MeasurementType

description

This document describes the MeasurementType as part of the modelling-guidelines for the NBNL Profile Group.
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current
author

Arend Hagreis, ahagreis@netbeheernederland.nl
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Issue on GitHub (Netbeheer-Nederland/modeling-guidelines)

Introduction

This document is part of the grid modelling approach and details the grid model data requirements for data supplied by Dutch transmission and distribution system operators and describes in detail the Measurement Type attribute.

Most of the terms in this document are used within the energy industry, particularly in standards like the IEC Common Information Model (CIM).

Description

The MeasurementType class represents the type of measurement being taken. It is used to categorize and identify different types of measurements in a standardized way.

For the NBNL Operation profile, the MeasurementType is extended with a MeasurementKind enumeration to further categorize measurements based on their purpose or context.

Attributes

measurementType: A string attribute that specifies the type of measurement. This could include values such as "voltage", "current", "power", etc.

Modelling choices

  • The MeasurementType class is designed to be flexible and extensible, allowing for the addition of new measurement types as needed.

  • The MeasurementType attribute is a string to allow for a wide range of measurement types without being limited to a predefined set of values. However, it is recommended to use standardized measurement types where possible to ensure consistency across different datasets and systems, see table 1.

  • It shall be noted that table 1 is not an exhaustive list and is intended to provide guidance on the types of measurements that are commonly used in power system modelling and analysis.

  • Measurement.Terminal shall reference a Terminal of the Equipment referenced by Measurement.PowerSystemResource except in cases where Measurement.measurementType is either "TapPosition" or "SwitchPosition" in which the association is not exchanged. See also Measurement and Measurement Values.

  • The MeasurementType can be used in conjunction with other classes such as Measurement and MeterReading to provide a comprehensive representation of measurement data in power system models. For the use in the Operations profile, see table 2 where the valid measurement types for each of the subtypes of Measurement (Analog, Accumulator, Discrete) are defined and some extra attributes such as unitSymbol and description are added.

  • The MeasurementType is extended in the NBNL Operation profile with a nl:MeasurementKind enumeration. This attribute can be used to further categorize measurements based on their purpose or context, such as "piekbelasting" (peak load), see the use MeasurementKind for NBNL Operations profile section below.

Measurement Types

This Table describes various types of measurements based on the IEC 61970, the meanings of the columns are as follows:

  • measurementType (Measurement.measurementType) is the measurement type name.

  • description is the description.

Table 1. Measurement Types
measurementType description

Current

Current (rms) of a non-three phase circuit

ThreePhaseCurrent

Total current (rms) in a three phase circuit

PhaseCurrent

Measured phase current.

Frequency

Frequency

PowerFactor

Power factor not allocated to a phase

ThreePhasePowerFactor

Average power factor in a three phase circuit

ThreePhaseApparentPower

Total apparent power in a three phase circuit

ThreePhaseReactivePower

Total reactive power in a three phase circuit

ThreePhaseActivePower

Total real power in a three phase circuit.

ApparentPower

Apparent power in a non-three phase circuit

ReactivePower

Reactive power in a non-three phase circuit

Voltage

Voltage (rms) not allocated to a phase

ActivePower

Real power in a non-three phase circuit

Pressure

Pressure

Temperature

Temperature

Angle

Angle between voltage and current

ApparentEnergy

Apparent energy

ReactiveEnergy

Reactive energy

ActiveEnergy

Real energy

Automatic

Automatic operation (not manual)

LocalOperation

Local operation (not remote)

SwitchPosition

Switch position [2bits= intermediate,open,closed,ignore]

TapPosition

Position of power transformer Tap or phaseshifter

OperationCount

Operation count – typically for switches

LineToNeutralVoltage

Line to neutral voltage.

LineToGroundVoltage

Line to ground voltage.

Measurement Types for Operations profile

Shortlist of measurement types for the Operations profile that are valid for each of the subtypes of Measurement (Analog, Accumulator, Discrete) is defined in Table 2.

The meanings of the columns are as follows:

  • Measurement Subclass is the subclass of Measurement (Analog, Accumulator, Discrete).

  • MeasurementType (Measurement.measurementType) is the measurement type name.

  • UnitSymbol is the unit symbol for the measurement type, for example W for power, etc.

  • Description is the description.

Table 2. Operations measurementtypes
Measurement Subclass MeasurementType UnitSymbol Description

Analog

ThreePhaseActivePower (\(P\))

W

Active power of the load. Load sign convention is used, i.e. positive sign means flow out from a node.

In a symmetrical three-phase AC network, to calculate real (active) power, multiply by the power factor (\(\cos\phi\)): \(P = \sqrt{3} \cdot U \cdot I \cdot \cos\phi\).

ThreePhaseApparantPower (\(S\))

VA

Apparent power of the load. Load sign convention is used, i.e. positive sign means flow out from a node.

In a symmetrical three-phase AC network, the correct formula for calculating the total apparent power (\(S\)) using the line-to-line voltage (\(U_{L}\)) and line current (\(I_{L}\)) is:\(S=\sqrt{3}\cdot U\cdot I\)

ThreePhaseReactivePower (\(Q\))

VAr

Reactive power of the load. Load sign convention is used, i.e. positive sign means flow out from a node.

LineCurrent (\(I_{L}\))

A

LineCurrent, The symbol A is used in case of three phase AC networks if the three currents are equal or nearly equal.

PhaseVoltage (\(U_{ph}\))

V

PhaseVoltage, line-to-earth voltage, line-to-neutral voltage (in a three-phase AC systems with a neutral conductor (low-voltage networks))

Voltage (\(U\))/ LineToLineVoltage (\(U_{L}\))

V

Voltage / LineToLineVoltage, V is the general symbol, with no further indication: line-to-line voltage; line-to-line tension (IEC 60027-7)

Angle

deg

Frequency

Hz

TapPosition

none

Accumulator

ApparentEnergy

VAh

ReactiveEnergy

VArh

ActiveEnergy

Wh

Discrete

SwitchPosition

none

The use of MeasurementKind for NBNL Operations profile

The cim:MeasurementType is extended with the nl:MeasurementKind enumeration in the NBNL Operation profile to provide additional context and categorization for Measurements. This allows for more specific identification of the type of measurement being taken. The MeasurementKind enumeration includes specific values that are relevant to the operations of the power system, such as "piekbelasting" (peak load) and "Benodigde TransportCapaciteit" (required transport capacity), among others.

To extend the MeasurementType with a MeasurementKind enumeration in the NBNL Operation profile, you can define the MeasurementKind attribute as follows:

For Example:

"cim:Measurement.measurementType": {
  "@id": "nl:MeasurementKind.piekbelasting"}

see also nl:MeasurementKind enumeration for the list of valid values for MeasurementKind in the NBNL Operation profile.