The paper the auxiliary control loop a static VAR system using concept - PDF document

The paper the auxiliary control loop a static VAR system using concepts. Also, the controller using the least number synchronous generator power system infinite busbar the results to a system. is straightforward, and in the near System model the schematic diagram generator connected double-circuit transmission line, represented lumped reactance, busbar. The synchronous generator a third-order nonlinear mathematical model, represented equipped with and a the genera- provide significant damping compensator comprises fixed caipacitor its block dia- control loop stabilising signals, such speed, fre- quency, phase angle improve the dynamic performance the integrated Another alternative location also considered in this computer simula- The magnitude the firing angle busbar voltage, MVA rating capacitor and capacitive reactance. from the maximum the busbar the compensator in the capacitive region the inductive one the short-circuit power level of of at which the SVC is located. A dynamic sta- the power values of operating conditions. the development auxiliary control these aspects equations, after dynamic equations equations - ___ - 4 7-A7 a1 a1 where a1 = z&(1- z,B,) + 2, U: = 2d(1 - GBs) + 2, a2 = zq(l - 53,) + z, (4) However, if the SVC is located at an intermediate bus- dividing the transmission having reactances deriving the varia- simple sliding mode controllers. following Section outlines the details variable structure fuzzy controller This Section outlines the the rule-based the auxiliary control loop Linguistic variables membership functions, fuzzy set has two fuzzy set has two members three members The input and rules (four membership functions obtained, using trapezoidal membership acteristics, as three the the three enable the to operate for the compositional rule The control evaluated using Zadeh Lukasiewicz logic Control output engine of matches the preconditions the rules in the rule base with state linguistic terms error and rate, the firing strengths obtained as stands for operation and The control any rule matching the strength its precondition its conclu- have the same evaluate the centroid defuzzification technique, the incre- the values control out- the membership in the each equal fication algorithm the incremental incremental 141, the nonlinear limiting rules controller presented above gains vary the mag- its rate. provide significant damping during transient the power a robust control during nificant changes in operating conditions cope in such situations, combined with special class structure upon ing hyperplanes the hyperplane, the system becomes noise distur- auxiliary con- constant and its initial initial ~~~1 = 0 [;is] + [1] Au (17) 93 0 94 where the constants gl - g are given in Appendix switching hyperplane the parameters switching surface from eqn. the characteristic the reduced state obtained as the parameter the various stability criterion choose the the linearised obtained as as 91 0 92 ] (32) Choosing ge and gr as 0 1 0 93 + glg5x2 g5x1 94 + g2g5x2 ge = 1/Aumaz gr = l/AGmax (33) - gmns - ABS i = (cl - c2g4)Aw + czAW + (g3 - clg4)ab + g5au (23) Choosing the value within their limiting in eqn. the integral squared in the The incremental control written as Control Output the value the reaching condition in the following Substituting the value in eqn. the value the deviation in the generator terminal the change busbar. Fig. Computer simulation Substituting the maximum value in terms sgn (sign) layer concepts reduce chattering problems in sliding constant for this case. used, the made robust fuzzy, sliding on a nous generator connected infinite busbar transient disturbances. Also, the performance the auxiliary signal is highlight the these controllers using synchronous generator the fol- lowing parameters Fuzzy controller: IEE Proc.-Gene?. Trunsm. Distrib., following case studies for a the infinite in Figs. for conventional, variable structure VAR stabilisers. conventional VAR stabiliser the Figures, quite evident to the VAR controller comparable. However, the conventional stabiliser without any auxiliary control Transient performance 3-phase short-circuit the infinite generator terminal) Transient performance 3-phase short-circuit the infinite terminal) P response curves for a 3-phase short-circuit the infinite busbar on one the double-circuit transmission and the the superior variable structure the auxiliary control the vari- structure stabiliser controller provides the auxiliary control conventional controller auxiliary control 5 6 7 Transient performance 3-phase short-circuit the infinite terminal) P 3-phase short-circuit 5 6 3-phase short-circuit When the at any busbar terminal, the load angle not available for control. Instead, the bus- frequency deviations obtain the auxiliary control input the variable structure control, a provide the control input. As the prime aim establish the efficacy of controllers, the the conventional control and one circult one circuit depict the transient response characteristics power system for a 3-phase short-circuit near the infinite busbar cleared in the short-circuit, increasing the the results, it provides significant damping system oscilla- Proc.-Gener. Transm. These results those presented presented using bang-bang control phase angle deviation feedback. turbine input turbine input for rotor sudden change the supe- rior performance system oscillations. this simulation, validating the assumption the controller to parameter and operating point require gain schedul- ings in response with the in general, better the conventional the generator controller produces comparison with those described in the latest latest on VAR control. the concept controller increases the tuning property better performance. the prime nonlinear controller using the linguistic properties static VAR control and static control for The paper presents the applications the stabilising VAR compensator ing transient disturbances. compared with without auxiliary are found comparison with the conventional controller provides damping in comparison with controller during transient disturbances. How- accurate mathematical model require consideration controller with minimum number highly effective in the conventional VAR stabilisers. 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