Section 5 Electrical Grids

**Chapter 10**

*Jožef Ritonja*

operation improvement.

**1. Introduction**

Agency [1].

**239**

**Abstract**

Robust and Adaptive Control

Synchronous generators produce almost 95% of the world's electricity. Even a small improvement in their efficiency represents huge savings. Electromechanical oscillations of synchronous generators are harmful—they cause losses and can even lead to instability. An additional control system, called a power system stabilizer (PSS), is used to damp the oscillations of synchronous generators. The commercial realizations of the power system stabilizers are based on the use of the linear control theory. The effectiveness of these power system stabilizers is small, because of the nonlinear and time-varying characteristics of the synchronous generators. The application of robust and adaptive control represents an adequate theoretical basis for ensuring optimal damping of the electromechanical oscillations in a wide operating range. This work reviews the applicability of the advanced control theories to develop power system stabilizers. The work is focused on selecting the appropriate robust and adaptive control theories for the power system stabilizer implementation. The applicability and advantages are presented of the sliding mode control and

the direct adaptive control, along with an evaluation of their impact on the

power system stabilizer, operation of synchronous generator

**Keywords:** sliding mode control, direct adaptive control, synchronous generator,

Synchronous generators are the most important electrical machines. They produce the majority of the world's electricity. In 2017, global electricity production was 25,721 TWh [1]. Assuming that the share of solar thermal sources is negligible compared to the share of solar photovoltaic sources, it can be estimated that about 98.2% of the total global energy is produced by electric generators. After analyzing the data, it can be estimated that synchronous generators produce 93.8% of the world's electricity and induction generators 4.4% of the total production of the world's electricity. The estimate is based on data for 2017. These, and also the following data, are obtained from statistics reports of the International Energy

An additional important point is that electricity trading and, thus, long-distance transmission of electricity are increasing significantly. In 2017, OECD countries produced 11,051 TWh of electricity, with a trading volume of 408 TWh,

s

for Synchronous Generator'

Operation Improvement
