A analysis method of the problems of interconnected systems and the decentralized controller design method are presented in
this paper． That the topology of the interconnection is arbitrary and the exchanged information between subsystems is lost cause the unreliable
link． Firstly，the stochastic variable responsible for the situation of the lossy communication is regarded as a source of model uncertainty，
and the system is modeled in linear fractional transformation． Then the robust control theory is employed for system analysis，
and the largest probability of communication failure，which is tolerated by the interconnected systems keeping mean square stable，can
be obtained． Decentralized state feedback controllers are designed to ensure that the whole systems are mean square stable for a given
communication failure rate，based on the technique of linear matrix inequalities． Finally，an illustrative example of power network
which is a part of China southern power grid is presented finally to show the effectiveness of the proposed model and method． Simulation
results demonstrate that when the communication faults occur between the power components in the China southern power grid，using the
method described in this paper can make the network well designed and wide-area controlled and the local power network mean square
stable．