Accuracy Verification of PLL-Based Acquisition System for Low-Cost Applications

In the last years, strong changes of power network architectures and operation have led to make use of huge quantities of instrumentation, spread around the grid. In fact, there is a strong need to perform measurements (very often accurate measurements) of electrical quantities in many nodes of the network, mainly due to the strong penetration of distributed generation. In Medium Voltage networks, the challenging requirement of having accurate measurement systems and with affordable costs has grown rapidly. Recently, the main Italian utility has asked for such kind of instrumentation. Its main feature must be to perform accurate measurements in all actual conditions. In this paper, a low-cost acquisition system, designed to achieve the aforementioned characteristics is presented. It makes use of a PLL technology. This way, critical acquisition issues, and in particular spectral leakage, are overcome, as shown from the presented results.