Small Island Power System Research Articles

The challenge of integrating renewable energy into the “small island” power system of Mauritius

A small island power system, such as that of Mauritius, has, by definition, a low inertial response, making it highly sensitive to network disturbances, occasioned, for instance, by the loss of generating units or sudden increases of demand. This is why, the integration of intermittent renewable energy is a major challenge, which the Central Electricity Board (CEB) is facing in its effort to reduce fossil fuel in its energy mix, Synchronous generators contributing to the overall system inertia will be replaced by renewable energy with a resultant increased exposure to grid frequency instability. Moreover, short circuit levels will be eroded by the new trend, introducing new complications to protection coordination. Solutions for satisfactory regulation are battery storage, drop mode operation of residue synchronous generators and the enforcement of output forecasts in RE contracts. New impedance values will influence short circuit currents. As a result, new modern smarter protection technologies will be necessary.

Electricity demand forecasting for decentralised energy management

Abstract The world is experiencing a fourth industrial revolution. Rapid development of technologies is advancing smart infrastructure opportunities. Experts observe decarbonisation, digitalisation and decentralisation as the main drivers for change. In electrical power systems a downturn of centralised conventional fossil fuel fired power plants and increased proportion of distributed power generation adds to the already troublesome outlook for operators of low-inertia energy systems. In the absence of reliable real-time demand forecasting measures, effective decentralised demand-side energy planning is often problematic. In this work we formulate a simple yet highly effective lumped model for forecasting the rate at which electricity is consumed. The methodology presented focuses on the potential adoption by a regional electricity network operator with inadequate real-time energy data who requires knowledge of the wider aggregated future rate of energy consumption. Thus, contributing to a reduction in the demand of state-owned generation power plants. The forecasting session is constructed initially through analysis of a chronological sequence of discrete observations. Historical demand data shows behaviour that allows the use of dimensionality reduction techniques. Combined with piecewise interpolation an electricity demand forecasting methodology is formulated. Solutions of short-term forecasting problems provide credible predictions for energy demand. Calculations for medium-term forecasts that extend beyond 6-months are also very promising. The forecasting method provides a way to advance a novel decentralised informatics, optimisation and control framework for small island power systems or distributed grid-edge systems as part of an evolving demand response service.

Integrating Clean Energy in Small Island Power Systems: Maldives Experience

Abstract Providing affordable, reliable clean electricity supplies is a major challenge small island nations face due to factors such as dispersed nature of their population in small individual islands, heavy dependence on imported fossil fuels for power generation and absence of economy of scale. The paper discusses the design of hybrid diesel-solar photovoltaic systems with energy storage with a sample involving five islands in Maldives. The study has shown that implementation of diesel-solar PV hybrid power generation systems with storage in small island countries increase energy security and they are economically and environmentally attractive.

Dynamic response and governor tuning of a long penstock pumped-storage hydropower plant equipped with a pump-turbine and a doubly fed induction generator

In this paper, the dynamic response of a long penstock pumped-storage hydropower plant which is equipped with a single pump-turbine and a doubly-fed induction machine, is analyzed in detail in generating mode. The pumped-storage hydropower plant is connected to a small island power system with thermal generation, and provides load–frequency control under the orders of an automatic generation control system. The output power of the pumped-storage hydropower plant is assumed to be controlled by the rotor-side frequency converter. The unit running speed is controlled by an isochronous PI governor. The dynamic response of the pumped-storage hydropower plant is analyzed by using a linearized reduced order dynamic model, which considers the elastic water column effects in the penstock. Two governor tuning criteria are proposed in the paper: one is devised from the root locus analysis of the plant dynamic model, and the other one is based on a Pareto approach. The proposed tuning criteria are compared with each other and with a recently published tuning criterion through a set of commonly used performance indexes and by means of simulations with a nonlinear dynamic model.

小規模離島系統における海水淡水化装置を用いた需給調整容量拡大手法

小規模離島系統における海水淡水化装置を用いた需給調整容量拡大手法

Load shedding on an isolated system

Underfrequency load shedding (UFLS), in previous generations shunned by the power supply industry as an admission of poor planning and operation, has become a generally accepted practice. There is by now a considerable body of literature on the subject. That literature, however, deals with the subject in the context of large interconnected power systems. Smaller, isolated power systems, which are more vulnerable to serious disturbances, have operating characteristics that require somewhat different guidelines, due to their lower inertia, limited reserves, and lack of access to off-system assistance. This paper reviews the objectives and principles of UFLS, and reports their application to a small island power system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>