Research On Risk Assessment Of Dynamic Stability For Northwest Yunnan Power Grid

With the rapid development of electric power industry and the further expanding scale of electric power network bringing huge economic benefits,but at the same time it bring about a great impact on many aspects of the electric power industry,especially the increasingly prominent dynamic stability problems. How to evaluate the dynamic stability becomes one of the important content of power system security assessmentfrom safety and economy aspects. The traditional power system security assessment methods commonly used deterministic methods and probabilistic assessment. The deterministicassessment method with large safety marginis, not considering the randomness,can not meet the requirements of the economic operation of the power system. And the probability assessment method did not consider the consequences of system fault impact,while considering the probability of the fault.In recent years,proposed the risk assessment method aiming at the drawbacks of traditional methods, which can quantitative assessed the safety of the system.from thetwo aspects of probability and severity of the fault. This paper first introduces the relevant research on security risk assessment of large area interconnected power grid,and presents a risk assessment method for processing dynamic stability.Then give thedynamicstability risk assessmentmodel of Northwest Yunnan power grid with the corresponding assessment method.Finally risk assessment of Northwest Yunnan power grid performed as an application. Through the case of different sending outputs scheme of Northwest Yunnan power grid, it gives that the risk of dynamic instability can be reduced by coordinating the sending outputs among sending ends of the interconnected power grid,and gives the method about how to determine the maximum external feeding power and corresponding operating mode of Northwest Yunnan power grid under the new method. And further compares the results of risk assessment of dynamic stability,and the result is about simulation of dynamic stability probability model which include state enumeration method、Sensitivity analysis methodand Monte Carlo method, verifying the superiority for interconnected power system by using Monte Carlo method.Meanwhile,it proves that by means of widely configuring PSSs 、applying rational scheme of HVDC modulation and the erection of regional liaison line, can reducethe dynamic instability risk,so can be the risk value reduction measures when dynamic instability fault.happen.