AVEVA Measurement Advisor glossary

Balance Object

A database object used to manage summarized Measurement data, typically a balance between inlets and outlets of parts of a pipeline system. The balance levels are:

• Company

• Region

• Subregion

• Line Segment

• Station

Business Object

A database object used to represent business entities. The business objects are:

• Organization

• Contact

Billing Period

A billing period (or statement period) is a bounded period of time (e.g., one month) for which gas billing occurs.

Close Group

A grouping of measuring stations with a common close period (billing period). A close group and a billing group are the same thing.

Company

Several regions grouped together.

Cricondenbar

The maximum pressure at which the hydrocarbon gas will start to condense out of the gaseous phase.

Cricondentherm

The maximum temperature at which the hydrocarbon gas will start to condense out of the gaseous phase.

Critical Point

A point on the Hydrocarbon Dewpoint Curve where the three phases (gas, gas-liquid, and liquid) coexist.

Current Unit Profile

The unit profile currently being used in your display environment.

Data Quality Name

The quality status of the data. This could be one of the following:

• Unassigned

• Missing

• Late

• Late Estimated

• Commissioning

• Valid

• Accepted

• Flagged

• Ignored

Delivery Condition

The delivery conditions of the gas: dry or wet.

Download Deadband

The % change for triggering a gas quality (GQ) download to the field.

Download Time

The time at which a download was initiated.

Note: Download time is only applicable to an external system. (Not to AVEVA Measurement Advisor.)

Edit State

The Edit State provides the current state of the information:

• An Edit State of Observed indicates that the data has been measured in the field. When data is being entered for the first time, you select the Observed checkbox.

• If the Observed checkbox is not selected, the data will be given an Edit State of User Estimated. This means that data from the field is not available. The values that appear should be considered temporary data, to be used only until the real data arrives.

• If Observed Accepted Edit State is applied to a rejected reading, the checks performed to ensure that the data is neither too old or recorded for a date in the future will not occur. Additionally, an Edit State of Observed Accepted allows observed data to be loaded into the system when the data is edited or manually overridden. At this point, a record of the changes will be stored in the Audit History, and the Observed data will be brought into the system.

• Edited indicates that there have been changes to the data. However, this edit state does not account for the values accounted for by the Manual Override state.

• Manual Override indicates that you has overridden fields that are normally calculated, like Volume, Energy,Mass, Specific Gravity, Heating Value Ideal, Specific Gravity Ideal, and Heating Value.

• System Estimate indicates that the data did not exist in the system, so the system provided an estimate.

• Actualized indicates that you has accepted the data. In the event that new telemetered information comes in, the system will not overwrite the Actualized data.

  For more information, refer to About the edit state.

Effective Time

The Effective Time is the time when the object property is effective. Many object properties change with time. Therefore, it is important to know when the new value (of the property) takes effect, and the old value is no longer applicable.

Flow Time

The amount of time that gas was actually flowing through the meter, with a measurement period such as an hour or day. This is used to calculate a volume.

Gas Analysis / Gas Quality

The composition of the gas.

Gauge Pressure

The pressure relative to atmospheric pressure. If the pressure in the pipeline is equal to the atmospheric pressure, the gauge pressure reading is zero.

Granularity

The time resolution of measurements. For example, hourly, daily, monthly, 15-minute interval, irregular or sampled.

Hydrocarbon Dewpoint

The temperature (at a given pressure) at which the hydrocarbon gas, such as natural gas, will start to condense out of the gaseous phase.

In Period Adjustment (IPA)

An edit made to measurement data when that data has not been closed.

Internal Storage Profile

The unit profile in which all data is stored.

Manual Override Options

When the system recalculates the meter readings, you can override the averaging error method.

Note: If you select the manual override and the averaging error method is not None, then the system will reset the value to None and will recalculate.

Mass

The mass is defined as:

Gas:

Mass =Volume × AirDensity × SpecificGravity

Liquid:

Mass =Volume × Density

Note: The mass is calculated whenever the energy is calculated.

Measured Gas Quality (MQ)

The gas composition used by a flow computer in calculating volumetric, energy and/or mass flow, and often uploaded with the flow data.

Measurement Point

A database object used to associate a meter with one or both of a zone GQ and measured GQ.

Measuring Site

Several measuring stations, measurement points, meters and GQs grouped together.

Note: No calculations are performed on a measuring site.

Measuring Station

Several measurement points grouped together.

Meter

A physical field device. For example, an orifice meter or sulphur meter.

Phase Envelope

The phase envelope (hydrocarbon dewpoint curve) displays the hydrocarbon gas pressure versus its temperature. The graph has 3 areas, where the gas can be in a gas state, mixture of gas-liquid state, or a liquid state.

Prior Period Adjustment (PPA)

An adjustment to meter readings that become effective after billing for the meter has originally been approved and submitted. That is, the readings have been closed and then altered.

Pressure Base

The pressure to which a volume of gas is corrected, so that the volume represents a known quantity of gas.

Process State Name

The process status of the data, choices are:

• Wait process

• Consistent

• Inconsistent

• Calculated

• Calculated incomplete.

Run Time

The time that the Remote Terminal Unit (RTU) was recording (running) during a measurement period.

Note: Run Time is applicable to detecting split records.

Sulphur Meter

A meter that measures the volume of sulphur. You enter the mass of sulphur and the system calculates the volume of sulphur.

Telemetry Data

Data that is retrieved from the field.

Temperature Base

The temperature to which a volume is corrected, so that the volume represents a known quantity of gas.

Unit Input Profile

The unit profile that is used to convert the incoming data to the internal storage profile.

Unit Output Profile

The unit profile that is used to convert the data in the internal storage to the desired units for data display or reporting.

Wobbe Index

The Wobbe Index quantifies the interchangeability of gasses better than heating value or specific gravity. It is defined as:

The Wobbe Index is calculated based on the BTU (60) heating value. This is defined as unitless in AVEVA Measurement Advisor and will not have unit conversion applied to it when you change the unit profile.

Zone Quality (ZQ)

Zone Gas Analysis

Zone Gas

Zone Analysis

GQ objects which provide the gas composition for a number of meters within a measurement zone.

Z ratio

When converting a volume from one base conditions to another, the ideal gas law is used (PV = nRT). AVEVA Measurement Advisor gives the option to configure a single alternate set of base conditions that will use the real gas law for the conversion instead (PV = ZnRT). When this is configured, the Z ratio is calculated as the compressibility factor to convert between the specified base conditions and the standard base conditions (14.73 PSI/60ºF). The Z ratio is considered unitless.