Effects of terminal connections on sweep frequency response analysis of transformers

Many problems can arise in power transformers, beginning from the moment they arrive at the sites where they are to be installed [1], [2]. Sweep frequency response analysis (SFRA) is used by many industries and manufacturers to assess the mechanical integrity of the core, winding, and clamping structure of power transformers. It usually involves the application of low-voltage (LV) signal (2 to 15 V) at one terminal of the transformer, over the frequency range 20 Hz to 2 MHz, and measurement of the response at another terminal, as shown in Figure 1 [1]. The amplitude and phase transfer function are then determined.