMOSA CCOM (see clause 8.2)
- OPC Unified Architecture (UA)
- OAGi Business Object Document (BOD) message architecture
- ISO 15926-4 (see clause 8.4)
Only the MIMOSA CCOM and ISO 15926-4 standards are relevant to this report. The other standards are concerned with the data communications and processing.
18.104.22.168 Open O&M
MIMOSA is the host organisation for the Open Operations and Maintenance Initiative, which is concerned with real time and near real time SCADA data. The participating organizations are:
- ISA (International Society of Automation) https://www.isa.org/
- MESA (Manufacturing Enterprise Solutions Association) http://www.mesa.org/
- OAGi (Open Applications Group Inc.) https://oagi.org/
- OPC (Open Platform Communications) Foundation https://opcfoundation.org/
8.2.2 Objectives and scope
The introduction to MIMOSA CCOM says:
MIMOSA CCOM serves as an information model for the exchange of asset information. Its core mission is to facilitate standards-based interoperability between systems: providing an XML model to allow systems to electronically exchange data.
CCOM itself is a single XML schema. Packaged with CCOM are message schemas which support flows of information into and out of a CCOM repository using the OAGi BOD architecture.
8.2.3 Structure of the model
The top level of CCOM is shown in Figure 27.
Figure 27 - MIMOSA CCOM top level
Comments on Figure 27:
- A segment is a part of a process plant that performs a function. In the Core Industrial Data Set of Terms and in ISO/IEC 15288 “System life cycle processes” it is called a “system element”. In ISO 15926-2 it is called a “functional physical object”. In the process industry it is often called a “tagged item”.
- An asset is a moveable material object that can be installed within a process plant as a segment. In the Core Industrial Data Set of Terms it is called a “component”. In ISO 15926-2 it is called a “materialized physical object”.
- An asset segment event is the installation of an asset as a segment. This object is time stamped so that the history of where an asset has been used or of what has been installed as a segment can be obtained from the stored data.
- An asset owner event is similar in structure to an asset segment event. This enables a history of the ownership of an asset to be obtained from the stored data.
The MIMOSA CCOM model is important because it recognises that the system elements within a process plant change over time. Building and geographic data models are largely static.
MIMOSA CCOM is a well-documented XML schema.
8.2.5 Maintenance and usage
MIMOSA-CCOM is actively maintained. The latest revision [in August 2020] was in March 2020.
MIMOSA-CCOM has wide industrial use in operations and maintenance systems.
8.3 EPRI Common Information Model (CIM)
8.3.1 Defining organization
The CIM is maintained by IEC TC 57/WG 13 and published as:
IEC 61970-301 “Energy management system application program interface (EMS-API) - Common information model (CIM) base”;
IEC 61970-301 “Energy management system application program interface (EMS-API) - Common information model (CIM) dynamics”.
The US Electrical Power Research Institute (EPRI) developed the Common Information Model (CIM) as part of its Control Center Application Program Interface (CCAPI) project to provide a common definition for power system components for use in the Energy Management System (EMS) Application Programming Interface (API).
8.3.2 Objectives and scope
The CIM is a large UML model containing more than 600 classes which covers the electrical transmission and distribution domain. Subsets of the CIM called “profiles” are defined for particular applications, which include:
IEC 61970-452 “CIM static transmission network model profiles”;
IEC 61970-453 “Diagram layout profile”;
IEC 61970-456 “Solved power system state profiles”.
A profile is a view on the CIM that specifies exactly how the CIM shall be implemented for a particular application. The CIM is a generic model, which can represent the same information in different ways. The CIM also does not specify which attributes are mandatory, and which are optional.
A profile can then be implemented as a “contextual model”, either in RDF/XML or in XML derived directly from the UML. The approaches are standardised as:
IEC 61970-501 “Common Information Model Resource Description Framework (CIM RDF) schema”;
IEC 61970-552 “CIMXML Model exchange format”.
The CIM as a whole can also be implemented as a SQL database. The Common Information Model Primer published by EPRI (https://www.epri.com/research/products/000000003002006001) contains the following diagram shown as Figure 28.
Figure 28 - CIM implementation architecture
8.3.3. Structure of the model
An extract from the CIM top structure is shown in Figure 29.
Figure 29 - CIM Power system resource and asset
Comments on Figure 29:
- The subclasses of power system resource show the allowed connection and composition relationships and the valid attributes.
- The CIM, like CCOM and ISO 15926, makes a distinction between the functional objects within a system (power system resources) and the assets that are installed as the functional objects. However in CCOM, only asset management information is recorded about an asset, and not its engineering properties. Also the CCOM model does not record the history of asset installations, but merely the asset that is installed “now”.
The EPRI CIM is well documented in UML.
8.3.5 Maintenance and usage
The EPRI-CIM is actively maintained by IEC TC 57. The latest edition of IEC 61970-301 [in August 2020] was published in June 2020.
The EPRI-CIM has wide industrial use transmission and distribution systems.
8.4 ISO 15926 Data model
8.4.1 Defining organization
The ISO 15926 series of standards is maintained by ISO TC 184/SC 4/WG 3.
The initial development of ISO 15926 had involvement from the oil and gas industry, particularly in Norway, the Netherlands and the UK, and from the nuclear industry, particularly in France. Today, there is also involvement from the oil and gas and nuclear industries in Japan, Korea and China.
Initial the standard was intended to be a part of ISO 10303 (STEP), but it became clear that the ISO 10303 architecture did not have the flexibility to support either the large scope or the need to keep a record of changes through time. Therefore ISO 15926 was developed as a companion standard. Both ISO 15926 and ISO 10303 are developed within ISO TC 184/SC 4 “Industrial data”.
8.4.2 Objectives and scope
ISO 15926 was developed to support the storage and sharing of process plant data throughout the life cycle of a process plant, from design, through construction, commissioning, operation and maintenance, to final decommissioning and site clearance.
8.4.3 Structure of the model
The core of the ISO 15926 series of standards is ISO 15926-2 “Data model”. This is a top-level ontology which is described in detail in the Top-Level Ontology Baseline report. The structure of the ISO 15926 data model is similar to that of MIMOSA CCOM, but with a formal inheritance structure. The ISO 15926 equivalent to Figure 27, is Figure 30.
Figure 30 - ISO 15926 top level
Comments on Figure 30:
- The relationship temporal whole part can relate a functional physical object to a materialized physical object that is installed. During the temporal part of a functional physical object during the period of an installation is also a temporal part of the installed materialized physical object.
- The data model does not have subclasses of physical object with explicit relationships and attributes comparable to those in the CIM shown in Figure 29. Instead, this information is provided by reference data libraries.
The ISO 15926-2 data model is published by ISO as a PDF document with EXPRESS-G diagrams, good definitions and examples.
[A pre-standardisation HTML representation was created for review. Currently this is not on the web, which is a problem to be addressed. DL]
8.4.5 Maintenance and usage
The ISO 15926-2 data model is not actively maintained, and has not been revised since published in 2003.
A revision of the data model to comply with ISO/IEC 21838-1 “Information technology — Top-level ontologies (TLO) — Part 1: Requirements” is being discussed.
There have been many industrial systems derived from ISO 15926-2, but little direct implementation of either its EXPRESS schema or of the OWL vocabulary derived from it and standardised as ISO 15926-12.
8.5 ISO 15926 Reference Data Library (RDL)
8.5.1 Defining organization
The ISO 15926 series of standards is maintained by ISO TC 184/SC 4/WG 3.
8.5.2 Objectives and scope
The ISO 15926 “Initial Reference Data Library (RDL)” contains 11,000 classes relevant to process plants. This initial RDL is intended to be extended by company and project specific RDLs.
8.5.3 Structure of the model
The RDL is divided into modules as follows:
- connection material
- encoded information (format type)
- control function
- heat transfer
- information (document type)
- protection material
- rotating equipment
- solid handling
- static equipment
Currently the reference data library is published as spreadsheets, but representation using OWL and SKOS have been derived from this.
8.5.5 Maintenance and usage
The ISO 15926 reference data library is maintained, but progress is very slow. Since its first publication in 2007, the only new edition [in August 2020] was published in November 2019 to update quantity and unit of measure references to ISO 31-1 and ISO 1000 by references to the ISO 80000 series.
The ISO 15926 reference data library is widely used in industry, and there are numerous proprietary extensions.
8.6 Integrated Asset Planning Lifecycle (ILAP)
8.6.1 Defining organization
The ILAP standard was defined by EPIM (E&P Management Association) in Norway. This is now part of Norske Olje & gass.
The standard is published as ISO 15926-13.
8.6.2 Objectives and scope
The Norske Olje & gass website says:
ISO 15926-13:2018 specifies the terminology for asset planning for process plants, including oil and gas production facilities. In addition, it specifies an XML schema for exchange of data used for asset planning.
ILAP interfaces translate the schedules from commercial planning tools to the standard format, readable to other planning tools also equipped with an ILAP interface. By installing the ILAP adapter, the files can be imported and exported to the different tools. The exchange format is based on ISO 15926-13.
At present, ILAP interfaces are available for the following commercial planning tools:
- Microsoft Excel
- MS Project
8.6.3 Structure of the model
ISO 15926 is a framework within which applications for particular process industry activities can be developed. The ILAP standard defines implementation levels, as follows:
this is an extension to the ISO 15926-2 data model for lifecycle asset planning, which is defined by reference data in OWL.
This level corresponds to the ANSI SPARC conceptual level.
This is a view of the extended ISO 15926-2 data model, which is limited to the scope of scheduling applications. The view is defined in OWL. An exchange file is defined by an XML schema, which is automatically derived from the OWL.
This level corresponds to the ANSI SPARC external level with user views.
The relationship between the levels and the generic, conceptual ontology defined in ISO 15926-2 is shown in Figure 31.
Figure 31 - ISO 15926 implementation architecture
Comments on Figure 31:
- ISO/TS 15962-12 is a representation of the ISO 15926-2 data model in OWL Full. This ontology has an OWL-DL subset.
- The “scheduling application view ontology” is a simplification of the ISO 15926-2 data model for the purpose of exchange between scheduling applications. The view is defined in OWL and presented in UML.
- The scheduling application XSD is created by algorithm from the scheduling application view ontology.
The ILAP standard is documented in UML.
8.6.5 Maintenance and usage
A new edition of the ILAP standard is currently [in August 2020] being developed, although a ISO project has not yet begun.
The ILAP standard is used by industry for planning data.
continue to next section: General purpose product dictionaries and classification schemes