In recent years

hidden failures of protection systems and security and stability control systems have become one of the main causes of power system blackouts all over the world. In the paper

the research on hidden failures of protection system is summarized in four aspects

including classification of hidden failure types

the probability model for hidden failures

analyzing methods of hidden failures’ impact on a power grid

and monitoring measures for hidden failures. The research on hidden failures of security and stability control systems has just started. Based on the characteristics of security and stability control systems

hidden failures that may exist in five links are pointed out

i.e. measuring

control strategy

setting

communication and voting pattern. The hidden failures resulting from the coordination problems among protection system

security and control system and power plant’s parameters related to the grid are also briefly discussed. Toward the end

the paper gives an outlook on the directions of future research for hidden failures: model building

assessment methods

application of research results

coordination between protection system and security and stability control system

and operation management of secondary equipment.