Autonomous frequency response of different types of inverter-interfaced loads

In this paper, fast frequency response of different types of inverter-interfaced loads is discussed. Two inverter-interfaced loads are considered, and their short time-scale response in active power contribution is evaluated. First, a power system including conventional generating units with primary frequency controllers is modelled with conventional passive loads. Then, the control technique of different active load types, when they are equipped with droop controllers is discussed. It is shown that when a contingency event occurs, the behaviour of each load type in controlling frequency and thus their response in active power contribution are different. For the power system with a high demand side contribution in the primary frequency control, a suitable design consideration is provided in order to keep system frequency within threshold operating bound. Furthermore, to analyse the effectiveness of inverter-interfaced loads, their frequency response is compared to that of conventional generating units, revealing the potential of inverter-interfaced loads to provide considerably faster settling time and smaller overshoot. MATLAB/SIMULINK is utilised to simulate the power system.