Research on High-precision Monitoring Technology for Short-circuit Capacity of Power Grid based on Switching Operation

Traditional short-circuit capacity measurement methods require power outage operations on feeder loads and are difficult to achieve dynamic measurement effects. Therefore, this study proposes a non fault disturbance approach and designs a power grid short-circuit capacity measurement model based on non fault disturbance. The short-circuit capacity of the corresponding node is measured by the electrical parameter changes generated by the switching operation of reactive power compensation equipment on the common access point of the power grid. In the angle difference measurement of the short-circuit capacity measurement model in the power grid, the phase-locked loop method, which can ensure measurement accuracy and antiinterference ability, is mainly used for measurement. The results show that the proposed short-circuit capacity measurement technology exhibits high accuracy at voltage levels of $10 \mathrm{kV}, 35 \mathrm{kV}$, and 110 kV, with a maximum error of no more than 0.4%. Under the actual measurement of the 10 kV power grid, the four shortcircuit capacity measurements were all around 200 MVA, indicating that the researched and designed system is effective and stable. Overall, the high-precision monitoring model for shortcircuit capacity in the research and design of the power grid can achieve dynamic and accurate prediction, stable prediction, and further meet the requirements of smart grids such as relay protection short-circuit capacity verification, improving the stability and economy of smart grids.