Research On Technology Of Data Acquisition In On-load Automatic Voltage Regulating Distribution Transformer

Voltage is an important index of quality of power supply. With voltage class of the grid constantly rising, it has higher demand for power supply and power distribution reliability. Use on-load voltage regulating distribution transformer which can regulate voltage on load is one effective measure. With the development of power electronic technology, use power electronic switch which is direct controlled by microprocessor to realize tap changing becomesThis paper studies a on-load automatic voltage regulating distribution transformer which has the function of real-time monitor voltage fluctuation and stabilizes the output voltage automatically. This kind transformer is comprised of non-contact on-load automatic voltage regulating tap changer and transformer itself which uses normal efficient distribution transformer. The tap changer uses zero passage solid state relay (SSR) as executive mechanism. The control system compares the monitor voltage value with the setting reference value and sends up trigger signal to SSR by trigger circuit to realize automatic changeover of tap changers. And it realizes basic stabilization of the second side voltage of transformer and has the function of on-load automatic voltage regulating.For the low reliability of transformer prototype with inductive loads, this paper finds four possible reasons through theory analysis. And according these this paper presents specific implementation plan to improve voltage regulating reliability. Meanwhile this paper designed three signal acquisition methods to acquire voltage waveform of high-voltage side. For low precision of data acquisition unit, this paper presented one design proposal which uses high acquisition precision oscilloscope-DS5202CA as data acquisition unit of on-load automatic voltage regulating distribution transformer. To eliminate single phase-to-earth fault of high-voltage side which could break down the data acquisition unit when data acquiring, this paper used 10000/200 potential transformer to realize electrical isolation.Theory analysis and experimental result proved that non-contact on-load automatic voltage regulating distribution transformer could regulate voltage automatically with no-impact when with no-load or resistive load. Voltage waveform shook in the regulating process when with inductive load. Meanwhile the second side voltage value drifted to 220V and the contactor backed to return state. So the voltage regulating failed. This paper presented the implementation plan through analyzing the experimental result intensively.This paper designed independent startup mechanism which used antiparallel thyristor and photoelectric coupler as main part, could solve the problem of the second side voltage value drifted to 220V and the contactor backed to return state when used contactor as startup mechanism. Through the experiment it made on-load automatic voltage regulating reliable and improve voltage regulating reliability.