（CT）and voltage transformers (PT) performance. It is mainly used to evaluate key parameters such as excitation characteristics, transformation ratio, polarity, and error curves of transformers, ensuring measurement accuracy and the reliability of relay protection.
Based on the latest market data and technical standards from 2025-2026, here is a detailed guide to this instrument:
1. Core Functions and Test Items
Modern transformer characteristic testers typically adopt a single-unit integrated design, with built-in high-power power supply and precision sampling modules, enabling the following tests without external current boosters or voltage regulators:
Volt-ampere characteristic test (excitation characteristics): Automatically plots the excitation curve of CT/PT, calculates the knee point voltage/current, and determines whether the iron core is saturated or damaged.
Transformation ratio test: Measures the actual transformation ratio to verify compliance with nameplate markings (supports multi-tap CT testing).
Polarity discrimination: Automatically determines subtractive or additive polarity to prevent wiring errors that could cause protection misoperation.
Error curve calculation: Automatically calculates and prints 5% and 10% error curves to evaluate the CT's transmission performance under short-circuit current (a key indicator for relay protection).
Phase angle error and ratio error test: High-precision measurement of phase angle error and ratio error (available in high-end models, used for metering-class transformer verification).
Demagnetization function: Automatically demagnetizes the CT after testing to eliminate the impact of residual magnetism on accuracy.
AC withstand voltage test: Some models integrate a simple withstand voltage function, allowing insulation withstand voltage testing from primary to secondary and ground.
Primary current injection test: Some high-end models support high current output (e.g., 600A) to simulate primary-side current for overall loop verification.
2. Recommended Mainstream Brands and Manufacturers in 2026
Currently, the domestic market is centered around Wuhan, forming a highly concentrated industrial cluster with extremely high cost-performance products that fully meet the stringent requirements of State Grid and China Southern Power Grid.
Leading Domestic Brands (high market share, mature technology)
Wuhan UHV Electric Power Technology Co., Ltd.:
Features: Leader in the 2025 industry evaluation. Adopts “military-grade sampling chips + AI intelligent algorithms”, with excellent data stability under strong electromagnetic interference. Its equipment is listed as the first choice by State Grid, China Southern Power Grid, and many large testing institutions.
Advantages: Fully automated test process, no need for manual parameter setting, one-click generation of reports compliant with DL/T standards.
Wuhan Huadian Keyi Electric Co., Ltd.:
Representative model: HKHG-F2 series.
Features: Established manufacturer with a rich product line, covering from portable to large desktop models, with a comprehensive after-sales service network.
Wuhan Weian Electric Power Technology Co., Ltd.:
Features: Focuses on high cost-performance and durability, offering a three-year warranty and lifetime repair service, with a good reputation among small and medium-sized power engineering companies.
Services: 24-hour technical support and free software upgrades.
Yangzhou Tuopu Electric Technology Co., Ltd.:
Representative model: TPHGC-E series.
Features: Excellent portability, lightweight single unit (<18kg), suitable for field and high-altitude operations; comes with a built-in micro printer and USB data upload function.
Shanghai Zhengyuan Electric, Beijing Jinzhengmao (LY series):
Have a high market share in East China and North China, with products compliant with GB1207/GB1208 national standards.
International Brands
Austrian OMICRON, American Megger:
Features: Extremely high accuracy (up to 0.05 class), extremely powerful functions (supporting frequency domain analysis, transient characteristic testing), but expensive (usually 100,000-300,000 RMB), and relatively complex operation.
Suitable for: Provincial electric power research institutes, ultra-high voltage bureaus, research institutions, and occasions with extreme requirements for measurement accuracy.
