Research On Operating Characteristics And Control Measures Of Regional Receiving End Power System

In China, with the rapid development of economy, accelerated modernization andurbanization process leads to large-scale network interconnection which contributes alot to the energy structural re-adjustment and optimal allocation. Expanded grid scale,generating unit capacity and operating voltage significantly makes power systemmore and more complex. It also brings new challenges in fields of security andstability. Long distance power transmission and substantial increase in load demandmakes the receiving end system voltage stability problem even prominent. In thisthesis, we mainly make some analysis on the receiving end power system. The workis as following:1. A typical receiving end system is deeply studied, which is gradual strengthened,so as to explore how the grid structure characteristics changes and what problems mayencounter, especially looped electromagnetically coupled problem. Then, based on thenetwork structure of target year, tools of power flow, continuation power flow andtransient simulation are used to analyze its static and transient stability. As a result,weak regions are identified and suggestions are given. In the study, a problem thatpower system is static instability but transient stability under some accidents is deeplydiscussed. The reason is give based on the theory of security region.2. Traditional current calculation method needs to re-build the nodal admittancematrix when it is used in breaking line fault analysis due to the introduction of newnode. So it is time-consuming to deal with a large number of expected contingencies.A new method is given in this thesis, in which compensation law is used to avoidmodifying the original nodal admittance matrix and phase component method is usedto compute the asymmetric part of system.3. In power system planning and security assessment, power flow calculationdivergence is found in many cases. In this thesis, a method based on sensitivity andmixed integer linear programming (MILP) to restore feasible solution is presented.Meanwhile the accuracy of sensitivity respect to various control measures and keycontrol measure identification is also discussed. New England-39and IEEE-118testsystem are used to validate the effectiveness of the method.