Research On Non-contact On Load Automatic Voltage Regulating Distributing Transformer

The power network voltage, especially the rural power network voltage, is fluctuates when the load changes. And the fluctuate latitude always exceeds accepted value. It is harm to the electric device and people's life. For guaranteeing the reliability of power supply and decreasing the economic loss caused by voltage fluctuation, the distributing transformer with automatic voltage stabilizing function should be adopted to supply power.The thesis researches a kind of transformer which regulates automatically to stabilize output voltage in distributing power network. The transformer is composed by the non- contact on load automatic voltage regulating tap switch and transformer itself. Transformer itself is the energy saving distribution transformer which is used widely. Tap switch adopts solid state relays (SSRs) as operating unit, combining monolithic processor control technique. By detecting the secondary side voltage of the transformer, changing the switch automatically, it realizes on load automatic voltage regulating. The solid state relays are connected between primary side windings and neutral line of transformer. It adopts transition resistance to suppress the circular current which is occurred in the process of regulating windings. The secondary side voltage is divided into measuring signal, synchronizing signal and power supply signal by the isolating transformer, then is transmitted to the controller. If the measuring signal exceeds permitted range, the monolithic processor detects the synchronizing signal and sends triggering signal to the SSRs driving circuit at voltage zero-crossing point to regulate the operating state of the tap switches and change the operating tap joints of transformer automatically. Consequently, it stabilizes the secondary side voltage of transformer.The theory analysis and experiment result prove that the non- contact on load automatic voltage regulating distribution transformer prototype based on above-mentioned technology can apply to power and life load, it can run reliably in the very cold area. When adopting the electric power and electron component whose saturation pressure is under 2V as the high pressure side tap switch, it doesn't generate harmonic pollution. changing order of the tap is different, the developing mechanism of the circumfluence is different. When power network voltage fluctuating and load changing, it has the voltage stabilization function. When the power network voltage fluctuating between±10% U N1, the output voltage fluctuating latitude does not exceed±5% U N2, it makes that the fluctuating latitude declines ten percentage points.