A METHOD FOR EXPRESS ASSESSMENT OF PI-REGULATOR PARAMETERS FOR APERIODIC TRANSIENT PROCESSES IN AUTOMATIC CONTROL SYSTEMS OF NUCLEAR POWER PLANT UNITS
Abstract
This article discusses the key aspects of setting the parameters of automatic regulators that are used in process control systems, in particular at nuclear power plants (NPP). The need for fine-tuning regulators is emphasized to ensure the stability, efficiency and safety of the systems. Traditional tuning methods such as the Ziegler-Nichols method and frequency analysis are described, which, despite their reliability, require significant time and an accurate mathematical model of the control object. In modern production conditions, where efficiency is important, express methods are relevant to reduce setup time, but their accuracy and versatility remain questionable. Special attention is paid to the problems that arise when using real regulators, such as integral saturation and periodic invocation of the control algorithm. Integral saturation can lead to a deterioration in the dynamic characteristics of the system and even to the activation of technological protections, and an incorrect choice of the period for calling the regulator can cause a loss of stability of the system. Methods A method for tuning PI controllers is proposed that takes into account the dynamic characteristics of control objects and the results of experimental studies. Recommendations are given on the choice of proportionality coefficients and the integration time constant, which make it possible to achieve an aperiodic transition process, minimize the risk of saturation and ensure high quality control. Results The results of experiments conducted on the UMICON software and hardware complex confirmed the effectiveness of the proposed approach. Conclusion. The developed rules for rapid evaluation of regulator parameters make it possible to simplify the setup process, reduce setup time, and improve the reliability of automatic control systems at nuclear power plants. This is especially important to ensure the safety and stability of such critical facilities as nuclear power plants.
References
1. Squassoni S. The incredible shrinking nuclear offset to climate change, Bulletin of the atomic scientists, 2017, Vol. 73, No. 1, pp. 17-26.
2. Saakov E.S., Ryasnyy S.I. Vvod v ekspluatatsiyu energoblokov AES [Commissioning of NPP power units]. Moscow: Energoatomizdat, 2007, 496 p.
3. Rotach V.Ya. Raschet nastroyki real'nykh PID-regulyatorov [Calculation of real PID controller tuning], Teploenergetika [Thermal Engineering], 1993, No. 10, pp. 31-35.
4. Rotach V.Ya., Kuzishchin V.F., Klyuev A.S. i dr. Avtomatizatsiya nastoyki sistem upravleniya [Automa-tion of control system tuning]. Moscow: Energoatomizdat, 1984, 272 p.
5. Denisenko V.V. Komp'yuternoe upravlenie tekhnologicheskim protsessom, eksperimentom, oborudo-vaniem [Computer control of technological processes, experiments and equipment]. Moscow: Goryachaya liniya – Telekom, 2014, 606 p.
6. Gustav Olsson, Dzhanguido Piani. Tsifrovye sistemy avtomatizatsii i upravleniya [Digital automation and control systems]. Saint Petersburg: Nevskiy Dialekt, 2001, 557 p.
7. Gudvin G.K., Grebe S.F., Sal'gado M.E. Proektirovanie sistem upravleniya [Control system design]. Moscow: BINOM. Laboratoriya znaniy, 2004, 911 p.
8. Åström, K.J., and Hägglund, T. PID Controllers: Theory, Design, and Tuning. 2nd ed. NC, Instrument Society of America. 1995.
9. Åström, K.J., and Hägglund, T. Automatic Tuning of Simple Regulators with Specifications on Phase and Amplitude Margins, Automatica, 1984, 20 (5), pp. 645-651.
10. Weng Khuen Ho, Chang Chieh Hang, and Lishens S. Cao. Tuning of PID Controllers Based on Gain and Phase Margin Specification, Automatica, 1995, 31 (3), pp. 497-502.
11. Rotach V.Ya. Raschet nastroyki real'nykh PID-regulyatorov [Calculation of real PID controller tuning], Teploenergetika [Thermal Engineering], 1993, No. 10, pp. 31-35.
12. Stefani E.P. Osnovy rascheta nastroyki regulyatorov teploenergeticheskikh protsessov [Fundamentals of heat power process controller tuning calculations]. 2-e ed. Moscow: Energiya, 1972, 376 p.
13. Sanchis R., Romero J.A. and Balaguer P. PI and PID auto-tuning procedure based on simplified single parameter optimization, Journal of process control, 2011, Vol. 21, pp. 840-851.
14. Garpinger O., Hägglund T. and Åström K.J. Performance and robustness trade-offs in PID control, Journal of Process Control, 2014, Vol. 24, pp. 568-577.
15. O’Dwyer Aidan. Handbook of PI and PID controllers tuning rules. 3rd ed. London, Imperial College Press, 2009.
16. Vilanova Ramon, and Visioli Antonio. PID Control in the Third Millenium, Lessons Learned and New Approaches. London, Springer-Verlag, 2012.
17. Skogestad S. Simple analytic rules for model reduction and PID controller tuning, Journal of Process Control, 2003, Vol. 13, pp. 291-309.
18. Prokhorov A.N., Lysachev M.N. Tsifrovoy dvoynik. Analiz, trendy, mirovoy opyt [The digital double. Analysis, trends, and global experience]. 1st ed. Moscow: OOO «Al'yansPrint», 2020, 401 p.
19. Programmno-tekhnicheskiy kompleks «Virtual'no-tsifrovaya AES s VVER» [Software and hardware complex "Virtual digital NPP with VVER"]. Institute of Problems of Safe Development of Atomic En-ergy of the Russian Academy of Sciences [website]. Available at: http://www.ibrae.ac.ru/contents/362.
20. MU-UZHTSASU.09.06 Metodicheskie ukazaniya «Analiz ustoychivosti konturov avtomaticheskogo regulirovaniya». Reviziya 1. AO «RASU» [MU-UZHTSASU.09.06 Methodological guidelines "Stabil-ity analysis of automatic control circuits". Revision 1. RASU JSC].
