The performance of a wide area damping controller (WADC) can be affected considerably if a photovoltaic (PV) power plant is integrated with the power system. A WADC using state feedback control law is proposed in this paper to eliminate the frequency oscillation of interconnected power system integrated with solar PV cell. Output power of the solar PV cell varies with irradiation. This variation in power degrades the performance of the WADC. Communication delay, which is always present in case of wide area measurement system (WAMS) also has a detrimental effect on the effectiveness of WADC. Another non-linear phenomenon which is always present in the WADC is the saturation of the actuator which reduces the effectiveness of the controller. The damping controller developed in this paper contemplates the effect of saturation of the actuator, time varying delay and changing operating condition using linear matrix inequality (LMI) criterion. The changing operating conditions are considered using a linear parameter varying (LPV) modelling of the system. After developing the LPV model of the system, the model is converted into a tensor product (TP) model. A supplementary damping controller (SDC) is considered in this paper as the WADC. The actuator of the damping controller is a thyristor controlled series capacitor (TCSC). A modified two area 11-bus power system with PV power plant and modified IEEE 39-bus power system with PV power plant is used as a test system to understand the usefulness of the designed controller.