Abstract: In the planning of medium and low voltage distribution networks, building new distribution transformers is a common solution to solve customers' low-voltage problems，however, there are various reasons that can cause low voltage issues for customers,blindly adopting the new distribution transformer scheme not only cannot solve the problem efficiently, but also can cause investment waste.This article takes the project in planning work which solved the low voltage problem of customers as a case, analyzing some key steps such as problem cause analysis ,provide targeted treatment，list the fact that it is necessary to identify the root cause of the problem and adopt flexible, diverse, feasible, and economical solutions in order to timely and effectively address customer low-voltage issues and achieve precise investment goals.