Set of attributes of an asset, representing typical datasheet information of a physical device that can be instantiated and shared in different data exchange contexts:
- as attributes of an asset instance (installed or in stock)
- as attributes of an asset model (product by a manufacturer)
- as attributes of a type asset (generic type of an asset as used in designs/extension planning).
Hash table of SwitchInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ If true, the switch is not ganged (i.e., a switch phase may be operated separately from other phases).
Gas or air pressure at or below which a low pressure alarm is generated.
nan
nan
nan
Rated impulse withstand voltage, also known as BIL (Basic Impulse Level).
nan
If true, it is a single phase switch.
Switch rated interrupting time in seconds.
Time, in seconds
Volume of oil in each tank of bulk oil breaker.
nan
Weight of gas in each tank of SF6 dead tank breaker.
nan
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
The maximum fault current a breaking device can break safely under prescribed conditions of use.
nan
Gas or air pressure below which the breaker will not open.
Same definition as SwitchInfo.lowPressureAlarmFrequency for which switch is rated.
nan
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Hash table of TapChangerInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ Tap changer data.
No Additional PropertiesUsed in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Highest possible tap step position, advance from neutral.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
Built-in current transformer primary rating.
Same definition as SwitchInfo.breakingCapacityBuilt-in voltage transducer ratio.
Rated apparent power.
nan
Tap step increment, in per cent of rated voltage, per step position.
Normally 0 to 100 on a defined base.
Phase shift per step position.
nan
Lowest possible tap step position, retard from neutral.
Voltage at which the winding operates at the neutral tap setting.
Same definition as SwitchInfo.ratedImpulseWithstandVoltageBasic Insulation Level (BIL) expressed as the impulse crest voltage of a nominal wave, typically 1.2 X 50 microsecond. This is a measure of the ability of the insulation to withstand very high voltage surges.
Same definition as SwitchInfo.ratedImpulseWithstandVoltageBuilt-in current transducer ratio.
Whether this tap changer has under load tap changing capabilities.
The neutral tap step position for the winding.
Frequency at which the ratings apply.
Same definition as SwitchInfo.ratedFrequencyThe aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Hash table of WireSpacingInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ Wire spacing data that associates multiple wire positions with the line segment, and allows to calculate line segment impedances. Number of phases can be derived from the number of associated wire positions whose phase is not neutral.
No Additional PropertiesArray of WirePosition objects
No Additional ItemsIdentification, spacing and configuration of the wires of a conductor with respect to a structure.
No Additional PropertiesNumbering for wires on a WireSpacingInfo. Neutrals should be numbered last.
Signed vertical distance from the wire at this position: above ground (positive value) or burial depth below ground (negative value).
nan
Signed horizontal distance from the wire at this position to a common reference point.
Same definition as WirePosition.yCoordUsed in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Number of wire sub-conductors in the symmetrical bundle (typically between 1 and 4).
If true, this spacing data describes a cable.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Distance between wire sub-conductors in a symmetrical bundle.
nan
Usage of the associated wires.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Wire data that can be specified per line segment phase, or for the line segment as a whole in case its phases all have the same wire characteristics.
No Additional PropertiesHash table of OverheadWireInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ Overhead wire data.
No Additional PropertiesArray of WirePhaseInfo objects
No Additional ItemsInformation on a wire carrying a single phase.
No Additional PropertiesPhase information.
Describes the wire gauge or cross section (e.g., 4/0, #2, 336.5).
(if insulated conductor) Thickness of the insulation.
Same definition as WireSpacingInfo.phaseWireSpacing(if used) Number of strands in the steel core.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Current carrying capacity of the wire under stated thermal conditions.
Same definition as SwitchInfo.breakingCapacityOutside radius of the wire.
Same definition as WireSpacingInfo.phaseWireSpacingThe description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
Conductor material.
DC resistance per unit length of the conductor at 20 °C.
nan
AC resistance per unit length of the conductor at 50 °C.
Same definition as WireInfo.rDC20(if there is a different core material) Radius of the central core.
Same definition as WireSpacingInfo.phaseWireSpacing(if insulated conductor) Material used for insulation.
The name is any free human readable and possibly non unique text naming the object.
Number of strands in the conductor.
AC resistance per unit length of the conductor at 75 °C.
Same definition as WireInfo.rDC20AC resistance per unit length of the conductor at 25 °C.
Same definition as WireInfo.rDC20Geometric mean radius. If we replace the conductor by a thin walled tube of radius GMR, then its reactance is identical to the reactance of the actual conductor.
Same definition as WireSpacingInfo.phaseWireSpacingThe aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
True if conductor is insulated.
Hash table of CableInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ Cable data.
Tape shield cable data.
No Additional PropertiesTrue if wire strands are extruded in a way to fill the voids in the cable.
Describes the wire gauge or cross section (e.g., 4/0, #2, 336.5).
(if insulated conductor) Thickness of the insulation.
Same definition as WireSpacingInfo.phaseWireSpacing(if used) Number of strands in the steel core.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Current carrying capacity of the wire under stated thermal conditions.
Same definition as SwitchInfo.breakingCapacityOutside radius of the wire.
Same definition as WireSpacingInfo.phaseWireSpacingThe description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
Kind of outer jacket of this cable.
Maximum nominal design operating temperature.
nan
DC resistance per unit length of the conductor at 20 °C.
Same definition as WireInfo.rDC20Percentage of the tape shield width that overlaps in each wrap, typically 10% to 25%.
Same definition as TapChangerInfo.stepVoltageIncrementDiameter over the core, including any semi-con screen; should be the insulating layer's inside diameter.
Same definition as WireSpacingInfo.phaseWireSpacingAC resistance per unit length of the conductor at 50 °C.
Same definition as WireInfo.rDC20(if there is a different core material) Radius of the central core.
Same definition as WireSpacingInfo.phaseWireSpacing(if insulated conductor) Material used for insulation.
Same definition as WireInfo.insulationMaterialDiameter over the outermost jacketing layer.
Same definition as WireSpacingInfo.phaseWireSpacingThe name is any free human readable and possibly non unique text naming the object.
True if sheath / shield is used as a neutral (i.e., bonded).
Material of the shield.
AC resistance per unit length of the conductor at 75 °C.
Same definition as WireInfo.rDC20Number of strands in the conductor.
Diameter over the insulating layer, excluding outer screen.
Same definition as WireSpacingInfo.phaseWireSpacingKind of construction of this cable.
Thickness of the tape shield, before wrapping.
Same definition as WireSpacingInfo.phaseWireSpacingAC resistance per unit length of the conductor at 25 °C.
Same definition as WireInfo.rDC20Diameter over the outer screen; should be the shield's inside diameter.
Same definition as WireSpacingInfo.phaseWireSpacingGeometric mean radius. If we replace the conductor by a thin walled tube of radius GMR, then its reactance is identical to the reactance of the actual conductor.
Same definition as WireSpacingInfo.phaseWireSpacingThe aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
True if conductor is insulated.
Concentric neutral cable data.
No Additional PropertiesTrue if wire strands are extruded in a way to fill the voids in the cable.
Describes the wire gauge or cross section (e.g., 4/0, #2, 336.5).
(if insulated conductor) Thickness of the insulation.
Same definition as WireSpacingInfo.phaseWireSpacingNumber of concentric neutral strands.
(if used) Number of strands in the steel core.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Current carrying capacity of the wire under stated thermal conditions.
Same definition as SwitchInfo.breakingCapacityOutside radius of the wire.
Same definition as WireSpacingInfo.phaseWireSpacingGeometric mean radius of the neutral strand.
Same definition as WireSpacingInfo.phaseWireSpacingThe description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
Diameter over the concentric neutral strands.
Same definition as WireSpacingInfo.phaseWireSpacingKind of outer jacket of this cable.
Same definition as CableInfo.outerJacketKindMaximum nominal design operating temperature.
Same definition as CableInfo.nominalTemperatureDC resistance per unit length of the conductor at 20 °C.
Same definition as WireInfo.rDC20Diameter over the core, including any semi-con screen; should be the insulating layer's inside diameter.
Same definition as WireSpacingInfo.phaseWireSpacingAC resistance per unit length of the conductor at 50 °C.
Same definition as WireInfo.rDC20(if there is a different core material) Radius of the central core.
Same definition as WireSpacingInfo.phaseWireSpacing(if insulated conductor) Material used for insulation.
Same definition as WireInfo.insulationMaterialOutside radius of the neutral strand.
Same definition as WireSpacingInfo.phaseWireSpacingDiameter over the outermost jacketing layer.
Same definition as WireSpacingInfo.phaseWireSpacingThe name is any free human readable and possibly non unique text naming the object.
True if sheath / shield is used as a neutral (i.e., bonded).
AC resistance per unit length of the conductor at 75 °C.
Same definition as WireInfo.rDC20Number of strands in the conductor.
DC resistance per unit length of the neutral strand at 20 °C.
Same definition as WireInfo.rDC20Diameter over the insulating layer, excluding outer screen.
Same definition as WireSpacingInfo.phaseWireSpacingKind of construction of this cable.
Same definition as CableInfo.constructionKindAC resistance per unit length of the conductor at 25 °C.
Same definition as WireInfo.rDC20Diameter over the outer screen; should be the shield's inside diameter.
Same definition as WireSpacingInfo.phaseWireSpacingGeometric mean radius. If we replace the conductor by a thin walled tube of radius GMR, then its reactance is identical to the reactance of the actual conductor.
Same definition as WireSpacingInfo.phaseWireSpacingThe aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
True if conductor is insulated.
Hash table of PowerTransformerInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ Set of power transformer data, from an equipment library.
No Additional PropertiesArray of TransformerTankInfo objects
No Additional ItemsSet of transformer tank data, from an equipment library.
No Additional PropertiesArray of TransformerEndInfo objects
No Additional ItemsTransformer end data.
No Additional PropertiesArray of NoLoadTest objects
No Additional ItemsNo-load test results determine core admittance parameters. They include exciting current and core loss measurements from applying voltage to one winding. The excitation may be positive sequence or zero sequence. The test may be repeated at different voltages to measure saturation.
No Additional PropertiesTemperature at which the test is conducted.
Same definition as CableInfo.nominalTemperatureExciting current measured from a positive-sequence or single-phase excitation test.
Same definition as TapChangerInfo.stepVoltageIncrementExciting current measured from a zero-sequence open-circuit excitation test.
Same definition as TapChangerInfo.stepVoltageIncrementUsed in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Base power at which the tests are conducted, usually equal to the rateds of one of the involved transformer ends.
Same definition as TapChangerInfo.ratedApparentPowerLosses measured from a positive-sequence or single-phase excitation test.
nan
The name is any free human readable and possibly non unique text naming the object.
Losses measured from a zero-sequence excitation test.
Same definition as NoLoadTest.lossThe description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
Voltage applied to the winding (end) during test.
Same definition as SwitchInfo.ratedImpulseWithstandVoltageArray of ShortCircuitTest objects
No Additional ItemsShort-circuit test results determine mesh impedance parameters. They include load losses and leakage impedances. For three-phase windings, the excitation can be a positive sequence (the default) or a zero sequence. There shall be at least one grounded winding.
No Additional PropertiesTemperature at which the test is conducted.
Same definition as CableInfo.nominalTemperatureShort circuit apparent power.
Same definition as TapChangerInfo.ratedApparentPowerLeakage impedance measured from a positive-sequence or single-phase short-circuit test.
nan
Leakage impedance measured from a zero-sequence short-circuit test.
Same definition as ShortCircuitTest.leakageImpedanceLoad losses from a positive-sequence or single-phase short-circuit test.
Same definition as NoLoadTest.lossTap step number for the energised end of the test pair.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Base power at which the tests are conducted, usually equal to the rateds of one of the involved transformer ends.
Same definition as TapChangerInfo.ratedApparentPowerShort circuit voltage..
Same definition as TapChangerInfo.stepVoltageIncrementTap step number for the grounded end of the test pair.
Load losses from a zero-sequence short-circuit test.
Same definition as NoLoadTest.lossThe description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Apparent power that the winding can carry under emergency conditions (also called long-term emergency power).
Same definition as TapChangerInfo.ratedApparentPowerWinding phase angle where 360 degrees are represented with clock hours, so the valid values are {0, ..., 11}. For example, to express the second winding in code 'Dyn11', set attributes as follows: 'endNumber'=2, 'connectionKind' = Yn and 'phaseAngleClock' = 11.
Rated voltage: phase-phase for three-phase windings, and either phase-phase or phase-neutral for single-phase windings.
Same definition as SwitchInfo.ratedImpulseWithstandVoltageBasic insulation level voltage rating.
Same definition as SwitchInfo.ratedImpulseWithstandVoltageKind of connection.
DC resistance.
nan
Normal apparent power rating.
Same definition as TapChangerInfo.ratedApparentPowerUsed in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
Apparent power that this winding can carry for a short period of time (in emergency).
Same definition as TapChangerInfo.ratedApparentPowerNumber for this transformer end, corresponding to the end's order in the PowerTransformer.vectorGroup attribute. Highest voltage winding should be 1.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.
Hash table of ShuntCompensatorInfo objects
No Additional PropertiesAll properties whose name matches the following regular expression must respect the following conditions
Property name regular expression:^.+$ Properties of shunt capacitor, shunt reactor or switchable bank of shunt capacitor or reactor assets.
No Additional PropertiesMaximum allowed apparent power loss.
Same definition as TapChangerInfo.ratedApparentPowerRated reactive power.
nan
Used in RAVENS Schema to identify the corresponding CIM Object Type of the JSON object.
The description is a free human readable text describing or naming the object. It may be non unique and may not correlate to a naming hierarchy.
The aliasName is free text human readable name of the object alternative to IdentifiedObject.name. It may be non unique and may not correlate to a naming hierarchy.
The attribute aliasName is retained because of backwards compatibility between CIM relases. It is however recommended to replace aliasName with the Name class as aliasName is planned for retirement at a future time.
Master resource identifier issued by a model authority. The mRID is unique within an exchange context. Global uniqueness is easily achieved by using a UUID, as specified in RFC 4122, for the mRID. The use of UUID is strongly recommended.
For CIMXML data files in RDF syntax conforming to IEC 61970-552, the mRID is mapped to rdf:ID or rdf:about attributes that identify CIM object elements.
The name is any free human readable and possibly non unique text naming the object.