Resonance Analysis of Transformer District with Concentrated Compensation Capacitor in Low Voltage Topology Identification

The topology identification of low voltage transformer district plays an important role in the measurement of various service indicators of the power grid. And the reactive power compensation is usually carried out by means of centralized compensation capacitor, which may resonate with other inductors in the network, thus interfering with the topology identification work. In this paper, the equivalent network model of the low-voltage topology is sorted out and simplified into a single-phase network. Then, the resonant problem between the inductors such as load or transformer branch and the centralized compensation capacitor is analyzed. It is considered that the resonant frequency between the load and the centralized compensation capacitor is low, and it is not in the signal range used in topology identification. On the other hand, the resonant frequency between the transformer branch and the centralized compensation capacitor covers a large range, and it will obviously affect the topology identification, meanwhile the influence is limited by the action of active damping. Finally, the correctness of theoretical analysis is verified by simulation and site test.