Investigation of impact of electric motor repair and rewinding practices for restoration of efficiency of motor systems: The case of Tanzania Planting Company Ltd.

Abstract

ABSTRACT Tanzania Electric Supply Company (TANESCO) is currently implementing a combination of maintenance practices which are Corrective, Breakdown and Preventive maintenance to most of its Substations including Nyakato substation in Mwanza. However, these types of maintenance do not sufficiently reduce the frequent failures of Substation equipment. For example, the power requirement for the Mwanza region was fulfilled by 83% in the period of December 2013 to November 2014 due to frequent failures of equipment at the Substation which affect the company reliability.

In this study a survey was conducted mainly on the 220kV and 132kV sides of the Substation. RCM system using Computerized Maintenance Management System for the reliability of the substation was developed after conducting reliability analysis for the Nyakato substation that involved the identification failure modes affecting the substation reliability and analysis of their potential causes.

Data used for the analysis of the Substation reliability were collected through interviews, questionnaire, site visits and literature available at the Substation. The data collected included those which contributed to the Substation failures. It was also observed that the was power supply inefficiency at Nyakato substation due to the breakdown maintenance, lack of skills and experience of maintenance operation personnel and lack of genuine spare parts, current maintenance practice where by breakdown maintenance is much practiced at the substation, lack on skills and experience of maintenance and operation personnel and lack of genuine spare parts.

The RCM System using Computerized Maintenance Management System (CMMS) showed improvement in power reliability by increasing substation equipment reliability and relatively reducing power outages to customers.

Implementation of the developed system optimized equipment availability and reliability at Nyakato substation. Optimization was assessed by comparison of maintenance practice before and after developed RCM system. The developed system showed the improvement on availability and reliability by 4.074% and 4.162% respectively.