61970-301©1EC:2003 -15- This information is used by Load Forecasting and Load Management. 4.2.8 Generation The Generation package is divided into two subpackages:Production and GenerationDynamics. 4.2.8.1 Production This package provides models for various kinds of generators.It also models production costing information which is used to economically allocate demand among committed units and calculate reserve quantities. This information is used by Unit Commitment and Economic Dispatch of Hydro and Thermal Generating Units,Load Forecasting.and Automatic Generation Control applications. 4.2.8.2 Generation Dynamics This package provides models for prime movers,such as turbines and boilers,which are needed for simulation and educational purposes This information is used by the Unit Modeling for Dynamic Training Simulator applications 4.2.9 Domain The Domain package is a data dictionary of quantities and units that define datatypes for attributes(properties)that may be used by any class in any other package. This package contains the definition of primitive datatypes,including units of measure and permissible values.Each datatype contains a value attribute and an optional unit of measure, which is specified as a static variable initialized to the textual description of the unit of measure Permissible values for enumerations are listed in the documentation for the attribute using UML constraint syntax inside curly braces.String lengths are listed in the documentation and are also specified as a length property. 4.3 CIM Classes and Relationships The class diagram(s)for each CIM package shows all the classes in the package and their relationships.Where relationships exist with classes in other packages,those classes are also shown with a note identifying the package which owns the class. Classes and objects model what is in a power system that needs to be represented in a common way to EMS applications.A class is a description of an object found in the real world,such as a power transformer,generator,or load that needs to be represented as part of the overall power system model in an EMS.Other types of objects include things such as schedules and measurements that EMS applications also need to process,analyze,and store.Such objects need a common representation to achieve the purposes of the EMS-API standard for plug- compatability and interoperability.A particular object in a power system with a unique identity is modeled as an instance of the class to which it belongs. It should also be noted that the CIM is defined to facilitate data exchange.As defined in this document,CIM entities have no behavior other than default create,delete,update and read.In order to make the CIM as generic as possible it is highly desirable to make it easy to configure for specific implementations.In general it is easier to change the value or domain of an attribute than to change a class definition.These principles imply that the CIM should avoid defining too many specific sub-types of classes.Instead the CIM defines generic classes with attributes giving the61970-301  IEC:2003 – 15 – This information is used by Load Forecasting and Load Management. 4.2.8 Generation The Generation package is divided into two subpackages: Production and GenerationDynamics. 4.2.8.1 Production This package provides models for various kinds of generators. It also models production costing information which is used to economically allocate demand among committed units and calculate reserve quantities. This information is used by Unit Commitment and Economic Dispatch of Hydro and Thermal Generating Units, Load Forecasting, and Automatic Generation Control applications. 4.2.8.2 Generation Dynamics This package provides models for prime movers, such as turbines and boilers, which are needed for simulation and educational purposes. This information is used by the Unit Modeling for Dynamic Training Simulator applications. 4.2.9 Domain The Domain package is a data dictionary of quantities and units that define datatypes for attributes (properties) that may be used by any class in any other package. This package contains the definition of primitive datatypes, including units of measure and permissible values. Each datatype contains a value attribute and an optional unit of measure, which is specified as a static variable initialized to the textual description of the unit of measure. Permissible values for enumerations are listed in the documentation for the attribute using UML constraint syntax inside curly braces. String lengths are listed in the documentation and are also specified as a length property. 4.3 CIM Classes and Relationships The class diagram(s) for each CIM package shows all the classes in the package and their relationships. Where relationships exist with classes in other packages, those classes are also shown with a note identifying the package which owns the class. Classes and objects model what is in a power system that needs to be represented in a common way to EMS applications. A class is a description of an object found in the real world, such as a power transformer, generator, or load that needs to be represented as part of the overall power system model in an EMS. Other types of objects include things such as schedules and measurements that EMS applications also need to process, analyze, and store. Such objects need a common representation to achieve the purposes of the EMS-API standard for plug- compatability and interoperability. A particular object in a power system with a unique identity is modeled as an instance of the class to which it belongs. It should also be noted that the CIM is defined to facilitate data exchange. As defined in this document, CIM entities have no behavior other than default create, delete, update and read. In order to make the CIM as generic as possible it is highly desirable to make it easy to configure for specific implementations. In general it is easier to change the value or domain of an attribute than to change a class definition. These principles imply that the CIM should avoid defining too many specific sub-types of classes. Instead the CIM defines generic classes with attributes giving the