Optimal Estimation of Under-Frequency Load Shedding Scheme Parameters by Considering Virtual Inertia Injection

Abstract

Under-frequency load shedding (UFLS) schemes are the latest safety measures applied for safeguarding the integrity of the grid against abrupt frequency imbalances. The overall inertia of electrical power systems is expected to decrease with an increased penetration of renewable energy as well as elements connected through power electronic interfaces. However, voltage source converter-based high voltage direct current (VSC-HVDC) links can provide virtual inertia through a control loop that allows for a reaction to occur at certain frequency fluctuations. This paper evaluates a UFLS scheme that considers the injection of virtual inertia through a VSC-HVDC link. A genetic algorithm (GA) is used to determine the location of the UFLS relays, the activation threshold of each stage, the delay time and the percentage of load shedding at each stage. It was found that the virtual inertia causes the nadir to delay and sometimes reach a greater depth. Furthermore, the implemented GA approximates the frequency response to the limits set with the constraints, reducing the load shedding but achieving a steeper nadir and a lower steady-state frequency level than traditional UFLS. The simulations were performed using the IEEE 39-bus test system.

Data for Optimal Estimation of Under-Frequency Load Shedding Scheme Parameters by Considering Virtual Inertia Injection

“…In electric power systems (EPSs), frequency serves as an indicator of the equilibrium between power generation and demand. Therefore, when generation exceeds demand, frequency tends to rise, signaling an abundance of available power; conversely, if demand surpasses generation, the frequency decreases, indicating strain on the system [1,2]. Maintaining a stable frequency is essential for ensuring the reliability and efficiency of EPSs, as deviations from the standard frequency may lead to disruptions, equipment damage, or even blackouts [3,4].…”

“…However, these strategies modify the dynamic behavior of the power system, and it is necessary to develop UFLS schemes that consider inertia emulation by HVDC links. Thus, in [1], a study was presented in which a GA was used to determine each of the parameters of the UFLS scheme when considering the inertial response of the HVDC VSC links, but the configuration data and the results obtained were not included in detail. For the development of the simulations in which the data were used, the Digsilent Power Factory electrical systems simulation software version 2018 (Gomaringen, Germany) was used.…”

“…Finally, Case 6 considers the optimized UFLS scheme, the operation of the HVDC VSC link, and the activated inertia emulation control loop. The case studies are further developed and analyzed in depth in [1]. Thus, the dataset published in this article includes the data used in the development of [1] and also includes the data corresponding to its results.…”

“…The case studies are further developed and analyzed in depth in [1]. Thus, the dataset published in this article includes the data used in the development of [1] and also includes the data corresponding to its results.…”

“…A GA was employed to determine the optimal configuration of the UFLS scheme, and these data are included as input to this work. Finally, both the configurations of the UFLS schemes evaluated in [1], and the frequency and time values with which the result curves were constructed are included. With the data provided, it is possible to make comparisons and replicate the work carried out in [1]; furthermore, other systems can be adapted to test the interaction of the proposed methodology.…”