24kV Voltage Transformer (Outdoor type)

24kV Voltage Transformer

24kV Outdoor Voltage Transformer (VT), also known as an Outdoor Potential Transformer (PT), is an instrument transformer designed to accurately step down medium-voltage system voltages up to 24 kV into standardized low-voltage outputs for metering, protection, monitoring, and control. It is engineered for outdoor service with weather-resistant insulation and housing, ensuring reliable operation in demanding environmental conditions.

Main Functions
·Voltage Measurement: Converts medium-voltage levels to standardized secondary voltages (typically 100 V or 110 V) for metering and monitoring.
·Protection: Provides precise voltage signals to protective relays for overvoltage, undervoltage, directional, synchronization, frequency, and distance protection.
·Electrical Isolation: Electrically isolates high-voltage circuits from low-voltage metering and protection equipment, improving operational safety.

Typical Applications
·Outdoor distribution substations
·Utility power distribution networks
·Pole-mounted distribution systems
·Renewable energy plants (solar and wind)
·Industrial switchyards
·Commercial power distribution systems
·Mining, oil & gas, and petrochemical facilities

Typical Technical Specifications
·Rated Voltage: 24 kV
·Highest System Voltage: 24 kV or 25.8 kV
·Rated Frequency: 50 Hz / 60 Hz
·Rated Primary Voltage: 22 kV, 24 kV, or 22/√3 kV
·Rated Secondary Voltage: 100 V, 110 V, 100/√3 V, 110/√3 V
·Accuracy Class: 0.1, 0.2, 0.5, 1.0, 3P, 6P
·Rated Burden: 10 VA, 15 VA, 30 VA, 50 VA, 100 VA
·Insulation Medium: Epoxy resin or porcelain housing
·Creepage Distance: According to pollution class requirements
·Cooling Method: Natural Air (AN)
·Installation: Outdoor

Construction
A typical 24kV outdoor voltage transformer consists of:
·High-voltage primary winding
·One or more secondary windings
·Laminated silicon steel magnetic core
·Epoxy resin encapsulation or porcelain insulator housing
·Weather-resistant external insulation
·Primary terminals
·Sealed secondary terminal box
·Mounting base
·Earthing terminal

The outdoor construction is designed to withstand:
·Rain and humidity
·UV radiation
·Dust and airborne contaminants
·Salt fog in coastal environments
·Wide ambient temperature variations

Common Types
·Single-phase inductive voltage transformer
·Phase-to-ground voltage transformer
·Phase-to-phase voltage transformer
·Dual-secondary voltage transformer for metering and protection
·Fuse-protected voltage transformer
·Pole-mounted voltage transformer

Advantages
·High measurement accuracy
·Excellent insulation and dielectric performance
·Weatherproof and UV-resistant design
·Maintenance-free operation
·High mechanical strength
·Corrosion-resistant construction
·Long operational service life
·Reliable performance in harsh outdoor environments

Applicable Standards
·IEC 61869-1 – Instrument Transformers – General Requirements
·IEC 61869-3 – Additional Requirements for Inductive Voltage Transformers
·IEEE C57.13 – IEEE Standard Requirements for Instrument Transformers

Typical Wiring
Primary Side
·Connected phase-to-phase or phase-to-earth on the 22–24 kV distribution network.

Secondary Side
·Energy meters
·Voltmeters
·Protection relays
·Power quality analyzers
·SCADA and remote terminal units (RTUs)
·Synchronizing equipment

Typical Applications by Industry
·Utility Distribution: Revenue metering and feeder protection
·Renewable Energy: Solar and wind farm collector systems
·Industrial Plants: Outdoor switchyards and distribution systems
·Commercial Facilities: Primary distribution substations
·Mining: Outdoor electrical distribution
·Oil & Gas: Process power distribution
·Infrastructure: Airports, railways, and public utility networks

Key Features
·Rated system voltage up to 24 kV
·Designed for continuous outdoor operation
·Epoxy resin or porcelain insulated construction
·High dielectric strength and excellent environmental resistance
·Accurate voltage transformation for metering and protection
·Multiple secondary winding options available
·Maintenance-free, corrosion-resistant design
·Compliant with IEC 61869-1, IEC 61869-3, and IEEE C57.13 standards