Synchronous Starting Research Articles

Starting of Large Synchronous Motor Using Static Frequency Converter

This paper deals with the synchronous starting of a large synchronous motor, using a static thyristor frequency converter system. This method, in the following called, Converter Starting, is described. Special inverter questions are treated and the results of analytical and computer studies of the system and of a field test are presented. Potential applications of the method are dewatered starting in the pumping mode of reversible pumped-storage generator/motors and the starting of large synchronous condensers. The same equipment can also be used for braking the machines.

Erratum: Discussion on ‘Starting methods for generator/motor units employed in pumped storage stations’ and ‘Investigation into damping-torque coefficients and stability of a 2-synchronous-machine system employed in synchronous starting’

Erratum: Discussion on ‘Starting methods for generator/motor units employed in pumped storage stations’ and ‘Investigation into damping-torque coefficients and stability of a 2-synchronous-machine system employed in synchronous starting’

Discussion on “Starting methods for generator/motor units employed in pumped-storage stations” and “Investigation into damping-torque coefficients and stability of a 2-synchronous-machine system employed in synchronous starting”

Discussion on “Starting methods for generator/motor units employed in pumped-storage stations” and “Investigation into damping-torque coefficients and stability of a 2-synchronous-machine system employed in synchronous starting”

Starting methods for generator/motor units employed in pumped-storage stations

Arrangements which must be made for starting reversible pumped-storage plant in the pumping mode are reviewed, and the alternative starting methods are discussed. It is necessary to study the starting process in detail, together with the effect this has on the power system, because of the capacity of large pumped-storage plant, with the requirement that the machines be started during periods of low demand. The method chosen must be technically sound, reliable and economic. Two starting methods are considered in detail: asynchronous starting and synchronous starting. Disturbances imposed on the power system by the starting process are particularly important in asynchronous starting. The method discussed is related principally to the Korndorfer procedure. The effect on starting performance of varying the system constraints, together with the effect of other criteria, is examined. Theoretical predictions are compared in specific cases with test results obtained on conventional hydroelectric plant relating to both asynchronous and synchronous starting, to verify the representation employed. Typical theoretical results relating to 2 × 150MW and 4 × 300MW schemes are given.

Investigation into damping-torque coefficients and stability of a 2-synchronous-machine system employed in synchronous starting

The region of minimum damping for a 2-machine system, which occurs at low speeds, in which self-excited hunting may take place is investigated. Under certain circumstances, it is shown that, even where machines are provided with satisfactory damper windings, negative-damping phenomena may be exhibited. A transfer function for a 2-machine system is set up to which various stability criteria may be applied. Frequency-response curves for a typical system which may be employed in a large pumped-storage scheme are given. The rotor oscillations obtained by tests on an actual system are reproduced, and comparisons are made with predictions obtained by application of the stability-criteria method which is developed.

Synchronous Starting of Motor from Generator of Small Capacity

The results are presented of a computer study of the synchronous starting of a synchronous pumped storage generator motor from a generator having approximately 15 percent of the motor's capacity. In synchronous starting both motor and generator are initially at rest with excitation applied. The effects of system parameters such as armature circuit resistance, generator saturation, relative excitation on the two machines, amortisseur characteristics, initial starting angle, motor friction torque, gate leakage torque, and rate of application of torque were studied. Some of the more important conclusions are: synchronous starting with a generator of 15 percent size is entirely feasible, the most important electrical parameter is the generator armature resistance, a good amortisseur is desirable on the motor, there is a maximum generator torque that can usefully be applied, and any higher torque may simply cause the generator to run away. Gate leakage torque can be a more serious limitation than friction torque.

Recent Developments in Starting Cross-Compound Turbine-Generator Units

This paper develops the fundamental theory of synchronizing and loss torques in a-c machines at turming-gear speed, and shows the practical application of this theory to the synchronous starting of cross-compound turbine-generator units by the use of the shaft-position indicator and 2-speed turning-gear motors. The steam by-pass method of starting crosscompound units having shaft-driven exciters and no spare motor-driven exciter is also described.

Synchronous starting of generator and motor

Synchronous starting of generator and motor

Synchronous starting of generator and motor

Synchronous starting of generator and motor