The crucial issue of loss of synchronization in postdisturbance conditions may lead to blackouts if corrective action is delayed. The complication increases due to large computation burden and time for wide-area network where thyristorcontrolled series compensator (TCSC) is used as controller for transient stability enhancement. The trade-off in accuracy and speed in generating control law using linearized models becomes ineffective for changed operating scenarios. In addition, forming multi-machine linearized model becomes challenging when TCSC appears as non-separable element of a dense admittance matrix, which can be separated as a control variable in single-machine infinite-bus system. Overcoming the limitations of linearized controllers, the present paper verifies the Kuramoto mean-field condition using Kron reduction with non-trivial transfer conductances for unstable post-fault scenario. To regain synchronization effectively, necessary TCSC compensation has adjusted network parameters as proved by MATLAB simulations performed on 12-bus system, where real-time data is acquired by phasor measurement units.