Technical Overview of the ZXXL-Y Transmission Line Parameter Test System

1. Introduction

The ZXXL-Y Transmission Line Test System is a new-generation testing instrument designed for power transmission line frequency parameter measurement. Aiming at the strong electromagnetic interference in on-site high-voltage line scenarios, the system integrates a frequency-conversion test power supply and DFT (Discrete Fourier Transform) digital filtering technology. It effectively suppresses power-frequency electric field interference, guarantees equipment operation safety, and delivers convenient, fast, and accurate parameter measurement for power testing technicians.

2. Core Technical Principle

The performance advantage of the ZXXL-Y system comes from its off-frequency testing architecture and digital signal processing technology. Conventional power-frequency testing methods are vulnerable to induction interference from adjacent live lines, which causes large measurement errors and even overvoltage damage to equipment. The ZXXL-Y system adopts a frequency-shift testing scheme: it injects test signals at non-power frequencies into the line, and uses the DFT digital filtering algorithm to extract valid test signals from mixed waveforms, filtering out power-frequency fundamental interference and various harmonic noises. This method fundamentally isolates power-frequency interference, realizing high-precision measurement under strong on-site electromagnetic conditions.

3. Key Functional Features

3.1 Full-parameter Measurement Capability

The system can quickly and accurately measure core line parameters including positive sequence capacitance, positive sequence impedance, zero sequence capacitance, and zero sequence impedance. It also supports measurement of mutual inductance and coupling capacitance between parallel transmission lines, fully covering the parameter testing requirements of overhead transmission lines in commissioning and operation stages.

3.2 Field-friendly Operation Design

For on-site testing scenarios, the system is equipped with a large LCD screen, a rotary mouse, and a built-in micro printer. Testers can complete parameter setting, real-time data viewing, and test report printing directly on the device without extra auxiliary tools. Meanwhile, the system adopts a simplified wiring design: all line parameter tests can be finished only by connecting the test down leads, which greatly reduces on-site wiring time and operation difficulty.

3.3 High-efficiency Integrated Hardware

The system takes a high-speed microcontroller as its core control unit, with an integrated hardware structure that improves equipment reliability and stability. The testing process is highly efficient: a single sequence parameter test can be completed within 1 minute, which significantly shortens total testing time for multi-parameter and multi-circuit line testing tasks.

3.4 Configurable Test Frequency

To adapt to different on-site interference intensities, the system provides three sets of selectable output frequency pairs: 42.5Hz/57.5Hz, 45Hz/55Hz, and 47.5Hz/52.5Hz. Testers can select the appropriate frequency according to on-site power frequency interference levels, so as to easily separate test signals from power frequency components and noise waves, ensuring high-precision measurement of weak signals under strong interference.

4. Detailed Technical Specifications

4.1 Electrical Input & Output

Input power supply: Three-phase AC 380V ±10%

Maximum output voltage: AC 300V, accuracy 1%

Maximum output current: 5A

Output signal frequency options: 42.5Hz/57.5Hz; 45Hz/55Hz; 47.5Hz/52.5Hz; 50Hz/50Hz

4.2 Measurement Performance

表格

4.3 Mechanical & Environmental Parameters

Dimensions: 535 mm × 435 mm × 360 mm (excluding moving wheels)

Net weight: 61 kg

Operating environment: Ambient temperature -15°C ~ +40°C, relative humidity < 90%

5. Anti-interference Performance

Strong power frequency induction is the primary challenge in live-line or adjacent-live-line parameter testing. The ZXXL-Y system has outstanding anti-interference capability, with the following verified indicators:

Allowable longitudinal induced voltage (after test power supply connection): < 350V

Allowable interference current (when line terminals are short-circuited to earth): < 40A

The system maintains accurate measurement when the amplitude ratio of output test signal to interference signal reaches 1:10.

This anti-interference level enables the equipment to operate stably in the strong electromagnetic environment of transmission corridors, eliminating the need for power outage of adjacent lines during testing, and improving both the safety and economic efficiency of on-site testing work.

6. Conclusion

The ZXXL-Y Transmission Line Test System provides a mature technical solution for power transmission line frequency parameter testing. Its frequency-conversion testing mechanism and DFT digital filtering technology effectively overcome the interference problem that plagues traditional power-frequency testing methods. With comprehensive measurement functions, user-friendly on-site operation, excellent anti-interference performance and reliable measurement accuracy, the system is applicable to commissioning tests, periodic inspection and fault analysis of transmission lines at all voltage levels. It can effectively improve the work efficiency of front-line testing technicians, and provide accurate basic data for power grid operation calculation, relay protection setting and line state evaluation.

 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/