Research On Operating Risk Of Power Grid Considering Credible Contingency

Along with the arising scale of power system and the increasing uncertain factors in it,nowadays,secure and reliable operation become more and more important.And the traditional system secure analysis method has already been not able to satisfy the demand of current system operation.Against this background,power system risk theory was born at the right moment.The power system running risk and dispatch operation risk was studied in this article.Some theoretical innovation was made based on primary research.The power grid running risk is intended to reveal the real-time status risk of power grid.System risk index is calculated by assessing anticipatory contingencies.In this paper,a new contingency screening method was proposed and applied to power gird running risk assessment.Based on the definition of probability distance and probability ordered tree,it could quickly screen out the first k contingencies with maximum probability by using the designed greedy strategy.Assessment result in study case indicates that it has several advantages such as faster speed,greater adaptiveness and higher evaluation accuracy compared with existing methods.The power grid dispatch operation risk is intended to reveal risk in the procedure of dispatch operation.An entire method was proposed in this article to do risk assessment on both operation steps and the whole operation.Firstly,in order to considering the effect of operating elements,a power grid topology model was designed based on the linking relationship of operating elements.Secondly,in order to reveal risk in each operating steps,some decomposition precepts were designed according to different operation types.In operating steps assessment,3 conditions were involved to find out the risk point in operation.They are successful operation,successful operation accompanied with relevant element failure and failed operation.And the results were modified considering the effect of automatic bus transfer.Case study in practical system indicates that this method can reveal the risk of dispatch operation correctly and roundly.On the basis of power gird running risk and dispatch operation risk research,and also according to the practical system condition and the requirement of dispatcher,a power grid dispatching operation risk assessment system was developed.We designed the framework,functional module,data interface and UC of that system.It has already been running on a regional power grid for one year and it is well received by dispatchers.The power grid dispatching operation risk assessment system provides theoretical basis for dispatchers to realize the grid real-time running risk,to optimize the operating steps and to choose reasonable operating scheme.