Introduction  The gridding has been adopted by more and more power grid enterprises as its good performance in reliability management, line loss management and operating maintenance. At present, the power grid enterprises only set overall reliability targets instead of gridding reliability objectives, and the gridding still adopts standards of construction of power supply zones, which leads to high demands in power supply reliability but low planning and construction standard in cities with large differences in development.

  Method  The influence of political, economic, load and other factors on power grid was found through mathematical statistics, and quantitative results were formed. Then, different gridding categories were divided with cluster analysis. Considering the historical outage household numbers and proportion of planned outages, the relations between average outage time and total outage time in different types of power grids were sort out with analytic hierarchy process (AHP), and the reliability target of the planning area was reasonably allocated to the gridding.

  Result  The method meets the requirments of reliability objectives and actual demands in grid power supply construction, which is convenient for lean planning and construction of power network in gridding.

  Conclusion  The examples in this paper show that the method has strong guiding significance forreliability targets and distribution network construction.