Product Overview

The HET 25kVA exciter transformer is engineered for demanding high-voltage testing applications up to 16kV, featuring dual-range outputs (16kV/8kV) and exceptional partial discharge performance (<5pc). with="">ONAN cooling and advanced electrostatic shielding, it complies with IEC 60076-11 and IEEE C57.12.00 standards.

Electrical Specifications

Advanced Protection Systems

1. Overvoltage Protection

• Piezoresistors on all HV outputs

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

• Ground-referenced terminals via Class 1 surge arresters

2. Corona & Insulation Control

• 16kV corona-free HV bushings with triple corona rings

• Isovolumetric capacitance cores for precise voltage distribution

• Electrostatic shielding between all HV windings

Mechanical Construction

Enclosure Features

• 10-gauge steel housing with ANSI 61 gray finish

• Industrial wheel base (4× 200mm casters with brakes)

• Shell-type oil tank with 45L conservator and moisture indicator

Terminal Configuration

• LV terminals: High-density porcelain bushings

• HV terminals: Fiberglass-reinforced epoxy bushings

• Voltage-graded creepage distance ≥35mm/kV

Winding Technology

Advanced Insulation

• Cylinder-type winding with ±2% capacitance balance

• Inter-turn insulation (1.5mm Nomex® 410 layers)

• Electrostatic compensation shields with 5kV/mm gradient control

Dielectric Performance

• Impulse withstand: 175kV (1.2/50μs wave)

• Power frequency withstand: 35kV/min

• Partial discharge <5pC at 1.1Ur per IEC 60270

Operational Parameters

Thermal Performance

• Continuous operation: 100% load for 60 minutes

• Winding temp rise ≤65K at rated load

• Oil temp rise ≤55K at rated load

Environmental Specifications

• Altitude: ≤1000m ASL

• Ambient temperature: -25°C to +40°C

• Relative humidity: ≤95% non-condensing

Maintenance Protocol

Routine Service

• Oil testing: Quarterly BDV and moisture analysis

• Bushing inspection: Monthly visual checks for carbon tracking

• Winding resistance: Annual measurement with 100A micro-ohmmeter

Safety Procedures

• Always discharge test object through 10kΩ/100W resistor

• Verify ground connection integrity before operation

• Use Class E HV gloves when adjusting bushings