VT / PT
Voltage transformer
A transformer providing a voltage signal for metering or protection.
SLD / Schematic
Protection functions · 47
Phase-sequence or voltage-balance protection
Supervises phase order or voltage imbalance using the selected device's voltage inputs.
SLD / Schematic · 47
What it represents
Supervises phase order or voltage imbalance using the selected device's voltage inputs.
In a drafting package, connect this reference to the three-phase voltage measurement circuit. The associated drawing should trace the phase-order or imbalance alarm/trip destination; the number identifies the role and does not specify the terminal arrangement, ratings or operating settings.
How to read it
- Identify the three-phase voltage measurement circuit.
- Trace the phase-order or imbalance alarm/trip destination.
Information to show or reference
- Label the three-phase voltage measurement circuit.
- Cross-reference the phase-order or imbalance alarm/trip destination.
- Identify the device tag, manual revision and logic drawing that define this implementation.
A distinction that matters
Voltage-based supervision 47 differs from current-unbalance function 46.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
ANSI device-number and suffix reference table
Public manufacturer number/name association. Drafting explanations are independently written.
IEEE C37.2-2022: power-system device function numbers
Normative device-number publication; exact edition wording and compliance require the licensed standard.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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