60KV Large Display Screen VLF Cable Testing Equipment 0.01Hz Ultra-low Frequency

Introduction: 

Compared to traditional power frequency withstand voltage and DC withstand voltage equipment, the VLF ultra-low frequency high voltage tester requires only 1/500th the test power capacity of power frequency equipment. Its lightweight design is suitable for substation field inspections, cable engineering on-site handover tests, and 2hydropower plant synchronous generator/large and medium-sized motor overhaul testing scenarios. The equipment has a built-in closed-loop voltage negative feedback circuit, completely eliminating the capacitance rise phenomenon. 

It is equipped with a 7-inch full-color capacitive touch screen, fully automatic voltage boosting sequence, and multi-level hardware safety protection. No manual operation is required throughout the process. Test data can be stored locally, printed instantly, and exported to a computer in one stop, balancing testing accuracy, operational safety, and outdoor portability.

Advantages：

1.With excellent adaptability to capacitive loads, it significantly reduces equipment size and power supply requirements.

Power cross-linked cables, generator stator windings, and power capacitors are all high-value capacitance test samples. When using a 50Hz power frequency withstand voltage test, an ultra-large capacity test transformer is required, making the equipment bulky, difficult to transport, and requiring a high-power external power supply on site. However, the VLF ultra-low frequency high-voltage tester, by reducing the output frequency, requires only 0.2% of the power supply for the same test samples. The weight of the entire set of equipment is significantly reduced, allowing it to be transported by small engineering vehicles. In the field, it can be powered by ordinary 220V mains power or a stable generator of 3kW or above, eliminating the need for a temporary high-power distribution vehicle.

2.Less insulation damage, and testing equivalence complies with mandatory industry standards.

Compared to DC withstand voltage testing: High-voltage DC can accumulate space charge inside the insulation layer, and long-term testing can easily cause irreversible damage to cable and motor insulation. Current power pre-testing regulations have restricted the use of DC withstand voltage. In contrast, 0.1Hz ultra-low frequency sine wave and power frequency AC have equivalent insulation testing effects, with extremely low damage to the insulation medium. It can accurately detect local weak points in the insulation and is the officially recommended handover/pre-testing solution by power grids, cable manufacturers, and hydropower companies.

3.The wiring is extremely simple, and a single person can complete the entire testing operation.

In contrast, power frequency resonant and variable frequency withstand voltage equipment requires multiple auxiliary components such as reactors, compensation capacitors, and voltage dividers, making on-site wiring cumbersome. This equipment only requires three lines: controller, booster, and test sample. It comes with dedicated shielded high-voltage cables, simplifying the wiring process by 70%. A single person can independently complete the entire process of wiring, boosting, withstand voltage testing, and discharging, significantly reducing the testing time for a single cable or motor.

All models and specifications：

Additional Notes on Load:
1.When the capacitance of the test sample is below 0.05μF, the waveform is distorted. A 0.05μF compensation capacitor from the original manufacturer must be used in parallel.

2.The formula for calculating the leakage current is: I = 2πfCU (I in mA, f in frequency, C in capacitance μF, U in peak value kV). The current can be estimated in advance before the test to set the protection threshold.

Adapted scenarios：

1. Cross-linked polyethylene power cable acceptance/preventive withstand voltage test

Suitable for 1.8/3kV~26/35kV full-specification rubber and plastic insulated cables. Test parameters are strictly set according to DL/T standards: acceptance test withstand voltage time 60 minutes, annual preventive test 15 minutes, test voltage uniformly taken as 3 times the phase voltage. Accurately detects local defects in the main insulation, joints, and terminals of the cable. It is a standard equipment for cable acceptance in municipal power grids, industrial park power distribution, and photovoltaic power plants.

2. Synchronous/Asynchronous large and medium-sized generator and motor stator winding withstand voltage test

Suitable for insulation assessment of synchronous generators in hydropower plants and thermal power plants, and high-power high-voltage motors in industrial applications after overhaul. The 0.1Hz low frequency can significantly reduce the stator anti-corona layer voltage drop, fully exposing hidden insulation defects at the winding ends. The test voltage is calculated according to the equivalent coefficient. Phase-by-phase voltage application and short-circuit grounding of non-test phases are simple operations.

3. Factory Quality Inspection of Power Capacitors and High-Voltage Capacitive Complete Sets of Equipment

Capacitor manufacturers conduct batch withstand voltage screening on their production lines. Utilizing low-frequency, high-load capacity, multiple capacitors are connected in parallel to complete insulation testing in one go, shortening the factory inspection cycle.

Partners：

Contact us

Contact Person: Christine

Mobile/Whatsapp/Wechat: +86 15123029885

Email: gold05@hy-industry.com