ZX267 : Technical Guide for Power Industry Professionals

1. Introduction

In the power industry, dielectric integrity of electrical equipment is the cornerstone of safe, stable and reliable operation of power generation, transmission and distribution systems. The high voltage withstand test (also known as dielectric strength test, hi-pot test, or breakdown test) is a mandatory, industry-standard core diagnostic method to verify insulation performance, identify hidden insulation defects, and prevent catastrophic failures caused by insulation breakdown.

The ZX267 Series High Voltage Withstand Tester is a professional, high-precision testing instrument engineered to meet the stringent test requirements of the power sector. This guide provides a comprehensive technical overview of the series, including its working principle, core features, detailed specifications, model selection logic and standardized application in power system scenarios, serving as a dedicated technical reference for on-site engineers, test technicians and quality inspection personnel in the power industry.

2. Instrument Overview & Working Principle

2.1 Instrument Positioning

The ZX267 series is a dedicated power frequency high voltage withstand tester, optimized for the harsh on-site conditions and strict test specifications of the power industry. Unlike general-purpose testers for consumer electronics, this series offers a wide range of voltage, current and power configurations, covering insulation tests from low-voltage distribution components to medium-voltage power equipment. It is the ideal instrument for standardized dielectric strength tests of power transformers, power cables, switchgear, electric motors, power metering devices, insulating safety tools and other power assets.

2.2 Working Principle

The instrument applies a specified power frequency AC or DC high voltage to the tested equipment for a preset duration, while continuously monitoring the leakage current flowing through the insulation medium in real time. If the leakage current exceeds the preset alarm threshold, or insulation breakdown occurs, the instrument will immediately trigger an audible and visual alarm and cut off the high-voltage output automatically, ensuring dual safety of both the operator and the tested equipment. This working mechanism fully complies with the core requirements of IEC 60060 and GB/T 16927 high voltage test standards widely adopted in the power industry.

3. Core Technical Features

The ZX267 series integrates high-precision measurement, intelligent control and comprehensive safety protection, with core technical advantages tailored for power industry applications:

1. High-Accuracy Digital Measurement SystemThe instrument is equipped with a digital display system for both output voltage and leakage current, eliminating reading errors of traditional analog meters. Both voltage and current display accuracy reach ±5%, meeting the accuracy requirements of mainstream power industry test standards, and providing reliable, traceable test data for technical personnel.

2. Real-Time Leakage Current MonitoringThe tester continuously monitors and displays the dynamic leakage current of the tested equipment throughout the test process. This function enables technicians to observe the change of insulation performance under high voltage stress, identify incipient insulation aging and partial discharge defects that cannot be detected by simple breakdown judgment, and conduct a more comprehensive evaluation of the insulation state of power equipment.

3. Programmable Timing Control SystemThe instrument supports a timing range of 1~99 seconds with ±5% accuracy, as well as a manual test mode. This fully matches the standardized test duration requirements of power industry specifications. The preset countdown function ensures the consistency of test conditions, avoids human errors in test time control, and improves the comparability and repeatability of test results.

4. Customizable Alarm Current ThresholdTechnicians can set the alarm current value according to test standards and insulation characteristics of the tested equipment. The fast alarm and output cut-off mechanism not only protects the tested equipment from permanent damage caused by excessive breakdown current, but also strictly implements the pass/fail criteria of standardized insulation tests, ensuring the objectivity of test results.

5. Standard Power Frequency Sine Wave OutputAll models of the ZX267 series output a stable 50Hz sine wave, which is fully consistent with the grid power frequency. This feature ensures that the test conditions are completely aligned with the actual operating conditions of power equipment, avoids test result deviations caused by non-standard output waveforms, and guarantees the validity and authenticity of test data for power system assets.

4. Detailed Technical Specifications & Model Selection Guide

The ZX267 series provides multiple models with differentiated configurations to adapt to different test scenarios in the power industry. The key technical parameters and application recommendations are detailed below for technical personnel to select the appropriate model.

4.1 Universal Technical Specifications (All Models)

4.2 Model-Specific Parameters & Power Industry Application Recommendations

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5. Standardized Application in Power Industry & Operation Guidelines

For power industry technicians, correct application of the ZX267 series is critical to ensure test validity and operational safety. Below are the typical application scenarios and key technical operation points:

5.1 Typical Power Industry Application Scenarios

1. Handover and Preventive Tests of Distribution EquipmentFor 0.4kV low-voltage distribution boxes and ring main units, the ZX2670A/ZX2672A model is recommended, with a test voltage of 2kV~5kV in accordance with industry standards. For 10kV medium-voltage switchgear, the ZX2671A/ZX2671B model with 10kV output capacity can fully meet the 42kV power frequency withstand test requirements specified in GB 3906.

2. Insulation Verification of Power Transformers and Instrument TransformersThe ZX267 series can perform power frequency withstand tests on primary and secondary windings of transformers, as well as between windings and ground. For 10kV distribution transformers, the ZX2671A/ZX2671B model is applicable; for 35kV medium-voltage transformers, the ZX2674A/ZX2674B model with 30kV output capacity meets the test requirements of low-voltage windings and auxiliary insulation.

3. Power Cable Insulation TestsThe series supports DC withstand tests and leakage current measurement for power cables, the core method to detect cable insulation aging and water tree defects. For 0.6/1kV low-voltage cables, 5kV models are sufficient; for 10kV~35kV medium-voltage cables, the ZX2674A/ZX2674B model with 20kV~30kV DC output is recommended.

4. Preventive Tests of Insulating Safety ToolsThe ZX267 series fully meets the regular test requirements of insulating safety tools for power industry operators. 5kV models are suitable for insulating gloves and boots, while 20kV~30kV models are applicable for high-voltage insulating rods and electroscopes. The programmable timing and alarm functions ensure strict compliance with safety tool test specifications.

5.2 Key Safety Operation Guidelines

1. Before the test, ensure the tested equipment is fully de-energized, grounded and discharged to avoid electric shock hazards caused by residual charge.

2. The high-voltage output circuit must be reliably grounded. Operators must wear qualified insulating protective equipment and maintain a safe distance from the high-voltage terminal during the test.

3. Set the alarm current threshold according to test standards before the test, and perform a no-load test to verify the normal operation of the instrument's alarm and cut-off functions.

4. After the test is completed, reset the instrument to the zero-voltage state, and fully discharge the tested equipment before disconnecting the test wiring.

6. Conclusion

The ZX267 Series High Voltage Withstand Tester is a reliable, high-performance testing instrument that fully meets the technical requirements of dielectric strength tests in the power industry. Its complete model configuration, high-precision measurement system, intelligent control functions and comprehensive safety protection mechanisms make it an ideal tool for power industry technicians to perform equipment insulation tests, fault diagnosis and quality inspection. 

       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/