Combustion problem identification based on electric power output oscillation assessment for Diesel-Engine driven generators

Abstract

One of the most critical situations in the operation of medium and low speed synchronous generators appears when they are subjected to torque imbalances. This could be the case of internal combustion engines driven generators. In these engines, torque has a periodic oscillation due to variations in the combustion process and pressure development between cylinders. Consequently, a fuel excess or a fuel deficiency in a cylinder produces an imbalance in the torque oscillation. So the detection of combustion failures is very important in order to avoid problems in generator performance. In a prior work, the authors have presented a diagnostic method that detects combustion failures caused by a fuel deficiency in a cylinder, even in their first stages. The purpose of this paper is to improve this diagnostic technique by including the effects of fuel excess. Thus, another cause of dangerous torque imbalances in generator operation can be avoided. Analyzing the harmonic order of the generator power output makes it possible to detect and identify the cylinder that is producing the imbalance. This new technique has been verified with adequate results in a 11.6 MVA/ 600 rpm/10 kV Diesel-Engine Driven Generator.