Optimal feedback path selection for interconnected power systems using load frequency control strategy

A Hasib Chowdhury,Md Mijanur Rahman,Md Alamgir Hossain

doi:10.1049/gtd2.12047

Abstract

The main goal of an interconnected power system is to transfer power from one area to another while the network frequency and tie-line flow remain within the prescribed limits. However, both of these quantities may violate their desired values during this transfer due to disturbances in the network. This paper proposes a stratagem for choosing the right feedback path for an interconnected power system to maintain the system frequency and tie-line flows within the prescribed limits while external disturbances exist. Area control error (ACE), a combination of frequency error and tie-flow deviations, is used as the performance indicator. In the proposed approach, feedback control is designed using active disturbance rejection controller (ADRC) based load frequency control to tackle ACE. It is observed that the individual load change monitoring is sufficient for selecting the right feedback paths rather than the consideration of simultaneous load changes of all load centres. The effectiveness of the proposed controller for selecting the feedback paths has been tested by conducting several case studies. The results demonstrate that the proposed controller can reduce transient magnitude around 57% for ACE, 55% for frequency error and 72% for tie-line error as compared to the PID controller.

Highlights

Power generation and demand of interconnected power systems should be exactly matched by controlling the speed of synchronous machines
Regulation of real power output of generating units in retort to change in system frequency and tie-line power interchange within specified limits is known as load frequency control (LFC) [2]
It is seen that the minimum Area control error (ACE) belongs to the feedback path L1G1 L3G2 and L1G3

Summary

Introduction

Power generation and demand of interconnected power systems should be exactly matched by controlling the speed of synchronous machines. This sense of balance must be kept up during load changes and instabilities, such as equipment disconnecting issues [1]. The two most important equilibrium points in a power system, mainly depend on the balance of active and reactive power supply, respectively. Without balancing these two factors, the system will reset at a new value and, the equilibrium points will drift. The primary task of LFC is to uphold the system frequency to its predetermined value

Methods

Results

Conclusion