ZXHQ-C Transformer Calibrator: On-Site Error Testing for Transformers

Abstract

Current and voltage transformers are core metering equipment within power systems. Their transformation accuracy directly determines the fairness of electric energy metering and the safe operation of power grids. Traditional transformer calibration instruments are limited by heavy weight, high minimum test current and poor environmental adaptability, which brings obstacles to field calibration work. This paper introduces the working principle, core technical features and performance parameters of the ZXHQ-C Transformer Calibrator, and discusses its engineering advantages in on-site calibration of instrument transformers.

1. Working Principle of ZXHQ-C Transformer Calibrator

The ZXHQ-C Transformer Calibrator is a novel automatic testing instrument dedicated for transformer error measurement. Adopting modern electronic signal processing technology, the equipment directly decomposes error signals generated by tested transformers. After real-time numerical computation, it synchronously outputs and digitally displays three key indicators of the transformer: percentage ratio error, in-phase error and orthogonal error.

Different from conventional calibration devices, the calibrator supports effective testing under 5% rated working current or rated voltage. This feature effectively solves the difficulty of low-load on-site calibration for instrument transformers, which commonly exists in power transformation stations.

2. Core Technical Characteristics

2.1 Human-Machine Interaction Design

The calibrator is equipped with a 320×240 lattice liquid crystal display, featuring wide viewing range and long-life backlight. The device adopts a full English operation interface with optimized layout. Ratio difference and angle difference data are displayed in enlarged fonts, which facilitates field technicians to read measurement results rapidly and intuitively.

2.2 Advanced Signal Processing Architecture

The instrument integrates proprietary hardware circuit with DSP digital signal processing technology. This design fundamentally eliminates measurement instability caused by resistance-capacitance phase-shift circuits widely adopted in older calibration equipment. Meanwhile, automatic sampling and automatic range switching functions are realized to improve testing efficiency.

2.3 Comprehensive Measurement & Judgment Functions

The calibrator can automatically identify polarity error and ratio error of transformers. It completely fulfills the measurement requirements for S-class transformers, which has long been a technical pain point in field calibration. All technical indicators comply fully with the standards JJG314-1993 and JJG314-1994. Upper computer software supports virtual instrument open interface, convenient for data uploading, storage and off-line analysis.

3. Main Technical Specifications

3.1 Operating Environment

Ambient temperature range: 5 ℃ ~ 40 ℃; relative humidity: less than 80% (at 25 ℃); working altitude: below 2500 m. Power supply: 50 Hz ±0.5 Hz, AC 220 V ±5 V.

3.2 Measurement Range & Resolution

In-phase component: 0.0001 ~ 200.0 %, resolution: 0.0001

Orthogonal component: 0.001 ~ 700.0 min, resolution: 0.001

Impedance: 0.0001 ~ 20.0 Ω, resolution: 0.0001

Mobility: 0.0001 ~ 20.0 MS, resolution: 0.0001

3.3 Working Conditions

Current test range: 1% ~ 149% In (In=5 A); 5% ~ 149% In (In=1 A)

Voltage test range: 5% ~ 149% Un (Un=100 V, 150 V, 100/√3 V)

Harmonic suppression ratio: >40 dB

Power consumption: <15 VA (without micro printer); <25 VA (with micro printer)

Overall dimension: 260 × 350 × 150 mm, net weight: 6 kg

4. Engineering Advantages in Field Calibration

The ZXHQ-C Transformer Calibrator possesses prominent portable advantages: compact size, light weight and low power consumption. It simplifies operation steps and realizes direct reading and rapid measurement, greatly reducing labor intensity for field test crews.

In practical power engineering scenarios, many transformers run under light load conditions. The capability of normal testing under 5% rated current/voltage enables the calibrator to complete error verification without adjusting station load, significantly improving the feasibility of live calibration work.

5. Conclusion

As a new-generation automatic testing equipment, the ZXHQ-C Transformer Calibrator combines mature DSP technology and optimized circuit design. It satisfies standard metering requirements and solves multiple practical difficulties including S-class transformer measurement and low-load field testing. With excellent portability and stable measurement performance, it is suitable for calibration work of current transformers and voltage transformers in power plants, substations and metering detection institutions, and provides reliable technical support for ensuring the accuracy of power metering systems.

GDZX is a manufacturer of power detection equipment, offering a diverse range of products with comprehensive models and providing professional technical support. Contact us at +86-27-6552607 or +86-17396104357.Website: http://en.gdzxdl.com/