Precision Instrument for Extra-High Voltage Systems

Engineered for critical 50kV/60Hz applications, the LQHVF delivers laboratory-grade accuracy with field-deployable reliability. The optimized 500pF capacitance provides:

• Ultra-low dielectric dissipation (<0.2%)

• Precise voltage measurement with ≤±1% accuracy

• Partial discharge detection within complete test systems

• Superior thermal stability with ONAN cooling

50kV

Technical Specifications

Advanced PD Test System Performance

Complete Test System Integration

The <10pC PD specification applies to the entire measurement chain, including:

• Coupling capacitor (this unit)

• Measurement impedance

• PD analyzer

• Shielding and grounding system

Calibration Requirement: System verification per IEC 60270 using calibrated pulse injector

Innovative Structural Design

Corona Rings

Optimized geometry

Removable design

Ly Arm

Measurement interface

BNC output

Hy Arm

High-voltage terminal

50kV rated

Removable Base

Stabilized platform

Leveling feet

Oil-Immersed Construction

High-grade mineral oil with dielectric strength >60kV/mm

Benefit: Enhanced arc suppression and thermal management

Modular Design

Quick-disconnect components

Benefit: 10-minute field assembly

ONAN Cooling

Natural oil/air convection

Benefit: Stable operation at full load

Dual-Function Operation

Voltage Division

Application: RMS voltage measurement

Accuracy: ≤±1% at 60Hz

Output: 50V at 50kV input

PD Coupling

Application: Partial discharge detection

Sensitivity: <10pC system performance

Bandwidth: 30Hz-500kHz

Technical Note: The 500pF capacitance provides optimal impedance for 50kV/60Hz systems, balancing PD sensitivity and high-frequency response

Thermal Management

• ONAN System: Oil Natural Air Natural cooling

• Thermal Performance: <50°C rise during 60-min operation

• Operating Protocol:

• 60 minutes continuous at 50kV (100% UH)

• Followed by 90-minute cooling period

• Cooling Requirements: 30cm clearance around unit

Compliance & Applications

Standards Compliance: IEC 60270:2000 (PD), IEEE 4-2013 (Testing), ANSI C57.13 (Accuracy)

Critical Applications:

• Factory acceptance testing of 50kV switchgear

• On-line PD monitoring in substations

• Dielectric loss measurement in power transformers

• High-voltage research at 60Hz

• Calibration of protective relays

Operational Protocol

Preparation

1. Assemble components on stable surface

2. Connect Ly-arm to measurement device

3. Ground base with ≥12mm² cable

Energization

1. Ramp voltage gradually (≤5kV/s)

2. Monitor for 60 minutes maximum

3. Verify oil temperature <85°C

PD Measurement

1. Connect to PD analyzer via Ly-arm

2. Calibrate system with pulse injector

3. Use double-shielded coaxial cables

Shutdown

1. De-energize system

2. Wait 10 minutes for discharge

3. Disassemble components

Why This Instrument?

Dielectric Precision

<0.2% loss for accurate measurements

System Integration

<10pC PD system performance

Thermal Stability

ONAN cooling for continuous operation

Frequency Optimized

Designed for 60Hz power systems