Performance of synchronous motors loss-of-synchronism protection
Synchronous motors are rarely designed to operate asynchronously for extended periods of time. When a synchronous motor experiences a mechanical load exceeding its pull out torque, it enters asynchronous operation, under which the interaction between the stator and rotor magnetic fields causes damaging mechanical stress and vibrations. Also, induced currents in the rotor cause extra heating that quickly damages the rotor windings. Asynchronous operation must be detected and dealt with by allowing time for resynchronization or by tripping the motor to avoid thermal overload and damage. Two protection elements are often used to detect asynchronous motor operation: the power factor element and the out-of-step element. This paper compares the performance of the two elements to protect a 20 MW synchronous motor subjected to pull out conditions.
Large synchronous motors for the Delaware City Repowering Project
The successful and profitable operation of a petroleum coke gasification project relies very heavily on a reliable source of oxygen produced from an air separation unit (ASU). The ASU for the Motiva Delaware City Repowering Project depends upon the proper application and operation of very large synchronous motors, including a four pole 66000 hp machine and a four pole 43000 hp machine; the former being the largest 1800 rpm compressor driver ever designed and manufactured. Specification development and supplier selection are summarized. The effects of motor starting on the power system with regard to voltage drop is outlined and discussed. Motor design issues relating to transient temperatures and stresses as well as torsional and lateral critical speeds are analyzed. Factory and commissioning test procedures that verify the motor electrical design, mechanical design, and performance are discussed.
State estimation for integrated vehicle dynamics control
This paper discusses a vehicle controller and a state estimator that was implemented and tested in a vehicle equipped with a combined braking and chassis control system to improve handling. The vehicle dynamics controller consists of a feed forward body roll compensation and a feedback stability controller. The estimator is based on a non-linear vehicle model combined with an extended Kalman filter. The Kalman filter is also connected to an algorithm, which estimates the tyre-road friction coefficient. The developed estimator was tested in a vehicle. Good results were achieved for normal and extreme driving manoeuvers.