Capacitance tester UHV-323

powerresistancefor single- and 3-phase equipment

Overview
Single-connection wiring enables both DC winding resistance and turns-ratio testing. Multiple wired and wireless communication interfaces support function expansion and data transfer. Industrial-grade 7-inch display with a clear, simplified interface for efficient human–machine interaction.

Product parameters
The two-in-one distribution transformer testing system (direct resistance + turns ratio + energy efficiency level) is powered by a high-capacity built-in lithium battery (7.8AH) and can perform all three on-site tests.

Technical parameters
Direct resistance test
Output current: 20A, 10A, 5A, 1A, 0.1A, ≤10mA
Measuring range: 20A: 0.5mΩ–100mΩ; 10A: 1.0mΩ–300mΩ; 5A: 10mΩ–1.0Ω; 1A: 200mΩ–6.0Ω; 0.1A: 2.0Ω–60Ω; ≤10mA: 30Ω–50kΩ
Accuracy: ±(reading × 0.2% + 2 digits)

Turn ratio test
Measuring range: 0.9–10000
Accuracy: ±(reading × 0.1% + 2 digits) (≤500); ±(reading × 0.2% + 2 digits) (500–3000]; ±(reading × 0.3% + 2 digits) (>3000)
Resolution: 0.9–9.9999: 0.0001; 10–99.999: 0.001; 100–999.99: 0.01; ≥10000: 1

Operating conditions & appearance
Power supply: Built-in lithium battery, 7.8AH; Charger: AC 220V
Operating temperature: -10℃ to 50℃
Relative humidity: ≤90% (non-condensing)
Weight / Dimensions: 6.5 kg; 318 × 280 × 204 mm

Features

• Single connection performs both direct resistance and turns ratio tests, reducing setup time.
• Direct resistance mode supports automatic three-phase testing of Yn, Y and △ windings and computes three-phase unbalance; max output 20A for very low resistance measurement of LV coils.
• Turn ratio mode supports three-phase, single-phase and Z-type transformers, PT/CT ratio and polarity tests, and includes a blind test function.
• Multiple wired and wireless interfaces enable easy expansion, remote control and data export.
• Embedded Linux OS with dual-core A7+M4 architecture ensures secure, responsive operation and real-time measurements.
• Industrial-grade 7-inch display and integrated charger for reliable field use.

Technical specifications

• Model: UHV-323
• Functions: Direct resistance (winding DC resistance); Turns (variable) ratio; Energy efficiency level testing
• Direct resistance output currents: 20A, 10A, 5A, 1A, 0.1A, ≤10mA
• Direct resistance measuring ranges: 0.5mΩ–50kΩ depending on current/range
• Direct resistance accuracy: ±(reading × 0.2% + 2 digits)
• Turn ratio range: 0.9–10000; accuracy and resolution as above
• Power: Built-in lithium battery 7.8AH; Charger: AC 220V
• Operating temperature: -10℃ to 50℃
• Relative humidity: ≤90% (non-condensing)
• Weight / Dimensions: 6.5 kg; 318 × 280 × 204 mm

The necessity of transformer testing

• Power transformer is a device in the power system that uses the principle of electromagnetic mutual inductance to change the AC voltage. By adjusting the voltage, it facilitates power transmission, improves the economy of power transmission, and achieves long-distance power transmission. It reduces voltage at the user end to meet user needs! The main structure of a power transformer is composed of primary coils, secondary coils, and iron cores (magnetic cores), which play an irreplaceable role. The purpose of using a transformer comprehensive testing platform and transformer comprehensive testing instrument in preventive testing of power transformers is to ensure normal power operation and potential safety hazards.

Main application scenarios

• 1. Performance testing of newly put into operation transformers
• Conduct comprehensive performance testing on newly put into operation transformers, including testing of winding resistance, winding turn to turn voltage, no-load current, short-circuit impedance, and other parameters to ensure that the transformers meet design requirements.
• 2. Regular inspection of in-service transformers
• Regularly inspect the transformers in use, monitor the changing trends of various performance indicators of the transformers, and promptly identify potential problems.
• 3. Fault analysis of faulty transformers
• Conduct comprehensive testing and fault analysis on transformers that have malfunctioned, identify the cause of the fault, and provide a basis for subsequent maintenance.
• 4. Transformer winding status diagnosis
• By testing the resistance, inductance, and other parameters of the transformer winding, the mechanical integrity of the winding is determined, and problems such as winding deformation and short circuit are discovered.
• 5. Oil analysis of oil immersed transformers
• Perform chromatographic and infrared analysis on transformer oil, monitor changes in oil quality, and evaluate insulation status.
• 6. Transformer Capacity Test
• Test the short-circuit impedance, no-load current and other parameters of the transformer, calculate the actual capacity of the transformer, and provide a basis for load adjustment.
• 7. Transformer parameter testing
• Comprehensively test the technical parameters of transformers, including rated power, voltage ratio, winding resistance, etc., to provide basic data for subsequent maintenance and management.