Research On The Automatic Connection Technology Of Virtual Terminators In The Secondary Side Of Smart Substation

Smart substations use optical cables instead of a large number of cables and achieve the transfer of information between IEDs(Intelligent Electronic Devices)through networks such as GOOSE(Generic Object Oriented Substation Events)and SV(Sampled Value).In order to facilitate the smart substation design,operation and maintenance,the concept of virtual terminator was proposed in China.The work of connecting virtual terminators has become the main content of the second design of smart substation.At this stage,virtual terminator connection of the domestic smart substation mainly relies on the designer in the institute to complete manually,which is heavy-duty,time consuming and error prone.It may result in hidden dangers to the safe operation of smart substations.Therefore,it is the current research direction to find methods to connect connect the virtual terminators automatically between IEDs of smart substations with computers.There is a huge difficulty in using the traditional string matching method to connect virtual terminators automatically for a few reasons.For example,the variety of IED types in smart substations,different equipment manufacturers have different forms of virtual terminators of the same type,and the rules for connecting virtual terminators are very complicated.With the development of machine learning technology and the increasing number of smart substations in operation,it is possible to learn the rules of virtual terminator connection in intelligent substations using machine-learning methods.The main contents of this paper are as follows.For the problem that there are more secondary equipments in smart substations and their interconnections are complex,this paper presents a secondary equipment association template library based on the smart substation electrical bay and IED functions.The secondary devices are divided into typical secondary bays by the electrical bay and the IED function.Then the configuration and logical information flow diagram of IEDs related to typical bay are given to obtain the secondary device association template library.According to the secondary device association template library,IEDs connected with the pending IED can be obtained,and the problem of all-station virtual terminal connection is decomposed into the problem of the virtual terminal matching between the connected IEDs.In view of the drawbacks that the virtual connection in the current design institute relies heavily on the designer's familiarity with the virtual connection in intelligent substations,this paper proposes an automatic matching method for virtual terminators based on k-Nearest Neighbor(kNN)method.In this method,the virtual connection information is acquired from the existing smart substation SCD file as the sample set.The input terminator of the sending IED and the virtual terminator of the output virtual terminator of the receiving IED connected thereto are combined as the test data,and the test data and the sample Set the distance,and then use the voting method to select the appropriate combination of virtual terminator as the matching result automatically.At the same time,the method of calculating the credibility of automatic matching results is given.In view of the problem that different equipment manufacturers have different forms of virtual terminators of the same type,and to obtain the measurement of virtual connection distance in kNN learning method,a method based on weight vector optimization is proposed to calculate the virtual connection distance.By analyzing the characteristics of components in the virtual connection,we calculate the distance between the virtual connection components using the expertise of smart substation.The optimization model of distance weight vector is built by using the virtual connection samples.Then the particle swarm algorithm is used to calculate distance weight vector,which can represent the virtual connection characteristics of the IEDs.Finally,based on the actual smart substation,this paper tests the proposed virtual terminator automatic connection method and gives the test index.The results show that the method can automatically connect virtual terminators,reduce the workload of substation construction and improve the design quality of virtual terminators.