Research On Distribution Network State Maintenance Strategy Based On Risk Assessment

With the continuous expansion of power distribution grid,the number of distribution equipments has become larger and larger.In order to make sure that all the equipments can operate reliably,a large amount of maintenance tasks should be conducted.The maintenance strategy of equipments plays a leading role in assuring healthy operation of the equipment,improving distribution network reliability and safety and security as well as the economic efficiency.The power grid in China marches towards green power grid and strong power grid and aims at realizing the development objectives of reliability,safety,economic efficiency,high efficiency,with consequently higher production quality and management on electricity grid.The equipment perfonnance and quality have been developed a lot,the conventional maintenance after fault and periodic maintenance strategy are not applicable and the condition-based maintenance and strategy comes out and become the key means and technical support for optimization management of distribution network equipments management.Firstly,this paper establishes the health evaluation model of distribution equipment based on the fuzzy comprehensive variable weight theory.On the basis of evaluating the equipment assets and load losses to the power grid by equipment faults and from the present condition of power distribution network,risk evaluation of power grid equipments is carried out,which adopts a series of logical steps,giving the relevant risk indicators,mastering the probability and severity of the accident quantitatively,thus reflect the effects of the accident to the entire power system fully and maintenance strategy is formulated based on the operation risk level of the equipment.Then,propose the economic analysis model of the optimum maintenance proposal with minimum annual average cost.The annual average cost is the annual average cost of fund losses,operation cost,investment cost and etc.This model considers its own risk of the equipment and the risk caused to the power grid by the equipment fault.Maintenance of the equipment is expanded from the conventional single tier to the comprehensive tier of equipment and power grid.Finaly,this paper puts forward a new model for maintenance scheduling which considers load loss,grid active power loss and system risk as objective functions without violating restrictions.Also the paper makes a deep research of GA,SA.The method of GA integrated with SA improved arithmetic's convergent attribute.The propsed model and method are applied to a pratical system and numerical results verify the correctness and validity of them.