Divided Winding Rotor Research Articles

Performance of a divided winding rotor machine with optimal controllers

A state-space model of a power system, where the long transmission line is represented by the constants A, B, C and D of its equivalent π-network (shunt compensating reactors are also taken into consideration), with a divided winding rotor (d-w-r) synchronous generator is obtained with an all-measurable state vector. The damping of the system with conventional excitation and prime mover controllers acting alone and with (a) optimal controllers and (b) optimal controllers with a prescribed degree of stability is assessed from the eigenvalue placement of the resultant closed-loop systems. Both controllers (a) and (b) referred to above, synthesized for full-load operating conditions, were tested under different load conditions to ascertain the feasibility of obtaining a fixed controller to cover a wide range of operating conditions.

STABILITY OF D.W.R. SYNCHRONOUS GENERATOR AS AFFECTED BY FORCED EXCITATION SYSTEMS

ABSTRACT Dynamic stability of a divided winding rotor synchronous generator Is determined by co-ordination of regulator parameters obtained by applying D-decomposition technique. Transient stability is evaluated by simulating faults like (a) sudden 3-phase short circuit, (b) sustained loss of excitation in either of the field windings. Results are compared with the transient simulation made on the same generator equipped with regulators, as described by previous authors

Fault Simulation of Divided Winding Rotor Synchronous Generator with Rectifier Excitation

Abstract A mathematical model of a divided winding rotor synchronous generator is developed on an actual field winding basis. The generator is assumed to have a rectifier excitation scheme for its field windings and is connected to an infinite bus. Transient stability studies were made by considering a three-phase short-circuit in the transmission line and multiple faults such as an external fault together with a sustained fault in the excitation channel. From these studies it is observed that quick reversal of the reactive winding current and the role of the torque winding current during faults, especially when the machine is operating at leading power factor, are most vital in maintaining stability. It is also found that the system becomes less stable when it undergoes a dual fault and stability is further reduced if the torque winding current is constrained to zero.

OPTIMAL REGULATORS FOR SOLID ROTOR D. W. R. SYNCHRONOUS GENERATOR BY OUTPUT FEEDBACK

ABSTRACT The paper deals with the design of optimal regulators (continuous and discrete) for divided winding rotor (d. w. r.) synchronous generator by output feedback using pole placement technique where the machine model includes in detail the solid-iron effect of the rotor body. The effect of solid rotor on the design of regulators' gains has been estimated. The effect of saturation of the rotor body on the design of continuous regulators and the effect of sampling period on the design of discrete regulators have also been studied. Finally, a comparison is made between the feedback gain values obtained from continuous and discrete models.

Stabilization of linear system behaviour by pole shifting

The problem of determining the output feedback control matrix such that the system is as stable as possible is considered from the point of view of minimizing the real part of the least stable eigenvalue of the system. To ensure reasonable control and system behaviour, minimum and maximum constraints are placed on each element of the feedback matrix. An effective algorithm is given to carry out the pole shifting. The feasibility of the approach is illustrated with an eight-state three-feedback linearized model of a divided winding rotor synchronous machine and a linear six-plate gas absorber.

Optimal controllers for divided winding rotor synchronous machine†

The state-space model for the divided winding rotor (d.w.r.) synchronous machine is derived in a form most suitable for the application of optimal control theory. An optimal controller for the machine is designed to improve the dynamic respose of the power system. The superiority in the performance of the system with the optimal state controller as compared with that of a conventional voltage and angle regulator is conclusively established.

Stability of synchronous machine with divided-winding rotor

To deal with a divided-winding rotor (d.w.r.) synchronous machine in which the two field windings are not located on the rotor axes and may not have equal numbers of turns, an equivalent machine is introduced with field windings on the direct and quadrature axes. The steady-state stability calculations are carried out by applying the Nyquist criterion to the linearised equations for small oscillations of a system with more than one feedback regulator. This investigation is followed by using the nonlinear differential equations and a digital computer to find the transient response after a change in the tieline impedance. The calculated results are confirmed by experiments carried out on the micromachine equipment at Imperial College, London. The alternatives studied included systems using one regulator at a time, both regulators together and various transfer functions for each regulator. The main conclusion is that the angle regulator stabilises the voltage regulator and has a major influence on the stability of the system; hence the voltage-regulator gain can be varied over a wide range.

Stability of synchronous machine with divided-winding rotor

To deal with a divided-winding rotor (d.w.r.) synchronous machine in which the two field windings are not located on the rotor axes and may not have equal numbers of turns, an equivalent machine is introduced with field windings on the direct and quadrature axes. The steady-state stability calculations are carried out by applying the Nyquist criterion to the linearised equations for small oscillations of a system with more than one feedback regulator. This investigation is followed by using the nonlinear differential equations and a digital computer to find the transient response after a change in the tieline impedance. The calculated results are confirmed by experiments carried out on the micromachine equipment at Imperial College, London. The alternatives studied included systems using one regulator at a time, both regulators together and various transfer functions for each regulator. The main conclusion is that the angle regulator stabilises the voltage regulator and has a major influence on the stability of the system; hence the voltage-regulator gain can be varied over a wide range.

Stability of synchronous machine with divided-winding rotor

Stability of synchronous machine with divided-winding rotor