Improved Harmony Search Algorithm to Compute the Underfrequency Load Shedding Parameters

Abstract

The power system continuously deals with frequency fluctuations. When a power disturbance occurs, the transmission system operators rely on the underfrequency load shedding (UFLS) scheme to address severe underfrequency (UF) events to maintain the frequency at the permissible level and prevent blackouts. Defining settings of a conventional UFLS scheme is a very complex problem due to the nonlinear nature of the frequency response, and the size of the problem is vast because of the number of UF-relays spread on the power system. The under or over total load disconnection produced by the wrong setting of the UF-relays can create secondary frequency events or even a total blackout. This paper introduces a novel method to compute an optimally parametrized conventional UFLS scheme in specific given operating conditions by formulating it as a constrained problem and using the Improved Harmony Search (IHS) algorithm to solve it. Since there is no previous knowledge of using IHS to solve the UFLS scheme, a numerical parameter sensitivity analysis (PSA) is developed to tune the parameter of the IHS algorithm. The IEEE 39-bus system was modelled in DIgSILENT® PowerFactory™ and used as a test system. The optimally parametrized conventional UFLS methodology presented in this paper reveals superior results against the conventional UFLS scheme, and the suitability of using the IHS algorithm is confirmed.

UFLS and Smart Load for Frequency Regulation in Electrical Power System: A Review

“…The most common computational techniques used in UFLS include genetic algorithms [55]- [57], fuzzy logic [58]- [60], neural networks [61], [62], particle swarm optimization [63], [64], adaptive neuro-fuzzy inference systems [65], [66], mixed-integer linear programming [25], [67]- [69], grasshopper optimization algorithms [70], and stochastic optimization [71], among others. UFLS schemes based on computational techniques are considered superior because they focus on optimizing their performance [72]- [76].…”

Optimize Ranking and Load Shedding in Microgrid Considering Improved Analytic Hierarchy Process Algorithm and Power Stability Index

“…There are many methods to keep the frequency stable in the system, such as: primary frequency control, secondary frequency control, voltage regulation, resistance-reactance cooperation, flexible AC transmission systems devices, and so forth. In such situations, the solution of load shedding is considered as a last line of defence to keep the system frequency stable and restore the frequency to an acceptable range [1][2][3].…”