Calculates the energy consumption per unit terminal cooling capacity of variable refrigerant flow rate(VRF)air conditioning systems and district cooling systems with constant primary pumps and variable secondary pumps and obtains the reasonable cooling radius that district cooling systems have higher energy efficiency than VRF air conditioning systems.

In light of some situations in Qingcheng 220 kV and 110 kV substation, such as irrational distribution、severe overload of main transformers、weak structure of 10 kV distribution network、some large power supply radius、poor power supply reliability, through the investigation and analysis for the present situation of distribution network, corresponding methods were proposed in the paper.

By taking it into no consideration the repugnant forces for safety support conditions and regarding elastic-plastic stress radius as being variable, the interaction between the elastic-plastic stress of No.

By taking it into no consideration the repugnant forces for safety support conditions and regarding elastic-plastic stress radius asbeing variable,the interaction between the elastic-plastic stress of No.

The paper introduces the relationship between load factor and efficiency of transformer, reasonable selection of radius of low voltage power supply, and using ripe and new energy saving electrical equipments, new materials and new technology.