Product Overview

The HET 41.5kVA exciter transformer provides three voltage ranges (24kV/12kV/6kV) in a single unit, featuring ultra-low partial discharge (<5pC) and <5% impedance. With ONAN cooling and advanced electrostatic shielding, it meets IEC 60076-11 standards for precision high-voltage testing.

Electrical Specifications

Advanced Design Features

Triple-Voltage Operation

• Independent winding taps for each voltage range

• Precision voltage ratio (±0.5% accuracy)

• No-load tap changer for safe switching

Dielectric Performance

• 24kV corona-free bushings with triple corona rings

• Electrostatic shielding between all windings

• Isovolumetric capacitance cores for stable voltage distribution

Protection Systems

1. Overvoltage Protection

• Piezoresistors on all HV outputs

• Zinc oxide arresters (20kA rating per IEC 60099-4)

• Dual grounding points with 10mm² copper straps

2. Insulation Monitoring

• Inter-turn insulation (2mm Nomex® layers)

• Winding temperature sensors with alarm contacts

• Oil level indicator with minimum mark

Mechanical Construction

Enclosure Features

• 12-gauge steel tank with ANSI 61 gray finish

• Heavy-duty wheel base (4× 250mm casters with brakes)

• Shell-type oil tank with 60L conservator

Terminal Configuration

• LV terminals: Porcelain bushings (creepage ≥25mm/kV)

• HV terminals: Fiberglass-reinforced epoxy bushings

• All bushings have grading rings for field control

Installation & Maintenance

Commissioning Requirements

• Minimum 1.5m clearance from grounded surfaces

• Initial oil BDV ≥50kV (2.5mm gap)

• Pre-operation IR ≥10,000MΩ (2.5kV megger)

Service Schedule

• Monthly: Inspect bushing contamination

• Quarterly: Oil DGA and moisture analysis

• Annual: Complete winding resistance test

Typical Applications

• Extra-high voltage cable testing

• GIS (Gas Insulated Switchgear) commissioning

• Power transformer routine tests

• Research labs requiring multi-voltage testing