Research On Identification Of Power Grid And Power Flow Control Based On Power Flow Transfer

In order to ensure the stable operation of electric power system,this paper studies the identification of the vulnerable parts of the grid and power flow control strategy of the relevant line after the power flow transferred.To the power grid in stable operation,proposed a method for identifying important nodes and critical branches of the grid based on the improved Leader Rank algorithm.The importance value of each node in the grid can be calculated iteratively by giving each node an initial value and combining the structural characteristics and power flow information of the network as assigning weights.Then based on the importance of each node,the importance of each value can be obtained by the redistribution of the importance value of each node according to the power flow information of the grid.And the important nodes and key lines can be identified by sorting the importance values of nodes and lines.When a single line in the grid is disconnected and occurs power flow transferring,a method for identifying dangerous lines based on the power flow stability index is proposed.By analyzing the power flow transfer characteristics,the power flow transfer area is confirmed by searching the top K shortest path between the endpoints of the disconnected line.And screening the branches in the power flow transfer area to get the dangerous lines occurred by power flow transfer by using the power flow stability index and the changes of power flow of each branch.In this method,there are fewer branches in the power flow transfer area and the defined index is relatively simple.So,the amount of calculation is less.When the multiple branches are disconnected in a short period of time,propose a transmission section searching method based on the virtual power flow transfer model to the problem of power flow transfer.By establishing a power flow transfer model to reduce the dimensionality of the disconnected multiple lines,and convert the multi-branch disconnection problem into a single-branch disconnection problem.Then calculate the relevant parameters of the equivalent single branch and identify the branches that constitute the transmission section by using the power flow exceeding risk index to screen the branches in the power flow transfer area.In the calculation,the disconnection distribution coefficient when multiple branches disconnected at the same time is no need to recalculate by establishing virtual power flow transfer model.Which reduces the complexity of the calculation and unnecessary calculation.For power flow control of power grids including wind power,a method that combining power sensitivity and particle swarm optimization to rescheduling generator is proposed.Establishing ARIMA model to predict the output power of wind power and calculate the power sensitivity matrix of the power grid.Applying the power sensitivity matrix to the particle swarm algorithm to calculate the regulation amount of each generator under the control objectives and related constraints.The initialization of the particle swarm algorithm and the adjustment strategy of the inertia weight are improved to avoid the situation that the particle swarm algorithm is easy to fall into a local optimum.The introduction of power sensitivity avoids repeated power flow calculations for the power grid during the particle swarm optimization process and improves calculation efficiency.The methods proposed in this paper have been subjected to a large number of simulation calculations in standard calculation examples,verifying the correctness and superiority of the method in this paper.