Against the backdrop of continuous innovation in global cable testing technology, very low frequency (VLF) cable testers are becoming standard equipment in the power operation and maintenance sector due to their high sensitivity in detecting cable insulation defects. Leveraging over 20 years of technical expertise, Wuhan Goldhome Hipot Electric Co., Ltd. has developed the HMCOP series of VLF high-voltage generators, which integrate digital frequency conversion technology, intelligent control, and dielectric loss measurement to provide a comprehensive solution for preventive testing of 10kV to 35kV cables. This article offers an in-depth analysis of the core features of Goldhome's VLF cable testers.
Digital Frequency Conversion Technology and Precise Measurement
Goldhome's ultra-low-frequency cable testers utilize advanced digital frequency conversion technology, combined with microcontroller-based control, to automate the entire testing process-including voltage ramp-up, ramp-down, measurement, and protection. The output frequency range is adjustable across three levels: 0.1 Hz, 0.05 Hz, and 0.02 Hz, allowing users to select the appropriate setting based on testing requirements. Voltage accuracy reaches ≤3%, with a peak-to-peak voltage error of ≤3% and a waveform distortion rate of ≤5%, ensuring the accuracy and reliability of test data.
Most notably, the Goldhome device features dielectric loss (tgδ) measurement capabilities, enabling simultaneous measurement of the test subject's dielectric loss factor, capacitance, and insulation resistance during AC withstand voltage testing. This feature enables operators to comprehensively assess the overall aging condition and localized defects of cable insulation, providing multidimensional data support for equipment condition evaluation.
Intelligent Control and Multi-Level Protection
The core advantage of the Goldhome ULF tester lies in its intelligent integrated protection system. The device does not require manual setting of current and voltage protection values; it automatically calculates overvoltage and overload protection thresholds based on the capacitance of the test sample and the test voltage. In the event of sudden voltage or current fluctuations, the system detects discharge conditions in real time, with a protection response time of less than 20 milliseconds, ensuring maximum safety for both equipment and personnel.
The device employs optoelectronic control technology, with the controller connected to the low-voltage side of the high-voltage generator, achieving complete isolation between high and low voltages for safe and reliable operation. Additionally, the design incorporates a closed-loop negative feedback control circuit for high and low voltages, ensuring that the output is unaffected by capacitive effects and guaranteeing a stable and controllable testing process.
Convenient Operation and Data Management
In terms of user experience, the Goldhome ULF Tester is equipped with an 8-inch industrial touchscreen. The intuitive and clear interface displays output waveforms in real time. The device features built-in documentation, with the user manual and safety precautions stored directly within the unit, eliminating the need to consult paper manuals on-site.
Data management capabilities are equally robust. The device supports automatic storage and printing of test reports, with the capacity to save up to 64 sets of measurement data. By connecting to a computer via a USB interface, test data can be uploaded for further analysis and archiving. The device also features an electronic calendar function, ensuring that time information is retained even after a power outage.
Lightweight Design and Flexible Configuration
To meet the portability requirements of on-site testing, Goldhome employs a modular design. Models with a rated voltage of ≤80 kV use a single-connection configuration (where the booster is integrated into the controller), while models above 80 kV use a series configuration (with two boosters connected in series), significantly reducing the overall weight of the unit and enhancing its load capacity. Taking the VLF-80/1.1 model as an example, the controller weighs only 5 kg and the booster weighs 45 kg, making it easy to transport on-site.
Goldhome offers a comprehensive range of models for test subjects at different voltage levels: the VLF-30/1.1 is suitable for cables rated at 10 kV and below, the VLF-50/1.5 is suitable for cables rated at 20 kV and below, and the VLF-80/1.1 is suitable for cables rated at 35 kV and below.
