Reliability Assessment Of Distribution Network Considering The Influence Of ICT System

Intelligent distribution network is an effective solution to solve the problem of large-scale grid-connected operation control and efficient utilization of distributed renewable energy,which is the future development direction of distribution network.As the supporting technology of intelligent distribution network,information and communication technology(ICT)is widely used in the monitoring,protection and control of distribution network.It plays an important role in improving the reliability of distribution network.However,with the increasing reliance on ICT by the distribution network,the negative impact of the ICT system on the reliability of the distribution network is becoming increasingly apparent.Therefore,by analyzing the influencing mechanism of ICT system to the distribution network reliablility,the reliability evaluation method of the intelligent distribution network is studied,and aims to improve the reliability assessment accuracy of the ICT and power fusion distribution system as well as providing reference for the planning and construction of distribution network.The main research works are as follows:Firstly,the coupling characteristics between the power system and the ICT system are analyzed.Considering the influence of component state,network transmission performance,topological structure and fault disposing mode of the ICT system on distribution network with distributed generation,the coupling mechanism of ICT system and power system in different scenarios of intelligent distribution network is anaylsed deeply to provide the basis for the construction of the reliability model.Secondly,reliability models of distribution network considering the effect of ICT system are established.Considering the effect of component lifetime and the state change rule,reliability models of ICT system and power system components are established.Considering the information link topology,characteristics of delay and error probability distribution,ICT system connectivity and performance reliability models are established.By analyzing the output intermittence of the photovoltaic and the operation correlation of the photovoltaic and energy storage,the combined output model of photovoltaic and energy storage is established.Then,an improved reliability assessment method for distribution network is proposed.A routing strategy based on depth-first routing algorithm is proposed for the ICT system.Based on the reliability models and considering the discreteness of information and the continuity of electric power,the non-sequential monte carlo algorithm is used to the ICT system and the sequential monte carlo algorithm is used to the power system.According to the sampled system states,the switch action sequence,routing and islanding strategy are taken into account to establish a reliability assessment method for the distribution network considering the influence of the ICT system.Finally,an test system example of the intelligent distribution network combined by the power system and the ICT system is established.The influence of the ICT system on the reliability of the distribution network is validated and quantified by calculating the index.Through calculating and analysing the sensitivity,the indirect impact on distribution network reliability of different network load rates and equipment failure rates are compared.Based on the analysis results,some suggestions are proposed for the intelligent distribution network planning.