WAMS-Based Online Disturbance Estimation in Interconnected Power Systems Using Disturbance Observer

Abstract

In the event of a generator loss or disturbance, the power system frequency declines quickly and overall system stability is at risk. During these scenarios, under frequency load shedding is triggered to restore the power system frequency. The main stage of modern adaptive under frequency load shedding techniques is disturbance estimation. However, the swing equation is widely used in disturbance estimation but has some critical estimation errors. In this paper, instead of using the swing equation we proposed the use of a disturbance observer to estimate the curtailed power. By making use of wide area measurements, a system frequency response model, which is a representative of the whole power system, can be realized in real time. Using different power system states of the developed model, a disturbance observer can be designed as well. The main advantage of the disturbance observer is that it can accurately estimate the disturbance magnitude and its location in a very short time. Further investigations show that by using the disturbance observer disturbances, which occur at the same time or at different times in different areas regardless of the magnitude or size, accurate estimations can be made. To ascertain the efficiency of the proposed scheme, simulations are done for a four-area power system using Matlab/Simulink.

Decentralized Stochastic Disturbance Observer-Based Optimal Frequency Control Method for Interconnected Power Systems With High Renewable Shares

“…Therefore, the aforementioned functional controller is not suitable for power systems with high shares of renewable energy sources like modern power systems. In [28], the for the first time, the disturbance observer has been developed for power system applications, more specifically for estimating the magnitude of the disturbance in power systems. However, the developed disturbance observer (DO) is applicable for protection applications in power systems, e.g.…”

“…Even in the event of a significant frequency deviation, each control area will retain its adjoining control areas interconnections, provided that the safe operation of its own system is not compromised. The aforementioned SFR model is a verified benchmark for frequency studies in modern power systems which is widely adopted for verifying the recently suggested methods [27], [28], [36].…”

Decentralized Robust Disturbance-Observer Based LFC of Interconnected Systems

“…However, the developed PI controller does not provide good performance, especially for the case high perturbed stand-alone power system. In [29] and [30], the external disturbance is estimated by an extended state observer (ESO) and a disturbance-observer, respectively. Then, a state feedback controller is designed.…”

T-S Fuzzy Control of Uncertain Fractional-Order Systems with Time Delay

“…At the same time, the external disturbance in the time-delay system is inevitable; in other words, such system will become more complex. However, for our known knowledge, there are still some studies on the control of FOSs with disturbances [43][44][45][46][47][48].…”