Research On Prevention And Control Of Cascading Outages Based On PMU Measurement Technology

Large-scale blackouts of electrical power systems have been concerned in recent years.Most of the blackouts are caused by cascading outages,the blackouts have sounded the alarm for security and stability of electrical power systems.Social development calls for the security,stability and reliability of electrical power systems.So,it is urgent to research out effective measures in dealing with the cascading outages.The paper presents a new method for an optimal measurement placement of PMU called single shot security N-1 algorithms. The method considers single measurement loss and single-branch outage. It takes advantage of three steps: initial placement redundant placement and further optimal placement to achieve the aim of PMU's optimal placement.Then, the paper elaborates the definition and category of sensitivity analysis method. The paper derivates a mathematics model of static active power sensitivity based on DC power flow model, and verifies the correctness of this mathematics model by simulation.The paper proposed a strategy of prevention and control of cascading outages based on sensitivity analysis method. The strategy can be divided into three steps. Step 1: Obtaining the flow data through the modified DC power flow model based on PMU. Forming the high-risk branch set, and finding the most overload branch from the high-risk branch set. Step 2: Calculating the static active power sensitivity data of generator and load to the most overload branch, and dividing the control points into three degrees by the static active power sensitivity data. Step 3: Calculating the initial control amount firstly, then, find the optimal control amount by constraint condition, lastly, using the optimal control amount to control the electrical power systems to eliminate the line-overload. The strategy can also deal with one line overload and multi-lines overload to prevent the large-scale blackouts.