Recognizing the non-coherent components helps to improve reliability of power systems. Considering stochastic failure of thyristor controlled series capacitor (TCSC) and its circuit breaker, a three-state model is proposed for the series-compensated line, based on which the analytical reliability model for the power systems is derived. Parameter and component non-coherences are analyzed based on the transmission capability of the line with TCSC and loss of load probability (LOLP) of the system. Coherence margin is defined and the critical condition of non-coherence is given. Impacts of compensation degree, reliability parameters, load level, and loading constraint on non-coherence are analyzed. The numerical results show that the system is non-coherent when the reliability parameter of the series compensator or its breaker is larger than the critical value. Less compensation degree, lower load level, or higher loading constraint yields higher possibility of reliability non-coherence. System non-coherence is more vulnerable to the series component than the circuit breaker of the TCSC. This work is supported by National Natural Science Foundation of China (No. 51277049).