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Abstract

The paper raises the issue of optimizing the control of the rural low voltage microgrids. Microgrids can operate in a synchronous mode with grids of distribution system operators and in an island mode. We can distinguish two control strategies in microgrids: one approach based on centralized control logic, which is usually used, and another on decentralized control logic. In this paper we decided to present the approach based on the distributed control, combining the efforts of the distributed cooperative control and modified Monte Carlo optimization method. Special attention has been paid to the impact of the order of processing particular devices’ groups on results of optimization calculations. Moreover, different scenarios of behavior of the microgrid control system with respect to the communication loss have been also presented. The influence of the issue of continuity of communication between particular devices’ groups on the possibility of carrying out the optimization process has been investigated. Additionally, characteristics of power loads and generation of electricity from small renewable energy sources appearing in rural areas have been described and the sensitivity of the optimization algorithm to the changes of demanded power values and changes of values of power generated by renewable energy sources has been studied. We analyzed different objective functions which can be used as an optimization goal both in synchronous and island operation modes of microgrid. We decided to intensively test our approach on a sample rural LV microgrid, which is typical in the countryside. The observed results of the tests have been presented and analyzed in detail. Generally, results achieved with the use of proposed distributed control are the same as with the use of centralized control. We think that the approach based on distributed control is promising for practical applications, because of its advantages.

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Authors and Affiliations

M. Parol
P. Kapler
J. Marzecki
R. Parol
M. Połecki
Ł. Rokicki
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Abstract

This paper presents a test stand equipped, among others, with two boilers intended for the combustion of solid fuels. The first is a single-fuel boiler designed to burn wood pellets only. The second is a multi-fuel boiler intended for the combustion of mainly hard coal (basic fuel) with the grain size of 0.005–0.025 m. Wood pellets can also be fired in this boiler, which in such a case are treated as a substitute fuel. There is a developed and verified algorithm for the control of the multi-fuel boiler operation in a wide range of loads for the basic fuel. However, for the substitute fuel (wood pellets) there are no documented and confirmed results of such testing. The paper presents selected results of testing performed during the combustion of wood pellets in a multi-fuel automatically stoked boiler. Several measuring series were carried out, for which optimal operating conditions were indicated. These conditions may serve as the basis for the development of the boiler operation control algorithm. A detailed analysis was carried out of the flue gas temperatures obtained at the outlet of the boiler combustion chamber and of the contents of carbon monoxide and oxygen in the boiler flue gases.
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Bibliography

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[2] Regulation of the Minister of Development and Finance on the requirements for solid-fuel boilers. Journal of Laws – Republic of Poland (Dziennik Ustaw Rzeczypospolitej Polskiej) 2017, Item 1690 (in Polish).
[3] EN 303-5:2021: Heating boilers – Part 5: Heating boilers for solid fuels, manually and automatically stoked, nominal heat output of up to 500 kW – Terminology, requirements, testing and marking.
[4] Poland’s Energy Policy until 2040. Ministry of Climate and the Environment, Appendix to Resolution 22/2021 of the Council of Ministers, 2021 (in Polish).
[5] Commission Regulation (EU) 2019/2146 amending Regulation (EC) 1099/2008 of the European Parliament and of the Council on energy statistics, as regards the implementation of updates for the annual, monthly and short-term monthly energy statistics. OJ L 325, 16.12.2019.
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Authors and Affiliations

Wiesław Zima
1
Grzegorz Ojczyk
2

  1. Cracow University of Technology, Department of Energy, al. Jana Pawła II 37, 31-864 Kraków, Poland
  2. MTHE Modern Technologies in Heating Engineering, Młynska-Boczna 7/2, 31-470 Kraków, Poland

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