Flicker Module
The Flicker Module measures flicker disturbances as defined in IEC Standard 61000-4-15.
Module icon
Overview
A flicker disturbance is a repetitive low-frequency modulation of system voltage; these disturbances are usually caused by a large fluctuating load somewhere within the power system. Lighting systems typically "flicker" when such disturbances occur. A user-defined model of a typical lighting system is selected, and then the module evaluates short-term (Pst) and long-term (Plt) flicker severity.
NOTE: The registers and settings available in this module depend on the device or node you are configuring, as well as its firmware and template versions. Not all registers or settings are available on all devices or the Virtual Processor, and labels may vary.
Inputs
V1, V2, V3
These inputs are linked to the Vln a, Vln b, and Vln c outputs respectively of the HS Power Meter Module, and cannot be changed.
V1 Delta, V2 Delta, V3 Delta
These inputs are linked to the Vll ab, Vll bc, and Vll ca outputs respectively of the HS Power Meter Module, and cannot be changed.
VoltsMode
This input is linked to the Volts Mode setup register of the Power Meter Module, and cannot be changed. The Flicker module behaves differently depending on what Volts Mode setting your meter has. Refer to “Detailed Module Operation” for details.
NomFreq
This input is linked to the NomFreq setup register of the Factory Module, and cannot be changed. This input can be used to define which lamp type is being modeled by the Flicker module; refer to the Lamp Type setup register description below.
Enable
This input enables or disables the Flicker Module. Disabling the module sets all the module’s outputs to N/A (not available). When the module is re-enabled, the flicker calculations are re-initialized, and the outputs remain N/A until the next full Pst Period expires. The Plt outputs also remain as N/A until the next full Plt Period expires. The module will not respond to any inputs other than Enable or Reset while Enable is false. This input is optional; if you leave it unlinked, the module is enabled by default.
Reset
This input discards all the data collected for the pending flicker calculations and sets the Flicker Module's Pst and Plt output registers to N/A (not available). The Pst output registers remain N/A until the next full Pst Period expires; similarly, the Plt outputs will remain as N/A until the next full Plt Period expires. This input is optional.
Setup registers
Pst Period
This register defines the number of seconds between successive Pst Update, Phase 1 Pst, Phase 2 Pst, and Phase 3 Pst output register updates.
Plt Period
This register defines the number of seconds between successive Plt Update, Phase 1 Plt, Phase 2 Plt, and Phase 3 Plt output register updates. Plt Period must be an integer multiple of the Pst Period.
Lamp Type
This register defines the type of lamp the Flicker module emulates when it calculates flicker severity. The list of available Lamp Type settings contains lamps that comply with IEC Standards and/or Draft IEEE adoptions. Another available setting for Lamp Type includes automatic; when automatic is selected, the NomFreq input is used to define the characteristics of the emulated Lamp Type. Details on each setting are described in “Detailed Module Operation”.
Volts Method
This register determines the input values used by the Flicker module. When V L-L is selected, the module uses the V1 Delta, V2 Delta and V3 Delta inputs to calculate flicker. In automatic, the module uses either the V1, V2 and V3 inputs, or the V1 Delta, V2 Delta and V3 Delta inputs for its calculations, based on the Volts Mode setting in the Power Meter module. This allows the meter to be used in Wye configuration, but evaluate flicker on L-L voltage.
NOTE: Volts MethodV L-L is only available when the meter's Volts Mode is set to 4-wire Wye.
Output registers
Phase 1 Pst, Phase 2 Pst, Phase 3
Pst
These three outputs provide short-term flicker severity over the last Pst Period for Phase 1, Phase 2, and Phase 3 respectively. Note that the definition for each Phase depends on your meter's Volts Mode setting (refer to “Detailed Module Operation”).
Seconds Until Pst Update
The number of seconds remaining until the Flicker module will produce a new evaluation of Pst for all valid phases.
Pst Update
This output register will be pulsed when new Pst values are generated on the Phase 1 Pst, Phase 2 Pst, and/or Phase 3 Pst outputs.
Phase 1 Plt, Phase 2 Plt, Phase 3
Plt
These three outputs provide long-term flicker severity over the last Plt Period for Phase 1, Phase 2, and Phase 3 respectively. Note that the definition for each Phase depends on your meter's Volts Mode setting (refer to “Detailed Module Operation”).
Seconds Until Plt Update
The number of seconds remaining until the Flicker module will produce a new evaluation of Plt for all valid phases.
Plt Update
This output register will be pulsed when new Plt values are generated on the Phase 1 Plt, Phase 2 Plt, and/or Phase 3 Plt outputs.
Event
Any events produced by the Flicker module are recorded in the Event register.
Possible events and their associated priority numbers are shown in the following table:
| Event priority group | Priority | Description |
|---|---|---|
| Setup Change | 10 | Input links, setup registers or labels have changed. |
The Event output register stores the following information for each ION event: time stamp, priority, cause, effect, and any values or conditions associated with the cause and effect.
Detailed module operation
The Flicker module uses line-to-neutral or line-to-line voltage waveform data to provide flicker calculations based on a user-defined lamp type. The module outputs both short-term and long-term flicker severity for up to three phases (the phases are dependent on the Volts Mode setting of your meter; see below). These outputs are predictions of the level of flicker which would be perceived by an observer of a lighting system which is affected by the voltage disturbances.
The short-term evaluation of flicker (Pst), usually evaluated over 10 minutes, is an indication of the perceived short-term severity of the flicker. Pst values of 1.0 are commonly accepted as the “threshold of irritability” of a flickering lamp — if Pst is less than 1.0, the flickering of a lamp is not likely to be irritating. The Flicker module collects its Pst results over a longer period (typically 2 hours), and uses this data to calculate a Plt value. Plt values greater than 0.65 indicate that the flickering lamp is likely to be irritating.
Lamp types
Flicker severity is a function of the lighting system used — the Flicker module's Lamp Type setup register provides a number of accepted lamp types which are used in an IEC-style flicker measurement system.
This setup register also contains an automatic setting: the module uses lamps based on the nominal frequency of the power system you are measuring from. Your ION device may contain the following settings for Lamp Type:
| Setting | Description |
|---|---|
| 230V-50Hz-60W Incandescent | The Flicker module will model a 230V, 60W incandescent light bulb for a system voltage frequency of 50Hz. If this setting is used for a 60Hz system, your Pst and Plt evaluations will be erroneous. |
| 120V-50Hz-60W Incandescent | The Flicker module will model a 120V, 60W incandescent light bulb for a system voltage frequency of 50Hz. If this setting is used for a 60Hz system, your Pst and Plt evaluations will be erroneous. |
| 230V-60Hz-60W Incandescent | The Flicker module will model a 230V, 60W incandescent light bulb for a system voltage frequency of 60Hz. If this setting is used for a 50Hz system, your Pst and Plt evaluations will be erroneous. |
| 120V-60Hz-60W Incandescent | The Flicker module will model a 120V, 60W incandescent light bulb for a system voltage frequency of 60Hz. If this setting is used for a 50Hz system, your Pst and Plt evaluations will be erroneous. |
| Automatic | The Flicker module will determine which lamp type to model based on its NomFreq input as follows: if NomFreq is 50Hz, then the Flicker module will model a 230V, 60W incandescent lamp, as described by IEC Standard 61000-4-15. If NomFreq is 60Hz, then the Flicker module will model a 120V, 60W incandescent lamp, as described in the Draft IEEE adoption of the IEC standard for 120V systems. |
Volts Mode and Volts Method
The Flicker module's VoltsMode and Volts Method determine whether line-to-neutral or line-to-line waveforms are analyzed for flicker.
| VoltsMode register setting | Inputs used | Flicker module outputs |
|---|---|---|
| 4W-Wye or 9S - 4 Wire Wye/Delta | V1, V2, V3 | All outputs available |
3W-Wye or 29S - 4 Wire Wye or 36S - 4 Wire Wye | V1, V3 | Phase 2 Pst and Phase 2 Plt are not available |
| Delta or 35S - 3 Wire | V1 Delta, V2 Delta, V3 Delta | All outputs available |
| Single | V1, V2 | Phase 3 Pst and Phase 3 Plt are not available |
| Demo | N/A | All outputs are N/A |