Research On Web-based Power System Relay Protection Settings Online Verification System

Relay protection systems play a vital role in ensuring the secure and stable operation of power grids.In recent years,many large-scale system accidents at home and abroad are related to incorrect actions of relay protection.At present,relay protection settings are calculated offline and remain invariant during system operation.The fixed settings calculated based on the maximum and minimum benchmark operation conditions may not meet the requirements of selectivity and sensitivity in some special operating conditions,causing the protective relays to malfunction or refuse to operate.Therefore,it is necessary to verify and evaluate the reliability of the relay protection settings in the current operating condition.To this end,this thesis researches the development of a web-based power system relay protection settings online verification system.The main work and results are summarized as follows:A novel strategy for optimizing the online verification order of relay protection settings based on load importance is proposed to mitigate the blindness of the traditional verification mode with a random order.This strategy puts up an evaluation model of line importance from two aspects,i.e.,the structure and the state.From the structure aspect,a structural importance index considering load importance is proposed based on the power flow tracing theory and the characteristics of power grids.From the state aspect,a line state importance index is proposed based on the power flow transfer algorithm,with the security constraints of lines keeping in mind.Case studies show that the proposed method can accurately identify the key lines of the power system,thereby effectively improving the efficiency of online settings verification.A partitioning method for relay protection settings online verification is proposed based on multi-level graph partitioning algorithms.This method focuses on solving the problem of network partitioning in large-scale power grids and lays a technical foundation for realizing parallel calculation of online settings verification.The method first establishes a simplified topology model of the power grid for network partitioning and then uses a coarsening algorithm to compress the simplified topology to reduce its scale.Next,the method employs the spectral bisection algorithm to divide the coarsened topology into k parts,and finally adopts two graph partitioning optimization algorithms to optimize the division results.Case studies show that the proposed method can realize fast and even network partitioning of large-scale power grids.An implementation scheme of the web-based power system relay protection settings online verification system is proposed.The scheme combines the principle and application demands of online settings verification and is designed based on the MVC architecture and C#programming technology.When explaining the implementation scheme,the software architecture,database design plan,and implementation procedures of the online verification system are first introduced.Then,based on the demand analysis of online settings verification,the functional objectives of the system are delineated,and the functional modules of the system are devised in detail.Finally,some key technologies for realizing the system functions are introduced.