Distribution System Reliability Evaluation And Design Considering Influence Of Typhoon

Typhoon weather creates great operation risk and economic losses to coastal powersystems， because the design standard of distribution system is always belowtransmission system, distribution facilities damage is particularly serious, thephenomenon which transmission network works well but distribution system failsappears frequently. Focused on the wind resistance capacity of medium voltagedistribution networks, a study concerned risk evaluation of distribution system intyphoon weather and reliability-based overhead distribution line design is performed inthis paper.Based on weather forecast information and typhoon wind field model, this paperextracts meteorological characteristics which impact line load: wind speed and direction,based on wind speed and wind direction wind load which wires and poles withstand iscalculated. Considering conductor’s weight, the wires tension and poles bendingmoment are calculated under wind loads. Combine tensile strength and bendingstrength, strength-stress function is established. Then line load of time-dependentreliability of overhead distribution line is calculated. Example analyzes the impact ofline routes, wire type and pole type on line load reliability.Because break failure is the main fault of distribution system under typhoonweather. Ignored other failure factors, based on the load reliability model of overheaddistribution line this paper evaluated distribution system reliability. Based onmeteorological forecast information, time-dependent load reliability model of overheaddistribution line is established., and in accordance with requirements definition fordistribution system reliability evaluation the power system reliability index undertyphoon weather is defined. Typhoon process is divided into several into periods, andline reliability index of each period is calculated. By segmentation algorithm thereliability index of distribution system is evaluated. By the result of assessment,operators can get the information about risk of operating in each period and probabilityof pope collapse in each line. Furthermore, the result provides the user message aboutpower outage, which will help them to develop measures of power ensure. Feasibilityand availability of the reliability model is also validated by example analyses.A planning model of overhead distribution lines is also established in this article.With Randomness of annual maximum winds velocity and gumbel distribution and loading reliability theory, this article builds the annual reliability model of eachdistribution system components.Considering the failure cost due to pole broken,combines investgetion cost and maintenance cost，this paper takes life cycle cost ofdistribution system as objective function and.span as constraint to built a design model,and uses genetic algorithm to solve this model. By above probabilistic planning model,planners and designers can get the risk of distribution lines’ load and obtain theoptimization with reliability and economy.