Instrument Introduction:
Combining modern digital frequency conversion advanced technology, adopting microcomputer control, automatic voltage boosting, reducing, and discharging, using photoelectric control to output 0.1HZ sine wave, and manual intervention is possible during the automatic voltage boosting process. Due to full electronization, it is small in size and light in weight, with a large screen liquid crystal display that is clear and intuitive, and can display the output waveform with print output. The design indicators fully comply with the electric power industry standard "General Technical Conditions for Special Testing Instruments for Power Equipment, Part 4: General Technical Conditions for Ultra-Low Frequency High Voltage Generators", and it is very convenient to use. Currently, both domestic and international methods use mechanical modulation and demodulation to generate ultra-low frequency signals, resulting in non-standard sine waveforms, large measurement errors, spark discharge in the high-voltage part, bulky equipment, and the second and fourth quadrants of the sine wave require high-power high-voltage resistors for discharge shaping, so the overall power consumption of the equipment is high. This product can overcome these shortcomings, and the protection functions are designed as follows:
Overvoltage protection: When the set test voltage value exceeds by ten percent (or 1.1 times), the instrument will stop for protection, with an action time of less than 20 milliseconds.
Overcurrent protection: Designed with dual protection for high and low voltage. The high-voltage side can perform precise shutdown protection according to the set value; the low-voltage side will stop for protection when the current exceeds the rated current, with action times both less than 20 milliseconds.
Instrument Principle:
Such huge equipment is not only bulky and expensive but also very inconvenient to use. To solve this contradiction, the test frequency is reduced, thereby reducing the capacity of the test power supply. Years of theory and practice at home and abroad have proven that 0.1Hz ultra-low frequency withstand voltage testing replacing power frequency withstand voltage testing not only has the same equivalence but also greatly reduces the size and weight of the equipment, with a capacity about one five-hundredth of the power frequency, greatly simplifying the test procedure, and having more advantages compared to power frequency testing. This is why developed countries generally adopt this method. The Ministry of Electric Power of China has commissioned the Wuhan High Voltage Research Institute to draft the industry standard "Test Method for Ultra-Low Frequency (0.1Hz) Withstand Voltage of Cross-linked Polyethylene Insulated Power Cables of 35KV and Below", and this method is being promoted in China. This instrument is developed according to this need in China. It can be widely used in AC withstand voltage tests for cables, large high-voltage rotating motors, and power capacitors.
Instrument Features
It has power overcurrent, high-voltage overcurrent, and protection functions, and the output voltage regulator cannot start high voltage if not returned to zero, making it a replacement product for traditional power frequency withstand voltage test equipment. The ultra-low frequency AC withstand voltage device is a new type of ultra-low frequency AC test device that mainly uses sine wave or cosine square wave as the output source. It is mainly used for non-destructive insulation withstand voltage tests of PE (polyethylene)/XLPE (cross-linked polyethylene) plastic power cables in the power sector. It has an international advanced level at the end of the twentieth century and a leading domestic level.
Technical Parameters:
1. Output Voltage: (KV) 30 50 80
2. Output Frequency: 0.1Hz, 0.05Hz, 0.02Hz
3. Load Capacity: 0.1 Hz max 1.1uF
0.05 Hz max 2.2uF
0.02 Hz max 5.5uF
4. Measurement Accuracy: 2.5%
5. Voltage Positive and Negative Peak Error: ≤2.5%
6. Voltage Waveform Distortion: ≤5%
7. Usage Conditions: Indoor, outdoor; Temperature: -10℃∽+40℃; Humidity: ≤85%RH
8. Power Supply: AC 50 Hz, 220V ±5%
