Title Proširenje područja stabilnog rada sinkronog generatora regulacijom uzbude Title (english) Expanding stable operation region of synchronous generator by excitation control Author Tomislav Idžotić Mentor Gorislav Erceg (mentor)Committee member Drago Ban (član povjerenstva)Committee member Gorislav Erceg (član povjerenstva)Committee member Joško Deur (član povjerenstva)Committee member Tomislav Tomiša (član povjerenstva)Committee member Mario Žagar (član povjerenstva)Granter University of Zagreb Defense date and country 2003-12-19, Croatia Scientific / art field, TECHNICAL SCIENCES Universal decimal classificationUDC ) 621.3 - Electrical engineering Abstract Sinkroni generator se u kapacitivnom području rada približava granici stabilnosti i postaje osjetljiv na poremećaje u elektroenergetskom sustavu. Kut opterećenja pokazuje koliko je generator blizu granici stabilnosti, a povećavanjem struje uzbude generatora moguće je smanjiti kut opterećenja i povećati stabilnost generatora.
U klasični algoritam regulacije uzbude generatora, u kojem je regulator napona nadređen regulatoru struje uzbude, uveden je dodatni regulator kuta opterećenja koji se uključuje kada se generator približi granici stabilnosti. Tada se isključuje regulator napona generatora i uključuje regulator kuta opterećenja. Prelazak između ta dva regulatora je gladak.
Razvijena je i ispitana metoda estimacije kuta opterećenja generatora. Mjerene veličine potrebne za estimaciju kuta opterećenja su dva napona i dvije struje generatora. Eksperimentalni rezultati pokazuju dobro slaganje estimiranog i mjerenog kuta kako u statičkim tako i dinamičkim uvjetima osim kada generator ispada iz sinkronizma. Potvrđena je primjenjivost estimiranog kuta opterećenja u regulacijskim algoritmima proširenja područja stabilnog rada generatora regulacijom uzbude.
Realiziran je četveroprocesorski digitalni sustav baziran na procesorima za obradu signala. Unutar digitalnog sustava implementiran je estimator kuta opterećenja, sinkronizator generatora na elektroenergetsku mrežu i regulacijski algoritmi (regulator radne i jalove snage generatora, napona generatora, struje uzbude generatora, brzine vrtnje turbine i regulator kuta opterećenja). Napravljeni su programski alati koji se izvode na osobnom računalu potrebni za razvoj i ispitivanje algoritama regulacije.
Sustav regulacije uzbude generatora je složeni nelinearni višeparametarski sustav. Sustav se sastoji od generatora spojenog na elektroenergetski sustav, čopera i digitalnog sustava sa mjernim članovima. Za svaki dio sustava napravljen je matematički model. Pojedini dijelovi su spojeni u jedinstveni model sustava uzbude.
U sustavu regulacije uzbude generatora, regulator jalove snage i napona generatora imaju PI karakteristiku, regulator estimiranog kuta opterećenja ima PID karakteristiku, a regulator struje uzbude P karakteristiku.
Načinjen je simulacijski model sustava regulacije uzbude generatora u programskom paketu “MATLAB-SIMULINK“.
Rezultati dobiveni simulacijom za slučaj skokovite promjene reference (struje uzbude, napona, jalove snage) kao i za slučaj promjene radnog opterećenja generatora pokazuju dobro slaganje s rezultatima dobivenim eksperimentom.
Simulacijski model se koristi za optimiranje parametara regulatora i za ispitivanje djelovanja algoritama u uvjetima koji se teško mogu eksperimentalno ispitati (pokus kratkog spoja, pokusi na generatorima velike snage).
Eksperimentom i simulacijom provedena ispitivanja pokazuju pozitivno djelovanje regulatora kuta opterećenja i primjenjivost estimiranog kuta opterećenja u algoritmima proširenja područja stabilnog rada generatora regulacijom uzbude.
Abstract (english) A synchronous generator in capacitive region of operation is near stability limit and becomes sensitive to extreme situations in electrical network. Load angle of generator shows how generator is far from stability limit. Load angle can be decreased by increasing excitation current.
Classical algorithms of excitation control contains voltage controller which is superior to excitation current controller. This thesis describes a new algorithm of excitation control in which load angle controller is included. Load angle controller is turned on when generator is near stability limit. Then the voltage controller is off. Transition from voltage to load angle controller is smooth.
Load angle estimation method is developed. Generator variables for estimation are two generator voltage and two generator currents. Experimental results show little error in estimation of load angle in static as well in dynamic terms. Big error of load angle estimation occurs when generator falls from synchronicity with electrical network. Load angle estimation method is fully tested and it can be applied in proposed algorithms of expanding stable operation region of synchronous generator by excitation control.
Four processor digital system is developed. Digital system contains all algorithms for load angle estimation, self synchronization unit and all needed controllers (reactive and active power controller, voltage controller, excitation current controller, generator speed controller and load angle controller). Software tools for PC are developed for making algorithms in graphical environment and for testing of algorithms.
Generator excitation system is complex nonlinear and multivariable system. System contains generator connected to electrical network, DC converter and digital system with measuring devices. All that parts are connected in common mathematical model of excitation control.
Reactive power controller and generator voltage controller has PI characteristics, excitation current controller has P characteristics and load angle controller has PID characteristics.
Mathematical model of excitation control is simulated using “MATLAB-SIMULINK“ simulation software package.
Results from simulation of reference step change (excitation current reference, generator voltage and reactive power reference) and results from stepwise change of generator load shows good alignment of simulation results to experimental results.
Simulation model is used for optimization of controller parameters and testing of algorithms in terms which are not possible to get experimentally (short circuit experiment, tests on high power generators).
Experimental and simulation results shows positive performance of load angle controller and full applicability of load angle estimation in algorithms of expanding stable operation region of synchronous generator by excitation control.
Keywords
Sinkroni generator
digitalni sustav
uzbuda generatora
regulacija napona
regulacija kuta opterećenja
estimirani kut opterećenja
Keywords (english)
Synchronous generator
digital system
generator excitation
voltage control
load angle control
load angle estimation
Language croatian URN:NBN urn:nbn:hr:168:000038 Study programme Title: Doctoral study programme "Electrical Engineering and Computing" Type of resource Text File origin Born digital Access conditions Closed access Terms of use Created on 2019-06-27 12:54:33
