An Electronic Protection Unit for Diesel Engine Standby Generators

Abstract

Today diesel engine-driven standby generators for backup power supply have been adopted for residential, commercial, and industrial use—especially in some developing countries where power from the utility company is highly erratic. Although many of these generators function well in operation, certain engine conditions, such as low oil pressure, high oil and water temperature, abnormally high speed, etc., could lead to malfunction, failure, or complete breakdown of the engine. Therefore, the focus of this work is to present the implementation of a simple, but effective electronic protection unit (EPU) capable of mitigating the adverse effect which may arise as a result of these conditions. It is composed of two major sub-circuits—the main protective sub-circuit and the timing sub-circuit—realized using a combination of passive and active components. Unlike the common electrical relay-based protection system, this unit has an additional advantage of being able to keep the fault-indicating system of the generator working even after engine shutdown, thereby facilitating fault tracking. The unit has been tested on a diesel engine-driven generator and found to function satisfactorily. The test results are shown.

Keywords: diesel engine, engine fault, protection, standby generator