Three-Phase Meter

Description of the Three-phase Meter component, which measures currents and voltages of a three-phase system.

The three-phase meter is a component is located in the Microgrid Library. The component's icon and properties window are shown in Table 1. The three-phase meter measures currents and voltages of three-phase system. It outputs the measured values through signal processing output. The output is a fixed size vectorized output. Within the properties window of the meter, different measurements can be enabled/disabled. It is recommended to enable only the measurements that are really required in order to save computational resources. Outputs that are not selected will be automatically set to zero.

Table 1. Three-Phase Meter in the Schematic Editor core library
component component dialog window component parameters

Three-Phase Meter
  • Property tabs:
    • General
    • Voltage
    • Current
    • Frequency
    • Voltage RMS
    • Current RMS
    • Power
Figure 1. Three-phase meter component view under its mask.

Tab: "General"

In this tab, the snubber resistance, number of cycles to average on RMS calculations and execution rate can be set. It is also possible to enable internal probes, enable output port, remove the snubbers and enable/set bandwidth.

Figure 2. General properties tab
Parameter Code name Description
Snubber resistance R Snubber resistance value. Snubber resistors are connected in parallel to the phase voltage measurements. [Ω]
Number of cycles to average on RMS calculation n_cycles Number of cycles to use when calculating RMS. This results in an RMS measurement average over "n_cycles". [Integer]
Execution rate Ts Execution rate of the inner signal processing components. [s]
Enable internal probes enable_probes Checkbox that enables the placement of probes for the enabled measurements. Set as True by default.
Enable output port enable_out Checkbox that enables the regular output port. Set as True by default.
Remove snubbers remove_snubber Checkbox that removes the resistive snubbers from the meter circuit. When set to True, the property Snubber resistance is disabled. Set as False by default.

WARNING: When this property is set to True, the user must connect the ground port to a valid reference, otherwise measurements will be compromised.
Enable bandwidth enable_bandwidth Checkbox that enables the bandwidth setting for instantaneous voltage and current measurements.. When set to True, the property Bandwidth is shown and enabled. Set as False by default.
Bandwidth bandwidth Bandwidth of the low pass filter of the instantaneous voltage and current measurements. This property is hidden by default. [Hz]

Tab: "Voltage"

In this properties tab, the phase, line and neutral instantaneous voltage measurements can be enabled.

Figure 3. Voltage properties tab
Parameter Code name Description
Phase voltage measurement (A) VAn Checkbox that enables the measurement of phase A's instantaneous voltage
Phase voltage measurement (B) VBn Checkbox that enables the measurement of phase B's instantaneous voltage
Phase voltage measurement (C) VCn Checkbox that enables the measurement of phase C's instantaneous voltage
Line voltage measurement (AB) VAB Checkbox that enables the measurement of A-B line's instantaneous voltage
Line voltage measurement (BC) VBC Checkbox that enables the measurement of B-C line's instantaneous voltage
Line voltage measurement (CA) VCA Checkbox that enables the measurement of C-A line's instantaneous voltage
Estimated neutral voltage measurement (N) VN Checkbox that enables the instantaneous neutral voltage estimation by summing the line-to-neutral three-phase voltages.

Tab: "Current"

In this properties tab, the phase and neutral instantaneous current measurements can be enabled.

Figure 4. Current properties tab
Parameter Code name Description
Phase current measurement (A) IA Checkbox that enables the measurement of phase A's instantaneous current
Phase current measurement (B) IB Checkbox that enables the measurement of phase B's instantaneous current
Phase current measurement (C) IC Checkbox that enables the measurement of phase C's instantaneous current
Estimated neutral current measurement (N) IN Checkbox that enables the instantaneous neutral current estimation by summing the three-phase currents.

Tab: "Frequency"

In this property tab, the frequency measurement can be enabled. The frequency is measured using a PLL block.

Figure 5. Frequency properties tab
Parameter Code name Description
Frequency measurement freq Checkbox that enables the frequency measurement using a three-phase PLL component

Tab: "Voltage RMS"

In this properties tab, the phase, line and neutral RMS voltage measurements can be enabled.

Figure 6. Voltage RMS properties tab
Parameter Code name Description
Phase voltage measurements (VAn, VBn, VCn) VLn_rms Checkbox that enables the RMS measurements of the three-phase phase voltages (VAn, VBn and VCn).
Line voltage measurement (VAB, VBC, VCA) VLL_rms Checkbox that enables the RMS measurements of the three-phase line voltages (VAB, VBC and VCA)
Average phase voltage RMS measurement (VLn) VLn_avg_rms Checkbox that enables the average RMS measurement of the three-phase phase voltages.
Average line voltage RMS measurement (VLL) VLL_avg_rms Checkbox that enables the average RMS measurement of the three-phase line voltages.
Estimated neutral voltage RMS measurement (VN) VN_rms Checkbox that enables the RMS measurement of the estimated neutral voltage.

Tab: "Current RMS"

In this properties tab, the phase and neutral RMS current measurements can be enabled.

Figure 7. Current RMS properties tab
Parameter Code name Description
Phase current RMS measurements (IA, IB, IC) I_rms Checkbox that enables the RMS measurement of the three-phase phase currents (IA, IB, and IC)
Average phase current RMS measurement (I) I_avg_rms Checkbox that enables the average RMS measurement of the three-phase phase currents.
Estimated neutral current RMS measurement (IN) IN_rms Checkbox that enables the RMS measurement of the estimated neutral current.

Tab: "Power"

In this properties tab, the power method can be selected, and the power measurement and the extra output port can be enabled.

Figure 8. Power properties tab
Parameter Code name Description
Power measurement method P_method
Combo box that enables the selection between two different power measurement methods.
  • alpha-beta: uses the alpha-beta transformation for power calculation.
  • RMS based: uses RMS measurements to calculate power. Enables per-phase power calculation.
Enable extra output port enable_extra_out Checkbox that enables an extra output port.

This checkbox is only enabled when the Power measurement method is set to RMS based. The extra output port only contains per-phase power information.
Power measurement P_meas Checkbox that enables the power measurement according to the Power measurement method chosen.

Example

Overall behavior can be better understood with the use of the given three-phase meter example:

Model name: meter_and_const_z_load.tse

SCADA interface: SCADA_Panel.cus

Path: /examples/models/microgrid/meter_and_constant_z_load/