ZnO varistor is the core element of surge arresters.We investigated the electrical characteristics of rare earth doped ZnO varistor ceramics.Multiple donor dopants(Al

3+

Ga

3+

and Y

3+

) were employed to improve the comprehensive performances of ZnO varistor ceramics.The leakage current of rare earth doped ZnO varistor ceramics decreased noticeably with Ga

2

O

3

dopants.The Ga

3+

dopant occupies the defect sites of grain boundaries and increases the barrier potential of ZnO varistor ceramics

so the leakage current is effectively inhibited.Y

2

O

3

is primarily located around the grains

which restrains ZnO grain growth

increasing the voltage g

radient.The Al

3+

enters the lattices of ZnO grains

decreasing the grain resistance; thus

the residual voltage ratio can be controlled at low levels under a high impulse current.These multiple donor dopants can aid in engineering high-quality ZnO varistors.When being doped with 0.5 mole fraction Ga

2

O

3

0.9 mole fraction Y（NO

3

）

3

and 0.2 mole fraction Al（NO

3

）

3

the sintered varistors showed optimal electrical properties with a nonlinear coefficient of 83

residual voltage ratio of 1.56

leakage current of 1.44 μA/cm

2

and voltage gradient of 479 V/mm.This study helps to improve the protection effect of surge arresters

and realizes deeply suppressing the overvoltage of power systems

especially the UHV systems.