1. Three independent test power supplies, maximum output current 0.5A;
2. The instrument sets sampling rate 10-20 kHz;
3. Maximum storage time for a single waveform is 6.4 seconds.
4. Transition resistance measurement range: Y/0 type transformer 1-40Ω,
Y type transformer 1-20Ω.
5. Measurement accuracy: 1-5Ω, Δ=±10%
5-40Ω, Δ=±5%
6. Time and synchronism error: Δ≤±1%.
7. Display: 240×128T, T6963C controller;
8. Printer: MP-40-8 panel-mounted front paper-loading printer;
9. Processing part:
80C320 high-speed 8-bit microprocessor. Program memory 32K;
Power-off data retention memory 512K bytes;
High-speed A/D converter, maximum sampling rate up to 400 kHz;
10. Power supply: 220V ±10%, power ≤200W.
11. Dimensions: 410mm×320mm×200mm.
12. Weight: ≤5kg
This instrument is mainly used for waveform analysis and parameter testing of on-load tap changers in power transformers. It can measure the transition waveforms of on-load tap changers in transformers with or without windings, and automatically analyze transition time, transition resistance, and three-phase asynchronism.
When the three-phase asynchronism exceeds a certain range, it will generate a large inter-phase circulating current. In a very short time, one contact has to bear the current of two branches, exceeding its current-carrying capacity, causing arcing during the switching process and burning out the switch. Abnormal transition resistance (first, transition resistance fracture; second, severe burning of the moving and static contacts of the diverter switch, with serious wear on the contact surface; third, poor connection of the transition resistance) may lead to a vicious cycle during voltage regulation, potentially causing sudden accidents such as transformer tripping during operation. Abnormal transition time, for example, if the time before three-phase bridging is long, indicates that the energy storage spring of the quick mechanism is aging and the speed is relatively slow. Generally, the phase difference of on-load tap changers in transformers is ≤2ms for double-resistor types and ≤5ms for four-resistor types; while the phase difference for autotransformer on-load tap changers is relatively large; generally, over 100 milliseconds is normal.
