A flexible extrapolation strategy of oscillation center for large-scale power transmission bases

Abstract

The oscillation center may intrude into the generator group when out-of-step oscillation occurs in a large-scale power transmission base. This will lead to an “avalanche” generator tripping of the generator group and seriously affect the safety and stability of the system. Considering that the HVDC system has the advantages of large capacity and long transmission distance, it is often used as a parallel transmission corridor for large-scale power transmission bases. In addition, there is generally a certain reserve capacity in power plants. Starting from inputting reserve capacity and increasing the DC transmission power, a flexible extrapolation strategy of oscillation center based on energy rebalancing is proposed in this paper. The reserve energy at the sending system, the transfer energy in the transmission corridor, and the cut energy at the receiving end are counted. Then the energy transferred in the DC system is comprehensively predicted for complete extrapolation of the oscillation center, and the energy transfer constraints are formulated. The specific energy adjustment schemes of the sending system, power transmission corridor, and the receiving system are determined on the premise of meeting the stability of the system. Finally, the feasibility of this strategy is verified by simulation with the impedance trajectory of the generator and the change curve of power angle during the oscillation period.

Keywords

• Large-scale power transmission bases
• Oscillation center
• Energy rebalancing
• Flexible extrapolation strategy